fixed flush interval in async helper

example/bench.cpp

@@ -7,7 +7,8 @@
 // bench.cpp : spdlog benchmarks
 //
 #include "spdlog/async_logger.h"
-#include "spdlog/sinks/test_sink.h"
+#include "spdlog/sinks/file_sinks.h"
+#include "spdlog/sinks/null_sink.h"
 #include "spdlog/spdlog.h"
 #include "utils.h"
 #include <atomic>
@@ -29,10 +30,12 @@ void bench_mt(int howmany, std::shared_ptr<spdlog::logger> log, int thread_count
 int main(int argc, char *argv[])
 {
 
-    int queue_size = 1024*1024;
+    int queue_size = 1048576;
     int howmany = 1000000;
     int threads = 10;
- 
+    int file_size = 30 * 1024 * 1024;
+    int rotating_files = 5;
+
     try
     {
 
@@ -42,7 +45,7 @@ int main(int argc, char *argv[])
             threads = atoi(argv[2]);
         if (argc > 3)
             queue_size = atoi(argv[3]);
-		/*
+
         cout << "*******************************************************************************\n";
         cout << "Single thread, " << format(howmany) << " iterations" << endl;
         cout << "*******************************************************************************\n";
@@ -64,32 +67,17 @@ int main(int argc, char *argv[])
         bench_mt(howmany, daily_mt, threads);
         bench(howmany, spdlog::create<null_sink_st>("null_mt"));
 
-		*/
-
         cout << "\n*******************************************************************************\n";
         cout << "async logging.. " << threads << " threads sharing same logger, " << format(howmany) << " iterations " << endl;
         cout << "*******************************************************************************\n";
 
         spdlog::set_async_mode(queue_size);
 
-		
-        for (int i = 0; i < 300; ++i)
+        for (int i = 0; i < 3; ++i)
         {
-            //auto as = spdlog::daily_logger_mt("as", "logs/daily_async.log");
-			auto test_sink = std::make_shared<spdlog::sinks::test_sink_mt>();
-			//auto as = spdlog::basic_logger_mt("as", "logs/async.log", true);
-			auto as = std::make_shared<spdlog::async_logger>("as", test_sink, queue_size, async_overflow_policy::block_retry, nullptr, std::chrono::milliseconds(2000));
-            bench_mt(howmany, as, threads);			
-			as.reset();
+            auto as = spdlog::daily_logger_st("as", "logs/daily_async.log");
+            bench_mt(howmany, as, threads);
             spdlog::drop("as");
-
-			auto msg_counter = test_sink->msg_counter();
-			cout << "Count:" << msg_counter << endl;
-			if (msg_counter != howmany)
-			{
-				cout << "ERROR! Expected " << howmany;
-				exit(0);
-			}
         }
     }
     catch (std::exception &ex)
@@ -131,7 +119,6 @@ void bench_mt(int howmany, std::shared_ptr<spdlog::logger> log, int thread_count
                 if (counter > howmany)
                     break;
                 log->info("Hello logger: msg number {}", counter);
-				//std::this_thread::sleep_for(std::chrono::milliseconds(1000));
             }
         }));
     }

include/spdlog/contrib/sinks/step_file_sink.h

@@ -17,8 +17,10 @@
 //
 // Create a file logger which creates new files with a specified time step and fixed file size:
 //
-// std::shared_ptr<logger> step_logger_mt(const std::string &logger_name, const filename_t &filename, unsigned seconds = 60, const filename_t &tmp_ext = ".tmp", unsigned max_file_size = std::numeric_limits<unsigned>::max());
-// std::shared_ptr<logger> step_logger_st(const std::string &logger_name, const filename_t &filename, unsigned seconds = 60, const filename_t &tmp_ext = ".tmp", unsigned max_file_size = std::numeric_limits<unsigned>::max());
+// std::shared_ptr<logger> step_logger_mt(const std::string &logger_name, const filename_t &filename, unsigned seconds = 60, const
+// filename_t &tmp_ext = ".tmp", unsigned max_file_size = std::numeric_limits<unsigned>::max()); std::shared_ptr<logger>
+// step_logger_st(const std::string &logger_name, const filename_t &filename, unsigned seconds = 60, const filename_t &tmp_ext = ".tmp",
+// unsigned max_file_size = std::numeric_limits<unsigned>::max());
 
 // Example for spdlog_impl.h
 // Create a file logger that creates new files with a specified increment
@@ -76,7 +78,7 @@ public:
         {
             throw spdlog_ex("step_file_sink: Invalid max log size in ctor");
         }
-        
+
         _tp = _next_tp();
         std::tie(_current_filename, _ext) = FileNameCalc::calc_filename(_base_filename, _tmp_ext);
 
@@ -88,7 +90,7 @@ public:
         _file_helper.open(_current_filename);
         _current_size = _file_helper.size(); // expensive. called only once
     }
-    
+
     ~step_file_sink()
     {
         try
@@ -96,7 +98,8 @@ public:
             close_current_file();
         }
         catch (...)
-        {}
+        {
+        }
     }
 
 protected:
@@ -130,7 +133,7 @@ private:
     {
         using details::os::filename_to_str;
 
-        filename_t src =_current_filename, target;
+        filename_t src = _current_filename, target;
         std::tie(target, std::ignore) = details::file_helper::split_by_extenstion(src);
         target += _ext;
 
@@ -149,7 +152,7 @@ private:
     filename_t _current_filename;
     filename_t _ext;
     unsigned _current_size;
-    
+
     details::file_helper _file_helper;
 };
 

include/spdlog/details/async_log_helper.h

@@ -19,342 +19,337 @@
 #include "../formatter.h"
 #include "../sinks/sink.h"
 
-#include<iostream>
 #include <chrono>
+#include <condition_variable>
 #include <exception>
 #include <functional>
+#include <iostream>
 #include <memory>
 #include <string>
 #include <thread>
 #include <utility>
 #include <vector>
-#include <condition_variable>
 
 namespace spdlog {
-	namespace details {
-
-		class async_log_helper
-		{
-			// Async msg to move to/from the queue
-			// Movable only. should never be copied
-			enum class async_msg_type
-			{
-				log,
-				flush,
-				terminate
-			};
-
-			struct async_msg
-			{
-				std::string logger_name;
-				level::level_enum level;
-				log_clock::time_point time;
-				size_t thread_id;
-				std::string txt;
-				async_msg_type msg_type;
-				size_t msg_id;
-
-				async_msg() = default;
-				~async_msg() = default;
-
-				explicit async_msg(async_msg_type m_type)
-					: level(level::info)
-					, thread_id(0)
-					, msg_type(m_type)
-					, msg_id(0)
-				{
-				}
-
-				async_msg(async_msg &&other) SPDLOG_NOEXCEPT : logger_name(std::move(other.logger_name)),
-					level(std::move(other.level)),
-					time(std::move(other.time)),
-					thread_id(other.thread_id),
-					txt(std::move(other.txt)),
-					msg_type(std::move(other.msg_type)),
-					msg_id(other.msg_id)
-				{
-				}
-
-				async_msg &operator=(async_msg &&other) SPDLOG_NOEXCEPT
-				{
-					logger_name = std::move(other.logger_name);
-					level = other.level;
-					time = std::move(other.time);
-					thread_id = other.thread_id;
-					txt = std::move(other.txt);
-					msg_type = other.msg_type;
-					msg_id = other.msg_id;
-					return *this;
-				}
-
-				// never copy or assign. should only be moved..
-				async_msg(const async_msg &) = delete;
-				async_msg &operator=(const async_msg &other) = delete;
-
-				// construct from log_msg
-				explicit async_msg(const details::log_msg &m)
-					: level(m.level)
-					, time(m.time)
-					, thread_id(m.thread_id)
-					, txt(m.raw.data(), m.raw.size())
-					, msg_type(async_msg_type::log)
-					, msg_id(m.msg_id)
-				{
+namespace details {
+
+class async_log_helper
+{
+    // Async msg to move to/from the queue
+    // Movable only. should never be copied
+    enum class async_msg_type
+    {
+        log,
+        flush,
+        terminate
+    };
+
+    struct async_msg
+    {
+        std::string logger_name;
+        level::level_enum level;
+        log_clock::time_point time;
+        size_t thread_id;
+        std::string txt;
+        async_msg_type msg_type;
+        size_t msg_id;
+
+        async_msg() = default;
+        ~async_msg() = default;
+
+        explicit async_msg(async_msg_type m_type)
+            : level(level::info)
+            , thread_id(0)
+            , msg_type(m_type)
+            , msg_id(0)
+        {
+        }
+
+        async_msg(async_msg &&other) SPDLOG_NOEXCEPT : logger_name(std::move(other.logger_name)),
+                                                       level(std::move(other.level)),
+                                                       time(std::move(other.time)),
+                                                       thread_id(other.thread_id),
+                                                       txt(std::move(other.txt)),
+                                                       msg_type(std::move(other.msg_type)),
+                                                       msg_id(other.msg_id)
+        {
+        }
+
+        async_msg &operator=(async_msg &&other) SPDLOG_NOEXCEPT
+        {
+            logger_name = std::move(other.logger_name);
+            level = other.level;
+            time = std::move(other.time);
+            thread_id = other.thread_id;
+            txt = std::move(other.txt);
+            msg_type = other.msg_type;
+            msg_id = other.msg_id;
+            return *this;
+        }
+
+        // never copy or assign. should only be moved..
+        async_msg(const async_msg &) = delete;
+        async_msg &operator=(const async_msg &other) = delete;
+
+        // construct from log_msg
+        explicit async_msg(const details::log_msg &m)
+            : level(m.level)
+            , time(m.time)
+            , thread_id(m.thread_id)
+            , txt(m.raw.data(), m.raw.size())
+            , msg_type(async_msg_type::log)
+            , msg_id(m.msg_id)
+        {
 #ifndef SPDLOG_NO_NAME
-					logger_name = *m.logger_name;
+            logger_name = *m.logger_name;
 #endif
-				}
+        }
 
-				// copy into log_msg
-				void fill_log_msg(log_msg &msg)
-				{
-					msg.logger_name = &logger_name;
-					msg.level = level;
-					msg.time = time;
-					msg.thread_id = thread_id;
-					msg.raw << txt;
-					msg.msg_id = msg_id;
-				}
-			};
+        // copy into log_msg
+        void fill_log_msg(log_msg &msg)
+        {
+            msg.logger_name = &logger_name;
+            msg.level = level;
+            msg.time = time;
+            msg.thread_id = thread_id;
+            msg.raw << txt;
+            msg.msg_id = msg_id;
+        }
+    };
 
-		public:
-			using item_type = async_msg;
-			using q_type = details::mpmc_bounded_queue <item_type>;
+public:
+    using item_type = async_msg;
+    using q_type = details::mpmc_bounded_queue<item_type>;
 
-			using clock = std::chrono::steady_clock;
+    using clock = std::chrono::steady_clock;
 
-			async_log_helper(formatter_ptr formatter, std::vector<sink_ptr> sinks, size_t queue_size, const log_err_handler err_handler,
-				const async_overflow_policy overflow_policy = async_overflow_policy::block_retry, std::function<void()> worker_warmup_cb = nullptr,
-				const std::chrono::milliseconds &flush_interval_ms = std::chrono::milliseconds::zero(),
-				std::function<void()> worker_teardown_cb = nullptr);
+    async_log_helper(formatter_ptr formatter, std::vector<sink_ptr> sinks, size_t queue_size, const log_err_handler err_handler,
+        const async_overflow_policy overflow_policy = async_overflow_policy::block_retry, std::function<void()> worker_warmup_cb = nullptr,
+        const std::chrono::milliseconds &flush_interval_ms = std::chrono::milliseconds::zero(),
+        std::function<void()> worker_teardown_cb = nullptr);
 
-			void log(const details::log_msg &msg);
+    void log(const details::log_msg &msg);
 
-			// stop logging and join the back thread
-			~async_log_helper();
+    // stop logging and join the back thread
+    ~async_log_helper();
 
-			async_log_helper(const async_log_helper &) = delete;
-			async_log_helper &operator=(const async_log_helper &) = delete;
+    async_log_helper(const async_log_helper &) = delete;
+    async_log_helper &operator=(const async_log_helper &) = delete;
 
-			void set_formatter(formatter_ptr msg_formatter);
+    void set_formatter(formatter_ptr msg_formatter);
 
-			void flush();
+    void flush();
 
-			void set_error_handler(spdlog::log_err_handler err_handler);
+    void set_error_handler(spdlog::log_err_handler err_handler);
 
-		private:
-			formatter_ptr _formatter;
-			std::vector<std::shared_ptr<sinks::sink>> _sinks;
+private:
+    formatter_ptr _formatter;
+    std::vector<std::shared_ptr<sinks::sink>> _sinks;
 
-			// queue of messages to log
-			q_type _q;
+    // queue of messages to log
+    q_type _q;
 
-			log_err_handler _err_handler;
+    log_err_handler _err_handler;
 
-			std::chrono::time_point<log_clock> _last_flush;
+    std::chrono::time_point<log_clock> _last_flush;
 
-			// overflow policy
-			const async_overflow_policy _overflow_policy;
+    // overflow policy
+    const async_overflow_policy _overflow_policy;
 
-			// worker thread warmup callback - one can set thread priority, affinity, etc
-			const std::function<void()> _worker_warmup_cb;
+    // worker thread warmup callback - one can set thread priority, affinity, etc
+    const std::function<void()> _worker_warmup_cb;
 
-			// auto periodic sink flush parameter
-			const std::chrono::milliseconds _flush_interval_ms;
+    // auto periodic sink flush parameter
+    const std::chrono::milliseconds _flush_interval_ms;
 
-			// worker thread teardown callback
-			const std::function<void()> _worker_teardown_cb;
+    // worker thread teardown callback
+    const std::function<void()> _worker_teardown_cb;
 
-			std::mutex null_mutex_;
-			//null_mutex null_mutex_;
-			std::condition_variable_any not_empty_cv_;
-			std::condition_variable_any not_full_cv_;
+    std::mutex null_mutex_;
+    // null_mutex null_mutex_;
+    std::condition_variable_any not_empty_cv_;
+    std::condition_variable_any not_full_cv_;
 
-			// worker thread
-			std::thread _worker_thread;
+    // worker thread
+    std::thread _worker_thread;
 
-			void enqueue_msg(async_msg &&new_msg, async_overflow_policy policy);
+    void enqueue_msg(async_msg &&new_msg, async_overflow_policy policy);
 
-			// worker thread main loop
-			void worker_loop();
+    // worker thread main loop
+    void worker_loop();
 
-			// dequeue next message from the queue and process it. 
-			// return false if termination of the queue is required
-			bool process_next_msg();
+    // dequeue next message from the queue and process it.
+    // return false if termination of the queue is required
+    bool process_next_msg();
 
-			void handle_flush_interval();
+    void handle_flush_interval();
 
-			void flush_sinks();
-			
-		};
-	} // namespace details
+    void flush_sinks();
+};
+} // namespace details
 } // namespace spdlog
 
 ///////////////////////////////////////////////////////////////////////////////
 // async_sink class implementation
 ///////////////////////////////////////////////////////////////////////////////
 inline spdlog::details::async_log_helper::async_log_helper(formatter_ptr formatter, std::vector<sink_ptr> sinks, size_t queue_size,
-	log_err_handler err_handler, const async_overflow_policy overflow_policy, std::function<void()> worker_warmup_cb,
-	const std::chrono::milliseconds &flush_interval_ms, std::function<void()> worker_teardown_cb)
-	: _formatter(std::move(formatter))
-	, _sinks(std::move(sinks))
-	, _q(queue_size)
-	, _err_handler(std::move(err_handler))
-	, _last_flush(os::now())
-	, _overflow_policy(overflow_policy)
-	, _worker_warmup_cb(std::move(worker_warmup_cb))
-	, _flush_interval_ms(flush_interval_ms)
-	, _worker_teardown_cb(std::move(worker_teardown_cb))
+    log_err_handler err_handler, const async_overflow_policy overflow_policy, std::function<void()> worker_warmup_cb,
+    const std::chrono::milliseconds &flush_interval_ms, std::function<void()> worker_teardown_cb)
+    : _formatter(std::move(formatter))
+    , _sinks(std::move(sinks))
+    , _q(queue_size)
+    , _err_handler(std::move(err_handler))
+    , _last_flush(os::now())
+    , _overflow_policy(overflow_policy)
+    , _worker_warmup_cb(std::move(worker_warmup_cb))
+    , _flush_interval_ms(flush_interval_ms)
+    , _worker_teardown_cb(std::move(worker_teardown_cb))
 {
-	_worker_thread = std::thread(&async_log_helper::worker_loop, this);
+    _worker_thread = std::thread(&async_log_helper::worker_loop, this);
 }
 
 // Send to the worker thread termination message(level=off)
 // and wait for it to finish gracefully
 inline spdlog::details::async_log_helper::~async_log_helper()
 {
-	try
-	{
-		enqueue_msg(async_msg(async_msg_type::terminate), async_overflow_policy::block_retry);
-		_worker_thread.join();
-	}
-	catch (...) // don't crash in destructor
-	{
-	}
+    try
+    {
+        enqueue_msg(async_msg(async_msg_type::terminate), async_overflow_policy::block_retry);
+        _worker_thread.join();
+    }
+    catch (...) // don't crash in destructor
+    {
+    }
 }
 
 // Try to push and block until succeeded (if the policy is not to discard when the queue is full)
 inline void spdlog::details::async_log_helper::log(const details::log_msg &msg)
-{	
-	enqueue_msg(async_msg(msg), _overflow_policy);	
+{
+    enqueue_msg(async_msg(msg), _overflow_policy);
 }
 
 inline void spdlog::details::async_log_helper::enqueue_msg(details::async_log_helper::async_msg &&new_msg, async_overflow_policy policy)
 {
 
-	// block until succeeded pushing to the queue
-	if (policy == async_overflow_policy::block_retry)
-	{
-		_q.enqueue(std::move(new_msg));
-	}
-	else
-	{
-		_q.enqueue_nowait(std::move(new_msg));
-	}
-	
+    // block until succeeded pushing to the queue
+    if (policy == async_overflow_policy::block_retry)
+    {
+        _q.enqueue(std::move(new_msg));
+    }
+    else
+    {
+        _q.enqueue_nowait(std::move(new_msg));
+    }
 }
 
 // optionally wait for the queue be empty and request flush from the sinks
 inline void spdlog::details::async_log_helper::flush()
 {
-	enqueue_msg(async_msg(async_msg_type::flush), _overflow_policy);
+    enqueue_msg(async_msg(async_msg_type::flush), _overflow_policy);
 }
 
 inline void spdlog::details::async_log_helper::worker_loop()
 {
-	if (_worker_warmup_cb)
-	{
-		_worker_warmup_cb();
-	}
-	auto active = true;
-	while (active)
-	{
-		try
-		{
-			active = process_next_msg();		
-		}
-		catch (const std::exception &ex)
-		{
-			_err_handler(ex.what());
-		}
-		catch (...)
-		{
-			_err_handler("Unknown exeption in async logger worker loop.");
-		}
-	}
-	if (_worker_teardown_cb)
-	{
-		_worker_teardown_cb();
-	}
+    if (_worker_warmup_cb)
+    {
+        _worker_warmup_cb();
+    }
+    auto active = true;
+    while (active)
+    {
+        try
+        {
+            active = process_next_msg();
+        }
+        catch (const std::exception &ex)
+        {
+            _err_handler(ex.what());
+        }
+        catch (...)
+        {
+            _err_handler("Unknown exeption in async logger worker loop.");
+        }
+    }
+    if (_worker_teardown_cb)
+    {
+        _worker_teardown_cb();
+    }
 }
 
 // process next message in the queue
 // return true if this thread should still be active (while no terminate msg was received)
 inline bool spdlog::details::async_log_helper::process_next_msg()
 {
-	async_msg incoming_async_msg;
-	bool dequeued = _q.dequeue_for(incoming_async_msg, std::chrono::milliseconds(1000));		
-	if (!dequeued)
-	{	
+    async_msg incoming_async_msg;
+    bool dequeued = _q.dequeue_for(incoming_async_msg, std::chrono::seconds(2));	
+    if (!dequeued)
+    {
+        handle_flush_interval();
+        return true;
+    }
+
+    switch (incoming_async_msg.msg_type)
+    {
+    case async_msg_type::flush:
+        flush_sinks();
+        return true;
+
+    case async_msg_type::terminate:
+        flush_sinks();
+        return false;
+
+    default:
+        log_msg incoming_log_msg;
+        incoming_async_msg.fill_log_msg(incoming_log_msg);
+        _formatter->format(incoming_log_msg);
+        for (auto &s : _sinks)
+        {
+            if (s->should_log(incoming_log_msg.level))
+            {
+                s->log(incoming_log_msg);
+            }
+        }
 		handle_flush_interval();
-		return true;
-	}
-	
-	switch (incoming_async_msg.msg_type)
-	{
-	case async_msg_type::flush:
-		flush_sinks();
-		return true;
-		
-
-	case async_msg_type::terminate:
-		//flush_sinks();
-		return false;
-		
-
-	default:
-		log_msg incoming_log_msg;
-		incoming_async_msg.fill_log_msg(incoming_log_msg);
-		_formatter->format(incoming_log_msg);
-		for (auto &s : _sinks)
-		{
-			if (s->should_log(incoming_log_msg.level))
-			{
-				s->log(incoming_log_msg);
-			}
-		}
-		return true;		
-	}
-	assert(false);
-	return true; // should not be reached
-
+        return true;
+    }
+    assert(false);
+    return true; // should not be reached
 }
 
-// flush all sinks if _flush_interval_ms has expired. only called if queue is empty
-inline void spdlog::details::async_log_helper::handle_flush_interval()
-{		
-	if (_flush_interval_ms == std::chrono::milliseconds::zero())
-	{
-		return;
-	}
-	auto delta = details::os::now() - _last_flush;;		
-	if (delta >= _flush_interval_ms)
-	{					
-		flush_sinks();
-	}
-}
 
 
 inline void spdlog::details::async_log_helper::set_formatter(formatter_ptr msg_formatter)
 {
-	_formatter = std::move(msg_formatter);
+    _formatter = std::move(msg_formatter);
 }
 
-
 inline void spdlog::details::async_log_helper::set_error_handler(spdlog::log_err_handler err_handler)
 {
-	_err_handler = std::move(err_handler);
+    _err_handler = std::move(err_handler);
 }
 
 
-// flush all sinks if _flush_interval_ms has expired. only called if queue is empty
-inline void spdlog::details::async_log_helper::flush_sinks()
+// flush all sinks if _flush_interval_ms has expired. 
+inline void spdlog::details::async_log_helper::handle_flush_interval()
 {
-	printf("FLUSH!\n");
-	for (auto &s : _sinks)
-	{
-		s->flush();
-	}
-	_last_flush = os::now();
+    if (_flush_interval_ms == std::chrono::milliseconds::zero())
+    {
+        return;
+    }
+    auto delta = details::os::now() - _last_flush;
+    ;
+    if (delta >= _flush_interval_ms)
+    {
+        flush_sinks();
+    }
 }
 
+// flush all sinks if _flush_interval_ms has expired. only called if queue is empty
+inline void spdlog::details::async_log_helper::flush_sinks()
+{    
+    for (auto &s : _sinks)
+    {
+        s->flush();
+    }
+    _last_flush = os::now();
+}

include/spdlog/details/mpmc_blocking_q.h

@@ -6,84 +6,79 @@
 //
 
 // async log helper :
-// multi producer-multi consumer blocking queue 
+// multi producer-multi consumer blocking queue
 // enqueue(..) - will block until room found to put the new message
 // enqueue_nowait(..) - will return immediatly with false if no room left in the queue
 // dequeue_for(..) - will block until the queue is not empty or timeout passed
 
-
 #include <condition_variable>
 #include <mutex>
 #include <queue>
 
-
 namespace spdlog {
-	namespace details {
-
-		template<typename T>
-		class mpmc_bounded_queue
-		{
-		public:
-
-			using item_type = T;
-			explicit mpmc_bounded_queue(size_t max_items) : max_items_(max_items) {}
-
-			// 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_.size() <= this->max_items_; });
-					q_.push(std::forward<T>(item));
-				}
-				push_cv_.notify_one();
-			}
-
-			// try to enqueue and return immdeialty false if no room left
-			bool enqueue_nowait(T &&item)
-			{
-				{
-					std::unique_lock<std::mutex> lock(queue_mutex_);
-					if (this->q_.size() >= this->max_items_)
-					{
-						return false;
-					}
-					q_.push(std::forward<T>(item));
-				}
-				push_cv_.notify_one();
-				return true;
-			}
-
-			// 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_);
-					//push_cv_.wait(lock, [this] {return this->q_.size() > 0; });
-					bool found_msg = push_cv_.wait_for(lock, wait_duration, [this] {return this->q_.size() > 0; });
-					if (!found_msg)
-					{
-						return false;
-					}
-					popped_item = std::move(q_.front());
-					q_.pop();
-				}
-				pop_cv_.notify_one();
-				return true;
-			}
-
-
-
-
-		private:
-			size_t max_items_;
-			std::mutex queue_mutex_;
-			std::condition_variable push_cv_;
-			std::condition_variable pop_cv_;
-
-			std::queue<T> q_;
-
-		};
-	}
-}
+namespace details {
+
+template<typename T>
+class mpmc_bounded_queue
+{
+public:
+    using item_type = T;
+    explicit mpmc_bounded_queue(size_t max_items)
+        : max_items_(max_items)
+    {
+    }
+
+    // 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_.size() < this->max_items_; });
+            q_.push(std::move(item));
+        }
+        push_cv_.notify_one();
+    }
+
+    // try to enqueue and return immdeialty false if no room left
+    bool enqueue_nowait(T &&item)
+    {
+        {
+            std::unique_lock<std::mutex> lock(queue_mutex_);
+            if (q_.size() == this->max_items_)
+            {
+                return false;
+            }
+            q_.push(std::forward<T>(item));
+        }
+        push_cv_.notify_one();
+        return true;
+    }
+
+    // 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_.size() > 0; }))
+            {
+                return false;
+            }
+
+            popped_item = std::move(q_.front());
+            q_.pop();
+        }
+        pop_cv_.notify_one();
+        return true;
+    }
+
+private:
+    size_t max_items_;
+    std::mutex queue_mutex_;
+    std::condition_variable push_cv_;
+    std::condition_variable pop_cv_;
+
+    std::queue<T> q_;
+};
+} // namespace details
+} // namespace spdlog

include/spdlog/sinks/test_sink.h

@@ -17,20 +17,19 @@ template<class Mutex>
 class test_sink : public base_sink<Mutex>
 {
 public:
-	size_t msg_counter() 
-	{ 
-		return msg_counter_; 
-	}
+    size_t msg_counter()
+    {
+        return msg_counter_;
+    }
 
 protected:
-    void _sink_it(const details::log_msg &) override 
-	{
-		msg_counter_++;				
-	}
+    void _sink_it(const details::log_msg &) override
+    {
+        msg_counter_++;
+    }
 
     void _flush() override {}
-	size_t msg_counter_{ 0 };
-
+    size_t msg_counter_{0};
 };
 
 using test_sink_mt = test_sink<std::mutex>;