periodic_worker.h

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