workerobject.h

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/* ============================================================
 *
 * This file is a part of digiKam project
 * https://www.digikam.org
 *
 * Date        : 2010-04-06
 * Description : Multithreaded worker object
 *
 * Copyright (C) 2010-2012 by Marcel Wiesweg <marcel dot wiesweg at gmx dot de>
 * Copyright (C) 2012-2022 by Gilles Caulier <caulier dot gilles at gmail dot com>
 *
 * This program is free software; you can redistribute it
 * and/or modify it under the terms of the GNU General
 * Public License as published by the Free Software Foundation;
 * either version 2, or (at your option)
 * any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * ============================================================ */
 
#ifndef DIGIKAM_WORKER_OBJECT_H
#define DIGIKAM_WORKER_OBJECT_H
 
// Qt includes
 
#include <QObject>
#include <QThread>
 
// Local includes
 
#include "digikam_export.h"
 
class QEventLoop;
 
namespace Digikam
{
 
class WorkerObjectRunnable;
 
class DIGIKAM_EXPORT WorkerObject : public QObject
{
    Q_OBJECT
 
public:
 
    enum State
    {
        Inactive,
        Scheduled,
        Running,
        Deactivating
    };
 
    enum DeactivatingMode
    {
        FlushSignals,               
        KeepSignals,                
        PhaseOut                    
    };
 
public:
 
    explicit WorkerObject();
    ~WorkerObject()                       override;
 
    State state()                   const;
 
    void wait();
 
    void setPriority(QThread::Priority priority);
    QThread::Priority priority()    const;
 
    bool connectAndSchedule(const QObject* sender,
                            const char* signal,
                            const char* method,
                            Qt::ConnectionType type = Qt::AutoConnection) const;
 
    static bool connectAndSchedule(const QObject* sender,
                                   const char* signal,
                                   const WorkerObject* receiver,
                                   const char* method,
                                   Qt::ConnectionType type = Qt::AutoConnection);
 
    static bool disconnectAndSchedule(const QObject* sender,
                                      const char* signal,
                                      const WorkerObject* receiver,
                                      const char* method);
 
public Q_SLOTS:
 
    void schedule();
 
    void deactivate(DeactivatingMode mode = FlushSignals);
 
Q_SIGNALS:
 
    void started();
    void finished();
 
protected:
 
    bool transitionToRunning();
    void transitionToInactive();
 
    void run();
    void setEventLoop(QEventLoop* loop);
    void addRunnable(WorkerObjectRunnable* loop);
    void removeRunnable(WorkerObjectRunnable* loop);
 
    void shutDown();
 
    virtual void aboutToQuitLoop();
 
    virtual void aboutToDeactivate();
 
    bool event(QEvent* e)                 override;
 
private:
 
    friend class WorkerObjectRunnable;
    friend class ThreadManager;
 
private:
 
    // Disable.
    WorkerObject(const WorkerObject&)            = delete;
    WorkerObject& operator=(const WorkerObject&) = delete;
    WorkerObject(QObject*)                       = delete;
 
private:
 
    class Private;
    Private* const d;
};
 
} // namespace Digikam
 
#endif // DIGIKAM_WORKER_OBJECT_H