http_thread_pool.h

Go to the documentation of this file.

// Copyright (C) 2021 Internet Systems Consortium, Inc. ("ISC")
//
// This Source Code Form is subject to the terms of the Mozilla Public
// License, v. 2.0. If a copy of the MPL was not distributed with this
// file, You can obtain one at http://mozilla.org/MPL/2.0/.

#ifndef HTTP_THREAD_POOL_H
#define HTTP_THREAD_POOL_H

#include <asiolink/io_service.h>
#include <util/unlock_guard.h>

#include <boost/shared_ptr.hpp>

#include <condition_variable>
#include <list>
#include <mutex>
#include <thread>

namespace isc {
namespace http {

class HttpThreadPool {
public:
    enum class State {
        STOPPED,    
        RUNNING,    
        PAUSED,     
    };

    HttpThreadPool(asiolink::IOServicePtr io_service, size_t pool_size,
                   bool defer_start = false);

    ~HttpThreadPool();

    void run();

    void pause();

    void stop();

    bool isRunning() {
        return (getState() == State::RUNNING);
    }

    bool isPaused() {
        return (getState() == State::PAUSED);
    }

    bool isStopped() {
        return (getState() == State::STOPPED);
    }

private:
    void setState(State state);

    State getState();

    bool validateStateChange(State state) const;

    void threadWork();

public:
    asiolink::IOServicePtr getIOService() const;

    uint16_t getPoolSize() const;

    uint16_t getThreadCount() const;

private:
    size_t pool_size_;

    asiolink::IOServicePtr io_service_;

    State run_state_;

    std::mutex mutex_;

    std::condition_variable thread_cv_;

    std::condition_variable main_cv_;

    size_t paused_;

    size_t running_;

    size_t exited_;

    std::list<boost::shared_ptr<std::thread> > threads_;
};

typedef boost::shared_ptr<HttpThreadPool> HttpThreadPoolPtr;

} // end of namespace isc::http
} // end of namespace isc

#endif