Quelle threadpool.hxx Sprache: C

/* -*- 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;

    /// execute this task
    void      exec();
protected:
    /// override to get your task performed by the pool
    virtual void doWork() = 0;
    /// once pushed ThreadTasks are destroyed by the pool
    virtual   ~ThreadTask() {}
public:
    ThreadTask(std::shared_ptr<ThreadTaskTag> pTag);
};

/// A very basic thread-safe thread pool implementation
class COMPHELPER_DLLPUBLIC ThreadPool final
{
public:
    /// returns a pointer to a shared pool with optimal thread
    /// count for the CPU
    static      ThreadPool& getSharedOptimalPool();

    static std::shared_ptr<ThreadTaskTag> createThreadTaskTag();

    static bool isTaskTagDone(const std::shared_ptr<ThreadTaskTag>&);

    /// returns a configurable max-concurrency
    /// limit to avoid spawning an unnecessarily
    /// large number of threads on high-core boxes.
    /// MAX_CONCURRENCY env. var. controls the cap.
    static      std::size_t getPreferredConcurrency();

    ThreadPool( std::size_t nWorkers );
    ~ThreadPool();

    /// push a new task onto the work queue
    void        pushTask( std::unique_ptr<ThreadTask> pTask);

    /** Wait until all queued tasks associated with the tag are completed
        @param  bJoin - if set call joinThreadsIfIdle() at the end
    */
    void        waitUntilDone(const std::shared_ptr<ThreadTaskTag>&, bool bJoin =
#if defined EMSCRIPTEN
                                                                     false
#else
                                                                     true
#endif
                             );

    /// join all threads if there are no tasks presently.
    /// return false if !isIdle()
    bool        joinThreadsIfIdle();

    /// return true if there are no queued or worked-on tasks
    bool        isIdle() const { return maTasks.empty() && mnBusyWorkers == 0; };

    /// return the number of live worker threads
    sal_Int32   getWorkerCount() const { return mnMaxWorkers; }

    /// wait until all work is completed, then join all threads
    void        shutdown();

private:
    ThreadPool(const ThreadPool&) = delete;
    ThreadPool& operator=(const ThreadPool&) = delete;

    class ThreadWorker;
    friend class ThreadWorker;

    /** Pop a work task
        @param  bWait - if set wait until task present or termination
        @return a new task to perform, or NULL if list empty or terminated
    */
    std::unique_ptr<ThreadTask> popWorkLocked( std::unique_lock< std::mutex > & rGuard, bool bWait );
    void shutdownLocked(std::unique_lock<std::mutex>&);
    void incBusyWorker();
    void decBusyWorker();

    /// signalled when all in-progress tasks are complete
    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: */

quality100%

¤ Dauer der Verarbeitung: 0.33 Sekunden (vorverarbeitet) ¤

Wurzel

Suchen

Beweissystem der NASA

Beweissystem Isabelle

NIST Cobol Testsuite

Cephes Mathematical Library

Wiener Entwicklungsmethode

Haftungshinweis

Die Informationen auf dieser Webseite wurden nach bestem Wissen sorgfältig zusammengestellt. Es wird jedoch weder Vollständigkeit, noch Richtigkeit, noch Qualität der bereit gestellten Informationen zugesichert.

Bemerkung:

Die farbliche Syntaxdarstellung ist noch experimentell.