THUAI6/CAPI/cpp/spdlog/include/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
        };

        // Async msg to move to/from the queue
        // Movable only. should never be copied
        struct async_msg : log_msg_buffer
        {
            async_msg_type msg_type{async_msg_type::log};
            async_logger_ptr worker_ptr;

            async_msg() = default;
            ~async_msg() = default;

            // should only be moved in or out of the queue..
            async_msg(const async_msg&) = delete;

// support for vs2013 move
#if defined(_MSC_VER) && _MSC_VER <= 1800
            async_msg(async_msg&& other) :
                log_msg_buffer(std::move(other)),
                msg_type(other.msg_type),
                worker_ptr(std::move(other.worker_ptr))
            {
            }

            async_msg& operator=(async_msg&& other)
            {
                *static_cast<log_msg_buffer*>(this) = std::move(other);
                msg_type = other.msg_type;
                worker_ptr = std::move(other.worker_ptr);
                return *this;
            }
#else  // (_MSC_VER) && _MSC_VER <= 1800
            async_msg(async_msg&&) = default;
            async_msg& operator=(async_msg&&) = default;
#endif

            // construct from log_msg with given type
            async_msg(async_logger_ptr&& worker, async_msg_type the_type, const details::log_msg& m) :
                log_msg_buffer{m},
                msg_type{the_type},
                worker_ptr{std::move(worker)}
            {
            }

            async_msg(async_logger_ptr&& worker, async_msg_type the_type) :
                log_msg_buffer{},
                msg_type{the_type},
                worker_ptr{std::move(worker)}
            {
            }

            explicit async_msg(async_msg_type the_type) :
                async_msg{nullptr, the_type}
            {
            }
        };

        class SPDLOG_API thread_pool
        {
        public:
            using item_type = async_msg;
            using q_type = details::mpmc_blocking_queue<item_type>;

            thread_pool(size_t q_max_items, size_t threads_n, std::function<void()> on_thread_start, std::function<void()> on_thread_stop);
            thread_pool(size_t q_max_items, size_t threads_n, std::function<void()> on_thread_start);
            thread_pool(size_t q_max_items, size_t threads_n);

            // message all threads to terminate gracefully and join them
            ~thread_pool();

            thread_pool(const thread_pool&) = delete;
            thread_pool& operator=(thread_pool&&) = delete;

            void post_log(async_logger_ptr&& worker_ptr, const details::log_msg& msg, async_overflow_policy overflow_policy);
            void post_flush(async_logger_ptr&& worker_ptr, async_overflow_policy overflow_policy);
            size_t overrun_counter();
            void reset_overrun_counter();
            size_t queue_size();

        private:
            q_type q_;

            std::vector<std::thread> threads_;

            void post_async_msg_(async_msg&& new_msg, async_overflow_policy overflow_policy);
            void worker_loop_();

            // process next message in the queue
            // return true if this thread should still be active (while no terminate msg
            // was received)
            bool process_next_msg_();
        };

    }  // namespace details
}  // namespace spdlog

#ifdef SPDLOG_HEADER_ONLY
#include "thread_pool-inl.h"
#endif