SKALE-1990 Add spdlog

spdlog/async.h

+// 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 <memory>
+#include <mutex>
+#include <functional>
+
+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, 1);
+            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)
+{
+    auto tp = std::make_shared<details::thread_pool>(q_size, thread_count, on_thread_start);
+    details::registry::instance().set_tp(std::move(tp));
+}
+
+// set global thread pool.
+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

+// 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/sinks/sink.h>
+#include <spdlog/details/thread_pool.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)
+{
+    if (auto pool_ptr = thread_pool_.lock())
+    {
+        pool_ptr->post_log(shared_from_this(), msg, overflow_policy_);
+    }
+    else
+    {
+        SPDLOG_THROW(spdlog_ex("async log: thread pool doesn't exist anymore"));
+    }
+}
+
+// send flush request to the thread pool
+SPDLOG_INLINE void spdlog::async_logger::flush_()
+{
+    if (auto pool_ptr = thread_pool_.lock())
+    {
+        pool_ptr->post_flush(shared_from_this(), overflow_policy_);
+    }
+    else
+    {
+        SPDLOG_THROW(spdlog_ex("async flush: thread pool doesn't exist anymore"));
+    }
+}
+
+//
+// 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()
+        }
+    }
+
+    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()
+    }
+}
+
+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

+// 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.
+};
+
+namespace details {
+class thread_pool;
+}
+
+class 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/common-inl.h

+// 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
+
+namespace spdlog {
+namespace level {
+static string_view_t level_string_views[] SPDLOG_LEVEL_NAMES;
+
+static const char *short_level_names[] SPDLOG_SHORT_LEVEL_NAMES;
+
+SPDLOG_INLINE 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
+{
+    int level = 0;
+    for (const auto &level_str : level_string_views)
+    {
+        if (level_str == name)
+        {
+            return static_cast<level::level_enum>(level);
+        }
+        level++;
+    }
+    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)
+{
+    memory_buf_t outbuf;
+    fmt::format_system_error(outbuf, last_errno, msg);
+    msg_ = fmt::to_string(outbuf);
+}
+
+SPDLOG_INLINE const char *spdlog_ex::what() const SPDLOG_NOEXCEPT
+{
+    return msg_.c_str();
+}
+
+} // namespace spdlog

spdlog/common.h

+// Copyright(c) 2015-present, Gabi Melman & spdlog contributors.
+// Distributed under the MIT License (http://opensource.org/licenses/MIT)
+
+#pragma once
+
+#include <spdlog/tweakme.h>
+#include <spdlog/details/null_mutex.h>
+
+#include <atomic>
+#include <chrono>
+#include <initializer_list>
+#include <memory>
+#include <exception>
+#include <string>
+#include <type_traits>
+#include <functional>
+
+#ifdef _WIN32
+#ifndef NOMINMAX
+#define NOMINMAX // prevent windows redefining min/max
+#endif
+
+#ifndef WIN32_LEAN_AND_MEAN
+#define WIN32_LEAN_AND_MEAN
+#endif
+
+#include <windows.h>
+#endif //_WIN32
+
+#ifdef SPDLOG_COMPILED_LIB
+#undef SPDLOG_HEADER_ONLY
+#define SPDLOG_INLINE
+#else
+#define SPDLOG_HEADER_ONLY
+#define SPDLOG_INLINE inline
+#endif
+
+#include <spdlog/fmt/fmt.h>
+
+// visual studio upto 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 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_ALL()
+#else
+#define SPDLOG_TRY try
+#define SPDLOG_THROW(ex) throw(ex)
+#define SPDLOG_CATCH_ALL() catch (...)
+#endif
+
+namespace spdlog {
+
+class formatter;
+
+namespace sinks {
+class sink;
+}
+
+#if defined(_WIN32) && defined(SPDLOG_WCHAR_FILENAMES)
+using filename_t = std::wstring;
+#define SPDLOG_FILENAME_T(s) L##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)>;
+using string_view_t = fmt::basic_string_view<char>;
+using wstring_view_t = fmt::basic_string_view<wchar_t>;
+using memory_buf_t = fmt::basic_memory_buffer<char, 250>;
+
+#ifdef SPDLOG_WCHAR_TO_UTF8_SUPPORT
+#ifndef _WIN32
+#error SPDLOG_WCHAR_TO_UTF8_SUPPORT only supported on windows
+#else
+template<typename T>
+struct is_convertible_to_wstring_view : std::is_convertible<T, wstring_view_t>
+{};
+#endif // _WIN32
+#else
+template<typename>
+struct is_convertible_to_wstring_view : std::false_type
+{};
+#endif // SPDLOG_WCHAR_TO_UTF8_SUPPORT
+
+#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
+{
+    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,
+};
+
+#if !defined(SPDLOG_LEVEL_NAMES)
+#define SPDLOG_LEVEL_NAMES                                                                                                                 \
+    {                                                                                                                                      \
+        "trace", "debug", "info", "warning", "error", "critical", "off"                                                                    \
+    }
+#endif
+
+#if !defined(SPDLOG_SHORT_LEVEL_NAMES)
+
+#define SPDLOG_SHORT_LEVEL_NAMES                                                                                                           \
+    {                                                                                                                                      \
+        "T", "D", "I", "W", "E", "C", "O"                                                                                                  \
+    }
+#endif
+
+string_view_t &to_string_view(spdlog::level::level_enum l) SPDLOG_NOEXCEPT;
+const char *to_short_c_str(spdlog::level::level_enum l) SPDLOG_NOEXCEPT;
+spdlog::level::level_enum from_str(const std::string &name) SPDLOG_NOEXCEPT;
+
+using level_hasher = std::hash<int>;
+} // 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_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_;
+};
+
+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};
+};
+
+namespace details {
+// make_unique support for pre c++14
+
+#if __cplusplus >= 201402L // C++14 and beyond
+using std::make_unique;
+#else
+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
+} // namespace details
+
+} // namespace spdlog
+
+#ifdef SPDLOG_HEADER_ONLY
+#include "common-inl.h"
+#endif

spdlog/details/backtracer-inl.h

+// 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});
+}
+
+// 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

+// 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/circular_q.h>
+
+#include <atomic>
+#include <mutex>
+#include <functional>
+
+// Store log messages in circular buffer.
+// Useful for storing debug data in case of error/warning happens.
+
+namespace spdlog {
+namespace details {
+class 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);
+
+    // 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
\ No newline at end of file

spdlog/details/circular_q.h

+// 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 <vector>
+#include <cassert>
+
+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_;
+    }
+
+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

+// 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 <mutex>
+
+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

+// 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/details/os.h>
+#include <spdlog/common.h>
+
+#include <cerrno>
+#include <chrono>
+#include <cstdio>
+#include <string>
+#include <thread>
+#include <tuple>
+
+namespace spdlog {
+namespace details {
+
+SPDLOG_INLINE file_helper::~file_helper()
+{
+    close();
+}
+
+SPDLOG_INLINE void file_helper::open(const filename_t &fname, bool truncate)
+{
+    close();
+    filename_ = fname;
+    auto *mode = truncate ? SPDLOG_FILENAME_T("wb") : SPDLOG_FILENAME_T("ab");
+
+    for (int tries = 0; tries < open_tries_; ++tries)
+    {
+        // create containing folder if not exists already.
+        os::create_dir(os::dir_name(fname));
+        if (!os::fopen_s(&fd_, fname, mode))
+        {
+            return;
+        }
+
+        details::os::sleep_for_millis(open_interval_);
+    }
+
+    SPDLOG_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())
+    {
+        SPDLOG_THROW(spdlog_ex("Failed re opening file - was not opened before"));
+    }
+    this->open(filename_, truncate);
+}
+
+SPDLOG_INLINE void file_helper::flush()
+{
+    std::fflush(fd_);
+}
+
+SPDLOG_INLINE void file_helper::close()
+{
+    if (fd_ != nullptr)
+    {
+        std::fclose(fd_);
+        fd_ = nullptr;
+    }
+}
+
+SPDLOG_INLINE void file_helper::write(const memory_buf_t &buf)
+{
+    size_t msg_size = buf.size();
+    auto data = buf.data();
+    if (std::fwrite(data, 1, msg_size, fd_) != msg_size)
+    {
+        SPDLOG_THROW(spdlog_ex("Failed writing to file " + os::filename_to_str(filename_), errno));
+    }
+}
+
+SPDLOG_INLINE size_t file_helper::size() const
+{
+    if (fd_ == nullptr)
+    {
+        SPDLOG_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.rfind(details::os::folder_sep);
+    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

+// 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 file_helper
+{
+public:
+    explicit file_helper() = default;
+
+    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 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 int open_interval_ = 10;
+    std::FILE *fd_{nullptr};
+    filename_t filename_;
+};
+} // namespace details
+} // namespace spdlog
+
+#ifdef SPDLOG_HEADER_ONLY
+#include "file_helper-inl.h"
+#endif

spdlog/details/fmt_helper.h

+// Copyright(c) 2015-present, Gabi Melman & spdlog contributors.
+// Distributed under the MIT License (http://opensource.org/licenses/MIT)
+#pragma once
+
+#include <chrono>
+#include <type_traits>
+#include <spdlog/fmt/fmt.h>
+#include <spdlog/common.h>
+
+// Some fmt helpers to efficiently format and pad ints and strings
+namespace spdlog {
+namespace details {
+namespace fmt_helper {
+
+inline spdlog::string_view_t to_string_view(const memory_buf_t &buf) SPDLOG_NOEXCEPT
+{
+    return spdlog::string_view_t{buf.data(), buf.size()};
+}
+
+inline void append_string_view(spdlog::string_view_t view, memory_buf_t &dest)
+{
+    auto *buf_ptr = view.data();
+    if (buf_ptr != nullptr)
+    {
+        dest.append(buf_ptr, buf_ptr + view.size());
+    }
+}
+
+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());
+}
+
+template<typename T>
+inline unsigned count_digits(T n)
+{
+    using count_type = typename std::conditional<(sizeof(T) > sizeof(uint32_t)), uint64_t, uint32_t>::type;
+    return static_cast<unsigned>(fmt::internal::count_digits(static_cast<count_type>(n)));
+}
+
+inline void pad2(int n, memory_buf_t &dest)
+{
+    if (n > 99)
+    {
+        append_int(n, dest);
+    }
+    else if (n > 9) // 10-99
+    {
+        dest.push_back(static_cast<char>('0' + n / 10));
+        dest.push_back(static_cast<char>('0' + n % 10));
+    }
+    else if (n >= 0) // 0-9
+    {
+        dest.push_back('0');
+        dest.push_back(static_cast<char>('0' + n));
+    }
+    else // negatives (unlikely, but just in case, let fmt deal with it)
+    {
+        fmt::format_to(dest, "{: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");
+    auto digits = count_digits(n);
+    if (width > digits)
+    {
+        const char *zeroes = "0000000000000000000";
+        dest.append(zeroes, zeroes + width - digits);
+    }
+    append_int(n, dest);
+}
+
+template<typename T>
+inline void pad3(T n, memory_buf_t &dest)
+{
+    pad_uint(n, 3, 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

+// 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::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(os::now())
+#ifndef SPDLOG_NO_THREAD_ID
+    , thread_id(os::thread_id())
+#endif
+    , source(loc)
+    , payload(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(source_loc{}, a_logger_name, lvl, msg)
+{}
+
+} // namespace details
+} // namespace spdlog

spdlog/details/log_msg.h

+// 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 log_msg
+{
+    log_msg() = default;
+    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;
+
+    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

+// 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

+// 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 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

+// 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 <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();
+    }
+
+    // try to dequeue item. if no item found. wait upto timeout and try again
+    // 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;
+    }
+
+#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();
+    }
+
+    // try to dequeue item. if no item found. wait upto timeout and try again
+    // 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;
+    }
+
+#endif
+
+    size_t overrun_counter()
+    {
+        std::unique_lock<std::mutex> lock(queue_mutex_);
+        return q_.overrun_counter();
+    }
+
+private:
+    std::mutex queue_mutex_;
+    std::condition_variable push_cv_;
+    std::condition_variable pop_cv_;
+    spdlog::details::circular_q<T> q_;
+};
+} // namespace details
+} // namespace spdlog

spdlog/details/null_mutex.h

+// 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 {}
+    bool try_lock() const
+    {
+        return true;
+    }
+};
+
+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.h

+// 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 <ctime> // std::time_t
+
+namespace spdlog {
+namespace details {
+namespace os {
+
+spdlog::log_clock::time_point now() SPDLOG_NOEXCEPT;
+
+std::tm localtime(const std::time_t &time_tt) SPDLOG_NOEXCEPT;
+
+std::tm localtime() SPDLOG_NOEXCEPT;
+
+std::tm gmtime(const std::time_t &time_tt) SPDLOG_NOEXCEPT;
+
+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
+#ifdef _WIN32
+static const char folder_sep = '\\';
+#else
+SPDLOG_CONSTEXPR static const char folder_sep = '/';
+#endif
+
+#ifdef SPDLOG_PREVENT_CHILD_FD
+void prevent_child_fd(FILE *f);
+#endif
+
+// fopen_s on non windows for writing
+bool fopen_s(FILE **fp, const filename_t &filename, const filename_t &mode);
+
+// Remove filename. return 0 on success
+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)
+int remove_if_exists(const filename_t &filename) SPDLOG_NOEXCEPT;
+
+int rename(const filename_t &filename1, const filename_t &filename2) SPDLOG_NOEXCEPT;
+
+// Return if file exists.
+bool path_exists(const filename_t &filename) SPDLOG_NOEXCEPT;
+
+// Return file size according to open FILE* object
+size_t filesize(FILE *f);
+
+// Return utc offset in minutes or throw spdlog_ex on failure
+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)
+size_t _thread_id() SPDLOG_NOEXCEPT;
+
+// Return current thread id as size_t (from thread local storage)
+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
+void sleep_for_millis(int milliseconds) SPDLOG_NOEXCEPT;
+
+std::string filename_to_str(const filename_t &filename);
+
+int pid() SPDLOG_NOEXCEPT;
+
+// Determine if the terminal supports colors
+// Source: https://github.com/agauniyal/rang/
+bool is_color_terminal() SPDLOG_NOEXCEPT;
+
+// Determine if the terminal attached
+// Source: https://github.com/agauniyal/rang/
+bool in_terminal(FILE *file) SPDLOG_NOEXCEPT;
+
+#if (defined(SPDLOG_WCHAR_TO_UTF8_SUPPORT) || defined(SPDLOG_WCHAR_FILENAMES)) && defined(_WIN32)
+void wstr_to_utf8buf(wstring_view_t wstr, memory_buf_t &target);
+#endif
+
+// Return directory name from given path or empty string
+// "abc/file" => "abc"
+// "abc/" => "abc"
+// "abc" => ""
+// "abc///" => "abc//"
+filename_t dir_name(filename_t path);
+
+// Create a dir from the given path.
+// Return true if succeeded or if this dir already exists.
+bool create_dir(filename_t path);
+
+} // namespace os
+} // namespace details
+} // namespace spdlog
+
+#ifdef SPDLOG_HEADER_ONLY
+#include "os-inl.h"
+#endif

spdlog/details/pattern_formatter.h

+// 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 <vector>
+
+namespace spdlog {
+namespace details {
+
+// padding information.
+struct padding_info
+{
+    enum 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_;
+    }
+    const size_t width_ = 0;
+    const pad_side side_ = left;
+    bool truncate_ = false;
+    bool enabled_ = false;
+};
+
+class 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 pattern_formatter final : public formatter
+{
+public:
+    explicit pattern_formatter(
+        std::string pattern, pattern_time_type time_type = pattern_time_type::local, std::string eol = spdlog::details::os::default_eol);
+
+    // 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;
+
+private:
+    std::string pattern_;
+    std::string eol_;
+    pattern_time_type pattern_time_type_;
+    std::tm cached_tm_;
+    std::chrono::seconds last_log_secs_;
+    std::vector<std::unique_ptr<details::flag_formatter>> formatters_;
+
+    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.
+    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/details/periodic_worker-inl.h

+// 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 {
+
+SPDLOG_INLINE periodic_worker::periodic_worker(const std::function<void()> &callback_fun, std::chrono::seconds interval)
+{
+    active_ = (interval > std::chrono::seconds::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();
+        }
+    });
+}
+
+// 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

+// 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 periodic_worker
+{
+public:
+    periodic_worker(const std::function<void()> &callback_fun, std::chrono::seconds interval);
+    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

+// 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/details/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 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_);
+    }
+
+    new_logger->set_level(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_);
+    // remove previous default logger from the map
+    if (default_logger_ != nullptr)
+    {
+        loggers_.erase(default_logger_->name());
+    }
+    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);
+    }
+    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::flush_every(std::chrono::seconds interval)
+{
+    std::lock_guard<std::mutex> lock(flusher_mutex_);
+    std::function<void()> clbk = std::bind(&registry::flush_all, this);
+    periodic_flusher_ = details::make_unique<periodic_worker>(clbk, interval);
+}
+
+SPDLOG_INLINE void registry::set_error_handler(void (*handler)(const std::string &msg))
+{
+    std::lock_guard<std::mutex> lock(logger_map_mutex_);
+    for (auto &l : loggers_)
+    {
+        l.second->set_error_handler(handler);
+    }
+    err_handler_ = 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_);
+    loggers_.erase(logger_name);
+    if (default_logger_ && default_logger_->name() == logger_name)
+    {
+        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 registry &registry::instance()
+{
+    static registry s_instance;
+    return s_instance;
+}
+
+SPDLOG_INLINE void registry::throw_if_exists_(const std::string &logger_name)
+{
+    if (loggers_.find(logger_name) != loggers_.end())
+    {
+        SPDLOG_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

+// 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 <chrono>
+#include <functional>
+#include <memory>
+#include <string>
+#include <unordered_map>
+#include <mutex>
+
+namespace spdlog {
+class logger;
+
+namespace details {
+class thread_pool;
+class periodic_worker;
+
+class registry
+{
+public:
+    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.
+    // default logger is stored in default_logger_ (for faster retrieval) and in the loggers_ map.
+    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);
+
+    void flush_every(std::chrono::seconds interval);
+
+    void set_error_handler(void (*handler)(const std::string &msg));
+
+    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);
+
+    static registry &instance();
+
+private:
+    registry();
+    ~registry() = default;
+
+    void throw_if_exists_(const std::string &logger_name);
+    void register_logger_(std::shared_ptr<logger> new_logger);
+    std::mutex logger_map_mutex_, flusher_mutex_;
+    std::recursive_mutex tp_mutex_;
+    std::unordered_map<std::string, std::shared_ptr<logger>> loggers_;
+    std::unique_ptr<formatter> formatter_;
+    level::level_enum level_ = level::info;
+    level::level_enum flush_level_ = level::off;
+    void (*err_handler_)(const std::string &msg);
+    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

+// 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
\ No newline at end of file

spdlog/details/thread_pool-inl.h

+// 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 <spdlog/common.h>
+#include <cassert>
+
+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)
+    : q_(q_max_items)
+{
+    if (threads_n == 0 || threads_n > 1000)
+    {
+        SPDLOG_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_start();
+            this->thread_pool::worker_loop_();
+        });
+    }
+}
+
+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_ALL() {}
+}
+
+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::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
+    {
+        q_.enqueue_nowait(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;
+    bool dequeued = q_.dequeue_for(incoming_async_msg, std::chrono::seconds(10));
+    if (!dequeued)
+    {
+        return true;
+    }
+
+    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 && "Unexpected async_msg_type");
+    }
+    }
+
+    return true;
+}
+
+} // namespace details
+} // namespace spdlog

spdlog/details/thread_pool.h

+// 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 <memory>
+#include <thread>
+#include <vector>
+#include <functional>
+
+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
+};
+
+#include <spdlog/details/log_msg_buffer.h>
+// 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 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);
+    thread_pool(size_t q_max_items, size_t threads_n);
+
+    // message all threads to terminate gracefully 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();
+
+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/fmt/bin_to_hex.h

+//
+// Copyright(c) 2015 Gabi Melman.
+// Distributed under the MIT License (http://opensource.org/licenses/MIT)
+//
+
+#pragma once
+
+//
+// Support for logging binary data as hex
+// format flags:
+// {: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.
+
+//
+// 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)));
+
+namespace spdlog {
+namespace details {
+
+template<typename It>
+class bytes_range
+{
+public:
+    bytes_range(It range_begin, It range_end)
+        : begin_(range_begin)
+        , end_(range_end)
+    {}
+
+    It begin() const
+    {
+        return begin_;
+    }
+    It end() const
+    {
+        return end_;
+    }
+
+private:
+    It begin_, end_;
+};
+} // namespace details
+
+// create a bytes_range that wraps the given container
+template<typename Container>
+inline details::bytes_range<typename Container::const_iterator> to_hex(const Container &container)
+{
+    static_assert(sizeof(typename Container::value_type) == 1, "sizeof(Container::value_type) != 1");
+    using Iter = typename Container::const_iterator;
+    return details::bytes_range<Iter>(std::begin(container), std::end(container));
+}
+
+// create bytes_range from ranges
+template<typename It>
+inline details::bytes_range<It> to_hex(const It range_begin, const It range_end)
+{
+    return details::bytes_range<It>(range_begin, range_end);
+}
+
+} // namespace spdlog
+
+namespace fmt {
+
+template<typename T>
+struct formatter<spdlog::details::bytes_range<T>>
+{
+    const std::size_t line_size = 100;
+    const char delimiter = ' ';
+
+    bool put_newlines = true;
+    bool put_delimiters = true;
+    bool use_uppercase = false;
+    bool put_positions = true; // position on start of each line
+
+    // parse the format string flags
+    template<typename ParseContext>
+    auto parse(ParseContext &ctx) -> decltype(ctx.begin())
+    {
+        auto it = ctx.begin();
+        while (*it && *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;
+                break;
+            }
+
+            ++it;
+        }
+        return it;
+    }
+
+    // format the given bytes range as hex
+    template<typename FormatContext, typename Container>
+    auto format(const spdlog::details::bytes_range<Container> &the_range, FormatContext &ctx) -> 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;
+
+        std::size_t pos = 0;
+        std::size_t column = line_size;
+#if FMT_VERSION < 60000
+        auto inserter = ctx.begin();
+#else
+        auto inserter = ctx.out();
+#endif
+
+        for (auto &item : the_range)
+        {
+            auto ch = static_cast<unsigned char>(item);
+            pos++;
+
+            if (put_newlines && column >= line_size)
+            {
+                column = put_newline(inserter, pos);
+
+                // put first byte without delimiter in front of it
+                *inserter++ = hex_chars[(ch >> 4) & 0x0f];
+                *inserter++ = hex_chars[ch & 0x0f];
+                column += 2;
+                continue;
+            }
+
+            if (put_delimiters)
+            {
+                *inserter++ = delimiter;
+                ++column;
+            }
+
+            *inserter++ = hex_chars[(ch >> 4) & 0x0f];
+            *inserter++ = hex_chars[ch & 0x0f];
+            column += 2;
+        }
+        return inserter;
+    }
+
+    // put newline(and position header)
+    // return the next column
+    template<typename It>
+    std::size_t put_newline(It inserter, std::size_t pos)
+    {
+#ifdef _WIN32
+        *inserter++ = '\r';
+#endif
+        *inserter++ = '\n';
+
+        if (put_positions)
+        {
+            fmt::format_to(inserter, "{:<04X}: ", pos - 1);
+            return 7;
+        }
+        else
+        {
+            return 1;
+        }
+    }
+};
+} // namespace fmt

spdlog/fmt/bundled/LICENSE.rst

+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/locale.h

+// Formatting library for C++ - std::locale support
+//
+// Copyright (c) 2012 - present, Victor Zverovich
+// All rights reserved.
+//
+// For the license information refer to format.h.
+
+#ifndef FMT_LOCALE_H_
+#define FMT_LOCALE_H_
+
+#include <locale>
+#include "format.h"
+
+FMT_BEGIN_NAMESPACE
+
+namespace internal {
+template <typename Char>
+typename buffer_context<Char>::iterator vformat_to(
+    const std::locale& loc, buffer<Char>& buf,
+    basic_string_view<Char> format_str,
+    basic_format_args<buffer_context<Char>> args) {
+  using range = buffer_range<Char>;
+  return vformat_to<arg_formatter<range>>(buf, to_string_view(format_str), args,
+                                          internal::locale_ref(loc));
+}
+
+template <typename Char>
+std::basic_string<Char> vformat(const std::locale& loc,
+                                basic_string_view<Char> format_str,
+                                basic_format_args<buffer_context<Char>> args) {
+  basic_memory_buffer<Char> buffer;
+  internal::vformat_to(loc, buffer, format_str, args);
+  return fmt::to_string(buffer);
+}
+}  // namespace internal
+
+template <typename S, typename Char = char_t<S>>
+inline std::basic_string<Char> vformat(
+    const std::locale& loc, const S& format_str,
+    basic_format_args<buffer_context<Char>> args) {
+  return internal::vformat(loc, to_string_view(format_str), args);
+}
+
+template <typename S, typename... Args, typename Char = char_t<S>>
+inline std::basic_string<Char> format(const std::locale& loc,
+                                      const S& format_str, Args&&... args) {
+  return internal::vformat(
+      loc, to_string_view(format_str),
+      {internal::make_args_checked<Args...>(format_str, args...)});
+}
+
+template <typename S, typename OutputIt, typename... Args,
+          typename Char = enable_if_t<
+              internal::is_output_iterator<OutputIt>::value, char_t<S>>>
+inline OutputIt vformat_to(OutputIt out, const std::locale& loc,
+                           const S& format_str,
+                           format_args_t<OutputIt, Char> args) {
+  using range = internal::output_range<OutputIt, Char>;
+  return vformat_to<arg_formatter<range>>(
+      range(out), to_string_view(format_str), args, internal::locale_ref(loc));
+}
+
+template <typename OutputIt, typename S, typename... Args,
+          FMT_ENABLE_IF(internal::is_output_iterator<OutputIt>::value&&
+                            internal::is_string<S>::value)>
+inline OutputIt format_to(OutputIt out, const std::locale& loc,
+                          const S& format_str, Args&&... args) {
+  internal::check_format_string<Args...>(format_str);
+  using context = format_context_t<OutputIt, char_t<S>>;
+  format_arg_store<context, Args...> as{args...};
+  return vformat_to(out, loc, to_string_view(format_str),
+                    basic_format_args<context>(as));
+}
+
+FMT_END_NAMESPACE
+
+#endif  // FMT_LOCALE_H_

spdlog/fmt/bundled/ostream.h

+// 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_
+
+#include <ostream>
+#include "format.h"
+
+FMT_BEGIN_NAMESPACE
+namespace internal {
+
+template <class Char> class formatbuf : public std::basic_streambuf<Char> {
+ private:
+  using int_type = typename std::basic_streambuf<Char>::int_type;
+  using traits_type = typename std::basic_streambuf<Char>::traits_type;
+
+  buffer<Char>& buffer_;
+
+ public:
+  formatbuf(buffer<Char>& buf) : buffer_(buf) {}
+
+ protected:
+  // The put-area is actually always empty. This makes the implementation
+  // simpler and has the advantage that the streambuf and the buffer are always
+  // in sync and sputc never writes into uninitialized memory. The obvious
+  // disadvantage is that each call to sputc always results in a (virtual) call
+  // to overflow. There is no disadvantage here for sputn since this always
+  // results in a call to xsputn.
+
+  int_type overflow(int_type ch = traits_type::eof()) FMT_OVERRIDE {
+    if (!traits_type::eq_int_type(ch, traits_type::eof()))
+      buffer_.push_back(static_cast<Char>(ch));
+    return ch;
+  }
+
+  std::streamsize xsputn(const Char* s, std::streamsize count) FMT_OVERRIDE {
+    buffer_.append(s, s + count);
+    return count;
+  }
+};
+
+template <typename Char> struct test_stream : std::basic_ostream<Char> {
+ private:
+  // Hide all operator<< from std::basic_ostream<Char>.
+  void_t<> operator<<(null<>);
+  void_t<> operator<<(const Char*);
+
+  template <typename T, FMT_ENABLE_IF(std::is_convertible<T, int>::value &&
+                                      !std::is_enum<T>::value)>
+  void_t<> operator<<(T);
+};
+
+// Checks if T has a user-defined operator<< (e.g. not a member of
+// std::ostream).
+template <typename T, typename Char> class is_streamable {
+ private:
+  template <typename U>
+  static bool_constant<!std::is_same<decltype(std::declval<test_stream<Char>&>()
+                                              << std::declval<U>()),
+                                     void_t<>>::value>
+  test(int);
+
+  template <typename> static std::false_type test(...);
+
+  using result = decltype(test<T>(0));
+
+ public:
+  static const bool value = result::value;
+};
+
+// Write the content of buf to os.
+template <typename Char>
+void write(std::basic_ostream<Char>& os, buffer<Char>& buf) {
+  const Char* buf_data = buf.data();
+  using unsigned_streamsize = std::make_unsigned<std::streamsize>::type;
+  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 Char, typename T>
+void format_value(buffer<Char>& buf, const T& value,
+                  locale_ref loc = locale_ref()) {
+  formatbuf<Char> format_buf(buf);
+  std::basic_ostream<Char> output(&format_buf);
+  if (loc) output.imbue(loc.get<std::locale>());
+  output.exceptions(std::ios_base::failbit | std::ios_base::badbit);
+  output << value;
+  buf.resize(buf.size());
+}
+
+// Formats an object of type T that has an overloaded ostream operator<<.
+template <typename T, typename Char>
+struct fallback_formatter<T, Char, enable_if_t<is_streamable<T, Char>::value>>
+    : formatter<basic_string_view<Char>, Char> {
+  template <typename Context>
+  auto format(const T& value, Context& ctx) -> decltype(ctx.out()) {
+    basic_memory_buffer<Char> buffer;
+    format_value(buffer, value, ctx.locale());
+    basic_string_view<Char> str(buffer.data(), buffer.size());
+    return formatter<basic_string_view<Char>, Char>::format(str, ctx);
+  }
+};
+}  // namespace internal
+
+template <typename Char>
+void vprint(std::basic_ostream<Char>& os, basic_string_view<Char> format_str,
+            basic_format_args<buffer_context<Char>> args) {
+  basic_memory_buffer<Char> buffer;
+  internal::vformat_to(buffer, format_str, args);
+  internal::write(os, buffer);
+}
+
+/**
+  \rst
+  Prints formatted data to the stream *os*.
+
+  **Example**::
+
+    fmt::print(cerr, "Don't {}!", "panic");
+  \endrst
+ */
+template <typename S, typename... Args,
+          typename Char = enable_if_t<internal::is_string<S>::value, char_t<S>>>
+void print(std::basic_ostream<Char>& os, const S& format_str, Args&&... args) {
+  vprint(os, to_string_view(format_str),
+         {internal::make_args_checked<Args...>(format_str, args...)});
+}
+FMT_END_NAMESPACE
+
+#endif  // FMT_OSTREAM_H_

spdlog/fmt/fmt.h

+//
+// 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.
+//
+
+#if !defined(SPDLOG_FMT_EXTERNAL)
+#ifdef SPDLOG_HEADER_ONLY
+#ifndef FMT_HEADER_ONLY
+#define FMT_HEADER_ONLY
+#endif
+#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
\ No newline at end of file

spdlog/fmt/ostr.h

+//
+// 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
+//
+
+#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

spdlog/formatter.h

+// Copyright(c) 2015-present, Gabi Melman & spdlog contributors.
+// Distributed under the MIT License (http://opensource.org/licenses/MIT)
+
+#pragma once
+
+#include <spdlog/fmt/fmt.h>
+#include <spdlog/details/log_msg.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/sinks/android_sink.h

+// 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/sinks/base_sink.h>
+#include <spdlog/details/synchronous_factory.h>
+
+#include <android/log.h>
+#include <chrono>
+#include <mutex>
+#include <string>
+#include <thread>
+
+#if !defined(SPDLOG_ANDROID_RETRIES)
+#define SPDLOG_ANDROID_RETRIES 2
+#endif
+
+namespace spdlog {
+namespace sinks {
+
+/*
+ * Android sink (logging using __android_log_write)
+ */
+template<typename Mutex>
+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_write(priority, tag_.c_str(), msg_output);
+        int retry_count = 0;
+        while ((ret == -11 /*EAGAIN*/) && (retry_count < SPDLOG_ANDROID_RETRIES))
+        {
+            details::os::sleep_for_millis(5);
+            ret = __android_log_write(priority, tag_.c_str(), msg_output);
+            retry_count++;
+        }
+
+        if (ret < 0)
+        {
+            SPDLOG_THROW(spdlog_ex("__android_log_write() failed", ret));
+        }
+    }
+
+    void flush_() override {}
+
+private:
+    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>;
+} // 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__
\ No newline at end of file

spdlog/sinks/base_sink-inl.h

+// 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/details/pattern_formatter.h>
+
+#include <memory>
+
+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/sink-inl.h

+// 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/sink.h>
+#endif
+
+#include <spdlog/common.h>
+
+SPDLOG_INLINE bool spdlog::sinks::sink::should_log(spdlog::level::level_enum msg_level) const
+{
+    return msg_level >= level_.load(std::memory_order_relaxed);
+}
+
+SPDLOG_INLINE void spdlog::sinks::sink::set_level(level::level_enum log_level)
+{
+    level_.store(log_level, std::memory_order_relaxed);
+}
+
+SPDLOG_INLINE spdlog::level::level_enum spdlog::sinks::sink::level() const
+{
+    return static_cast<spdlog::level::level_enum>(level_.load(std::memory_order_relaxed));
+}

spdlog/version.h

+// Copyright(c) 2015-present, Gabi Melman & spdlog contributors.
+// Distributed under the MIT License (http://opensource.org/licenses/MIT)
+
+#pragma once
+
+#define SPDLOG_VER_MAJOR 1
+#define SPDLOG_VER_MINOR 5
+#define SPDLOG_VER_PATCH 0
+
+#define SPDLOG_VERSION (SPDLOG_VER_MAJOR * 10000 + SPDLOG_VER_MINOR * 100 + SPDLOG_VER_PATCH)