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/***************************************************************************
* Copyright (C) 2010 by Peter Penz <[email protected]> *
* *
* 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 of the License, 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. *
* *
* You should have received a copy of the GNU General Public License *
* along with this program; if not, write to the *
* Free Software Foundation, Inc., *
* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA *
***************************************************************************/
#ifndef PENDINGTHREADSMAINTAINER_H
#define PENDINGTHREADSMAINTAINER_H
#include <libdolphin_export.h>
#include <QObject>
class QTimer;
/**
* If the creator of a thread gets deleted, although the thread is still
* working, usually QThread::wait() is invoked. The drawback of this
* approach is that the user interface gets blocked for an undefined amount
* of time. If the thread does not contain references to the creator, the
* deleting can be forwarded to the PendingThreadsMaintainer. In the following
* example it is assumed, that m_thread will be 0, if it has been deleted by the
* creator after receiving the signal QThread::finished():
*
* \code
* ThreadCreator::~ThreadCreator()
* {
* if (m_thread) {
* PendingThreadsMaintainer::instance().append(m_thread);
* m_thread = 0;
* }
* }
* \endcode
*
* The thread will get automatically deleted after it (or has already) been finished.
*
* Implementation note: Connecting to the signal QThread::finished() is
* not sufficient, as it is possible that the thread has already emitted
* the signal, but the signal has not been received yet by the thread creator.
* Because of this a polling is done each 5 seconds to check, whether the
* thread has been finished.
*/
class LIBDOLPHINPRIVATE_EXPORT PendingThreadsMaintainer : public QObject
{
Q_OBJECT
public:
static PendingThreadsMaintainer& instance();
virtual ~PendingThreadsMaintainer();
/**
* Appends the thread \p thread to the maintainer. The thread
* will be deleted by the maintainer after it has been finished.
*/
void append(QThread* thread);
protected:
PendingThreadsMaintainer();
private slots:
void cleanup();
private:
QList<QThread*> m_threads;
QTimer* m_timer;
friend class PendingThreadsMaintainerSingleton;
};
#endif
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