Initial commit

.gitignore

@@ -0,0 +1,106 @@
+# Extensions
+
+*.a
+*.bat
+*.bin
+*.d
+*.dll
+*.dot
+*.etag
+*.exe
+*.gcda
+*.gcno
+*.gcov
+*.gguf
+*.gguf.json
+*.lastModified
+*.log
+*.metallib
+*.o
+*.so
+*.tmp
+
+# IDE / OS
+
+.cache/
+.ccls-cache/
+.direnv/
+.DS_Store
+.envrc
+.idea/
+.swiftpm
+.vs/
+.vscode/
+nppBackup
+
+
+# Coverage
+
+gcovr-report/
+lcov-report/
+
+# Build Artifacts
+
+tags
+.build/
+build*
+!build-info.cmake
+!build-info.cpp.in
+!build-info.sh
+!build.zig
+!docs/build.md
+/libllama.so
+/llama-*
+/vulkan-shaders-gen
+android-ndk-*
+arm_neon.h
+cmake-build-*
+CMakeSettings.json
+compile_commands.json
+ggml-metal-embed.metal
+llama-batched-swift
+/rpc-server
+out/
+tmp/
+autogen-*.md
+
+# CI
+
+!.github/workflows/*.yml
+
+# Models
+
+models/*
+models-mnt
+!models/.editorconfig
+
+# Zig
+
+# Logs
+
+
+
+# Examples
+
+
+# Server Web UI temporary files
+node_modules
+examples/server/webui/dist
+
+# Python
+
+/.venv
+__pycache__/
+*/poetry.lock
+poetry.toml
+
+# Nix
+/result
+
+# Test binaries
+
+# Scripts
+
+# Test models for lora adapters
+
+# Local scripts

CMakeLists.txt

@@ -0,0 +1,62 @@
+cmake_minimum_required(VERSION 3.10)
+project(humanus.cpp VERSION 0.1.0)
+
+set(CMAKE_CXX_STANDARD 17)
+set(CMAKE_CXX_STANDARD_REQUIRED ON)
+
+# 查找OpenSSL库，尝试查找3.0.0版本，但如果找不到，也接受其他版本
+find_package(OpenSSL REQUIRED)
+if(OPENSSL_FOUND)
+    message(STATUS "OpenSSL found: ${OPENSSL_VERSION}")
+    message(STATUS "OpenSSL include directory: ${OPENSSL_INCLUDE_DIR}")
+    message(STATUS "OpenSSL libraries: ${OPENSSL_LIBRARIES}")
+    include_directories(${OPENSSL_INCLUDE_DIR})
+    add_compile_definitions(CPPHTTPLIB_OPENSSL_SUPPORT)
+else()
+    message(FATAL_ERROR "OpenSSL not found. Please install OpenSSL development libraries.")
+endif()
+
+# 查找Python库
+find_package(Python3 COMPONENTS Development)
+if(Python3_FOUND)
+    message(STATUS "Python3 found: ${Python3_VERSION}")
+    message(STATUS "Python3 include directory: ${Python3_INCLUDE_DIRS}")
+    message(STATUS "Python3 libraries: ${Python3_LIBRARIES}")
+    include_directories(${Python3_INCLUDE_DIRS})
+    add_compile_definitions(PYTHON_FOUND)
+else()
+    message(WARNING "Python3 development libraries not found. Python interpreter will not be available.")
+endif()
+
+# 添加MCP库
+add_subdirectory(${CMAKE_CURRENT_SOURCE_DIR}/mcp)
+
+# 添加服务器组件
+add_subdirectory(${CMAKE_CURRENT_SOURCE_DIR}/server)
+
+# 添加包含目录
+include_directories(${CMAKE_CURRENT_SOURCE_DIR})
+include_directories(${CMAKE_CURRENT_SOURCE_DIR}/include)
+include_directories(${CMAKE_CURRENT_SOURCE_DIR}/mcp/include)
+include_directories(${CMAKE_CURRENT_SOURCE_DIR}/mcp/common)
+
+# 查找必要的包
+find_package(Threads REQUIRED)
+
+# 添加源文件
+file(GLOB_RECURSE SOURCES 
+    "src/*.cpp"
+    "src/*.cc"
+)
+
+# 添加可执行文件
+add_executable(humanus_cpp ${SOURCES} main.cpp)
+
+# 链接库
+target_link_libraries(humanus_cpp PRIVATE Threads::Threads mcp server ${OPENSSL_LIBRARIES})
+if(Python3_FOUND)
+    target_link_libraries(humanus_cpp PRIVATE ${Python3_LIBRARIES})
+endif()
+
+# 安装目标
+install(TARGETS humanus_cpp DESTINATION bin) 

agent/base.h

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+#ifndef HUMANUS_AGENT_BASE_H
+#define HUMANUS_AGENT_BASE_H
+
+#include "../llm.h"
+#include "../schema.h"
+#include "../logger.h"
+
+namespace humanus {
+
+/**
+ * Abstract base class for managing agent state and execution.
+ * Provides foundational functionality for state transitions, memory management,
+ * and a step-based execution loop. Subclasses must implement the `step` method.
+ */
+struct BaseAgent : std::enable_shared_from_this<BaseAgent> {
+    // Core attributes
+    std::string name; // Unique name of the agent
+    std::string description; // Optional agent description
+
+    // Prompts
+    std::string system_prompt; // System-level instruction prompt
+    std::string next_step_prompt; // Prompt for determining next action
+
+    // Dependencies
+    std::shared_ptr<LLM> llm; // Language model instance
+    std::shared_ptr<Memory> memory; // Agent's memory store
+    AgentState state; // Current state of the agent
+
+    // Execution control
+    int max_steps; // Maximum steps before termination
+    int current_step; // Current step in execution
+
+    int duplicate_threshold; // Threshold for duplicate messages
+
+    BaseAgent(const std::string& name, 
+            const std::string& description, 
+            const std::string& system_prompt,
+            const std::string& next_step_prompt,
+            int max_steps = 10,
+            int current_step = 0,
+            int duplicate_threshold = 2) : 
+        name(name), description(description), system_prompt(system_prompt), next_step_prompt(next_step_prompt), max_steps(max_steps), current_step(current_step), duplicate_threshold(duplicate_threshold) {
+            state = AgentState::IDLE;
+        }
+
+    // Initialize agent with default settings if not provided.
+    BaseAgent* initialize_agent() {
+        if (!llm) {
+            llm = LLM::get_instance(name);
+        }
+        if (!memory) {
+            memory = std::make_shared<Memory>();
+        }
+        return this;
+    }
+
+    // Add a message to the agent's memory
+    void update_memory(const std::string& role, const std::string& content) {
+        if (role == "user") {
+            memory->add_message(Message::user_message(content));
+        } else if (role == "assistant") {
+            memory->add_message(Message::assistant_message(content));
+        } else if (role == "system") {
+            memory->add_message(Message::system_message(content));
+        } else if (role == "tool") {
+            memory->add_message(Message::tool_message(content));
+        }
+    }
+
+    // Execute the agent's main loop asynchronously
+    virtual std::string run(const std::string& request) {
+        if (state != AgentState::IDLE) {
+            throw std::runtime_error("Cannot run agent from state" + agent_state_map[state]);
+        }
+
+        if (!request.empty()) {
+            update_memory("user", request);
+        }
+
+        state = AgentState::RUNNING;
+        std::vector<std::string> results;
+        while (current_step < max_steps && state == AgentState::RUNNING) {
+            current_step++;
+            logger->info("Executing step " + std::to_string(current_step) + "/" + std::to_string(max_steps));
+            std::string step_result = step();
+
+            if (is_stuck()) {
+                this->handle_stuck_state();
+            }
+
+            results.push_back("Step " + std::to_string(current_step) + ": " + step_result);
+        }
+        if (current_step >= max_steps) {
+            results.push_back("Terminated: Reached max steps (" + std::to_string(max_steps) + ")");
+        }
+        state = AgentState::IDLE;
+
+        std::string result_str = "";
+
+        for (const auto& result : results) {
+            result_str += result + "\n";
+        }
+
+        if (result_str.empty()) {
+            result_str = "No steps executed";
+        }
+
+        return result_str;
+    }
+
+    /**
+     * Execute a single step in the agent's workflow.
+     * Must be implemented by subclasses to define specific behavior.
+     */
+    virtual std::string step() = 0;
+
+    // Handle stuck state by adding a prompt to change strategy
+    void handle_stuck_state() {
+        std::string stuck_prompt = "\
+        Observed duplicate responses. Consider new strategies and avoid repeating ineffective paths already attempted.";
+        next_step_prompt = stuck_prompt + "\n" + next_step_prompt;
+        logger->warn("Agent detected stuck state. Added prompt: " + stuck_prompt);
+    }
+
+    // Check if the agent is stuck in a loop by detecting duplicate content
+    bool is_stuck() {
+        const std::vector<Message>& messages = memory->messages;
+
+        if (messages.size() < duplicate_threshold) {
+            return false;
+        }
+
+        const Message& last_message = messages.back();
+        if (last_message.content.empty() || last_message.content.is_null()) {
+            return false;
+        }
+
+        // Count identical content occurrences
+        int count = 0;
+        for (auto r_it = messages.rbegin(); r_it != messages.rend(); ++r_it) {
+            const Message& message = *r_it;
+            if (message.role == "assistant" && message.content == last_message.content) {
+                count++;
+                if (count >= duplicate_threshold) {
+                    break;
+                }
+            }
+        }
+
+        return count >= duplicate_threshold;
+    }
+
+    void set_messages(const std::vector<Message>& messages) {
+        memory->set_messages(messages);
+    }
+};
+
+}
+
+#endif // HUMANUS_AGENT_BASE_H

agent/manus.h

@@ -0,0 +1,64 @@
+#ifndef HUMANUS_AGENT_MANUS_H
+#define HUMANUS_AGENT_MANUS_H
+
+#include "base.h"
+#include "toolcall.h"
+#include "../prompt.h"
+#include "../tool/tool_collection.h"
+#include "../tool/python_execute.h"
+#include "../tool/terminate.h"
+#include "../tool/google_search.h"
+#include "../tool/file_saver.h"
+
+namespace humanus {
+
+/**
+ * A versatile general-purpose agent that uses planning to solve various tasks.
+ * 
+ * This agent extends PlanningAgent with a comprehensive set of tools and capabilities,
+ * including Python execution, web browsing, file operations, and information retrieval
+ * to handle a wide range of user requests.
+ */
+struct Manus : ToolCallAgent {
+    std::string name = "manus";
+    std::string description = "A versatile agent that can solve various tasks using multiple tools";
+
+    std::string system_prompt = prompt::manus::SYSTEM_PROMPT;
+    std::string next_step_prompt = prompt::manus::NEXT_STEP_PROMPT;
+    
+
+    Manus(
+        const ToolCollection& available_tools = ToolCollection(
+            {
+                std::make_shared<PythonExecute>(),
+                std::make_shared<Puppeteer>(),
+                std::make_shared<FileSystem>(),
+                std::make_shared<Terminate>()
+            }
+        ),
+        const std::string& tool_choice = "auto",
+        const std::set<std::string>& special_tool_names = {"terminate"},
+        const std::string& name = "manus",
+        const std::string& description = "A versatile agent that can solve various tasks using multiple tools",
+        const std::string& system_prompt = prompt::manus::SYSTEM_PROMPT,
+        const std::string& next_step_prompt = prompt::manus::NEXT_STEP_PROMPT,
+        int max_steps = 30,
+        int current_step = 0,
+        int duplicate_threshold = 2
+    ) : ToolCallAgent(
+        available_tools,
+        tool_choice,
+        special_tool_names,
+        name,
+        description,
+        system_prompt,
+        next_step_prompt,
+        max_steps,
+        current_step,
+        duplicate_threshold
+    ) {}
+};
+
+}
+
+#endif // HUMANUS_AGENT_MANUS_H

agent/planning.cpp

@@ -0,0 +1,233 @@
+#include "planning.h"
+
+namespace humanus {
+
+// Initialize the agent with a default plan ID and validate required tools.
+PlanningAgent* PlanningAgent::initialize_plan_and_verify_tools() {
+    active_plan_id = "plan_" + std::chrono::system_clock::now().time_since_epoch().count();
+
+    if (available_tools.tools_map.find("planning") == available_tools.tools_map.end()) {
+        available_tools.add_tool(std::make_shared<PlanningTool>());
+    }
+
+    return this;
+}
+
+// Decide the next action based on plan status.
+bool PlanningAgent::think() {
+    std::string prompt;
+    if (!active_plan_id.empty()) {
+        auto plan = get_plan();
+        prompt = "CURRENT PLAN STATUS:\n" + plan + "\n\n" + next_step_prompt;
+    } else {
+        prompt = next_step_prompt;
+    }
+    memory->add_message(Message::user_message(prompt));
+    
+    // Get the current step index before thinking
+    current_step_index = _get_current_step_index();
+
+    bool result = ToolCallAgent::think();
+
+    if (result && !tool_calls.empty()) {
+        auto latest_tool_call = tool_calls.back();
+        if (latest_tool_call.function.name != "planning"
+        && !_is_special_tool(latest_tool_call.function.name)
+        && current_step_index >= 0) {
+            step_execution_tracker[latest_tool_call.id] = {
+                {"step_index", current_step_index},
+                {"tool_name", latest_tool_call.function.name},
+                {"status", "pending"} // will be updated after execution
+            };
+        }
+    }
+
+    return result;
+}
+
+// Execute a step and track its completion status.
+std::string PlanningAgent::act() {
+    std::string result = ToolCallAgent::act();
+
+    if (!tool_calls.empty()) {
+        auto latest_tool_call = tool_calls.back();
+
+        // Update the execution status to completed
+        if (step_execution_tracker.find(latest_tool_call.id) != step_execution_tracker.end()) {
+            step_execution_tracker[latest_tool_call.id]["status"] = "completed";
+            step_execution_tracker[latest_tool_call.id]["result"] = result;
+
+            // Update the plan status if this was a non-planning, non-special tool
+            if (latest_tool_call.function.name != "planning"
+            && !_is_special_tool(latest_tool_call.function.name)) {
+                update_plan_status(latest_tool_call.id);
+            }
+        }
+    }
+
+    return result;
+}
+
+// Retrieve the current plan status.
+std::string PlanningAgent::get_plan() {
+    if (active_plan_id.empty()) {
+        return "No active plan. Please create a plan first.";
+    }
+
+    ToolResult result = available_tools.execute(
+        "planning",
+        {{"command", "get"}, {"plan_id", active_plan_id}}
+    );
+
+    return result.to_string();
+}
+
+// Run the agent with an optional initial request.
+std::string PlanningAgent::run(const std::string& request = "") {
+    if (!request.empty()) {
+        create_initial_plan(request);
+    }
+
+    return BaseAgent::run(request);
+}
+
+// Update the current plan progress based on completed tool execution.
+// Only marks a step as completed if the associated tool has been successfully executed.
+void PlanningAgent::update_plan_status(const std::string& tool_call_id) {
+    if (active_plan_id.empty()) {
+        return;
+    }
+
+    if (step_execution_tracker.find(tool_call_id) == step_execution_tracker.end()) {
+        logger->warn("No step tracking found for tool call " + tool_call_id);
+        return;
+    }
+
+    auto tracker = step_execution_tracker[tool_call_id];
+    if (tracker["status"] != "completed") {
+        logger->warn("Tool call " + tool_call_id + " has not completed successfully");
+        return;
+    }
+
+    int step_index = tracker["step_index"];
+
+    try {
+        // Mark the step as completed
+        available_tools.execute(
+            "planning",
+            {{"command", "mark_step"}, {"plan_id", active_plan_id}, {"step_index", step_index}, {"status", "completed"}}
+        );
+        logger->info("Marked step " + std::to_string(step_index) + " as completed in plan " + active_plan_id);
+    } catch (const std::exception& e) {
+        logger->warn("Failed to update plan status: " + std::string(e.what()));
+    }
+}
+
+// Parse the current plan to identify the first non-completed step's index.
+// Returns None if no active step is found.
+int PlanningAgent::_get_current_step_index() {
+    if (active_plan_id.empty()) {
+        return -1;
+    }
+
+    auto plan = get_plan();
+
+    auto splitlines = [](const std::string& s) {
+        std::vector<std::string> lines;
+        std::istringstream iss(s);
+        std::string line;
+        while (std::getline(iss, line)) {
+            lines.push_back(line);
+        }
+        return lines;
+    };
+
+    try {
+        std::vector<std::string> plan_lines = splitlines(plan);
+        int steps_index = -1;
+
+        // Find the index of the "Steps:" line
+        for (size_t i = 0; i < plan_lines.size(); ++i) {
+            if (plan_lines[i].find("Steps:") == 0) {
+                steps_index = i;
+                break;
+            }
+        }
+
+        if (steps_index == -1) {
+            return -1;
+        }
+        
+        // Find the first non-completed step
+        for (size_t i = steps_index + 1; i < plan_lines.size(); ++i) {
+            std::string line = plan_lines[i];
+            if (line.find("[ ]") != std::string::npos || line.find("[→]") != std::string::npos) { // not_started or in_progress
+                // Mark current step as in_progress
+                available_tools.execute(
+                    "planning",
+                    {{"command", "mark_step"}, {"plan_id", active_plan_id}, {"step_index", i}, {"status", "in_progress"}}
+                );
+                return i;
+            }
+        }
+
+        return -1; // # No active step found
+    } catch (const std::exception& e) {
+        logger->warn("Error finding current step index: " + std::string(e.what()));
+        return -1;
+    }
+}
+
+// Create an initial plan based on the request.
+void PlanningAgent::create_initial_plan(const std::string& request) {
+    logger->info("Creating initial plan with ID: " + request);
+
+    std::vector<Message> messages = {
+        Message::user_message(
+            "Analyze the request and create a plan with ID " + active_plan_id + ": " + request
+        )
+    };
+    memory->add_messages(messages);
+    json response = llm->ask_tool(
+        messages,
+        {Message::system_message(system_prompt)},
+        available_tools.to_params(),
+        tool_choice
+    );
+
+    tool_calls = ToolCall::from_json_list(response["tool_calls"]);
+
+    Message assistant_msg = Message::from_tool_calls(
+        tool_calls, response["content"]
+    );
+
+    memory->add_message(assistant_msg);
+
+    bool plan_created = false;
+    for (const ToolCall& tool_call : tool_calls) {
+        if (tool_call.function.name == "planning") {
+            std::string result = execute_tool(tool_call);
+            logger->info("Executed tool " + tool_call.function.name + " with result: " + result);
+
+            // Add tool response to memory
+            Message tool_msg = Message::tool_message(
+                result,
+                tool_call.id,
+                tool_call.function.name
+            );
+            memory->add_message(tool_msg);
+            plan_created = true;
+            break;
+        }
+    }
+
+    if (!plan_created) {
+        logger->warn("No plan created from initial request");
+        Message tool_msg = Message::tool_message(
+            "Error: Parameter `plan_id` is required for command: create"
+        );
+        memory->add_message(tool_msg);
+    }
+}
+
+} // namespace humanus

agent/planning.h

@@ -0,0 +1,72 @@
+#ifndef HUMANUS_AGENT_PLANNING_H
+#define HUMANUS_AGENT_PLANNING_H
+
+#include "toolcall.h"
+#include "../tool/planning.h"
+
+namespace humanus {
+
+/**
+ * An agent that creates and manages plans to solve tasks.
+
+ * This agent uses a planning tool to create and manage structured plans,
+ * and tracks progress through individual steps until task completion.
+*/
+struct PlanningAgent : ToolCallAgent {
+    std::string active_plan_id;
+
+    // Add a dictionary to track the step status for each tool call
+    std::map<std::string, json> step_execution_tracker;
+    int current_step_index;
+
+    PlanningAgent(
+            const ToolCollection& available_tools = ToolCollection(
+                {
+                    std::make_shared<PlanningTool>(),
+                    std::make_shared<Terminate>()
+                }
+            ),
+            const std::string& tool_choice = "auto",
+            const std::set<std::string>& special_tool_names = {"terminate"},
+            const std::string& name = "planning", 
+            const std::string& description = "An agent that creates and manages plans to solve tasks", 
+            const std::string& system_prompt = prompt::planning::PLANNING_SYSTEM_PROMPT,
+            const std::string& next_step_prompt = prompt::planning::NEXT_STEP_PROMPT,
+            int max_steps = 20,
+            int current_step = 0,
+            int duplicate_threshold = 2
+    ) : ToolCallAgent(available_tools, tool_choice, special_tool_names, name, description, system_prompt, next_step_prompt, max_steps, current_step, duplicate_threshold) {
+            current_step_index = -1; // no plan yet
+        }
+
+    // Initialize the agent with a default plan ID and validate required tools.
+    PlanningAgent* initialize_plan_and_verify_tools();
+
+    // Decide the next action based on plan status.
+    bool think() override;
+
+    // Execute a step and track its completion status.
+    std::string act() override;
+
+    // Retrieve the current plan status.
+    std::string get_plan();
+
+    // Run the agent with an optional initial request.
+    std::string run(const std::string& request = "") override;
+
+    // Update the current plan progress based on completed tool execution.
+    // Only marks a step as completed if the associated tool has been successfully executed.
+    void update_plan_status(const std::string& tool_call_id);
+
+    // Parse the current plan to identify the first non-completed step's index.
+    // Returns None if no active step is found.
+    int _get_current_step_index();
+
+    // Create an initial plan based on the request.
+    void create_initial_plan(const std::string& request);
+};
+
+
+} // namespace humanus
+
+#endif // HUMANUS_AGENT_PLANNING_H

agent/react.h

@@ -0,0 +1,36 @@
+#ifndef HUMANUS_AGENT_REACT_H
+#define HUMANUS_AGENT_REACT_H
+
+#include "base.h"
+
+namespace humanus {
+
+struct ReActAgent : BaseAgent {
+    ReActAgent(const std::string& name, 
+            const std::string& description, 
+            const std::string& system_prompt,
+            const std::string& next_step_prompt,
+            int max_steps = 10,
+            int current_step = 0,
+            int duplicate_threshold = 2) : 
+        BaseAgent(name, description, system_prompt, next_step_prompt, max_steps, current_step, duplicate_threshold) {}
+
+    // Process current state and decide next actions using tools
+    virtual bool think() = 0;
+
+    // Execute decided actions
+    virtual std::string act() = 0;
+
+    // Execute a single step: think and act.
+    virtual std::string step() {
+        bool should_act = think();
+        if (!should_act) {
+            return "Thinking complete - no action needed";
+        }
+        return act();
+    }
+};
+
+}
+
+#endif // HUMANUS_AGENT_REACT_H

agent/swe.h

@@ -0,0 +1,53 @@
+#ifndef HUMANUS_AGENT_SWE_H
+#define HUMANUS_AGENT_SWE_H
+
+#include "toolcall.h"
+#include "../tool/tool_collection.h"
+#include "../tool/terminate.h"
+#include "../prompt.h"
+
+namespace humanus {
+
+// An agent that implements the SWEAgent paradigm for executing code and natural conversations.
+struct SweAgent : ToolCallAgent {
+    std::string working_dir;
+    std::shared_ptr<Bash> bash;
+
+    SweAgent(
+        const std::string& working_dir = ".",
+        const std::shared_ptr<Bash>& bash = std::make_shared<Bash>(),
+        const ToolCollection& available_tools = ToolCollection(
+            {
+                std::make_shared<Shell>(),
+                std::make_shared<FileSystem>(),
+                std::make_shared<Terminate>()
+            }
+        ),
+        const std::string& tool_choice = "auto",
+        const std::set<std::string>& special_tool_names = {"terminate"},
+        const std::string& name = "swe", 
+        const std::string& description = "an autonomous AI programmer that interacts directly with the computer to solve tasks.",
+        const std::string& system_prompt = prompt::swe::SYSTEM_PROMPT,
+        const std::string& next_step_prompt = prompt::swe::NEXT_STEP_TEMPLATE,
+        int max_steps = 100,
+        int current_step = 0,
+        int duplicate_threshold = 2
+    ) : ToolCallAgent(available_tools, tool_choice, special_tool_names, name, description, system_prompt, next_step_prompt, max_steps, current_step, duplicate_threshold),
+        bash(bash),
+        working_dir(working_dir) {}
+
+    bool think() override {
+        // Update working directory
+        working_dir = bash->execute("pwd");
+        next_step_prompt = prompt::swe::NEXT_STEP_TEMPLATE;
+        next_step_prompt = next_step_prompt.replace(
+            next_step_prompt.find("{working_dir}"), std::string("{working_dir}").length(), working_dir
+        );
+
+        return ToolCallAgent::think();
+    }
+};
+
+}
+
+#endif // HUMANUS_AGENT_SWE_H

agent/toolcall.cpp

@@ -0,0 +1,172 @@
+#include "toolcall.h"
+
+namespace humanus {
+
+// Process current state and decide next actions using tools
+bool ToolCallAgent::think() {
+    if (!next_step_prompt.empty()) {
+        auto user_msg = Message::user_message(next_step_prompt);
+        memory->add_message(user_msg);
+    }
+
+    // Get response with tool options
+    auto response = llm->ask_tool(
+        memory->messages,
+        std::vector<Message>{Message::system_message(system_prompt)},
+        available_tools.to_params(),
+        tool_choice
+    );
+
+    tool_calls = ToolCall::from_json_list(response["tool_calls"]);
+
+    // Log response info
+    logger->info("✨ {self.name}'s thoughts:" + response["content"].dump());
+    logger->info(
+        "🛠️ " + name + " selected " + std::to_string(tool_calls.size()) + " tool(s) to use"
+    );
+    if (tool_calls.size() > 0) {
+        std::string tools_str;
+        for (const auto& tool_call : tool_calls) {
+            tools_str += tool_call.function.name + " ";
+        }
+        logger->info(
+            "🧰 Tools being prepared: " + tools_str
+        );
+    }
+
+    try {
+        // Handle different tool_choices modes
+        if (tool_choice == "none") {
+            if (tool_calls.size() > 0) {
+                logger->warn("🤔 Hmm, " + name + "tried to use tools when they weren't available!");
+            }
+            if (!response["content"].empty()) {
+                memory->add_message(Message::assistant_message(response["content"]));
+                return true;
+            }
+            return false;
+        } 
+
+        // Create and add assistant message
+        auto assistant_msg = tool_calls.size() > 0 ? 
+                            Message::from_tool_calls(tool_calls, response["content"]) :
+                            Message::assistant_message(response["content"]);
+        memory->add_message(assistant_msg);
+
+        if (tool_choice == "required" && tool_calls.empty()) {
+            return true; // will be handled in act()
+        }
+
+        // For 'auto' mode, continue with content if no commands but content exists
+        if (tool_choice == "auto" && !tool_calls.empty()) {
+            return !response["content"].is_null() && !response["content"].empty();
+        }
+
+        return !tool_calls.empty();
+    } catch (const std::exception& e) {
+        logger->error("🚨 Oops! The " + name + "'s thinking process hit a snag: " + std::string(e.what()));
+        memory->add_message(Message::assistant_message(
+            "Error encountered while processing: " + std::string(e.what())
+        ));
+        return false;
+    }
+}
+
+// Execute tool calls and handle their results
+std::string ToolCallAgent::act() {
+    if (tool_calls.empty()) {
+        if (tool_choice == "required") {
+            throw std::runtime_error(TOOL_CALL_REQUIRED);
+        }
+
+        // Return last message content if no tool calls
+        return memory->messages.back().content.empty() ? "No content or commands to execute" : memory->messages.back().content.dump();
+    }
+
+    std::vector<std::string> results;
+    for (const auto& tool_call : tool_calls) {
+        auto result = std::async(std::launch::async, [this, tool_call]() {
+            return execute_tool(tool_call);
+        });
+        logger->info(
+            "🎯 Tool '" + tool_call.function.name + "' ompleted its mission! Result: " + result.get()
+        );
+
+        // Add tool response to memory
+        Message tool_msg = Message::tool_message(
+            result.get(), tool_call.id, tool_call.function.name
+        );
+        memory->add_message(tool_msg);
+        results.push_back(result.get());
+    }
+
+    std::string result_str;
+    for (const auto& result : results) {
+        result_str += result + "\n\n";
+    }
+
+    return result_str;
+}
+
+std::string ToolCallAgent::execute_tool(ToolCall tool_call) {
+    if (tool_call.empty() || tool_call.function.empty() || tool_call.function.name.empty()) {
+        return "Error: Invalid command format";
+    }
+
+    std::string name = tool_call.function.name;
+    if (available_tools.tools_map.find(name) == available_tools.tools_map.end()) {
+        return "Error: Unknown tool '" + name + "'";
+    }
+
+    try {
+        // Parse arguments
+        json args = tool_call.function.arguments;
+
+        // Execute the tool
+        logger->info("🔧 Activating tool: '" + name + "'...");
+        ToolResult result = available_tools.execute(name, args);
+
+        // Format result for display
+        auto observation = result.to_string().empty() ?
+                            "Cmd `" + name + "` completed with no output" :
+                            "Observed output of cmd `" + name + "` executed:\n" + result.to_string();
+
+        // Handle special tools like `finish`
+        _handle_special_tool(name, result);
+
+        return observation;
+    } catch (const json::exception& e) {
+        std::string error_msg = "Error parsing arguments for " + name + ": Invalid JSON format";
+        logger->error(
+            "📝 Oops! The arguments for '" + name + "' don't make sense - invalid JSON"
+        );
+        return "Error: " + error_msg;
+    } catch (const std::exception& e) {
+        std::string error_msg = "⚠️ Tool '" + name + "' encountered a problem: " + std::string(e.what());
+        logger->error(error_msg);
+        return "Error: " + error_msg;
+    }
+}
+
+// Handle special tool execution and state changes
+void ToolCallAgent::_handle_special_tool(const std::string& name, const ToolResult& result, const json& kwargs) {
+    if (!_is_special_tool(name)) {
+        return;
+    }
+
+    if (_should_finish_execution(name, result, kwargs)) {
+        logger->info("🏁 Special tool '" + name + "' has completed the task!");
+        state = AgentState::FINISHED;
+    }
+}
+
+// Determine if tool execution should finish the agent
+bool ToolCallAgent::_should_finish_execution(const std::string& name, const ToolResult& result, const json& kwargs) {
+    return true; // currently, all special tools (terminate) finish the agent
+}
+
+bool ToolCallAgent::_is_special_tool(const std::string& name) {
+    return special_tool_names.find(name) != special_tool_names.end();
+}
+    
+}

agent/toolcall.h

@@ -0,0 +1,62 @@
+#ifndef HUMANUS_AGENT_TOOLCALL_H
+#define HUMANUS_AGENT_TOOLCALL_H
+
+#include "react.h"
+#include "../prompt.h"
+#include "../tool/tool_collection.h"
+#include "../tool/create_chat_completion.h"
+#include "../tool/terminate.h"
+
+namespace humanus {
+
+const char* TOOL_CALL_REQUIRED = "Tool calls required but none provided";
+
+// Base agent class for handling tool/function calls with enhanced abstraction
+struct ToolCallAgent : ReActAgent {
+    std::vector<ToolCall> tool_calls;
+    ToolCollection available_tools;
+    std::string tool_choice;
+    std::set<std::string> special_tool_names;
+
+    ToolCallAgent(
+        const ToolCollection& available_tools = ToolCollection(
+            {
+                std::make_shared<CreateChatCompletion>(),
+                std::make_shared<Terminate>()
+            }
+        ),
+        const std::string& tool_choice = "auto",
+        const std::set<std::string>& special_tool_names = {"terminate"},
+        const std::string& name = "toolcall", 
+        const std::string& description = "an agent that can execute tool calls.", 
+        const std::string& system_prompt = prompt::toolcall::SYSTEM_PROMPT,
+        const std::string& next_step_prompt = prompt::toolcall::NEXT_STEP_PROMPT,
+        int max_steps = 30,
+        int current_step = 0,
+        int duplicate_threshold = 2
+    ) : ReActAgent(name, description, system_prompt, next_step_prompt, max_steps, current_step, duplicate_threshold),
+        available_tools(available_tools),
+        tool_choice(tool_choice),
+        special_tool_names(special_tool_names) {}
+
+    // Process current state and decide next actions using tools
+    bool think() override;
+
+    // Execute tool calls and handle their results
+    std::string act() override;
+
+    std::string execute_tool(ToolCall tool_call);
+
+    // Handle special tool execution and state changes
+    void _handle_special_tool(const std::string& name, const ToolResult& result, const json& kwargs = {});
+
+    // Determine if tool execution should finish the agent
+    static bool _should_finish_execution(const std::string& name, const ToolResult& result, const json& kwargs = {});
+
+    bool _is_special_tool(const std::string& name);
+    
+};
+
+}
+
+#endif // HUMANUS_AGENT_TOOLCALL_H

config.cpp

@@ -0,0 +1,72 @@
+#include "config.h"
+#include "logger.h"
+#include "toml.hpp"
+#include <iostream>
+#include <filesystem>
+
+namespace humanus {
+
+// 初始化静态成员
+Config* Config::_instance = nullptr;
+std::mutex Config::_mutex;
+
+// 全局配置实例
+Config& config = Config::getInstance();
+
+void Config::_load_initial_config() {
+    try {
+        auto config_path = _get_config_path();
+        std::cout << "加载配置文件: " << config_path.string() << std::endl;
+        
+        auto data = toml::parse_file(config_path.string());
+        
+        // 解析LLM设置
+        if (data.contains("llm") && data["llm"].is_table()) {
+            auto& llm_table = data["llm"].as_table();
+            for (const auto& [name, settings] : llm_table) {
+                LLMSettings llm_settings;
+                
+                if (settings.contains("model") && settings["model"].is_string()) {
+                    llm_settings.model = settings["model"].as_string();
+                }
+                
+                if (settings.contains("api_key") && settings["api_key"].is_string()) {
+                    llm_settings.api_key = settings["api_key"].as_string();
+                }
+                
+                if (settings.contains("base_url") && settings["base_url"].is_string()) {
+                    llm_settings.base_url = settings["base_url"].as_string();
+                }
+
+                if (settings.contains("end_point") && settings["end_point"].is_string()) {
+                    llm_settings.end_point = settings["end_point"].as_string();
+                }
+                
+                if (settings.contains("max_tokens") && settings["max_tokens"].is_integer()) {
+                    llm_settings.max_tokens = settings["max_tokens"].as_integer();
+                }
+                
+                if (settings.contains("temperature") && settings["temperature"].is_floating()) {
+                    llm_settings.temperature = settings["temperature"].as_floating();
+                }
+                
+                _config.llm[name] = llm_settings;
+            }
+        }
+        
+    } catch (const std::exception& e) {
+        std::cerr << "加载配置文件失败: " << e.what() << std::endl;
+        // 设置默认配置
+        LLMSettings default_settings;
+        default_settings.model = "gpt-3.5-turbo";
+        default_settings.api_key = "sk-";
+        default_settings.base_url = "https://api.openai.com";
+        default_settings.end_point = "/v1/chat/completions";
+        default_settings.max_tokens = 4096;
+        default_settings.temperature = 1.0;
+        
+        _config.llm["default"] = default_settings;
+    }
+}
+
+} // namespace humanus

config.h

@@ -0,0 +1,154 @@
+#ifndef HUMANUS_CONFIG_H
+#define HUMANUS_CONFIG_H
+
+#include <string>
+#include <map>
+#include <fstream>
+#include <sstream>
+#include <mutex>
+#include <filesystem>
+#include <memory>
+
+#include "schema.h"
+
+namespace humanus {
+
+static std::filesystem::path get_project_root() {
+    // 获取项目根目录
+    return std::filesystem::path(__FILE__).parent_path().parent_path();
+}
+
+const std::filesystem::path PROJECT_ROOT = get_project_root();
+const std::filesystem::path WORKSPACE_ROOT = PROJECT_ROOT / "workspace";
+
+/**
+ * @brief LLM设置结构体
+ */
+struct LLMSettings {
+    std::string model;
+    std::string api_key;
+    std::string base_url;
+    std::string end_point;
+    int max_tokens;
+    double temperature;
+
+    LLMSettings(
+        std::string model = "", 
+        std::string api_key = "", 
+        std::string base_url = "", 
+        std::string end_point = "/v1/chat/completions",
+        int max_tokens = 4096, 
+        double temperature = 1.0
+    ) : model(model), api_key(api_key), base_url(base_url), end_point(end_point),
+        max_tokens(max_tokens), temperature(temperature) {}
+        
+    json to_json() const {
+        json j;
+        j["model"] = model;
+        j["api_key"] = api_key;
+        j["base_url"] = base_url;
+        j["end_point"] = end_point;
+        j["max_tokens"] = max_tokens;
+        j["temperature"] = temperature;
+        return j;
+    }
+};
+
+/**
+ * @brief 应用配置结构体
+ */
+struct AppConfig {
+    std::map<std::string, LLMSettings> llm;
+    
+    json to_json() const {
+        json j;
+        json llm_json;
+        for (const auto& [name, settings] : llm) {
+            llm_json[name] = settings.to_json();
+        }
+        j["llm"] = llm_json;
+        return j;
+    }
+};
+
+/**
+ * @class Config
+ * @brief 配置单例类，用于读取TOML格式的配置文件
+ */
+class Config {
+private:
+    static Config* _instance;
+    static std::mutex _mutex;
+    bool _initialized = false;
+    AppConfig _config;
+    
+    // 私有构造函数
+    Config() {
+        _load_initial_config();
+        _initialized = true;
+    }
+    
+    // 禁止拷贝和赋值
+    Config(const Config&) = delete;
+    Config& operator=(const Config&) = delete;
+    
+    /**
+     * @brief 获取配置文件路径
+     * @return 配置文件路径
+     */
+    static std::filesystem::path _get_config_path() {
+        auto root = PROJECT_ROOT;
+        auto config_path = root / "config" / "config.toml";
+        if (std::filesystem::exists(config_path)) {
+            return config_path;
+        }
+        auto example_path = root / "config" / "config.example.toml";
+        if (std::filesystem::exists(example_path)) {
+            return example_path;
+        }
+        throw std::runtime_error("无法找到配置文件");
+    }
+    
+    /**
+     * @brief 加载配置文件
+     */
+    void _load_initial_config();
+
+public:
+    /**
+     * @brief 获取单例实例
+     * @return 配置实例
+     */
+    static Config& getInstance() {
+        if (_instance == nullptr) {
+            std::lock_guard<std::mutex> lock(_mutex);
+            if (_instance == nullptr) {
+                _instance = new Config();
+            }
+        }
+        return *_instance;
+    }
+    
+    /**
+     * @brief 获取LLM设置
+     * @return LLM设置映射
+     */
+    const std::map<std::string, LLMSettings>& getLLMSettings() const {
+        return _config.llm;
+    }
+    
+    /**
+     * @brief 获取应用配置
+     * @return 应用配置
+     */
+    const AppConfig& getConfig() const {
+        return _config;
+    }
+};
+
+// 全局配置实例
+extern Config& config;
+
+} // namespace humanus
+
+#endif // HUMANUS_CONFIG_H 

config/config.toml

@@ -0,0 +1,5 @@
+[llm]
+model = "anthropic/claude-3.7-sonnet"
+base_url = "https://openrouter.ai/api/v1"
+api_key = "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"
+max_tokens = 4096

config/config_mcp.toml

@@ -0,0 +1,22 @@
+[python_execute]
+type = "sse"
+host = "localhost"
+port = 8818
+sse_endpoint = "/sse"
+
+[puppeteer]
+type = "command"
+command = "npx"
+args = ["-y", "@modelcontextprotocol/server-puppeteer"]
+
+[filesystem]
+type = "command"
+command = "npx"
+args = ["-y",
+        "@modelcontextprotocol/server-filesystem",
+        "/Users/username/Desktop",
+        "/path/to/other/allowed/dir"]
+
+[shell]
+type = "command"
+command = "uvx mcp-shell-server"

flow/base.h

@@ -0,0 +1,50 @@
+#ifndef HUMANUS_FLOW_BASE_H
+#define HUMANUS_FLOW_BASE_H
+
+#include "../agent/base.h"
+
+namespace humanus {
+
+enum FlowType {
+    PLANING = 0
+};
+
+const std::map<FlowType, std::string> FLOW_TYPE_MAP = {
+    {PLANING, "planning"}
+};
+
+// Base class for execution flows supporting multiple agents
+struct BaseFlow {
+    std::map<std::string, std::shared_ptr<BaseAgent>> agents;
+    std::vector<std::shared_ptr<BaseTool>> tools;
+    std::string primary_agent_key;
+
+    BaseFlow(const std::map<std::string, std::shared_ptr<BaseAgent>>& agents = {}, const std::vector<std::shared_ptr<BaseTool>>& tools = {}, const std::string& primary_agent_key = "") : agents(agents), tools(tools), primary_agent_key(primary_agent_key) {
+        // If primary agent not specified, use first agent
+        if (primary_agent_key.empty() && !agents.empty()) {
+            primary_agent_key = agents.begin()->first;
+        }
+    }
+
+    // Get the primary agent for the flow
+    std::shared_ptr<BaseAgent> primary_agent() const {
+        return agents.at(primary_agent_key);
+    }
+
+    // Get a specific agent by key
+    std::shared_ptr<BaseAgent> get_agent(const std::string& key) const {
+        return agents.at(key);
+    }
+
+    // Add a new agent to the flow
+    void add_agent(const std::string& key, const std::shared_ptr<BaseAgent>& agent) {
+        agents[key] = agent;
+    }
+
+    // Execute the flow with the given input
+    virtual std::string execute(const std::string& input) = 0;
+};
+
+}
+
+#endif // HUMANUS_FLOW_BASE_H

flow/flow_factory.h

@@ -0,0 +1,23 @@
+#ifndef HUMANUS_FLOW_FACTORY_H
+#define HUMANUS_FLOW_FACTORY_H
+
+#include "base.h"
+#include "../agent/base.h"
+#include "flow_planning.h"
+
+namespace humanus {
+
+// Factory for creating different types of flows with support for multiple agents
+struct FlowFactory {
+    static BaseFlow create_flow(FlowType flow_type, std::map<std::string, std::shared_ptr<BaseAgent>> agents, std::vector<std::shared_ptr<BaseTool>> tools, std::string primary_agent_key) {
+        switch (flow_type) {
+            case FlowType::PLANNING:
+                return std::make_shared<PlanningFlow>(agents, tools, primary_agent_key);
+            default:
+                throw std::invalid_argument("Unknown flow type: " + std::to_string(static_cast<int>(flow_type)));
+        }
+    }
+};
+
+}
+#endif // HUMANUS_FLOW_FACTORY_H

flow/flow_planning.cpp

@@ -0,0 +1,407 @@
+#include "flow_planning.h"
+
+namespace humanus {
+
+// Get an appropriate executor agent for the current step.
+// Can be extended to select agents based on step type/requirements.
+std::shared_ptr<BaseAgent> PlanningFlow::get_executor(const std::string& step_type = "") const {
+    // If step type is provided and matches an agent key, use that agent
+    if (!step_type.empty() && agents.find(step_type) != agents.end()) {
+        return agents[step_type];
+    }
+
+    // Otherwise use the first available executor or fall back to primary agent
+    for (const auto& key : executor_keys) {
+        if (agents.find(key) != agents.end()) {
+            return agents[key];
+        }
+    }
+
+    // Fallback to primary agent
+    return primary_agent();
+}
+
+// Execute the planning flow with agents.
+std::string PlanningFlow::execute(const std::string& input) {
+    try {
+        if (agents.find(primary_agent_key) == agents.end()) {
+            throw std::runtime_error("No primary agent available");
+        }
+
+        // Create initial plan if input provided
+        if (!input.empty()) {
+            _create_initial_plan(input);
+
+            // Verify plan was created successfully
+            if (planning_tool.plans.find(active_plan_id) == planning_tool.plans.end()) {
+                logger->error("Plan creation failed. Plan ID " + active_plan_id + " not found in planning tool.");
+                return "Failed to create plan for: " + input;
+            }
+        }
+
+        std::string result = "";
+        while (true) {
+            // Get current step to execute
+            mcp::json step_info;
+            _get_current_step_info(current_step_index, step_info);
+
+            // Exit if no more steps or plan completed
+            if (current_step_index < 0) {
+                result += _finalize_plan();
+                break;
+            }
+
+            // Execute current step with appropriate agent
+            std::string step_type = step_info.value("type", "");
+            auto executor = get_executor(step_type);
+            std::string step_result = _execute_step(executor, step_info);
+            result += step_result + "\n";
+
+            // Check if agent wants to terminate
+            if (executor->state == AgentState::TERMINATED) {
+                break;
+            }
+        }
+
+        return result;
+    } catch (const std::exception& e) {
+        LOG_ERROR("Error executing planning flow: " + std::string(e.what()));
+        return "Execution failed: " + std::string(e.what());
+    }
+}
+
+// Create an initial plan based on the request using the flow's LLM and PlanningTool.
+void PlanningFlow::_create_initial_plan(const std::string& request) {
+    logger->info("Creating initial plan with ID: " + active_plan_id);
+
+    // Create a system message for plan creation
+    Message system_message = Message::system_message(
+        "You are a planning assistant. Your task is to create a detailed plan with clear steps."
+    );
+
+    // Create a user message with the request
+    Message user_message = Message::user_message(
+        "Create a detailed plan to accomplish this task: " + request
+    );
+
+    // Call LLM with PlanningTool
+    auto response = llm->ask_tool(
+        {user_message},
+        {system_message},
+        {planning_tool.to_param()},
+        "required"
+    );
+
+    // Process tool calls if present
+    if (response.contains("tool_calls") && !response["tool_calls"].empty()) {
+        tool_calls = ToolCall::from_json_list(response["tool_calls"]);
+
+        for (const auto& tool_call : tool_calls) {
+            // Parse the arguments
+            auto args = tool_call.function.arguments;
+            if (args.is_string()) {
+                try {
+                    args = json::parse(args);
+                } catch (...) {
+                    logger->error("Failed to parse tool arguments: " + args.dump());
+                    continue;
+                }
+            }
+
+            // Ensure plan_id is set correctly and execute the tool
+            args["plan_id"] = active_plan_id;
+
+            // Execute the tool via ToolCollection instead of directly
+            auto result = planning_tool.execute(tool_call.function.name, args);
+
+            logger->info("Plan creation result: " + result.to_string());
+            return;
+        }
+    }
+
+    // If execution reached here, create a default plan
+    logger->warn("Creating default plan");
+
+    // Create default plan using the ToolCollection
+    planning_tool.execute({
+        {"command", "create"},
+        {"plan_id", active_plan_id},
+        {"title", request.substr(0, std::min(50, static_cast<int>(request.size()))) + (request.size() > 50 ? "..." : "")},
+        {"steps", {"Analyze request", "Execute task", "Verify results"}}
+    });
+}
+
+// Parse the current plan to identify the first non-completed step's index and info.
+// Returns (None, None) if no active step is found.
+void PlanningFlow::_get_current_step_info(int& current_step_index, mcp::json& step_info) {
+    if (active_plan_id.empty() || planning_tool.plans.find(active_plan_id) == planning_tool.plans.end()) {
+        logger->error("Plan with ID " + active_plan_id + " not found");
+        current_step_index = -1;
+        step_info = mcp::json::object();
+        return;
+    }
+
+    try {
+        // Direct access to plan data from planning tool storage
+        mcp::json& plan_data = planning_tool.plans[active_plan_id];
+        mcp::json steps = plan_data.value("steps", mcp::json::array());
+        mcp::json step_status = plan_data.value("status", mcp::json::array());
+
+        // Find first non-completed step
+        for (size_t i = 0; i < steps.size(); ++i) {
+            const auto& step = steps[i];
+            std::string step_status;
+
+            if (i >= step_status.size()) {
+                step_status = "not_started";
+            } else {
+                step_status = step_status[i];
+            }
+            
+            if (step_status == "not_started" || step_status == "in_progress") {
+                // Extract step type/category if available
+                step_info = {
+                    {"type", step},
+                }
+            }
+
+            // Try to extract step type from the text (e.g., [SEARCH] or [CODE])
+            std::regex step_regex("\\[([A-Z_]+)\\]");
+            std::smatch match;
+            if (std::regex_search(step, match, step_regex)) {
+                step_info["type"] = match[1].str(); // to_lower?
+            }
+
+            // Mark current step as in_progress
+            try {
+                planning_tool.execute({
+                    {"command", "mark_step"},
+                    {"plan_id", active_plan_id},
+                    {"step_index", i},
+                    {"status", "in_progress"}
+                });
+            } catch (const std::exception& e) {
+                logger->error("Error marking step as in_progress: " + std::string(e.what()));
+                // Update step status directly if needed
+                if (i < step_status.size()) {
+                    step_status[i] = "in_progress";
+                } else {
+                    while (i > step_status.size()) {
+                        step_status.push_back("not_started");
+                    }
+                    step_status.push_back("in_progress");
+                }
+
+                plan_data["step_statuses"] = step_statuses;
+            }
+
+            current_step_index = i;
+            step_info = step;
+            return;
+        }
+        current_step_index = -1;
+        step_info = mcp::json::object(); // No active step found
+    } catch (const std::exception& e) {
+        logger->error("Error finding current step index: " + std::string(e.what()));
+        current_step_index = -1;
+        step_info = mcp::json::object();
+    }
+}
+
+// Execute the current step with the specified agent using agent.run().
+std::string PlanningFlow::_execute_step(const std::shared_ptr<BaseAgent>& executor, const mcp::json& step_info) {
+    // Prepare context for the agent with current plan status
+    mcp::json plan_status = _get_plan_status();
+    std::string step_text = step_info.value("text", "Step " + std::to_string(current_step_index));
+
+    // Create a prompt for the agent to execute the current step
+    std::string step_prompt;
+    step_prompt += "\n\nCURRENT PLAN STATUS:\n";
+    step_prompt += plan_status.dump(4);
+    step_prompt += "\n\nYOUR CURRENT TASK:\n";
+    step_prompt += "You are now working on step " + std::to_string(current_step_index) + ": \"" + step_text + "\"\n";
+    step_prompt += "Please execute this step using the appropriate tools. When you're done, provide a summary of what you accomplished.";
+
+    // Use agent.run() to execute the step
+    try {
+        std::string result = executor->run(step_prompt);
+
+        // Mark the step as completed after successful execution
+        _mark_step_completed();
+
+        return step_result;
+    } catch (const std::exception& e) {
+        LOG_ERROR("Error executing step " + std::to_string(current_step_index) + ": " + std::string(e.what()));
+        return "Error executing step " + std::to_string(current_step_index) + ": " + std::string(e.what());
+    }
+}
+
+// Mark the current step as completed.
+void PlanningFlow::_mark_step_completed() {
+    if (current_step_index < 0) {
+        return;
+    }
+
+    try {
+        // Mark the step as completed
+        planning_tool.execute({
+            {"command", "mark_step"},
+            {"plan_id", active_plan_id},
+            {"step_index", current_step_index},
+            {"status", "completed"}
+        });
+        logger->info(
+            "Marked step " + std::to_string(current_step_index) + " as completed in plan " + active_plan_id
+        );
+    } catch (const std::exception& e) {
+        LOG_WARN("Failed to update plan status: " + std::string(e.what()));
+        // Update step status directly in planning tool storage
+        if (planning_tool.plans.find(active_plan_id) != planning_tool.plans.end()) {
+            mcp::json& plan_data = planning_tool.plans[active_plan_id];
+            mcp::json step_statuses = plan_data.value("step_statuses", mcp::json::array());
+
+            // Ensure the step_statuses list is long enough
+            while (current_step_index >= step_statuses.size()) {
+                step_statuses.push_back("not_started");
+            }
+
+            // Update the status
+            step_statuses[current_step_index] = "completed";
+            plan_data["step_statuses"] = step_statuses;
+        }
+    }
+}
+
+// Get the current plan as formatted text.
+std::string PlanningFlow::_get_plan_text() {
+    try {
+        auto result = planning_tool.execute({
+            {"command", "get"},
+            {"plan_id", active_plan_id}
+        });
+
+        return result.to_string();
+    } catch (const std::exception& e) {
+        LOG_ERROR("Error getting plan: " + std::string(e.what()));
+        return _generate_plan_text_from_storage();
+    }
+}
+
+// Generate plan text directly from storage if the planning tool fails.
+std::string PlanningFlow::_generate_plan_text_from_storage() {
+    try {
+        if (planning_tool.plans.find(active_plan_id) == planning_tool.plans.end()) {
+            return "Error: Plan with ID " + active_plan_id + " not found";
+        }
+
+        mcp::json& plan_data = planning_tool.plans[active_plan_id];
+        auto title = plan_data.value("title", "");
+        auto steps = plan_data.value("steps", mcp::json::array());
+        auto step_statuses = plan_data.value("step_statuses", mcp::json::array());
+        auto step_notes = plan_data.value("step_notes", mcp::json::array());
+
+        // Ensure step_statuses and step_notes match the number of steps
+        while (step_statuses.size() < steps.size()) {
+            step_statuses.push_back("not_started");
+        }
+        while (step_notes.size() < steps.size()) {
+            step_notes.push_back("");
+        }
+        
+        // Count steps by status
+        mcp::json status_counts = {
+            {"completed", 0},
+            {"in_progress", 0},
+            {"blocked", 0},
+            {"not_started", 0}
+        };
+
+        for (const auto& status : step_statuses) {
+            if (status_counts.contains(status)) {
+                status_counts[status]++;
+            }
+        }
+
+        int completed = status_counts["completed"];
+        int total = steps.size();
+        double progress = total > 0 ? (static_cast<double>(completed) / total) * 100.0 : 0.0;
+
+        std::stringstream plan_text_ss;
+        plan_text_ss << "Plan: " << title << "(ID: " << active_plan_id << ")\n";
+        plan_text_ss << std::string(plan_text_ss.str().size(), '=') << "\n\n";
+
+        plan_text_ss << "Total steps: " << completed << "/" << total << " steps completed (" << std::fixed << std::setprecision(1) << progress << "%)\n";
+        plan_text_ss << "Status: " << status_counts["completed"].get<int>() << " completed, " << status_counts["in_progress"].get<int>() << " in progress, " 
+                        << status_counts["blocked"].get<int>() << " blocked, " << status_counts["not_started"].get<int>() << " not started\n\n";
+        plan_text_ss << "Steps:\n";
+
+        for (size_t i = 0; i < steps.size(); ++i) {
+            auto step = steps[i];
+            auto status = step_statuses[i];
+            auto notes = step_notes[i];
+
+            std::string status_mark;
+
+            if (status == "completed") {
+                status_mark = "[✓]"; 
+            } else if (status == "in_progress") {
+                status_mark = "[→]";
+            } else if (status == "blocked") {
+                status_mark = "[!]";
+            } else if (status == "not_started") {
+                status_mark = "[ ]";
+            }
+
+            plan_text_ss << i << ". " << status_mark << " " << step << "\n";
+            if (!notes.empty()) {
+                plan_text_ss << "    Notes: " << notes << "\n";
+            }
+        }
+
+        return plan_text_ss.str();
+    } catch (const std::exception& e) {
+        logger->error("Error generating plan text from storage: " + std::string(e.what()));
+        return "Error: Unable to retrieve plan with ID " + active_plan_id;
+    }
+}
+
+// Finalize the plan and provide a summary using the flow's LLM directly
+std::string PlanningFlow::_finalize_plan() {
+    std::string plan_text = _get_plan_text();
+
+    // Create a summary using the flow's LLM directly
+    try {
+        Message system_message = Message::system_message(
+            "You are a planning assistant. Your task is to summarize the completed plan."
+        );
+
+        Message user_message = Message::user_message(
+            "The plan has been completed. Here is the final plan status:\n\n" + plan_text + "\n\n" +
+            "Please provide a summary of what was accomplished and any final thoughts."
+        );
+
+        auto response = llm->ask(
+            {user_message},
+            {system_message}
+        );
+
+        return response.to_string();
+    } catch (const std::exception& e) {
+        LOG_ERROR("Error finalizing plan with LLM: " + std::string(e.what()));
+
+        // Fallback to using an agent for the summary
+        try {
+            auto agent = primary_agent();
+            std::string summary_prompt = "\nThe plan has been completed. Here is the final plan status:\n\n";
+            summary_prompt += plan_text + "\n\n";
+            summary_prompt += "Please provide a summary of what was accomplished and any final thoughts\n";
+            std::string summary = agent->run(summary_prompt);
+            return "Plan completed:\n\n" + summary;
+        } catch (const std::exception& e2) {
+            LOG_ERROR("Error finalizing plan with agent: " + std::string(e2.what()));
+            return "Plan completed. Error generating summary.";
+        }
+    }
+}
+
+}

flow/flow_planning.h

@@ -0,0 +1,73 @@
+#ifndef HUMANUS_FLOW_PLANNING_H
+#define HUMANUS_FLOW_PLANNING_H
+
+#include "base.h"
+#include "../agent/base.h"
+#include "../llm.h"
+#include "../logger.h"
+#include "../schema.h"
+#include "../tool/planning.h"
+#include <regex>
+
+namespace humanus {
+
+// A flow that manages planning and execution of tasks using agents.
+struct FlowPlanning : public BaseFlow {
+    std::shared_ptr<LLM> llm;
+    PlanningTool planning_tool;
+    std::vector<std::string> executor_keys;
+    std::string active_plan_id;
+    int current_step_index = -1;
+
+    FlowPlanning(const std::shared_ptr<LLM>& llm,
+                const PlanningTool& planning_tool = PlanningTool(),
+                const std::vector<std::string>& executor_keys = {},
+                const std::string& active_plan_id = "",
+                const std::map<std::string, std::shared_ptr<BaseAgent>>& agents = {},
+                const std::vector<std::shared_ptr<BaseTool>>& tools = {},
+                const std::string& primary_agent_key = "")
+                : BaseFlow(agents, tools, primary_agent_key),
+                  llm(llm),
+                  planning_tool(planning_tool),
+                  executor_keys(executor_keys),
+                  active_plan_id(active_plan_id) {
+        if (executor_keys.empty()) {
+            for (const auto& [key, agent] : agents) {
+                executor_keys.push_back(key);
+            }
+        }
+    }
+    
+    // Get an appropriate executor agent for the current step.
+    // Can be extended to select agents based on step type/requirements.
+    std::shared_ptr<BaseAgent> get_executor(const std::string& step_type = "") const;
+
+    // Execute the planning flow with agents.
+    std::string execute(const std::string& input) override;
+
+    // Create an initial plan based on the request using the flow's LLM and PlanningTool.
+    void _create_initial_plan(const std::string& request);
+
+    // Parse the current plan to identify the first non-completed step's index and info.
+    // Returns (None, None) if no active step is found.
+    void _get_current_step_info(int& current_step_index, mcp::json& step_info);
+
+    // Execute the current step with the specified agent using agent.run().
+    std::string _execute_step(const std::shared_ptr<BaseAgent>& executor, const mcp::json& step_info);
+
+    // Mark the current step as completed.
+    void _mark_step_completed();
+
+    // Get the current plan as formatted text.
+    std::string _get_plan_text();
+    
+    // Generate plan text directly from storage if the planning tool fails.
+    std::string _generate_plan_text_from_storage();
+
+    // Finalize the plan and provide a summary using the flow's LLM directly
+    std::string _finalize_plan();
+};
+
+}
+
+#endif // HUMANUS_FLOW_PLANNING_H

llm.h

@@ -0,0 +1,263 @@
+#ifndef HUMANUS_LLM_H
+#define HUMANUS_LLM_H
+
+#include "config.h"
+#include "logger.h"
+#include "schema.h"
+#include "mcp/common/httplib.h"
+#include <map>
+#include <string>
+#include <memory>
+#include <vector>
+#include <functional>
+#include <stdexcept>
+#include <future>
+
+namespace humanus {
+
+class LLM {
+private:
+    static std::map<std::string, std::shared_ptr<LLM>> _instances;
+    
+    std::string model;
+    std::string api_key;
+    int max_tokens;
+    double temperature;
+
+    std::unique_ptr<httplib::Client> client_ = nullptr;
+    int max_retries = 3;
+
+    LLMSettings llm_config_;
+    
+    // 私有构造函数，防止直接创建实例
+    LLM(const std::string& config_name, const LLMSettings llm_config) : llm_config_(llm_config) {
+        model = llm_config.model;
+        api_key = llm_config.api_key;
+        max_tokens = llm_config.max_tokens;
+        temperature = llm_config.temperature;
+        client_ = std::make_unique<httplib::Client>(llm_config.base_url);
+    }
+
+public:
+    // 单例模式获取实例
+    static std::shared_ptr<LLM> get_instance(const std::string& config_name = "default", const LLMSettings llm_config = LLMSettings()) {
+        if (_instances.find(config_name) == _instances.end()) {
+            _instances[config_name] = std::make_shared<LLM>(config_name, llm_config);
+        }
+        return _instances[config_name];
+    }
+    
+    /**
+     * @brief 格式化消息列表为LLM可接受的格式
+     * @param messages Message对象消息列表
+     * @return 格式化后的消息列表
+     * @throws std::invalid_argument 如果消息格式无效或缺少必要字段
+     * @throws std::runtime_error 如果消息类型不支持
+     */
+    static std::vector<json> format_messages(const std::vector<Message>& messages) {
+        std::vector<json> formatted_messages;
+
+        for (const auto& message : messages) {
+            formatted_messages.push_back(message.to_json());
+        }
+
+        for (const auto& message : formatted_messages) {
+            if (message["role"] != "user" && message["role"] != "assistant" && message["role"] != "system" && message["role"] != "tool") {
+                throw std::invalid_argument("Invalid role: " + message["role"]);
+            }
+            if (!message.contains("content") && !message.contains("tool_calls")) {
+                throw std::invalid_argument("Message must contain either 'content' or 'tool_calls'");
+            }
+        }
+
+        return formatted_messages;
+    }
+
+    /**
+     * @brief 格式化消息列表为LLM可接受的格式
+     * @param messages json对象消息列表
+     * @return 格式化后的消息列表
+     * @throws std::invalid_argument 如果消息格式无效或缺少必要字段
+     * @throws std::runtime_error 如果消息类型不支持
+     */
+    static std::vector<json> format_messages(const std::vector<json>& messages) {
+        std::vector<json> formatted_messages;
+
+        for (const auto& message : messages) {
+            if (!message.contains("role")) {
+                throw std::invalid_argument("消息缺少必要字段: role");
+            }
+            formatted_messages.push_back(message);
+        }
+
+        for (const auto& message : formatted_messages) {
+            if (message["role"] != "user" && message["role"] != "assistant" && message["role"] != "system" && message["role"] != "tool") {
+                throw std::invalid_argument("Invalid role: " + message["role"]);
+            }
+            if (!message.contains("content") && !message.contains("tool_calls")) {
+                throw std::invalid_argument("Message must contain either 'content' or 'tool_calls'");
+            }
+        }
+
+        return formatted_messages;
+    }
+    
+    /**
+     * @brief 向LLM发送请求并获取回复
+     * @param messages 对话消息列表
+     * @param system_msgs 可选的系统消息
+     * @param max_retries 最大重试次数
+     * @return 生成的assitant content
+     * @throws std::invalid_argument 如果消息无效或回复为空
+     * @throws std::runtime_error 如果API调用失败
+     */
+    std::string ask(
+        const std::vector<Message>& messages,
+        const std::vector<Message>& system_msgs = {},
+        int max_retries = 3
+    ) {
+        std::vector<json> formatted_messages;
+
+        if (!system_msgs.empty()) {
+            auto system_formatted_messages = format_messages(system_msgs);
+            formatted_messages.insert(formatted_messages.end(), system_formatted_messages.begin(), system_formatted_messages.end());
+        }
+        
+        auto _formatted_messages = format_messages(messages);
+        formatted_messages.insert(formatted_messages.end(), _formatted_messages.begin(), _formatted_messages.end());
+
+        json body = {
+            {"model", model},
+            {"messages", formatted_messages},
+            {"temperature", temperature},
+            {"max_tokens", max_tokens}
+        };
+        
+        std::string body_str = body.dump();
+
+        httplib::Headers headers = {
+            {"Authorization", "Bearer " + api_key}
+        };
+
+        int retry = 0;
+
+        while (retry <= max_retries) {
+            // send request
+            auto res = client_->Post(llm_config_.end_point, headers, body_str, "application/json");
+
+            if (!res) {
+                logger->error("Failed to send request: " + httplib::to_string(res.error()));
+            } else if (res->status == 200) {
+                try {
+                    json json_data = json::parse(res->body);
+                    return json_data["choices"][0]["message"]["content"].get<std::string>();
+                } catch (const std::exception & e) {
+                    logger->error("Failed to parse response: " + std::string(e.what()));
+                }
+            } else {
+                logger->error("Failed to send request: status=" + std::to_string(res->status) + ", body=" + res->body);
+            }
+
+            retry++;
+
+            // wait for a while before retrying
+            std::this_thread::sleep_for(std::chrono::milliseconds(500));
+
+            logger->info("Retrying " + std::to_string(retry) + "/" + std::to_string(max_retries));
+        }
+
+        throw std::runtime_error("Failed to get response from LLM");
+    }
+    
+    /**
+     * @brief 使用工具功能向LLM发送请求
+     * @param messages 对话消息列表
+     * @param system_msgs 可选的系统消息
+     * @param timeout 请求超时时间（秒）
+     * @param tools 工具列表
+     * @param tool_choice 工具选择策略
+     * @return 生成的assistant message (content, tool_calls)
+     * @throws std::invalid_argument 如果工具、工具选择或消息无效
+     * @throws std::runtime_error 如果API调用失败
+     */
+    json ask_tool(
+        const std::vector<Message>& messages,
+        const std::vector<Message>& system_msgs = {},
+        const std::vector<json> tools = {},
+        const std::string& tool_choice = "auto",
+        int timeout = 60
+    ) {
+        if (tool_choice != "none" && tool_choice != "auto" && tool_choice != "required") {
+            throw std::invalid_argument("Invalid tool_choice: " + tool_choice);
+        }
+
+        std::vector<json> formatted_messages;
+
+        if (!system_msgs.empty()) {
+            auto system_formatted_messages = format_messages(system_msgs);
+            formatted_messages.insert(formatted_messages.end(), system_formatted_messages.begin(), system_formatted_messages.end());
+        }
+        
+        auto _formatted_messages = format_messages(messages);
+        formatted_messages.insert(formatted_messages.end(), _formatted_messages.begin(), _formatted_messages.end());
+
+        if (!tools.empty()) {
+            for (const json& tool : tools) {
+                if (!tool.contains("type")) {
+                    throw std::invalid_argument("Tool must contain 'type' field");
+                }
+            }
+        }
+        
+        json body = {
+            {"model", model},
+            {"messages", formatted_messages},
+            {"temperature", temperature},
+            {"max_tokens", max_tokens},
+            {"tools", tools},
+            {"tool_choice", tool_choice}
+        };
+
+        client_->set_read_timeout(timeout);
+        
+        std::string body_str = body.dump();
+
+        httplib::Headers headers = {
+            {"Authorization", "Bearer " + api_key}
+        };
+
+        int retry = 0;
+
+        while (retry <= max_retries) {
+            // send request
+            auto res = client_->Post(llm_config_.end_point, headers, body_str, "application/json");
+
+            if (!res) {
+                logger->error("Failed to send request: " + httplib::to_string(res.error()));
+            } else if (res->status == 200) {
+                try {
+                    json json_data = json::parse(res->body);
+                    return json_data["choices"][0]["message"];
+                } catch (const std::exception & e) {
+                    logger->error("Failed to parse response: " + std::string(e.what()));
+                }
+            } else {
+                logger->error("Failed to send request: status=" + std::to_string(res->status) + ", body=" + res->body);
+            }
+
+            retry++;
+
+            // wait for a while before retrying
+            std::this_thread::sleep_for(std::chrono::milliseconds(500));
+
+            logger->info("Retrying " + std::to_string(retry) + "/" + std::to_string(max_retries));
+        }
+
+        throw std::runtime_error("Failed to get response from LLM");
+        
+    }
+};
+
+} // namespace humanus
+
+#endif // HUMANUS_LLM_H

logger.h

@@ -0,0 +1,64 @@
+#ifndef HUMANUSlogger_H
+#define HUMANUSlogger_H
+
+#include "spdlog/spdlog.h"
+#include "spdlog/sinks/stdout_color_sinks.h"
+#include "spdlog/sinks/basic_file_sink.h"
+#include "spdlog/sinks/rotating_file_sink.h"
+#include "spdlog/sinks/daily_file_sink.h"
+#include "spdlog/sinks/dist_sink.h"
+
+#include <string>
+
+namespace humanus {
+
+static spdlog::level::level_enum _print_level = spdlog::level::info;
+
+static std::shared_ptr<spdlog::logger> logger = spdlog::default_logger();
+
+/**
+ * @brief 调整日志级别
+ * @param print_level 控制台输出日志级别
+ * @param logfile_level 文件记录日志级别
+ * @param name 日志文件名前缀
+ * @return 日志记录器实例
+ */
+std::shared_ptr<spdlog::logger> define_log_level(spdlog::level::level_enum print_level = spdlog::level::info, 
+                                               spdlog::level::level_enum logfile_level = spdlog::level::debug, 
+                                               std::string name = "") {
+    _print_level = print_level;
+
+    auto current_date = std::chrono::system_clock::now();
+    auto in_time_t = std::chrono::system_clock::to_time_t(current_date);
+    
+    std::stringstream ss;
+    std::tm tm_info = *std::localtime(&in_time_t);
+    ss << std::put_time(&tm_info, "%Y%m%d");
+    std::string formatted_date = ss.str(); // YYYYMMDD
+    
+    std::string log_name = name.empty() ? formatted_date : name + "_" + formatted_date;
+    std::string log_file_path = (PROJECT_ROOT / "logs" / (log_name + ".log")).string();
+
+    // 确保日志目录存在
+    std::filesystem::create_directories((PROJECT_ROOT / "logs").string());
+
+    // 重置日志输出
+    // 清除现有的sinks
+    logger->sinks().clear();
+    
+    // 添加标准错误输出sink，相当于Python中的sys.stderr
+    auto stderr_sink = std::make_shared<spdlog::sinks::stderr_color_sink_mt>();
+    stderr_sink->set_level(print_level);
+    logger->sinks().push_back(stderr_sink);
+    
+    // 添加文件sink，相当于Python中的PROJECT_ROOT / f"logs/{log_name}.log"
+    auto file_sink = std::make_shared<spdlog::sinks::basic_file_sink_mt>(log_file_path, true);
+    file_sink->set_level(logfile_level);
+    logger->sinks().push_back(file_sink);
+    
+    return logger;
+}
+
+} // namespace humanus
+
+#endif

main.cpp

@@ -0,0 +1,19 @@
+#include "agent/manus.h"
+#include "logger.h"
+
+using namespace humanus;
+
+int main() {
+    Manus agent = Manus();
+    while (true) {
+        std::string prompt;
+        std::cout << "Enter your prompt (or 'exit' to quit): ";
+        std::getline(std::cin, prompt);
+        if (prompt == "exit") {
+            logger->info("Goodbye!");
+            break;
+        }
+        logger->info("Processing your request...");
+        agent.run(prompt);
+    }
+}

mcp

@@ -0,0 +1 @@
+Subproject commit 84e2e092f0b90e44aede47469dc58c1b78e7db36

prompt.h

@@ -0,0 +1,82 @@
+#ifndef HUMANUS_PROMPT_H
+#define HUMANUS_PROMPT_H
+
+namespace humanus {
+
+namespace prompt {
+
+namespace manus {
+const char* SYSTEM_PROMPT = "\
+You are OpenManus, an all-capable AI assistant, aimed at solving any task presented by the user. You have various tools at your disposal that you can call upon to efficiently complete complex requests. Whether it's programming, information retrieval, file processing, or web browsing, you can handle it all.";
+
+const char* NEXT_STEP_PROMPT = R"(You can interact with the computer using PythonExecute, save important content and information files through FileSaver, open browsers with BrowserUseTool, and retrieve information using GoogleSearch.
+
+PythonExecute: Execute Python code to interact with the computer system, data processing, automation tasks, etc.
+
+FileSaver: Save files locally, such as txt, py, html, etc.
+
+BrowserUseTool: Open, browse, and use web browsers.If you open a local HTML file, you must provide the absolute path to the file.
+
+GoogleSearch: Perform web information retrieval
+
+Based on user needs, proactively select the most appropriate tool or combination of tools. For complex tasks, you can break down the problem and use different tools step by step to solve it. After using each tool, clearly explain the execution results and suggest the next steps.)";
+} // namespace manus
+
+namespace planning {
+const char* PLANNING_SYSTEM_PROMPT = R"(Based on the current state, what's your next step?
+Consider:
+1. Do you need to create or refine a plan?
+2. Are you ready to execute a specific step?
+3. Have you completed the task?
+
+Provide reasoning, then select the appropriate tool or action.)";
+
+const char* NEXT_STEP_PROMPT = R"(Based on the current state, what's your next step?
+Consider:
+1. Do you need to create or refine a plan?
+2. Are you ready to execute a specific step?
+3. Have you completed the task?
+
+Provide reasoning, then select the appropriate tool or action.)";
+} // namespace planning
+
+namespace swe {
+const char* SYSTEM_PROMPT = R"(SETTING: You are an autonomous programmer, and you're working directly in the command line with a special interface.
+
+The special interface consists of a file editor that shows you {WINDOW} lines of a file at a time.
+In addition to typical bash commands, you can also use specific commands to help you navigate and edit files.
+To call a command, you need to invoke it with a function call/tool call.
+
+Please note that THE EDIT COMMAND REQUIRES PROPER INDENTATION.
+If you'd like to add the line '        print(x)' you must fully write that out, with all those spaces before the code! Indentation is important and code that is not indented correctly will fail and require fixing before it can be run.
+
+RESPONSE FORMAT:
+Your shell prompt is formatted as follows:
+(Open file: <path>)
+(Current directory: <cwd>)
+bash-$
+
+First, you should _always_ include a general thought about what you're going to do next.
+Then, for every response, you must include exactly _ONE_ tool call/function call.
+
+Remember, you should always include a _SINGLE_ tool call/function call and then wait for a response from the shell before continuing with more discussion and commands. Everything you include in the DISCUSSION section will be saved for future reference.
+If you'd like to issue two commands at once, PLEASE DO NOT DO THAT! Please instead first submit just the first tool call, and then after receiving a response you'll be able to issue the second tool call.
+Note that the environment does NOT support interactive session commands (e.g. python, vim), so please do not invoke them.)";
+
+const char* NEXT_STEP_TEMPLATE = R"({observation}
+(Open file: {open_file})
+(Current directory: {working_dir})
+bash-$)";
+} // namespace swe
+
+namespace toolcall {
+const char* SYSTEM_PROMPT = "You are an agent that can execute tool calls";
+
+const char* NEXT_STEP_PROMPT = "If you want to stop interaction, use `terminate` tool/function call.";
+} // namespace toolcall
+
+} // namespace prompt
+
+} // namespace humanus
+
+#endif // HUMANUS_PROMPT_H

schema.h

@@ -0,0 +1,231 @@
+#ifndef HUMANUS_SCHEMA_H
+#define HUMANUS_SCHEMA_H
+
+#include "mcp_message.h"
+
+namespace humanus {
+
+using json = mcp::json;
+
+// Agent execution states
+enum class AgentState {
+    IDLE = 0,
+    RUNNING = 1,
+    FINISHED = 2,
+    ERROR = 3
+};
+
+std::map<AgentState, std::string> agent_state_map = {
+    {AgentState::IDLE, "IDLE"},
+    {AgentState::RUNNING, "RUNNING"},
+    {AgentState::FINISHED, "FINISHED"},
+    {AgentState::ERROR, "ERROR"}
+};
+
+struct Function {
+    std::string name;
+    json arguments;
+
+    json to_json() const {
+        json function;
+        function["name"] = name;
+        function["arguments"] = arguments;
+        return function;
+    }
+    
+    bool empty() const {
+        return name.empty() && arguments.empty();
+    }
+};
+
+// Represents a tool/function call in a message
+struct ToolCall {
+    std::string id;
+    std::string type;
+    Function function;
+
+    bool empty() const {
+        return id.empty() && type.empty() && function.empty();
+    }
+
+    json to_json() const {
+        json tool_call;
+        tool_call["id"] = id;
+        tool_call["type"] = type;
+        tool_call["function"] = function.to_json().dump();
+        return tool_call;
+    }
+
+    static ToolCall from_json(const json& tool_call_json) {
+        ToolCall tool_call;
+        tool_call.id = tool_call_json["id"];
+        tool_call.type = tool_call_json["type"];
+        tool_call.function.name = tool_call_json["function"]["name"];
+        tool_call.function.arguments = tool_call_json["function"]["arguments"];
+        return tool_call;
+    }
+
+    static std::vector<ToolCall> from_json_list(const json& tool_calls_json) {
+        std::vector<ToolCall> tool_calls;
+        for (const auto& tool_call_json : tool_calls_json) {
+            tool_calls.push_back(from_json(tool_call_json));
+        }
+        return tool_calls;
+    }
+};
+
+// Represents a chat message in the conversation
+struct Message {
+    std::string role;
+    json content;
+    std::string name;
+    std::string tool_call_id;
+    std::vector<ToolCall> tool_calls;
+
+    Message(const std::string& role, const json& content, const std::string& name = "", const std::string& tool_call_id = "", const std::vector<ToolCall> tool_calls = {})
+    : role(role), content(content), name(name), tool_call_id(tool_call_id), tool_calls(tool_calls) {}
+
+    std::vector<Message> operator+(const Message& other) const {
+        return {*this, other};
+    }
+
+    std::vector<Message> operator+(const std::vector<Message>& other) const {
+        std::vector<Message> result;
+        result.reserve(1 + other.size());
+        result.push_back(*this);
+        result.insert(result.end(), other.begin(), other.end());
+        return result;
+    }
+
+    friend std::vector<Message> operator+(const std::vector<Message>& lhs, const Message& rhs) {
+        std::vector<Message> result;
+        result.reserve(lhs.size() + 1);
+        result.insert(result.end(), lhs.begin(), lhs.end());
+        result.push_back(rhs);
+        return result;
+    }
+
+    friend std::vector<Message> operator+(const std::vector<Message>& lhs, const std::vector<Message>& rhs) {
+        std::vector<Message> result;
+        result.reserve(lhs.size() + rhs.size());
+        result.insert(result.end(), lhs.begin(), lhs.end());
+        result.insert(result.end(), rhs.begin(), rhs.end());
+        return result;
+    }
+
+    // Convert message to dictionary format
+    json to_json() const {
+        json message;
+        message["role"] = role;
+        if (!content.is_null()) {
+            message["content"] = content;
+        }
+        if (!tool_calls.empty()) {
+            message["tool_calls"] = json::array();
+            for (const auto& call : tool_calls) {
+                message["tool_calls"].push_back(call.to_json());
+            }
+        }
+        if (!name.empty()) {
+            message["name"] = name;
+        }
+        if (!tool_call_id.empty()) {
+            message["tool_call_id"] = tool_call_id;
+        }
+        return message;
+    }
+
+    // Convert message to dictionary format
+    json to_dict() const {
+        return to_json();
+    }
+
+    static Message user_message(const json& content) {
+        return Message("user", content);
+    }
+
+    static Message system_message(const json& content) {
+        return Message("system", content);
+    }
+
+    static Message assistant_message(const json& content) {
+        return Message("assistant", content);
+    }
+
+    static Message tool_message(const json& content, const std::string& name =  "", const std::string& tool_call_id = "") {
+        return Message("tool", content, name, tool_call_id);
+    }
+
+    /**
+     * @brief Create ToolCallsMessage from raw tool calls.
+     * @param tool_calls Raw tool calls from LLM
+     * @param content Optional message content
+     * @param kwargs Other optional arguments
+     * @return Message with tool calls
+     */
+    static Message from_tool_calls(const std::vector<ToolCall>& tool_calls, const json& content = json::object()) {
+        std::vector<json> formatted_calls;
+        formatted_calls.reserve(tool_calls.size());
+        
+        for (const auto& call : tool_calls) {
+            json formatted_call;
+            formatted_call["id"] = call.id;
+            formatted_call["type"] = "function";
+            formatted_call["function"] = call.function.to_json();
+            formatted_calls.push_back(formatted_call);
+        }
+        
+        return Message("assistant", content, "", "", tool_calls);
+    }
+};
+
+struct Memory {
+    std::vector<Message> messages;
+    int max_messages;
+
+    Memory(int max_messages = 100) : max_messages(max_messages) {}
+
+    // Add a message to the memory
+    void add_message(const Message& message) {
+        messages.push_back(message);
+        if (messages.size() > max_messages) {
+            messages.erase(messages.begin());
+        }
+    }
+
+    // Add multiple messages to the memory
+    void add_messages(const std::vector<Message>& messages) {
+        for (const auto& message : messages) {
+            add_message(message);
+        }
+    }
+
+    // Set the messages
+    void set_messages(const std::vector<Message>& messages) {
+        this->messages = messages;
+    }
+    
+    // Clear all messages
+    void clear() {
+        messages.clear();
+    }
+
+    // Get the last n messages
+    std::vector<Message> get_recent_messages(int n) const {
+        return std::vector<Message>(messages.end() - n, messages.end());
+    }
+
+    // Convert messages to list of dicts
+    json to_json_list() const {
+        json memory = json::array();
+        for (const auto& message : messages) {
+            memory.push_back(message.to_json());
+        }
+        return memory;
+    }
+};
+
+
+} // namespace humanus
+
+#endif // HUMANUS_SCHEMA_H

server/CMakeLists.txt

@@ -0,0 +1,37 @@
+# 服务器组件CMakeLists.txt
+cmake_minimum_required(VERSION 3.10)
+
+# 添加源文件
+set(SERVER_SOURCES
+    python_execute.cpp
+)
+
+# 添加库
+add_library(server STATIC ${SERVER_SOURCES})
+
+# 链接依赖库
+target_link_libraries(server PRIVATE mcp)
+
+find_package(Python3 REQUIRED)
+
+if(Python3_FOUND)
+    target_link_libraries(server PRIVATE ${Python3_LIBRARIES})
+endif()
+
+# 包含目录
+target_include_directories(server PRIVATE 
+    ${CMAKE_CURRENT_SOURCE_DIR}
+    ${CMAKE_CURRENT_SOURCE_DIR}/../
+    ${CMAKE_CURRENT_SOURCE_DIR}/../mcp/include
+)
+
+# 添加MCP服务器可执行文件
+add_executable(mcp_server mcp_server_main.cpp)
+target_link_libraries(mcp_server PRIVATE server mcp Threads::Threads ${OPENSSL_LIBRARIES})
+if(Python3_FOUND)
+    target_link_libraries(mcp_server PRIVATE ${Python3_LIBRARIES})
+endif()
+
+# 安装
+install(TARGETS server DESTINATION lib)
+install(TARGETS mcp_server DESTINATION bin) 

server/mcp_server_main.cpp

@@ -0,0 +1,41 @@
+/**
+ * @file mcp_server_main.cpp
+ * @brief OpenManus MCP服务器实现
+ * 
+ * 这个文件实现了OpenManus的MCP服务器，提供工具调用功能。
+ * 当前实现了PythonExecute工具。
+ */
+
+#include "mcp/include/mcp_server.h"
+#include "mcp/include/mcp_tool.h"
+#include "mcp/include/mcp_resource.h"
+
+#include <iostream>
+#include <string>
+#include <memory>
+#include <filesystem>
+
+// 导入Python执行工具
+extern void register_python_execute_tool(mcp::server& server);
+
+int main() {
+    // 创建并配置服务器
+    mcp::server server("localhost", 8818);
+    server.set_server_info("OpenManusMCPServer", "0.0.1");
+    
+    // 设置服务器能力
+    mcp::json capabilities = {
+        {"tools", mcp::json::object()}
+    };
+    server.set_capabilities(capabilities);
+    
+    // 注册Python执行工具
+    register_python_execute_tool(server);
+    
+    // 启动服务器
+    std::cout << "启动OpenManus MCP服务器，地址: localhost:8818..." << std::endl;
+    std::cout << "按Ctrl+C停止服务器" << std::endl;
+    server.start(true);  // 阻塞模式
+    
+    return 0;
+} 

server/python_execute.cpp

@@ -0,0 +1,179 @@
+/**
+ * @file python_execute.cpp
+ * @brief OpenManus Python执行工具实现
+ * 
+ * 这个文件实现了OpenManus的Python执行工具，使用Python.h直接调用Python解释器。
+ */
+
+#include "mcp/include/mcp_server.h"
+#include "mcp/include/mcp_tool.h"
+#include "mcp/include/mcp_resource.h"
+
+#include <iostream>
+#include <string>
+#include <memory>
+#include <stdexcept>
+
+// 检查是否找到Python
+#ifdef PYTHON_FOUND
+#include <Python.h>
+#endif
+
+/**
+ * @class python_interpreter
+ * @brief Python解释器类，用于执行Python代码
+ */
+class python_interpreter {
+public:
+    /**
+     * @brief 构造函数，初始化Python解释器
+     */
+    python_interpreter() {
+#ifdef PYTHON_FOUND
+        Py_Initialize();
+#endif
+    }
+
+    /**
+     * @brief 析构函数，释放Python解释器
+     */
+    ~python_interpreter() {
+#ifdef PYTHON_FOUND
+        Py_Finalize();
+#endif
+    }
+
+    /**
+     * @brief 执行Python代码
+     * @param input 包含Python代码的JSON对象
+     * @return 执行结果的JSON对象
+     */
+    mcp::json forward(const mcp::json& input) const {
+#ifdef PYTHON_FOUND
+        if (input.contains("code") && input["code"].is_string()) {
+            std::string code = input["code"].get<std::string>();
+
+            // Create scope to manage Python objects automatically
+            PyObject *main_module = PyImport_AddModule("__main__");
+            PyObject *main_dict = PyModule_GetDict(main_module);
+            PyObject *sys_module = PyImport_ImportModule("sys");
+            PyObject *io_module = PyImport_ImportModule("io");
+            PyObject *string_io = PyObject_GetAttrString(io_module, "StringIO");
+            PyObject *sys_stdout = PyObject_CallObject(string_io, nullptr);
+            PyObject *sys_stderr = PyObject_CallObject(string_io, nullptr);
+
+            // Replace sys.stdout and sys.stderr with our StringIO objects
+            PySys_SetObject("stdout", sys_stdout);
+            PySys_SetObject("stderr", sys_stderr);
+
+            // Execute the Python code
+            PyObject *result = PyRun_String(code.c_str(), Py_file_input, main_dict, main_dict);
+            if (!result) {
+                PyErr_Print();
+            }
+            Py_XDECREF(result);
+
+            // Fetch the output and error from the StringIO object
+            PyObject *out_value = PyObject_CallMethod(sys_stdout, "getvalue", nullptr);
+            PyObject *err_value = PyObject_CallMethod(sys_stderr, "getvalue", nullptr);
+
+            // Convert Python string to C++ string
+            std::string output = PyUnicode_AsUTF8(out_value);
+            std::string error = PyUnicode_AsUTF8(err_value);
+
+            // Restore the original sys.stdout and sys.stderr
+            PySys_SetObject("stdout", PySys_GetObject("stdout"));
+            PySys_SetObject("stderr", PySys_GetObject("stderr"));
+
+            // Clean up
+            Py_DECREF(sys_stdout);
+            Py_DECREF(sys_stderr);
+            Py_DECREF(string_io);
+            Py_DECREF(io_module);
+            Py_DECREF(sys_module);
+
+            // Prepare JSON output
+            mcp::json result_json;
+            if (!output.empty()) {
+                result_json["output"] = output;
+            }
+            if (!error.empty()) {
+                result_json["error"] = error;
+            }
+
+            if (result_json.empty()) {
+                std::string last_line;
+                std::istringstream code_stream(code);
+                while (std::getline(code_stream, last_line, '\n')) {}
+                size_t pos = last_line.find_last_of(';') + 1;
+                pos = last_line.find("=") + 1;
+                while (pos < last_line.size() && isblank(last_line[pos])) {
+                    pos++;
+                }
+                if (pos != std::string::npos) {
+                    last_line = last_line.substr(pos);
+                }
+
+                return mcp::json{{"warning", "No output. Maybe try with print(" + last_line + ")?"}};
+            }
+
+            return result_json;
+        } else {
+            return mcp::json{{"error", "Invalid parameters or code not provided"}};
+        }
+#else
+        return mcp::json{{"error", "Python interpreter not available"}};
+#endif
+    }
+};
+
+// 全局Python解释器实例
+static python_interpreter interpreter;
+
+// Python执行工具处理函数
+mcp::json python_execute_handler(const mcp::json& args) {
+    if (!args.contains("code")) {
+        std::cout << args.dump() << std::endl;
+        throw mcp::mcp_exception(mcp::error_code::invalid_params, "缺少'code'参数");
+    }
+    
+    try {
+        // 使用Python解释器执行代码
+        mcp::json result = interpreter.forward(args);
+        
+        // 格式化输出结果
+        std::string output;
+        if (result.contains("output")) {
+            output += result["output"].get<std::string>();
+        }
+        if (result.contains("error")) {
+            output += result["error"].get<std::string>();
+        }
+        if (result.contains("warning")) {
+            output += result["warning"].get<std::string>();
+        }
+        
+        if (output.empty()) {
+            output = "Executed successfully but w/o output. Maybe you should print more information.";
+        }
+        
+        return {{
+            {"type", "text"},
+            {"text", output}
+        }};
+    } catch (const std::exception& e) {
+        throw mcp::mcp_exception(mcp::error_code::internal_error, 
+                                "执行Python代码失败: " + std::string(e.what()));
+    }
+}
+
+// 注册Python执行工具的函数
+void register_python_execute_tool(mcp::server& server) {
+    // 注册PythonExecute工具
+    mcp::tool python_tool = mcp::tool_builder("PythonExecute")
+        .with_description("执行Python代码并返回结果")
+        .with_string_param("code", "要执行的Python代码", true)
+        .build();
+    
+    server.register_tool(python_tool, python_execute_handler);
+}

spdlog/async.h

@@ -0,0 +1,100 @@
+// Copyright(c) 2015-present, Gabi Melman & spdlog contributors.
+// Distributed under the MIT License (http://opensource.org/licenses/MIT)
+
+#pragma once
+
+//
+// Async logging using global thread pool
+// All loggers created here share same global thread pool.
+// Each log message is pushed to a queue along with a shared pointer to the
+// logger.
+// If a logger deleted while having pending messages in the queue, it's actual
+// destruction will defer
+// until all its messages are processed by the thread pool.
+// This is because each message in the queue holds a shared_ptr to the
+// originating logger.
+
+#include <spdlog/async_logger.h>
+#include <spdlog/details/registry.h>
+#include <spdlog/details/thread_pool.h>
+
+#include <functional>
+#include <memory>
+#include <mutex>
+
+namespace spdlog {
+
+namespace details {
+static const size_t default_async_q_size = 8192;
+}
+
+// async logger factory - creates async loggers backed with thread pool.
+// if a global thread pool doesn't already exist, create it with default queue
+// size of 8192 items and single thread.
+template <async_overflow_policy OverflowPolicy = async_overflow_policy::block>
+struct async_factory_impl {
+    template <typename Sink, typename... SinkArgs>
+    static std::shared_ptr<async_logger> create(std::string logger_name, SinkArgs &&...args) {
+        auto &registry_inst = details::registry::instance();
+
+        // create global thread pool if not already exists..
+
+        auto &mutex = registry_inst.tp_mutex();
+        std::lock_guard<std::recursive_mutex> tp_lock(mutex);
+        auto tp = registry_inst.get_tp();
+        if (tp == nullptr) {
+            tp = std::make_shared<details::thread_pool>(details::default_async_q_size, 1U);
+            registry_inst.set_tp(tp);
+        }
+
+        auto sink = std::make_shared<Sink>(std::forward<SinkArgs>(args)...);
+        auto new_logger = std::make_shared<async_logger>(std::move(logger_name), std::move(sink),
+                                                         std::move(tp), OverflowPolicy);
+        registry_inst.initialize_logger(new_logger);
+        return new_logger;
+    }
+};
+
+using async_factory = async_factory_impl<async_overflow_policy::block>;
+using async_factory_nonblock = async_factory_impl<async_overflow_policy::overrun_oldest>;
+
+template <typename Sink, typename... SinkArgs>
+inline std::shared_ptr<spdlog::logger> create_async(std::string logger_name,
+                                                    SinkArgs &&...sink_args) {
+    return async_factory::create<Sink>(std::move(logger_name),
+                                       std::forward<SinkArgs>(sink_args)...);
+}
+
+template <typename Sink, typename... SinkArgs>
+inline std::shared_ptr<spdlog::logger> create_async_nb(std::string logger_name,
+                                                       SinkArgs &&...sink_args) {
+    return async_factory_nonblock::create<Sink>(std::move(logger_name),
+                                                std::forward<SinkArgs>(sink_args)...);
+}
+
+// set global thread pool.
+inline void init_thread_pool(size_t q_size,
+                             size_t thread_count,
+                             std::function<void()> on_thread_start,
+                             std::function<void()> on_thread_stop) {
+    auto tp = std::make_shared<details::thread_pool>(q_size, thread_count, on_thread_start,
+                                                     on_thread_stop);
+    details::registry::instance().set_tp(std::move(tp));
+}
+
+inline void init_thread_pool(size_t q_size,
+                             size_t thread_count,
+                             std::function<void()> on_thread_start) {
+    init_thread_pool(q_size, thread_count, on_thread_start, [] {});
+}
+
+inline void init_thread_pool(size_t q_size, size_t thread_count) {
+    init_thread_pool(
+        q_size, thread_count, [] {}, [] {});
+}
+
+// get the global thread pool.
+inline std::shared_ptr<spdlog::details::thread_pool> thread_pool() {
+    return details::registry::instance().get_tp();
+}
+}  // namespace spdlog

spdlog/async_logger-inl.h

@@ -0,0 +1,84 @@
+// Copyright(c) 2015-present, Gabi Melman & spdlog contributors.
+// Distributed under the MIT License (http://opensource.org/licenses/MIT)
+
+#pragma once
+
+#ifndef SPDLOG_HEADER_ONLY
+    #include <spdlog/async_logger.h>
+#endif
+
+#include <spdlog/details/thread_pool.h>
+#include <spdlog/sinks/sink.h>
+
+#include <memory>
+#include <string>
+
+SPDLOG_INLINE spdlog::async_logger::async_logger(std::string logger_name,
+                                                 sinks_init_list sinks_list,
+                                                 std::weak_ptr<details::thread_pool> tp,
+                                                 async_overflow_policy overflow_policy)
+    : async_logger(std::move(logger_name),
+                   sinks_list.begin(),
+                   sinks_list.end(),
+                   std::move(tp),
+                   overflow_policy) {}
+
+SPDLOG_INLINE spdlog::async_logger::async_logger(std::string logger_name,
+                                                 sink_ptr single_sink,
+                                                 std::weak_ptr<details::thread_pool> tp,
+                                                 async_overflow_policy overflow_policy)
+    : async_logger(
+          std::move(logger_name), {std::move(single_sink)}, std::move(tp), overflow_policy) {}
+
+// send the log message to the thread pool
+SPDLOG_INLINE void spdlog::async_logger::sink_it_(const details::log_msg &msg){
+    SPDLOG_TRY{if (auto pool_ptr = thread_pool_.lock()){
+        pool_ptr->post_log(shared_from_this(), msg, overflow_policy_);
+}
+else {
+    throw_spdlog_ex("async log: thread pool doesn't exist anymore");
+}
+}
+SPDLOG_LOGGER_CATCH(msg.source)
+}
+
+// send flush request to the thread pool
+SPDLOG_INLINE void spdlog::async_logger::flush_(){
+    SPDLOG_TRY{if (auto pool_ptr = thread_pool_.lock()){
+        pool_ptr->post_flush(shared_from_this(), overflow_policy_);
+}
+else {
+    throw_spdlog_ex("async flush: thread pool doesn't exist anymore");
+}
+}
+SPDLOG_LOGGER_CATCH(source_loc())
+}
+
+//
+// backend functions - called from the thread pool to do the actual job
+//
+SPDLOG_INLINE void spdlog::async_logger::backend_sink_it_(const details::log_msg &msg) {
+    for (auto &sink : sinks_) {
+        if (sink->should_log(msg.level)) {
+            SPDLOG_TRY { sink->log(msg); }
+            SPDLOG_LOGGER_CATCH(msg.source)
+        }
+    }
+
+    if (should_flush_(msg)) {
+        backend_flush_();
+    }
+}
+
+SPDLOG_INLINE void spdlog::async_logger::backend_flush_() {
+    for (auto &sink : sinks_) {
+        SPDLOG_TRY { sink->flush(); }
+        SPDLOG_LOGGER_CATCH(source_loc())
+    }
+}
+
+SPDLOG_INLINE std::shared_ptr<spdlog::logger> spdlog::async_logger::clone(std::string new_name) {
+    auto cloned = std::make_shared<spdlog::async_logger>(*this);
+    cloned->name_ = std::move(new_name);
+    return cloned;
+}

spdlog/async_logger.h

@@ -0,0 +1,74 @@
+// Copyright(c) 2015-present, Gabi Melman & spdlog contributors.
+// Distributed under the MIT License (http://opensource.org/licenses/MIT)
+
+#pragma once
+
+// Fast asynchronous logger.
+// Uses pre allocated queue.
+// Creates a single back thread to pop messages from the queue and log them.
+//
+// Upon each log write the logger:
+//    1. Checks if its log level is enough to log the message
+//    2. Push a new copy of the message to a queue (or block the caller until
+//    space is available in the queue)
+// Upon destruction, logs all remaining messages in the queue before
+// destructing..
+
+#include <spdlog/logger.h>
+
+namespace spdlog {
+
+// Async overflow policy - block by default.
+enum class async_overflow_policy {
+    block,           // Block until message can be enqueued
+    overrun_oldest,  // Discard oldest message in the queue if full when trying to
+                     // add new item.
+    discard_new      // Discard new message if the queue is full when trying to add new item.
+};
+
+namespace details {
+class thread_pool;
+}
+
+class SPDLOG_API async_logger final : public std::enable_shared_from_this<async_logger>,
+                                      public logger {
+    friend class details::thread_pool;
+
+public:
+    template <typename It>
+    async_logger(std::string logger_name,
+                 It begin,
+                 It end,
+                 std::weak_ptr<details::thread_pool> tp,
+                 async_overflow_policy overflow_policy = async_overflow_policy::block)
+        : logger(std::move(logger_name), begin, end),
+          thread_pool_(std::move(tp)),
+          overflow_policy_(overflow_policy) {}
+
+    async_logger(std::string logger_name,
+                 sinks_init_list sinks_list,
+                 std::weak_ptr<details::thread_pool> tp,
+                 async_overflow_policy overflow_policy = async_overflow_policy::block);
+
+    async_logger(std::string logger_name,
+                 sink_ptr single_sink,
+                 std::weak_ptr<details::thread_pool> tp,
+                 async_overflow_policy overflow_policy = async_overflow_policy::block);
+
+    std::shared_ptr<logger> clone(std::string new_name) override;
+
+protected:
+    void sink_it_(const details::log_msg &msg) override;
+    void flush_() override;
+    void backend_sink_it_(const details::log_msg &incoming_log_msg);
+    void backend_flush_();
+
+private:
+    std::weak_ptr<details::thread_pool> thread_pool_;
+    async_overflow_policy overflow_policy_;
+};
+}  // namespace spdlog
+
+#ifdef SPDLOG_HEADER_ONLY
+    #include "async_logger-inl.h"
+#endif

spdlog/cfg/argv.h

@@ -0,0 +1,40 @@
+// Copyright(c) 2015-present, Gabi Melman & spdlog contributors.
+// Distributed under the MIT License (http://opensource.org/licenses/MIT)
+
+#pragma once
+#include <spdlog/cfg/helpers.h>
+#include <spdlog/details/registry.h>
+
+//
+// Init log levels using each argv entry that starts with "SPDLOG_LEVEL="
+//
+// set all loggers to debug level:
+// example.exe "SPDLOG_LEVEL=debug"
+
+// set logger1 to trace level
+// example.exe "SPDLOG_LEVEL=logger1=trace"
+
+// turn off all logging except for logger1 and logger2:
+// example.exe "SPDLOG_LEVEL=off,logger1=debug,logger2=info"
+
+namespace spdlog {
+namespace cfg {
+
+// search for SPDLOG_LEVEL= in the args and use it to init the levels
+inline void load_argv_levels(int argc, const char **argv) {
+    const std::string spdlog_level_prefix = "SPDLOG_LEVEL=";
+    for (int i = 1; i < argc; i++) {
+        std::string arg = argv[i];
+        if (arg.find(spdlog_level_prefix) == 0) {
+            auto levels_string = arg.substr(spdlog_level_prefix.size());
+            helpers::load_levels(levels_string);
+        }
+    }
+}
+
+inline void load_argv_levels(int argc, char **argv) {
+    load_argv_levels(argc, const_cast<const char **>(argv));
+}
+
+}  // namespace cfg
+}  // namespace spdlog

spdlog/cfg/env.h

@@ -0,0 +1,36 @@
+// Copyright(c) 2015-present, Gabi Melman & spdlog contributors.
+// Distributed under the MIT License (http://opensource.org/licenses/MIT)
+
+#pragma once
+#include <spdlog/cfg/helpers.h>
+#include <spdlog/details/os.h>
+#include <spdlog/details/registry.h>
+
+//
+// Init levels and patterns from env variables SPDLOG_LEVEL
+// Inspired from Rust's "env_logger" crate (https://crates.io/crates/env_logger).
+// Note - fallback to "info" level on unrecognized levels
+//
+// Examples:
+//
+// set global level to debug:
+// export SPDLOG_LEVEL=debug
+//
+// turn off all logging except for logger1:
+// export SPDLOG_LEVEL="*=off,logger1=debug"
+//
+
+// turn off all logging except for logger1 and logger2:
+// export SPDLOG_LEVEL="off,logger1=debug,logger2=info"
+
+namespace spdlog {
+namespace cfg {
+inline void load_env_levels(const char* var = "SPDLOG_LEVEL") {
+    auto env_val = details::os::getenv(var);
+    if (!env_val.empty()) {
+        helpers::load_levels(env_val);
+    }
+}
+
+}  // namespace cfg
+}  // namespace spdlog

spdlog/cfg/helpers-inl.h

@@ -0,0 +1,107 @@
+// Copyright(c) 2015-present, Gabi Melman & spdlog contributors.
+// Distributed under the MIT License (http://opensource.org/licenses/MIT)
+
+#pragma once
+
+#ifndef SPDLOG_HEADER_ONLY
+    #include <spdlog/cfg/helpers.h>
+#endif
+
+#include <spdlog/details/os.h>
+#include <spdlog/details/registry.h>
+#include <spdlog/spdlog.h>
+
+#include <algorithm>
+#include <sstream>
+#include <string>
+#include <utility>
+
+namespace spdlog {
+namespace cfg {
+namespace helpers {
+
+// inplace convert to lowercase
+inline std::string &to_lower_(std::string &str) {
+    std::transform(str.begin(), str.end(), str.begin(), [](char ch) {
+        return static_cast<char>((ch >= 'A' && ch <= 'Z') ? ch + ('a' - 'A') : ch);
+    });
+    return str;
+}
+
+// inplace trim spaces
+inline std::string &trim_(std::string &str) {
+    const char *spaces = " \n\r\t";
+    str.erase(str.find_last_not_of(spaces) + 1);
+    str.erase(0, str.find_first_not_of(spaces));
+    return str;
+}
+
+// return (name,value) trimmed pair from given "name=value" string.
+// return empty string on missing parts
+// "key=val" => ("key", "val")
+// " key  =  val " => ("key", "val")
+// "key=" => ("key", "")
+// "val" => ("", "val")
+
+inline std::pair<std::string, std::string> extract_kv_(char sep, const std::string &str) {
+    auto n = str.find(sep);
+    std::string k, v;
+    if (n == std::string::npos) {
+        v = str;
+    } else {
+        k = str.substr(0, n);
+        v = str.substr(n + 1);
+    }
+    return std::make_pair(trim_(k), trim_(v));
+}
+
+// return vector of key/value pairs from sequence of "K1=V1,K2=V2,.."
+// "a=AAA,b=BBB,c=CCC,.." => {("a","AAA"),("b","BBB"),("c", "CCC"),...}
+inline std::unordered_map<std::string, std::string> extract_key_vals_(const std::string &str) {
+    std::string token;
+    std::istringstream token_stream(str);
+    std::unordered_map<std::string, std::string> rv{};
+    while (std::getline(token_stream, token, ',')) {
+        if (token.empty()) {
+            continue;
+        }
+        auto kv = extract_kv_('=', token);
+        rv[kv.first] = kv.second;
+    }
+    return rv;
+}
+
+SPDLOG_INLINE void load_levels(const std::string &input) {
+    if (input.empty() || input.size() > 512) {
+        return;
+    }
+
+    auto key_vals = extract_key_vals_(input);
+    std::unordered_map<std::string, level::level_enum> levels;
+    level::level_enum global_level = level::info;
+    bool global_level_found = false;
+
+    for (auto &name_level : key_vals) {
+        auto &logger_name = name_level.first;
+        auto level_name = to_lower_(name_level.second);
+        auto level = level::from_str(level_name);
+        // ignore unrecognized level names
+        if (level == level::off && level_name != "off") {
+            continue;
+        }
+        if (logger_name.empty())  // no logger name indicate global level
+        {
+            global_level_found = true;
+            global_level = level;
+        } else {
+            levels[logger_name] = level;
+        }
+    }
+
+    details::registry::instance().set_levels(std::move(levels),
+                                             global_level_found ? &global_level : nullptr);
+}
+
+}  // namespace helpers
+}  // namespace cfg
+}  // namespace spdlog

spdlog/cfg/helpers.h

@@ -0,0 +1,29 @@
+// Copyright(c) 2015-present, Gabi Melman & spdlog contributors.
+// Distributed under the MIT License (http://opensource.org/licenses/MIT)
+
+#pragma once
+
+#include <spdlog/common.h>
+#include <unordered_map>
+
+namespace spdlog {
+namespace cfg {
+namespace helpers {
+//
+// Init levels from given string
+//
+// Examples:
+//
+// set global level to debug: "debug"
+// turn off all logging except for logger1: "off,logger1=debug"
+// turn off all logging except for logger1 and logger2: "off,logger1=debug,logger2=info"
+//
+SPDLOG_API void load_levels(const std::string &txt);
+}  // namespace helpers
+
+}  // namespace cfg
+}  // namespace spdlog
+
+#ifdef SPDLOG_HEADER_ONLY
+    #include "helpers-inl.h"
+#endif  // SPDLOG_HEADER_ONLY

spdlog/common-inl.h

@@ -0,0 +1,68 @@
+// Copyright(c) 2015-present, Gabi Melman & spdlog contributors.
+// Distributed under the MIT License (http://opensource.org/licenses/MIT)
+
+#pragma once
+
+#ifndef SPDLOG_HEADER_ONLY
+    #include <spdlog/common.h>
+#endif
+
+#include <algorithm>
+#include <iterator>
+
+namespace spdlog {
+namespace level {
+
+#if __cplusplus >= 201703L
+constexpr
+#endif
+    static string_view_t level_string_views[] SPDLOG_LEVEL_NAMES;
+
+static const char *short_level_names[] SPDLOG_SHORT_LEVEL_NAMES;
+
+SPDLOG_INLINE const string_view_t &to_string_view(spdlog::level::level_enum l) SPDLOG_NOEXCEPT {
+    return level_string_views[l];
+}
+
+SPDLOG_INLINE const char *to_short_c_str(spdlog::level::level_enum l) SPDLOG_NOEXCEPT {
+    return short_level_names[l];
+}
+
+SPDLOG_INLINE spdlog::level::level_enum from_str(const std::string &name) SPDLOG_NOEXCEPT {
+    auto it = std::find(std::begin(level_string_views), std::end(level_string_views), name);
+    if (it != std::end(level_string_views))
+        return static_cast<level::level_enum>(std::distance(std::begin(level_string_views), it));
+
+    // check also for "warn" and "err" before giving up..
+    if (name == "warn") {
+        return level::warn;
+    }
+    if (name == "err") {
+        return level::err;
+    }
+    return level::off;
+}
+}  // namespace level
+
+SPDLOG_INLINE spdlog_ex::spdlog_ex(std::string msg)
+    : msg_(std::move(msg)) {}
+
+SPDLOG_INLINE spdlog_ex::spdlog_ex(const std::string &msg, int last_errno) {
+#ifdef SPDLOG_USE_STD_FORMAT
+    msg_ = std::system_error(std::error_code(last_errno, std::generic_category()), msg).what();
+#else
+    memory_buf_t outbuf;
+    fmt::format_system_error(outbuf, last_errno, msg.c_str());
+    msg_ = fmt::to_string(outbuf);
+#endif
+}
+
+SPDLOG_INLINE const char *spdlog_ex::what() const SPDLOG_NOEXCEPT { return msg_.c_str(); }
+
+SPDLOG_INLINE void throw_spdlog_ex(const std::string &msg, int last_errno) {
+    SPDLOG_THROW(spdlog_ex(msg, last_errno));
+}
+
+SPDLOG_INLINE void throw_spdlog_ex(std::string msg) { SPDLOG_THROW(spdlog_ex(std::move(msg))); }
+
+}  // namespace spdlog

spdlog/common.h

@@ -0,0 +1,406 @@
+// Copyright(c) 2015-present, Gabi Melman & spdlog contributors.
+// Distributed under the MIT License (http://opensource.org/licenses/MIT)
+
+#pragma once
+
+#include <spdlog/details/null_mutex.h>
+#include <spdlog/tweakme.h>
+
+#include <atomic>
+#include <chrono>
+#include <cstdio>
+#include <exception>
+#include <functional>
+#include <initializer_list>
+#include <memory>
+#include <string>
+#include <type_traits>
+
+#ifdef SPDLOG_USE_STD_FORMAT
+    #include <version>
+    #if __cpp_lib_format >= 202207L
+        #include <format>
+    #else
+        #include <string_view>
+    #endif
+#endif
+
+#ifdef SPDLOG_COMPILED_LIB
+    #undef SPDLOG_HEADER_ONLY
+    #if defined(SPDLOG_SHARED_LIB)
+        #if defined(_WIN32)
+            #ifdef spdlog_EXPORTS
+                #define SPDLOG_API __declspec(dllexport)
+            #else  // !spdlog_EXPORTS
+                #define SPDLOG_API __declspec(dllimport)
+            #endif
+        #else  // !defined(_WIN32)
+            #define SPDLOG_API __attribute__((visibility("default")))
+        #endif
+    #else  // !defined(SPDLOG_SHARED_LIB)
+        #define SPDLOG_API
+    #endif
+    #define SPDLOG_INLINE
+#else  // !defined(SPDLOG_COMPILED_LIB)
+    #define SPDLOG_API
+    #define SPDLOG_HEADER_ONLY
+    #define SPDLOG_INLINE inline
+#endif  // #ifdef SPDLOG_COMPILED_LIB
+
+#include <spdlog/fmt/fmt.h>
+
+#if !defined(SPDLOG_USE_STD_FORMAT) && \
+    FMT_VERSION >= 80000  // backward compatibility with fmt versions older than 8
+    #define SPDLOG_FMT_RUNTIME(format_string) fmt::runtime(format_string)
+    #define SPDLOG_FMT_STRING(format_string) FMT_STRING(format_string)
+    #if defined(SPDLOG_WCHAR_FILENAMES) || defined(SPDLOG_WCHAR_TO_UTF8_SUPPORT)
+        #include <spdlog/fmt/xchar.h>
+    #endif
+#else
+    #define SPDLOG_FMT_RUNTIME(format_string) format_string
+    #define SPDLOG_FMT_STRING(format_string) format_string
+#endif
+
+// visual studio up to 2013 does not support noexcept nor constexpr
+#if defined(_MSC_VER) && (_MSC_VER < 1900)
+    #define SPDLOG_NOEXCEPT _NOEXCEPT
+    #define SPDLOG_CONSTEXPR
+#else
+    #define SPDLOG_NOEXCEPT noexcept
+    #define SPDLOG_CONSTEXPR constexpr
+#endif
+
+// If building with std::format, can just use constexpr, otherwise if building with fmt
+// SPDLOG_CONSTEXPR_FUNC needs to be set the same as FMT_CONSTEXPR to avoid situations where
+// a constexpr function in spdlog could end up calling a non-constexpr function in fmt
+// depending on the compiler
+// If fmt determines it can't use constexpr, we should inline the function instead
+#ifdef SPDLOG_USE_STD_FORMAT
+    #define SPDLOG_CONSTEXPR_FUNC constexpr
+#else  // Being built with fmt
+    #if FMT_USE_CONSTEXPR
+        #define SPDLOG_CONSTEXPR_FUNC FMT_CONSTEXPR
+    #else
+        #define SPDLOG_CONSTEXPR_FUNC inline
+    #endif
+#endif
+
+#if defined(__GNUC__) || defined(__clang__)
+    #define SPDLOG_DEPRECATED __attribute__((deprecated))
+#elif defined(_MSC_VER)
+    #define SPDLOG_DEPRECATED __declspec(deprecated)
+#else
+    #define SPDLOG_DEPRECATED
+#endif
+
+// disable thread local on msvc 2013
+#ifndef SPDLOG_NO_TLS
+    #if (defined(_MSC_VER) && (_MSC_VER < 1900)) || defined(__cplusplus_winrt)
+        #define SPDLOG_NO_TLS 1
+    #endif
+#endif
+
+#ifndef SPDLOG_FUNCTION
+    #define SPDLOG_FUNCTION static_cast<const char *>(__FUNCTION__)
+#endif
+
+#ifdef SPDLOG_NO_EXCEPTIONS
+    #define SPDLOG_TRY
+    #define SPDLOG_THROW(ex)                               \
+        do {                                               \
+            printf("spdlog fatal error: %s\n", ex.what()); \
+            std::abort();                                  \
+        } while (0)
+    #define SPDLOG_CATCH_STD
+#else
+    #define SPDLOG_TRY try
+    #define SPDLOG_THROW(ex) throw(ex)
+    #define SPDLOG_CATCH_STD             \
+        catch (const std::exception &) { \
+        }
+#endif
+
+namespace spdlog {
+
+class formatter;
+
+namespace sinks {
+class sink;
+}
+
+#if defined(_WIN32) && defined(SPDLOG_WCHAR_FILENAMES)
+using filename_t = std::wstring;
+    // allow macro expansion to occur in SPDLOG_FILENAME_T
+    #define SPDLOG_FILENAME_T_INNER(s) L##s
+    #define SPDLOG_FILENAME_T(s) SPDLOG_FILENAME_T_INNER(s)
+#else
+using filename_t = std::string;
+    #define SPDLOG_FILENAME_T(s) s
+#endif
+
+using log_clock = std::chrono::system_clock;
+using sink_ptr = std::shared_ptr<sinks::sink>;
+using sinks_init_list = std::initializer_list<sink_ptr>;
+using err_handler = std::function<void(const std::string &err_msg)>;
+#ifdef SPDLOG_USE_STD_FORMAT
+namespace fmt_lib = std;
+
+using string_view_t = std::string_view;
+using memory_buf_t = std::string;
+
+template <typename... Args>
+    #if __cpp_lib_format >= 202207L
+using format_string_t = std::format_string<Args...>;
+    #else
+using format_string_t = std::string_view;
+    #endif
+
+template <class T, class Char = char>
+struct is_convertible_to_basic_format_string
+    : std::integral_constant<bool, std::is_convertible<T, std::basic_string_view<Char>>::value> {};
+
+    #if defined(SPDLOG_WCHAR_FILENAMES) || defined(SPDLOG_WCHAR_TO_UTF8_SUPPORT)
+using wstring_view_t = std::wstring_view;
+using wmemory_buf_t = std::wstring;
+
+template <typename... Args>
+        #if __cpp_lib_format >= 202207L
+using wformat_string_t = std::wformat_string<Args...>;
+        #else
+using wformat_string_t = std::wstring_view;
+        #endif
+    #endif
+    #define SPDLOG_BUF_TO_STRING(x) x
+#else  // use fmt lib instead of std::format
+namespace fmt_lib = fmt;
+
+using string_view_t = fmt::basic_string_view<char>;
+using memory_buf_t = fmt::basic_memory_buffer<char, 250>;
+
+template <typename... Args>
+using format_string_t = fmt::format_string<Args...>;
+
+template <class T>
+using remove_cvref_t = typename std::remove_cv<typename std::remove_reference<T>::type>::type;
+
+template <typename Char>
+    #if FMT_VERSION >= 90101
+using fmt_runtime_string = fmt::runtime_format_string<Char>;
+    #else
+using fmt_runtime_string = fmt::basic_runtime<Char>;
+    #endif
+
+// clang doesn't like SFINAE disabled constructor in std::is_convertible<> so have to repeat the
+// condition from basic_format_string here, in addition, fmt::basic_runtime<Char> is only
+// convertible to basic_format_string<Char> but not basic_string_view<Char>
+template <class T, class Char = char>
+struct is_convertible_to_basic_format_string
+    : std::integral_constant<bool,
+                             std::is_convertible<T, fmt::basic_string_view<Char>>::value ||
+                                 std::is_same<remove_cvref_t<T>, fmt_runtime_string<Char>>::value> {
+};
+
+    #if defined(SPDLOG_WCHAR_FILENAMES) || defined(SPDLOG_WCHAR_TO_UTF8_SUPPORT)
+using wstring_view_t = fmt::basic_string_view<wchar_t>;
+using wmemory_buf_t = fmt::basic_memory_buffer<wchar_t, 250>;
+
+template <typename... Args>
+using wformat_string_t = fmt::wformat_string<Args...>;
+    #endif
+    #define SPDLOG_BUF_TO_STRING(x) fmt::to_string(x)
+#endif
+
+#ifdef SPDLOG_WCHAR_TO_UTF8_SUPPORT
+    #ifndef _WIN32
+        #error SPDLOG_WCHAR_TO_UTF8_SUPPORT only supported on windows
+    #endif  // _WIN32
+#endif      // SPDLOG_WCHAR_TO_UTF8_SUPPORT
+
+template <class T>
+struct is_convertible_to_any_format_string
+    : std::integral_constant<bool,
+                             is_convertible_to_basic_format_string<T, char>::value ||
+                                 is_convertible_to_basic_format_string<T, wchar_t>::value> {};
+
+#if defined(SPDLOG_NO_ATOMIC_LEVELS)
+using level_t = details::null_atomic_int;
+#else
+using level_t = std::atomic<int>;
+#endif
+
+#define SPDLOG_LEVEL_TRACE 0
+#define SPDLOG_LEVEL_DEBUG 1
+#define SPDLOG_LEVEL_INFO 2
+#define SPDLOG_LEVEL_WARN 3
+#define SPDLOG_LEVEL_ERROR 4
+#define SPDLOG_LEVEL_CRITICAL 5
+#define SPDLOG_LEVEL_OFF 6
+
+#if !defined(SPDLOG_ACTIVE_LEVEL)
+    #define SPDLOG_ACTIVE_LEVEL SPDLOG_LEVEL_INFO
+#endif
+
+// Log level enum
+namespace level {
+enum level_enum : int {
+    trace = SPDLOG_LEVEL_TRACE,
+    debug = SPDLOG_LEVEL_DEBUG,
+    info = SPDLOG_LEVEL_INFO,
+    warn = SPDLOG_LEVEL_WARN,
+    err = SPDLOG_LEVEL_ERROR,
+    critical = SPDLOG_LEVEL_CRITICAL,
+    off = SPDLOG_LEVEL_OFF,
+    n_levels
+};
+
+#define SPDLOG_LEVEL_NAME_TRACE spdlog::string_view_t("trace", 5)
+#define SPDLOG_LEVEL_NAME_DEBUG spdlog::string_view_t("debug", 5)
+#define SPDLOG_LEVEL_NAME_INFO spdlog::string_view_t("info", 4)
+#define SPDLOG_LEVEL_NAME_WARNING spdlog::string_view_t("warning", 7)
+#define SPDLOG_LEVEL_NAME_ERROR spdlog::string_view_t("error", 5)
+#define SPDLOG_LEVEL_NAME_CRITICAL spdlog::string_view_t("critical", 8)
+#define SPDLOG_LEVEL_NAME_OFF spdlog::string_view_t("off", 3)
+
+#if !defined(SPDLOG_LEVEL_NAMES)
+    #define SPDLOG_LEVEL_NAMES                                                                  \
+        {                                                                                       \
+            SPDLOG_LEVEL_NAME_TRACE, SPDLOG_LEVEL_NAME_DEBUG, SPDLOG_LEVEL_NAME_INFO,           \
+                SPDLOG_LEVEL_NAME_WARNING, SPDLOG_LEVEL_NAME_ERROR, SPDLOG_LEVEL_NAME_CRITICAL, \
+                SPDLOG_LEVEL_NAME_OFF                                                           \
+        }
+#endif
+
+#if !defined(SPDLOG_SHORT_LEVEL_NAMES)
+
+    #define SPDLOG_SHORT_LEVEL_NAMES \
+        { "T", "D", "I", "W", "E", "C", "O" }
+#endif
+
+SPDLOG_API const string_view_t &to_string_view(spdlog::level::level_enum l) SPDLOG_NOEXCEPT;
+SPDLOG_API const char *to_short_c_str(spdlog::level::level_enum l) SPDLOG_NOEXCEPT;
+SPDLOG_API spdlog::level::level_enum from_str(const std::string &name) SPDLOG_NOEXCEPT;
+
+}  // namespace level
+
+//
+// Color mode used by sinks with color support.
+//
+enum class color_mode { always, automatic, never };
+
+//
+// Pattern time - specific time getting to use for pattern_formatter.
+// local time by default
+//
+enum class pattern_time_type {
+    local,  // log localtime
+    utc     // log utc
+};
+
+//
+// Log exception
+//
+class SPDLOG_API spdlog_ex : public std::exception {
+public:
+    explicit spdlog_ex(std::string msg);
+    spdlog_ex(const std::string &msg, int last_errno);
+    const char *what() const SPDLOG_NOEXCEPT override;
+
+private:
+    std::string msg_;
+};
+
+[[noreturn]] SPDLOG_API void throw_spdlog_ex(const std::string &msg, int last_errno);
+[[noreturn]] SPDLOG_API void throw_spdlog_ex(std::string msg);
+
+struct source_loc {
+    SPDLOG_CONSTEXPR source_loc() = default;
+    SPDLOG_CONSTEXPR source_loc(const char *filename_in, int line_in, const char *funcname_in)
+        : filename{filename_in},
+          line{line_in},
+          funcname{funcname_in} {}
+
+    SPDLOG_CONSTEXPR bool empty() const SPDLOG_NOEXCEPT { return line <= 0; }
+    const char *filename{nullptr};
+    int line{0};
+    const char *funcname{nullptr};
+};
+
+struct file_event_handlers {
+    file_event_handlers()
+        : before_open(nullptr),
+          after_open(nullptr),
+          before_close(nullptr),
+          after_close(nullptr) {}
+
+    std::function<void(const filename_t &filename)> before_open;
+    std::function<void(const filename_t &filename, std::FILE *file_stream)> after_open;
+    std::function<void(const filename_t &filename, std::FILE *file_stream)> before_close;
+    std::function<void(const filename_t &filename)> after_close;
+};
+
+namespace details {
+
+// to_string_view
+
+SPDLOG_CONSTEXPR_FUNC spdlog::string_view_t to_string_view(const memory_buf_t &buf)
+    SPDLOG_NOEXCEPT {
+    return spdlog::string_view_t{buf.data(), buf.size()};
+}
+
+SPDLOG_CONSTEXPR_FUNC spdlog::string_view_t to_string_view(spdlog::string_view_t str)
+    SPDLOG_NOEXCEPT {
+    return str;
+}
+
+#if defined(SPDLOG_WCHAR_FILENAMES) || defined(SPDLOG_WCHAR_TO_UTF8_SUPPORT)
+SPDLOG_CONSTEXPR_FUNC spdlog::wstring_view_t to_string_view(const wmemory_buf_t &buf)
+    SPDLOG_NOEXCEPT {
+    return spdlog::wstring_view_t{buf.data(), buf.size()};
+}
+
+SPDLOG_CONSTEXPR_FUNC spdlog::wstring_view_t to_string_view(spdlog::wstring_view_t str)
+    SPDLOG_NOEXCEPT {
+    return str;
+}
+#endif
+
+#if defined(SPDLOG_USE_STD_FORMAT) &&  __cpp_lib_format >= 202207L
+template <typename T, typename... Args>
+SPDLOG_CONSTEXPR_FUNC std::basic_string_view<T> to_string_view(
+    std::basic_format_string<T, Args...> fmt) SPDLOG_NOEXCEPT {
+    return fmt.get();
+}
+#endif
+
+// make_unique support for pre c++14
+#if __cplusplus >= 201402L  // C++14 and beyond
+using std::enable_if_t;
+using std::make_unique;
+#else
+template <bool B, class T = void>
+using enable_if_t = typename std::enable_if<B, T>::type;
+
+template <typename T, typename... Args>
+std::unique_ptr<T> make_unique(Args &&...args) {
+    static_assert(!std::is_array<T>::value, "arrays not supported");
+    return std::unique_ptr<T>(new T(std::forward<Args>(args)...));
+}
+#endif
+
+// to avoid useless casts (see https://github.com/nlohmann/json/issues/2893#issuecomment-889152324)
+template <typename T, typename U, enable_if_t<!std::is_same<T, U>::value, int> = 0>
+constexpr T conditional_static_cast(U value) {
+    return static_cast<T>(value);
+}
+
+template <typename T, typename U, enable_if_t<std::is_same<T, U>::value, int> = 0>
+constexpr T conditional_static_cast(U value) {
+    return value;
+}
+
+}  // namespace details
+}  // namespace spdlog
+
+#ifdef SPDLOG_HEADER_ONLY
+    #include "common-inl.h"
+#endif

spdlog/details/backtracer-inl.h

@@ -0,0 +1,63 @@
+// Copyright(c) 2015-present, Gabi Melman & spdlog contributors.
+// Distributed under the MIT License (http://opensource.org/licenses/MIT)
+
+#pragma once
+
+#ifndef SPDLOG_HEADER_ONLY
+    #include <spdlog/details/backtracer.h>
+#endif
+namespace spdlog {
+namespace details {
+SPDLOG_INLINE backtracer::backtracer(const backtracer &other) {
+    std::lock_guard<std::mutex> lock(other.mutex_);
+    enabled_ = other.enabled();
+    messages_ = other.messages_;
+}
+
+SPDLOG_INLINE backtracer::backtracer(backtracer &&other) SPDLOG_NOEXCEPT {
+    std::lock_guard<std::mutex> lock(other.mutex_);
+    enabled_ = other.enabled();
+    messages_ = std::move(other.messages_);
+}
+
+SPDLOG_INLINE backtracer &backtracer::operator=(backtracer other) {
+    std::lock_guard<std::mutex> lock(mutex_);
+    enabled_ = other.enabled();
+    messages_ = std::move(other.messages_);
+    return *this;
+}
+
+SPDLOG_INLINE void backtracer::enable(size_t size) {
+    std::lock_guard<std::mutex> lock{mutex_};
+    enabled_.store(true, std::memory_order_relaxed);
+    messages_ = circular_q<log_msg_buffer>{size};
+}
+
+SPDLOG_INLINE void backtracer::disable() {
+    std::lock_guard<std::mutex> lock{mutex_};
+    enabled_.store(false, std::memory_order_relaxed);
+}
+
+SPDLOG_INLINE bool backtracer::enabled() const { return enabled_.load(std::memory_order_relaxed); }
+
+SPDLOG_INLINE void backtracer::push_back(const log_msg &msg) {
+    std::lock_guard<std::mutex> lock{mutex_};
+    messages_.push_back(log_msg_buffer{msg});
+}
+
+SPDLOG_INLINE bool backtracer::empty() const {
+    std::lock_guard<std::mutex> lock{mutex_};
+    return messages_.empty();
+}
+
+// pop all items in the q and apply the given fun on each of them.
+SPDLOG_INLINE void backtracer::foreach_pop(std::function<void(const details::log_msg &)> fun) {
+    std::lock_guard<std::mutex> lock{mutex_};
+    while (!messages_.empty()) {
+        auto &front_msg = messages_.front();
+        fun(front_msg);
+        messages_.pop_front();
+    }
+}
+}  // namespace details
+}  // namespace spdlog

spdlog/details/backtracer.h

@@ -0,0 +1,45 @@
+// Copyright(c) 2015-present, Gabi Melman & spdlog contributors.
+// Distributed under the MIT License (http://opensource.org/licenses/MIT)
+
+#pragma once
+
+#include <spdlog/details/circular_q.h>
+#include <spdlog/details/log_msg_buffer.h>
+
+#include <atomic>
+#include <functional>
+#include <mutex>
+
+// Store log messages in circular buffer.
+// Useful for storing debug data in case of error/warning happens.
+
+namespace spdlog {
+namespace details {
+class SPDLOG_API backtracer {
+    mutable std::mutex mutex_;
+    std::atomic<bool> enabled_{false};
+    circular_q<log_msg_buffer> messages_;
+
+public:
+    backtracer() = default;
+    backtracer(const backtracer &other);
+
+    backtracer(backtracer &&other) SPDLOG_NOEXCEPT;
+    backtracer &operator=(backtracer other);
+
+    void enable(size_t size);
+    void disable();
+    bool enabled() const;
+    void push_back(const log_msg &msg);
+    bool empty() const;
+
+    // pop all items in the q and apply the given fun on each of them.
+    void foreach_pop(std::function<void(const details::log_msg &)> fun);
+};
+
+}  // namespace details
+}  // namespace spdlog
+
+#ifdef SPDLOG_HEADER_ONLY
+    #include "backtracer-inl.h"
+#endif

spdlog/details/circular_q.h

@@ -0,0 +1,115 @@
+// Copyright(c) 2015-present, Gabi Melman & spdlog contributors.
+// Distributed under the MIT License (http://opensource.org/licenses/MIT)
+
+// circular q view of std::vector.
+#pragma once
+
+#include <cassert>
+#include <vector>
+
+#include "spdlog/common.h"
+
+namespace spdlog {
+namespace details {
+template <typename T>
+class circular_q {
+    size_t max_items_ = 0;
+    typename std::vector<T>::size_type head_ = 0;
+    typename std::vector<T>::size_type tail_ = 0;
+    size_t overrun_counter_ = 0;
+    std::vector<T> v_;
+
+public:
+    using value_type = T;
+
+    // empty ctor - create a disabled queue with no elements allocated at all
+    circular_q() = default;
+
+    explicit circular_q(size_t max_items)
+        : max_items_(max_items + 1)  // one item is reserved as marker for full q
+          ,
+          v_(max_items_) {}
+
+    circular_q(const circular_q &) = default;
+    circular_q &operator=(const circular_q &) = default;
+
+    // move cannot be default,
+    // since we need to reset head_, tail_, etc to zero in the moved object
+    circular_q(circular_q &&other) SPDLOG_NOEXCEPT { copy_moveable(std::move(other)); }
+
+    circular_q &operator=(circular_q &&other) SPDLOG_NOEXCEPT {
+        copy_moveable(std::move(other));
+        return *this;
+    }
+
+    // push back, overrun (oldest) item if no room left
+    void push_back(T &&item) {
+        if (max_items_ > 0) {
+            v_[tail_] = std::move(item);
+            tail_ = (tail_ + 1) % max_items_;
+
+            if (tail_ == head_)  // overrun last item if full
+            {
+                head_ = (head_ + 1) % max_items_;
+                ++overrun_counter_;
+            }
+        }
+    }
+
+    // Return reference to the front item.
+    // If there are no elements in the container, the behavior is undefined.
+    const T &front() const { return v_[head_]; }
+
+    T &front() { return v_[head_]; }
+
+    // Return number of elements actually stored
+    size_t size() const {
+        if (tail_ >= head_) {
+            return tail_ - head_;
+        } else {
+            return max_items_ - (head_ - tail_);
+        }
+    }
+
+    // Return const reference to item by index.
+    // If index is out of range 0…size()-1, the behavior is undefined.
+    const T &at(size_t i) const {
+        assert(i < size());
+        return v_[(head_ + i) % max_items_];
+    }
+
+    // Pop item from front.
+    // If there are no elements in the container, the behavior is undefined.
+    void pop_front() { head_ = (head_ + 1) % max_items_; }
+
+    bool empty() const { return tail_ == head_; }
+
+    bool full() const {
+        // head is ahead of the tail by 1
+        if (max_items_ > 0) {
+            return ((tail_ + 1) % max_items_) == head_;
+        }
+        return false;
+    }
+
+    size_t overrun_counter() const { return overrun_counter_; }
+
+    void reset_overrun_counter() { overrun_counter_ = 0; }
+
+private:
+    // copy from other&& and reset it to disabled state
+    void copy_moveable(circular_q &&other) SPDLOG_NOEXCEPT {
+        max_items_ = other.max_items_;
+        head_ = other.head_;
+        tail_ = other.tail_;
+        overrun_counter_ = other.overrun_counter_;
+        v_ = std::move(other.v_);
+
+        // put &&other in disabled, but valid state
+        other.max_items_ = 0;
+        other.head_ = other.tail_ = 0;
+        other.overrun_counter_ = 0;
+    }
+};
+}  // namespace details
+}  // namespace spdlog

spdlog/details/console_globals.h

@@ -0,0 +1,28 @@
+// Copyright(c) 2015-present, Gabi Melman & spdlog contributors.
+// Distributed under the MIT License (http://opensource.org/licenses/MIT)
+
+#pragma once
+
+#include <mutex>
+#include <spdlog/details/null_mutex.h>
+
+namespace spdlog {
+namespace details {
+
+struct console_mutex {
+    using mutex_t = std::mutex;
+    static mutex_t &mutex() {
+        static mutex_t s_mutex;
+        return s_mutex;
+    }
+};
+
+struct console_nullmutex {
+    using mutex_t = null_mutex;
+    static mutex_t &mutex() {
+        static mutex_t s_mutex;
+        return s_mutex;
+    }
+};
+}  // namespace details
+}  // namespace spdlog

spdlog/details/file_helper-inl.h

@@ -0,0 +1,153 @@
+// Copyright(c) 2015-present, Gabi Melman & spdlog contributors.
+// Distributed under the MIT License (http://opensource.org/licenses/MIT)
+
+#pragma once
+
+#ifndef SPDLOG_HEADER_ONLY
+    #include <spdlog/details/file_helper.h>
+#endif
+
+#include <spdlog/common.h>
+#include <spdlog/details/os.h>
+
+#include <cerrno>
+#include <chrono>
+#include <cstdio>
+#include <string>
+#include <thread>
+#include <tuple>
+
+namespace spdlog {
+namespace details {
+
+SPDLOG_INLINE file_helper::file_helper(const file_event_handlers &event_handlers)
+    : event_handlers_(event_handlers) {}
+
+SPDLOG_INLINE file_helper::~file_helper() { close(); }
+
+SPDLOG_INLINE void file_helper::open(const filename_t &fname, bool truncate) {
+    close();
+    filename_ = fname;
+
+    auto *mode = SPDLOG_FILENAME_T("ab");
+    auto *trunc_mode = SPDLOG_FILENAME_T("wb");
+
+    if (event_handlers_.before_open) {
+        event_handlers_.before_open(filename_);
+    }
+    for (int tries = 0; tries < open_tries_; ++tries) {
+        // create containing folder if not exists already.
+        os::create_dir(os::dir_name(fname));
+        if (truncate) {
+            // Truncate by opening-and-closing a tmp file in "wb" mode, always
+            // opening the actual log-we-write-to in "ab" mode, since that
+            // interacts more politely with eternal processes that might
+            // rotate/truncate the file underneath us.
+            std::FILE *tmp;
+            if (os::fopen_s(&tmp, fname, trunc_mode)) {
+                continue;
+            }
+            std::fclose(tmp);
+        }
+        if (!os::fopen_s(&fd_, fname, mode)) {
+            if (event_handlers_.after_open) {
+                event_handlers_.after_open(filename_, fd_);
+            }
+            return;
+        }
+
+        details::os::sleep_for_millis(open_interval_);
+    }
+
+    throw_spdlog_ex("Failed opening file " + os::filename_to_str(filename_) + " for writing",
+                    errno);
+}
+
+SPDLOG_INLINE void file_helper::reopen(bool truncate) {
+    if (filename_.empty()) {
+        throw_spdlog_ex("Failed re opening file - was not opened before");
+    }
+    this->open(filename_, truncate);
+}
+
+SPDLOG_INLINE void file_helper::flush() {
+    if (std::fflush(fd_) != 0) {
+        throw_spdlog_ex("Failed flush to file " + os::filename_to_str(filename_), errno);
+    }
+}
+
+SPDLOG_INLINE void file_helper::sync() {
+    if (!os::fsync(fd_)) {
+        throw_spdlog_ex("Failed to fsync file " + os::filename_to_str(filename_), errno);
+    }
+}
+
+SPDLOG_INLINE void file_helper::close() {
+    if (fd_ != nullptr) {
+        if (event_handlers_.before_close) {
+            event_handlers_.before_close(filename_, fd_);
+        }
+
+        std::fclose(fd_);
+        fd_ = nullptr;
+
+        if (event_handlers_.after_close) {
+            event_handlers_.after_close(filename_);
+        }
+    }
+}
+
+SPDLOG_INLINE void file_helper::write(const memory_buf_t &buf) {
+    if (fd_ == nullptr) return;
+    size_t msg_size = buf.size();
+    auto data = buf.data();
+
+    if (!details::os::fwrite_bytes(data, msg_size, fd_)) {
+        throw_spdlog_ex("Failed writing to file " + os::filename_to_str(filename_), errno);
+    }
+}
+
+SPDLOG_INLINE size_t file_helper::size() const {
+    if (fd_ == nullptr) {
+        throw_spdlog_ex("Cannot use size() on closed file " + os::filename_to_str(filename_));
+    }
+    return os::filesize(fd_);
+}
+
+SPDLOG_INLINE const filename_t &file_helper::filename() const { return filename_; }
+
+//
+// return file path and its extension:
+//
+// "mylog.txt" => ("mylog", ".txt")
+// "mylog" => ("mylog", "")
+// "mylog." => ("mylog.", "")
+// "/dir1/dir2/mylog.txt" => ("/dir1/dir2/mylog", ".txt")
+//
+// the starting dot in filenames is ignored (hidden files):
+//
+// ".mylog" => (".mylog". "")
+// "my_folder/.mylog" => ("my_folder/.mylog", "")
+// "my_folder/.mylog.txt" => ("my_folder/.mylog", ".txt")
+SPDLOG_INLINE std::tuple<filename_t, filename_t> file_helper::split_by_extension(
+    const filename_t &fname) {
+    auto ext_index = fname.rfind('.');
+
+    // no valid extension found - return whole path and empty string as
+    // extension
+    if (ext_index == filename_t::npos || ext_index == 0 || ext_index == fname.size() - 1) {
+        return std::make_tuple(fname, filename_t());
+    }
+
+    // treat cases like "/etc/rc.d/somelogfile or "/abc/.hiddenfile"
+    auto folder_index = fname.find_last_of(details::os::folder_seps_filename);
+    if (folder_index != filename_t::npos && folder_index >= ext_index - 1) {
+        return std::make_tuple(fname, filename_t());
+    }
+
+    // finally - return a valid base and extension tuple
+    return std::make_tuple(fname.substr(0, ext_index), fname.substr(ext_index));
+}
+
+}  // namespace details
+}  // namespace spdlog

spdlog/details/file_helper.h

@@ -0,0 +1,61 @@
+// Copyright(c) 2015-present, Gabi Melman & spdlog contributors.
+// Distributed under the MIT License (http://opensource.org/licenses/MIT)
+
+#pragma once
+
+#include <spdlog/common.h>
+#include <tuple>
+
+namespace spdlog {
+namespace details {
+
+// Helper class for file sinks.
+// When failing to open a file, retry several times(5) with a delay interval(10 ms).
+// Throw spdlog_ex exception on errors.
+
+class SPDLOG_API file_helper {
+public:
+    file_helper() = default;
+    explicit file_helper(const file_event_handlers &event_handlers);
+
+    file_helper(const file_helper &) = delete;
+    file_helper &operator=(const file_helper &) = delete;
+    ~file_helper();
+
+    void open(const filename_t &fname, bool truncate = false);
+    void reopen(bool truncate);
+    void flush();
+    void sync();
+    void close();
+    void write(const memory_buf_t &buf);
+    size_t size() const;
+    const filename_t &filename() const;
+
+    //
+    // return file path and its extension:
+    //
+    // "mylog.txt" => ("mylog", ".txt")
+    // "mylog" => ("mylog", "")
+    // "mylog." => ("mylog.", "")
+    // "/dir1/dir2/mylog.txt" => ("/dir1/dir2/mylog", ".txt")
+    //
+    // the starting dot in filenames is ignored (hidden files):
+    //
+    // ".mylog" => (".mylog". "")
+    // "my_folder/.mylog" => ("my_folder/.mylog", "")
+    // "my_folder/.mylog.txt" => ("my_folder/.mylog", ".txt")
+    static std::tuple<filename_t, filename_t> split_by_extension(const filename_t &fname);
+
+private:
+    const int open_tries_ = 5;
+    const unsigned int open_interval_ = 10;
+    std::FILE *fd_{nullptr};
+    filename_t filename_;
+    file_event_handlers event_handlers_;
+};
+}  // namespace details
+}  // namespace spdlog
+
+#ifdef SPDLOG_HEADER_ONLY
+    #include "file_helper-inl.h"
+#endif

spdlog/details/fmt_helper.h

@@ -0,0 +1,141 @@
+// Copyright(c) 2015-present, Gabi Melman & spdlog contributors.
+// Distributed under the MIT License (http://opensource.org/licenses/MIT)
+#pragma once
+
+#include <chrono>
+#include <iterator>
+#include <spdlog/common.h>
+#include <spdlog/fmt/fmt.h>
+#include <type_traits>
+
+#ifdef SPDLOG_USE_STD_FORMAT
+    #include <charconv>
+    #include <limits>
+#endif
+
+// Some fmt helpers to efficiently format and pad ints and strings
+namespace spdlog {
+namespace details {
+namespace fmt_helper {
+
+inline void append_string_view(spdlog::string_view_t view, memory_buf_t &dest) {
+    auto *buf_ptr = view.data();
+    dest.append(buf_ptr, buf_ptr + view.size());
+}
+
+#ifdef SPDLOG_USE_STD_FORMAT
+template <typename T>
+inline void append_int(T n, memory_buf_t &dest) {
+    // Buffer should be large enough to hold all digits (digits10 + 1) and a sign
+    SPDLOG_CONSTEXPR const auto BUF_SIZE = std::numeric_limits<T>::digits10 + 2;
+    char buf[BUF_SIZE];
+
+    auto [ptr, ec] = std::to_chars(buf, buf + BUF_SIZE, n, 10);
+    if (ec == std::errc()) {
+        dest.append(buf, ptr);
+    } else {
+        throw_spdlog_ex("Failed to format int", static_cast<int>(ec));
+    }
+}
+#else
+template <typename T>
+inline void append_int(T n, memory_buf_t &dest) {
+    fmt::format_int i(n);
+    dest.append(i.data(), i.data() + i.size());
+}
+#endif
+
+template <typename T>
+SPDLOG_CONSTEXPR_FUNC unsigned int count_digits_fallback(T n) {
+    // taken from fmt: https://github.com/fmtlib/fmt/blob/8.0.1/include/fmt/format.h#L899-L912
+    unsigned int count = 1;
+    for (;;) {
+        // Integer division is slow so do it for a group of four digits instead
+        // of for every digit. The idea comes from the talk by Alexandrescu
+        // "Three Optimization Tips for C++". See speed-test for a comparison.
+        if (n < 10) return count;
+        if (n < 100) return count + 1;
+        if (n < 1000) return count + 2;
+        if (n < 10000) return count + 3;
+        n /= 10000u;
+        count += 4;
+    }
+}
+
+template <typename T>
+inline unsigned int count_digits(T n) {
+    using count_type =
+        typename std::conditional<(sizeof(T) > sizeof(uint32_t)), uint64_t, uint32_t>::type;
+#ifdef SPDLOG_USE_STD_FORMAT
+    return count_digits_fallback(static_cast<count_type>(n));
+#else
+    return static_cast<unsigned int>(fmt::
+    // fmt 7.0.0 renamed the internal namespace to detail.
+    // See: https://github.com/fmtlib/fmt/issues/1538
+    #if FMT_VERSION < 70000
+                                         internal
+    #else
+                                         detail
+    #endif
+                                     ::count_digits(static_cast<count_type>(n)));
+#endif
+}
+
+inline void pad2(int n, memory_buf_t &dest) {
+    if (n >= 0 && n < 100)  // 0-99
+    {
+        dest.push_back(static_cast<char>('0' + n / 10));
+        dest.push_back(static_cast<char>('0' + n % 10));
+    } else  // unlikely, but just in case, let fmt deal with it
+    {
+        fmt_lib::format_to(std::back_inserter(dest), SPDLOG_FMT_STRING("{:02}"), n);
+    }
+}
+
+template <typename T>
+inline void pad_uint(T n, unsigned int width, memory_buf_t &dest) {
+    static_assert(std::is_unsigned<T>::value, "pad_uint must get unsigned T");
+    for (auto digits = count_digits(n); digits < width; digits++) {
+        dest.push_back('0');
+    }
+    append_int(n, dest);
+}
+
+template <typename T>
+inline void pad3(T n, memory_buf_t &dest) {
+    static_assert(std::is_unsigned<T>::value, "pad3 must get unsigned T");
+    if (n < 1000) {
+        dest.push_back(static_cast<char>(n / 100 + '0'));
+        n = n % 100;
+        dest.push_back(static_cast<char>((n / 10) + '0'));
+        dest.push_back(static_cast<char>((n % 10) + '0'));
+    } else {
+        append_int(n, dest);
+    }
+}
+
+template <typename T>
+inline void pad6(T n, memory_buf_t &dest) {
+    pad_uint(n, 6, dest);
+}
+
+template <typename T>
+inline void pad9(T n, memory_buf_t &dest) {
+    pad_uint(n, 9, dest);
+}
+
+// return fraction of a second of the given time_point.
+// e.g.
+// fraction<std::milliseconds>(tp) -> will return the millis part of the second
+template <typename ToDuration>
+inline ToDuration time_fraction(log_clock::time_point tp) {
+    using std::chrono::duration_cast;
+    using std::chrono::seconds;
+    auto duration = tp.time_since_epoch();
+    auto secs = duration_cast<seconds>(duration);
+    return duration_cast<ToDuration>(duration) - duration_cast<ToDuration>(secs);
+}
+
+}  // namespace fmt_helper
+}  // namespace details
+}  // namespace spdlog

spdlog/details/log_msg-inl.h

@@ -0,0 +1,44 @@
+// Copyright(c) 2015-present, Gabi Melman & spdlog contributors.
+// Distributed under the MIT License (http://opensource.org/licenses/MIT)
+
+#pragma once
+
+#ifndef SPDLOG_HEADER_ONLY
+    #include <spdlog/details/log_msg.h>
+#endif
+
+#include <spdlog/details/os.h>
+
+namespace spdlog {
+namespace details {
+
+SPDLOG_INLINE log_msg::log_msg(spdlog::log_clock::time_point log_time,
+                               spdlog::source_loc loc,
+                               string_view_t a_logger_name,
+                               spdlog::level::level_enum lvl,
+                               spdlog::string_view_t msg)
+    : logger_name(a_logger_name),
+      level(lvl),
+      time(log_time)
+#ifndef SPDLOG_NO_THREAD_ID
+      ,
+      thread_id(os::thread_id())
+#endif
+      ,
+      source(loc),
+      payload(msg) {
+}
+
+SPDLOG_INLINE log_msg::log_msg(spdlog::source_loc loc,
+                               string_view_t a_logger_name,
+                               spdlog::level::level_enum lvl,
+                               spdlog::string_view_t msg)
+    : log_msg(os::now(), loc, a_logger_name, lvl, msg) {}
+
+SPDLOG_INLINE log_msg::log_msg(string_view_t a_logger_name,
+                               spdlog::level::level_enum lvl,
+                               spdlog::string_view_t msg)
+    : log_msg(os::now(), source_loc{}, a_logger_name, lvl, msg) {}
+
+}  // namespace details
+}  // namespace spdlog

spdlog/details/log_msg.h

@@ -0,0 +1,40 @@
+// Copyright(c) 2015-present, Gabi Melman & spdlog contributors.
+// Distributed under the MIT License (http://opensource.org/licenses/MIT)
+
+#pragma once
+
+#include <spdlog/common.h>
+#include <string>
+
+namespace spdlog {
+namespace details {
+struct SPDLOG_API log_msg {
+    log_msg() = default;
+    log_msg(log_clock::time_point log_time,
+            source_loc loc,
+            string_view_t logger_name,
+            level::level_enum lvl,
+            string_view_t msg);
+    log_msg(source_loc loc, string_view_t logger_name, level::level_enum lvl, string_view_t msg);
+    log_msg(string_view_t logger_name, level::level_enum lvl, string_view_t msg);
+    log_msg(const log_msg &other) = default;
+    log_msg &operator=(const log_msg &other) = default;
+
+    string_view_t logger_name;
+    level::level_enum level{level::off};
+    log_clock::time_point time;
+    size_t thread_id{0};
+
+    // wrapping the formatted text with color (updated by pattern_formatter).
+    mutable size_t color_range_start{0};
+    mutable size_t color_range_end{0};
+
+    source_loc source;
+    string_view_t payload;
+};
+}  // namespace details
+}  // namespace spdlog
+
+#ifdef SPDLOG_HEADER_ONLY
+    #include "log_msg-inl.h"
+#endif

spdlog/details/log_msg_buffer-inl.h

@@ -0,0 +1,54 @@
+// Copyright(c) 2015-present, Gabi Melman & spdlog contributors.
+// Distributed under the MIT License (http://opensource.org/licenses/MIT)
+
+#pragma once
+
+#ifndef SPDLOG_HEADER_ONLY
+    #include <spdlog/details/log_msg_buffer.h>
+#endif
+
+namespace spdlog {
+namespace details {
+
+SPDLOG_INLINE log_msg_buffer::log_msg_buffer(const log_msg &orig_msg)
+    : log_msg{orig_msg} {
+    buffer.append(logger_name.begin(), logger_name.end());
+    buffer.append(payload.begin(), payload.end());
+    update_string_views();
+}
+
+SPDLOG_INLINE log_msg_buffer::log_msg_buffer(const log_msg_buffer &other)
+    : log_msg{other} {
+    buffer.append(logger_name.begin(), logger_name.end());
+    buffer.append(payload.begin(), payload.end());
+    update_string_views();
+}
+
+SPDLOG_INLINE log_msg_buffer::log_msg_buffer(log_msg_buffer &&other) SPDLOG_NOEXCEPT
+    : log_msg{other},
+      buffer{std::move(other.buffer)} {
+    update_string_views();
+}
+
+SPDLOG_INLINE log_msg_buffer &log_msg_buffer::operator=(const log_msg_buffer &other) {
+    log_msg::operator=(other);
+    buffer.clear();
+    buffer.append(other.buffer.data(), other.buffer.data() + other.buffer.size());
+    update_string_views();
+    return *this;
+}
+
+SPDLOG_INLINE log_msg_buffer &log_msg_buffer::operator=(log_msg_buffer &&other) SPDLOG_NOEXCEPT {
+    log_msg::operator=(other);
+    buffer = std::move(other.buffer);
+    update_string_views();
+    return *this;
+}
+
+SPDLOG_INLINE void log_msg_buffer::update_string_views() {
+    logger_name = string_view_t{buffer.data(), logger_name.size()};
+    payload = string_view_t{buffer.data() + logger_name.size(), payload.size()};
+}
+
+}  // namespace details
+}  // namespace spdlog

spdlog/details/log_msg_buffer.h

@@ -0,0 +1,32 @@
+// Copyright(c) 2015-present, Gabi Melman & spdlog contributors.
+// Distributed under the MIT License (http://opensource.org/licenses/MIT)
+
+#pragma once
+
+#include <spdlog/details/log_msg.h>
+
+namespace spdlog {
+namespace details {
+
+// Extend log_msg with internal buffer to store its payload.
+// This is needed since log_msg holds string_views that points to stack data.
+
+class SPDLOG_API log_msg_buffer : public log_msg {
+    memory_buf_t buffer;
+    void update_string_views();
+
+public:
+    log_msg_buffer() = default;
+    explicit log_msg_buffer(const log_msg &orig_msg);
+    log_msg_buffer(const log_msg_buffer &other);
+    log_msg_buffer(log_msg_buffer &&other) SPDLOG_NOEXCEPT;
+    log_msg_buffer &operator=(const log_msg_buffer &other);
+    log_msg_buffer &operator=(log_msg_buffer &&other) SPDLOG_NOEXCEPT;
+};
+
+}  // namespace details
+}  // namespace spdlog
+
+#ifdef SPDLOG_HEADER_ONLY
+    #include "log_msg_buffer-inl.h"
+#endif

spdlog/details/mpmc_blocking_q.h

@@ -0,0 +1,177 @@
+// Copyright(c) 2015-present, Gabi Melman & spdlog contributors.
+// Distributed under the MIT License (http://opensource.org/licenses/MIT)
+
+#pragma once
+
+// multi producer-multi consumer blocking queue.
+// enqueue(..) - will block until room found to put the new message.
+// enqueue_nowait(..) - will return immediately with false if no room left in
+// the queue.
+// dequeue_for(..) - will block until the queue is not empty or timeout have
+// passed.
+
+#include <spdlog/details/circular_q.h>
+
+#include <atomic>
+#include <condition_variable>
+#include <mutex>
+
+namespace spdlog {
+namespace details {
+
+template <typename T>
+class mpmc_blocking_queue {
+public:
+    using item_type = T;
+    explicit mpmc_blocking_queue(size_t max_items)
+        : q_(max_items) {}
+
+#ifndef __MINGW32__
+    // try to enqueue and block if no room left
+    void enqueue(T &&item) {
+        {
+            std::unique_lock<std::mutex> lock(queue_mutex_);
+            pop_cv_.wait(lock, [this] { return !this->q_.full(); });
+            q_.push_back(std::move(item));
+        }
+        push_cv_.notify_one();
+    }
+
+    // enqueue immediately. overrun oldest message in the queue if no room left.
+    void enqueue_nowait(T &&item) {
+        {
+            std::unique_lock<std::mutex> lock(queue_mutex_);
+            q_.push_back(std::move(item));
+        }
+        push_cv_.notify_one();
+    }
+
+    void enqueue_if_have_room(T &&item) {
+        bool pushed = false;
+        {
+            std::unique_lock<std::mutex> lock(queue_mutex_);
+            if (!q_.full()) {
+                q_.push_back(std::move(item));
+                pushed = true;
+            }
+        }
+
+        if (pushed) {
+            push_cv_.notify_one();
+        } else {
+            ++discard_counter_;
+        }
+    }
+
+    // dequeue with a timeout.
+    // Return true, if succeeded dequeue item, false otherwise
+    bool dequeue_for(T &popped_item, std::chrono::milliseconds wait_duration) {
+        {
+            std::unique_lock<std::mutex> lock(queue_mutex_);
+            if (!push_cv_.wait_for(lock, wait_duration, [this] { return !this->q_.empty(); })) {
+                return false;
+            }
+            popped_item = std::move(q_.front());
+            q_.pop_front();
+        }
+        pop_cv_.notify_one();
+        return true;
+    }
+
+    // blocking dequeue without a timeout.
+    void dequeue(T &popped_item) {
+        {
+            std::unique_lock<std::mutex> lock(queue_mutex_);
+            push_cv_.wait(lock, [this] { return !this->q_.empty(); });
+            popped_item = std::move(q_.front());
+            q_.pop_front();
+        }
+        pop_cv_.notify_one();
+    }
+
+#else
+    // apparently mingw deadlocks if the mutex is released before cv.notify_one(),
+    // so release the mutex at the very end each function.
+
+    // try to enqueue and block if no room left
+    void enqueue(T &&item) {
+        std::unique_lock<std::mutex> lock(queue_mutex_);
+        pop_cv_.wait(lock, [this] { return !this->q_.full(); });
+        q_.push_back(std::move(item));
+        push_cv_.notify_one();
+    }
+
+    // enqueue immediately. overrun oldest message in the queue if no room left.
+    void enqueue_nowait(T &&item) {
+        std::unique_lock<std::mutex> lock(queue_mutex_);
+        q_.push_back(std::move(item));
+        push_cv_.notify_one();
+    }
+
+    void enqueue_if_have_room(T &&item) {
+        bool pushed = false;
+        std::unique_lock<std::mutex> lock(queue_mutex_);
+        if (!q_.full()) {
+            q_.push_back(std::move(item));
+            pushed = true;
+        }
+
+        if (pushed) {
+            push_cv_.notify_one();
+        } else {
+            ++discard_counter_;
+        }
+    }
+
+    // dequeue with a timeout.
+    // Return true, if succeeded dequeue item, false otherwise
+    bool dequeue_for(T &popped_item, std::chrono::milliseconds wait_duration) {
+        std::unique_lock<std::mutex> lock(queue_mutex_);
+        if (!push_cv_.wait_for(lock, wait_duration, [this] { return !this->q_.empty(); })) {
+            return false;
+        }
+        popped_item = std::move(q_.front());
+        q_.pop_front();
+        pop_cv_.notify_one();
+        return true;
+    }
+
+    // blocking dequeue without a timeout.
+    void dequeue(T &popped_item) {
+        std::unique_lock<std::mutex> lock(queue_mutex_);
+        push_cv_.wait(lock, [this] { return !this->q_.empty(); });
+        popped_item = std::move(q_.front());
+        q_.pop_front();
+        pop_cv_.notify_one();
+    }
+
+#endif
+
+    size_t overrun_counter() {
+        std::lock_guard<std::mutex> lock(queue_mutex_);
+        return q_.overrun_counter();
+    }
+
+    size_t discard_counter() { return discard_counter_.load(std::memory_order_relaxed); }
+
+    size_t size() {
+        std::lock_guard<std::mutex> lock(queue_mutex_);
+        return q_.size();
+    }
+
+    void reset_overrun_counter() {
+        std::lock_guard<std::mutex> lock(queue_mutex_);
+        q_.reset_overrun_counter();
+    }
+
+    void reset_discard_counter() { discard_counter_.store(0, std::memory_order_relaxed); }
+
+private:
+    std::mutex queue_mutex_;
+    std::condition_variable push_cv_;
+    std::condition_variable pop_cv_;
+    spdlog::details::circular_q<T> q_;
+    std::atomic<size_t> discard_counter_{0};
+};
+}  // namespace details
+}  // namespace spdlog

spdlog/details/null_mutex.h

@@ -0,0 +1,35 @@
+// Copyright(c) 2015-present, Gabi Melman & spdlog contributors.
+// Distributed under the MIT License (http://opensource.org/licenses/MIT)
+
+#pragma once
+
+#include <atomic>
+#include <utility>
+// null, no cost dummy "mutex" and dummy "atomic" int
+
+namespace spdlog {
+namespace details {
+struct null_mutex {
+    void lock() const {}
+    void unlock() const {}
+};
+
+struct null_atomic_int {
+    int value;
+    null_atomic_int() = default;
+
+    explicit null_atomic_int(int new_value)
+        : value(new_value) {}
+
+    int load(std::memory_order = std::memory_order_relaxed) const { return value; }
+
+    void store(int new_value, std::memory_order = std::memory_order_relaxed) { value = new_value; }
+
+    int exchange(int new_value, std::memory_order = std::memory_order_relaxed) {
+        std::swap(new_value, value);
+        return new_value;  // return value before the call
+    }
+};
+
+}  // namespace details
+}  // namespace spdlog

spdlog/details/os-inl.h

@@ -0,0 +1,606 @@
+// Copyright(c) 2015-present, Gabi Melman & spdlog contributors.
+// Distributed under the MIT License (http://opensource.org/licenses/MIT)
+
+#pragma once
+
+#ifndef SPDLOG_HEADER_ONLY
+    #include <spdlog/details/os.h>
+#endif
+
+#include <spdlog/common.h>
+
+#include <algorithm>
+#include <array>
+#include <chrono>
+#include <cstdio>
+#include <cstdlib>
+#include <cstring>
+#include <ctime>
+#include <string>
+#include <sys/stat.h>
+#include <sys/types.h>
+#include <thread>
+
+#ifdef _WIN32
+    #include <spdlog/details/windows_include.h>
+    #include <fileapi.h>  // for FlushFileBuffers
+    #include <io.h>       // for _get_osfhandle, _isatty, _fileno
+    #include <process.h>  // for _get_pid
+
+    #ifdef __MINGW32__
+        #include <share.h>
+    #endif
+
+    #if defined(SPDLOG_WCHAR_TO_UTF8_SUPPORT) || defined(SPDLOG_WCHAR_FILENAMES)
+        #include <cassert>
+        #include <limits>
+    #endif
+
+    #include <direct.h>  // for _mkdir/_wmkdir
+
+#else  // unix
+
+    #include <fcntl.h>
+    #include <unistd.h>
+
+    #ifdef __linux__
+        #include <sys/syscall.h>  //Use gettid() syscall under linux to get thread id
+
+    #elif defined(_AIX)
+        #include <pthread.h>  // for pthread_getthrds_np
+
+    #elif defined(__DragonFly__) || defined(__FreeBSD__)
+        #include <pthread_np.h>  // for pthread_getthreadid_np
+
+    #elif defined(__NetBSD__)
+        #include <lwp.h>  // for _lwp_self
+
+    #elif defined(__sun)
+        #include <thread.h>  // for thr_self
+    #endif
+
+#endif  // unix
+
+#if defined __APPLE__
+    #include <AvailabilityMacros.h>
+#endif
+
+#ifndef __has_feature           // Clang - feature checking macros.
+    #define __has_feature(x) 0  // Compatibility with non-clang compilers.
+#endif
+
+namespace spdlog {
+namespace details {
+namespace os {
+
+SPDLOG_INLINE spdlog::log_clock::time_point now() SPDLOG_NOEXCEPT {
+#if defined __linux__ && defined SPDLOG_CLOCK_COARSE
+    timespec ts;
+    ::clock_gettime(CLOCK_REALTIME_COARSE, &ts);
+    return std::chrono::time_point<log_clock, typename log_clock::duration>(
+        std::chrono::duration_cast<typename log_clock::duration>(
+            std::chrono::seconds(ts.tv_sec) + std::chrono::nanoseconds(ts.tv_nsec)));
+
+#else
+    return log_clock::now();
+#endif
+}
+SPDLOG_INLINE std::tm localtime(const std::time_t &time_tt) SPDLOG_NOEXCEPT {
+#ifdef _WIN32
+    std::tm tm;
+    ::localtime_s(&tm, &time_tt);
+#else
+    std::tm tm;
+    ::localtime_r(&time_tt, &tm);
+#endif
+    return tm;
+}
+
+SPDLOG_INLINE std::tm localtime() SPDLOG_NOEXCEPT {
+    std::time_t now_t = ::time(nullptr);
+    return localtime(now_t);
+}
+
+SPDLOG_INLINE std::tm gmtime(const std::time_t &time_tt) SPDLOG_NOEXCEPT {
+#ifdef _WIN32
+    std::tm tm;
+    ::gmtime_s(&tm, &time_tt);
+#else
+    std::tm tm;
+    ::gmtime_r(&time_tt, &tm);
+#endif
+    return tm;
+}
+
+SPDLOG_INLINE std::tm gmtime() SPDLOG_NOEXCEPT {
+    std::time_t now_t = ::time(nullptr);
+    return gmtime(now_t);
+}
+
+// fopen_s on non windows for writing
+SPDLOG_INLINE bool fopen_s(FILE **fp, const filename_t &filename, const filename_t &mode) {
+#ifdef _WIN32
+    #ifdef SPDLOG_WCHAR_FILENAMES
+    *fp = ::_wfsopen((filename.c_str()), mode.c_str(), _SH_DENYNO);
+    #else
+    *fp = ::_fsopen((filename.c_str()), mode.c_str(), _SH_DENYNO);
+    #endif
+    #if defined(SPDLOG_PREVENT_CHILD_FD)
+    if (*fp != nullptr) {
+        auto file_handle = reinterpret_cast<HANDLE>(_get_osfhandle(::_fileno(*fp)));
+        if (!::SetHandleInformation(file_handle, HANDLE_FLAG_INHERIT, 0)) {
+            ::fclose(*fp);
+            *fp = nullptr;
+        }
+    }
+    #endif
+#else  // unix
+    #if defined(SPDLOG_PREVENT_CHILD_FD)
+    const int mode_flag = mode == SPDLOG_FILENAME_T("ab") ? O_APPEND : O_TRUNC;
+    const int fd =
+        ::open((filename.c_str()), O_CREAT | O_WRONLY | O_CLOEXEC | mode_flag, mode_t(0644));
+    if (fd == -1) {
+        return true;
+    }
+    *fp = ::fdopen(fd, mode.c_str());
+    if (*fp == nullptr) {
+        ::close(fd);
+    }
+    #else
+    *fp = ::fopen((filename.c_str()), mode.c_str());
+    #endif
+#endif
+
+    return *fp == nullptr;
+}
+
+SPDLOG_INLINE int remove(const filename_t &filename) SPDLOG_NOEXCEPT {
+#if defined(_WIN32) && defined(SPDLOG_WCHAR_FILENAMES)
+    return ::_wremove(filename.c_str());
+#else
+    return std::remove(filename.c_str());
+#endif
+}
+
+SPDLOG_INLINE int remove_if_exists(const filename_t &filename) SPDLOG_NOEXCEPT {
+    return path_exists(filename) ? remove(filename) : 0;
+}
+
+SPDLOG_INLINE int rename(const filename_t &filename1, const filename_t &filename2) SPDLOG_NOEXCEPT {
+#if defined(_WIN32) && defined(SPDLOG_WCHAR_FILENAMES)
+    return ::_wrename(filename1.c_str(), filename2.c_str());
+#else
+    return std::rename(filename1.c_str(), filename2.c_str());
+#endif
+}
+
+// Return true if path exists (file or directory)
+SPDLOG_INLINE bool path_exists(const filename_t &filename) SPDLOG_NOEXCEPT {
+#ifdef _WIN32
+    struct _stat buffer;
+    #ifdef SPDLOG_WCHAR_FILENAMES
+    return (::_wstat(filename.c_str(), &buffer) == 0);
+    #else
+    return (::_stat(filename.c_str(), &buffer) == 0);
+    #endif
+#else  // common linux/unix all have the stat system call
+    struct stat buffer;
+    return (::stat(filename.c_str(), &buffer) == 0);
+#endif
+}
+
+#ifdef _MSC_VER
+    // avoid warning about unreachable statement at the end of filesize()
+    #pragma warning(push)
+    #pragma warning(disable : 4702)
+#endif
+
+// Return file size according to open FILE* object
+SPDLOG_INLINE size_t filesize(FILE *f) {
+    if (f == nullptr) {
+        throw_spdlog_ex("Failed getting file size. fd is null");
+    }
+#if defined(_WIN32) && !defined(__CYGWIN__)
+    int fd = ::_fileno(f);
+    #if defined(_WIN64)  // 64 bits
+    __int64 ret = ::_filelengthi64(fd);
+    if (ret >= 0) {
+        return static_cast<size_t>(ret);
+    }
+
+    #else  // windows 32 bits
+    long ret = ::_filelength(fd);
+    if (ret >= 0) {
+        return static_cast<size_t>(ret);
+    }
+    #endif
+
+#else  // unix
+    // OpenBSD and AIX doesn't compile with :: before the fileno(..)
+    #if defined(__OpenBSD__) || defined(_AIX)
+    int fd = fileno(f);
+    #else
+    int fd = ::fileno(f);
+    #endif
+    // 64 bits(but not in osx, linux/musl or cygwin, where fstat64 is deprecated)
+    #if ((defined(__linux__) && defined(__GLIBC__)) || defined(__sun) || defined(_AIX)) && \
+        (defined(__LP64__) || defined(_LP64))
+    struct stat64 st;
+    if (::fstat64(fd, &st) == 0) {
+        return static_cast<size_t>(st.st_size);
+    }
+    #else  // other unix or linux 32 bits or cygwin
+    struct stat st;
+    if (::fstat(fd, &st) == 0) {
+        return static_cast<size_t>(st.st_size);
+    }
+    #endif
+#endif
+    throw_spdlog_ex("Failed getting file size from fd", errno);
+    return 0;  // will not be reached.
+}
+
+#ifdef _MSC_VER
+    #pragma warning(pop)
+#endif
+
+// Return utc offset in minutes or throw spdlog_ex on failure
+SPDLOG_INLINE int utc_minutes_offset(const std::tm &tm) {
+#ifdef _WIN32
+    #if _WIN32_WINNT < _WIN32_WINNT_WS08
+    TIME_ZONE_INFORMATION tzinfo;
+    auto rv = ::GetTimeZoneInformation(&tzinfo);
+    #else
+    DYNAMIC_TIME_ZONE_INFORMATION tzinfo;
+    auto rv = ::GetDynamicTimeZoneInformation(&tzinfo);
+    #endif
+    if (rv == TIME_ZONE_ID_INVALID) throw_spdlog_ex("Failed getting timezone info. ", errno);
+
+    int offset = -tzinfo.Bias;
+    if (tm.tm_isdst) {
+        offset -= tzinfo.DaylightBias;
+    } else {
+        offset -= tzinfo.StandardBias;
+    }
+    return offset;
+#else
+
+    #if defined(sun) || defined(__sun) || defined(_AIX) || \
+        (defined(__NEWLIB__) && !defined(__TM_GMTOFF)) ||  \
+        (!defined(_BSD_SOURCE) && !defined(_GNU_SOURCE))
+    // 'tm_gmtoff' field is BSD extension and it's missing on SunOS/Solaris
+    struct helper {
+        static long int calculate_gmt_offset(const std::tm &localtm = details::os::localtime(),
+                                             const std::tm &gmtm = details::os::gmtime()) {
+            int local_year = localtm.tm_year + (1900 - 1);
+            int gmt_year = gmtm.tm_year + (1900 - 1);
+
+            long int days = (
+                // difference in day of year
+                localtm.tm_yday -
+                gmtm.tm_yday
+
+                // + intervening leap days
+                + ((local_year >> 2) - (gmt_year >> 2)) - (local_year / 100 - gmt_year / 100) +
+                ((local_year / 100 >> 2) - (gmt_year / 100 >> 2))
+
+                // + difference in years * 365 */
+                + static_cast<long int>(local_year - gmt_year) * 365);
+
+            long int hours = (24 * days) + (localtm.tm_hour - gmtm.tm_hour);
+            long int mins = (60 * hours) + (localtm.tm_min - gmtm.tm_min);
+            long int secs = (60 * mins) + (localtm.tm_sec - gmtm.tm_sec);
+
+            return secs;
+        }
+    };
+
+    auto offset_seconds = helper::calculate_gmt_offset(tm);
+    #else
+    auto offset_seconds = tm.tm_gmtoff;
+    #endif
+
+    return static_cast<int>(offset_seconds / 60);
+#endif
+}
+
+// Return current thread id as size_t
+// It exists because the std::this_thread::get_id() is much slower(especially
+// under VS 2013)
+SPDLOG_INLINE size_t _thread_id() SPDLOG_NOEXCEPT {
+#ifdef _WIN32
+    return static_cast<size_t>(::GetCurrentThreadId());
+#elif defined(__linux__)
+    #if defined(__ANDROID__) && defined(__ANDROID_API__) && (__ANDROID_API__ < 21)
+        #define SYS_gettid __NR_gettid
+    #endif
+    return static_cast<size_t>(::syscall(SYS_gettid));
+#elif defined(_AIX)
+    struct __pthrdsinfo buf;
+    int reg_size = 0;
+    pthread_t pt = pthread_self();
+    int retval = pthread_getthrds_np(&pt, PTHRDSINFO_QUERY_TID, &buf, sizeof(buf), NULL, &reg_size);
+    int tid = (!retval) ? buf.__pi_tid : 0;
+    return static_cast<size_t>(tid);
+#elif defined(__DragonFly__) || defined(__FreeBSD__)
+    return static_cast<size_t>(::pthread_getthreadid_np());
+#elif defined(__NetBSD__)
+    return static_cast<size_t>(::_lwp_self());
+#elif defined(__OpenBSD__)
+    return static_cast<size_t>(::getthrid());
+#elif defined(__sun)
+    return static_cast<size_t>(::thr_self());
+#elif __APPLE__
+    uint64_t tid;
+    // There is no pthread_threadid_np prior to Mac OS X 10.6, and it is not supported on any PPC,
+    // including 10.6.8 Rosetta. __POWERPC__ is Apple-specific define encompassing ppc and ppc64.
+    #ifdef MAC_OS_X_VERSION_MAX_ALLOWED
+    {
+        #if (MAC_OS_X_VERSION_MAX_ALLOWED < 1060) || defined(__POWERPC__)
+        tid = pthread_mach_thread_np(pthread_self());
+        #elif MAC_OS_X_VERSION_MIN_REQUIRED < 1060
+        if (&pthread_threadid_np) {
+            pthread_threadid_np(nullptr, &tid);
+        } else {
+            tid = pthread_mach_thread_np(pthread_self());
+        }
+        #else
+        pthread_threadid_np(nullptr, &tid);
+        #endif
+    }
+    #else
+    pthread_threadid_np(nullptr, &tid);
+    #endif
+    return static_cast<size_t>(tid);
+#else  // Default to standard C++11 (other Unix)
+    return static_cast<size_t>(std::hash<std::thread::id>()(std::this_thread::get_id()));
+#endif
+}
+
+// Return current thread id as size_t (from thread local storage)
+SPDLOG_INLINE size_t thread_id() SPDLOG_NOEXCEPT {
+#if defined(SPDLOG_NO_TLS)
+    return _thread_id();
+#else  // cache thread id in tls
+    static thread_local const size_t tid = _thread_id();
+    return tid;
+#endif
+}
+
+// This is avoid msvc issue in sleep_for that happens if the clock changes.
+// See https://github.com/gabime/spdlog/issues/609
+SPDLOG_INLINE void sleep_for_millis(unsigned int milliseconds) SPDLOG_NOEXCEPT {
+#if defined(_WIN32)
+    ::Sleep(milliseconds);
+#else
+    std::this_thread::sleep_for(std::chrono::milliseconds(milliseconds));
+#endif
+}
+
+// wchar support for windows file names (SPDLOG_WCHAR_FILENAMES must be defined)
+#if defined(_WIN32) && defined(SPDLOG_WCHAR_FILENAMES)
+SPDLOG_INLINE std::string filename_to_str(const filename_t &filename) {
+    memory_buf_t buf;
+    wstr_to_utf8buf(filename, buf);
+    return SPDLOG_BUF_TO_STRING(buf);
+}
+#else
+SPDLOG_INLINE std::string filename_to_str(const filename_t &filename) { return filename; }
+#endif
+
+SPDLOG_INLINE int pid() SPDLOG_NOEXCEPT {
+#ifdef _WIN32
+    return conditional_static_cast<int>(::GetCurrentProcessId());
+#else
+    return conditional_static_cast<int>(::getpid());
+#endif
+}
+
+// Determine if the terminal supports colors
+// Based on: https://github.com/agauniyal/rang/
+SPDLOG_INLINE bool is_color_terminal() SPDLOG_NOEXCEPT {
+#ifdef _WIN32
+    return true;
+#else
+
+    static const bool result = []() {
+        const char *env_colorterm_p = std::getenv("COLORTERM");
+        if (env_colorterm_p != nullptr) {
+            return true;
+        }
+
+        static constexpr std::array<const char *, 16> terms = {
+            {"ansi", "color", "console", "cygwin", "gnome", "konsole", "kterm", "linux", "msys",
+             "putty", "rxvt", "screen", "vt100", "xterm", "alacritty", "vt102"}};
+
+        const char *env_term_p = std::getenv("TERM");
+        if (env_term_p == nullptr) {
+            return false;
+        }
+
+        return std::any_of(terms.begin(), terms.end(), [&](const char *term) {
+            return std::strstr(env_term_p, term) != nullptr;
+        });
+    }();
+
+    return result;
+#endif
+}
+
+// Determine if the terminal attached
+// Source: https://github.com/agauniyal/rang/
+SPDLOG_INLINE bool in_terminal(FILE *file) SPDLOG_NOEXCEPT {
+#ifdef _WIN32
+    return ::_isatty(_fileno(file)) != 0;
+#else
+    return ::isatty(fileno(file)) != 0;
+#endif
+}
+
+#if (defined(SPDLOG_WCHAR_TO_UTF8_SUPPORT) || defined(SPDLOG_WCHAR_FILENAMES)) && defined(_WIN32)
+SPDLOG_INLINE void wstr_to_utf8buf(wstring_view_t wstr, memory_buf_t &target) {
+    if (wstr.size() > static_cast<size_t>((std::numeric_limits<int>::max)()) / 4 - 1) {
+        throw_spdlog_ex("UTF-16 string is too big to be converted to UTF-8");
+    }
+
+    int wstr_size = static_cast<int>(wstr.size());
+    if (wstr_size == 0) {
+        target.resize(0);
+        return;
+    }
+
+    int result_size = static_cast<int>(target.capacity());
+    if ((wstr_size + 1) * 4 > result_size) {
+        result_size =
+            ::WideCharToMultiByte(CP_UTF8, 0, wstr.data(), wstr_size, NULL, 0, NULL, NULL);
+    }
+
+    if (result_size > 0) {
+        target.resize(result_size);
+        result_size = ::WideCharToMultiByte(CP_UTF8, 0, wstr.data(), wstr_size, target.data(),
+                                            result_size, NULL, NULL);
+
+        if (result_size > 0) {
+            target.resize(result_size);
+            return;
+        }
+    }
+
+    throw_spdlog_ex(
+        fmt_lib::format("WideCharToMultiByte failed. Last error: {}", ::GetLastError()));
+}
+
+SPDLOG_INLINE void utf8_to_wstrbuf(string_view_t str, wmemory_buf_t &target) {
+    if (str.size() > static_cast<size_t>((std::numeric_limits<int>::max)()) - 1) {
+        throw_spdlog_ex("UTF-8 string is too big to be converted to UTF-16");
+    }
+
+    int str_size = static_cast<int>(str.size());
+    if (str_size == 0) {
+        target.resize(0);
+        return;
+    }
+
+    // find the size to allocate for the result buffer
+    int result_size =
+        ::MultiByteToWideChar(CP_UTF8, 0, str.data(), str_size, NULL, 0);
+
+    if (result_size > 0) {
+        target.resize(result_size);
+        result_size = ::MultiByteToWideChar(CP_UTF8, 0, str.data(), str_size, target.data(),
+                                            result_size);
+        if (result_size > 0) {
+            assert(result_size == target.size());
+            return;
+        }
+    }
+
+    throw_spdlog_ex(
+        fmt_lib::format("MultiByteToWideChar failed. Last error: {}", ::GetLastError()));
+}
+#endif  // (defined(SPDLOG_WCHAR_TO_UTF8_SUPPORT) || defined(SPDLOG_WCHAR_FILENAMES)) &&
+        // defined(_WIN32)
+
+// return true on success
+static SPDLOG_INLINE bool mkdir_(const filename_t &path) {
+#ifdef _WIN32
+    #ifdef SPDLOG_WCHAR_FILENAMES
+    return ::_wmkdir(path.c_str()) == 0;
+    #else
+    return ::_mkdir(path.c_str()) == 0;
+    #endif
+#else
+    return ::mkdir(path.c_str(), mode_t(0755)) == 0;
+#endif
+}
+
+// create the given directory - and all directories leading to it
+// return true on success or if the directory already exists
+SPDLOG_INLINE bool create_dir(const filename_t &path) {
+    if (path_exists(path)) {
+        return true;
+    }
+
+    if (path.empty()) {
+        return false;
+    }
+
+    size_t search_offset = 0;
+    do {
+        auto token_pos = path.find_first_of(folder_seps_filename, search_offset);
+        // treat the entire path as a folder if no folder separator not found
+        if (token_pos == filename_t::npos) {
+            token_pos = path.size();
+        }
+
+        auto subdir = path.substr(0, token_pos);
+#ifdef _WIN32
+        // if subdir is just a drive letter, add a slash e.g. "c:"=>"c:\",
+        // otherwise path_exists(subdir) returns false (issue #3079)
+        const bool is_drive = subdir.length() == 2 && subdir[1] == ':';
+        if (is_drive) {
+            subdir += '\\';
+            token_pos++;
+        }
+#endif
+
+        if (!subdir.empty() && !path_exists(subdir) && !mkdir_(subdir)) {
+            return false;  // return error if failed creating dir
+        }
+        search_offset = token_pos + 1;
+    } while (search_offset < path.size());
+
+    return true;
+}
+
+// Return directory name from given path or empty string
+// "abc/file" => "abc"
+// "abc/" => "abc"
+// "abc" => ""
+// "abc///" => "abc//"
+SPDLOG_INLINE filename_t dir_name(const filename_t &path) {
+    auto pos = path.find_last_of(folder_seps_filename);
+    return pos != filename_t::npos ? path.substr(0, pos) : filename_t{};
+}
+
+std::string SPDLOG_INLINE getenv(const char *field) {
+#if defined(_MSC_VER)
+    #if defined(__cplusplus_winrt)
+    return std::string{};  // not supported under uwp
+    #else
+    size_t len = 0;
+    char buf[128];
+    bool ok = ::getenv_s(&len, buf, sizeof(buf), field) == 0;
+    return ok ? buf : std::string{};
+    #endif
+#else  // revert to getenv
+    char *buf = ::getenv(field);
+    return buf ? buf : std::string{};
+#endif
+}
+
+// Do fsync by FILE handlerpointer
+// Return true on success
+SPDLOG_INLINE bool fsync(FILE *fp) {
+#ifdef _WIN32
+    return FlushFileBuffers(reinterpret_cast<HANDLE>(_get_osfhandle(_fileno(fp)))) != 0;
+#else
+    return ::fsync(fileno(fp)) == 0;
+#endif
+}
+
+// Do non-locking fwrite if possible by the os or use the regular locking fwrite
+// Return true on success.
+SPDLOG_INLINE bool fwrite_bytes(const void *ptr, const size_t n_bytes, FILE *fp) {
+    #if defined(_WIN32) && defined(SPDLOG_FWRITE_UNLOCKED)
+    return _fwrite_nolock(ptr, 1, n_bytes, fp) == n_bytes;
+    #elif defined(SPDLOG_FWRITE_UNLOCKED)
+    return ::fwrite_unlocked(ptr, 1, n_bytes, fp) == n_bytes;
+    #else
+    return std::fwrite(ptr, 1, n_bytes, fp) == n_bytes;
+    #endif
+}
+
+}  // namespace os
+}  // namespace details
+}  // namespace spdlog

spdlog/details/os.h

@@ -0,0 +1,127 @@
+// Copyright(c) 2015-present, Gabi Melman & spdlog contributors.
+// Distributed under the MIT License (http://opensource.org/licenses/MIT)
+
+#pragma once
+
+#include <ctime>  // std::time_t
+#include <spdlog/common.h>
+
+namespace spdlog {
+namespace details {
+namespace os {
+
+SPDLOG_API spdlog::log_clock::time_point now() SPDLOG_NOEXCEPT;
+
+SPDLOG_API std::tm localtime(const std::time_t &time_tt) SPDLOG_NOEXCEPT;
+
+SPDLOG_API std::tm localtime() SPDLOG_NOEXCEPT;
+
+SPDLOG_API std::tm gmtime(const std::time_t &time_tt) SPDLOG_NOEXCEPT;
+
+SPDLOG_API std::tm gmtime() SPDLOG_NOEXCEPT;
+
+// eol definition
+#if !defined(SPDLOG_EOL)
+    #ifdef _WIN32
+        #define SPDLOG_EOL "\r\n"
+    #else
+        #define SPDLOG_EOL "\n"
+    #endif
+#endif
+
+SPDLOG_CONSTEXPR static const char *default_eol = SPDLOG_EOL;
+
+// folder separator
+#if !defined(SPDLOG_FOLDER_SEPS)
+    #ifdef _WIN32
+        #define SPDLOG_FOLDER_SEPS "\\/"
+    #else
+        #define SPDLOG_FOLDER_SEPS "/"
+    #endif
+#endif
+
+SPDLOG_CONSTEXPR static const char folder_seps[] = SPDLOG_FOLDER_SEPS;
+SPDLOG_CONSTEXPR static const filename_t::value_type folder_seps_filename[] =
+    SPDLOG_FILENAME_T(SPDLOG_FOLDER_SEPS);
+
+// fopen_s on non windows for writing
+SPDLOG_API bool fopen_s(FILE **fp, const filename_t &filename, const filename_t &mode);
+
+// Remove filename. return 0 on success
+SPDLOG_API int remove(const filename_t &filename) SPDLOG_NOEXCEPT;
+
+// Remove file if exists. return 0 on success
+// Note: Non atomic (might return failure to delete if concurrently deleted by other process/thread)
+SPDLOG_API int remove_if_exists(const filename_t &filename) SPDLOG_NOEXCEPT;
+
+SPDLOG_API int rename(const filename_t &filename1, const filename_t &filename2) SPDLOG_NOEXCEPT;
+
+// Return if file exists.
+SPDLOG_API bool path_exists(const filename_t &filename) SPDLOG_NOEXCEPT;
+
+// Return file size according to open FILE* object
+SPDLOG_API size_t filesize(FILE *f);
+
+// Return utc offset in minutes or throw spdlog_ex on failure
+SPDLOG_API int utc_minutes_offset(const std::tm &tm = details::os::localtime());
+
+// Return current thread id as size_t
+// It exists because the std::this_thread::get_id() is much slower(especially
+// under VS 2013)
+SPDLOG_API size_t _thread_id() SPDLOG_NOEXCEPT;
+
+// Return current thread id as size_t (from thread local storage)
+SPDLOG_API size_t thread_id() SPDLOG_NOEXCEPT;
+
+// This is avoid msvc issue in sleep_for that happens if the clock changes.
+// See https://github.com/gabime/spdlog/issues/609
+SPDLOG_API void sleep_for_millis(unsigned int milliseconds) SPDLOG_NOEXCEPT;
+
+SPDLOG_API std::string filename_to_str(const filename_t &filename);
+
+SPDLOG_API int pid() SPDLOG_NOEXCEPT;
+
+// Determine if the terminal supports colors
+// Source: https://github.com/agauniyal/rang/
+SPDLOG_API bool is_color_terminal() SPDLOG_NOEXCEPT;
+
+// Determine if the terminal attached
+// Source: https://github.com/agauniyal/rang/
+SPDLOG_API bool in_terminal(FILE *file) SPDLOG_NOEXCEPT;
+
+#if (defined(SPDLOG_WCHAR_TO_UTF8_SUPPORT) || defined(SPDLOG_WCHAR_FILENAMES)) && defined(_WIN32)
+SPDLOG_API void wstr_to_utf8buf(wstring_view_t wstr, memory_buf_t &target);
+
+SPDLOG_API void utf8_to_wstrbuf(string_view_t str, wmemory_buf_t &target);
+#endif
+
+// Return directory name from given path or empty string
+// "abc/file" => "abc"
+// "abc/" => "abc"
+// "abc" => ""
+// "abc///" => "abc//"
+SPDLOG_API filename_t dir_name(const filename_t &path);
+
+// Create a dir from the given path.
+// Return true if succeeded or if this dir already exists.
+SPDLOG_API bool create_dir(const filename_t &path);
+
+// non thread safe, cross platform getenv/getenv_s
+// return empty string if field not found
+SPDLOG_API std::string getenv(const char *field);
+
+// Do fsync by FILE objectpointer.
+// Return true on success.
+SPDLOG_API bool fsync(FILE *fp);
+
+// Do non-locking fwrite if possible by the os or use the regular locking fwrite
+// Return true on success.
+SPDLOG_API bool fwrite_bytes(const void *ptr, const size_t n_bytes, FILE *fp);
+
+}  // namespace os
+}  // namespace details
+}  // namespace spdlog
+
+#ifdef SPDLOG_HEADER_ONLY
+    #include "os-inl.h"
+#endif

spdlog/details/periodic_worker-inl.h

@@ -0,0 +1,26 @@
+// Copyright(c) 2015-present, Gabi Melman & spdlog contributors.
+// Distributed under the MIT License (http://opensource.org/licenses/MIT)
+
+#pragma once
+
+#ifndef SPDLOG_HEADER_ONLY
+    #include <spdlog/details/periodic_worker.h>
+#endif
+
+namespace spdlog {
+namespace details {
+
+// stop the worker thread and join it
+SPDLOG_INLINE periodic_worker::~periodic_worker() {
+    if (worker_thread_.joinable()) {
+        {
+            std::lock_guard<std::mutex> lock(mutex_);
+            active_ = false;
+        }
+        cv_.notify_one();
+        worker_thread_.join();
+    }
+}
+
+}  // namespace details
+}  // namespace spdlog

spdlog/details/periodic_worker.h

@@ -0,0 +1,58 @@
+// Copyright(c) 2015-present, Gabi Melman & spdlog contributors.
+// Distributed under the MIT License (http://opensource.org/licenses/MIT)
+
+#pragma once
+
+// periodic worker thread - periodically executes the given callback function.
+//
+// RAII over the owned thread:
+//    creates the thread on construction.
+//    stops and joins the thread on destruction (if the thread is executing a callback, wait for it
+//    to finish first).
+
+#include <chrono>
+#include <condition_variable>
+#include <functional>
+#include <mutex>
+#include <thread>
+namespace spdlog {
+namespace details {
+
+class SPDLOG_API periodic_worker {
+public:
+    template <typename Rep, typename Period>
+    periodic_worker(const std::function<void()> &callback_fun,
+                    std::chrono::duration<Rep, Period> interval) {
+        active_ = (interval > std::chrono::duration<Rep, Period>::zero());
+        if (!active_) {
+            return;
+        }
+
+        worker_thread_ = std::thread([this, callback_fun, interval]() {
+            for (;;) {
+                std::unique_lock<std::mutex> lock(this->mutex_);
+                if (this->cv_.wait_for(lock, interval, [this] { return !this->active_; })) {
+                    return;  // active_ == false, so exit this thread
+                }
+                callback_fun();
+            }
+        });
+    }
+    std::thread &get_thread() { return worker_thread_; }
+    periodic_worker(const periodic_worker &) = delete;
+    periodic_worker &operator=(const periodic_worker &) = delete;
+    // stop the worker thread and join it
+    ~periodic_worker();
+
+private:
+    bool active_;
+    std::thread worker_thread_;
+    std::mutex mutex_;
+    std::condition_variable cv_;
+};
+}  // namespace details
+}  // namespace spdlog
+
+#ifdef SPDLOG_HEADER_ONLY
+    #include "periodic_worker-inl.h"
+#endif

spdlog/details/registry-inl.h

@@ -0,0 +1,261 @@
+// Copyright(c) 2015-present, Gabi Melman & spdlog contributors.
+// Distributed under the MIT License (http://opensource.org/licenses/MIT)
+
+#pragma once
+
+#ifndef SPDLOG_HEADER_ONLY
+    #include <spdlog/details/registry.h>
+#endif
+
+#include <spdlog/common.h>
+#include <spdlog/details/periodic_worker.h>
+#include <spdlog/logger.h>
+#include <spdlog/pattern_formatter.h>
+
+#ifndef SPDLOG_DISABLE_DEFAULT_LOGGER
+    // support for the default stdout color logger
+    #ifdef _WIN32
+        #include <spdlog/sinks/wincolor_sink.h>
+    #else
+        #include <spdlog/sinks/ansicolor_sink.h>
+    #endif
+#endif  // SPDLOG_DISABLE_DEFAULT_LOGGER
+
+#include <chrono>
+#include <functional>
+#include <memory>
+#include <string>
+#include <unordered_map>
+
+namespace spdlog {
+namespace details {
+
+SPDLOG_INLINE registry::registry()
+    : formatter_(new pattern_formatter()) {
+#ifndef SPDLOG_DISABLE_DEFAULT_LOGGER
+    // create default logger (ansicolor_stdout_sink_mt or wincolor_stdout_sink_mt in windows).
+    #ifdef _WIN32
+    auto color_sink = std::make_shared<sinks::wincolor_stdout_sink_mt>();
+    #else
+    auto color_sink = std::make_shared<sinks::ansicolor_stdout_sink_mt>();
+    #endif
+
+    const char *default_logger_name = "";
+    default_logger_ = std::make_shared<spdlog::logger>(default_logger_name, std::move(color_sink));
+    loggers_[default_logger_name] = default_logger_;
+
+#endif  // SPDLOG_DISABLE_DEFAULT_LOGGER
+}
+
+SPDLOG_INLINE registry::~registry() = default;
+
+SPDLOG_INLINE void registry::register_logger(std::shared_ptr<logger> new_logger) {
+    std::lock_guard<std::mutex> lock(logger_map_mutex_);
+    register_logger_(std::move(new_logger));
+}
+
+SPDLOG_INLINE void registry::initialize_logger(std::shared_ptr<logger> new_logger) {
+    std::lock_guard<std::mutex> lock(logger_map_mutex_);
+    new_logger->set_formatter(formatter_->clone());
+
+    if (err_handler_) {
+        new_logger->set_error_handler(err_handler_);
+    }
+
+    // set new level according to previously configured level or default level
+    auto it = log_levels_.find(new_logger->name());
+    auto new_level = it != log_levels_.end() ? it->second : global_log_level_;
+    new_logger->set_level(new_level);
+
+    new_logger->flush_on(flush_level_);
+
+    if (backtrace_n_messages_ > 0) {
+        new_logger->enable_backtrace(backtrace_n_messages_);
+    }
+
+    if (automatic_registration_) {
+        register_logger_(std::move(new_logger));
+    }
+}
+
+SPDLOG_INLINE std::shared_ptr<logger> registry::get(const std::string &logger_name) {
+    std::lock_guard<std::mutex> lock(logger_map_mutex_);
+    auto found = loggers_.find(logger_name);
+    return found == loggers_.end() ? nullptr : found->second;
+}
+
+SPDLOG_INLINE std::shared_ptr<logger> registry::default_logger() {
+    std::lock_guard<std::mutex> lock(logger_map_mutex_);
+    return default_logger_;
+}
+
+// Return raw ptr to the default logger.
+// To be used directly by the spdlog default api (e.g. spdlog::info)
+// This make the default API faster, but cannot be used concurrently with set_default_logger().
+// e.g do not call set_default_logger() from one thread while calling spdlog::info() from another.
+SPDLOG_INLINE logger *registry::get_default_raw() { return default_logger_.get(); }
+
+// set default logger.
+// default logger is stored in default_logger_ (for faster retrieval) and in the loggers_ map.
+SPDLOG_INLINE void registry::set_default_logger(std::shared_ptr<logger> new_default_logger) {
+    std::lock_guard<std::mutex> lock(logger_map_mutex_);
+    if (new_default_logger != nullptr) {
+        loggers_[new_default_logger->name()] = new_default_logger;
+    }
+    default_logger_ = std::move(new_default_logger);
+}
+
+SPDLOG_INLINE void registry::set_tp(std::shared_ptr<thread_pool> tp) {
+    std::lock_guard<std::recursive_mutex> lock(tp_mutex_);
+    tp_ = std::move(tp);
+}
+
+SPDLOG_INLINE std::shared_ptr<thread_pool> registry::get_tp() {
+    std::lock_guard<std::recursive_mutex> lock(tp_mutex_);
+    return tp_;
+}
+
+// Set global formatter. Each sink in each logger will get a clone of this object
+SPDLOG_INLINE void registry::set_formatter(std::unique_ptr<formatter> formatter) {
+    std::lock_guard<std::mutex> lock(logger_map_mutex_);
+    formatter_ = std::move(formatter);
+    for (auto &l : loggers_) {
+        l.second->set_formatter(formatter_->clone());
+    }
+}
+
+SPDLOG_INLINE void registry::enable_backtrace(size_t n_messages) {
+    std::lock_guard<std::mutex> lock(logger_map_mutex_);
+    backtrace_n_messages_ = n_messages;
+
+    for (auto &l : loggers_) {
+        l.second->enable_backtrace(n_messages);
+    }
+}
+
+SPDLOG_INLINE void registry::disable_backtrace() {
+    std::lock_guard<std::mutex> lock(logger_map_mutex_);
+    backtrace_n_messages_ = 0;
+    for (auto &l : loggers_) {
+        l.second->disable_backtrace();
+    }
+}
+
+SPDLOG_INLINE void registry::set_level(level::level_enum log_level) {
+    std::lock_guard<std::mutex> lock(logger_map_mutex_);
+    for (auto &l : loggers_) {
+        l.second->set_level(log_level);
+    }
+    global_log_level_ = log_level;
+}
+
+SPDLOG_INLINE void registry::flush_on(level::level_enum log_level) {
+    std::lock_guard<std::mutex> lock(logger_map_mutex_);
+    for (auto &l : loggers_) {
+        l.second->flush_on(log_level);
+    }
+    flush_level_ = log_level;
+}
+
+SPDLOG_INLINE void registry::set_error_handler(err_handler handler) {
+    std::lock_guard<std::mutex> lock(logger_map_mutex_);
+    for (auto &l : loggers_) {
+        l.second->set_error_handler(handler);
+    }
+    err_handler_ = std::move(handler);
+}
+
+SPDLOG_INLINE void registry::apply_all(
+    const std::function<void(const std::shared_ptr<logger>)> &fun) {
+    std::lock_guard<std::mutex> lock(logger_map_mutex_);
+    for (auto &l : loggers_) {
+        fun(l.second);
+    }
+}
+
+SPDLOG_INLINE void registry::flush_all() {
+    std::lock_guard<std::mutex> lock(logger_map_mutex_);
+    for (auto &l : loggers_) {
+        l.second->flush();
+    }
+}
+
+SPDLOG_INLINE void registry::drop(const std::string &logger_name) {
+    std::lock_guard<std::mutex> lock(logger_map_mutex_);
+    auto is_default_logger = default_logger_ && default_logger_->name() == logger_name;
+    loggers_.erase(logger_name);
+    if (is_default_logger) {
+        default_logger_.reset();
+    }
+}
+
+SPDLOG_INLINE void registry::drop_all() {
+    std::lock_guard<std::mutex> lock(logger_map_mutex_);
+    loggers_.clear();
+    default_logger_.reset();
+}
+
+// clean all resources and threads started by the registry
+SPDLOG_INLINE void registry::shutdown() {
+    {
+        std::lock_guard<std::mutex> lock(flusher_mutex_);
+        periodic_flusher_.reset();
+    }
+
+    drop_all();
+
+    {
+        std::lock_guard<std::recursive_mutex> lock(tp_mutex_);
+        tp_.reset();
+    }
+}
+
+SPDLOG_INLINE std::recursive_mutex &registry::tp_mutex() { return tp_mutex_; }
+
+SPDLOG_INLINE void registry::set_automatic_registration(bool automatic_registration) {
+    std::lock_guard<std::mutex> lock(logger_map_mutex_);
+    automatic_registration_ = automatic_registration;
+}
+
+SPDLOG_INLINE void registry::set_levels(log_levels levels, level::level_enum *global_level) {
+    std::lock_guard<std::mutex> lock(logger_map_mutex_);
+    log_levels_ = std::move(levels);
+    auto global_level_requested = global_level != nullptr;
+    global_log_level_ = global_level_requested ? *global_level : global_log_level_;
+
+    for (auto &logger : loggers_) {
+        auto logger_entry = log_levels_.find(logger.first);
+        if (logger_entry != log_levels_.end()) {
+            logger.second->set_level(logger_entry->second);
+        } else if (global_level_requested) {
+            logger.second->set_level(*global_level);
+        }
+    }
+}
+
+SPDLOG_INLINE registry &registry::instance() {
+    static registry s_instance;
+    return s_instance;
+}
+
+SPDLOG_INLINE void registry::apply_logger_env_levels(std::shared_ptr<logger> new_logger) {
+    std::lock_guard<std::mutex> lock(logger_map_mutex_);
+    auto it = log_levels_.find(new_logger->name());
+    auto new_level = it != log_levels_.end() ? it->second : global_log_level_;
+    new_logger->set_level(new_level);
+}
+
+SPDLOG_INLINE void registry::throw_if_exists_(const std::string &logger_name) {
+    if (loggers_.find(logger_name) != loggers_.end()) {
+        throw_spdlog_ex("logger with name '" + logger_name + "' already exists");
+    }
+}
+
+SPDLOG_INLINE void registry::register_logger_(std::shared_ptr<logger> new_logger) {
+    auto logger_name = new_logger->name();
+    throw_if_exists_(logger_name);
+    loggers_[logger_name] = std::move(new_logger);
+}
+
+}  // namespace details
+}  // namespace spdlog

spdlog/details/registry.h

@@ -0,0 +1,129 @@
+// Copyright(c) 2015-present, Gabi Melman & spdlog contributors.
+// Distributed under the MIT License (http://opensource.org/licenses/MIT)
+
+#pragma once
+
+// Loggers registry of unique name->logger pointer
+// An attempt to create a logger with an already existing name will result with spdlog_ex exception.
+// If user requests a non existing logger, nullptr will be returned
+// This class is thread safe
+
+#include <spdlog/common.h>
+#include <spdlog/details/periodic_worker.h>
+
+#include <chrono>
+#include <functional>
+#include <memory>
+#include <mutex>
+#include <string>
+#include <unordered_map>
+
+namespace spdlog {
+class logger;
+
+namespace details {
+class thread_pool;
+
+class SPDLOG_API registry {
+public:
+    using log_levels = std::unordered_map<std::string, level::level_enum>;
+    registry(const registry &) = delete;
+    registry &operator=(const registry &) = delete;
+
+    void register_logger(std::shared_ptr<logger> new_logger);
+    void initialize_logger(std::shared_ptr<logger> new_logger);
+    std::shared_ptr<logger> get(const std::string &logger_name);
+    std::shared_ptr<logger> default_logger();
+
+    // Return raw ptr to the default logger.
+    // To be used directly by the spdlog default api (e.g. spdlog::info)
+    // This make the default API faster, but cannot be used concurrently with set_default_logger().
+    // e.g do not call set_default_logger() from one thread while calling spdlog::info() from
+    // another.
+    logger *get_default_raw();
+
+    // set default logger and add it to the registry if not registered already.
+    // default logger is stored in default_logger_ (for faster retrieval) and in the loggers_ map.
+    // Note: Make sure to unregister it when no longer needed or before calling again with a new
+    // logger.
+    void set_default_logger(std::shared_ptr<logger> new_default_logger);
+
+    void set_tp(std::shared_ptr<thread_pool> tp);
+
+    std::shared_ptr<thread_pool> get_tp();
+
+    // Set global formatter. Each sink in each logger will get a clone of this object
+    void set_formatter(std::unique_ptr<formatter> formatter);
+
+    void enable_backtrace(size_t n_messages);
+
+    void disable_backtrace();
+
+    void set_level(level::level_enum log_level);
+
+    void flush_on(level::level_enum log_level);
+
+    template <typename Rep, typename Period>
+    void flush_every(std::chrono::duration<Rep, Period> interval) {
+        std::lock_guard<std::mutex> lock(flusher_mutex_);
+        auto clbk = [this]() { this->flush_all(); };
+        periodic_flusher_ = details::make_unique<periodic_worker>(clbk, interval);
+    }
+
+    std::unique_ptr<periodic_worker> &get_flusher() {
+        std::lock_guard<std::mutex> lock(flusher_mutex_);
+        return periodic_flusher_;
+    }
+
+    void set_error_handler(err_handler handler);
+
+    void apply_all(const std::function<void(const std::shared_ptr<logger>)> &fun);
+
+    void flush_all();
+
+    void drop(const std::string &logger_name);
+
+    void drop_all();
+
+    // clean all resources and threads started by the registry
+    void shutdown();
+
+    std::recursive_mutex &tp_mutex();
+
+    void set_automatic_registration(bool automatic_registration);
+
+    // set levels for all existing/future loggers. global_level can be null if should not set.
+    void set_levels(log_levels levels, level::level_enum *global_level);
+
+    static registry &instance();
+
+    void apply_logger_env_levels(std::shared_ptr<logger> new_logger);
+
+private:
+    registry();
+    ~registry();
+
+    void throw_if_exists_(const std::string &logger_name);
+    void register_logger_(std::shared_ptr<logger> new_logger);
+    bool set_level_from_cfg_(logger *logger);
+    std::mutex logger_map_mutex_, flusher_mutex_;
+    std::recursive_mutex tp_mutex_;
+    std::unordered_map<std::string, std::shared_ptr<logger>> loggers_;
+    log_levels log_levels_;
+    std::unique_ptr<formatter> formatter_;
+    spdlog::level::level_enum global_log_level_ = level::info;
+    level::level_enum flush_level_ = level::off;
+    err_handler err_handler_;
+    std::shared_ptr<thread_pool> tp_;
+    std::unique_ptr<periodic_worker> periodic_flusher_;
+    std::shared_ptr<logger> default_logger_;
+    bool automatic_registration_ = true;
+    size_t backtrace_n_messages_ = 0;
+};
+
+}  // namespace details
+}  // namespace spdlog
+
+#ifdef SPDLOG_HEADER_ONLY
+    #include "registry-inl.h"
+#endif

spdlog/details/synchronous_factory.h

@@ -0,0 +1,22 @@
+// Copyright(c) 2015-present, Gabi Melman & spdlog contributors.
+// Distributed under the MIT License (http://opensource.org/licenses/MIT)
+
+#pragma once
+
+#include "registry.h"
+
+namespace spdlog {
+
+// Default logger factory-  creates synchronous loggers
+class logger;
+
+struct synchronous_factory {
+    template <typename Sink, typename... SinkArgs>
+    static std::shared_ptr<spdlog::logger> create(std::string logger_name, SinkArgs &&...args) {
+        auto sink = std::make_shared<Sink>(std::forward<SinkArgs>(args)...);
+        auto new_logger = std::make_shared<spdlog::logger>(std::move(logger_name), std::move(sink));
+        details::registry::instance().initialize_logger(new_logger);
+        return new_logger;
+    }
+};
+}  // namespace spdlog

spdlog/details/tcp_client-windows.h

@@ -0,0 +1,135 @@
+// Copyright(c) 2015-present, Gabi Melman & spdlog contributors.
+// Distributed under the MIT License (http://opensource.org/licenses/MIT)
+
+#pragma once
+
+#define WIN32_LEAN_AND_MEAN
+// tcp client helper
+#include <spdlog/common.h>
+#include <spdlog/details/os.h>
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string>
+#include <windows.h>
+#include <winsock2.h>
+#include <ws2tcpip.h>
+
+#pragma comment(lib, "Ws2_32.lib")
+#pragma comment(lib, "Mswsock.lib")
+#pragma comment(lib, "AdvApi32.lib")
+
+namespace spdlog {
+namespace details {
+class tcp_client {
+    SOCKET socket_ = INVALID_SOCKET;
+
+    static void init_winsock_() {
+        WSADATA wsaData;
+        auto rv = WSAStartup(MAKEWORD(2, 2), &wsaData);
+        if (rv != 0) {
+            throw_winsock_error_("WSAStartup failed", ::WSAGetLastError());
+        }
+    }
+
+    static void throw_winsock_error_(const std::string &msg, int last_error) {
+        char buf[512];
+        ::FormatMessageA(FORMAT_MESSAGE_FROM_SYSTEM | FORMAT_MESSAGE_IGNORE_INSERTS, NULL,
+                         last_error, MAKELANGID(LANG_NEUTRAL, SUBLANG_DEFAULT), buf,
+                         (sizeof(buf) / sizeof(char)), NULL);
+
+        throw_spdlog_ex(fmt_lib::format("tcp_sink - {}: {}", msg, buf));
+    }
+
+public:
+    tcp_client() { init_winsock_(); }
+
+    ~tcp_client() {
+        close();
+        ::WSACleanup();
+    }
+
+    bool is_connected() const { return socket_ != INVALID_SOCKET; }
+
+    void close() {
+        ::closesocket(socket_);
+        socket_ = INVALID_SOCKET;
+    }
+
+    SOCKET fd() const { return socket_; }
+
+    // try to connect or throw on failure
+    void connect(const std::string &host, int port) {
+        if (is_connected()) {
+            close();
+        }
+        struct addrinfo hints {};
+        ZeroMemory(&hints, sizeof(hints));
+
+        hints.ai_family = AF_UNSPEC;      // To work with IPv4, IPv6, and so on
+        hints.ai_socktype = SOCK_STREAM;  // TCP
+        hints.ai_flags = AI_NUMERICSERV;  // port passed as as numeric value
+        hints.ai_protocol = 0;
+
+        auto port_str = std::to_string(port);
+        struct addrinfo *addrinfo_result;
+        auto rv = ::getaddrinfo(host.c_str(), port_str.c_str(), &hints, &addrinfo_result);
+        int last_error = 0;
+        if (rv != 0) {
+            last_error = ::WSAGetLastError();
+            WSACleanup();
+            throw_winsock_error_("getaddrinfo failed", last_error);
+        }
+
+        // Try each address until we successfully connect(2).
+
+        for (auto *rp = addrinfo_result; rp != nullptr; rp = rp->ai_next) {
+            socket_ = socket(rp->ai_family, rp->ai_socktype, rp->ai_protocol);
+            if (socket_ == INVALID_SOCKET) {
+                last_error = ::WSAGetLastError();
+                WSACleanup();
+                continue;
+            }
+            if (::connect(socket_, rp->ai_addr, (int)rp->ai_addrlen) == 0) {
+                break;
+            } else {
+                last_error = ::WSAGetLastError();
+                close();
+            }
+        }
+        ::freeaddrinfo(addrinfo_result);
+        if (socket_ == INVALID_SOCKET) {
+            WSACleanup();
+            throw_winsock_error_("connect failed", last_error);
+        }
+
+        // set TCP_NODELAY
+        int enable_flag = 1;
+        ::setsockopt(socket_, IPPROTO_TCP, TCP_NODELAY, reinterpret_cast<char *>(&enable_flag),
+                     sizeof(enable_flag));
+    }
+
+    // Send exactly n_bytes of the given data.
+    // On error close the connection and throw.
+    void send(const char *data, size_t n_bytes) {
+        size_t bytes_sent = 0;
+        while (bytes_sent < n_bytes) {
+            const int send_flags = 0;
+            auto write_result =
+                ::send(socket_, data + bytes_sent, (int)(n_bytes - bytes_sent), send_flags);
+            if (write_result == SOCKET_ERROR) {
+                int last_error = ::WSAGetLastError();
+                close();
+                throw_winsock_error_("send failed", last_error);
+            }
+
+            if (write_result == 0)  // (probably should not happen but in any case..)
+            {
+                break;
+            }
+            bytes_sent += static_cast<size_t>(write_result);
+        }
+    }
+};
+}  // namespace details
+}  // namespace spdlog

spdlog/details/tcp_client.h

@@ -0,0 +1,127 @@
+// Copyright(c) 2015-present, Gabi Melman & spdlog contributors.
+// Distributed under the MIT License (http://opensource.org/licenses/MIT)
+
+#pragma once
+
+#ifdef _WIN32
+    #error include tcp_client-windows.h instead
+#endif
+
+// tcp client helper
+#include <spdlog/common.h>
+#include <spdlog/details/os.h>
+
+#include <arpa/inet.h>
+#include <netdb.h>
+#include <netinet/in.h>
+#include <netinet/tcp.h>
+#include <sys/socket.h>
+#include <unistd.h>
+
+#include <string>
+
+namespace spdlog {
+namespace details {
+class tcp_client {
+    int socket_ = -1;
+
+public:
+    bool is_connected() const { return socket_ != -1; }
+
+    void close() {
+        if (is_connected()) {
+            ::close(socket_);
+            socket_ = -1;
+        }
+    }
+
+    int fd() const { return socket_; }
+
+    ~tcp_client() { close(); }
+
+    // try to connect or throw on failure
+    void connect(const std::string &host, int port) {
+        close();
+        struct addrinfo hints {};
+        memset(&hints, 0, sizeof(struct addrinfo));
+        hints.ai_family = AF_UNSPEC;      // To work with IPv4, IPv6, and so on
+        hints.ai_socktype = SOCK_STREAM;  // TCP
+        hints.ai_flags = AI_NUMERICSERV;  // port passed as as numeric value
+        hints.ai_protocol = 0;
+
+        auto port_str = std::to_string(port);
+        struct addrinfo *addrinfo_result;
+        auto rv = ::getaddrinfo(host.c_str(), port_str.c_str(), &hints, &addrinfo_result);
+        if (rv != 0) {
+            throw_spdlog_ex(fmt_lib::format("::getaddrinfo failed: {}", gai_strerror(rv)));
+        }
+
+        // Try each address until we successfully connect(2).
+        int last_errno = 0;
+        for (auto *rp = addrinfo_result; rp != nullptr; rp = rp->ai_next) {
+#if defined(SOCK_CLOEXEC)
+            const int flags = SOCK_CLOEXEC;
+#else
+            const int flags = 0;
+#endif
+            socket_ = ::socket(rp->ai_family, rp->ai_socktype | flags, rp->ai_protocol);
+            if (socket_ == -1) {
+                last_errno = errno;
+                continue;
+            }
+            rv = ::connect(socket_, rp->ai_addr, rp->ai_addrlen);
+            if (rv == 0) {
+                break;
+            }
+            last_errno = errno;
+            ::close(socket_);
+            socket_ = -1;
+        }
+        ::freeaddrinfo(addrinfo_result);
+        if (socket_ == -1) {
+            throw_spdlog_ex("::connect failed", last_errno);
+        }
+
+        // set TCP_NODELAY
+        int enable_flag = 1;
+        ::setsockopt(socket_, IPPROTO_TCP, TCP_NODELAY, reinterpret_cast<char *>(&enable_flag),
+                     sizeof(enable_flag));
+
+        // prevent sigpipe on systems where MSG_NOSIGNAL is not available
+#if defined(SO_NOSIGPIPE) && !defined(MSG_NOSIGNAL)
+        ::setsockopt(socket_, SOL_SOCKET, SO_NOSIGPIPE, reinterpret_cast<char *>(&enable_flag),
+                     sizeof(enable_flag));
+#endif
+
+#if !defined(SO_NOSIGPIPE) && !defined(MSG_NOSIGNAL)
+    #error "tcp_sink would raise SIGPIPE since neither SO_NOSIGPIPE nor MSG_NOSIGNAL are available"
+#endif
+    }
+
+    // Send exactly n_bytes of the given data.
+    // On error close the connection and throw.
+    void send(const char *data, size_t n_bytes) {
+        size_t bytes_sent = 0;
+        while (bytes_sent < n_bytes) {
+#if defined(MSG_NOSIGNAL)
+            const int send_flags = MSG_NOSIGNAL;
+#else
+            const int send_flags = 0;
+#endif
+            auto write_result =
+                ::send(socket_, data + bytes_sent, n_bytes - bytes_sent, send_flags);
+            if (write_result < 0) {
+                close();
+                throw_spdlog_ex("write(2) failed", errno);
+            }
+
+            if (write_result == 0)  // (probably should not happen but in any case..)
+            {
+                break;
+            }
+            bytes_sent += static_cast<size_t>(write_result);
+        }
+    }
+};
+}  // namespace details
+}  // namespace spdlog

spdlog/details/thread_pool-inl.h

@@ -0,0 +1,127 @@
+// Copyright(c) 2015-present, Gabi Melman & spdlog contributors.
+// Distributed under the MIT License (http://opensource.org/licenses/MIT)
+
+#pragma once
+
+#ifndef SPDLOG_HEADER_ONLY
+    #include <spdlog/details/thread_pool.h>
+#endif
+
+#include <cassert>
+#include <spdlog/common.h>
+
+namespace spdlog {
+namespace details {
+
+SPDLOG_INLINE thread_pool::thread_pool(size_t q_max_items,
+                                       size_t threads_n,
+                                       std::function<void()> on_thread_start,
+                                       std::function<void()> on_thread_stop)
+    : q_(q_max_items) {
+    if (threads_n == 0 || threads_n > 1000) {
+        throw_spdlog_ex(
+            "spdlog::thread_pool(): invalid threads_n param (valid "
+            "range is 1-1000)");
+    }
+    for (size_t i = 0; i < threads_n; i++) {
+        threads_.emplace_back([this, on_thread_start, on_thread_stop] {
+            on_thread_start();
+            this->thread_pool::worker_loop_();
+            on_thread_stop();
+        });
+    }
+}
+
+SPDLOG_INLINE thread_pool::thread_pool(size_t q_max_items,
+                                       size_t threads_n,
+                                       std::function<void()> on_thread_start)
+    : thread_pool(q_max_items, threads_n, on_thread_start, [] {}) {}
+
+SPDLOG_INLINE thread_pool::thread_pool(size_t q_max_items, size_t threads_n)
+    : thread_pool(
+          q_max_items, threads_n, [] {}, [] {}) {}
+
+// message all threads to terminate gracefully join them
+SPDLOG_INLINE thread_pool::~thread_pool() {
+    SPDLOG_TRY {
+        for (size_t i = 0; i < threads_.size(); i++) {
+            post_async_msg_(async_msg(async_msg_type::terminate), async_overflow_policy::block);
+        }
+
+        for (auto &t : threads_) {
+            t.join();
+        }
+    }
+    SPDLOG_CATCH_STD
+}
+
+void SPDLOG_INLINE thread_pool::post_log(async_logger_ptr &&worker_ptr,
+                                         const details::log_msg &msg,
+                                         async_overflow_policy overflow_policy) {
+    async_msg async_m(std::move(worker_ptr), async_msg_type::log, msg);
+    post_async_msg_(std::move(async_m), overflow_policy);
+}
+
+void SPDLOG_INLINE thread_pool::post_flush(async_logger_ptr &&worker_ptr,
+                                           async_overflow_policy overflow_policy) {
+    post_async_msg_(async_msg(std::move(worker_ptr), async_msg_type::flush), overflow_policy);
+}
+
+size_t SPDLOG_INLINE thread_pool::overrun_counter() { return q_.overrun_counter(); }
+
+void SPDLOG_INLINE thread_pool::reset_overrun_counter() { q_.reset_overrun_counter(); }
+
+size_t SPDLOG_INLINE thread_pool::discard_counter() { return q_.discard_counter(); }
+
+void SPDLOG_INLINE thread_pool::reset_discard_counter() { q_.reset_discard_counter(); }
+
+size_t SPDLOG_INLINE thread_pool::queue_size() { return q_.size(); }
+
+void SPDLOG_INLINE thread_pool::post_async_msg_(async_msg &&new_msg,
+                                                async_overflow_policy overflow_policy) {
+    if (overflow_policy == async_overflow_policy::block) {
+        q_.enqueue(std::move(new_msg));
+    } else if (overflow_policy == async_overflow_policy::overrun_oldest) {
+        q_.enqueue_nowait(std::move(new_msg));
+    } else {
+        assert(overflow_policy == async_overflow_policy::discard_new);
+        q_.enqueue_if_have_room(std::move(new_msg));
+    }
+}
+
+void SPDLOG_INLINE thread_pool::worker_loop_() {
+    while (process_next_msg_()) {
+    }
+}
+
+// process next message in the queue
+// return true if this thread should still be active (while no terminate msg
+// was received)
+bool SPDLOG_INLINE thread_pool::process_next_msg_() {
+    async_msg incoming_async_msg;
+    q_.dequeue(incoming_async_msg);
+
+    switch (incoming_async_msg.msg_type) {
+        case async_msg_type::log: {
+            incoming_async_msg.worker_ptr->backend_sink_it_(incoming_async_msg);
+            return true;
+        }
+        case async_msg_type::flush: {
+            incoming_async_msg.worker_ptr->backend_flush_();
+            return true;
+        }
+
+        case async_msg_type::terminate: {
+            return false;
+        }
+
+        default: {
+            assert(false);
+        }
+    }
+
+    return true;
+}
+
+}  // namespace details
+}  // namespace spdlog

spdlog/details/thread_pool.h

@@ -0,0 +1,117 @@
+// Copyright(c) 2015-present, Gabi Melman & spdlog contributors.
+// Distributed under the MIT License (http://opensource.org/licenses/MIT)
+
+#pragma once
+
+#include <spdlog/details/log_msg_buffer.h>
+#include <spdlog/details/mpmc_blocking_q.h>
+#include <spdlog/details/os.h>
+
+#include <chrono>
+#include <functional>
+#include <memory>
+#include <thread>
+#include <vector>
+
+namespace spdlog {
+class async_logger;
+
+namespace details {
+
+using async_logger_ptr = std::shared_ptr<spdlog::async_logger>;
+
+enum class async_msg_type { log, flush, terminate };
+
+// Async msg to move to/from the queue
+// Movable only. should never be copied
+struct async_msg : log_msg_buffer {
+    async_msg_type msg_type{async_msg_type::log};
+    async_logger_ptr worker_ptr;
+
+    async_msg() = default;
+    ~async_msg() = default;
+
+    // should only be moved in or out of the queue..
+    async_msg(const async_msg &) = delete;
+
+// support for vs2013 move
+#if defined(_MSC_VER) && _MSC_VER <= 1800
+    async_msg(async_msg &&other)
+        : log_msg_buffer(std::move(other)),
+          msg_type(other.msg_type),
+          worker_ptr(std::move(other.worker_ptr)) {}
+
+    async_msg &operator=(async_msg &&other) {
+        *static_cast<log_msg_buffer *>(this) = std::move(other);
+        msg_type = other.msg_type;
+        worker_ptr = std::move(other.worker_ptr);
+        return *this;
+    }
+#else  // (_MSC_VER) && _MSC_VER <= 1800
+    async_msg(async_msg &&) = default;
+    async_msg &operator=(async_msg &&) = default;
+#endif
+
+    // construct from log_msg with given type
+    async_msg(async_logger_ptr &&worker, async_msg_type the_type, const details::log_msg &m)
+        : log_msg_buffer{m},
+          msg_type{the_type},
+          worker_ptr{std::move(worker)} {}
+
+    async_msg(async_logger_ptr &&worker, async_msg_type the_type)
+        : log_msg_buffer{},
+          msg_type{the_type},
+          worker_ptr{std::move(worker)} {}
+
+    explicit async_msg(async_msg_type the_type)
+        : async_msg{nullptr, the_type} {}
+};
+
+class SPDLOG_API thread_pool {
+public:
+    using item_type = async_msg;
+    using q_type = details::mpmc_blocking_queue<item_type>;
+
+    thread_pool(size_t q_max_items,
+                size_t threads_n,
+                std::function<void()> on_thread_start,
+                std::function<void()> on_thread_stop);
+    thread_pool(size_t q_max_items, size_t threads_n, std::function<void()> on_thread_start);
+    thread_pool(size_t q_max_items, size_t threads_n);
+
+    // message all threads to terminate gracefully and join them
+    ~thread_pool();
+
+    thread_pool(const thread_pool &) = delete;
+    thread_pool &operator=(thread_pool &&) = delete;
+
+    void post_log(async_logger_ptr &&worker_ptr,
+                  const details::log_msg &msg,
+                  async_overflow_policy overflow_policy);
+    void post_flush(async_logger_ptr &&worker_ptr, async_overflow_policy overflow_policy);
+    size_t overrun_counter();
+    void reset_overrun_counter();
+    size_t discard_counter();
+    void reset_discard_counter();
+    size_t queue_size();
+
+private:
+    q_type q_;
+
+    std::vector<std::thread> threads_;
+
+    void post_async_msg_(async_msg &&new_msg, async_overflow_policy overflow_policy);
+    void worker_loop_();
+
+    // process next message in the queue
+    // return true if this thread should still be active (while no terminate msg
+    // was received)
+    bool process_next_msg_();
+};
+
+}  // namespace details
+}  // namespace spdlog
+
+#ifdef SPDLOG_HEADER_ONLY
+    #include "thread_pool-inl.h"
+#endif

spdlog/details/udp_client-windows.h

@@ -0,0 +1,98 @@
+// Copyright(c) 2015-present, Gabi Melman & spdlog contributors.
+// Distributed under the MIT License (http://opensource.org/licenses/MIT)
+
+#pragma once
+
+// Helper RAII over winsock udp client socket.
+// Will throw on construction if socket creation failed.
+
+#include <spdlog/common.h>
+#include <spdlog/details/os.h>
+#include <spdlog/details/windows_include.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string>
+#include <winsock2.h>
+#include <ws2tcpip.h>
+
+#if defined(_MSC_VER)
+    #pragma comment(lib, "Ws2_32.lib")
+    #pragma comment(lib, "Mswsock.lib")
+    #pragma comment(lib, "AdvApi32.lib")
+#endif
+
+namespace spdlog {
+namespace details {
+class udp_client {
+    static constexpr int TX_BUFFER_SIZE = 1024 * 10;
+    SOCKET socket_ = INVALID_SOCKET;
+    sockaddr_in addr_ = {};
+
+    static void init_winsock_() {
+        WSADATA wsaData;
+        auto rv = ::WSAStartup(MAKEWORD(2, 2), &wsaData);
+        if (rv != 0) {
+            throw_winsock_error_("WSAStartup failed", ::WSAGetLastError());
+        }
+    }
+
+    static void throw_winsock_error_(const std::string &msg, int last_error) {
+        char buf[512];
+        ::FormatMessageA(FORMAT_MESSAGE_FROM_SYSTEM | FORMAT_MESSAGE_IGNORE_INSERTS, NULL,
+                         last_error, MAKELANGID(LANG_NEUTRAL, SUBLANG_DEFAULT), buf,
+                         (sizeof(buf) / sizeof(char)), NULL);
+
+        throw_spdlog_ex(fmt_lib::format("udp_sink - {}: {}", msg, buf));
+    }
+
+    void cleanup_() {
+        if (socket_ != INVALID_SOCKET) {
+            ::closesocket(socket_);
+        }
+        socket_ = INVALID_SOCKET;
+        ::WSACleanup();
+    }
+
+public:
+    udp_client(const std::string &host, uint16_t port) {
+        init_winsock_();
+
+        addr_.sin_family = PF_INET;
+        addr_.sin_port = htons(port);
+        addr_.sin_addr.s_addr = INADDR_ANY;
+        if (InetPtonA(PF_INET, host.c_str(), &addr_.sin_addr.s_addr) != 1) {
+            int last_error = ::WSAGetLastError();
+            ::WSACleanup();
+            throw_winsock_error_("error: Invalid address!", last_error);
+        }
+
+        socket_ = ::socket(PF_INET, SOCK_DGRAM, 0);
+        if (socket_ == INVALID_SOCKET) {
+            int last_error = ::WSAGetLastError();
+            ::WSACleanup();
+            throw_winsock_error_("error: Create Socket failed", last_error);
+        }
+
+        int option_value = TX_BUFFER_SIZE;
+        if (::setsockopt(socket_, SOL_SOCKET, SO_SNDBUF,
+                         reinterpret_cast<const char *>(&option_value), sizeof(option_value)) < 0) {
+            int last_error = ::WSAGetLastError();
+            cleanup_();
+            throw_winsock_error_("error: setsockopt(SO_SNDBUF) Failed!", last_error);
+        }
+    }
+
+    ~udp_client() { cleanup_(); }
+
+    SOCKET fd() const { return socket_; }
+
+    void send(const char *data, size_t n_bytes) {
+        socklen_t tolen = sizeof(struct sockaddr);
+        if (::sendto(socket_, data, static_cast<int>(n_bytes), 0, (struct sockaddr *)&addr_,
+                     tolen) == -1) {
+            throw_spdlog_ex("sendto(2) failed", errno);
+        }
+    }
+};
+}  // namespace details
+}  // namespace spdlog

spdlog/details/udp_client.h

@@ -0,0 +1,81 @@
+// Copyright(c) 2015-present, Gabi Melman & spdlog contributors.
+// Distributed under the MIT License (http://opensource.org/licenses/MIT)
+
+#pragma once
+
+// Helper RAII over unix udp client socket.
+// Will throw on construction if the socket creation failed.
+
+#ifdef _WIN32
+    #error "include udp_client-windows.h instead"
+#endif
+
+#include <arpa/inet.h>
+#include <cstring>
+#include <netdb.h>
+#include <netinet/in.h>
+#include <netinet/udp.h>
+#include <spdlog/common.h>
+#include <spdlog/details/os.h>
+#include <sys/socket.h>
+#include <unistd.h>
+
+#include <string>
+
+namespace spdlog {
+namespace details {
+
+class udp_client {
+    static constexpr int TX_BUFFER_SIZE = 1024 * 10;
+    int socket_ = -1;
+    struct sockaddr_in sockAddr_;
+
+    void cleanup_() {
+        if (socket_ != -1) {
+            ::close(socket_);
+            socket_ = -1;
+        }
+    }
+
+public:
+    udp_client(const std::string &host, uint16_t port) {
+        socket_ = ::socket(PF_INET, SOCK_DGRAM, 0);
+        if (socket_ < 0) {
+            throw_spdlog_ex("error: Create Socket Failed!");
+        }
+
+        int option_value = TX_BUFFER_SIZE;
+        if (::setsockopt(socket_, SOL_SOCKET, SO_SNDBUF,
+                         reinterpret_cast<const char *>(&option_value), sizeof(option_value)) < 0) {
+            cleanup_();
+            throw_spdlog_ex("error: setsockopt(SO_SNDBUF) Failed!");
+        }
+
+        sockAddr_.sin_family = AF_INET;
+        sockAddr_.sin_port = htons(port);
+
+        if (::inet_aton(host.c_str(), &sockAddr_.sin_addr) == 0) {
+            cleanup_();
+            throw_spdlog_ex("error: Invalid address!");
+        }
+
+        ::memset(sockAddr_.sin_zero, 0x00, sizeof(sockAddr_.sin_zero));
+    }
+
+    ~udp_client() { cleanup_(); }
+
+    int fd() const { return socket_; }
+
+    // Send exactly n_bytes of the given data.
+    // On error close the connection and throw.
+    void send(const char *data, size_t n_bytes) {
+        ssize_t toslen = 0;
+        socklen_t tolen = sizeof(struct sockaddr);
+        if ((toslen = ::sendto(socket_, data, n_bytes, 0, (struct sockaddr *)&sockAddr_, tolen)) ==
+            -1) {
+            throw_spdlog_ex("sendto(2) failed", errno);
+        }
+    }
+};
+}  // namespace details
+}  // namespace spdlog

spdlog/details/windows_include.h

@@ -0,0 +1,11 @@
+#pragma once
+
+#ifndef NOMINMAX
+    #define NOMINMAX  // prevent windows redefining min/max
+#endif
+
+#ifndef WIN32_LEAN_AND_MEAN
+    #define WIN32_LEAN_AND_MEAN
+#endif
+
+#include <windows.h>

spdlog/fmt/bin_to_hex.h

@@ -0,0 +1,224 @@
+//
+// Copyright(c) 2015 Gabi Melman.
+// Distributed under the MIT License (http://opensource.org/licenses/MIT)
+//
+
+#pragma once
+
+#include <cctype>
+#include <spdlog/common.h>
+
+#if defined(__has_include)
+    #if __has_include(<version>)
+        #include <version>
+    #endif
+#endif
+
+#if __cpp_lib_span >= 202002L
+    #include <span>
+#endif
+
+//
+// Support for logging binary data as hex
+// format flags, any combination of the following:
+// {:X} - print in uppercase.
+// {:s} - don't separate each byte with space.
+// {:p} - don't print the position on each line start.
+// {:n} - don't split the output to lines.
+// {:a} - show ASCII if :n is not set
+
+//
+// Examples:
+//
+// std::vector<char> v(200, 0x0b);
+// logger->info("Some buffer {}", spdlog::to_hex(v));
+// char buf[128];
+// logger->info("Some buffer {:X}", spdlog::to_hex(std::begin(buf), std::end(buf)));
+// logger->info("Some buffer {:X}", spdlog::to_hex(std::begin(buf), std::end(buf), 16));
+
+namespace spdlog {
+namespace details {
+
+template <typename It>
+class dump_info {
+public:
+    dump_info(It range_begin, It range_end, size_t size_per_line)
+        : begin_(range_begin),
+          end_(range_end),
+          size_per_line_(size_per_line) {}
+
+    // do not use begin() and end() to avoid collision with fmt/ranges
+    It get_begin() const { return begin_; }
+    It get_end() const { return end_; }
+    size_t size_per_line() const { return size_per_line_; }
+
+private:
+    It begin_, end_;
+    size_t size_per_line_;
+};
+}  // namespace details
+
+// create a dump_info that wraps the given container
+template <typename Container>
+inline details::dump_info<typename Container::const_iterator> to_hex(const Container &container,
+                                                                     size_t size_per_line = 32) {
+    static_assert(sizeof(typename Container::value_type) == 1,
+                  "sizeof(Container::value_type) != 1");
+    using Iter = typename Container::const_iterator;
+    return details::dump_info<Iter>(std::begin(container), std::end(container), size_per_line);
+}
+
+#if __cpp_lib_span >= 202002L
+
+template <typename Value, size_t Extent>
+inline details::dump_info<typename std::span<Value, Extent>::iterator> to_hex(
+    const std::span<Value, Extent> &container, size_t size_per_line = 32) {
+    using Container = std::span<Value, Extent>;
+    static_assert(sizeof(typename Container::value_type) == 1,
+                  "sizeof(Container::value_type) != 1");
+    using Iter = typename Container::iterator;
+    return details::dump_info<Iter>(std::begin(container), std::end(container), size_per_line);
+}
+
+#endif
+
+// create dump_info from ranges
+template <typename It>
+inline details::dump_info<It> to_hex(const It range_begin,
+                                     const It range_end,
+                                     size_t size_per_line = 32) {
+    return details::dump_info<It>(range_begin, range_end, size_per_line);
+}
+
+}  // namespace spdlog
+
+namespace
+#ifdef SPDLOG_USE_STD_FORMAT
+    std
+#else
+    fmt
+#endif
+{
+
+template <typename T>
+struct formatter<spdlog::details::dump_info<T>, char> {
+    char delimiter = ' ';
+    bool put_newlines = true;
+    bool put_delimiters = true;
+    bool use_uppercase = false;
+    bool put_positions = true;  // position on start of each line
+    bool show_ascii = false;
+
+    // parse the format string flags
+    template <typename ParseContext>
+    SPDLOG_CONSTEXPR_FUNC auto parse(ParseContext &ctx) -> decltype(ctx.begin()) {
+        auto it = ctx.begin();
+        while (it != ctx.end() && *it != '}') {
+            switch (*it) {
+                case 'X':
+                    use_uppercase = true;
+                    break;
+                case 's':
+                    put_delimiters = false;
+                    break;
+                case 'p':
+                    put_positions = false;
+                    break;
+                case 'n':
+                    put_newlines = false;
+                    show_ascii = false;
+                    break;
+                case 'a':
+                    if (put_newlines) {
+                        show_ascii = true;
+                    }
+                    break;
+            }
+
+            ++it;
+        }
+        return it;
+    }
+
+    // format the given bytes range as hex
+    template <typename FormatContext, typename Container>
+    auto format(const spdlog::details::dump_info<Container> &the_range, FormatContext &ctx) const
+        -> decltype(ctx.out()) {
+        SPDLOG_CONSTEXPR const char *hex_upper = "0123456789ABCDEF";
+        SPDLOG_CONSTEXPR const char *hex_lower = "0123456789abcdef";
+        const char *hex_chars = use_uppercase ? hex_upper : hex_lower;
+
+#if !defined(SPDLOG_USE_STD_FORMAT) && FMT_VERSION < 60000
+        auto inserter = ctx.begin();
+#else
+        auto inserter = ctx.out();
+#endif
+
+        int size_per_line = static_cast<int>(the_range.size_per_line());
+        auto start_of_line = the_range.get_begin();
+        for (auto i = the_range.get_begin(); i != the_range.get_end(); i++) {
+            auto ch = static_cast<unsigned char>(*i);
+
+            if (put_newlines &&
+                (i == the_range.get_begin() || i - start_of_line >= size_per_line)) {
+                if (show_ascii && i != the_range.get_begin()) {
+                    *inserter++ = delimiter;
+                    *inserter++ = delimiter;
+                    for (auto j = start_of_line; j < i; j++) {
+                        auto pc = static_cast<unsigned char>(*j);
+                        *inserter++ = std::isprint(pc) ? static_cast<char>(*j) : '.';
+                    }
+                }
+
+                put_newline(inserter, static_cast<size_t>(i - the_range.get_begin()));
+
+                // put first byte without delimiter in front of it
+                *inserter++ = hex_chars[(ch >> 4) & 0x0f];
+                *inserter++ = hex_chars[ch & 0x0f];
+                start_of_line = i;
+                continue;
+            }
+
+            if (put_delimiters && i != the_range.get_begin()) {
+                *inserter++ = delimiter;
+            }
+
+            *inserter++ = hex_chars[(ch >> 4) & 0x0f];
+            *inserter++ = hex_chars[ch & 0x0f];
+        }
+        if (show_ascii)  // add ascii to last line
+        {
+            if (the_range.get_end() - the_range.get_begin() > size_per_line) {
+                auto blank_num = size_per_line - (the_range.get_end() - start_of_line);
+                while (blank_num-- > 0) {
+                    *inserter++ = delimiter;
+                    *inserter++ = delimiter;
+                    if (put_delimiters) {
+                        *inserter++ = delimiter;
+                    }
+                }
+            }
+            *inserter++ = delimiter;
+            *inserter++ = delimiter;
+            for (auto j = start_of_line; j != the_range.get_end(); j++) {
+                auto pc = static_cast<unsigned char>(*j);
+                *inserter++ = std::isprint(pc) ? static_cast<char>(*j) : '.';
+            }
+        }
+        return inserter;
+    }
+
+    // put newline(and position header)
+    template <typename It>
+    void put_newline(It inserter, std::size_t pos) const {
+#ifdef _WIN32
+        *inserter++ = '\r';
+#endif
+        *inserter++ = '\n';
+
+        if (put_positions) {
+            spdlog::fmt_lib::format_to(inserter, SPDLOG_FMT_STRING("{:04X}: "), pos);
+        }
+    }
+};
+}  // namespace std

spdlog/fmt/bundled/args.h

@@ -0,0 +1,220 @@
+// Formatting library for C++ - dynamic argument lists
+//
+// Copyright (c) 2012 - present, Victor Zverovich
+// All rights reserved.
+//
+// For the license information refer to format.h.
+
+#ifndef FMT_ARGS_H_
+#define FMT_ARGS_H_
+
+#ifndef FMT_MODULE
+#  include <functional>  // std::reference_wrapper
+#  include <memory>      // std::unique_ptr
+#  include <vector>
+#endif
+
+#include "format.h"  // std_string_view
+
+FMT_BEGIN_NAMESPACE
+namespace detail {
+
+template <typename T> struct is_reference_wrapper : std::false_type {};
+template <typename T>
+struct is_reference_wrapper<std::reference_wrapper<T>> : std::true_type {};
+
+template <typename T> auto unwrap(const T& v) -> const T& { return v; }
+template <typename T>
+auto unwrap(const std::reference_wrapper<T>& v) -> const T& {
+  return static_cast<const T&>(v);
+}
+
+// node is defined outside dynamic_arg_list to workaround a C2504 bug in MSVC
+// 2022 (v17.10.0).
+//
+// Workaround for clang's -Wweak-vtables. Unlike for regular classes, for
+// templates it doesn't complain about inability to deduce single translation
+// unit for placing vtable. So node is made a fake template.
+template <typename = void> struct node {
+  virtual ~node() = default;
+  std::unique_ptr<node<>> next;
+};
+
+class dynamic_arg_list {
+  template <typename T> struct typed_node : node<> {
+    T value;
+
+    template <typename Arg>
+    FMT_CONSTEXPR typed_node(const Arg& arg) : value(arg) {}
+
+    template <typename Char>
+    FMT_CONSTEXPR typed_node(const basic_string_view<Char>& arg)
+        : value(arg.data(), arg.size()) {}
+  };
+
+  std::unique_ptr<node<>> head_;
+
+ public:
+  template <typename T, typename Arg> auto push(const Arg& arg) -> const T& {
+    auto new_node = std::unique_ptr<typed_node<T>>(new typed_node<T>(arg));
+    auto& value = new_node->value;
+    new_node->next = std::move(head_);
+    head_ = std::move(new_node);
+    return value;
+  }
+};
+}  // namespace detail
+
+/**
+ * A dynamic list of formatting arguments with storage.
+ *
+ * It can be implicitly converted into `fmt::basic_format_args` for passing
+ * into type-erased formatting functions such as `fmt::vformat`.
+ */
+template <typename Context> class dynamic_format_arg_store {
+ private:
+  using char_type = typename Context::char_type;
+
+  template <typename T> struct need_copy {
+    static constexpr detail::type mapped_type =
+        detail::mapped_type_constant<T, char_type>::value;
+
+    enum {
+      value = !(detail::is_reference_wrapper<T>::value ||
+                std::is_same<T, basic_string_view<char_type>>::value ||
+                std::is_same<T, detail::std_string_view<char_type>>::value ||
+                (mapped_type != detail::type::cstring_type &&
+                 mapped_type != detail::type::string_type &&
+                 mapped_type != detail::type::custom_type))
+    };
+  };
+
+  template <typename T>
+  using stored_t = conditional_t<
+      std::is_convertible<T, std::basic_string<char_type>>::value &&
+          !detail::is_reference_wrapper<T>::value,
+      std::basic_string<char_type>, T>;
+
+  // Storage of basic_format_arg must be contiguous.
+  std::vector<basic_format_arg<Context>> data_;
+  std::vector<detail::named_arg_info<char_type>> named_info_;
+
+  // Storage of arguments not fitting into basic_format_arg must grow
+  // without relocation because items in data_ refer to it.
+  detail::dynamic_arg_list dynamic_args_;
+
+  friend class basic_format_args<Context>;
+
+  auto data() const -> const basic_format_arg<Context>* {
+    return named_info_.empty() ? data_.data() : data_.data() + 1;
+  }
+
+  template <typename T> void emplace_arg(const T& arg) {
+    data_.emplace_back(arg);
+  }
+
+  template <typename T>
+  void emplace_arg(const detail::named_arg<char_type, T>& arg) {
+    if (named_info_.empty())
+      data_.insert(data_.begin(), basic_format_arg<Context>(nullptr, 0));
+    data_.emplace_back(detail::unwrap(arg.value));
+    auto pop_one = [](std::vector<basic_format_arg<Context>>* data) {
+      data->pop_back();
+    };
+    std::unique_ptr<std::vector<basic_format_arg<Context>>, decltype(pop_one)>
+        guard{&data_, pop_one};
+    named_info_.push_back({arg.name, static_cast<int>(data_.size() - 2u)});
+    data_[0] = {named_info_.data(), named_info_.size()};
+    guard.release();
+  }
+
+ public:
+  constexpr dynamic_format_arg_store() = default;
+
+  operator basic_format_args<Context>() const {
+    return basic_format_args<Context>(data(), static_cast<int>(data_.size()),
+                                      !named_info_.empty());
+  }
+
+  /**
+   * Adds an argument into the dynamic store for later passing to a formatting
+   * function.
+   *
+   * Note that custom types and string types (but not string views) are copied
+   * into the store dynamically allocating memory if necessary.
+   *
+   * **Example**:
+   *
+   *     fmt::dynamic_format_arg_store<fmt::format_context> store;
+   *     store.push_back(42);
+   *     store.push_back("abc");
+   *     store.push_back(1.5f);
+   *     std::string result = fmt::vformat("{} and {} and {}", store);
+   */
+  template <typename T> void push_back(const T& arg) {
+    if (detail::const_check(need_copy<T>::value))
+      emplace_arg(dynamic_args_.push<stored_t<T>>(arg));
+    else
+      emplace_arg(detail::unwrap(arg));
+  }
+
+  /**
+   * Adds a reference to the argument into the dynamic store for later passing
+   * to a formatting function.
+   *
+   * **Example**:
+   *
+   *     fmt::dynamic_format_arg_store<fmt::format_context> store;
+   *     char band[] = "Rolling Stones";
+   *     store.push_back(std::cref(band));
+   *     band[9] = 'c'; // Changing str affects the output.
+   *     std::string result = fmt::vformat("{}", store);
+   *     // result == "Rolling Scones"
+   */
+  template <typename T> void push_back(std::reference_wrapper<T> arg) {
+    static_assert(
+        need_copy<T>::value,
+        "objects of built-in types and string views are always copied");
+    emplace_arg(arg.get());
+  }
+
+  /**
+   * Adds named argument into the dynamic store for later passing to a
+   * formatting function. `std::reference_wrapper` is supported to avoid
+   * copying of the argument. The name is always copied into the store.
+   */
+  template <typename T>
+  void push_back(const detail::named_arg<char_type, T>& arg) {
+    const char_type* arg_name =
+        dynamic_args_.push<std::basic_string<char_type>>(arg.name).c_str();
+    if (detail::const_check(need_copy<T>::value)) {
+      emplace_arg(
+          fmt::arg(arg_name, dynamic_args_.push<stored_t<T>>(arg.value)));
+    } else {
+      emplace_arg(fmt::arg(arg_name, arg.value));
+    }
+  }
+
+  /// Erase all elements from the store.
+  void clear() {
+    data_.clear();
+    named_info_.clear();
+    dynamic_args_ = {};
+  }
+
+  /// Reserves space to store at least `new_cap` arguments including
+  /// `new_cap_named` named arguments.
+  void reserve(size_t new_cap, size_t new_cap_named) {
+    FMT_ASSERT(new_cap >= new_cap_named,
+               "set of arguments includes set of named arguments");
+    data_.reserve(new_cap);
+    named_info_.reserve(new_cap_named);
+  }
+
+  /// Returns the number of elements in the store.
+  size_t size() const noexcept { return data_.size(); }
+};
+
+FMT_END_NAMESPACE
+
+#endif  // FMT_ARGS_H_

spdlog/fmt/bundled/color.h

@@ -0,0 +1,610 @@
+// Formatting library for C++ - color support
+//
+// Copyright (c) 2018 - present, Victor Zverovich and fmt contributors
+// All rights reserved.
+//
+// For the license information refer to format.h.
+
+#ifndef FMT_COLOR_H_
+#define FMT_COLOR_H_
+
+#include "format.h"
+
+FMT_BEGIN_NAMESPACE
+FMT_BEGIN_EXPORT
+
+enum class color : uint32_t {
+  alice_blue = 0xF0F8FF,               // rgb(240,248,255)
+  antique_white = 0xFAEBD7,            // rgb(250,235,215)
+  aqua = 0x00FFFF,                     // rgb(0,255,255)
+  aquamarine = 0x7FFFD4,               // rgb(127,255,212)
+  azure = 0xF0FFFF,                    // rgb(240,255,255)
+  beige = 0xF5F5DC,                    // rgb(245,245,220)
+  bisque = 0xFFE4C4,                   // rgb(255,228,196)
+  black = 0x000000,                    // rgb(0,0,0)
+  blanched_almond = 0xFFEBCD,          // rgb(255,235,205)
+  blue = 0x0000FF,                     // rgb(0,0,255)
+  blue_violet = 0x8A2BE2,              // rgb(138,43,226)
+  brown = 0xA52A2A,                    // rgb(165,42,42)
+  burly_wood = 0xDEB887,               // rgb(222,184,135)
+  cadet_blue = 0x5F9EA0,               // rgb(95,158,160)
+  chartreuse = 0x7FFF00,               // rgb(127,255,0)
+  chocolate = 0xD2691E,                // rgb(210,105,30)
+  coral = 0xFF7F50,                    // rgb(255,127,80)
+  cornflower_blue = 0x6495ED,          // rgb(100,149,237)
+  cornsilk = 0xFFF8DC,                 // rgb(255,248,220)
+  crimson = 0xDC143C,                  // rgb(220,20,60)
+  cyan = 0x00FFFF,                     // rgb(0,255,255)
+  dark_blue = 0x00008B,                // rgb(0,0,139)
+  dark_cyan = 0x008B8B,                // rgb(0,139,139)
+  dark_golden_rod = 0xB8860B,          // rgb(184,134,11)
+  dark_gray = 0xA9A9A9,                // rgb(169,169,169)
+  dark_green = 0x006400,               // rgb(0,100,0)
+  dark_khaki = 0xBDB76B,               // rgb(189,183,107)
+  dark_magenta = 0x8B008B,             // rgb(139,0,139)
+  dark_olive_green = 0x556B2F,         // rgb(85,107,47)
+  dark_orange = 0xFF8C00,              // rgb(255,140,0)
+  dark_orchid = 0x9932CC,              // rgb(153,50,204)
+  dark_red = 0x8B0000,                 // rgb(139,0,0)
+  dark_salmon = 0xE9967A,              // rgb(233,150,122)
+  dark_sea_green = 0x8FBC8F,           // rgb(143,188,143)
+  dark_slate_blue = 0x483D8B,          // rgb(72,61,139)
+  dark_slate_gray = 0x2F4F4F,          // rgb(47,79,79)
+  dark_turquoise = 0x00CED1,           // rgb(0,206,209)
+  dark_violet = 0x9400D3,              // rgb(148,0,211)
+  deep_pink = 0xFF1493,                // rgb(255,20,147)
+  deep_sky_blue = 0x00BFFF,            // rgb(0,191,255)
+  dim_gray = 0x696969,                 // rgb(105,105,105)
+  dodger_blue = 0x1E90FF,              // rgb(30,144,255)
+  fire_brick = 0xB22222,               // rgb(178,34,34)
+  floral_white = 0xFFFAF0,             // rgb(255,250,240)
+  forest_green = 0x228B22,             // rgb(34,139,34)
+  fuchsia = 0xFF00FF,                  // rgb(255,0,255)
+  gainsboro = 0xDCDCDC,                // rgb(220,220,220)
+  ghost_white = 0xF8F8FF,              // rgb(248,248,255)
+  gold = 0xFFD700,                     // rgb(255,215,0)
+  golden_rod = 0xDAA520,               // rgb(218,165,32)
+  gray = 0x808080,                     // rgb(128,128,128)
+  green = 0x008000,                    // rgb(0,128,0)
+  green_yellow = 0xADFF2F,             // rgb(173,255,47)
+  honey_dew = 0xF0FFF0,                // rgb(240,255,240)
+  hot_pink = 0xFF69B4,                 // rgb(255,105,180)
+  indian_red = 0xCD5C5C,               // rgb(205,92,92)
+  indigo = 0x4B0082,                   // rgb(75,0,130)
+  ivory = 0xFFFFF0,                    // rgb(255,255,240)
+  khaki = 0xF0E68C,                    // rgb(240,230,140)
+  lavender = 0xE6E6FA,                 // rgb(230,230,250)
+  lavender_blush = 0xFFF0F5,           // rgb(255,240,245)
+  lawn_green = 0x7CFC00,               // rgb(124,252,0)
+  lemon_chiffon = 0xFFFACD,            // rgb(255,250,205)
+  light_blue = 0xADD8E6,               // rgb(173,216,230)
+  light_coral = 0xF08080,              // rgb(240,128,128)
+  light_cyan = 0xE0FFFF,               // rgb(224,255,255)
+  light_golden_rod_yellow = 0xFAFAD2,  // rgb(250,250,210)
+  light_gray = 0xD3D3D3,               // rgb(211,211,211)
+  light_green = 0x90EE90,              // rgb(144,238,144)
+  light_pink = 0xFFB6C1,               // rgb(255,182,193)
+  light_salmon = 0xFFA07A,             // rgb(255,160,122)
+  light_sea_green = 0x20B2AA,          // rgb(32,178,170)
+  light_sky_blue = 0x87CEFA,           // rgb(135,206,250)
+  light_slate_gray = 0x778899,         // rgb(119,136,153)
+  light_steel_blue = 0xB0C4DE,         // rgb(176,196,222)
+  light_yellow = 0xFFFFE0,             // rgb(255,255,224)
+  lime = 0x00FF00,                     // rgb(0,255,0)
+  lime_green = 0x32CD32,               // rgb(50,205,50)
+  linen = 0xFAF0E6,                    // rgb(250,240,230)
+  magenta = 0xFF00FF,                  // rgb(255,0,255)
+  maroon = 0x800000,                   // rgb(128,0,0)
+  medium_aquamarine = 0x66CDAA,        // rgb(102,205,170)
+  medium_blue = 0x0000CD,              // rgb(0,0,205)
+  medium_orchid = 0xBA55D3,            // rgb(186,85,211)
+  medium_purple = 0x9370DB,            // rgb(147,112,219)
+  medium_sea_green = 0x3CB371,         // rgb(60,179,113)
+  medium_slate_blue = 0x7B68EE,        // rgb(123,104,238)
+  medium_spring_green = 0x00FA9A,      // rgb(0,250,154)
+  medium_turquoise = 0x48D1CC,         // rgb(72,209,204)
+  medium_violet_red = 0xC71585,        // rgb(199,21,133)
+  midnight_blue = 0x191970,            // rgb(25,25,112)
+  mint_cream = 0xF5FFFA,               // rgb(245,255,250)
+  misty_rose = 0xFFE4E1,               // rgb(255,228,225)
+  moccasin = 0xFFE4B5,                 // rgb(255,228,181)
+  navajo_white = 0xFFDEAD,             // rgb(255,222,173)
+  navy = 0x000080,                     // rgb(0,0,128)
+  old_lace = 0xFDF5E6,                 // rgb(253,245,230)
+  olive = 0x808000,                    // rgb(128,128,0)
+  olive_drab = 0x6B8E23,               // rgb(107,142,35)
+  orange = 0xFFA500,                   // rgb(255,165,0)
+  orange_red = 0xFF4500,               // rgb(255,69,0)
+  orchid = 0xDA70D6,                   // rgb(218,112,214)
+  pale_golden_rod = 0xEEE8AA,          // rgb(238,232,170)
+  pale_green = 0x98FB98,               // rgb(152,251,152)
+  pale_turquoise = 0xAFEEEE,           // rgb(175,238,238)
+  pale_violet_red = 0xDB7093,          // rgb(219,112,147)
+  papaya_whip = 0xFFEFD5,              // rgb(255,239,213)
+  peach_puff = 0xFFDAB9,               // rgb(255,218,185)
+  peru = 0xCD853F,                     // rgb(205,133,63)
+  pink = 0xFFC0CB,                     // rgb(255,192,203)
+  plum = 0xDDA0DD,                     // rgb(221,160,221)
+  powder_blue = 0xB0E0E6,              // rgb(176,224,230)
+  purple = 0x800080,                   // rgb(128,0,128)
+  rebecca_purple = 0x663399,           // rgb(102,51,153)
+  red = 0xFF0000,                      // rgb(255,0,0)
+  rosy_brown = 0xBC8F8F,               // rgb(188,143,143)
+  royal_blue = 0x4169E1,               // rgb(65,105,225)
+  saddle_brown = 0x8B4513,             // rgb(139,69,19)
+  salmon = 0xFA8072,                   // rgb(250,128,114)
+  sandy_brown = 0xF4A460,              // rgb(244,164,96)
+  sea_green = 0x2E8B57,                // rgb(46,139,87)
+  sea_shell = 0xFFF5EE,                // rgb(255,245,238)
+  sienna = 0xA0522D,                   // rgb(160,82,45)
+  silver = 0xC0C0C0,                   // rgb(192,192,192)
+  sky_blue = 0x87CEEB,                 // rgb(135,206,235)
+  slate_blue = 0x6A5ACD,               // rgb(106,90,205)
+  slate_gray = 0x708090,               // rgb(112,128,144)
+  snow = 0xFFFAFA,                     // rgb(255,250,250)
+  spring_green = 0x00FF7F,             // rgb(0,255,127)
+  steel_blue = 0x4682B4,               // rgb(70,130,180)
+  tan = 0xD2B48C,                      // rgb(210,180,140)
+  teal = 0x008080,                     // rgb(0,128,128)
+  thistle = 0xD8BFD8,                  // rgb(216,191,216)
+  tomato = 0xFF6347,                   // rgb(255,99,71)
+  turquoise = 0x40E0D0,                // rgb(64,224,208)
+  violet = 0xEE82EE,                   // rgb(238,130,238)
+  wheat = 0xF5DEB3,                    // rgb(245,222,179)
+  white = 0xFFFFFF,                    // rgb(255,255,255)
+  white_smoke = 0xF5F5F5,              // rgb(245,245,245)
+  yellow = 0xFFFF00,                   // rgb(255,255,0)
+  yellow_green = 0x9ACD32              // rgb(154,205,50)
+};                                     // enum class color
+
+enum class terminal_color : uint8_t {
+  black = 30,
+  red,
+  green,
+  yellow,
+  blue,
+  magenta,
+  cyan,
+  white,
+  bright_black = 90,
+  bright_red,
+  bright_green,
+  bright_yellow,
+  bright_blue,
+  bright_magenta,
+  bright_cyan,
+  bright_white
+};
+
+enum class emphasis : uint8_t {
+  bold = 1,
+  faint = 1 << 1,
+  italic = 1 << 2,
+  underline = 1 << 3,
+  blink = 1 << 4,
+  reverse = 1 << 5,
+  conceal = 1 << 6,
+  strikethrough = 1 << 7,
+};
+
+// rgb is a struct for red, green and blue colors.
+// Using the name "rgb" makes some editors show the color in a tooltip.
+struct rgb {
+  FMT_CONSTEXPR rgb() : r(0), g(0), b(0) {}
+  FMT_CONSTEXPR rgb(uint8_t r_, uint8_t g_, uint8_t b_) : r(r_), g(g_), b(b_) {}
+  FMT_CONSTEXPR rgb(uint32_t hex)
+      : r((hex >> 16) & 0xFF), g((hex >> 8) & 0xFF), b(hex & 0xFF) {}
+  FMT_CONSTEXPR rgb(color hex)
+      : r((uint32_t(hex) >> 16) & 0xFF),
+        g((uint32_t(hex) >> 8) & 0xFF),
+        b(uint32_t(hex) & 0xFF) {}
+  uint8_t r;
+  uint8_t g;
+  uint8_t b;
+};
+
+namespace detail {
+
+// color is a struct of either a rgb color or a terminal color.
+struct color_type {
+  FMT_CONSTEXPR color_type() noexcept : is_rgb(), value{} {}
+  FMT_CONSTEXPR color_type(color rgb_color) noexcept : is_rgb(true), value{} {
+    value.rgb_color = static_cast<uint32_t>(rgb_color);
+  }
+  FMT_CONSTEXPR color_type(rgb rgb_color) noexcept : is_rgb(true), value{} {
+    value.rgb_color = (static_cast<uint32_t>(rgb_color.r) << 16) |
+                      (static_cast<uint32_t>(rgb_color.g) << 8) | rgb_color.b;
+  }
+  FMT_CONSTEXPR color_type(terminal_color term_color) noexcept
+      : is_rgb(), value{} {
+    value.term_color = static_cast<uint8_t>(term_color);
+  }
+  bool is_rgb;
+  union color_union {
+    uint8_t term_color;
+    uint32_t rgb_color;
+  } value;
+};
+}  // namespace detail
+
+/// A text style consisting of foreground and background colors and emphasis.
+class text_style {
+ public:
+  FMT_CONSTEXPR text_style(emphasis em = emphasis()) noexcept
+      : set_foreground_color(), set_background_color(), ems(em) {}
+
+  FMT_CONSTEXPR auto operator|=(const text_style& rhs) -> text_style& {
+    if (!set_foreground_color) {
+      set_foreground_color = rhs.set_foreground_color;
+      foreground_color = rhs.foreground_color;
+    } else if (rhs.set_foreground_color) {
+      if (!foreground_color.is_rgb || !rhs.foreground_color.is_rgb)
+        report_error("can't OR a terminal color");
+      foreground_color.value.rgb_color |= rhs.foreground_color.value.rgb_color;
+    }
+
+    if (!set_background_color) {
+      set_background_color = rhs.set_background_color;
+      background_color = rhs.background_color;
+    } else if (rhs.set_background_color) {
+      if (!background_color.is_rgb || !rhs.background_color.is_rgb)
+        report_error("can't OR a terminal color");
+      background_color.value.rgb_color |= rhs.background_color.value.rgb_color;
+    }
+
+    ems = static_cast<emphasis>(static_cast<uint8_t>(ems) |
+                                static_cast<uint8_t>(rhs.ems));
+    return *this;
+  }
+
+  friend FMT_CONSTEXPR auto operator|(text_style lhs, const text_style& rhs)
+      -> text_style {
+    return lhs |= rhs;
+  }
+
+  FMT_CONSTEXPR auto has_foreground() const noexcept -> bool {
+    return set_foreground_color;
+  }
+  FMT_CONSTEXPR auto has_background() const noexcept -> bool {
+    return set_background_color;
+  }
+  FMT_CONSTEXPR auto has_emphasis() const noexcept -> bool {
+    return static_cast<uint8_t>(ems) != 0;
+  }
+  FMT_CONSTEXPR auto get_foreground() const noexcept -> detail::color_type {
+    FMT_ASSERT(has_foreground(), "no foreground specified for this style");
+    return foreground_color;
+  }
+  FMT_CONSTEXPR auto get_background() const noexcept -> detail::color_type {
+    FMT_ASSERT(has_background(), "no background specified for this style");
+    return background_color;
+  }
+  FMT_CONSTEXPR auto get_emphasis() const noexcept -> emphasis {
+    FMT_ASSERT(has_emphasis(), "no emphasis specified for this style");
+    return ems;
+  }
+
+ private:
+  FMT_CONSTEXPR text_style(bool is_foreground,
+                           detail::color_type text_color) noexcept
+      : set_foreground_color(), set_background_color(), ems() {
+    if (is_foreground) {
+      foreground_color = text_color;
+      set_foreground_color = true;
+    } else {
+      background_color = text_color;
+      set_background_color = true;
+    }
+  }
+
+  friend FMT_CONSTEXPR auto fg(detail::color_type foreground) noexcept
+      -> text_style;
+
+  friend FMT_CONSTEXPR auto bg(detail::color_type background) noexcept
+      -> text_style;
+
+  detail::color_type foreground_color;
+  detail::color_type background_color;
+  bool set_foreground_color;
+  bool set_background_color;
+  emphasis ems;
+};
+
+/// Creates a text style from the foreground (text) color.
+FMT_CONSTEXPR inline auto fg(detail::color_type foreground) noexcept
+    -> text_style {
+  return text_style(true, foreground);
+}
+
+/// Creates a text style from the background color.
+FMT_CONSTEXPR inline auto bg(detail::color_type background) noexcept
+    -> text_style {
+  return text_style(false, background);
+}
+
+FMT_CONSTEXPR inline auto operator|(emphasis lhs, emphasis rhs) noexcept
+    -> text_style {
+  return text_style(lhs) | rhs;
+}
+
+namespace detail {
+
+template <typename Char> struct ansi_color_escape {
+  FMT_CONSTEXPR ansi_color_escape(color_type text_color,
+                                  const char* esc) noexcept {
+    // If we have a terminal color, we need to output another escape code
+    // sequence.
+    if (!text_color.is_rgb) {
+      bool is_background = esc == string_view("\x1b[48;2;");
+      uint32_t value = text_color.value.term_color;
+      // Background ASCII codes are the same as the foreground ones but with
+      // 10 more.
+      if (is_background) value += 10u;
+
+      size_t index = 0;
+      buffer[index++] = static_cast<Char>('\x1b');
+      buffer[index++] = static_cast<Char>('[');
+
+      if (value >= 100u) {
+        buffer[index++] = static_cast<Char>('1');
+        value %= 100u;
+      }
+      buffer[index++] = static_cast<Char>('0' + value / 10u);
+      buffer[index++] = static_cast<Char>('0' + value % 10u);
+
+      buffer[index++] = static_cast<Char>('m');
+      buffer[index++] = static_cast<Char>('\0');
+      return;
+    }
+
+    for (int i = 0; i < 7; i++) {
+      buffer[i] = static_cast<Char>(esc[i]);
+    }
+    rgb color(text_color.value.rgb_color);
+    to_esc(color.r, buffer + 7, ';');
+    to_esc(color.g, buffer + 11, ';');
+    to_esc(color.b, buffer + 15, 'm');
+    buffer[19] = static_cast<Char>(0);
+  }
+  FMT_CONSTEXPR ansi_color_escape(emphasis em) noexcept {
+    uint8_t em_codes[num_emphases] = {};
+    if (has_emphasis(em, emphasis::bold)) em_codes[0] = 1;
+    if (has_emphasis(em, emphasis::faint)) em_codes[1] = 2;
+    if (has_emphasis(em, emphasis::italic)) em_codes[2] = 3;
+    if (has_emphasis(em, emphasis::underline)) em_codes[3] = 4;
+    if (has_emphasis(em, emphasis::blink)) em_codes[4] = 5;
+    if (has_emphasis(em, emphasis::reverse)) em_codes[5] = 7;
+    if (has_emphasis(em, emphasis::conceal)) em_codes[6] = 8;
+    if (has_emphasis(em, emphasis::strikethrough)) em_codes[7] = 9;
+
+    size_t index = 0;
+    for (size_t i = 0; i < num_emphases; ++i) {
+      if (!em_codes[i]) continue;
+      buffer[index++] = static_cast<Char>('\x1b');
+      buffer[index++] = static_cast<Char>('[');
+      buffer[index++] = static_cast<Char>('0' + em_codes[i]);
+      buffer[index++] = static_cast<Char>('m');
+    }
+    buffer[index++] = static_cast<Char>(0);
+  }
+  FMT_CONSTEXPR operator const Char*() const noexcept { return buffer; }
+
+  FMT_CONSTEXPR auto begin() const noexcept -> const Char* { return buffer; }
+  FMT_CONSTEXPR20 auto end() const noexcept -> const Char* {
+    return buffer + basic_string_view<Char>(buffer).size();
+  }
+
+ private:
+  static constexpr size_t num_emphases = 8;
+  Char buffer[7u + 3u * num_emphases + 1u];
+
+  static FMT_CONSTEXPR void to_esc(uint8_t c, Char* out,
+                                   char delimiter) noexcept {
+    out[0] = static_cast<Char>('0' + c / 100);
+    out[1] = static_cast<Char>('0' + c / 10 % 10);
+    out[2] = static_cast<Char>('0' + c % 10);
+    out[3] = static_cast<Char>(delimiter);
+  }
+  static FMT_CONSTEXPR auto has_emphasis(emphasis em, emphasis mask) noexcept
+      -> bool {
+    return static_cast<uint8_t>(em) & static_cast<uint8_t>(mask);
+  }
+};
+
+template <typename Char>
+FMT_CONSTEXPR auto make_foreground_color(color_type foreground) noexcept
+    -> ansi_color_escape<Char> {
+  return ansi_color_escape<Char>(foreground, "\x1b[38;2;");
+}
+
+template <typename Char>
+FMT_CONSTEXPR auto make_background_color(color_type background) noexcept
+    -> ansi_color_escape<Char> {
+  return ansi_color_escape<Char>(background, "\x1b[48;2;");
+}
+
+template <typename Char>
+FMT_CONSTEXPR auto make_emphasis(emphasis em) noexcept
+    -> ansi_color_escape<Char> {
+  return ansi_color_escape<Char>(em);
+}
+
+template <typename Char> inline void reset_color(buffer<Char>& buffer) {
+  auto reset_color = string_view("\x1b[0m");
+  buffer.append(reset_color.begin(), reset_color.end());
+}
+
+template <typename T> struct styled_arg : view {
+  const T& value;
+  text_style style;
+  styled_arg(const T& v, text_style s) : value(v), style(s) {}
+};
+
+template <typename Char>
+void vformat_to(buffer<Char>& buf, const text_style& ts,
+                basic_string_view<Char> fmt,
+                basic_format_args<buffered_context<Char>> args) {
+  bool has_style = false;
+  if (ts.has_emphasis()) {
+    has_style = true;
+    auto emphasis = make_emphasis<Char>(ts.get_emphasis());
+    buf.append(emphasis.begin(), emphasis.end());
+  }
+  if (ts.has_foreground()) {
+    has_style = true;
+    auto foreground = make_foreground_color<Char>(ts.get_foreground());
+    buf.append(foreground.begin(), foreground.end());
+  }
+  if (ts.has_background()) {
+    has_style = true;
+    auto background = make_background_color<Char>(ts.get_background());
+    buf.append(background.begin(), background.end());
+  }
+  vformat_to(buf, fmt, args);
+  if (has_style) reset_color<Char>(buf);
+}
+}  // namespace detail
+
+inline void vprint(FILE* f, const text_style& ts, string_view fmt,
+                   format_args args) {
+  auto buf = memory_buffer();
+  detail::vformat_to(buf, ts, fmt, args);
+  print(f, FMT_STRING("{}"), string_view(buf.begin(), buf.size()));
+}
+
+/**
+ * Formats a string and prints it to the specified file stream using ANSI
+ * escape sequences to specify text formatting.
+ *
+ * **Example**:
+ *
+ *     fmt::print(fmt::emphasis::bold | fg(fmt::color::red),
+ *                "Elapsed time: {0:.2f} seconds", 1.23);
+ */
+template <typename... T>
+void print(FILE* f, const text_style& ts, format_string<T...> fmt,
+           T&&... args) {
+  vprint(f, ts, fmt.str, vargs<T...>{{args...}});
+}
+
+/**
+ * Formats a string and prints it to stdout using ANSI escape sequences to
+ * specify text formatting.
+ *
+ * **Example**:
+ *
+ *     fmt::print(fmt::emphasis::bold | fg(fmt::color::red),
+ *                "Elapsed time: {0:.2f} seconds", 1.23);
+ */
+template <typename... T>
+void print(const text_style& ts, format_string<T...> fmt, T&&... args) {
+  return print(stdout, ts, fmt, std::forward<T>(args)...);
+}
+
+inline auto vformat(const text_style& ts, string_view fmt, format_args args)
+    -> std::string {
+  auto buf = memory_buffer();
+  detail::vformat_to(buf, ts, fmt, args);
+  return fmt::to_string(buf);
+}
+
+/**
+ * Formats arguments and returns the result as a string using ANSI escape
+ * sequences to specify text formatting.
+ *
+ * **Example**:
+ *
+ * ```
+ * #include <fmt/color.h>
+ * std::string message = fmt::format(fmt::emphasis::bold | fg(fmt::color::red),
+ *                                   "The answer is {}", 42);
+ * ```
+ */
+template <typename... T>
+inline auto format(const text_style& ts, format_string<T...> fmt, T&&... args)
+    -> std::string {
+  return fmt::vformat(ts, fmt.str, vargs<T...>{{args...}});
+}
+
+/// Formats a string with the given text_style and writes the output to `out`.
+template <typename OutputIt,
+          FMT_ENABLE_IF(detail::is_output_iterator<OutputIt, char>::value)>
+auto vformat_to(OutputIt out, const text_style& ts, string_view fmt,
+                format_args args) -> OutputIt {
+  auto&& buf = detail::get_buffer<char>(out);
+  detail::vformat_to(buf, ts, fmt, args);
+  return detail::get_iterator(buf, out);
+}
+
+/**
+ * Formats arguments with the given text style, writes the result to the output
+ * iterator `out` and returns the iterator past the end of the output range.
+ *
+ * **Example**:
+ *
+ *     std::vector<char> out;
+ *     fmt::format_to(std::back_inserter(out),
+ *                    fmt::emphasis::bold | fg(fmt::color::red), "{}", 42);
+ */
+template <typename OutputIt, typename... T,
+          FMT_ENABLE_IF(detail::is_output_iterator<OutputIt, char>::value)>
+inline auto format_to(OutputIt out, const text_style& ts,
+                      format_string<T...> fmt, T&&... args) -> OutputIt {
+  return vformat_to(out, ts, fmt.str, vargs<T...>{{args...}});
+}
+
+template <typename T, typename Char>
+struct formatter<detail::styled_arg<T>, Char> : formatter<T, Char> {
+  template <typename FormatContext>
+  auto format(const detail::styled_arg<T>& arg, FormatContext& ctx) const
+      -> decltype(ctx.out()) {
+    const auto& ts = arg.style;
+    auto out = ctx.out();
+
+    bool has_style = false;
+    if (ts.has_emphasis()) {
+      has_style = true;
+      auto emphasis = detail::make_emphasis<Char>(ts.get_emphasis());
+      out = detail::copy<Char>(emphasis.begin(), emphasis.end(), out);
+    }
+    if (ts.has_foreground()) {
+      has_style = true;
+      auto foreground =
+          detail::make_foreground_color<Char>(ts.get_foreground());
+      out = detail::copy<Char>(foreground.begin(), foreground.end(), out);
+    }
+    if (ts.has_background()) {
+      has_style = true;
+      auto background =
+          detail::make_background_color<Char>(ts.get_background());
+      out = detail::copy<Char>(background.begin(), background.end(), out);
+    }
+    out = formatter<T, Char>::format(arg.value, ctx);
+    if (has_style) {
+      auto reset_color = string_view("\x1b[0m");
+      out = detail::copy<Char>(reset_color.begin(), reset_color.end(), out);
+    }
+    return out;
+  }
+};
+
+/**
+ * Returns an argument that will be formatted using ANSI escape sequences,
+ * to be used in a formatting function.
+ *
+ * **Example**:
+ *
+ *     fmt::print("Elapsed time: {0:.2f} seconds",
+ *                fmt::styled(1.23, fmt::fg(fmt::color::green) |
+ *                                  fmt::bg(fmt::color::blue)));
+ */
+template <typename T>
+FMT_CONSTEXPR auto styled(const T& value, text_style ts)
+    -> detail::styled_arg<remove_cvref_t<T>> {
+  return detail::styled_arg<remove_cvref_t<T>>{value, ts};
+}
+
+FMT_END_EXPORT
+FMT_END_NAMESPACE
+
+#endif  // FMT_COLOR_H_

spdlog/fmt/bundled/compile.h

@@ -0,0 +1,551 @@
+// Formatting library for C++ - experimental format string compilation
+//
+// Copyright (c) 2012 - present, Victor Zverovich and fmt contributors
+// All rights reserved.
+//
+// For the license information refer to format.h.
+
+#ifndef FMT_COMPILE_H_
+#define FMT_COMPILE_H_
+
+#ifndef FMT_MODULE
+#  include <iterator>  // std::back_inserter
+#endif
+
+#include "format.h"
+
+FMT_BEGIN_NAMESPACE
+
+// A compile-time string which is compiled into fast formatting code.
+FMT_EXPORT class compiled_string {};
+
+namespace detail {
+
+template <typename S>
+struct is_compiled_string : std::is_base_of<compiled_string, S> {};
+
+/**
+ * Converts a string literal `s` into a format string that will be parsed at
+ * compile time and converted into efficient formatting code. Requires C++17
+ * `constexpr if` compiler support.
+ *
+ * **Example**:
+ *
+ *     // Converts 42 into std::string using the most efficient method and no
+ *     // runtime format string processing.
+ *     std::string s = fmt::format(FMT_COMPILE("{}"), 42);
+ */
+#if defined(__cpp_if_constexpr) && defined(__cpp_return_type_deduction)
+#  define FMT_COMPILE(s) FMT_STRING_IMPL(s, fmt::compiled_string)
+#else
+#  define FMT_COMPILE(s) FMT_STRING(s)
+#endif
+
+#if FMT_USE_NONTYPE_TEMPLATE_ARGS
+template <typename Char, size_t N, fmt::detail::fixed_string<Char, N> Str>
+struct udl_compiled_string : compiled_string {
+  using char_type = Char;
+  constexpr explicit operator basic_string_view<char_type>() const {
+    return {Str.data, N - 1};
+  }
+};
+#endif
+
+template <typename T, typename... Tail>
+auto first(const T& value, const Tail&...) -> const T& {
+  return value;
+}
+
+#if defined(__cpp_if_constexpr) && defined(__cpp_return_type_deduction)
+template <typename... Args> struct type_list {};
+
+// Returns a reference to the argument at index N from [first, rest...].
+template <int N, typename T, typename... Args>
+constexpr const auto& get([[maybe_unused]] const T& first,
+                          [[maybe_unused]] const Args&... rest) {
+  static_assert(N < 1 + sizeof...(Args), "index is out of bounds");
+  if constexpr (N == 0)
+    return first;
+  else
+    return detail::get<N - 1>(rest...);
+}
+
+#  if FMT_USE_NONTYPE_TEMPLATE_ARGS
+template <int N, typename T, typename... Args, typename Char>
+constexpr auto get_arg_index_by_name(basic_string_view<Char> name) -> int {
+  if constexpr (is_static_named_arg<T>()) {
+    if (name == T::name) return N;
+  }
+  if constexpr (sizeof...(Args) > 0)
+    return get_arg_index_by_name<N + 1, Args...>(name);
+  (void)name;  // Workaround an MSVC bug about "unused" parameter.
+  return -1;
+}
+#  endif
+
+template <typename... Args, typename Char>
+FMT_CONSTEXPR auto get_arg_index_by_name(basic_string_view<Char> name) -> int {
+#  if FMT_USE_NONTYPE_TEMPLATE_ARGS
+  if constexpr (sizeof...(Args) > 0)
+    return get_arg_index_by_name<0, Args...>(name);
+#  endif
+  (void)name;
+  return -1;
+}
+
+template <typename Char, typename... Args>
+constexpr int get_arg_index_by_name(basic_string_view<Char> name,
+                                    type_list<Args...>) {
+  return get_arg_index_by_name<Args...>(name);
+}
+
+template <int N, typename> struct get_type_impl;
+
+template <int N, typename... Args> struct get_type_impl<N, type_list<Args...>> {
+  using type =
+      remove_cvref_t<decltype(detail::get<N>(std::declval<Args>()...))>;
+};
+
+template <int N, typename T>
+using get_type = typename get_type_impl<N, T>::type;
+
+template <typename T> struct is_compiled_format : std::false_type {};
+
+template <typename Char> struct text {
+  basic_string_view<Char> data;
+  using char_type = Char;
+
+  template <typename OutputIt, typename... Args>
+  constexpr OutputIt format(OutputIt out, const Args&...) const {
+    return write<Char>(out, data);
+  }
+};
+
+template <typename Char>
+struct is_compiled_format<text<Char>> : std::true_type {};
+
+template <typename Char>
+constexpr text<Char> make_text(basic_string_view<Char> s, size_t pos,
+                               size_t size) {
+  return {{&s[pos], size}};
+}
+
+template <typename Char> struct code_unit {
+  Char value;
+  using char_type = Char;
+
+  template <typename OutputIt, typename... Args>
+  constexpr OutputIt format(OutputIt out, const Args&...) const {
+    *out++ = value;
+    return out;
+  }
+};
+
+// This ensures that the argument type is convertible to `const T&`.
+template <typename T, int N, typename... Args>
+constexpr const T& get_arg_checked(const Args&... args) {
+  const auto& arg = detail::get<N>(args...);
+  if constexpr (detail::is_named_arg<remove_cvref_t<decltype(arg)>>()) {
+    return arg.value;
+  } else {
+    return arg;
+  }
+}
+
+template <typename Char>
+struct is_compiled_format<code_unit<Char>> : std::true_type {};
+
+// A replacement field that refers to argument N.
+template <typename Char, typename T, int N> struct field {
+  using char_type = Char;
+
+  template <typename OutputIt, typename... Args>
+  constexpr OutputIt format(OutputIt out, const Args&... args) const {
+    const T& arg = get_arg_checked<T, N>(args...);
+    if constexpr (std::is_convertible<T, basic_string_view<Char>>::value) {
+      auto s = basic_string_view<Char>(arg);
+      return copy<Char>(s.begin(), s.end(), out);
+    } else {
+      return write<Char>(out, arg);
+    }
+  }
+};
+
+template <typename Char, typename T, int N>
+struct is_compiled_format<field<Char, T, N>> : std::true_type {};
+
+// A replacement field that refers to argument with name.
+template <typename Char> struct runtime_named_field {
+  using char_type = Char;
+  basic_string_view<Char> name;
+
+  template <typename OutputIt, typename T>
+  constexpr static bool try_format_argument(
+      OutputIt& out,
+      // [[maybe_unused]] due to unused-but-set-parameter warning in GCC 7,8,9
+      [[maybe_unused]] basic_string_view<Char> arg_name, const T& arg) {
+    if constexpr (is_named_arg<typename std::remove_cv<T>::type>::value) {
+      if (arg_name == arg.name) {
+        out = write<Char>(out, arg.value);
+        return true;
+      }
+    }
+    return false;
+  }
+
+  template <typename OutputIt, typename... Args>
+  constexpr OutputIt format(OutputIt out, const Args&... args) const {
+    bool found = (try_format_argument(out, name, args) || ...);
+    if (!found) {
+      FMT_THROW(format_error("argument with specified name is not found"));
+    }
+    return out;
+  }
+};
+
+template <typename Char>
+struct is_compiled_format<runtime_named_field<Char>> : std::true_type {};
+
+// A replacement field that refers to argument N and has format specifiers.
+template <typename Char, typename T, int N> struct spec_field {
+  using char_type = Char;
+  formatter<T, Char> fmt;
+
+  template <typename OutputIt, typename... Args>
+  constexpr FMT_INLINE OutputIt format(OutputIt out,
+                                       const Args&... args) const {
+    const auto& vargs =
+        fmt::make_format_args<basic_format_context<OutputIt, Char>>(args...);
+    basic_format_context<OutputIt, Char> ctx(out, vargs);
+    return fmt.format(get_arg_checked<T, N>(args...), ctx);
+  }
+};
+
+template <typename Char, typename T, int N>
+struct is_compiled_format<spec_field<Char, T, N>> : std::true_type {};
+
+template <typename L, typename R> struct concat {
+  L lhs;
+  R rhs;
+  using char_type = typename L::char_type;
+
+  template <typename OutputIt, typename... Args>
+  constexpr OutputIt format(OutputIt out, const Args&... args) const {
+    out = lhs.format(out, args...);
+    return rhs.format(out, args...);
+  }
+};
+
+template <typename L, typename R>
+struct is_compiled_format<concat<L, R>> : std::true_type {};
+
+template <typename L, typename R>
+constexpr concat<L, R> make_concat(L lhs, R rhs) {
+  return {lhs, rhs};
+}
+
+struct unknown_format {};
+
+template <typename Char>
+constexpr size_t parse_text(basic_string_view<Char> str, size_t pos) {
+  for (size_t size = str.size(); pos != size; ++pos) {
+    if (str[pos] == '{' || str[pos] == '}') break;
+  }
+  return pos;
+}
+
+template <typename Args, size_t POS, int ID, typename S>
+constexpr auto compile_format_string(S fmt);
+
+template <typename Args, size_t POS, int ID, typename T, typename S>
+constexpr auto parse_tail(T head, S fmt) {
+  if constexpr (POS != basic_string_view<typename S::char_type>(fmt).size()) {
+    constexpr auto tail = compile_format_string<Args, POS, ID>(fmt);
+    if constexpr (std::is_same<remove_cvref_t<decltype(tail)>,
+                               unknown_format>())
+      return tail;
+    else
+      return make_concat(head, tail);
+  } else {
+    return head;
+  }
+}
+
+template <typename T, typename Char> struct parse_specs_result {
+  formatter<T, Char> fmt;
+  size_t end;
+  int next_arg_id;
+};
+
+enum { manual_indexing_id = -1 };
+
+template <typename T, typename Char>
+constexpr parse_specs_result<T, Char> parse_specs(basic_string_view<Char> str,
+                                                  size_t pos, int next_arg_id) {
+  str.remove_prefix(pos);
+  auto ctx =
+      compile_parse_context<Char>(str, max_value<int>(), nullptr, next_arg_id);
+  auto f = formatter<T, Char>();
+  auto end = f.parse(ctx);
+  return {f, pos + fmt::detail::to_unsigned(end - str.data()),
+          next_arg_id == 0 ? manual_indexing_id : ctx.next_arg_id()};
+}
+
+template <typename Char> struct arg_id_handler {
+  arg_id_kind kind;
+  arg_ref<Char> arg_id;
+
+  constexpr int on_auto() {
+    FMT_ASSERT(false, "handler cannot be used with automatic indexing");
+    return 0;
+  }
+  constexpr int on_index(int id) {
+    kind = arg_id_kind::index;
+    arg_id = arg_ref<Char>(id);
+    return 0;
+  }
+  constexpr int on_name(basic_string_view<Char> id) {
+    kind = arg_id_kind::name;
+    arg_id = arg_ref<Char>(id);
+    return 0;
+  }
+};
+
+template <typename Char> struct parse_arg_id_result {
+  arg_id_kind kind;
+  arg_ref<Char> arg_id;
+  const Char* arg_id_end;
+};
+
+template <int ID, typename Char>
+constexpr auto parse_arg_id(const Char* begin, const Char* end) {
+  auto handler = arg_id_handler<Char>{arg_id_kind::none, arg_ref<Char>{}};
+  auto arg_id_end = parse_arg_id(begin, end, handler);
+  return parse_arg_id_result<Char>{handler.kind, handler.arg_id, arg_id_end};
+}
+
+template <typename T, typename Enable = void> struct field_type {
+  using type = remove_cvref_t<T>;
+};
+
+template <typename T>
+struct field_type<T, enable_if_t<detail::is_named_arg<T>::value>> {
+  using type = remove_cvref_t<decltype(T::value)>;
+};
+
+template <typename T, typename Args, size_t END_POS, int ARG_INDEX, int NEXT_ID,
+          typename S>
+constexpr auto parse_replacement_field_then_tail(S fmt) {
+  using char_type = typename S::char_type;
+  constexpr auto str = basic_string_view<char_type>(fmt);
+  constexpr char_type c = END_POS != str.size() ? str[END_POS] : char_type();
+  if constexpr (c == '}') {
+    return parse_tail<Args, END_POS + 1, NEXT_ID>(
+        field<char_type, typename field_type<T>::type, ARG_INDEX>(), fmt);
+  } else if constexpr (c != ':') {
+    FMT_THROW(format_error("expected ':'"));
+  } else {
+    constexpr auto result = parse_specs<typename field_type<T>::type>(
+        str, END_POS + 1, NEXT_ID == manual_indexing_id ? 0 : NEXT_ID);
+    if constexpr (result.end >= str.size() || str[result.end] != '}') {
+      FMT_THROW(format_error("expected '}'"));
+      return 0;
+    } else {
+      return parse_tail<Args, result.end + 1, result.next_arg_id>(
+          spec_field<char_type, typename field_type<T>::type, ARG_INDEX>{
+              result.fmt},
+          fmt);
+    }
+  }
+}
+
+// Compiles a non-empty format string and returns the compiled representation
+// or unknown_format() on unrecognized input.
+template <typename Args, size_t POS, int ID, typename S>
+constexpr auto compile_format_string(S fmt) {
+  using char_type = typename S::char_type;
+  constexpr auto str = basic_string_view<char_type>(fmt);
+  if constexpr (str[POS] == '{') {
+    if constexpr (POS + 1 == str.size())
+      FMT_THROW(format_error("unmatched '{' in format string"));
+    if constexpr (str[POS + 1] == '{') {
+      return parse_tail<Args, POS + 2, ID>(make_text(str, POS, 1), fmt);
+    } else if constexpr (str[POS + 1] == '}' || str[POS + 1] == ':') {
+      static_assert(ID != manual_indexing_id,
+                    "cannot switch from manual to automatic argument indexing");
+      constexpr auto next_id =
+          ID != manual_indexing_id ? ID + 1 : manual_indexing_id;
+      return parse_replacement_field_then_tail<get_type<ID, Args>, Args,
+                                               POS + 1, ID, next_id>(fmt);
+    } else {
+      constexpr auto arg_id_result =
+          parse_arg_id<ID>(str.data() + POS + 1, str.data() + str.size());
+      constexpr auto arg_id_end_pos = arg_id_result.arg_id_end - str.data();
+      constexpr char_type c =
+          arg_id_end_pos != str.size() ? str[arg_id_end_pos] : char_type();
+      static_assert(c == '}' || c == ':', "missing '}' in format string");
+      if constexpr (arg_id_result.kind == arg_id_kind::index) {
+        static_assert(
+            ID == manual_indexing_id || ID == 0,
+            "cannot switch from automatic to manual argument indexing");
+        constexpr auto arg_index = arg_id_result.arg_id.index;
+        return parse_replacement_field_then_tail<get_type<arg_index, Args>,
+                                                 Args, arg_id_end_pos,
+                                                 arg_index, manual_indexing_id>(
+            fmt);
+      } else if constexpr (arg_id_result.kind == arg_id_kind::name) {
+        constexpr auto arg_index =
+            get_arg_index_by_name(arg_id_result.arg_id.name, Args{});
+        if constexpr (arg_index >= 0) {
+          constexpr auto next_id =
+              ID != manual_indexing_id ? ID + 1 : manual_indexing_id;
+          return parse_replacement_field_then_tail<
+              decltype(get_type<arg_index, Args>::value), Args, arg_id_end_pos,
+              arg_index, next_id>(fmt);
+        } else if constexpr (c == '}') {
+          return parse_tail<Args, arg_id_end_pos + 1, ID>(
+              runtime_named_field<char_type>{arg_id_result.arg_id.name}, fmt);
+        } else if constexpr (c == ':') {
+          return unknown_format();  // no type info for specs parsing
+        }
+      }
+    }
+  } else if constexpr (str[POS] == '}') {
+    if constexpr (POS + 1 == str.size())
+      FMT_THROW(format_error("unmatched '}' in format string"));
+    return parse_tail<Args, POS + 2, ID>(make_text(str, POS, 1), fmt);
+  } else {
+    constexpr auto end = parse_text(str, POS + 1);
+    if constexpr (end - POS > 1) {
+      return parse_tail<Args, end, ID>(make_text(str, POS, end - POS), fmt);
+    } else {
+      return parse_tail<Args, end, ID>(code_unit<char_type>{str[POS]}, fmt);
+    }
+  }
+}
+
+template <typename... Args, typename S,
+          FMT_ENABLE_IF(detail::is_compiled_string<S>::value)>
+constexpr auto compile(S fmt) {
+  constexpr auto str = basic_string_view<typename S::char_type>(fmt);
+  if constexpr (str.size() == 0) {
+    return detail::make_text(str, 0, 0);
+  } else {
+    constexpr auto result =
+        detail::compile_format_string<detail::type_list<Args...>, 0, 0>(fmt);
+    return result;
+  }
+}
+#endif  // defined(__cpp_if_constexpr) && defined(__cpp_return_type_deduction)
+}  // namespace detail
+
+FMT_BEGIN_EXPORT
+
+#if defined(__cpp_if_constexpr) && defined(__cpp_return_type_deduction)
+
+template <typename CompiledFormat, typename... Args,
+          typename Char = typename CompiledFormat::char_type,
+          FMT_ENABLE_IF(detail::is_compiled_format<CompiledFormat>::value)>
+FMT_INLINE std::basic_string<Char> format(const CompiledFormat& cf,
+                                          const Args&... args) {
+  auto s = std::basic_string<Char>();
+  cf.format(std::back_inserter(s), args...);
+  return s;
+}
+
+template <typename OutputIt, typename CompiledFormat, typename... Args,
+          FMT_ENABLE_IF(detail::is_compiled_format<CompiledFormat>::value)>
+constexpr FMT_INLINE OutputIt format_to(OutputIt out, const CompiledFormat& cf,
+                                        const Args&... args) {
+  return cf.format(out, args...);
+}
+
+template <typename S, typename... Args,
+          FMT_ENABLE_IF(detail::is_compiled_string<S>::value)>
+FMT_INLINE std::basic_string<typename S::char_type> format(const S&,
+                                                           Args&&... args) {
+  if constexpr (std::is_same<typename S::char_type, char>::value) {
+    constexpr auto str = basic_string_view<typename S::char_type>(S());
+    if constexpr (str.size() == 2 && str[0] == '{' && str[1] == '}') {
+      const auto& first = detail::first(args...);
+      if constexpr (detail::is_named_arg<
+                        remove_cvref_t<decltype(first)>>::value) {
+        return fmt::to_string(first.value);
+      } else {
+        return fmt::to_string(first);
+      }
+    }
+  }
+  constexpr auto compiled = detail::compile<Args...>(S());
+  if constexpr (std::is_same<remove_cvref_t<decltype(compiled)>,
+                             detail::unknown_format>()) {
+    return fmt::format(
+        static_cast<basic_string_view<typename S::char_type>>(S()),
+        std::forward<Args>(args)...);
+  } else {
+    return fmt::format(compiled, std::forward<Args>(args)...);
+  }
+}
+
+template <typename OutputIt, typename S, typename... Args,
+          FMT_ENABLE_IF(detail::is_compiled_string<S>::value)>
+FMT_CONSTEXPR OutputIt format_to(OutputIt out, const S&, Args&&... args) {
+  constexpr auto compiled = detail::compile<Args...>(S());
+  if constexpr (std::is_same<remove_cvref_t<decltype(compiled)>,
+                             detail::unknown_format>()) {
+    return fmt::format_to(
+        out, static_cast<basic_string_view<typename S::char_type>>(S()),
+        std::forward<Args>(args)...);
+  } else {
+    return fmt::format_to(out, compiled, std::forward<Args>(args)...);
+  }
+}
+#endif
+
+template <typename OutputIt, typename S, typename... Args,
+          FMT_ENABLE_IF(detail::is_compiled_string<S>::value)>
+auto format_to_n(OutputIt out, size_t n, const S& fmt, Args&&... args)
+    -> format_to_n_result<OutputIt> {
+  using traits = detail::fixed_buffer_traits;
+  auto buf = detail::iterator_buffer<OutputIt, char, traits>(out, n);
+  fmt::format_to(std::back_inserter(buf), fmt, std::forward<Args>(args)...);
+  return {buf.out(), buf.count()};
+}
+
+template <typename S, typename... Args,
+          FMT_ENABLE_IF(detail::is_compiled_string<S>::value)>
+FMT_CONSTEXPR20 auto formatted_size(const S& fmt, const Args&... args)
+    -> size_t {
+  auto buf = detail::counting_buffer<>();
+  fmt::format_to(appender(buf), fmt, args...);
+  return buf.count();
+}
+
+template <typename S, typename... Args,
+          FMT_ENABLE_IF(detail::is_compiled_string<S>::value)>
+void print(std::FILE* f, const S& fmt, const Args&... args) {
+  auto buf = memory_buffer();
+  fmt::format_to(appender(buf), fmt, args...);
+  detail::print(f, {buf.data(), buf.size()});
+}
+
+template <typename S, typename... Args,
+          FMT_ENABLE_IF(detail::is_compiled_string<S>::value)>
+void print(const S& fmt, const Args&... args) {
+  print(stdout, fmt, args...);
+}
+
+#if FMT_USE_NONTYPE_TEMPLATE_ARGS
+inline namespace literals {
+template <detail::fixed_string Str> constexpr auto operator""_cf() {
+  using char_t = remove_cvref_t<decltype(Str.data[0])>;
+  return detail::udl_compiled_string<char_t, sizeof(Str.data) / sizeof(char_t),
+                                     Str>();
+}
+}  // namespace literals
+#endif
+
+FMT_END_EXPORT
+FMT_END_NAMESPACE
+
+#endif  // FMT_COMPILE_H_

spdlog/fmt/bundled/core.h

@@ -0,0 +1,5 @@
+// This file is only provided for compatibility and may be removed in future
+// versions. Use fmt/base.h if you don't need fmt::format and fmt/format.h
+// otherwise.
+
+#include "format.h"

spdlog/fmt/bundled/fmt.license.rst

@@ -0,0 +1,27 @@
+Copyright (c) 2012 - present, Victor Zverovich
+
+Permission is hereby granted, free of charge, to any person obtaining
+a copy of this software and associated documentation files (the
+"Software"), to deal in the Software without restriction, including
+without limitation the rights to use, copy, modify, merge, publish,
+distribute, sublicense, and/or sell copies of the Software, and to
+permit persons to whom the Software is furnished to do so, subject to
+the following conditions:
+
+The above copyright notice and this permission notice shall be
+included in all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
+LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
+OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
+WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+
+--- Optional exception to the license ---
+
+As an exception, if, as a result of your compiling your source code, portions
+of this Software are embedded into a machine-executable object form of such
+source code, you may redistribute such embedded portions in such object form
+without including the above copyright and permission notices.

spdlog/fmt/bundled/os.h

@@ -0,0 +1,427 @@
+// Formatting library for C++ - optional OS-specific functionality
+//
+// Copyright (c) 2012 - present, Victor Zverovich
+// All rights reserved.
+//
+// For the license information refer to format.h.
+
+#ifndef FMT_OS_H_
+#define FMT_OS_H_
+
+#include "format.h"
+
+#ifndef FMT_MODULE
+#  include <cerrno>
+#  include <cstddef>
+#  include <cstdio>
+#  include <system_error>  // std::system_error
+
+#  if FMT_HAS_INCLUDE(<xlocale.h>)
+#    include <xlocale.h>  // LC_NUMERIC_MASK on macOS
+#  endif
+#endif  // FMT_MODULE
+
+#ifndef FMT_USE_FCNTL
+// UWP doesn't provide _pipe.
+#  if FMT_HAS_INCLUDE("winapifamily.h")
+#    include <winapifamily.h>
+#  endif
+#  if (FMT_HAS_INCLUDE(<fcntl.h>) || defined(__APPLE__) || \
+       defined(__linux__)) &&                              \
+      (!defined(WINAPI_FAMILY) ||                          \
+       (WINAPI_FAMILY == WINAPI_FAMILY_DESKTOP_APP))
+#    include <fcntl.h>  // for O_RDONLY
+#    define FMT_USE_FCNTL 1
+#  else
+#    define FMT_USE_FCNTL 0
+#  endif
+#endif
+
+#ifndef FMT_POSIX
+#  if defined(_WIN32) && !defined(__MINGW32__)
+// Fix warnings about deprecated symbols.
+#    define FMT_POSIX(call) _##call
+#  else
+#    define FMT_POSIX(call) call
+#  endif
+#endif
+
+// Calls to system functions are wrapped in FMT_SYSTEM for testability.
+#ifdef FMT_SYSTEM
+#  define FMT_HAS_SYSTEM
+#  define FMT_POSIX_CALL(call) FMT_SYSTEM(call)
+#else
+#  define FMT_SYSTEM(call) ::call
+#  ifdef _WIN32
+// Fix warnings about deprecated symbols.
+#    define FMT_POSIX_CALL(call) ::_##call
+#  else
+#    define FMT_POSIX_CALL(call) ::call
+#  endif
+#endif
+
+// Retries the expression while it evaluates to error_result and errno
+// equals to EINTR.
+#ifndef _WIN32
+#  define FMT_RETRY_VAL(result, expression, error_result) \
+    do {                                                  \
+      (result) = (expression);                            \
+    } while ((result) == (error_result) && errno == EINTR)
+#else
+#  define FMT_RETRY_VAL(result, expression, error_result) result = (expression)
+#endif
+
+#define FMT_RETRY(result, expression) FMT_RETRY_VAL(result, expression, -1)
+
+FMT_BEGIN_NAMESPACE
+FMT_BEGIN_EXPORT
+
+/**
+ * A reference to a null-terminated string. It can be constructed from a C
+ * string or `std::string`.
+ *
+ * You can use one of the following type aliases for common character types:
+ *
+ * +---------------+-----------------------------+
+ * | Type          | Definition                  |
+ * +===============+=============================+
+ * | cstring_view  | basic_cstring_view<char>    |
+ * +---------------+-----------------------------+
+ * | wcstring_view | basic_cstring_view<wchar_t> |
+ * +---------------+-----------------------------+
+ *
+ * This class is most useful as a parameter type for functions that wrap C APIs.
+ */
+template <typename Char> class basic_cstring_view {
+ private:
+  const Char* data_;
+
+ public:
+  /// Constructs a string reference object from a C string.
+  basic_cstring_view(const Char* s) : data_(s) {}
+
+  /// Constructs a string reference from an `std::string` object.
+  basic_cstring_view(const std::basic_string<Char>& s) : data_(s.c_str()) {}
+
+  /// Returns the pointer to a C string.
+  auto c_str() const -> const Char* { return data_; }
+};
+
+using cstring_view = basic_cstring_view<char>;
+using wcstring_view = basic_cstring_view<wchar_t>;
+
+#ifdef _WIN32
+FMT_API const std::error_category& system_category() noexcept;
+
+namespace detail {
+FMT_API void format_windows_error(buffer<char>& out, int error_code,
+                                  const char* message) noexcept;
+}
+
+FMT_API std::system_error vwindows_error(int error_code, string_view fmt,
+                                         format_args args);
+
+/**
+ * Constructs a `std::system_error` object with the description of the form
+ *
+ *     <message>: <system-message>
+ *
+ * where `<message>` is the formatted message and `<system-message>` is the
+ * system message corresponding to the error code.
+ * `error_code` is a Windows error code as given by `GetLastError`.
+ * If `error_code` is not a valid error code such as -1, the system message
+ * will look like "error -1".
+ *
+ * **Example**:
+ *
+ *     // This throws a system_error with the description
+ *     //   cannot open file 'madeup': The system cannot find the file
+ * specified.
+ *     // or similar (system message may vary).
+ *     const char *filename = "madeup";
+ *     LPOFSTRUCT of = LPOFSTRUCT();
+ *     HFILE file = OpenFile(filename, &of, OF_READ);
+ *     if (file == HFILE_ERROR) {
+ *       throw fmt::windows_error(GetLastError(),
+ *                                "cannot open file '{}'", filename);
+ *     }
+ */
+template <typename... T>
+auto windows_error(int error_code, string_view message, const T&... args)
+    -> std::system_error {
+  return vwindows_error(error_code, message, vargs<T...>{{args...}});
+}
+
+// Reports a Windows error without throwing an exception.
+// Can be used to report errors from destructors.
+FMT_API void report_windows_error(int error_code, const char* message) noexcept;
+#else
+inline auto system_category() noexcept -> const std::error_category& {
+  return std::system_category();
+}
+#endif  // _WIN32
+
+// std::system is not available on some platforms such as iOS (#2248).
+#ifdef __OSX__
+template <typename S, typename... Args, typename Char = char_t<S>>
+void say(const S& fmt, Args&&... args) {
+  std::system(format("say \"{}\"", format(fmt, args...)).c_str());
+}
+#endif
+
+// A buffered file.
+class buffered_file {
+ private:
+  FILE* file_;
+
+  friend class file;
+
+  inline explicit buffered_file(FILE* f) : file_(f) {}
+
+ public:
+  buffered_file(const buffered_file&) = delete;
+  void operator=(const buffered_file&) = delete;
+
+  // Constructs a buffered_file object which doesn't represent any file.
+  inline buffered_file() noexcept : file_(nullptr) {}
+
+  // Destroys the object closing the file it represents if any.
+  FMT_API ~buffered_file() noexcept;
+
+ public:
+  inline buffered_file(buffered_file&& other) noexcept : file_(other.file_) {
+    other.file_ = nullptr;
+  }
+
+  inline auto operator=(buffered_file&& other) -> buffered_file& {
+    close();
+    file_ = other.file_;
+    other.file_ = nullptr;
+    return *this;
+  }
+
+  // Opens a file.
+  FMT_API buffered_file(cstring_view filename, cstring_view mode);
+
+  // Closes the file.
+  FMT_API void close();
+
+  // Returns the pointer to a FILE object representing this file.
+  inline auto get() const noexcept -> FILE* { return file_; }
+
+  FMT_API auto descriptor() const -> int;
+
+  template <typename... T>
+  inline void print(string_view fmt, const T&... args) {
+    fmt::vargs<T...> vargs = {{args...}};
+    detail::is_locking<T...>() ? fmt::vprint_buffered(file_, fmt, vargs)
+                               : fmt::vprint(file_, fmt, vargs);
+  }
+};
+
+#if FMT_USE_FCNTL
+
+// A file. Closed file is represented by a file object with descriptor -1.
+// Methods that are not declared with noexcept may throw
+// fmt::system_error in case of failure. Note that some errors such as
+// closing the file multiple times will cause a crash on Windows rather
+// than an exception. You can get standard behavior by overriding the
+// invalid parameter handler with _set_invalid_parameter_handler.
+class FMT_API file {
+ private:
+  int fd_;  // File descriptor.
+
+  // Constructs a file object with a given descriptor.
+  explicit file(int fd) : fd_(fd) {}
+
+  friend struct pipe;
+
+ public:
+  // Possible values for the oflag argument to the constructor.
+  enum {
+    RDONLY = FMT_POSIX(O_RDONLY),  // Open for reading only.
+    WRONLY = FMT_POSIX(O_WRONLY),  // Open for writing only.
+    RDWR = FMT_POSIX(O_RDWR),      // Open for reading and writing.
+    CREATE = FMT_POSIX(O_CREAT),   // Create if the file doesn't exist.
+    APPEND = FMT_POSIX(O_APPEND),  // Open in append mode.
+    TRUNC = FMT_POSIX(O_TRUNC)     // Truncate the content of the file.
+  };
+
+  // Constructs a file object which doesn't represent any file.
+  inline file() noexcept : fd_(-1) {}
+
+  // Opens a file and constructs a file object representing this file.
+  file(cstring_view path, int oflag);
+
+ public:
+  file(const file&) = delete;
+  void operator=(const file&) = delete;
+
+  inline file(file&& other) noexcept : fd_(other.fd_) { other.fd_ = -1; }
+
+  // Move assignment is not noexcept because close may throw.
+  inline auto operator=(file&& other) -> file& {
+    close();
+    fd_ = other.fd_;
+    other.fd_ = -1;
+    return *this;
+  }
+
+  // Destroys the object closing the file it represents if any.
+  ~file() noexcept;
+
+  // Returns the file descriptor.
+  inline auto descriptor() const noexcept -> int { return fd_; }
+
+  // Closes the file.
+  void close();
+
+  // Returns the file size. The size has signed type for consistency with
+  // stat::st_size.
+  auto size() const -> long long;
+
+  // Attempts to read count bytes from the file into the specified buffer.
+  auto read(void* buffer, size_t count) -> size_t;
+
+  // Attempts to write count bytes from the specified buffer to the file.
+  auto write(const void* buffer, size_t count) -> size_t;
+
+  // Duplicates a file descriptor with the dup function and returns
+  // the duplicate as a file object.
+  static auto dup(int fd) -> file;
+
+  // Makes fd be the copy of this file descriptor, closing fd first if
+  // necessary.
+  void dup2(int fd);
+
+  // Makes fd be the copy of this file descriptor, closing fd first if
+  // necessary.
+  void dup2(int fd, std::error_code& ec) noexcept;
+
+  // Creates a buffered_file object associated with this file and detaches
+  // this file object from the file.
+  auto fdopen(const char* mode) -> buffered_file;
+
+#  if defined(_WIN32) && !defined(__MINGW32__)
+  // Opens a file and constructs a file object representing this file by
+  // wcstring_view filename. Windows only.
+  static file open_windows_file(wcstring_view path, int oflag);
+#  endif
+};
+
+struct FMT_API pipe {
+  file read_end;
+  file write_end;
+
+  // Creates a pipe setting up read_end and write_end file objects for reading
+  // and writing respectively.
+  pipe();
+};
+
+// Returns the memory page size.
+auto getpagesize() -> long;
+
+namespace detail {
+
+struct buffer_size {
+  constexpr buffer_size() = default;
+  size_t value = 0;
+  FMT_CONSTEXPR auto operator=(size_t val) const -> buffer_size {
+    auto bs = buffer_size();
+    bs.value = val;
+    return bs;
+  }
+};
+
+struct ostream_params {
+  int oflag = file::WRONLY | file::CREATE | file::TRUNC;
+  size_t buffer_size = BUFSIZ > 32768 ? BUFSIZ : 32768;
+
+  constexpr ostream_params() {}
+
+  template <typename... T>
+  ostream_params(T... params, int new_oflag) : ostream_params(params...) {
+    oflag = new_oflag;
+  }
+
+  template <typename... T>
+  ostream_params(T... params, detail::buffer_size bs)
+      : ostream_params(params...) {
+    this->buffer_size = bs.value;
+  }
+
+// Intel has a bug that results in failure to deduce a constructor
+// for empty parameter packs.
+#  if defined(__INTEL_COMPILER) && __INTEL_COMPILER < 2000
+  ostream_params(int new_oflag) : oflag(new_oflag) {}
+  ostream_params(detail::buffer_size bs) : buffer_size(bs.value) {}
+#  endif
+};
+
+}  // namespace detail
+
+FMT_INLINE_VARIABLE constexpr auto buffer_size = detail::buffer_size();
+
+/// A fast buffered output stream for writing from a single thread. Writing from
+/// multiple threads without external synchronization may result in a data race.
+class FMT_API ostream : private detail::buffer<char> {
+ private:
+  file file_;
+
+  ostream(cstring_view path, const detail::ostream_params& params);
+
+  static void grow(buffer<char>& buf, size_t);
+
+ public:
+  ostream(ostream&& other) noexcept;
+  ~ostream();
+
+  operator writer() {
+    detail::buffer<char>& buf = *this;
+    return buf;
+  }
+
+  inline void flush() {
+    if (size() == 0) return;
+    file_.write(data(), size() * sizeof(data()[0]));
+    clear();
+  }
+
+  template <typename... T>
+  friend auto output_file(cstring_view path, T... params) -> ostream;
+
+  inline void close() {
+    flush();
+    file_.close();
+  }
+
+  /// Formats `args` according to specifications in `fmt` and writes the
+  /// output to the file.
+  template <typename... T> void print(format_string<T...> fmt, T&&... args) {
+    vformat_to(appender(*this), fmt.str, vargs<T...>{{args...}});
+  }
+};
+
+/**
+ * Opens a file for writing. Supported parameters passed in `params`:
+ *
+ * - `<integer>`: Flags passed to [open](
+ *   https://pubs.opengroup.org/onlinepubs/007904875/functions/open.html)
+ *   (`file::WRONLY | file::CREATE | file::TRUNC` by default)
+ * - `buffer_size=<integer>`: Output buffer size
+ *
+ * **Example**:
+ *
+ *     auto out = fmt::output_file("guide.txt");
+ *     out.print("Don't {}", "Panic");
+ */
+template <typename... T>
+inline auto output_file(cstring_view path, T... params) -> ostream {
+  return {path, detail::ostream_params(params...)};
+}
+#endif  // FMT_USE_FCNTL
+
+FMT_END_EXPORT
+FMT_END_NAMESPACE
+
+#endif  // FMT_OS_H_

spdlog/fmt/bundled/ostream.h

@@ -0,0 +1,166 @@
+// Formatting library for C++ - std::ostream support
+//
+// Copyright (c) 2012 - present, Victor Zverovich
+// All rights reserved.
+//
+// For the license information refer to format.h.
+
+#ifndef FMT_OSTREAM_H_
+#define FMT_OSTREAM_H_
+
+#ifndef FMT_MODULE
+#  include <fstream>  // std::filebuf
+#endif
+
+#ifdef _WIN32
+#  ifdef __GLIBCXX__
+#    include <ext/stdio_filebuf.h>
+#    include <ext/stdio_sync_filebuf.h>
+#  endif
+#  include <io.h>
+#endif
+
+#include "chrono.h"  // formatbuf
+
+#ifdef _MSVC_STL_UPDATE
+#  define FMT_MSVC_STL_UPDATE _MSVC_STL_UPDATE
+#elif defined(_MSC_VER) && _MSC_VER < 1912  // VS 15.5
+#  define FMT_MSVC_STL_UPDATE _MSVC_LANG
+#else
+#  define FMT_MSVC_STL_UPDATE 0
+#endif
+
+FMT_BEGIN_NAMESPACE
+namespace detail {
+
+// Generate a unique explicit instantion in every translation unit using a tag
+// type in an anonymous namespace.
+namespace {
+struct file_access_tag {};
+}  // namespace
+template <typename Tag, typename BufType, FILE* BufType::*FileMemberPtr>
+class file_access {
+  friend auto get_file(BufType& obj) -> FILE* { return obj.*FileMemberPtr; }
+};
+
+#if FMT_MSVC_STL_UPDATE
+template class file_access<file_access_tag, std::filebuf,
+                           &std::filebuf::_Myfile>;
+auto get_file(std::filebuf&) -> FILE*;
+#endif
+
+// Write the content of buf to os.
+// It is a separate function rather than a part of vprint to simplify testing.
+template <typename Char>
+void write_buffer(std::basic_ostream<Char>& os, buffer<Char>& buf) {
+  const Char* buf_data = buf.data();
+  using unsigned_streamsize = make_unsigned_t<std::streamsize>;
+  unsigned_streamsize size = buf.size();
+  unsigned_streamsize max_size = to_unsigned(max_value<std::streamsize>());
+  do {
+    unsigned_streamsize n = size <= max_size ? size : max_size;
+    os.write(buf_data, static_cast<std::streamsize>(n));
+    buf_data += n;
+    size -= n;
+  } while (size != 0);
+}
+
+template <typename T> struct streamed_view {
+  const T& value;
+};
+}  // namespace detail
+
+// Formats an object of type T that has an overloaded ostream operator<<.
+template <typename Char>
+struct basic_ostream_formatter : formatter<basic_string_view<Char>, Char> {
+  void set_debug_format() = delete;
+
+  template <typename T, typename Context>
+  auto format(const T& value, Context& ctx) const -> decltype(ctx.out()) {
+    auto buffer = basic_memory_buffer<Char>();
+    auto&& formatbuf = detail::formatbuf<std::basic_streambuf<Char>>(buffer);
+    auto&& output = std::basic_ostream<Char>(&formatbuf);
+    output.imbue(std::locale::classic());  // The default is always unlocalized.
+    output << value;
+    output.exceptions(std::ios_base::failbit | std::ios_base::badbit);
+    return formatter<basic_string_view<Char>, Char>::format(
+        {buffer.data(), buffer.size()}, ctx);
+  }
+};
+
+using ostream_formatter = basic_ostream_formatter<char>;
+
+template <typename T, typename Char>
+struct formatter<detail::streamed_view<T>, Char>
+    : basic_ostream_formatter<Char> {
+  template <typename Context>
+  auto format(detail::streamed_view<T> view, Context& ctx) const
+      -> decltype(ctx.out()) {
+    return basic_ostream_formatter<Char>::format(view.value, ctx);
+  }
+};
+
+/**
+ * Returns a view that formats `value` via an ostream `operator<<`.
+ *
+ * **Example**:
+ *
+ *     fmt::print("Current thread id: {}\n",
+ *                fmt::streamed(std::this_thread::get_id()));
+ */
+template <typename T>
+constexpr auto streamed(const T& value) -> detail::streamed_view<T> {
+  return {value};
+}
+
+inline void vprint(std::ostream& os, string_view fmt, format_args args) {
+  auto buffer = memory_buffer();
+  detail::vformat_to(buffer, fmt, args);
+  FILE* f = nullptr;
+#if FMT_MSVC_STL_UPDATE && FMT_USE_RTTI
+  if (auto* buf = dynamic_cast<std::filebuf*>(os.rdbuf()))
+    f = detail::get_file(*buf);
+#elif defined(_WIN32) && defined(__GLIBCXX__) && FMT_USE_RTTI
+  auto* rdbuf = os.rdbuf();
+  if (auto* sfbuf = dynamic_cast<__gnu_cxx::stdio_sync_filebuf<char>*>(rdbuf))
+    f = sfbuf->file();
+  else if (auto* fbuf = dynamic_cast<__gnu_cxx::stdio_filebuf<char>*>(rdbuf))
+    f = fbuf->file();
+#endif
+#ifdef _WIN32
+  if (f) {
+    int fd = _fileno(f);
+    if (_isatty(fd)) {
+      os.flush();
+      if (detail::write_console(fd, {buffer.data(), buffer.size()})) return;
+    }
+  }
+#endif
+  detail::ignore_unused(f);
+  detail::write_buffer(os, buffer);
+}
+
+/**
+ * Prints formatted data to the stream `os`.
+ *
+ * **Example**:
+ *
+ *     fmt::print(cerr, "Don't {}!", "panic");
+ */
+FMT_EXPORT template <typename... T>
+void print(std::ostream& os, format_string<T...> fmt, T&&... args) {
+  fmt::vargs<T...> vargs = {{args...}};
+  if (detail::const_check(detail::use_utf8)) return vprint(os, fmt.str, vargs);
+  auto buffer = memory_buffer();
+  detail::vformat_to(buffer, fmt.str, vargs);
+  detail::write_buffer(os, buffer);
+}
+
+FMT_EXPORT template <typename... T>
+void println(std::ostream& os, format_string<T...> fmt, T&&... args) {
+  fmt::print(os, "{}\n", fmt::format(fmt, std::forward<T>(args)...));
+}
+
+FMT_END_NAMESPACE
+
+#endif  // FMT_OSTREAM_H_

spdlog/fmt/bundled/printf.h

@@ -0,0 +1,633 @@
+// Formatting library for C++ - legacy printf implementation
+//
+// Copyright (c) 2012 - 2016, Victor Zverovich
+// All rights reserved.
+//
+// For the license information refer to format.h.
+
+#ifndef FMT_PRINTF_H_
+#define FMT_PRINTF_H_
+
+#ifndef FMT_MODULE
+#  include <algorithm>  // std::max
+#  include <limits>     // std::numeric_limits
+#endif
+
+#include "format.h"
+
+FMT_BEGIN_NAMESPACE
+FMT_BEGIN_EXPORT
+
+template <typename T> struct printf_formatter {
+  printf_formatter() = delete;
+};
+
+template <typename Char> class basic_printf_context {
+ private:
+  basic_appender<Char> out_;
+  basic_format_args<basic_printf_context> args_;
+
+  static_assert(std::is_same<Char, char>::value ||
+                    std::is_same<Char, wchar_t>::value,
+                "Unsupported code unit type.");
+
+ public:
+  using char_type = Char;
+  using parse_context_type = parse_context<Char>;
+  template <typename T> using formatter_type = printf_formatter<T>;
+  enum { builtin_types = 1 };
+
+  /// Constructs a `printf_context` object. References to the arguments are
+  /// stored in the context object so make sure they have appropriate lifetimes.
+  basic_printf_context(basic_appender<Char> out,
+                       basic_format_args<basic_printf_context> args)
+      : out_(out), args_(args) {}
+
+  auto out() -> basic_appender<Char> { return out_; }
+  void advance_to(basic_appender<Char>) {}
+
+  auto locale() -> detail::locale_ref { return {}; }
+
+  auto arg(int id) const -> basic_format_arg<basic_printf_context> {
+    return args_.get(id);
+  }
+};
+
+namespace detail {
+
+// Return the result via the out param to workaround gcc bug 77539.
+template <bool IS_CONSTEXPR, typename T, typename Ptr = const T*>
+FMT_CONSTEXPR auto find(Ptr first, Ptr last, T value, Ptr& out) -> bool {
+  for (out = first; out != last; ++out) {
+    if (*out == value) return true;
+  }
+  return false;
+}
+
+template <>
+inline auto find<false, char>(const char* first, const char* last, char value,
+                              const char*& out) -> bool {
+  out =
+      static_cast<const char*>(memchr(first, value, to_unsigned(last - first)));
+  return out != nullptr;
+}
+
+// Checks if a value fits in int - used to avoid warnings about comparing
+// signed and unsigned integers.
+template <bool IsSigned> struct int_checker {
+  template <typename T> static auto fits_in_int(T value) -> bool {
+    unsigned max = to_unsigned(max_value<int>());
+    return value <= max;
+  }
+  inline static auto fits_in_int(bool) -> bool { return true; }
+};
+
+template <> struct int_checker<true> {
+  template <typename T> static auto fits_in_int(T value) -> bool {
+    return value >= (std::numeric_limits<int>::min)() &&
+           value <= max_value<int>();
+  }
+  inline static auto fits_in_int(int) -> bool { return true; }
+};
+
+struct printf_precision_handler {
+  template <typename T, FMT_ENABLE_IF(std::is_integral<T>::value)>
+  auto operator()(T value) -> int {
+    if (!int_checker<std::numeric_limits<T>::is_signed>::fits_in_int(value))
+      report_error("number is too big");
+    return (std::max)(static_cast<int>(value), 0);
+  }
+
+  template <typename T, FMT_ENABLE_IF(!std::is_integral<T>::value)>
+  auto operator()(T) -> int {
+    report_error("precision is not integer");
+    return 0;
+  }
+};
+
+// An argument visitor that returns true iff arg is a zero integer.
+struct is_zero_int {
+  template <typename T, FMT_ENABLE_IF(std::is_integral<T>::value)>
+  auto operator()(T value) -> bool {
+    return value == 0;
+  }
+
+  template <typename T, FMT_ENABLE_IF(!std::is_integral<T>::value)>
+  auto operator()(T) -> bool {
+    return false;
+  }
+};
+
+template <typename T> struct make_unsigned_or_bool : std::make_unsigned<T> {};
+
+template <> struct make_unsigned_or_bool<bool> {
+  using type = bool;
+};
+
+template <typename T, typename Context> class arg_converter {
+ private:
+  using char_type = typename Context::char_type;
+
+  basic_format_arg<Context>& arg_;
+  char_type type_;
+
+ public:
+  arg_converter(basic_format_arg<Context>& arg, char_type type)
+      : arg_(arg), type_(type) {}
+
+  void operator()(bool value) {
+    if (type_ != 's') operator()<bool>(value);
+  }
+
+  template <typename U, FMT_ENABLE_IF(std::is_integral<U>::value)>
+  void operator()(U value) {
+    bool is_signed = type_ == 'd' || type_ == 'i';
+    using target_type = conditional_t<std::is_same<T, void>::value, U, T>;
+    if (const_check(sizeof(target_type) <= sizeof(int))) {
+      // Extra casts are used to silence warnings.
+      using unsigned_type = typename make_unsigned_or_bool<target_type>::type;
+      if (is_signed)
+        arg_ = static_cast<int>(static_cast<target_type>(value));
+      else
+        arg_ = static_cast<unsigned>(static_cast<unsigned_type>(value));
+    } else {
+      // glibc's printf doesn't sign extend arguments of smaller types:
+      //   std::printf("%lld", -42);  // prints "4294967254"
+      // but we don't have to do the same because it's a UB.
+      if (is_signed)
+        arg_ = static_cast<long long>(value);
+      else
+        arg_ = static_cast<typename make_unsigned_or_bool<U>::type>(value);
+    }
+  }
+
+  template <typename U, FMT_ENABLE_IF(!std::is_integral<U>::value)>
+  void operator()(U) {}  // No conversion needed for non-integral types.
+};
+
+// Converts an integer argument to T for printf, if T is an integral type.
+// If T is void, the argument is converted to corresponding signed or unsigned
+// type depending on the type specifier: 'd' and 'i' - signed, other -
+// unsigned).
+template <typename T, typename Context, typename Char>
+void convert_arg(basic_format_arg<Context>& arg, Char type) {
+  arg.visit(arg_converter<T, Context>(arg, type));
+}
+
+// Converts an integer argument to char for printf.
+template <typename Context> class char_converter {
+ private:
+  basic_format_arg<Context>& arg_;
+
+ public:
+  explicit char_converter(basic_format_arg<Context>& arg) : arg_(arg) {}
+
+  template <typename T, FMT_ENABLE_IF(std::is_integral<T>::value)>
+  void operator()(T value) {
+    arg_ = static_cast<typename Context::char_type>(value);
+  }
+
+  template <typename T, FMT_ENABLE_IF(!std::is_integral<T>::value)>
+  void operator()(T) {}  // No conversion needed for non-integral types.
+};
+
+// An argument visitor that return a pointer to a C string if argument is a
+// string or null otherwise.
+template <typename Char> struct get_cstring {
+  template <typename T> auto operator()(T) -> const Char* { return nullptr; }
+  auto operator()(const Char* s) -> const Char* { return s; }
+};
+
+// Checks if an argument is a valid printf width specifier and sets
+// left alignment if it is negative.
+class printf_width_handler {
+ private:
+  format_specs& specs_;
+
+ public:
+  inline explicit printf_width_handler(format_specs& specs) : specs_(specs) {}
+
+  template <typename T, FMT_ENABLE_IF(std::is_integral<T>::value)>
+  auto operator()(T value) -> unsigned {
+    auto width = static_cast<uint32_or_64_or_128_t<T>>(value);
+    if (detail::is_negative(value)) {
+      specs_.set_align(align::left);
+      width = 0 - width;
+    }
+    unsigned int_max = to_unsigned(max_value<int>());
+    if (width > int_max) report_error("number is too big");
+    return static_cast<unsigned>(width);
+  }
+
+  template <typename T, FMT_ENABLE_IF(!std::is_integral<T>::value)>
+  auto operator()(T) -> unsigned {
+    report_error("width is not integer");
+    return 0;
+  }
+};
+
+// Workaround for a bug with the XL compiler when initializing
+// printf_arg_formatter's base class.
+template <typename Char>
+auto make_arg_formatter(basic_appender<Char> iter, format_specs& s)
+    -> arg_formatter<Char> {
+  return {iter, s, locale_ref()};
+}
+
+// The `printf` argument formatter.
+template <typename Char>
+class printf_arg_formatter : public arg_formatter<Char> {
+ private:
+  using base = arg_formatter<Char>;
+  using context_type = basic_printf_context<Char>;
+
+  context_type& context_;
+
+  void write_null_pointer(bool is_string = false) {
+    auto s = this->specs;
+    s.set_type(presentation_type::none);
+    write_bytes<Char>(this->out, is_string ? "(null)" : "(nil)", s);
+  }
+
+  template <typename T> void write(T value) {
+    detail::write<Char>(this->out, value, this->specs, this->locale);
+  }
+
+ public:
+  printf_arg_formatter(basic_appender<Char> iter, format_specs& s,
+                       context_type& ctx)
+      : base(make_arg_formatter(iter, s)), context_(ctx) {}
+
+  void operator()(monostate value) { write(value); }
+
+  template <typename T, FMT_ENABLE_IF(detail::is_integral<T>::value)>
+  void operator()(T value) {
+    // MSVC2013 fails to compile separate overloads for bool and Char so use
+    // std::is_same instead.
+    if (!std::is_same<T, Char>::value) {
+      write(value);
+      return;
+    }
+    format_specs s = this->specs;
+    if (s.type() != presentation_type::none &&
+        s.type() != presentation_type::chr) {
+      return (*this)(static_cast<int>(value));
+    }
+    s.set_sign(sign::none);
+    s.clear_alt();
+    s.set_fill(' ');  // Ignore '0' flag for char types.
+    // align::numeric needs to be overwritten here since the '0' flag is
+    // ignored for non-numeric types
+    if (s.align() == align::none || s.align() == align::numeric)
+      s.set_align(align::right);
+    detail::write<Char>(this->out, static_cast<Char>(value), s);
+  }
+
+  template <typename T, FMT_ENABLE_IF(std::is_floating_point<T>::value)>
+  void operator()(T value) {
+    write(value);
+  }
+
+  void operator()(const char* value) {
+    if (value)
+      write(value);
+    else
+      write_null_pointer(this->specs.type() != presentation_type::pointer);
+  }
+
+  void operator()(const wchar_t* value) {
+    if (value)
+      write(value);
+    else
+      write_null_pointer(this->specs.type() != presentation_type::pointer);
+  }
+
+  void operator()(basic_string_view<Char> value) { write(value); }
+
+  void operator()(const void* value) {
+    if (value)
+      write(value);
+    else
+      write_null_pointer();
+  }
+
+  void operator()(typename basic_format_arg<context_type>::handle handle) {
+    auto parse_ctx = parse_context<Char>({});
+    handle.format(parse_ctx, context_);
+  }
+};
+
+template <typename Char>
+void parse_flags(format_specs& specs, const Char*& it, const Char* end) {
+  for (; it != end; ++it) {
+    switch (*it) {
+    case '-': specs.set_align(align::left); break;
+    case '+': specs.set_sign(sign::plus); break;
+    case '0': specs.set_fill('0'); break;
+    case ' ':
+      if (specs.sign() != sign::plus) specs.set_sign(sign::space);
+      break;
+    case '#': specs.set_alt(); break;
+    default:  return;
+    }
+  }
+}
+
+template <typename Char, typename GetArg>
+auto parse_header(const Char*& it, const Char* end, format_specs& specs,
+                  GetArg get_arg) -> int {
+  int arg_index = -1;
+  Char c = *it;
+  if (c >= '0' && c <= '9') {
+    // Parse an argument index (if followed by '$') or a width possibly
+    // preceded with '0' flag(s).
+    int value = parse_nonnegative_int(it, end, -1);
+    if (it != end && *it == '$') {  // value is an argument index
+      ++it;
+      arg_index = value != -1 ? value : max_value<int>();
+    } else {
+      if (c == '0') specs.set_fill('0');
+      if (value != 0) {
+        // Nonzero value means that we parsed width and don't need to
+        // parse it or flags again, so return now.
+        if (value == -1) report_error("number is too big");
+        specs.width = value;
+        return arg_index;
+      }
+    }
+  }
+  parse_flags(specs, it, end);
+  // Parse width.
+  if (it != end) {
+    if (*it >= '0' && *it <= '9') {
+      specs.width = parse_nonnegative_int(it, end, -1);
+      if (specs.width == -1) report_error("number is too big");
+    } else if (*it == '*') {
+      ++it;
+      specs.width = static_cast<int>(
+          get_arg(-1).visit(detail::printf_width_handler(specs)));
+    }
+  }
+  return arg_index;
+}
+
+inline auto parse_printf_presentation_type(char c, type t, bool& upper)
+    -> presentation_type {
+  using pt = presentation_type;
+  constexpr auto integral_set = sint_set | uint_set | bool_set | char_set;
+  switch (c) {
+  case 'd': return in(t, integral_set) ? pt::dec : pt::none;
+  case 'o': return in(t, integral_set) ? pt::oct : pt::none;
+  case 'X': upper = true; FMT_FALLTHROUGH;
+  case 'x': return in(t, integral_set) ? pt::hex : pt::none;
+  case 'E': upper = true; FMT_FALLTHROUGH;
+  case 'e': return in(t, float_set) ? pt::exp : pt::none;
+  case 'F': upper = true; FMT_FALLTHROUGH;
+  case 'f': return in(t, float_set) ? pt::fixed : pt::none;
+  case 'G': upper = true; FMT_FALLTHROUGH;
+  case 'g': return in(t, float_set) ? pt::general : pt::none;
+  case 'A': upper = true; FMT_FALLTHROUGH;
+  case 'a': return in(t, float_set) ? pt::hexfloat : pt::none;
+  case 'c': return in(t, integral_set) ? pt::chr : pt::none;
+  case 's': return in(t, string_set | cstring_set) ? pt::string : pt::none;
+  case 'p': return in(t, pointer_set | cstring_set) ? pt::pointer : pt::none;
+  default:  return pt::none;
+  }
+}
+
+template <typename Char, typename Context>
+void vprintf(buffer<Char>& buf, basic_string_view<Char> format,
+             basic_format_args<Context> args) {
+  using iterator = basic_appender<Char>;
+  auto out = iterator(buf);
+  auto context = basic_printf_context<Char>(out, args);
+  auto parse_ctx = parse_context<Char>(format);
+
+  // Returns the argument with specified index or, if arg_index is -1, the next
+  // argument.
+  auto get_arg = [&](int arg_index) {
+    if (arg_index < 0)
+      arg_index = parse_ctx.next_arg_id();
+    else
+      parse_ctx.check_arg_id(--arg_index);
+    return detail::get_arg(context, arg_index);
+  };
+
+  const Char* start = parse_ctx.begin();
+  const Char* end = parse_ctx.end();
+  auto it = start;
+  while (it != end) {
+    if (!find<false, Char>(it, end, '%', it)) {
+      it = end;  // find leaves it == nullptr if it doesn't find '%'.
+      break;
+    }
+    Char c = *it++;
+    if (it != end && *it == c) {
+      write(out, basic_string_view<Char>(start, to_unsigned(it - start)));
+      start = ++it;
+      continue;
+    }
+    write(out, basic_string_view<Char>(start, to_unsigned(it - 1 - start)));
+
+    auto specs = format_specs();
+    specs.set_align(align::right);
+
+    // Parse argument index, flags and width.
+    int arg_index = parse_header(it, end, specs, get_arg);
+    if (arg_index == 0) report_error("argument not found");
+
+    // Parse precision.
+    if (it != end && *it == '.') {
+      ++it;
+      c = it != end ? *it : 0;
+      if ('0' <= c && c <= '9') {
+        specs.precision = parse_nonnegative_int(it, end, 0);
+      } else if (c == '*') {
+        ++it;
+        specs.precision =
+            static_cast<int>(get_arg(-1).visit(printf_precision_handler()));
+      } else {
+        specs.precision = 0;
+      }
+    }
+
+    auto arg = get_arg(arg_index);
+    // For d, i, o, u, x, and X conversion specifiers, if a precision is
+    // specified, the '0' flag is ignored
+    if (specs.precision >= 0 && is_integral_type(arg.type())) {
+      // Ignore '0' for non-numeric types or if '-' present.
+      specs.set_fill(' ');
+    }
+    if (specs.precision >= 0 && arg.type() == type::cstring_type) {
+      auto str = arg.visit(get_cstring<Char>());
+      auto str_end = str + specs.precision;
+      auto nul = std::find(str, str_end, Char());
+      auto sv = basic_string_view<Char>(
+          str, to_unsigned(nul != str_end ? nul - str : specs.precision));
+      arg = sv;
+    }
+    if (specs.alt() && arg.visit(is_zero_int())) specs.clear_alt();
+    if (specs.fill_unit<Char>() == '0') {
+      if (is_arithmetic_type(arg.type()) && specs.align() != align::left) {
+        specs.set_align(align::numeric);
+      } else {
+        // Ignore '0' flag for non-numeric types or if '-' flag is also present.
+        specs.set_fill(' ');
+      }
+    }
+
+    // Parse length and convert the argument to the required type.
+    c = it != end ? *it++ : 0;
+    Char t = it != end ? *it : 0;
+    switch (c) {
+    case 'h':
+      if (t == 'h') {
+        ++it;
+        t = it != end ? *it : 0;
+        convert_arg<signed char>(arg, t);
+      } else {
+        convert_arg<short>(arg, t);
+      }
+      break;
+    case 'l':
+      if (t == 'l') {
+        ++it;
+        t = it != end ? *it : 0;
+        convert_arg<long long>(arg, t);
+      } else {
+        convert_arg<long>(arg, t);
+      }
+      break;
+    case 'j': convert_arg<intmax_t>(arg, t); break;
+    case 'z': convert_arg<size_t>(arg, t); break;
+    case 't': convert_arg<std::ptrdiff_t>(arg, t); break;
+    case 'L':
+      // printf produces garbage when 'L' is omitted for long double, no
+      // need to do the same.
+      break;
+    default: --it; convert_arg<void>(arg, c);
+    }
+
+    // Parse type.
+    if (it == end) report_error("invalid format string");
+    char type = static_cast<char>(*it++);
+    if (is_integral_type(arg.type())) {
+      // Normalize type.
+      switch (type) {
+      case 'i':
+      case 'u': type = 'd'; break;
+      case 'c':
+        arg.visit(char_converter<basic_printf_context<Char>>(arg));
+        break;
+      }
+    }
+    bool upper = false;
+    specs.set_type(parse_printf_presentation_type(type, arg.type(), upper));
+    if (specs.type() == presentation_type::none)
+      report_error("invalid format specifier");
+    if (upper) specs.set_upper();
+
+    start = it;
+
+    // Format argument.
+    arg.visit(printf_arg_formatter<Char>(out, specs, context));
+  }
+  write(out, basic_string_view<Char>(start, to_unsigned(it - start)));
+}
+}  // namespace detail
+
+using printf_context = basic_printf_context<char>;
+using wprintf_context = basic_printf_context<wchar_t>;
+
+using printf_args = basic_format_args<printf_context>;
+using wprintf_args = basic_format_args<wprintf_context>;
+
+/// Constructs an `format_arg_store` object that contains references to
+/// arguments and can be implicitly converted to `printf_args`.
+template <typename Char = char, typename... T>
+inline auto make_printf_args(T&... args)
+    -> decltype(fmt::make_format_args<basic_printf_context<Char>>(args...)) {
+  return fmt::make_format_args<basic_printf_context<Char>>(args...);
+}
+
+template <typename Char> struct vprintf_args {
+  using type = basic_format_args<basic_printf_context<Char>>;
+};
+
+template <typename Char>
+inline auto vsprintf(basic_string_view<Char> fmt,
+                     typename vprintf_args<Char>::type args)
+    -> std::basic_string<Char> {
+  auto buf = basic_memory_buffer<Char>();
+  detail::vprintf(buf, fmt, args);
+  return {buf.data(), buf.size()};
+}
+
+/**
+ * Formats `args` according to specifications in `fmt` and returns the result
+ * as as string.
+ *
+ * **Example**:
+ *
+ *     std::string message = fmt::sprintf("The answer is %d", 42);
+ */
+template <typename S, typename... T, typename Char = detail::char_t<S>>
+inline auto sprintf(const S& fmt, const T&... args) -> std::basic_string<Char> {
+  return vsprintf(detail::to_string_view(fmt),
+                  fmt::make_format_args<basic_printf_context<Char>>(args...));
+}
+
+template <typename Char>
+inline auto vfprintf(std::FILE* f, basic_string_view<Char> fmt,
+                     typename vprintf_args<Char>::type args) -> int {
+  auto buf = basic_memory_buffer<Char>();
+  detail::vprintf(buf, fmt, args);
+  size_t size = buf.size();
+  return std::fwrite(buf.data(), sizeof(Char), size, f) < size
+             ? -1
+             : static_cast<int>(size);
+}
+
+/**
+ * Formats `args` according to specifications in `fmt` and writes the output
+ * to `f`.
+ *
+ * **Example**:
+ *
+ *     fmt::fprintf(stderr, "Don't %s!", "panic");
+ */
+template <typename S, typename... T, typename Char = detail::char_t<S>>
+inline auto fprintf(std::FILE* f, const S& fmt, const T&... args) -> int {
+  return vfprintf(f, detail::to_string_view(fmt),
+                  make_printf_args<Char>(args...));
+}
+
+template <typename Char>
+FMT_DEPRECATED inline auto vprintf(basic_string_view<Char> fmt,
+                                   typename vprintf_args<Char>::type args)
+    -> int {
+  return vfprintf(stdout, fmt, args);
+}
+
+/**
+ * Formats `args` according to specifications in `fmt` and writes the output
+ * to `stdout`.
+ *
+ * **Example**:
+ *
+ *   fmt::printf("Elapsed time: %.2f seconds", 1.23);
+ */
+template <typename... T>
+inline auto printf(string_view fmt, const T&... args) -> int {
+  return vfprintf(stdout, fmt, make_printf_args(args...));
+}
+template <typename... T>
+FMT_DEPRECATED inline auto printf(basic_string_view<wchar_t> fmt,
+                                  const T&... args) -> int {
+  return vfprintf(stdout, fmt, make_printf_args<wchar_t>(args...));
+}
+
+FMT_END_EXPORT
+FMT_END_NAMESPACE
+
+#endif  // FMT_PRINTF_H_

spdlog/fmt/bundled/ranges.h

@@ -0,0 +1,850 @@
+// Formatting library for C++ - range and tuple support
+//
+// Copyright (c) 2012 - present, Victor Zverovich and {fmt} contributors
+// All rights reserved.
+//
+// For the license information refer to format.h.
+
+#ifndef FMT_RANGES_H_
+#define FMT_RANGES_H_
+
+#ifndef FMT_MODULE
+#  include <initializer_list>
+#  include <iterator>
+#  include <string>
+#  include <tuple>
+#  include <type_traits>
+#  include <utility>
+#endif
+
+#include "format.h"
+
+FMT_BEGIN_NAMESPACE
+
+FMT_EXPORT
+enum class range_format { disabled, map, set, sequence, string, debug_string };
+
+namespace detail {
+
+template <typename T> class is_map {
+  template <typename U> static auto check(U*) -> typename U::mapped_type;
+  template <typename> static void check(...);
+
+ public:
+  static constexpr const bool value =
+      !std::is_void<decltype(check<T>(nullptr))>::value;
+};
+
+template <typename T> class is_set {
+  template <typename U> static auto check(U*) -> typename U::key_type;
+  template <typename> static void check(...);
+
+ public:
+  static constexpr const bool value =
+      !std::is_void<decltype(check<T>(nullptr))>::value && !is_map<T>::value;
+};
+
+// C array overload
+template <typename T, std::size_t N>
+auto range_begin(const T (&arr)[N]) -> const T* {
+  return arr;
+}
+template <typename T, std::size_t N>
+auto range_end(const T (&arr)[N]) -> const T* {
+  return arr + N;
+}
+
+template <typename T, typename Enable = void>
+struct has_member_fn_begin_end_t : std::false_type {};
+
+template <typename T>
+struct has_member_fn_begin_end_t<T, void_t<decltype(*std::declval<T>().begin()),
+                                           decltype(std::declval<T>().end())>>
+    : std::true_type {};
+
+// Member function overloads.
+template <typename T>
+auto range_begin(T&& rng) -> decltype(static_cast<T&&>(rng).begin()) {
+  return static_cast<T&&>(rng).begin();
+}
+template <typename T>
+auto range_end(T&& rng) -> decltype(static_cast<T&&>(rng).end()) {
+  return static_cast<T&&>(rng).end();
+}
+
+// ADL overloads. Only participate in overload resolution if member functions
+// are not found.
+template <typename T>
+auto range_begin(T&& rng)
+    -> enable_if_t<!has_member_fn_begin_end_t<T&&>::value,
+                   decltype(begin(static_cast<T&&>(rng)))> {
+  return begin(static_cast<T&&>(rng));
+}
+template <typename T>
+auto range_end(T&& rng) -> enable_if_t<!has_member_fn_begin_end_t<T&&>::value,
+                                       decltype(end(static_cast<T&&>(rng)))> {
+  return end(static_cast<T&&>(rng));
+}
+
+template <typename T, typename Enable = void>
+struct has_const_begin_end : std::false_type {};
+template <typename T, typename Enable = void>
+struct has_mutable_begin_end : std::false_type {};
+
+template <typename T>
+struct has_const_begin_end<
+    T, void_t<decltype(*detail::range_begin(
+                  std::declval<const remove_cvref_t<T>&>())),
+              decltype(detail::range_end(
+                  std::declval<const remove_cvref_t<T>&>()))>>
+    : std::true_type {};
+
+template <typename T>
+struct has_mutable_begin_end<
+    T, void_t<decltype(*detail::range_begin(std::declval<T&>())),
+              decltype(detail::range_end(std::declval<T&>())),
+              // the extra int here is because older versions of MSVC don't
+              // SFINAE properly unless there are distinct types
+              int>> : std::true_type {};
+
+template <typename T, typename _ = void> struct is_range_ : std::false_type {};
+template <typename T>
+struct is_range_<T, void>
+    : std::integral_constant<bool, (has_const_begin_end<T>::value ||
+                                    has_mutable_begin_end<T>::value)> {};
+
+// tuple_size and tuple_element check.
+template <typename T> class is_tuple_like_ {
+  template <typename U, typename V = typename std::remove_cv<U>::type>
+  static auto check(U* p) -> decltype(std::tuple_size<V>::value, 0);
+  template <typename> static void check(...);
+
+ public:
+  static constexpr const bool value =
+      !std::is_void<decltype(check<T>(nullptr))>::value;
+};
+
+// Check for integer_sequence
+#if defined(__cpp_lib_integer_sequence) || FMT_MSC_VERSION >= 1900
+template <typename T, T... N>
+using integer_sequence = std::integer_sequence<T, N...>;
+template <size_t... N> using index_sequence = std::index_sequence<N...>;
+template <size_t N> using make_index_sequence = std::make_index_sequence<N>;
+#else
+template <typename T, T... N> struct integer_sequence {
+  using value_type = T;
+
+  static FMT_CONSTEXPR auto size() -> size_t { return sizeof...(N); }
+};
+
+template <size_t... N> using index_sequence = integer_sequence<size_t, N...>;
+
+template <typename T, size_t N, T... Ns>
+struct make_integer_sequence : make_integer_sequence<T, N - 1, N - 1, Ns...> {};
+template <typename T, T... Ns>
+struct make_integer_sequence<T, 0, Ns...> : integer_sequence<T, Ns...> {};
+
+template <size_t N>
+using make_index_sequence = make_integer_sequence<size_t, N>;
+#endif
+
+template <typename T>
+using tuple_index_sequence = make_index_sequence<std::tuple_size<T>::value>;
+
+template <typename T, typename C, bool = is_tuple_like_<T>::value>
+class is_tuple_formattable_ {
+ public:
+  static constexpr const bool value = false;
+};
+template <typename T, typename C> class is_tuple_formattable_<T, C, true> {
+  template <size_t... Is>
+  static auto all_true(index_sequence<Is...>,
+                       integer_sequence<bool, (Is >= 0)...>) -> std::true_type;
+  static auto all_true(...) -> std::false_type;
+
+  template <size_t... Is>
+  static auto check(index_sequence<Is...>) -> decltype(all_true(
+      index_sequence<Is...>{},
+      integer_sequence<bool,
+                       (is_formattable<typename std::tuple_element<Is, T>::type,
+                                       C>::value)...>{}));
+
+ public:
+  static constexpr const bool value =
+      decltype(check(tuple_index_sequence<T>{}))::value;
+};
+
+template <typename Tuple, typename F, size_t... Is>
+FMT_CONSTEXPR void for_each(index_sequence<Is...>, Tuple&& t, F&& f) {
+  using std::get;
+  // Using a free function get<Is>(Tuple) now.
+  const int unused[] = {0, ((void)f(get<Is>(t)), 0)...};
+  ignore_unused(unused);
+}
+
+template <typename Tuple, typename F>
+FMT_CONSTEXPR void for_each(Tuple&& t, F&& f) {
+  for_each(tuple_index_sequence<remove_cvref_t<Tuple>>(),
+           std::forward<Tuple>(t), std::forward<F>(f));
+}
+
+template <typename Tuple1, typename Tuple2, typename F, size_t... Is>
+void for_each2(index_sequence<Is...>, Tuple1&& t1, Tuple2&& t2, F&& f) {
+  using std::get;
+  const int unused[] = {0, ((void)f(get<Is>(t1), get<Is>(t2)), 0)...};
+  ignore_unused(unused);
+}
+
+template <typename Tuple1, typename Tuple2, typename F>
+void for_each2(Tuple1&& t1, Tuple2&& t2, F&& f) {
+  for_each2(tuple_index_sequence<remove_cvref_t<Tuple1>>(),
+            std::forward<Tuple1>(t1), std::forward<Tuple2>(t2),
+            std::forward<F>(f));
+}
+
+namespace tuple {
+// Workaround a bug in MSVC 2019 (v140).
+template <typename Char, typename... T>
+using result_t = std::tuple<formatter<remove_cvref_t<T>, Char>...>;
+
+using std::get;
+template <typename Tuple, typename Char, std::size_t... Is>
+auto get_formatters(index_sequence<Is...>)
+    -> result_t<Char, decltype(get<Is>(std::declval<Tuple>()))...>;
+}  // namespace tuple
+
+#if FMT_MSC_VERSION && FMT_MSC_VERSION < 1920
+// Older MSVC doesn't get the reference type correctly for arrays.
+template <typename R> struct range_reference_type_impl {
+  using type = decltype(*detail::range_begin(std::declval<R&>()));
+};
+
+template <typename T, std::size_t N> struct range_reference_type_impl<T[N]> {
+  using type = T&;
+};
+
+template <typename T>
+using range_reference_type = typename range_reference_type_impl<T>::type;
+#else
+template <typename Range>
+using range_reference_type =
+    decltype(*detail::range_begin(std::declval<Range&>()));
+#endif
+
+// We don't use the Range's value_type for anything, but we do need the Range's
+// reference type, with cv-ref stripped.
+template <typename Range>
+using uncvref_type = remove_cvref_t<range_reference_type<Range>>;
+
+template <typename Formatter>
+FMT_CONSTEXPR auto maybe_set_debug_format(Formatter& f, bool set)
+    -> decltype(f.set_debug_format(set)) {
+  f.set_debug_format(set);
+}
+template <typename Formatter>
+FMT_CONSTEXPR void maybe_set_debug_format(Formatter&, ...) {}
+
+template <typename T>
+struct range_format_kind_
+    : std::integral_constant<range_format,
+                             std::is_same<uncvref_type<T>, T>::value
+                                 ? range_format::disabled
+                             : is_map<T>::value ? range_format::map
+                             : is_set<T>::value ? range_format::set
+                                                : range_format::sequence> {};
+
+template <range_format K>
+using range_format_constant = std::integral_constant<range_format, K>;
+
+// These are not generic lambdas for compatibility with C++11.
+template <typename Char> struct parse_empty_specs {
+  template <typename Formatter> FMT_CONSTEXPR void operator()(Formatter& f) {
+    f.parse(ctx);
+    detail::maybe_set_debug_format(f, true);
+  }
+  parse_context<Char>& ctx;
+};
+template <typename FormatContext> struct format_tuple_element {
+  using char_type = typename FormatContext::char_type;
+
+  template <typename T>
+  void operator()(const formatter<T, char_type>& f, const T& v) {
+    if (i > 0) ctx.advance_to(detail::copy<char_type>(separator, ctx.out()));
+    ctx.advance_to(f.format(v, ctx));
+    ++i;
+  }
+
+  int i;
+  FormatContext& ctx;
+  basic_string_view<char_type> separator;
+};
+
+}  // namespace detail
+
+template <typename T> struct is_tuple_like {
+  static constexpr const bool value =
+      detail::is_tuple_like_<T>::value && !detail::is_range_<T>::value;
+};
+
+template <typename T, typename C> struct is_tuple_formattable {
+  static constexpr const bool value =
+      detail::is_tuple_formattable_<T, C>::value;
+};
+
+template <typename Tuple, typename Char>
+struct formatter<Tuple, Char,
+                 enable_if_t<fmt::is_tuple_like<Tuple>::value &&
+                             fmt::is_tuple_formattable<Tuple, Char>::value>> {
+ private:
+  decltype(detail::tuple::get_formatters<Tuple, Char>(
+      detail::tuple_index_sequence<Tuple>())) formatters_;
+
+  basic_string_view<Char> separator_ = detail::string_literal<Char, ',', ' '>{};
+  basic_string_view<Char> opening_bracket_ =
+      detail::string_literal<Char, '('>{};
+  basic_string_view<Char> closing_bracket_ =
+      detail::string_literal<Char, ')'>{};
+
+ public:
+  FMT_CONSTEXPR formatter() {}
+
+  FMT_CONSTEXPR void set_separator(basic_string_view<Char> sep) {
+    separator_ = sep;
+  }
+
+  FMT_CONSTEXPR void set_brackets(basic_string_view<Char> open,
+                                  basic_string_view<Char> close) {
+    opening_bracket_ = open;
+    closing_bracket_ = close;
+  }
+
+  FMT_CONSTEXPR auto parse(parse_context<Char>& ctx) -> const Char* {
+    auto it = ctx.begin();
+    auto end = ctx.end();
+    if (it != end && detail::to_ascii(*it) == 'n') {
+      ++it;
+      set_brackets({}, {});
+      set_separator({});
+    }
+    if (it != end && *it != '}') report_error("invalid format specifier");
+    ctx.advance_to(it);
+    detail::for_each(formatters_, detail::parse_empty_specs<Char>{ctx});
+    return it;
+  }
+
+  template <typename FormatContext>
+  auto format(const Tuple& value, FormatContext& ctx) const
+      -> decltype(ctx.out()) {
+    ctx.advance_to(detail::copy<Char>(opening_bracket_, ctx.out()));
+    detail::for_each2(
+        formatters_, value,
+        detail::format_tuple_element<FormatContext>{0, ctx, separator_});
+    return detail::copy<Char>(closing_bracket_, ctx.out());
+  }
+};
+
+template <typename T, typename Char> struct is_range {
+  static constexpr const bool value =
+      detail::is_range_<T>::value && !detail::has_to_string_view<T>::value;
+};
+
+namespace detail {
+
+template <typename Char, typename Element>
+using range_formatter_type = formatter<remove_cvref_t<Element>, Char>;
+
+template <typename R>
+using maybe_const_range =
+    conditional_t<has_const_begin_end<R>::value, const R, R>;
+
+template <typename R, typename Char>
+struct is_formattable_delayed
+    : is_formattable<uncvref_type<maybe_const_range<R>>, Char> {};
+}  // namespace detail
+
+template <typename...> struct conjunction : std::true_type {};
+template <typename P> struct conjunction<P> : P {};
+template <typename P1, typename... Pn>
+struct conjunction<P1, Pn...>
+    : conditional_t<bool(P1::value), conjunction<Pn...>, P1> {};
+
+template <typename T, typename Char, typename Enable = void>
+struct range_formatter;
+
+template <typename T, typename Char>
+struct range_formatter<
+    T, Char,
+    enable_if_t<conjunction<std::is_same<T, remove_cvref_t<T>>,
+                            is_formattable<T, Char>>::value>> {
+ private:
+  detail::range_formatter_type<Char, T> underlying_;
+  basic_string_view<Char> separator_ = detail::string_literal<Char, ',', ' '>{};
+  basic_string_view<Char> opening_bracket_ =
+      detail::string_literal<Char, '['>{};
+  basic_string_view<Char> closing_bracket_ =
+      detail::string_literal<Char, ']'>{};
+  bool is_debug = false;
+
+  template <typename Output, typename It, typename Sentinel, typename U = T,
+            FMT_ENABLE_IF(std::is_same<U, Char>::value)>
+  auto write_debug_string(Output& out, It it, Sentinel end) const -> Output {
+    auto buf = basic_memory_buffer<Char>();
+    for (; it != end; ++it) buf.push_back(*it);
+    auto specs = format_specs();
+    specs.set_type(presentation_type::debug);
+    return detail::write<Char>(
+        out, basic_string_view<Char>(buf.data(), buf.size()), specs);
+  }
+
+  template <typename Output, typename It, typename Sentinel, typename U = T,
+            FMT_ENABLE_IF(!std::is_same<U, Char>::value)>
+  auto write_debug_string(Output& out, It, Sentinel) const -> Output {
+    return out;
+  }
+
+ public:
+  FMT_CONSTEXPR range_formatter() {}
+
+  FMT_CONSTEXPR auto underlying() -> detail::range_formatter_type<Char, T>& {
+    return underlying_;
+  }
+
+  FMT_CONSTEXPR void set_separator(basic_string_view<Char> sep) {
+    separator_ = sep;
+  }
+
+  FMT_CONSTEXPR void set_brackets(basic_string_view<Char> open,
+                                  basic_string_view<Char> close) {
+    opening_bracket_ = open;
+    closing_bracket_ = close;
+  }
+
+  FMT_CONSTEXPR auto parse(parse_context<Char>& ctx) -> const Char* {
+    auto it = ctx.begin();
+    auto end = ctx.end();
+    detail::maybe_set_debug_format(underlying_, true);
+    if (it == end) return underlying_.parse(ctx);
+
+    switch (detail::to_ascii(*it)) {
+    case 'n':
+      set_brackets({}, {});
+      ++it;
+      break;
+    case '?':
+      is_debug = true;
+      set_brackets({}, {});
+      ++it;
+      if (it == end || *it != 's') report_error("invalid format specifier");
+      FMT_FALLTHROUGH;
+    case 's':
+      if (!std::is_same<T, Char>::value)
+        report_error("invalid format specifier");
+      if (!is_debug) {
+        set_brackets(detail::string_literal<Char, '"'>{},
+                     detail::string_literal<Char, '"'>{});
+        set_separator({});
+        detail::maybe_set_debug_format(underlying_, false);
+      }
+      ++it;
+      return it;
+    }
+
+    if (it != end && *it != '}') {
+      if (*it != ':') report_error("invalid format specifier");
+      detail::maybe_set_debug_format(underlying_, false);
+      ++it;
+    }
+
+    ctx.advance_to(it);
+    return underlying_.parse(ctx);
+  }
+
+  template <typename R, typename FormatContext>
+  auto format(R&& range, FormatContext& ctx) const -> decltype(ctx.out()) {
+    auto out = ctx.out();
+    auto it = detail::range_begin(range);
+    auto end = detail::range_end(range);
+    if (is_debug) return write_debug_string(out, std::move(it), end);
+
+    out = detail::copy<Char>(opening_bracket_, out);
+    int i = 0;
+    for (; it != end; ++it) {
+      if (i > 0) out = detail::copy<Char>(separator_, out);
+      ctx.advance_to(out);
+      auto&& item = *it;  // Need an lvalue
+      out = underlying_.format(item, ctx);
+      ++i;
+    }
+    out = detail::copy<Char>(closing_bracket_, out);
+    return out;
+  }
+};
+
+FMT_EXPORT
+template <typename T, typename Char, typename Enable = void>
+struct range_format_kind
+    : conditional_t<
+          is_range<T, Char>::value, detail::range_format_kind_<T>,
+          std::integral_constant<range_format, range_format::disabled>> {};
+
+template <typename R, typename Char>
+struct formatter<
+    R, Char,
+    enable_if_t<conjunction<
+        bool_constant<
+            range_format_kind<R, Char>::value != range_format::disabled &&
+            range_format_kind<R, Char>::value != range_format::map &&
+            range_format_kind<R, Char>::value != range_format::string &&
+            range_format_kind<R, Char>::value != range_format::debug_string>,
+        detail::is_formattable_delayed<R, Char>>::value>> {
+ private:
+  using range_type = detail::maybe_const_range<R>;
+  range_formatter<detail::uncvref_type<range_type>, Char> range_formatter_;
+
+ public:
+  using nonlocking = void;
+
+  FMT_CONSTEXPR formatter() {
+    if (detail::const_check(range_format_kind<R, Char>::value !=
+                            range_format::set))
+      return;
+    range_formatter_.set_brackets(detail::string_literal<Char, '{'>{},
+                                  detail::string_literal<Char, '}'>{});
+  }
+
+  FMT_CONSTEXPR auto parse(parse_context<Char>& ctx) -> const Char* {
+    return range_formatter_.parse(ctx);
+  }
+
+  template <typename FormatContext>
+  auto format(range_type& range, FormatContext& ctx) const
+      -> decltype(ctx.out()) {
+    return range_formatter_.format(range, ctx);
+  }
+};
+
+// A map formatter.
+template <typename R, typename Char>
+struct formatter<
+    R, Char,
+    enable_if_t<conjunction<
+        bool_constant<range_format_kind<R, Char>::value == range_format::map>,
+        detail::is_formattable_delayed<R, Char>>::value>> {
+ private:
+  using map_type = detail::maybe_const_range<R>;
+  using element_type = detail::uncvref_type<map_type>;
+
+  decltype(detail::tuple::get_formatters<element_type, Char>(
+      detail::tuple_index_sequence<element_type>())) formatters_;
+  bool no_delimiters_ = false;
+
+ public:
+  FMT_CONSTEXPR formatter() {}
+
+  FMT_CONSTEXPR auto parse(parse_context<Char>& ctx) -> const Char* {
+    auto it = ctx.begin();
+    auto end = ctx.end();
+    if (it != end) {
+      if (detail::to_ascii(*it) == 'n') {
+        no_delimiters_ = true;
+        ++it;
+      }
+      if (it != end && *it != '}') {
+        if (*it != ':') report_error("invalid format specifier");
+        ++it;
+      }
+      ctx.advance_to(it);
+    }
+    detail::for_each(formatters_, detail::parse_empty_specs<Char>{ctx});
+    return it;
+  }
+
+  template <typename FormatContext>
+  auto format(map_type& map, FormatContext& ctx) const -> decltype(ctx.out()) {
+    auto out = ctx.out();
+    basic_string_view<Char> open = detail::string_literal<Char, '{'>{};
+    if (!no_delimiters_) out = detail::copy<Char>(open, out);
+    int i = 0;
+    basic_string_view<Char> sep = detail::string_literal<Char, ',', ' '>{};
+    for (auto&& value : map) {
+      if (i > 0) out = detail::copy<Char>(sep, out);
+      ctx.advance_to(out);
+      detail::for_each2(formatters_, value,
+                        detail::format_tuple_element<FormatContext>{
+                            0, ctx, detail::string_literal<Char, ':', ' '>{}});
+      ++i;
+    }
+    basic_string_view<Char> close = detail::string_literal<Char, '}'>{};
+    if (!no_delimiters_) out = detail::copy<Char>(close, out);
+    return out;
+  }
+};
+
+// A (debug_)string formatter.
+template <typename R, typename Char>
+struct formatter<
+    R, Char,
+    enable_if_t<range_format_kind<R, Char>::value == range_format::string ||
+                range_format_kind<R, Char>::value ==
+                    range_format::debug_string>> {
+ private:
+  using range_type = detail::maybe_const_range<R>;
+  using string_type =
+      conditional_t<std::is_constructible<
+                        detail::std_string_view<Char>,
+                        decltype(detail::range_begin(std::declval<R>())),
+                        decltype(detail::range_end(std::declval<R>()))>::value,
+                    detail::std_string_view<Char>, std::basic_string<Char>>;
+
+  formatter<string_type, Char> underlying_;
+
+ public:
+  FMT_CONSTEXPR auto parse(parse_context<Char>& ctx) -> const Char* {
+    return underlying_.parse(ctx);
+  }
+
+  template <typename FormatContext>
+  auto format(range_type& range, FormatContext& ctx) const
+      -> decltype(ctx.out()) {
+    auto out = ctx.out();
+    if (detail::const_check(range_format_kind<R, Char>::value ==
+                            range_format::debug_string))
+      *out++ = '"';
+    out = underlying_.format(
+        string_type{detail::range_begin(range), detail::range_end(range)}, ctx);
+    if (detail::const_check(range_format_kind<R, Char>::value ==
+                            range_format::debug_string))
+      *out++ = '"';
+    return out;
+  }
+};
+
+template <typename It, typename Sentinel, typename Char = char>
+struct join_view : detail::view {
+  It begin;
+  Sentinel end;
+  basic_string_view<Char> sep;
+
+  join_view(It b, Sentinel e, basic_string_view<Char> s)
+      : begin(std::move(b)), end(e), sep(s) {}
+};
+
+template <typename It, typename Sentinel, typename Char>
+struct formatter<join_view<It, Sentinel, Char>, Char> {
+ private:
+  using value_type =
+#ifdef __cpp_lib_ranges
+      std::iter_value_t<It>;
+#else
+      typename std::iterator_traits<It>::value_type;
+#endif
+  formatter<remove_cvref_t<value_type>, Char> value_formatter_;
+
+  using view = conditional_t<std::is_copy_constructible<It>::value,
+                             const join_view<It, Sentinel, Char>,
+                             join_view<It, Sentinel, Char>>;
+
+ public:
+  using nonlocking = void;
+
+  FMT_CONSTEXPR auto parse(parse_context<Char>& ctx) -> const Char* {
+    return value_formatter_.parse(ctx);
+  }
+
+  template <typename FormatContext>
+  auto format(view& value, FormatContext& ctx) const -> decltype(ctx.out()) {
+    using iter =
+        conditional_t<std::is_copy_constructible<view>::value, It, It&>;
+    iter it = value.begin;
+    auto out = ctx.out();
+    if (it == value.end) return out;
+    out = value_formatter_.format(*it, ctx);
+    ++it;
+    while (it != value.end) {
+      out = detail::copy<Char>(value.sep.begin(), value.sep.end(), out);
+      ctx.advance_to(out);
+      out = value_formatter_.format(*it, ctx);
+      ++it;
+    }
+    return out;
+  }
+};
+
+template <typename Char, typename Tuple> struct tuple_join_view : detail::view {
+  const Tuple& tuple;
+  basic_string_view<Char> sep;
+
+  tuple_join_view(const Tuple& t, basic_string_view<Char> s)
+      : tuple(t), sep{s} {}
+};
+
+// Define FMT_TUPLE_JOIN_SPECIFIERS to enable experimental format specifiers
+// support in tuple_join. It is disabled by default because of issues with
+// the dynamic width and precision.
+#ifndef FMT_TUPLE_JOIN_SPECIFIERS
+#  define FMT_TUPLE_JOIN_SPECIFIERS 0
+#endif
+
+template <typename Char, typename Tuple>
+struct formatter<tuple_join_view<Char, Tuple>, Char,
+                 enable_if_t<is_tuple_like<Tuple>::value>> {
+  FMT_CONSTEXPR auto parse(parse_context<Char>& ctx) -> const Char* {
+    return do_parse(ctx, std::tuple_size<Tuple>());
+  }
+
+  template <typename FormatContext>
+  auto format(const tuple_join_view<Char, Tuple>& value,
+              FormatContext& ctx) const -> typename FormatContext::iterator {
+    return do_format(value, ctx, std::tuple_size<Tuple>());
+  }
+
+ private:
+  decltype(detail::tuple::get_formatters<Tuple, Char>(
+      detail::tuple_index_sequence<Tuple>())) formatters_;
+
+  FMT_CONSTEXPR auto do_parse(parse_context<Char>& ctx,
+                              std::integral_constant<size_t, 0>)
+      -> const Char* {
+    return ctx.begin();
+  }
+
+  template <size_t N>
+  FMT_CONSTEXPR auto do_parse(parse_context<Char>& ctx,
+                              std::integral_constant<size_t, N>)
+      -> const Char* {
+    auto end = ctx.begin();
+#if FMT_TUPLE_JOIN_SPECIFIERS
+    end = std::get<std::tuple_size<Tuple>::value - N>(formatters_).parse(ctx);
+    if (N > 1) {
+      auto end1 = do_parse(ctx, std::integral_constant<size_t, N - 1>());
+      if (end != end1)
+        report_error("incompatible format specs for tuple elements");
+    }
+#endif
+    return end;
+  }
+
+  template <typename FormatContext>
+  auto do_format(const tuple_join_view<Char, Tuple>&, FormatContext& ctx,
+                 std::integral_constant<size_t, 0>) const ->
+      typename FormatContext::iterator {
+    return ctx.out();
+  }
+
+  template <typename FormatContext, size_t N>
+  auto do_format(const tuple_join_view<Char, Tuple>& value, FormatContext& ctx,
+                 std::integral_constant<size_t, N>) const ->
+      typename FormatContext::iterator {
+    using std::get;
+    auto out =
+        std::get<std::tuple_size<Tuple>::value - N>(formatters_)
+            .format(get<std::tuple_size<Tuple>::value - N>(value.tuple), ctx);
+    if (N <= 1) return out;
+    out = detail::copy<Char>(value.sep, out);
+    ctx.advance_to(out);
+    return do_format(value, ctx, std::integral_constant<size_t, N - 1>());
+  }
+};
+
+namespace detail {
+// Check if T has an interface like a container adaptor (e.g. std::stack,
+// std::queue, std::priority_queue).
+template <typename T> class is_container_adaptor_like {
+  template <typename U> static auto check(U* p) -> typename U::container_type;
+  template <typename> static void check(...);
+
+ public:
+  static constexpr const bool value =
+      !std::is_void<decltype(check<T>(nullptr))>::value;
+};
+
+template <typename Container> struct all {
+  const Container& c;
+  auto begin() const -> typename Container::const_iterator { return c.begin(); }
+  auto end() const -> typename Container::const_iterator { return c.end(); }
+};
+}  // namespace detail
+
+template <typename T, typename Char>
+struct formatter<
+    T, Char,
+    enable_if_t<conjunction<detail::is_container_adaptor_like<T>,
+                            bool_constant<range_format_kind<T, Char>::value ==
+                                          range_format::disabled>>::value>>
+    : formatter<detail::all<typename T::container_type>, Char> {
+  using all = detail::all<typename T::container_type>;
+  template <typename FormatContext>
+  auto format(const T& t, FormatContext& ctx) const -> decltype(ctx.out()) {
+    struct getter : T {
+      static auto get(const T& t) -> all {
+        return {t.*(&getter::c)};  // Access c through the derived class.
+      }
+    };
+    return formatter<all>::format(getter::get(t), ctx);
+  }
+};
+
+FMT_BEGIN_EXPORT
+
+/// Returns a view that formats the iterator range `[begin, end)` with elements
+/// separated by `sep`.
+template <typename It, typename Sentinel>
+auto join(It begin, Sentinel end, string_view sep) -> join_view<It, Sentinel> {
+  return {std::move(begin), end, sep};
+}
+
+/**
+ * Returns a view that formats `range` with elements separated by `sep`.
+ *
+ * **Example**:
+ *
+ *     auto v = std::vector<int>{1, 2, 3};
+ *     fmt::print("{}", fmt::join(v, ", "));
+ *     // Output: 1, 2, 3
+ *
+ * `fmt::join` applies passed format specifiers to the range elements:
+ *
+ *     fmt::print("{:02}", fmt::join(v, ", "));
+ *     // Output: 01, 02, 03
+ */
+template <typename Range, FMT_ENABLE_IF(!is_tuple_like<Range>::value)>
+auto join(Range&& r, string_view sep)
+    -> join_view<decltype(detail::range_begin(r)),
+                 decltype(detail::range_end(r))> {
+  return {detail::range_begin(r), detail::range_end(r), sep};
+}
+
+/**
+ * Returns an object that formats `std::tuple` with elements separated by `sep`.
+ *
+ * **Example**:
+ *
+ *     auto t = std::tuple<int, char>{1, 'a'};
+ *     fmt::print("{}", fmt::join(t, ", "));
+ *     // Output: 1, a
+ */
+template <typename Tuple, FMT_ENABLE_IF(is_tuple_like<Tuple>::value)>
+FMT_CONSTEXPR auto join(const Tuple& tuple, string_view sep)
+    -> tuple_join_view<char, Tuple> {
+  return {tuple, sep};
+}
+
+/**
+ * Returns an object that formats `std::initializer_list` with elements
+ * separated by `sep`.
+ *
+ * **Example**:
+ *
+ *     fmt::print("{}", fmt::join({1, 2, 3}, ", "));
+ *     // Output: "1, 2, 3"
+ */
+template <typename T>
+auto join(std::initializer_list<T> list, string_view sep)
+    -> join_view<const T*, const T*> {
+  return join(std::begin(list), std::end(list), sep);
+}
+
+FMT_END_EXPORT
+FMT_END_NAMESPACE
+
+#endif  // FMT_RANGES_H_

spdlog/fmt/bundled/std.h

@@ -0,0 +1,726 @@
+// Formatting library for C++ - formatters for standard library types
+//
+// Copyright (c) 2012 - present, Victor Zverovich
+// All rights reserved.
+//
+// For the license information refer to format.h.
+
+#ifndef FMT_STD_H_
+#define FMT_STD_H_
+
+#include "format.h"
+#include "ostream.h"
+
+#ifndef FMT_MODULE
+#  include <atomic>
+#  include <bitset>
+#  include <complex>
+#  include <cstdlib>
+#  include <exception>
+#  include <functional>
+#  include <memory>
+#  include <thread>
+#  include <type_traits>
+#  include <typeinfo>
+#  include <utility>
+#  include <vector>
+
+// Check FMT_CPLUSPLUS to suppress a bogus warning in MSVC.
+#  if FMT_CPLUSPLUS >= 201703L
+#    if FMT_HAS_INCLUDE(<filesystem>) && \
+        (!defined(FMT_CPP_LIB_FILESYSTEM) || FMT_CPP_LIB_FILESYSTEM != 0)
+#      include <filesystem>
+#    endif
+#    if FMT_HAS_INCLUDE(<variant>)
+#      include <variant>
+#    endif
+#    if FMT_HAS_INCLUDE(<optional>)
+#      include <optional>
+#    endif
+#  endif
+// Use > instead of >= in the version check because <source_location> may be
+// available after C++17 but before C++20 is marked as implemented.
+#  if FMT_CPLUSPLUS > 201703L && FMT_HAS_INCLUDE(<source_location>)
+#    include <source_location>
+#  endif
+#  if FMT_CPLUSPLUS > 202002L && FMT_HAS_INCLUDE(<expected>)
+#    include <expected>
+#  endif
+#endif  // FMT_MODULE
+
+#if FMT_HAS_INCLUDE(<version>)
+#  include <version>
+#endif
+
+// GCC 4 does not support FMT_HAS_INCLUDE.
+#if FMT_HAS_INCLUDE(<cxxabi.h>) || defined(__GLIBCXX__)
+#  include <cxxabi.h>
+// Android NDK with gabi++ library on some architectures does not implement
+// abi::__cxa_demangle().
+#  ifndef __GABIXX_CXXABI_H__
+#    define FMT_HAS_ABI_CXA_DEMANGLE
+#  endif
+#endif
+
+// For older Xcode versions, __cpp_lib_xxx flags are inaccurately defined.
+#ifndef FMT_CPP_LIB_FILESYSTEM
+#  ifdef __cpp_lib_filesystem
+#    define FMT_CPP_LIB_FILESYSTEM __cpp_lib_filesystem
+#  else
+#    define FMT_CPP_LIB_FILESYSTEM 0
+#  endif
+#endif
+
+#ifndef FMT_CPP_LIB_VARIANT
+#  ifdef __cpp_lib_variant
+#    define FMT_CPP_LIB_VARIANT __cpp_lib_variant
+#  else
+#    define FMT_CPP_LIB_VARIANT 0
+#  endif
+#endif
+
+#if FMT_CPP_LIB_FILESYSTEM
+FMT_BEGIN_NAMESPACE
+
+namespace detail {
+
+template <typename Char, typename PathChar>
+auto get_path_string(const std::filesystem::path& p,
+                     const std::basic_string<PathChar>& native) {
+  if constexpr (std::is_same_v<Char, char> && std::is_same_v<PathChar, wchar_t>)
+    return to_utf8<wchar_t>(native, to_utf8_error_policy::replace);
+  else
+    return p.string<Char>();
+}
+
+template <typename Char, typename PathChar>
+void write_escaped_path(basic_memory_buffer<Char>& quoted,
+                        const std::filesystem::path& p,
+                        const std::basic_string<PathChar>& native) {
+  if constexpr (std::is_same_v<Char, char> &&
+                std::is_same_v<PathChar, wchar_t>) {
+    auto buf = basic_memory_buffer<wchar_t>();
+    write_escaped_string<wchar_t>(std::back_inserter(buf), native);
+    bool valid = to_utf8<wchar_t>::convert(quoted, {buf.data(), buf.size()});
+    FMT_ASSERT(valid, "invalid utf16");
+  } else if constexpr (std::is_same_v<Char, PathChar>) {
+    write_escaped_string<std::filesystem::path::value_type>(
+        std::back_inserter(quoted), native);
+  } else {
+    write_escaped_string<Char>(std::back_inserter(quoted), p.string<Char>());
+  }
+}
+
+}  // namespace detail
+
+FMT_EXPORT
+template <typename Char> struct formatter<std::filesystem::path, Char> {
+ private:
+  format_specs specs_;
+  detail::arg_ref<Char> width_ref_;
+  bool debug_ = false;
+  char path_type_ = 0;
+
+ public:
+  FMT_CONSTEXPR void set_debug_format(bool set = true) { debug_ = set; }
+
+  FMT_CONSTEXPR auto parse(parse_context<Char>& ctx) {
+    auto it = ctx.begin(), end = ctx.end();
+    if (it == end) return it;
+
+    it = detail::parse_align(it, end, specs_);
+    if (it == end) return it;
+
+    Char c = *it;
+    if ((c >= '0' && c <= '9') || c == '{')
+      it = detail::parse_width(it, end, specs_, width_ref_, ctx);
+    if (it != end && *it == '?') {
+      debug_ = true;
+      ++it;
+    }
+    if (it != end && (*it == 'g')) path_type_ = detail::to_ascii(*it++);
+    return it;
+  }
+
+  template <typename FormatContext>
+  auto format(const std::filesystem::path& p, FormatContext& ctx) const {
+    auto specs = specs_;
+    auto path_string =
+        !path_type_ ? p.native()
+                    : p.generic_string<std::filesystem::path::value_type>();
+
+    detail::handle_dynamic_spec(specs.dynamic_width(), specs.width, width_ref_,
+                                ctx);
+    if (!debug_) {
+      auto s = detail::get_path_string<Char>(p, path_string);
+      return detail::write(ctx.out(), basic_string_view<Char>(s), specs);
+    }
+    auto quoted = basic_memory_buffer<Char>();
+    detail::write_escaped_path(quoted, p, path_string);
+    return detail::write(ctx.out(),
+                         basic_string_view<Char>(quoted.data(), quoted.size()),
+                         specs);
+  }
+};
+
+class path : public std::filesystem::path {
+ public:
+  auto display_string() const -> std::string {
+    const std::filesystem::path& base = *this;
+    return fmt::format(FMT_STRING("{}"), base);
+  }
+  auto system_string() const -> std::string { return string(); }
+
+  auto generic_display_string() const -> std::string {
+    const std::filesystem::path& base = *this;
+    return fmt::format(FMT_STRING("{:g}"), base);
+  }
+  auto generic_system_string() const -> std::string { return generic_string(); }
+};
+
+FMT_END_NAMESPACE
+#endif  // FMT_CPP_LIB_FILESYSTEM
+
+FMT_BEGIN_NAMESPACE
+FMT_EXPORT
+template <std::size_t N, typename Char>
+struct formatter<std::bitset<N>, Char>
+    : nested_formatter<basic_string_view<Char>, Char> {
+ private:
+  // Functor because C++11 doesn't support generic lambdas.
+  struct writer {
+    const std::bitset<N>& bs;
+
+    template <typename OutputIt>
+    FMT_CONSTEXPR auto operator()(OutputIt out) -> OutputIt {
+      for (auto pos = N; pos > 0; --pos) {
+        out = detail::write<Char>(out, bs[pos - 1] ? Char('1') : Char('0'));
+      }
+
+      return out;
+    }
+  };
+
+ public:
+  template <typename FormatContext>
+  auto format(const std::bitset<N>& bs, FormatContext& ctx) const
+      -> decltype(ctx.out()) {
+    return this->write_padded(ctx, writer{bs});
+  }
+};
+
+FMT_EXPORT
+template <typename Char>
+struct formatter<std::thread::id, Char> : basic_ostream_formatter<Char> {};
+FMT_END_NAMESPACE
+
+#ifdef __cpp_lib_optional
+FMT_BEGIN_NAMESPACE
+FMT_EXPORT
+template <typename T, typename Char>
+struct formatter<std::optional<T>, Char,
+                 std::enable_if_t<is_formattable<T, Char>::value>> {
+ private:
+  formatter<T, Char> underlying_;
+  static constexpr basic_string_view<Char> optional =
+      detail::string_literal<Char, 'o', 'p', 't', 'i', 'o', 'n', 'a', 'l',
+                             '('>{};
+  static constexpr basic_string_view<Char> none =
+      detail::string_literal<Char, 'n', 'o', 'n', 'e'>{};
+
+  template <class U>
+  FMT_CONSTEXPR static auto maybe_set_debug_format(U& u, bool set)
+      -> decltype(u.set_debug_format(set)) {
+    u.set_debug_format(set);
+  }
+
+  template <class U>
+  FMT_CONSTEXPR static void maybe_set_debug_format(U&, ...) {}
+
+ public:
+  FMT_CONSTEXPR auto parse(parse_context<Char>& ctx) {
+    maybe_set_debug_format(underlying_, true);
+    return underlying_.parse(ctx);
+  }
+
+  template <typename FormatContext>
+  auto format(const std::optional<T>& opt, FormatContext& ctx) const
+      -> decltype(ctx.out()) {
+    if (!opt) return detail::write<Char>(ctx.out(), none);
+
+    auto out = ctx.out();
+    out = detail::write<Char>(out, optional);
+    ctx.advance_to(out);
+    out = underlying_.format(*opt, ctx);
+    return detail::write(out, ')');
+  }
+};
+FMT_END_NAMESPACE
+#endif  // __cpp_lib_optional
+
+#if defined(__cpp_lib_expected) || FMT_CPP_LIB_VARIANT
+
+FMT_BEGIN_NAMESPACE
+namespace detail {
+
+template <typename Char, typename OutputIt, typename T>
+auto write_escaped_alternative(OutputIt out, const T& v) -> OutputIt {
+  if constexpr (has_to_string_view<T>::value)
+    return write_escaped_string<Char>(out, detail::to_string_view(v));
+  if constexpr (std::is_same_v<T, Char>) return write_escaped_char(out, v);
+  return write<Char>(out, v);
+}
+
+}  // namespace detail
+
+FMT_END_NAMESPACE
+#endif
+
+#ifdef __cpp_lib_expected
+FMT_BEGIN_NAMESPACE
+
+FMT_EXPORT
+template <typename T, typename E, typename Char>
+struct formatter<std::expected<T, E>, Char,
+                 std::enable_if_t<(std::is_void<T>::value ||
+                                   is_formattable<T, Char>::value) &&
+                                  is_formattable<E, Char>::value>> {
+  FMT_CONSTEXPR auto parse(parse_context<Char>& ctx) -> const Char* {
+    return ctx.begin();
+  }
+
+  template <typename FormatContext>
+  auto format(const std::expected<T, E>& value, FormatContext& ctx) const
+      -> decltype(ctx.out()) {
+    auto out = ctx.out();
+
+    if (value.has_value()) {
+      out = detail::write<Char>(out, "expected(");
+      if constexpr (!std::is_void<T>::value)
+        out = detail::write_escaped_alternative<Char>(out, *value);
+    } else {
+      out = detail::write<Char>(out, "unexpected(");
+      out = detail::write_escaped_alternative<Char>(out, value.error());
+    }
+    *out++ = ')';
+    return out;
+  }
+};
+FMT_END_NAMESPACE
+#endif  // __cpp_lib_expected
+
+#ifdef __cpp_lib_source_location
+FMT_BEGIN_NAMESPACE
+FMT_EXPORT
+template <> struct formatter<std::source_location> {
+  FMT_CONSTEXPR auto parse(parse_context<>& ctx) { return ctx.begin(); }
+
+  template <typename FormatContext>
+  auto format(const std::source_location& loc, FormatContext& ctx) const
+      -> decltype(ctx.out()) {
+    auto out = ctx.out();
+    out = detail::write(out, loc.file_name());
+    out = detail::write(out, ':');
+    out = detail::write<char>(out, loc.line());
+    out = detail::write(out, ':');
+    out = detail::write<char>(out, loc.column());
+    out = detail::write(out, ": ");
+    out = detail::write(out, loc.function_name());
+    return out;
+  }
+};
+FMT_END_NAMESPACE
+#endif
+
+#if FMT_CPP_LIB_VARIANT
+FMT_BEGIN_NAMESPACE
+namespace detail {
+
+template <typename T>
+using variant_index_sequence =
+    std::make_index_sequence<std::variant_size<T>::value>;
+
+template <typename> struct is_variant_like_ : std::false_type {};
+template <typename... Types>
+struct is_variant_like_<std::variant<Types...>> : std::true_type {};
+
+// formattable element check.
+template <typename T, typename C> class is_variant_formattable_ {
+  template <std::size_t... Is>
+  static std::conjunction<
+      is_formattable<std::variant_alternative_t<Is, T>, C>...>
+      check(std::index_sequence<Is...>);
+
+ public:
+  static constexpr const bool value =
+      decltype(check(variant_index_sequence<T>{}))::value;
+};
+
+}  // namespace detail
+
+template <typename T> struct is_variant_like {
+  static constexpr const bool value = detail::is_variant_like_<T>::value;
+};
+
+template <typename T, typename C> struct is_variant_formattable {
+  static constexpr const bool value =
+      detail::is_variant_formattable_<T, C>::value;
+};
+
+FMT_EXPORT
+template <typename Char> struct formatter<std::monostate, Char> {
+  FMT_CONSTEXPR auto parse(parse_context<Char>& ctx) -> const Char* {
+    return ctx.begin();
+  }
+
+  template <typename FormatContext>
+  auto format(const std::monostate&, FormatContext& ctx) const
+      -> decltype(ctx.out()) {
+    return detail::write<Char>(ctx.out(), "monostate");
+  }
+};
+
+FMT_EXPORT
+template <typename Variant, typename Char>
+struct formatter<
+    Variant, Char,
+    std::enable_if_t<std::conjunction_v<
+        is_variant_like<Variant>, is_variant_formattable<Variant, Char>>>> {
+  FMT_CONSTEXPR auto parse(parse_context<Char>& ctx) -> const Char* {
+    return ctx.begin();
+  }
+
+  template <typename FormatContext>
+  auto format(const Variant& value, FormatContext& ctx) const
+      -> decltype(ctx.out()) {
+    auto out = ctx.out();
+
+    out = detail::write<Char>(out, "variant(");
+    FMT_TRY {
+      std::visit(
+          [&](const auto& v) {
+            out = detail::write_escaped_alternative<Char>(out, v);
+          },
+          value);
+    }
+    FMT_CATCH(const std::bad_variant_access&) {
+      detail::write<Char>(out, "valueless by exception");
+    }
+    *out++ = ')';
+    return out;
+  }
+};
+FMT_END_NAMESPACE
+#endif  // FMT_CPP_LIB_VARIANT
+
+FMT_BEGIN_NAMESPACE
+FMT_EXPORT
+template <> struct formatter<std::error_code> {
+ private:
+  format_specs specs_;
+  detail::arg_ref<char> width_ref_;
+
+ public:
+  FMT_CONSTEXPR auto parse(parse_context<>& ctx) -> const char* {
+    auto it = ctx.begin(), end = ctx.end();
+    if (it == end) return it;
+
+    it = detail::parse_align(it, end, specs_);
+    if (it == end) return it;
+
+    char c = *it;
+    if ((c >= '0' && c <= '9') || c == '{')
+      it = detail::parse_width(it, end, specs_, width_ref_, ctx);
+    return it;
+  }
+
+  template <typename FormatContext>
+  FMT_CONSTEXPR20 auto format(const std::error_code& ec,
+                              FormatContext& ctx) const -> decltype(ctx.out()) {
+    auto specs = specs_;
+    detail::handle_dynamic_spec(specs.dynamic_width(), specs.width, width_ref_,
+                                ctx);
+    memory_buffer buf;
+    buf.append(string_view(ec.category().name()));
+    buf.push_back(':');
+    detail::write<char>(appender(buf), ec.value());
+    return detail::write<char>(ctx.out(), string_view(buf.data(), buf.size()),
+                               specs);
+  }
+};
+
+#if FMT_USE_RTTI
+namespace detail {
+
+template <typename Char, typename OutputIt>
+auto write_demangled_name(OutputIt out, const std::type_info& ti) -> OutputIt {
+#  ifdef FMT_HAS_ABI_CXA_DEMANGLE
+  int status = 0;
+  std::size_t size = 0;
+  std::unique_ptr<char, void (*)(void*)> demangled_name_ptr(
+      abi::__cxa_demangle(ti.name(), nullptr, &size, &status), &std::free);
+
+  string_view demangled_name_view;
+  if (demangled_name_ptr) {
+    demangled_name_view = demangled_name_ptr.get();
+
+    // Normalization of stdlib inline namespace names.
+    // libc++ inline namespaces.
+    //  std::__1::*       -> std::*
+    //  std::__1::__fs::* -> std::*
+    // libstdc++ inline namespaces.
+    //  std::__cxx11::*             -> std::*
+    //  std::filesystem::__cxx11::* -> std::filesystem::*
+    if (demangled_name_view.starts_with("std::")) {
+      char* begin = demangled_name_ptr.get();
+      char* to = begin + 5;  // std::
+      for (char *from = to, *end = begin + demangled_name_view.size();
+           from < end;) {
+        // This is safe, because demangled_name is NUL-terminated.
+        if (from[0] == '_' && from[1] == '_') {
+          char* next = from + 1;
+          while (next < end && *next != ':') next++;
+          if (next[0] == ':' && next[1] == ':') {
+            from = next + 2;
+            continue;
+          }
+        }
+        *to++ = *from++;
+      }
+      demangled_name_view = {begin, detail::to_unsigned(to - begin)};
+    }
+  } else {
+    demangled_name_view = string_view(ti.name());
+  }
+  return detail::write_bytes<Char>(out, demangled_name_view);
+#  elif FMT_MSC_VERSION
+  const string_view demangled_name(ti.name());
+  for (std::size_t i = 0; i < demangled_name.size(); ++i) {
+    auto sub = demangled_name;
+    sub.remove_prefix(i);
+    if (sub.starts_with("enum ")) {
+      i += 4;
+      continue;
+    }
+    if (sub.starts_with("class ") || sub.starts_with("union ")) {
+      i += 5;
+      continue;
+    }
+    if (sub.starts_with("struct ")) {
+      i += 6;
+      continue;
+    }
+    if (*sub.begin() != ' ') *out++ = *sub.begin();
+  }
+  return out;
+#  else
+  return detail::write_bytes<Char>(out, string_view(ti.name()));
+#  endif
+}
+
+}  // namespace detail
+
+FMT_EXPORT
+template <typename Char>
+struct formatter<std::type_info, Char  // DEPRECATED! Mixing code unit types.
+                 > {
+ public:
+  FMT_CONSTEXPR auto parse(parse_context<Char>& ctx) -> const Char* {
+    return ctx.begin();
+  }
+
+  template <typename Context>
+  auto format(const std::type_info& ti, Context& ctx) const
+      -> decltype(ctx.out()) {
+    return detail::write_demangled_name<Char>(ctx.out(), ti);
+  }
+};
+#endif
+
+FMT_EXPORT
+template <typename T, typename Char>
+struct formatter<
+    T, Char,  // DEPRECATED! Mixing code unit types.
+    typename std::enable_if<std::is_base_of<std::exception, T>::value>::type> {
+ private:
+  bool with_typename_ = false;
+
+ public:
+  FMT_CONSTEXPR auto parse(parse_context<Char>& ctx) -> const Char* {
+    auto it = ctx.begin();
+    auto end = ctx.end();
+    if (it == end || *it == '}') return it;
+    if (*it == 't') {
+      ++it;
+      with_typename_ = FMT_USE_RTTI != 0;
+    }
+    return it;
+  }
+
+  template <typename Context>
+  auto format(const std::exception& ex, Context& ctx) const
+      -> decltype(ctx.out()) {
+    auto out = ctx.out();
+#if FMT_USE_RTTI
+    if (with_typename_) {
+      out = detail::write_demangled_name<Char>(out, typeid(ex));
+      *out++ = ':';
+      *out++ = ' ';
+    }
+#endif
+    return detail::write_bytes<Char>(out, string_view(ex.what()));
+  }
+};
+
+namespace detail {
+
+template <typename T, typename Enable = void>
+struct has_flip : std::false_type {};
+
+template <typename T>
+struct has_flip<T, void_t<decltype(std::declval<T>().flip())>>
+    : std::true_type {};
+
+template <typename T> struct is_bit_reference_like {
+  static constexpr const bool value =
+      std::is_convertible<T, bool>::value &&
+      std::is_nothrow_assignable<T, bool>::value && has_flip<T>::value;
+};
+
+#ifdef _LIBCPP_VERSION
+
+// Workaround for libc++ incompatibility with C++ standard.
+// According to the Standard, `bitset::operator[] const` returns bool.
+template <typename C>
+struct is_bit_reference_like<std::__bit_const_reference<C>> {
+  static constexpr const bool value = true;
+};
+
+#endif
+
+}  // namespace detail
+
+// We can't use std::vector<bool, Allocator>::reference and
+// std::bitset<N>::reference because the compiler can't deduce Allocator and N
+// in partial specialization.
+FMT_EXPORT
+template <typename BitRef, typename Char>
+struct formatter<BitRef, Char,
+                 enable_if_t<detail::is_bit_reference_like<BitRef>::value>>
+    : formatter<bool, Char> {
+  template <typename FormatContext>
+  FMT_CONSTEXPR auto format(const BitRef& v, FormatContext& ctx) const
+      -> decltype(ctx.out()) {
+    return formatter<bool, Char>::format(v, ctx);
+  }
+};
+
+template <typename T, typename Deleter>
+auto ptr(const std::unique_ptr<T, Deleter>& p) -> const void* {
+  return p.get();
+}
+template <typename T> auto ptr(const std::shared_ptr<T>& p) -> const void* {
+  return p.get();
+}
+
+FMT_EXPORT
+template <typename T, typename Char>
+struct formatter<std::atomic<T>, Char,
+                 enable_if_t<is_formattable<T, Char>::value>>
+    : formatter<T, Char> {
+  template <typename FormatContext>
+  auto format(const std::atomic<T>& v, FormatContext& ctx) const
+      -> decltype(ctx.out()) {
+    return formatter<T, Char>::format(v.load(), ctx);
+  }
+};
+
+#ifdef __cpp_lib_atomic_flag_test
+FMT_EXPORT
+template <typename Char>
+struct formatter<std::atomic_flag, Char> : formatter<bool, Char> {
+  template <typename FormatContext>
+  auto format(const std::atomic_flag& v, FormatContext& ctx) const
+      -> decltype(ctx.out()) {
+    return formatter<bool, Char>::format(v.test(), ctx);
+  }
+};
+#endif  // __cpp_lib_atomic_flag_test
+
+FMT_EXPORT
+template <typename T, typename Char> struct formatter<std::complex<T>, Char> {
+ private:
+  detail::dynamic_format_specs<Char> specs_;
+
+  template <typename FormatContext, typename OutputIt>
+  FMT_CONSTEXPR auto do_format(const std::complex<T>& c,
+                               detail::dynamic_format_specs<Char>& specs,
+                               FormatContext& ctx, OutputIt out) const
+      -> OutputIt {
+    if (c.real() != 0) {
+      *out++ = Char('(');
+      out = detail::write<Char>(out, c.real(), specs, ctx.locale());
+      specs.set_sign(sign::plus);
+      out = detail::write<Char>(out, c.imag(), specs, ctx.locale());
+      if (!detail::isfinite(c.imag())) *out++ = Char(' ');
+      *out++ = Char('i');
+      *out++ = Char(')');
+      return out;
+    }
+    out = detail::write<Char>(out, c.imag(), specs, ctx.locale());
+    if (!detail::isfinite(c.imag())) *out++ = Char(' ');
+    *out++ = Char('i');
+    return out;
+  }
+
+ public:
+  FMT_CONSTEXPR auto parse(parse_context<Char>& ctx) -> const Char* {
+    if (ctx.begin() == ctx.end() || *ctx.begin() == '}') return ctx.begin();
+    return parse_format_specs(ctx.begin(), ctx.end(), specs_, ctx,
+                              detail::type_constant<T, Char>::value);
+  }
+
+  template <typename FormatContext>
+  auto format(const std::complex<T>& c, FormatContext& ctx) const
+      -> decltype(ctx.out()) {
+    auto specs = specs_;
+    if (specs.dynamic()) {
+      detail::handle_dynamic_spec(specs.dynamic_width(), specs.width,
+                                  specs.width_ref, ctx);
+      detail::handle_dynamic_spec(specs.dynamic_precision(), specs.precision,
+                                  specs.precision_ref, ctx);
+    }
+
+    if (specs.width == 0) return do_format(c, specs, ctx, ctx.out());
+    auto buf = basic_memory_buffer<Char>();
+
+    auto outer_specs = format_specs();
+    outer_specs.width = specs.width;
+    outer_specs.copy_fill_from(specs);
+    outer_specs.set_align(specs.align());
+
+    specs.width = 0;
+    specs.set_fill({});
+    specs.set_align(align::none);
+
+    do_format(c, specs, ctx, basic_appender<Char>(buf));
+    return detail::write<Char>(ctx.out(),
+                               basic_string_view<Char>(buf.data(), buf.size()),
+                               outer_specs);
+  }
+};
+
+FMT_EXPORT
+template <typename T, typename Char>
+struct formatter<std::reference_wrapper<T>, Char,
+                 enable_if_t<is_formattable<remove_cvref_t<T>, Char>::value>>
+    : formatter<remove_cvref_t<T>, Char> {
+  template <typename FormatContext>
+  auto format(std::reference_wrapper<T> ref, FormatContext& ctx) const
+      -> decltype(ctx.out()) {
+    return formatter<remove_cvref_t<T>, Char>::format(ref.get(), ctx);
+  }
+};
+
+FMT_END_NAMESPACE
+#endif  // FMT_STD_H_

spdlog/fmt/bundled/xchar.h

@@ -0,0 +1,373 @@
+// Formatting library for C++ - optional wchar_t and exotic character support
+//
+// Copyright (c) 2012 - present, Victor Zverovich
+// All rights reserved.
+//
+// For the license information refer to format.h.
+
+#ifndef FMT_XCHAR_H_
+#define FMT_XCHAR_H_
+
+#include "color.h"
+#include "format.h"
+#include "ostream.h"
+#include "ranges.h"
+
+#ifndef FMT_MODULE
+#  include <cwchar>
+#  if FMT_USE_LOCALE
+#    include <locale>
+#  endif
+#endif
+
+FMT_BEGIN_NAMESPACE
+namespace detail {
+
+template <typename T>
+using is_exotic_char = bool_constant<!std::is_same<T, char>::value>;
+
+template <typename S, typename = void> struct format_string_char {};
+
+template <typename S>
+struct format_string_char<
+    S, void_t<decltype(sizeof(detail::to_string_view(std::declval<S>())))>> {
+  using type = char_t<S>;
+};
+
+template <typename S>
+struct format_string_char<
+    S, enable_if_t<std::is_base_of<detail::compile_string, S>::value>> {
+  using type = typename S::char_type;
+};
+
+template <typename S>
+using format_string_char_t = typename format_string_char<S>::type;
+
+inline auto write_loc(basic_appender<wchar_t> out, loc_value value,
+                      const format_specs& specs, locale_ref loc) -> bool {
+#if FMT_USE_LOCALE
+  auto& numpunct =
+      std::use_facet<std::numpunct<wchar_t>>(loc.get<std::locale>());
+  auto separator = std::wstring();
+  auto grouping = numpunct.grouping();
+  if (!grouping.empty()) separator = std::wstring(1, numpunct.thousands_sep());
+  return value.visit(loc_writer<wchar_t>{out, specs, separator, grouping, {}});
+#endif
+  return false;
+}
+}  // namespace detail
+
+FMT_BEGIN_EXPORT
+
+using wstring_view = basic_string_view<wchar_t>;
+using wformat_parse_context = parse_context<wchar_t>;
+using wformat_context = buffered_context<wchar_t>;
+using wformat_args = basic_format_args<wformat_context>;
+using wmemory_buffer = basic_memory_buffer<wchar_t>;
+
+template <typename Char, typename... T> struct basic_fstring {
+ private:
+  basic_string_view<Char> str_;
+
+  static constexpr int num_static_named_args =
+      detail::count_static_named_args<T...>();
+
+  using checker = detail::format_string_checker<
+      Char, static_cast<int>(sizeof...(T)), num_static_named_args,
+      num_static_named_args != detail::count_named_args<T...>()>;
+
+  using arg_pack = detail::arg_pack<T...>;
+
+ public:
+  using t = basic_fstring;
+
+  template <typename S,
+            FMT_ENABLE_IF(
+                std::is_convertible<const S&, basic_string_view<Char>>::value)>
+  FMT_CONSTEVAL FMT_ALWAYS_INLINE basic_fstring(const S& s) : str_(s) {
+    if (FMT_USE_CONSTEVAL)
+      detail::parse_format_string<Char>(s, checker(s, arg_pack()));
+  }
+  template <typename S,
+            FMT_ENABLE_IF(std::is_base_of<detail::compile_string, S>::value&&
+                              std::is_same<typename S::char_type, Char>::value)>
+  FMT_ALWAYS_INLINE basic_fstring(const S&) : str_(S()) {
+    FMT_CONSTEXPR auto sv = basic_string_view<Char>(S());
+    FMT_CONSTEXPR int ignore =
+        (parse_format_string(sv, checker(sv, arg_pack())), 0);
+    detail::ignore_unused(ignore);
+  }
+  basic_fstring(runtime_format_string<Char> fmt) : str_(fmt.str) {}
+
+  operator basic_string_view<Char>() const { return str_; }
+  auto get() const -> basic_string_view<Char> { return str_; }
+};
+
+template <typename Char, typename... T>
+using basic_format_string = basic_fstring<Char, T...>;
+
+template <typename... T>
+using wformat_string = typename basic_format_string<wchar_t, T...>::t;
+inline auto runtime(wstring_view s) -> runtime_format_string<wchar_t> {
+  return {{s}};
+}
+
+template <> struct is_char<wchar_t> : std::true_type {};
+template <> struct is_char<char16_t> : std::true_type {};
+template <> struct is_char<char32_t> : std::true_type {};
+
+#ifdef __cpp_char8_t
+template <> struct is_char<char8_t> : bool_constant<detail::is_utf8_enabled> {};
+#endif
+
+template <typename... T>
+constexpr auto make_wformat_args(T&... args)
+    -> decltype(fmt::make_format_args<wformat_context>(args...)) {
+  return fmt::make_format_args<wformat_context>(args...);
+}
+
+#if !FMT_USE_NONTYPE_TEMPLATE_ARGS
+inline namespace literals {
+inline auto operator""_a(const wchar_t* s, size_t) -> detail::udl_arg<wchar_t> {
+  return {s};
+}
+}  // namespace literals
+#endif
+
+template <typename It, typename Sentinel>
+auto join(It begin, Sentinel end, wstring_view sep)
+    -> join_view<It, Sentinel, wchar_t> {
+  return {begin, end, sep};
+}
+
+template <typename Range, FMT_ENABLE_IF(!is_tuple_like<Range>::value)>
+auto join(Range&& range, wstring_view sep)
+    -> join_view<decltype(std::begin(range)), decltype(std::end(range)),
+                 wchar_t> {
+  return join(std::begin(range), std::end(range), sep);
+}
+
+template <typename T>
+auto join(std::initializer_list<T> list, wstring_view sep)
+    -> join_view<const T*, const T*, wchar_t> {
+  return join(std::begin(list), std::end(list), sep);
+}
+
+template <typename Tuple, FMT_ENABLE_IF(is_tuple_like<Tuple>::value)>
+auto join(const Tuple& tuple, basic_string_view<wchar_t> sep)
+    -> tuple_join_view<wchar_t, Tuple> {
+  return {tuple, sep};
+}
+
+template <typename Char, FMT_ENABLE_IF(!std::is_same<Char, char>::value)>
+auto vformat(basic_string_view<Char> fmt,
+             typename detail::vformat_args<Char>::type args)
+    -> std::basic_string<Char> {
+  auto buf = basic_memory_buffer<Char>();
+  detail::vformat_to(buf, fmt, args);
+  return {buf.data(), buf.size()};
+}
+
+template <typename... T>
+auto format(wformat_string<T...> fmt, T&&... args) -> std::wstring {
+  return vformat(fmt::wstring_view(fmt), fmt::make_wformat_args(args...));
+}
+
+template <typename OutputIt, typename... T>
+auto format_to(OutputIt out, wformat_string<T...> fmt, T&&... args)
+    -> OutputIt {
+  return vformat_to(out, fmt::wstring_view(fmt),
+                    fmt::make_wformat_args(args...));
+}
+
+// Pass char_t as a default template parameter instead of using
+// std::basic_string<char_t<S>> to reduce the symbol size.
+template <typename S, typename... T,
+          typename Char = detail::format_string_char_t<S>,
+          FMT_ENABLE_IF(!std::is_same<Char, char>::value &&
+                        !std::is_same<Char, wchar_t>::value)>
+auto format(const S& fmt, T&&... args) -> std::basic_string<Char> {
+  return vformat(detail::to_string_view(fmt),
+                 fmt::make_format_args<buffered_context<Char>>(args...));
+}
+
+template <typename Locale, typename S,
+          typename Char = detail::format_string_char_t<S>,
+          FMT_ENABLE_IF(detail::is_locale<Locale>::value&&
+                            detail::is_exotic_char<Char>::value)>
+inline auto vformat(const Locale& loc, const S& fmt,
+                    typename detail::vformat_args<Char>::type args)
+    -> std::basic_string<Char> {
+  auto buf = basic_memory_buffer<Char>();
+  detail::vformat_to(buf, detail::to_string_view(fmt), args,
+                     detail::locale_ref(loc));
+  return {buf.data(), buf.size()};
+}
+
+template <typename Locale, typename S, typename... T,
+          typename Char = detail::format_string_char_t<S>,
+          FMT_ENABLE_IF(detail::is_locale<Locale>::value&&
+                            detail::is_exotic_char<Char>::value)>
+inline auto format(const Locale& loc, const S& fmt, T&&... args)
+    -> std::basic_string<Char> {
+  return vformat(loc, detail::to_string_view(fmt),
+                 fmt::make_format_args<buffered_context<Char>>(args...));
+}
+
+template <typename OutputIt, typename S,
+          typename Char = detail::format_string_char_t<S>,
+          FMT_ENABLE_IF(detail::is_output_iterator<OutputIt, Char>::value&&
+                            detail::is_exotic_char<Char>::value)>
+auto vformat_to(OutputIt out, const S& fmt,
+                typename detail::vformat_args<Char>::type args) -> OutputIt {
+  auto&& buf = detail::get_buffer<Char>(out);
+  detail::vformat_to(buf, detail::to_string_view(fmt), args);
+  return detail::get_iterator(buf, out);
+}
+
+template <typename OutputIt, typename S, typename... T,
+          typename Char = detail::format_string_char_t<S>,
+          FMT_ENABLE_IF(detail::is_output_iterator<OutputIt, Char>::value &&
+                        !std::is_same<Char, char>::value &&
+                        !std::is_same<Char, wchar_t>::value)>
+inline auto format_to(OutputIt out, const S& fmt, T&&... args) -> OutputIt {
+  return vformat_to(out, detail::to_string_view(fmt),
+                    fmt::make_format_args<buffered_context<Char>>(args...));
+}
+
+template <typename Locale, typename S, typename OutputIt, typename... Args,
+          typename Char = detail::format_string_char_t<S>,
+          FMT_ENABLE_IF(detail::is_output_iterator<OutputIt, Char>::value&&
+                            detail::is_locale<Locale>::value&&
+                                detail::is_exotic_char<Char>::value)>
+inline auto vformat_to(OutputIt out, const Locale& loc, const S& fmt,
+                       typename detail::vformat_args<Char>::type args)
+    -> OutputIt {
+  auto&& buf = detail::get_buffer<Char>(out);
+  vformat_to(buf, detail::to_string_view(fmt), args, detail::locale_ref(loc));
+  return detail::get_iterator(buf, out);
+}
+
+template <typename Locale, typename OutputIt, typename S, typename... T,
+          typename Char = detail::format_string_char_t<S>,
+          bool enable = detail::is_output_iterator<OutputIt, Char>::value &&
+                        detail::is_locale<Locale>::value &&
+                        detail::is_exotic_char<Char>::value>
+inline auto format_to(OutputIt out, const Locale& loc, const S& fmt,
+                      T&&... args) ->
+    typename std::enable_if<enable, OutputIt>::type {
+  return vformat_to(out, loc, detail::to_string_view(fmt),
+                    fmt::make_format_args<buffered_context<Char>>(args...));
+}
+
+template <typename OutputIt, typename Char, typename... Args,
+          FMT_ENABLE_IF(detail::is_output_iterator<OutputIt, Char>::value&&
+                            detail::is_exotic_char<Char>::value)>
+inline auto vformat_to_n(OutputIt out, size_t n, basic_string_view<Char> fmt,
+                         typename detail::vformat_args<Char>::type args)
+    -> format_to_n_result<OutputIt> {
+  using traits = detail::fixed_buffer_traits;
+  auto buf = detail::iterator_buffer<OutputIt, Char, traits>(out, n);
+  detail::vformat_to(buf, fmt, args);
+  return {buf.out(), buf.count()};
+}
+
+template <typename OutputIt, typename S, typename... T,
+          typename Char = detail::format_string_char_t<S>,
+          FMT_ENABLE_IF(detail::is_output_iterator<OutputIt, Char>::value&&
+                            detail::is_exotic_char<Char>::value)>
+inline auto format_to_n(OutputIt out, size_t n, const S& fmt, T&&... args)
+    -> format_to_n_result<OutputIt> {
+  return vformat_to_n(out, n, fmt::basic_string_view<Char>(fmt),
+                      fmt::make_format_args<buffered_context<Char>>(args...));
+}
+
+template <typename S, typename... T,
+          typename Char = detail::format_string_char_t<S>,
+          FMT_ENABLE_IF(detail::is_exotic_char<Char>::value)>
+inline auto formatted_size(const S& fmt, T&&... args) -> size_t {
+  auto buf = detail::counting_buffer<Char>();
+  detail::vformat_to(buf, detail::to_string_view(fmt),
+                     fmt::make_format_args<buffered_context<Char>>(args...));
+  return buf.count();
+}
+
+inline void vprint(std::FILE* f, wstring_view fmt, wformat_args args) {
+  auto buf = wmemory_buffer();
+  detail::vformat_to(buf, fmt, args);
+  buf.push_back(L'\0');
+  if (std::fputws(buf.data(), f) == -1)
+    FMT_THROW(system_error(errno, FMT_STRING("cannot write to file")));
+}
+
+inline void vprint(wstring_view fmt, wformat_args args) {
+  vprint(stdout, fmt, args);
+}
+
+template <typename... T>
+void print(std::FILE* f, wformat_string<T...> fmt, T&&... args) {
+  return vprint(f, wstring_view(fmt), fmt::make_wformat_args(args...));
+}
+
+template <typename... T> void print(wformat_string<T...> fmt, T&&... args) {
+  return vprint(wstring_view(fmt), fmt::make_wformat_args(args...));
+}
+
+template <typename... T>
+void println(std::FILE* f, wformat_string<T...> fmt, T&&... args) {
+  return print(f, L"{}\n", fmt::format(fmt, std::forward<T>(args)...));
+}
+
+template <typename... T> void println(wformat_string<T...> fmt, T&&... args) {
+  return print(L"{}\n", fmt::format(fmt, std::forward<T>(args)...));
+}
+
+inline auto vformat(const text_style& ts, wstring_view fmt, wformat_args args)
+    -> std::wstring {
+  auto buf = wmemory_buffer();
+  detail::vformat_to(buf, ts, fmt, args);
+  return {buf.data(), buf.size()};
+}
+
+template <typename... T>
+inline auto format(const text_style& ts, wformat_string<T...> fmt, T&&... args)
+    -> std::wstring {
+  return fmt::vformat(ts, fmt, fmt::make_wformat_args(args...));
+}
+
+template <typename... T>
+FMT_DEPRECATED void print(std::FILE* f, const text_style& ts,
+                          wformat_string<T...> fmt, const T&... args) {
+  vprint(f, ts, fmt, fmt::make_wformat_args(args...));
+}
+
+template <typename... T>
+FMT_DEPRECATED void print(const text_style& ts, wformat_string<T...> fmt,
+                          const T&... args) {
+  return print(stdout, ts, fmt, args...);
+}
+
+inline void vprint(std::wostream& os, wstring_view fmt, wformat_args args) {
+  auto buffer = basic_memory_buffer<wchar_t>();
+  detail::vformat_to(buffer, fmt, args);
+  detail::write_buffer(os, buffer);
+}
+
+template <typename... T>
+void print(std::wostream& os, wformat_string<T...> fmt, T&&... args) {
+  vprint(os, fmt, fmt::make_format_args<buffered_context<wchar_t>>(args...));
+}
+
+template <typename... T>
+void println(std::wostream& os, wformat_string<T...> fmt, T&&... args) {
+  print(os, L"{}\n", fmt::format(fmt, std::forward<T>(args)...));
+}
+
+/// Converts `value` to `std::wstring` using the default format for type `T`.
+template <typename T> inline auto to_wstring(const T& value) -> std::wstring {
+  return format(FMT_STRING(L"{}"), value);
+}
+FMT_END_EXPORT
+FMT_END_NAMESPACE
+
+#endif  // FMT_XCHAR_H_

spdlog/fmt/chrono.h

@@ -0,0 +1,23 @@
+//
+// Copyright(c) 2016 Gabi Melman.
+// Distributed under the MIT License (http://opensource.org/licenses/MIT)
+//
+
+#pragma once
+//
+// include bundled or external copy of fmtlib's chrono support
+//
+#include <spdlog/tweakme.h>
+
+#if !defined(SPDLOG_USE_STD_FORMAT)
+    #if !defined(SPDLOG_FMT_EXTERNAL)
+        #ifdef SPDLOG_HEADER_ONLY
+            #ifndef FMT_HEADER_ONLY
+                #define FMT_HEADER_ONLY
+            #endif
+        #endif
+        #include <spdlog/fmt/bundled/chrono.h>
+    #else
+        #include <fmt/chrono.h>
+    #endif
+#endif

spdlog/fmt/compile.h

@@ -0,0 +1,23 @@
+//
+// Copyright(c) 2016 Gabi Melman.
+// Distributed under the MIT License (http://opensource.org/licenses/MIT)
+//
+
+#pragma once
+//
+// include bundled or external copy of fmtlib's compile-time support
+//
+#include <spdlog/tweakme.h>
+
+#if !defined(SPDLOG_USE_STD_FORMAT)
+    #if !defined(SPDLOG_FMT_EXTERNAL)
+        #ifdef SPDLOG_HEADER_ONLY
+            #ifndef FMT_HEADER_ONLY
+                #define FMT_HEADER_ONLY
+            #endif
+        #endif
+        #include <spdlog/fmt/bundled/compile.h>
+    #else
+        #include <fmt/compile.h>
+    #endif
+#endif

spdlog/fmt/fmt.h

@@ -0,0 +1,30 @@
+//
+// Copyright(c) 2016-2018 Gabi Melman.
+// Distributed under the MIT License (http://opensource.org/licenses/MIT)
+//
+
+#pragma once
+
+//
+// Include a bundled header-only copy of fmtlib or an external one.
+// By default spdlog include its own copy.
+//
+#include <spdlog/tweakme.h>
+
+#if defined(SPDLOG_USE_STD_FORMAT)  // SPDLOG_USE_STD_FORMAT is defined - use std::format
+    #include <format>
+#elif !defined(SPDLOG_FMT_EXTERNAL)
+    #if !defined(SPDLOG_COMPILED_LIB) && !defined(FMT_HEADER_ONLY)
+        #define FMT_HEADER_ONLY
+    #endif
+    #ifndef FMT_USE_WINDOWS_H
+        #define FMT_USE_WINDOWS_H 0
+    #endif
+
+    #include <spdlog/fmt/bundled/core.h>
+    #include <spdlog/fmt/bundled/format.h>
+
+#else  // SPDLOG_FMT_EXTERNAL is defined - use external fmtlib
+    #include <fmt/core.h>
+    #include <fmt/format.h>
+#endif

spdlog/fmt/ostr.h

@@ -0,0 +1,23 @@
+//
+// Copyright(c) 2016 Gabi Melman.
+// Distributed under the MIT License (http://opensource.org/licenses/MIT)
+//
+
+#pragma once
+//
+// include bundled or external copy of fmtlib's ostream support
+//
+#include <spdlog/tweakme.h>
+
+#if !defined(SPDLOG_USE_STD_FORMAT)
+    #if !defined(SPDLOG_FMT_EXTERNAL)
+        #ifdef SPDLOG_HEADER_ONLY
+            #ifndef FMT_HEADER_ONLY
+                #define FMT_HEADER_ONLY
+            #endif
+        #endif
+        #include <spdlog/fmt/bundled/ostream.h>
+    #else
+        #include <fmt/ostream.h>
+    #endif
+#endif

spdlog/fmt/ranges.h

@@ -0,0 +1,23 @@
+//
+// Copyright(c) 2016 Gabi Melman.
+// Distributed under the MIT License (http://opensource.org/licenses/MIT)
+//
+
+#pragma once
+//
+// include bundled or external copy of fmtlib's ranges support
+//
+#include <spdlog/tweakme.h>
+
+#if !defined(SPDLOG_USE_STD_FORMAT)
+    #if !defined(SPDLOG_FMT_EXTERNAL)
+        #ifdef SPDLOG_HEADER_ONLY
+            #ifndef FMT_HEADER_ONLY
+                #define FMT_HEADER_ONLY
+            #endif
+        #endif
+        #include <spdlog/fmt/bundled/ranges.h>
+    #else
+        #include <fmt/ranges.h>
+    #endif
+#endif

spdlog/fmt/std.h

@@ -0,0 +1,24 @@
+//
+// Copyright(c) 2016 Gabi Melman.
+// Distributed under the MIT License (http://opensource.org/licenses/MIT)
+//
+
+#pragma once
+//
+// include bundled or external copy of fmtlib's std support (for formatting e.g.
+// std::filesystem::path, std::thread::id, std::monostate, std::variant, ...)
+//
+#include <spdlog/tweakme.h>
+
+#if !defined(SPDLOG_USE_STD_FORMAT)
+    #if !defined(SPDLOG_FMT_EXTERNAL)
+        #ifdef SPDLOG_HEADER_ONLY
+            #ifndef FMT_HEADER_ONLY
+                #define FMT_HEADER_ONLY
+            #endif
+        #endif
+        #include <spdlog/fmt/bundled/std.h>
+    #else
+        #include <fmt/std.h>
+    #endif
+#endif

spdlog/fmt/xchar.h

@@ -0,0 +1,23 @@
+//
+// Copyright(c) 2016 Gabi Melman.
+// Distributed under the MIT License (http://opensource.org/licenses/MIT)
+//
+
+#pragma once
+//
+// include bundled or external copy of fmtlib's xchar support
+//
+#include <spdlog/tweakme.h>
+
+#if !defined(SPDLOG_USE_STD_FORMAT)
+    #if !defined(SPDLOG_FMT_EXTERNAL)
+        #ifdef SPDLOG_HEADER_ONLY
+            #ifndef FMT_HEADER_ONLY
+                #define FMT_HEADER_ONLY
+            #endif
+        #endif
+        #include <spdlog/fmt/bundled/xchar.h>
+    #else
+        #include <fmt/xchar.h>
+    #endif
+#endif

spdlog/formatter.h

@@ -0,0 +1,17 @@
+// Copyright(c) 2015-present, Gabi Melman & spdlog contributors.
+// Distributed under the MIT License (http://opensource.org/licenses/MIT)
+
+#pragma once
+
+#include <spdlog/details/log_msg.h>
+#include <spdlog/fmt/fmt.h>
+
+namespace spdlog {
+
+class formatter {
+public:
+    virtual ~formatter() = default;
+    virtual void format(const details::log_msg &msg, memory_buf_t &dest) = 0;
+    virtual std::unique_ptr<formatter> clone() const = 0;
+};
+}  // namespace spdlog

spdlog/fwd.h

@@ -0,0 +1,18 @@
+// Copyright(c) 2015-present, Gabi Melman & spdlog contributors.
+// Distributed under the MIT License (http://opensource.org/licenses/MIT)
+
+#pragma once
+
+namespace spdlog {
+class logger;
+class formatter;
+
+namespace sinks {
+class sink;
+}
+
+namespace level {
+enum level_enum : int;
+}
+
+}  // namespace spdlog

spdlog/logger-inl.h

@@ -0,0 +1,198 @@
+// Copyright(c) 2015-present, Gabi Melman & spdlog contributors.
+// Distributed under the MIT License (http://opensource.org/licenses/MIT)
+
+#pragma once
+
+#ifndef SPDLOG_HEADER_ONLY
+    #include <spdlog/logger.h>
+#endif
+
+#include <spdlog/details/backtracer.h>
+#include <spdlog/pattern_formatter.h>
+#include <spdlog/sinks/sink.h>
+
+#include <cstdio>
+
+namespace spdlog {
+
+// public methods
+SPDLOG_INLINE logger::logger(const logger &other)
+    : name_(other.name_),
+      sinks_(other.sinks_),
+      level_(other.level_.load(std::memory_order_relaxed)),
+      flush_level_(other.flush_level_.load(std::memory_order_relaxed)),
+      custom_err_handler_(other.custom_err_handler_),
+      tracer_(other.tracer_) {}
+
+SPDLOG_INLINE logger::logger(logger &&other) SPDLOG_NOEXCEPT
+    : name_(std::move(other.name_)),
+      sinks_(std::move(other.sinks_)),
+      level_(other.level_.load(std::memory_order_relaxed)),
+      flush_level_(other.flush_level_.load(std::memory_order_relaxed)),
+      custom_err_handler_(std::move(other.custom_err_handler_)),
+      tracer_(std::move(other.tracer_))
+
+{}
+
+SPDLOG_INLINE logger &logger::operator=(logger other) SPDLOG_NOEXCEPT {
+    this->swap(other);
+    return *this;
+}
+
+SPDLOG_INLINE void logger::swap(spdlog::logger &other) SPDLOG_NOEXCEPT {
+    name_.swap(other.name_);
+    sinks_.swap(other.sinks_);
+
+    // swap level_
+    auto other_level = other.level_.load();
+    auto my_level = level_.exchange(other_level);
+    other.level_.store(my_level);
+
+    // swap flush level_
+    other_level = other.flush_level_.load();
+    my_level = flush_level_.exchange(other_level);
+    other.flush_level_.store(my_level);
+
+    custom_err_handler_.swap(other.custom_err_handler_);
+    std::swap(tracer_, other.tracer_);
+}
+
+SPDLOG_INLINE void swap(logger &a, logger &b) { a.swap(b); }
+
+SPDLOG_INLINE void logger::set_level(level::level_enum log_level) { level_.store(log_level); }
+
+SPDLOG_INLINE level::level_enum logger::level() const {
+    return static_cast<level::level_enum>(level_.load(std::memory_order_relaxed));
+}
+
+SPDLOG_INLINE const std::string &logger::name() const { return name_; }
+
+// set formatting for the sinks in this logger.
+// each sink will get a separate instance of the formatter object.
+SPDLOG_INLINE void logger::set_formatter(std::unique_ptr<formatter> f) {
+    for (auto it = sinks_.begin(); it != sinks_.end(); ++it) {
+        if (std::next(it) == sinks_.end()) {
+            // last element - we can be move it.
+            (*it)->set_formatter(std::move(f));
+            break;  // to prevent clang-tidy warning
+        } else {
+            (*it)->set_formatter(f->clone());
+        }
+    }
+}
+
+SPDLOG_INLINE void logger::set_pattern(std::string pattern, pattern_time_type time_type) {
+    auto new_formatter = details::make_unique<pattern_formatter>(std::move(pattern), time_type);
+    set_formatter(std::move(new_formatter));
+}
+
+// create new backtrace sink and move to it all our child sinks
+SPDLOG_INLINE void logger::enable_backtrace(size_t n_messages) { tracer_.enable(n_messages); }
+
+// restore orig sinks and level and delete the backtrace sink
+SPDLOG_INLINE void logger::disable_backtrace() { tracer_.disable(); }
+
+SPDLOG_INLINE void logger::dump_backtrace() { dump_backtrace_(); }
+
+// flush functions
+SPDLOG_INLINE void logger::flush() { flush_(); }
+
+SPDLOG_INLINE void logger::flush_on(level::level_enum log_level) { flush_level_.store(log_level); }
+
+SPDLOG_INLINE level::level_enum logger::flush_level() const {
+    return static_cast<level::level_enum>(flush_level_.load(std::memory_order_relaxed));
+}
+
+// sinks
+SPDLOG_INLINE const std::vector<sink_ptr> &logger::sinks() const { return sinks_; }
+
+SPDLOG_INLINE std::vector<sink_ptr> &logger::sinks() { return sinks_; }
+
+// error handler
+SPDLOG_INLINE void logger::set_error_handler(err_handler handler) {
+    custom_err_handler_ = std::move(handler);
+}
+
+// create new logger with same sinks and configuration.
+SPDLOG_INLINE std::shared_ptr<logger> logger::clone(std::string logger_name) {
+    auto cloned = std::make_shared<logger>(*this);
+    cloned->name_ = std::move(logger_name);
+    return cloned;
+}
+
+// protected methods
+SPDLOG_INLINE void logger::log_it_(const spdlog::details::log_msg &log_msg,
+                                   bool log_enabled,
+                                   bool traceback_enabled) {
+    if (log_enabled) {
+        sink_it_(log_msg);
+    }
+    if (traceback_enabled) {
+        tracer_.push_back(log_msg);
+    }
+}
+
+SPDLOG_INLINE void logger::sink_it_(const details::log_msg &msg) {
+    for (auto &sink : sinks_) {
+        if (sink->should_log(msg.level)) {
+            SPDLOG_TRY { sink->log(msg); }
+            SPDLOG_LOGGER_CATCH(msg.source)
+        }
+    }
+
+    if (should_flush_(msg)) {
+        flush_();
+    }
+}
+
+SPDLOG_INLINE void logger::flush_() {
+    for (auto &sink : sinks_) {
+        SPDLOG_TRY { sink->flush(); }
+        SPDLOG_LOGGER_CATCH(source_loc())
+    }
+}
+
+SPDLOG_INLINE void logger::dump_backtrace_() {
+    using details::log_msg;
+    if (tracer_.enabled() && !tracer_.empty()) {
+        sink_it_(
+            log_msg{name(), level::info, "****************** Backtrace Start ******************"});
+        tracer_.foreach_pop([this](const log_msg &msg) { this->sink_it_(msg); });
+        sink_it_(
+            log_msg{name(), level::info, "****************** Backtrace End ********************"});
+    }
+}
+
+SPDLOG_INLINE bool logger::should_flush_(const details::log_msg &msg) {
+    auto flush_level = flush_level_.load(std::memory_order_relaxed);
+    return (msg.level >= flush_level) && (msg.level != level::off);
+}
+
+SPDLOG_INLINE void logger::err_handler_(const std::string &msg) {
+    if (custom_err_handler_) {
+        custom_err_handler_(msg);
+    } else {
+        using std::chrono::system_clock;
+        static std::mutex mutex;
+        static std::chrono::system_clock::time_point last_report_time;
+        static size_t err_counter = 0;
+        std::lock_guard<std::mutex> lk{mutex};
+        auto now = system_clock::now();
+        err_counter++;
+        if (now - last_report_time < std::chrono::seconds(1)) {
+            return;
+        }
+        last_report_time = now;
+        auto tm_time = details::os::localtime(system_clock::to_time_t(now));
+        char date_buf[64];
+        std::strftime(date_buf, sizeof(date_buf), "%Y-%m-%d %H:%M:%S", &tm_time);
+#if defined(USING_R) && defined(R_R_H)  // if in R environment
+        REprintf("[*** LOG ERROR #%04zu ***] [%s] [%s] %s\n", err_counter, date_buf, name().c_str(),
+                 msg.c_str());
+#else
+        std::fprintf(stderr, "[*** LOG ERROR #%04zu ***] [%s] [%s] %s\n", err_counter, date_buf,
+                     name().c_str(), msg.c_str());
+#endif
+    }
+}
+}  // namespace spdlog

spdlog/logger.h

@@ -0,0 +1,379 @@
+// Copyright(c) 2015-present, Gabi Melman & spdlog contributors.
+// Distributed under the MIT License (http://opensource.org/licenses/MIT)
+
+#pragma once
+
+// Thread safe logger (except for set_error_handler())
+// Has name, log level, vector of std::shared sink pointers and formatter
+// Upon each log write the logger:
+// 1. Checks if its log level is enough to log the message and if yes:
+// 2. Call the underlying sinks to do the job.
+// 3. Each sink use its own private copy of a formatter to format the message
+// and send to its destination.
+//
+// The use of private formatter per sink provides the opportunity to cache some
+// formatted data, and support for different format per sink.
+
+#include <spdlog/common.h>
+#include <spdlog/details/backtracer.h>
+#include <spdlog/details/log_msg.h>
+
+#ifdef SPDLOG_WCHAR_TO_UTF8_SUPPORT
+    #ifndef _WIN32
+        #error SPDLOG_WCHAR_TO_UTF8_SUPPORT only supported on windows
+    #endif
+    #include <spdlog/details/os.h>
+#endif
+
+#include <vector>
+
+#ifndef SPDLOG_NO_EXCEPTIONS
+    #define SPDLOG_LOGGER_CATCH(location)                                                 \
+        catch (const std::exception &ex) {                                                \
+            if (location.filename) {                                                      \
+                err_handler_(fmt_lib::format(SPDLOG_FMT_STRING("{} [{}({})]"), ex.what(), \
+                                             location.filename, location.line));          \
+            } else {                                                                      \
+                err_handler_(ex.what());                                                  \
+            }                                                                             \
+        }                                                                                 \
+        catch (...) {                                                                     \
+            err_handler_("Rethrowing unknown exception in logger");                       \
+            throw;                                                                        \
+        }
+#else
+    #define SPDLOG_LOGGER_CATCH(location)
+#endif
+
+namespace spdlog {
+
+class SPDLOG_API logger {
+public:
+    // Empty logger
+    explicit logger(std::string name)
+        : name_(std::move(name)),
+          sinks_() {}
+
+    // Logger with range on sinks
+    template <typename It>
+    logger(std::string name, It begin, It end)
+        : name_(std::move(name)),
+          sinks_(begin, end) {}
+
+    // Logger with single sink
+    logger(std::string name, sink_ptr single_sink)
+        : logger(std::move(name), {std::move(single_sink)}) {}
+
+    // Logger with sinks init list
+    logger(std::string name, sinks_init_list sinks)
+        : logger(std::move(name), sinks.begin(), sinks.end()) {}
+
+    virtual ~logger() = default;
+
+    logger(const logger &other);
+    logger(logger &&other) SPDLOG_NOEXCEPT;
+    logger &operator=(logger other) SPDLOG_NOEXCEPT;
+    void swap(spdlog::logger &other) SPDLOG_NOEXCEPT;
+
+    template <typename... Args>
+    void log(source_loc loc, level::level_enum lvl, format_string_t<Args...> fmt, Args &&...args) {
+        log_(loc, lvl, details::to_string_view(fmt), std::forward<Args>(args)...);
+    }
+
+    template <typename... Args>
+    void log(level::level_enum lvl, format_string_t<Args...> fmt, Args &&...args) {
+        log(source_loc{}, lvl, fmt, std::forward<Args>(args)...);
+    }
+
+    template <typename T>
+    void log(level::level_enum lvl, const T &msg) {
+        log(source_loc{}, lvl, msg);
+    }
+
+    // T cannot be statically converted to format string (including string_view/wstring_view)
+    template <class T,
+              typename std::enable_if<!is_convertible_to_any_format_string<const T &>::value,
+                                      int>::type = 0>
+    void log(source_loc loc, level::level_enum lvl, const T &msg) {
+        log(loc, lvl, "{}", msg);
+    }
+
+    void log(log_clock::time_point log_time,
+             source_loc loc,
+             level::level_enum lvl,
+             string_view_t msg) {
+        bool log_enabled = should_log(lvl);
+        bool traceback_enabled = tracer_.enabled();
+        if (!log_enabled && !traceback_enabled) {
+            return;
+        }
+
+        details::log_msg log_msg(log_time, loc, name_, lvl, msg);
+        log_it_(log_msg, log_enabled, traceback_enabled);
+    }
+
+    void log(source_loc loc, level::level_enum lvl, string_view_t msg) {
+        bool log_enabled = should_log(lvl);
+        bool traceback_enabled = tracer_.enabled();
+        if (!log_enabled && !traceback_enabled) {
+            return;
+        }
+
+        details::log_msg log_msg(loc, name_, lvl, msg);
+        log_it_(log_msg, log_enabled, traceback_enabled);
+    }
+
+    void log(level::level_enum lvl, string_view_t msg) { log(source_loc{}, lvl, msg); }
+
+    template <typename... Args>
+    void trace(format_string_t<Args...> fmt, Args &&...args) {
+        log(level::trace, fmt, std::forward<Args>(args)...);
+    }
+
+    template <typename... Args>
+    void debug(format_string_t<Args...> fmt, Args &&...args) {
+        log(level::debug, fmt, std::forward<Args>(args)...);
+    }
+
+    template <typename... Args>
+    void info(format_string_t<Args...> fmt, Args &&...args) {
+        log(level::info, fmt, std::forward<Args>(args)...);
+    }
+
+    template <typename... Args>
+    void warn(format_string_t<Args...> fmt, Args &&...args) {
+        log(level::warn, fmt, std::forward<Args>(args)...);
+    }
+
+    template <typename... Args>
+    void error(format_string_t<Args...> fmt, Args &&...args) {
+        log(level::err, fmt, std::forward<Args>(args)...);
+    }
+
+    template <typename... Args>
+    void critical(format_string_t<Args...> fmt, Args &&...args) {
+        log(level::critical, fmt, std::forward<Args>(args)...);
+    }
+
+#ifdef SPDLOG_WCHAR_TO_UTF8_SUPPORT
+    template <typename... Args>
+    void log(source_loc loc, level::level_enum lvl, wformat_string_t<Args...> fmt, Args &&...args) {
+        log_(loc, lvl, details::to_string_view(fmt), std::forward<Args>(args)...);
+    }
+
+    template <typename... Args>
+    void log(level::level_enum lvl, wformat_string_t<Args...> fmt, Args &&...args) {
+        log(source_loc{}, lvl, fmt, std::forward<Args>(args)...);
+    }
+
+    void log(log_clock::time_point log_time,
+             source_loc loc,
+             level::level_enum lvl,
+             wstring_view_t msg) {
+        bool log_enabled = should_log(lvl);
+        bool traceback_enabled = tracer_.enabled();
+        if (!log_enabled && !traceback_enabled) {
+            return;
+        }
+
+        memory_buf_t buf;
+        details::os::wstr_to_utf8buf(wstring_view_t(msg.data(), msg.size()), buf);
+        details::log_msg log_msg(log_time, loc, name_, lvl, string_view_t(buf.data(), buf.size()));
+        log_it_(log_msg, log_enabled, traceback_enabled);
+    }
+
+    void log(source_loc loc, level::level_enum lvl, wstring_view_t msg) {
+        bool log_enabled = should_log(lvl);
+        bool traceback_enabled = tracer_.enabled();
+        if (!log_enabled && !traceback_enabled) {
+            return;
+        }
+
+        memory_buf_t buf;
+        details::os::wstr_to_utf8buf(wstring_view_t(msg.data(), msg.size()), buf);
+        details::log_msg log_msg(loc, name_, lvl, string_view_t(buf.data(), buf.size()));
+        log_it_(log_msg, log_enabled, traceback_enabled);
+    }
+
+    void log(level::level_enum lvl, wstring_view_t msg) { log(source_loc{}, lvl, msg); }
+
+    template <typename... Args>
+    void trace(wformat_string_t<Args...> fmt, Args &&...args) {
+        log(level::trace, fmt, std::forward<Args>(args)...);
+    }
+
+    template <typename... Args>
+    void debug(wformat_string_t<Args...> fmt, Args &&...args) {
+        log(level::debug, fmt, std::forward<Args>(args)...);
+    }
+
+    template <typename... Args>
+    void info(wformat_string_t<Args...> fmt, Args &&...args) {
+        log(level::info, fmt, std::forward<Args>(args)...);
+    }
+
+    template <typename... Args>
+    void warn(wformat_string_t<Args...> fmt, Args &&...args) {
+        log(level::warn, fmt, std::forward<Args>(args)...);
+    }
+
+    template <typename... Args>
+    void error(wformat_string_t<Args...> fmt, Args &&...args) {
+        log(level::err, fmt, std::forward<Args>(args)...);
+    }
+
+    template <typename... Args>
+    void critical(wformat_string_t<Args...> fmt, Args &&...args) {
+        log(level::critical, fmt, std::forward<Args>(args)...);
+    }
+#endif
+
+    template <typename T>
+    void trace(const T &msg) {
+        log(level::trace, msg);
+    }
+
+    template <typename T>
+    void debug(const T &msg) {
+        log(level::debug, msg);
+    }
+
+    template <typename T>
+    void info(const T &msg) {
+        log(level::info, msg);
+    }
+
+    template <typename T>
+    void warn(const T &msg) {
+        log(level::warn, msg);
+    }
+
+    template <typename T>
+    void error(const T &msg) {
+        log(level::err, msg);
+    }
+
+    template <typename T>
+    void critical(const T &msg) {
+        log(level::critical, msg);
+    }
+
+    // return true logging is enabled for the given level.
+    bool should_log(level::level_enum msg_level) const {
+        return msg_level >= level_.load(std::memory_order_relaxed);
+    }
+
+    // return true if backtrace logging is enabled.
+    bool should_backtrace() const { return tracer_.enabled(); }
+
+    void set_level(level::level_enum log_level);
+
+    level::level_enum level() const;
+
+    const std::string &name() const;
+
+    // set formatting for the sinks in this logger.
+    // each sink will get a separate instance of the formatter object.
+    void set_formatter(std::unique_ptr<formatter> f);
+
+    // set formatting for the sinks in this logger.
+    // equivalent to
+    //     set_formatter(make_unique<pattern_formatter>(pattern, time_type))
+    // Note: each sink will get a new instance of a formatter object, replacing the old one.
+    void set_pattern(std::string pattern, pattern_time_type time_type = pattern_time_type::local);
+
+    // backtrace support.
+    // efficiently store all debug/trace messages in a circular buffer until needed for debugging.
+    void enable_backtrace(size_t n_messages);
+    void disable_backtrace();
+    void dump_backtrace();
+
+    // flush functions
+    void flush();
+    void flush_on(level::level_enum log_level);
+    level::level_enum flush_level() const;
+
+    // sinks
+    const std::vector<sink_ptr> &sinks() const;
+
+    std::vector<sink_ptr> &sinks();
+
+    // error handler
+    void set_error_handler(err_handler);
+
+    // create new logger with same sinks and configuration.
+    virtual std::shared_ptr<logger> clone(std::string logger_name);
+
+protected:
+    std::string name_;
+    std::vector<sink_ptr> sinks_;
+    spdlog::level_t level_{level::info};
+    spdlog::level_t flush_level_{level::off};
+    err_handler custom_err_handler_{nullptr};
+    details::backtracer tracer_;
+
+    // common implementation for after templated public api has been resolved
+    template <typename... Args>
+    void log_(source_loc loc, level::level_enum lvl, string_view_t fmt, Args &&...args) {
+        bool log_enabled = should_log(lvl);
+        bool traceback_enabled = tracer_.enabled();
+        if (!log_enabled && !traceback_enabled) {
+            return;
+        }
+        SPDLOG_TRY {
+            memory_buf_t buf;
+#ifdef SPDLOG_USE_STD_FORMAT
+            fmt_lib::vformat_to(std::back_inserter(buf), fmt, fmt_lib::make_format_args(args...));
+#else
+            fmt::vformat_to(fmt::appender(buf), fmt, fmt::make_format_args(args...));
+#endif
+
+            details::log_msg log_msg(loc, name_, lvl, string_view_t(buf.data(), buf.size()));
+            log_it_(log_msg, log_enabled, traceback_enabled);
+        }
+        SPDLOG_LOGGER_CATCH(loc)
+    }
+
+#ifdef SPDLOG_WCHAR_TO_UTF8_SUPPORT
+    template <typename... Args>
+    void log_(source_loc loc, level::level_enum lvl, wstring_view_t fmt, Args &&...args) {
+        bool log_enabled = should_log(lvl);
+        bool traceback_enabled = tracer_.enabled();
+        if (!log_enabled && !traceback_enabled) {
+            return;
+        }
+        SPDLOG_TRY {
+            // format to wmemory_buffer and convert to utf8
+            wmemory_buf_t wbuf;
+            fmt_lib::vformat_to(std::back_inserter(wbuf), fmt,
+                                fmt_lib::make_format_args<fmt_lib::wformat_context>(args...));
+
+            memory_buf_t buf;
+            details::os::wstr_to_utf8buf(wstring_view_t(wbuf.data(), wbuf.size()), buf);
+            details::log_msg log_msg(loc, name_, lvl, string_view_t(buf.data(), buf.size()));
+            log_it_(log_msg, log_enabled, traceback_enabled);
+        }
+        SPDLOG_LOGGER_CATCH(loc)
+    }
+#endif  // SPDLOG_WCHAR_TO_UTF8_SUPPORT
+
+    // log the given message (if the given log level is high enough),
+    // and save backtrace (if backtrace is enabled).
+    void log_it_(const details::log_msg &log_msg, bool log_enabled, bool traceback_enabled);
+    virtual void sink_it_(const details::log_msg &msg);
+    virtual void flush_();
+    void dump_backtrace_();
+    bool should_flush_(const details::log_msg &msg);
+
+    // handle errors during logging.
+    // default handler prints the error to stderr at max rate of 1 message/sec.
+    void err_handler_(const std::string &msg);
+};
+
+void swap(logger &a, logger &b);
+
+}  // namespace spdlog
+
+#ifdef SPDLOG_HEADER_ONLY
+    #include "logger-inl.h"
+#endif

spdlog/mdc.h

@@ -0,0 +1,50 @@
+// Copyright(c) 2015-present, Gabi Melman & spdlog contributors.
+// Distributed under the MIT License (http://opensource.org/licenses/MIT)
+
+#pragma once
+
+#if defined(SPDLOG_NO_TLS)
+    #error "This header requires thread local storage support, but SPDLOG_NO_TLS is defined."
+#endif
+
+#include <map>
+#include <string>
+
+#include <spdlog/common.h>
+
+// MDC is a simple map of key->string values stored in thread local storage whose content will be printed by the loggers.
+// Note: Not supported in async mode (thread local storage - so the async thread pool have different copy).
+//
+// Usage example:
+// spdlog::mdc::put("mdc_key_1", "mdc_value_1");
+// spdlog::info("Hello, {}", "World!");  // => [2024-04-26 02:08:05.040] [info] [mdc_key_1:mdc_value_1] Hello, World!
+
+namespace spdlog {
+class SPDLOG_API mdc {
+public:
+    using mdc_map_t = std::map<std::string, std::string>;
+
+    static void put(const std::string &key, const std::string &value) {
+        get_context()[key] = value;
+    }
+
+    static std::string get(const std::string &key) {
+        auto &context = get_context();
+        auto it = context.find(key);
+        if (it != context.end()) {
+            return it->second;
+        }
+        return "";
+    }
+
+    static void remove(const std::string &key) { get_context().erase(key); }
+
+    static void clear() { get_context().clear(); }
+
+    static mdc_map_t &get_context() {
+        static thread_local mdc_map_t context;
+        return context;
+    }
+};
+
+}  // namespace spdlog

spdlog/pattern_formatter.h

@@ -0,0 +1,118 @@
+// Copyright(c) 2015-present, Gabi Melman & spdlog contributors.
+// Distributed under the MIT License (http://opensource.org/licenses/MIT)
+
+#pragma once
+
+#include <spdlog/common.h>
+#include <spdlog/details/log_msg.h>
+#include <spdlog/details/os.h>
+#include <spdlog/formatter.h>
+
+#include <chrono>
+#include <ctime>
+#include <memory>
+
+#include <string>
+#include <unordered_map>
+#include <vector>
+
+namespace spdlog {
+namespace details {
+
+// padding information.
+struct padding_info {
+    enum class pad_side { left, right, center };
+
+    padding_info() = default;
+    padding_info(size_t width, padding_info::pad_side side, bool truncate)
+        : width_(width),
+          side_(side),
+          truncate_(truncate),
+          enabled_(true) {}
+
+    bool enabled() const { return enabled_; }
+    size_t width_ = 0;
+    pad_side side_ = pad_side::left;
+    bool truncate_ = false;
+    bool enabled_ = false;
+};
+
+class SPDLOG_API flag_formatter {
+public:
+    explicit flag_formatter(padding_info padinfo)
+        : padinfo_(padinfo) {}
+    flag_formatter() = default;
+    virtual ~flag_formatter() = default;
+    virtual void format(const details::log_msg &msg,
+                        const std::tm &tm_time,
+                        memory_buf_t &dest) = 0;
+
+protected:
+    padding_info padinfo_;
+};
+
+}  // namespace details
+
+class SPDLOG_API custom_flag_formatter : public details::flag_formatter {
+public:
+    virtual std::unique_ptr<custom_flag_formatter> clone() const = 0;
+
+    void set_padding_info(const details::padding_info &padding) {
+        flag_formatter::padinfo_ = padding;
+    }
+};
+
+class SPDLOG_API pattern_formatter final : public formatter {
+public:
+    using custom_flags = std::unordered_map<char, std::unique_ptr<custom_flag_formatter>>;
+
+    explicit pattern_formatter(std::string pattern,
+                               pattern_time_type time_type = pattern_time_type::local,
+                               std::string eol = spdlog::details::os::default_eol,
+                               custom_flags custom_user_flags = custom_flags());
+
+    // use default pattern is not given
+    explicit pattern_formatter(pattern_time_type time_type = pattern_time_type::local,
+                               std::string eol = spdlog::details::os::default_eol);
+
+    pattern_formatter(const pattern_formatter &other) = delete;
+    pattern_formatter &operator=(const pattern_formatter &other) = delete;
+
+    std::unique_ptr<formatter> clone() const override;
+    void format(const details::log_msg &msg, memory_buf_t &dest) override;
+
+    template <typename T, typename... Args>
+    pattern_formatter &add_flag(char flag, Args &&...args) {
+        custom_handlers_[flag] = details::make_unique<T>(std::forward<Args>(args)...);
+        return *this;
+    }
+    void set_pattern(std::string pattern);
+    void need_localtime(bool need = true);
+
+private:
+    std::string pattern_;
+    std::string eol_;
+    pattern_time_type pattern_time_type_;
+    bool need_localtime_;
+    std::tm cached_tm_;
+    std::chrono::seconds last_log_secs_;
+    std::vector<std::unique_ptr<details::flag_formatter>> formatters_;
+    custom_flags custom_handlers_;
+
+    std::tm get_time_(const details::log_msg &msg);
+    template <typename Padder>
+    void handle_flag_(char flag, details::padding_info padding);
+
+    // Extract given pad spec (e.g. %8X)
+    // Advance the given it pass the end of the padding spec found (if any)
+    // Return padding.
+    static details::padding_info handle_padspec_(std::string::const_iterator &it,
+                                                 std::string::const_iterator end);
+
+    void compile_pattern_(const std::string &pattern);
+};
+}  // namespace spdlog
+
+#ifdef SPDLOG_HEADER_ONLY
+    #include "pattern_formatter-inl.h"
+#endif

spdlog/sinks/android_sink.h

@@ -0,0 +1,137 @@
+// Copyright(c) 2015-present, Gabi Melman & spdlog contributors.
+// Distributed under the MIT License (http://opensource.org/licenses/MIT)
+
+#pragma once
+
+#ifdef __ANDROID__
+
+    #include <spdlog/details/fmt_helper.h>
+    #include <spdlog/details/null_mutex.h>
+    #include <spdlog/details/os.h>
+    #include <spdlog/details/synchronous_factory.h>
+    #include <spdlog/sinks/base_sink.h>
+
+    #include <android/log.h>
+    #include <chrono>
+    #include <mutex>
+    #include <string>
+    #include <thread>
+    #include <type_traits>
+
+    #if !defined(SPDLOG_ANDROID_RETRIES)
+        #define SPDLOG_ANDROID_RETRIES 2
+    #endif
+
+namespace spdlog {
+namespace sinks {
+
+/*
+ * Android sink
+ * (logging using __android_log_write or __android_log_buf_write depending on the specified
+ * BufferID)
+ */
+template <typename Mutex, int BufferID = log_id::LOG_ID_MAIN>
+class android_sink final : public base_sink<Mutex> {
+public:
+    explicit android_sink(std::string tag = "spdlog", bool use_raw_msg = false)
+        : tag_(std::move(tag)),
+          use_raw_msg_(use_raw_msg) {}
+
+protected:
+    void sink_it_(const details::log_msg &msg) override {
+        const android_LogPriority priority = convert_to_android_(msg.level);
+        memory_buf_t formatted;
+        if (use_raw_msg_) {
+            details::fmt_helper::append_string_view(msg.payload, formatted);
+        } else {
+            base_sink<Mutex>::formatter_->format(msg, formatted);
+        }
+        formatted.push_back('\0');
+        const char *msg_output = formatted.data();
+
+        // See system/core/liblog/logger_write.c for explanation of return value
+        int ret = android_log(priority, tag_.c_str(), msg_output);
+        if (ret == -EPERM) {
+            return;  // !__android_log_is_loggable
+        }
+        int retry_count = 0;
+        while ((ret == -11 /*EAGAIN*/) && (retry_count < SPDLOG_ANDROID_RETRIES)) {
+            details::os::sleep_for_millis(5);
+            ret = android_log(priority, tag_.c_str(), msg_output);
+            retry_count++;
+        }
+
+        if (ret < 0) {
+            throw_spdlog_ex("logging to Android failed", ret);
+        }
+    }
+
+    void flush_() override {}
+
+private:
+    // There might be liblog versions used, that do not support __android_log_buf_write. So we only
+    // compile and link against
+    // __android_log_buf_write, if user explicitly provides a non-default log buffer. Otherwise,
+    // when using the default log buffer, always log via __android_log_write.
+    template <int ID = BufferID>
+    typename std::enable_if<ID == static_cast<int>(log_id::LOG_ID_MAIN), int>::type android_log(
+        int prio, const char *tag, const char *text) {
+        return __android_log_write(prio, tag, text);
+    }
+
+    template <int ID = BufferID>
+    typename std::enable_if<ID != static_cast<int>(log_id::LOG_ID_MAIN), int>::type android_log(
+        int prio, const char *tag, const char *text) {
+        return __android_log_buf_write(ID, prio, tag, text);
+    }
+
+    static android_LogPriority convert_to_android_(spdlog::level::level_enum level) {
+        switch (level) {
+            case spdlog::level::trace:
+                return ANDROID_LOG_VERBOSE;
+            case spdlog::level::debug:
+                return ANDROID_LOG_DEBUG;
+            case spdlog::level::info:
+                return ANDROID_LOG_INFO;
+            case spdlog::level::warn:
+                return ANDROID_LOG_WARN;
+            case spdlog::level::err:
+                return ANDROID_LOG_ERROR;
+            case spdlog::level::critical:
+                return ANDROID_LOG_FATAL;
+            default:
+                return ANDROID_LOG_DEFAULT;
+        }
+    }
+
+    std::string tag_;
+    bool use_raw_msg_;
+};
+
+using android_sink_mt = android_sink<std::mutex>;
+using android_sink_st = android_sink<details::null_mutex>;
+
+template <int BufferId = log_id::LOG_ID_MAIN>
+using android_sink_buf_mt = android_sink<std::mutex, BufferId>;
+template <int BufferId = log_id::LOG_ID_MAIN>
+using android_sink_buf_st = android_sink<details::null_mutex, BufferId>;
+
+}  // namespace sinks
+
+// Create and register android syslog logger
+
+template <typename Factory = spdlog::synchronous_factory>
+inline std::shared_ptr<logger> android_logger_mt(const std::string &logger_name,
+                                                 const std::string &tag = "spdlog") {
+    return Factory::template create<sinks::android_sink_mt>(logger_name, tag);
+}
+
+template <typename Factory = spdlog::synchronous_factory>
+inline std::shared_ptr<logger> android_logger_st(const std::string &logger_name,
+                                                 const std::string &tag = "spdlog") {
+    return Factory::template create<sinks::android_sink_st>(logger_name, tag);
+}
+
+}  // namespace spdlog
+
+#endif  // __ANDROID__

spdlog/sinks/ansicolor_sink-inl.h

@@ -0,0 +1,141 @@
+// Copyright(c) 2015-present, Gabi Melman & spdlog contributors.
+// Distributed under the MIT License (http://opensource.org/licenses/MIT)
+
+#pragma once
+
+#ifndef SPDLOG_HEADER_ONLY
+    #include <spdlog/sinks/ansicolor_sink.h>
+#endif
+
+#include <spdlog/details/os.h>
+#include <spdlog/pattern_formatter.h>
+
+namespace spdlog {
+namespace sinks {
+
+template <typename ConsoleMutex>
+SPDLOG_INLINE ansicolor_sink<ConsoleMutex>::ansicolor_sink(FILE *target_file, color_mode mode)
+    : target_file_(target_file),
+      mutex_(ConsoleMutex::mutex()),
+      formatter_(details::make_unique<spdlog::pattern_formatter>())
+
+{
+    set_color_mode_(mode);
+    colors_.at(level::trace) = to_string_(white);
+    colors_.at(level::debug) = to_string_(cyan);
+    colors_.at(level::info) = to_string_(green);
+    colors_.at(level::warn) = to_string_(yellow_bold);
+    colors_.at(level::err) = to_string_(red_bold);
+    colors_.at(level::critical) = to_string_(bold_on_red);
+    colors_.at(level::off) = to_string_(reset);
+}
+
+template <typename ConsoleMutex>
+SPDLOG_INLINE void ansicolor_sink<ConsoleMutex>::set_color(level::level_enum color_level,
+                                                           string_view_t color) {
+    std::lock_guard<mutex_t> lock(mutex_);
+    colors_.at(static_cast<size_t>(color_level)) = to_string_(color);
+}
+
+template <typename ConsoleMutex>
+SPDLOG_INLINE void ansicolor_sink<ConsoleMutex>::log(const details::log_msg &msg) {
+    // Wrap the originally formatted message in color codes.
+    // If color is not supported in the terminal, log as is instead.
+    std::lock_guard<mutex_t> lock(mutex_);
+    msg.color_range_start = 0;
+    msg.color_range_end = 0;
+    memory_buf_t formatted;
+    formatter_->format(msg, formatted);
+    if (should_do_colors_ && msg.color_range_end > msg.color_range_start) {
+        // before color range
+        print_range_(formatted, 0, msg.color_range_start);
+        // in color range
+        print_ccode_(colors_.at(static_cast<size_t>(msg.level)));
+        print_range_(formatted, msg.color_range_start, msg.color_range_end);
+        print_ccode_(reset);
+        // after color range
+        print_range_(formatted, msg.color_range_end, formatted.size());
+    } else  // no color
+    {
+        print_range_(formatted, 0, formatted.size());
+    }
+    fflush(target_file_);
+}
+
+template <typename ConsoleMutex>
+SPDLOG_INLINE void ansicolor_sink<ConsoleMutex>::flush() {
+    std::lock_guard<mutex_t> lock(mutex_);
+    fflush(target_file_);
+}
+
+template <typename ConsoleMutex>
+SPDLOG_INLINE void ansicolor_sink<ConsoleMutex>::set_pattern(const std::string &pattern) {
+    std::lock_guard<mutex_t> lock(mutex_);
+    formatter_ = std::unique_ptr<spdlog::formatter>(new pattern_formatter(pattern));
+}
+
+template <typename ConsoleMutex>
+SPDLOG_INLINE void ansicolor_sink<ConsoleMutex>::set_formatter(
+    std::unique_ptr<spdlog::formatter> sink_formatter) {
+    std::lock_guard<mutex_t> lock(mutex_);
+    formatter_ = std::move(sink_formatter);
+}
+
+template <typename ConsoleMutex>
+SPDLOG_INLINE bool ansicolor_sink<ConsoleMutex>::should_color() const {
+    return should_do_colors_;
+}
+
+template <typename ConsoleMutex>
+SPDLOG_INLINE void ansicolor_sink<ConsoleMutex>::set_color_mode(color_mode mode) {
+    std::lock_guard<mutex_t> lock(mutex_);
+    set_color_mode_(mode);
+}
+
+template <typename ConsoleMutex>
+SPDLOG_INLINE void ansicolor_sink<ConsoleMutex>::set_color_mode_(color_mode mode) {
+    switch (mode) {
+        case color_mode::always:
+            should_do_colors_ = true;
+            return;
+        case color_mode::automatic:
+            should_do_colors_ =
+                details::os::in_terminal(target_file_) && details::os::is_color_terminal();
+            return;
+        case color_mode::never:
+            should_do_colors_ = false;
+            return;
+        default:
+            should_do_colors_ = false;
+    }
+}
+
+template <typename ConsoleMutex>
+SPDLOG_INLINE void ansicolor_sink<ConsoleMutex>::print_ccode_(const string_view_t &color_code) const {
+    details::os::fwrite_bytes(color_code.data(), color_code.size(), target_file_);
+}
+
+template <typename ConsoleMutex>
+SPDLOG_INLINE void ansicolor_sink<ConsoleMutex>::print_range_(const memory_buf_t &formatted,
+                                                              size_t start,
+                                                              size_t end) const {
+    details::os::fwrite_bytes(formatted.data() + start, end - start, target_file_);
+}
+
+template <typename ConsoleMutex>
+SPDLOG_INLINE std::string ansicolor_sink<ConsoleMutex>::to_string_(const string_view_t &sv) {
+    return std::string(sv.data(), sv.size());
+}
+
+// ansicolor_stdout_sink
+template <typename ConsoleMutex>
+SPDLOG_INLINE ansicolor_stdout_sink<ConsoleMutex>::ansicolor_stdout_sink(color_mode mode)
+    : ansicolor_sink<ConsoleMutex>(stdout, mode) {}
+
+// ansicolor_stderr_sink
+template <typename ConsoleMutex>
+SPDLOG_INLINE ansicolor_stderr_sink<ConsoleMutex>::ansicolor_stderr_sink(color_mode mode)
+    : ansicolor_sink<ConsoleMutex>(stderr, mode) {}
+
+}  // namespace sinks
+}  // namespace spdlog

spdlog/sinks/ansicolor_sink.h

@@ -0,0 +1,116 @@
+// Copyright(c) 2015-present, Gabi Melman & spdlog contributors.
+// Distributed under the MIT License (http://opensource.org/licenses/MIT)
+
+#pragma once
+
+#include <array>
+#include <memory>
+#include <mutex>
+#include <spdlog/details/console_globals.h>
+#include <spdlog/details/null_mutex.h>
+#include <spdlog/sinks/sink.h>
+#include <string>
+
+namespace spdlog {
+namespace sinks {
+
+/**
+ * This sink prefixes the output with an ANSI escape sequence color code
+ * depending on the severity
+ * of the message.
+ * If no color terminal detected, omit the escape codes.
+ */
+
+template <typename ConsoleMutex>
+class ansicolor_sink : public sink {
+public:
+    using mutex_t = typename ConsoleMutex::mutex_t;
+    ansicolor_sink(FILE *target_file, color_mode mode);
+    ~ansicolor_sink() override = default;
+
+    ansicolor_sink(const ansicolor_sink &other) = delete;
+    ansicolor_sink(ansicolor_sink &&other) = delete;
+
+    ansicolor_sink &operator=(const ansicolor_sink &other) = delete;
+    ansicolor_sink &operator=(ansicolor_sink &&other) = delete;
+
+    void set_color(level::level_enum color_level, string_view_t color);
+    void set_color_mode(color_mode mode);
+    bool should_color() const;
+
+    void log(const details::log_msg &msg) override;
+    void flush() override;
+    void set_pattern(const std::string &pattern) final override;
+    void set_formatter(std::unique_ptr<spdlog::formatter> sink_formatter) override;
+
+    // Formatting codes
+    const string_view_t reset = "\033[m";
+    const string_view_t bold = "\033[1m";
+    const string_view_t dark = "\033[2m";
+    const string_view_t underline = "\033[4m";
+    const string_view_t blink = "\033[5m";
+    const string_view_t reverse = "\033[7m";
+    const string_view_t concealed = "\033[8m";
+    const string_view_t clear_line = "\033[K";
+
+    // Foreground colors
+    const string_view_t black = "\033[30m";
+    const string_view_t red = "\033[31m";
+    const string_view_t green = "\033[32m";
+    const string_view_t yellow = "\033[33m";
+    const string_view_t blue = "\033[34m";
+    const string_view_t magenta = "\033[35m";
+    const string_view_t cyan = "\033[36m";
+    const string_view_t white = "\033[37m";
+
+    /// Background colors
+    const string_view_t on_black = "\033[40m";
+    const string_view_t on_red = "\033[41m";
+    const string_view_t on_green = "\033[42m";
+    const string_view_t on_yellow = "\033[43m";
+    const string_view_t on_blue = "\033[44m";
+    const string_view_t on_magenta = "\033[45m";
+    const string_view_t on_cyan = "\033[46m";
+    const string_view_t on_white = "\033[47m";
+
+    /// Bold colors
+    const string_view_t yellow_bold = "\033[33m\033[1m";
+    const string_view_t red_bold = "\033[31m\033[1m";
+    const string_view_t bold_on_red = "\033[1m\033[41m";
+
+private:
+    FILE *target_file_;
+    mutex_t &mutex_;
+    bool should_do_colors_;
+    std::unique_ptr<spdlog::formatter> formatter_;
+    std::array<std::string, level::n_levels> colors_;
+    void set_color_mode_(color_mode mode);
+    void print_ccode_(const string_view_t &color_code) const;
+    void print_range_(const memory_buf_t &formatted, size_t start, size_t end) const;
+    static std::string to_string_(const string_view_t &sv);
+};
+
+template <typename ConsoleMutex>
+class ansicolor_stdout_sink : public ansicolor_sink<ConsoleMutex> {
+public:
+    explicit ansicolor_stdout_sink(color_mode mode = color_mode::automatic);
+};
+
+template <typename ConsoleMutex>
+class ansicolor_stderr_sink : public ansicolor_sink<ConsoleMutex> {
+public:
+    explicit ansicolor_stderr_sink(color_mode mode = color_mode::automatic);
+};
+
+using ansicolor_stdout_sink_mt = ansicolor_stdout_sink<details::console_mutex>;
+using ansicolor_stdout_sink_st = ansicolor_stdout_sink<details::console_nullmutex>;
+
+using ansicolor_stderr_sink_mt = ansicolor_stderr_sink<details::console_mutex>;
+using ansicolor_stderr_sink_st = ansicolor_stderr_sink<details::console_nullmutex>;
+
+}  // namespace sinks
+}  // namespace spdlog
+
+#ifdef SPDLOG_HEADER_ONLY
+    #include "ansicolor_sink-inl.h"
+#endif

spdlog/sinks/base_sink-inl.h

@@ -0,0 +1,59 @@
+// Copyright(c) 2015-present, Gabi Melman & spdlog contributors.
+// Distributed under the MIT License (http://opensource.org/licenses/MIT)
+
+#pragma once
+
+#ifndef SPDLOG_HEADER_ONLY
+    #include <spdlog/sinks/base_sink.h>
+#endif
+
+#include <spdlog/common.h>
+#include <spdlog/pattern_formatter.h>
+
+#include <memory>
+#include <mutex>
+
+template <typename Mutex>
+SPDLOG_INLINE spdlog::sinks::base_sink<Mutex>::base_sink()
+    : formatter_{details::make_unique<spdlog::pattern_formatter>()} {}
+
+template <typename Mutex>
+SPDLOG_INLINE spdlog::sinks::base_sink<Mutex>::base_sink(
+    std::unique_ptr<spdlog::formatter> formatter)
+    : formatter_{std::move(formatter)} {}
+
+template <typename Mutex>
+void SPDLOG_INLINE spdlog::sinks::base_sink<Mutex>::log(const details::log_msg &msg) {
+    std::lock_guard<Mutex> lock(mutex_);
+    sink_it_(msg);
+}
+
+template <typename Mutex>
+void SPDLOG_INLINE spdlog::sinks::base_sink<Mutex>::flush() {
+    std::lock_guard<Mutex> lock(mutex_);
+    flush_();
+}
+
+template <typename Mutex>
+void SPDLOG_INLINE spdlog::sinks::base_sink<Mutex>::set_pattern(const std::string &pattern) {
+    std::lock_guard<Mutex> lock(mutex_);
+    set_pattern_(pattern);
+}
+
+template <typename Mutex>
+void SPDLOG_INLINE
+spdlog::sinks::base_sink<Mutex>::set_formatter(std::unique_ptr<spdlog::formatter> sink_formatter) {
+    std::lock_guard<Mutex> lock(mutex_);
+    set_formatter_(std::move(sink_formatter));
+}
+
+template <typename Mutex>
+void SPDLOG_INLINE spdlog::sinks::base_sink<Mutex>::set_pattern_(const std::string &pattern) {
+    set_formatter_(details::make_unique<spdlog::pattern_formatter>(pattern));
+}
+
+template <typename Mutex>
+void SPDLOG_INLINE
+spdlog::sinks::base_sink<Mutex>::set_formatter_(std::unique_ptr<spdlog::formatter> sink_formatter) {
+    formatter_ = std::move(sink_formatter);
+}

spdlog/sinks/base_sink.h

@@ -0,0 +1,51 @@
+// Copyright(c) 2015-present, Gabi Melman & spdlog contributors.
+// Distributed under the MIT License (http://opensource.org/licenses/MIT)
+
+#pragma once
+//
+// base sink templated over a mutex (either dummy or real)
+// concrete implementation should override the sink_it_() and flush_()  methods.
+// locking is taken care of in this class - no locking needed by the
+// implementers..
+//
+
+#include <spdlog/common.h>
+#include <spdlog/details/log_msg.h>
+#include <spdlog/sinks/sink.h>
+
+namespace spdlog {
+namespace sinks {
+template <typename Mutex>
+class SPDLOG_API base_sink : public sink {
+public:
+    base_sink();
+    explicit base_sink(std::unique_ptr<spdlog::formatter> formatter);
+    ~base_sink() override = default;
+
+    base_sink(const base_sink &) = delete;
+    base_sink(base_sink &&) = delete;
+
+    base_sink &operator=(const base_sink &) = delete;
+    base_sink &operator=(base_sink &&) = delete;
+
+    void log(const details::log_msg &msg) final override;
+    void flush() final override;
+    void set_pattern(const std::string &pattern) final override;
+    void set_formatter(std::unique_ptr<spdlog::formatter> sink_formatter) final override;
+
+protected:
+    // sink formatter
+    std::unique_ptr<spdlog::formatter> formatter_;
+    Mutex mutex_;
+
+    virtual void sink_it_(const details::log_msg &msg) = 0;
+    virtual void flush_() = 0;
+    virtual void set_pattern_(const std::string &pattern);
+    virtual void set_formatter_(std::unique_ptr<spdlog::formatter> sink_formatter);
+};
+}  // namespace sinks
+}  // namespace spdlog
+
+#ifdef SPDLOG_HEADER_ONLY
+    #include "base_sink-inl.h"
+#endif

spdlog/sinks/basic_file_sink-inl.h

@@ -0,0 +1,48 @@
+// Copyright(c) 2015-present, Gabi Melman & spdlog contributors.
+// Distributed under the MIT License (http://opensource.org/licenses/MIT)
+
+#pragma once
+
+#ifndef SPDLOG_HEADER_ONLY
+    #include <spdlog/sinks/basic_file_sink.h>
+#endif
+
+#include <spdlog/common.h>
+#include <spdlog/details/os.h>
+
+namespace spdlog {
+namespace sinks {
+
+template <typename Mutex>
+SPDLOG_INLINE basic_file_sink<Mutex>::basic_file_sink(const filename_t &filename,
+                                                      bool truncate,
+                                                      const file_event_handlers &event_handlers)
+    : file_helper_{event_handlers} {
+    file_helper_.open(filename, truncate);
+}
+
+template <typename Mutex>
+SPDLOG_INLINE const filename_t &basic_file_sink<Mutex>::filename() const {
+    return file_helper_.filename();
+}
+
+template <typename Mutex>
+SPDLOG_INLINE void basic_file_sink<Mutex>::truncate() {
+    std::lock_guard<Mutex> lock(base_sink<Mutex>::mutex_);
+    file_helper_.reopen(true);
+}
+
+template <typename Mutex>
+SPDLOG_INLINE void basic_file_sink<Mutex>::sink_it_(const details::log_msg &msg) {
+    memory_buf_t formatted;
+    base_sink<Mutex>::formatter_->format(msg, formatted);
+    file_helper_.write(formatted);
+}
+
+template <typename Mutex>
+SPDLOG_INLINE void basic_file_sink<Mutex>::flush_() {
+    file_helper_.flush();
+}
+
+}  // namespace sinks
+}  // namespace spdlog

spdlog/sinks/basic_file_sink.h

@@ -0,0 +1,66 @@
+// Copyright(c) 2015-present, Gabi Melman & spdlog contributors.
+// Distributed under the MIT License (http://opensource.org/licenses/MIT)
+
+#pragma once
+
+#include <spdlog/details/file_helper.h>
+#include <spdlog/details/null_mutex.h>
+#include <spdlog/details/synchronous_factory.h>
+#include <spdlog/sinks/base_sink.h>
+
+#include <mutex>
+#include <string>
+
+namespace spdlog {
+namespace sinks {
+/*
+ * Trivial file sink with single file as target
+ */
+template <typename Mutex>
+class basic_file_sink final : public base_sink<Mutex> {
+public:
+    explicit basic_file_sink(const filename_t &filename,
+                             bool truncate = false,
+                             const file_event_handlers &event_handlers = {});
+    const filename_t &filename() const;
+    void truncate();
+
+protected:
+    void sink_it_(const details::log_msg &msg) override;
+    void flush_() override;
+
+private:
+    details::file_helper file_helper_;
+};
+
+using basic_file_sink_mt = basic_file_sink<std::mutex>;
+using basic_file_sink_st = basic_file_sink<details::null_mutex>;
+
+}  // namespace sinks
+
+//
+// factory functions
+//
+template <typename Factory = spdlog::synchronous_factory>
+inline std::shared_ptr<logger> basic_logger_mt(const std::string &logger_name,
+                                               const filename_t &filename,
+                                               bool truncate = false,
+                                               const file_event_handlers &event_handlers = {}) {
+    return Factory::template create<sinks::basic_file_sink_mt>(logger_name, filename, truncate,
+                                                               event_handlers);
+}
+
+template <typename Factory = spdlog::synchronous_factory>
+inline std::shared_ptr<logger> basic_logger_st(const std::string &logger_name,
+                                               const filename_t &filename,
+                                               bool truncate = false,
+                                               const file_event_handlers &event_handlers = {}) {
+    return Factory::template create<sinks::basic_file_sink_st>(logger_name, filename, truncate,
+                                                               event_handlers);
+}
+
+}  // namespace spdlog
+
+#ifdef SPDLOG_HEADER_ONLY
+    #include "basic_file_sink-inl.h"
+#endif