1 files changed, 333 insertions, 0 deletions
diff --git a/lib/spdlog/details/async_log_helper.h b/lib/spdlog/details/async_log_helper.h
new file mode 100644
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+++ b/lib/spdlog/details/async_log_helper.h
@@ -0,0 +1,333 @@
+//
+// Copyright(c) 2015 Gabi Melman.
+// Distributed under the MIT License (http://opensource.org/licenses/MIT)
+//
+
+// async log helper :
+// Process logs asynchronously using a back thread.
+//
+// If the internal queue of log messages reaches its max size,
+// then the client call will block until there is more room.
+//
+
+#pragma once
+
+#include "../common.h"
+#include "../details/log_msg.h"
+#include "../details/mpmc_blocking_q.h"
+#include "../details/os.h"
+#include "../formatter.h"
+#include "../sinks/sink.h"
+
+#include <chrono>
+#include <condition_variable>
+#include <exception>
+#include <functional>
+#include <memory>
+#include <string>
+#include <thread>
+#include <utility>
+#include <vector>
+
+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
+    {
+        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) = default;
+        async_msg &operator=(async_msg &&other) = default;
+
+        // 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)
+        {
+        }
+
+        // copy into log_msg
+        void fill_log_msg(log_msg &msg, std::string *logger_name)
+        {
+            msg.logger_name = logger_name;
+            msg.level = level;
+            msg.time = time;
+            msg.thread_id = thread_id;
+            msg.raw.clear();
+            msg.raw << txt;
+            msg.msg_id = msg_id;
+        }
+    };
+
+public:
+    using item_type = async_msg;
+    using q_type = details::mpmc_bounded_queue<item_type>;
+
+    using clock = std::chrono::steady_clock;
+
+    async_log_helper(std::string logger_name, 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);
+
+    // 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;
+
+    void set_formatter(formatter_ptr msg_formatter);
+
+    void flush();
+
+    void set_error_handler(spdlog::log_err_handler err_handler);
+
+private:
+    std::string _logger_name;
+    formatter_ptr _formatter;
+    std::vector<std::shared_ptr<sinks::sink>> _sinks;
+
+    // queue of messages to log
+    q_type _q;
+
+    log_err_handler _err_handler;
+
+    std::chrono::time_point<log_clock> _last_flush;
+
+    // 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;
+
+    // auto periodic sink flush parameter
+    const std::chrono::milliseconds _flush_interval_ms;
+
+    // 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_;
+
+    // worker thread
+    std::thread _worker_thread;
+
+    void enqueue_msg(async_msg &&new_msg, async_overflow_policy policy);
+
+    // 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();
+
+    void handle_flush_interval();
+
+    void flush_sinks();
+};
+} // namespace details
+} // namespace spdlog
+
+///////////////////////////////////////////////////////////////////////////////
+// async_sink class implementation
+///////////////////////////////////////////////////////////////////////////////
+inline spdlog::details::async_log_helper::async_log_helper(std::string logger_name, 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)
+    : _logger_name(std::move(logger_name))
+    , _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);
+}
+
+// send to the worker thread terminate message, and join it.
+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 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);
+}
+
+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));
+    }
+}
+
+// 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);
+}
+
+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();
+        }
+        SPDLOG_CATCH_AND_HANDLE
+    }
+    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::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, &_logger_name);
+        _formatter->format(incoming_log_msg);
+        for (auto &s : _sinks)
+        {
+            if (s->should_log(incoming_log_msg.level))
+            {
+                try
+                {
+                    s->log(incoming_log_msg);
+                }
+                SPDLOG_CATCH_AND_HANDLE
+            }
+        }
+        handle_flush_interval();
+        return true;
+    }
+    assert(false);
+    return true; // should not be reached
+}
+
+inline void spdlog::details::async_log_helper::set_formatter(formatter_ptr 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);
+}
+
+// flush all sinks if _flush_interval_ms has expired.
+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();
+    }
+}
+
+// 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)
+    {
+        try
+        {
+            s->flush();
+        }
+        SPDLOG_CATCH_AND_HANDLE
+    }
+    _last_flush = os::now();
+}