/****************************************************************************
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** Copyright (C) 2012 Nokia Corporation and/or its subsidiary(-ies).
** Contact: http://www.qt-project.org/
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** This file is part of the QtCore module of the Qt Toolkit.
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** GNU Lesser General Public License Usage
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** License version 2.1 as published by the Free Software Foundation and
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** file. Please review the following information to ensure the GNU Lesser
** General Public License version 2.1 requirements will be met:
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** rights. These rights are described in the Nokia Qt LGPL Exception
** version 1.1, included in the file LGPL_EXCEPTION.txt in this package.
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** Alternatively, this file may be used under the terms of the GNU General
** Public License version 3.0 as published by the Free Software Foundation
** and appearing in the file LICENSE.GPL included in the packaging of this
** file. Please review the following information to ensure the GNU General
** Public License version 3.0 requirements will be met:
** http://www.gnu.org/copyleft/gpl.html.
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** Alternatively, this file may be used in accordance with the terms and
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** $QT_END_LICENSE$
**
****************************************************************************/

#ifndef QFUTUREWATCHER_H
#define QFUTUREWATCHER_H

#include <QtConcurrent/qtconcurrent_global.h>

#include <QtConcurrent/qfuture.h>

#ifndef QT_NO_QFUTURE

#include <QtCore/qobject.h>

QT_BEGIN_HEADER
QT_BEGIN_NAMESPACE


class QEvent;

class QFutureWatcherBasePrivate;
class Q_CONCURRENT_EXPORT QFutureWatcherBase : public QObject
{
    Q_OBJECT
    Q_DECLARE_PRIVATE(QFutureWatcherBase)

public:
    explicit QFutureWatcherBase(QObject *parent = 0);

    int progressValue() const;
    int progressMinimum() const;
    int progressMaximum() const;
    QString progressText() const;

    bool isStarted() const;
    bool isFinished() const;
    bool isRunning() const;
    bool isCanceled() const;
    bool isPaused() const;

    void waitForFinished();

    void setPendingResultsLimit(int limit);

    bool event(QEvent *event);

Q_SIGNALS:
    void started();
    void finished();
    void canceled();
    void paused();
    void resumed();
    void resultReadyAt(int resultIndex);
    void resultsReadyAt(int beginIndex, int endIndex);
    void progressRangeChanged(int minimum, int maximum);
    void progressValueChanged(int progressValue);
    void progressTextChanged(const QString &progressText);

public Q_SLOTS:
    void cancel();
    void setPaused(bool paused);
    void pause();
    void resume();
    void togglePaused();

protected:
    void connectNotify (const QMetaMethod &signal);
    void disconnectNotify (const QMetaMethod &signal);

    // called from setFuture() implemented in template sub-classes
    void connectOutputInterface();
    void disconnectOutputInterface(bool pendingAssignment = false);

private:
    // implemented in the template sub-classes
    virtual const QFutureInterfaceBase &futureInterface() const = 0;
    virtual QFutureInterfaceBase &futureInterface() = 0;
};

template <typename T>
class QFutureWatcher : public QFutureWatcherBase
{
public:
    explicit QFutureWatcher(QObject *_parent = 0)
        : QFutureWatcherBase(_parent)
    { }
    ~QFutureWatcher()
    { disconnectOutputInterface(); }

    void setFuture(const QFuture<T> &future);
    QFuture<T> future() const
    { return m_future; }

    T result() const { return m_future.result(); }
    T resultAt(int index) const { return m_future.resultAt(index); }

#ifdef qdoc
    int progressValue() const;
    int progressMinimum() const;
    int progressMaximum() const;
    QString progressText() const;

    bool isStarted() const;
    bool isFinished() const;
    bool isRunning() const;
    bool isCanceled() const;
    bool isPaused() const;

    void waitForFinished();

    void setPendingResultsLimit(int limit);

Q_SIGNALS:
    void started();
    void finished();
    void canceled();
    void paused();
    void resumed();
    void resultReadyAt(int resultIndex);
    void resultsReadyAt(int beginIndex, int endIndex);
    void progressRangeChanged(int minimum, int maximum);
    void progressValueChanged(int progressValue);
    void progressTextChanged(const QString &progressText);

public Q_SLOTS:
    void cancel();
    void setPaused(bool paused);
    void pause();
    void resume();
    void togglePaused();
#endif

private:
    QFuture<T> m_future;
    const QFutureInterfaceBase &futureInterface() const { return m_future.d; }
    QFutureInterfaceBase &futureInterface() { return m_future.d; }
};

template <typename T>
Q_INLINE_TEMPLATE void QFutureWatcher<T>::setFuture(const QFuture<T> &_future)
{
    if (_future == m_future)
        return;

    disconnectOutputInterface(true);
    m_future = _future;
    connectOutputInterface();
}

template <>
class QFutureWatcher<void> : public QFutureWatcherBase
{
public:
    explicit QFutureWatcher(QObject *_parent = 0)
        : QFutureWatcherBase(_parent)
    { }
    ~QFutureWatcher()
    { disconnectOutputInterface(); }

    void setFuture(const QFuture<void> &future);
    QFuture<void> future() const
    { return m_future; }

private:
    QFuture<void> m_future;
    const QFutureInterfaceBase &futureInterface() const { return m_future.d; }
    QFutureInterfaceBase &futureInterface() { return m_future.d; }
};

Q_INLINE_TEMPLATE void QFutureWatcher<void>::setFuture(const QFuture<void> &_future)
{
    if (_future == m_future)
        return;

    disconnectOutputInterface(true);
    m_future = _future;
    connectOutputInterface();
}

QT_END_NAMESPACE
QT_END_HEADER

#endif // QT_NO_CONCURRENT

#endif // QFUTUREWATCHER_H