qtconcurrentrunbase.h

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/****************************************************************************
**
** Copyright (C) 2016 The Qt Company Ltd.
** Contact: https://www.qt.io/licensing/
**
** This file is part of the QtConcurrent module of the Qt Toolkit.
**
** $QT_BEGIN_LICENSE:LGPL$
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** accordance with the commercial license agreement provided with the
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** Alternatively, this file may be used under the terms of the GNU
** General Public License version 2.0 or (at your option) the GNU General
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****************************************************************************/

#ifndef QTCONCURRENT_RUNBASE_H
#define QTCONCURRENT_RUNBASE_H

#include <QtConcurrent/qtconcurrent_global.h>

#ifndef QT_NO_CONCURRENT

#include <QtCore/qfuture.h>
#include <QtCore/qrunnable.h>
#include <QtCore/qthreadpool.h>

QT_BEGIN_NAMESPACE


#ifndef Q_QDOC

namespace QtConcurrent {

template <typename T>
struct SelectSpecialization
{
    template <class Normal, class Void>
    struct Type { typedef Normal type; };
};

template <>
struct SelectSpecialization<void>
{
    template <class Normal, class Void>
    struct Type { typedef Void type; };
};

template <typename T>
class RunFunctionTaskBase : public QFutureInterface<T> , public QRunnable
{
public:
    QFuture<T> start()
    {
        return start(QThreadPool::globalInstance());
    }

    QFuture<T> start(QThreadPool *pool)
    {
        this->setThreadPool(pool);
        this->setRunnable(this);
        this->reportStarted();
        QFuture<T> theFuture = this->future();
        pool->start(this, /*m_priority*/ 0);
        return theFuture;
    }

    void run() override {}
    virtual void runFunctor() = 0;
};

template <typename T>
class RunFunctionTask : public RunFunctionTaskBase<T>
{
public:
    void run() override
    {
        if (this->isCanceled()) {
            this->reportFinished();
            return;
        }
#ifndef QT_NO_EXCEPTIONS
        try {
#endif
            this->runFunctor();
#ifndef QT_NO_EXCEPTIONS
        } catch (QException &e) {
            QFutureInterface<T>::reportException(e);
        } catch (...) {
            QFutureInterface<T>::reportException(QUnhandledException());
        }
#endif

        this->reportResult(result);
        this->reportFinished();
    }
    T result;
};

template <>
class RunFunctionTask<void> : public RunFunctionTaskBase<void>
{
public:
    void run() override
    {
        if (this->isCanceled()) {
            this->reportFinished();
            return;
        }
#ifndef QT_NO_EXCEPTIONS
        try {
#endif
            this->runFunctor();
#ifndef QT_NO_EXCEPTIONS
        } catch (QException &e) {
            QFutureInterface<void>::reportException(e);
        } catch (...) {
            QFutureInterface<void>::reportException(QUnhandledException());
        }
#endif
        this->reportFinished();
    }
};

} //namespace QtConcurrent

#endif //Q_QDOC

QT_END_NAMESPACE

#endif // QT_NO_CONCURRENT

#endif