threadpool.hxx

Go to the documentation of this file.

/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
/*
 * This file is part of the LibreOffice project.
 *
 * 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 INCLUDED_COMPHELPER_THREADPOOL_HXX
#define INCLUDED_COMPHELPER_THREADPOOL_HXX
 
#include <sal/config.h>
#include <rtl/ref.hxx>
#include <comphelper/comphelperdllapi.h>
#include <mutex>
#include <condition_variable>
#include <cstddef>
#include <vector>
#include <memory>
 
namespace comphelper
{
class ThreadTaskTag;
 
class COMPHELPER_DLLPUBLIC ThreadTask
{
friend class ThreadPool;
friend struct std::default_delete<ThreadTask>;
    std::shared_ptr<ThreadTaskTag>  mpTag;
 
    void      exec();
protected:
    virtual void doWork() = 0;
    virtual   ~ThreadTask() {}
public:
    ThreadTask(std::shared_ptr<ThreadTaskTag> pTag);
};
 
class COMPHELPER_DLLPUBLIC ThreadPool final
{
public:
    static      ThreadPool& getSharedOptimalPool();
 
    static std::shared_ptr<ThreadTaskTag> createThreadTaskTag();
 
    static bool isTaskTagDone(const std::shared_ptr<ThreadTaskTag>&);
 
    static      std::size_t getPreferredConcurrency();
 
    ThreadPool( std::size_t nWorkers );
    ~ThreadPool();
 
    void        pushTask( std::unique_ptr<ThreadTask> pTask);
 
    void        waitUntilDone(const std::shared_ptr<ThreadTaskTag>&, bool bJoin = true);
 
    void        joinThreadsIfIdle();
 
    bool        isIdle() const { return maTasks.empty() && mnBusyWorkers == 0; };
 
    sal_Int32   getWorkerCount() const { return mnMaxWorkers; }
 
    void        shutdown();
 
private:
    ThreadPool(const ThreadPool&) = delete;
    ThreadPool& operator=(const ThreadPool&) = delete;
 
    class ThreadWorker;
    friend class ThreadWorker;
 
    std::unique_ptr<ThreadTask> popWorkLocked( std::unique_lock< std::mutex > & rGuard, bool bWait );
    void shutdownLocked(std::unique_lock<std::mutex>&);
    void incBusyWorker();
    void decBusyWorker();
 
    std::mutex              maMutex;
    std::condition_variable maTasksChanged;
    bool                    mbTerminate;
    std::size_t const       mnMaxWorkers;
    std::size_t             mnBusyWorkers;
    std::vector< std::unique_ptr<ThreadTask> >   maTasks;
    std::vector< rtl::Reference< ThreadWorker > > maWorkers;
};
 
} // namespace comphelper
 
#endif // INCLUDED_COMPHELPER_THREADPOOL_HXX
 
/* vim:set shiftwidth=4 softtabstop=4 expandtab: */