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#include "qfuturewatcher.h"

#ifndef QT_NO_QFUTURE

#include <QtCore/qcoreevent.h>

#include <QtCore/qcoreapplication.h>

#include <QtCore/qthread.h>

#include "qfuturewatcher_p.h"

QT_BEGIN_NAMESPACE

/*! \class QFutureWatcher

    \reentrant

    \since 4.4

    \ingroup thread

    \brief The QFutureWatcher class allows monitoring a QFuture using signals

    and slots.

    QFutureWatcher provides information and notifications about a QFuture. Use

    the setFuture() function to start watching a particular QFuture. The

    future() function returns the future set with setFuture().

    For convenience, several of QFuture's functions are also available in

    QFutureWatcher: progressValue(), progressMinimum(), progressMaximum(),

    progressText(), isStarted(), isFinished(), isRunning(), isCanceled(),

    isPaused(), waitForFinished(), result(), and resultAt(). The cancel(),

    setPaused(), pause(), resume(), and togglePaused() functions are slots in

    QFutureWatcher.

    Status changes are reported via the started(), finished(), canceled(),

    paused(), resumed(), resultReadyAt(), and resultsReadyAt() signals.

    Progress information is provided from the progressRangeChanged(),

    void progressValueChanged(), and progressTextChanged() signals.

    Throttling control is provided by the setPendingResultsLimit() function.

    When the number of pending resultReadyAt() or resultsReadyAt() signals

    exceeds the limit, the computation represented by the future will be

    throttled automatically. The computation will resume once the number of

    pending signals drops below the limit.

    Example: Starting a computation and getting a slot callback when it's

    finished:

    \snippet doc/src/snippets/code/src_corelib_concurrent_qfuturewatcher.cpp 0

    Be aware that not all asynchronous computations can be canceled or paused.

    For example, the future returned by QtConcurrent::run() cannot be

    canceled; but the future returned by QtConcurrent::mappedReduced() can.

    QFutureWatcher<void> is specialized to not contain any of the result

    fetching functions. Any QFuture<T> can be watched by a

    QFutureWatcher<void> as well. This is useful if only status or progress

    information is needed; not the actual result data.

    \sa QFuture, {Concurrent Programming}{Qt Concurrent}

*/

/*! \fn QFutureWatcher::QFutureWatcher(QObject *parent)

    Constructs a new QFutureWatcher with the given \a parent.

*/

QFutureWatcherBase::QFutureWatcherBase(QObject *parent)

    :QObject(*new QFutureWatcherBasePrivate, parent)

{ }

/*! \fn QFutureWatcher::~QFutureWatcher()

    Destroys the QFutureWatcher.

*/

/*! \fn void QFutureWatcher::cancel()

    Cancels the asynchronous computation represented by the future(). Note that

    the cancelation is asynchronous. Use waitForFinished() after calling

    cancel() when you need synchronous cancelation.

    Currently available results may still be accessed on a canceled QFuture,

    but new results will \e not become available after calling this function.

    Also, this QFutureWatcher will not deliver progress and result ready

    signals once canceled. This includes the progressValueChanged(),

    progressRangeChanged(), progressTextChanged(), resultReadyAt(), and

    resultsReadyAt() signals.

    Be aware that not all asynchronous computations can be canceled. For

    example, the QFuture returned by QtConcurrent::run() cannot be canceled;

    but the QFuture returned by QtConcurrent::mappedReduced() can.

*/

void QFutureWatcherBase::cancel()

{

    futureInterface().cancel();

}

/*! \fn void QFutureWatcher::setPaused(bool paused)

    If \a paused is true, this function pauses the asynchronous computation

    represented by the future(). If the computation is already paused, this

    function does nothing. This QFutureWatcher will stop delivering progress

    and result ready signals while the future is paused. Signal delivery will

    continue once the computation is resumed.

    If \a paused is false, this function resumes the asynchronous computation.

    If the computation was not previously paused, this function does nothing.

    Be aware that not all computations can be paused. For example, the

    QFuture returned by QtConcurrent::run() cannot be paused; but the QFuture

    returned by QtConcurrent::mappedReduced() can.

    \sa pause(), resume(), togglePaused()

*/

void QFutureWatcherBase::setPaused(bool paused)

{

    futureInterface().setPaused(paused);

}

/*! \fn void QFutureWatcher::pause()

    Pauses the asynchronous computation represented by the future(). This is a

    convenience method that simply calls setPaused(true).

    \sa resume()

*/

void QFutureWatcherBase::pause()

{

    futureInterface().setPaused(true);

}

/*! \fn void QFutureWatcher::resume()

    Resumes the asynchronous computation represented by the future(). This is

    a convenience method that simply calls setPaused(false).

    \sa pause()

*/

void QFutureWatcherBase::resume()

{

    futureInterface().setPaused(false);

}

/*! \fn void QFutureWatcher::togglePaused()

    Toggles the paused state of the asynchronous computation. In other words,

    if the computation is currently paused, calling this function resumes it;

    if the computation is running, it becomes paused. This is a convenience

    method for calling setPaused(!isPaused()).

    \sa setPaused(), pause(), resume()

*/

void QFutureWatcherBase::togglePaused()

{

    futureInterface().togglePaused();

}

/*! \fn int QFutureWatcher::progressValue() const

    Returns the current progress value, which is between the progressMinimum()

    and progressMaximum().

    \sa progressMinimum(), progressMaximum()

*/

int QFutureWatcherBase::progressValue() const

{

    return futureInterface().progressValue();

}

/*! \fn int QFutureWatcher::progressMinimum() const

    Returns the minimum progressValue().

    \sa progressValue(), progressMaximum()

*/

int QFutureWatcherBase::progressMinimum() const

{

    return futureInterface().progressMinimum();

}

/*! \fn int QFutureWatcher::progressMaximum() const

    Returns the maximum progressValue().

    \sa progressValue(), progressMinimum()

*/

int QFutureWatcherBase::progressMaximum() const

{

    return futureInterface().progressMaximum();

}

/*! \fn QString QFutureWatcher::progressText() const

    Returns the (optional) textual representation of the progress as reported

    by the asynchronous computation.

    Be aware that not all computations provide a textual representation of the

    progress, and as such, this function may return an empty string.

*/

QString QFutureWatcherBase::progressText() const

{

    return futureInterface().progressText();

}

/*! \fn bool QFutureWatcher::isStarted() const

    Returns true if the asynchronous computation represented by the future()

    has been started; otherwise returns false.

*/

bool QFutureWatcherBase::isStarted() const

{

    return futureInterface().queryState(QFutureInterfaceBase::Started);

}

/*! \fn bool QFutureWatcher::isFinished() const

    Returns true if the asynchronous computation represented by the future()

    has finished; otherwise returns false.

*/

bool QFutureWatcherBase::isFinished() const

{

    Q_D(const QFutureWatcherBase);

    return d->finished;

}

/*! \fn bool QFutureWatcher::isRunning() const

    Returns true if the asynchronous computation represented by the future()

    is currently running; otherwise returns false.

*/

bool QFutureWatcherBase::isRunning() const

{

    return futureInterface().queryState(QFutureInterfaceBase::Running);

}

/*! \fn bool QFutureWatcher::isCanceled() const

    Returns true if the asynchronous computation has been canceled with the

    cancel() function; otherwise returns false.

    Be aware that the computation may still be running even though this

    function returns true. See cancel() for more details.

*/

bool QFutureWatcherBase::isCanceled() const

{

    return futureInterface().queryState(QFutureInterfaceBase::Canceled);

}

/*! \fn bool QFutureWatcher::isPaused() const

    Returns true if the asynchronous computation has been paused with the

    pause() function; otherwise returns false.

    Be aware that the computation may still be running even though this

    function returns true. See setPaused() for more details.

    \sa setPaused(), togglePaused()

*/

bool QFutureWatcherBase::isPaused() const

{

    return futureInterface().queryState(QFutureInterfaceBase::Paused);

}

/*! \fn void QFutureWatcher::waitForFinished()

    Waits for the asynchronous computation to finish (including cancel()ed

    computations).

*/

void QFutureWatcherBase::waitForFinished()

{

    futureInterface().waitForFinished();

}

/*! \fn void QFutureWatcher::setPendingResultsLimit(int limit)

    The setPendingResultsLimit() provides throttling control. When the number

    of pending resultReadyAt() or resultsReadyAt() signals exceeds the

    \a limit, the computation represented by the future will be throttled

    automatically. The computation will resume once the number of pending

    signals drops below the \a limit.

*/

bool QFutureWatcherBase::event(QEvent *event)

{

    Q_D(QFutureWatcherBase);

    if (event->type() == QEvent::FutureCallOut) {

        QFutureCallOutEvent *callOutEvent = static_cast<QFutureCallOutEvent *>(event);

        if (futureInterface().isPaused()) {

            d->pendingCallOutEvents.append(callOutEvent->clone());

            return true;

        }

        if (callOutEvent->callOutType == QFutureCallOutEvent::Resumed

            && !d->pendingCallOutEvents.isEmpty()) {

            // send the resume

            d->sendCallOutEvent(callOutEvent);

            // next send all pending call outs

            for (int i = 0; i < d->pendingCallOutEvents.count(); ++i)

                d->sendCallOutEvent(d->pendingCallOutEvents.at(i));

            qDeleteAll(d->pendingCallOutEvents);

            d->pendingCallOutEvents.clear();

        } else {

            d->sendCallOutEvent(callOutEvent);

        }

        return true;

    }

    return QObject::event(event);

}

void QFutureWatcherBase::setPendingResultsLimit(int limit)

{

    Q_D(QFutureWatcherBase);

    d->maximumPendingResultsReady = limit;

}

void QFutureWatcherBase::connectNotify(const char * signal)

{

    Q_D(QFutureWatcherBase);

    if (qstrcmp(signal, SIGNAL(resultReadyAt(int))) == 0)

        d->resultAtConnected.ref();

}

void QFutureWatcherBase::disconnectNotify(const char * signal)

{

    Q_D(QFutureWatcherBase);

    if (qstrcmp(signal, SIGNAL(resultReadyAt(int))) == 0)

        d->resultAtConnected.deref();

}

/*!

    \internal

*/

QFutureWatcherBasePrivate::QFutureWatcherBasePrivate()

    : maximumPendingResultsReady(QThread::idealThreadCount() * 2),

      resultAtConnected(0)

{ }

/*!

    \internal

*/

void QFutureWatcherBase::connectOutputInterface()

{

    futureInterface().d->connectOutputInterface(d_func());

}

/*!

    \internal

*/

void QFutureWatcherBase::disconnectOutputInterface(bool pendingAssignment)

{

    if (pendingAssignment) {

        Q_D(QFutureWatcherBase);

        d->pendingResultsReady = 0;

        qDeleteAll(d->pendingCallOutEvents);

        d->pendingCallOutEvents.clear();

        d->finished = false;

    }

    futureInterface().d->disconnectOutputInterface(d_func());

}

void QFutureWatcherBasePrivate::postCallOutEvent(const QFutureCallOutEvent &callOutEvent)

{

    Q_Q(QFutureWatcherBase);

    if (callOutEvent.callOutType == QFutureCallOutEvent::ResultsReady) {

        if (pendingResultsReady.fetchAndAddRelaxed(1) >= maximumPendingResultsReady)

            q->futureInterface().d->internal_setThrottled(true);

    }

    QCoreApplication::postEvent(q, callOutEvent.clone());

}

void QFutureWatcherBasePrivate::callOutInterfaceDisconnected()

{

    QCoreApplication::removePostedEvents(q_func(), QEvent::FutureCallOut);

}

void QFutureWatcherBasePrivate::sendCallOutEvent(QFutureCallOutEvent *event)

{

    Q_Q(QFutureWatcherBase);

    switch (event->callOutType) {

        case QFutureCallOutEvent::Started:

            emit q->started();

        break;

        case QFutureCallOutEvent::Finished:

            finished = true;

            emit q->finished();

        break;

        case QFutureCallOutEvent::Canceled:

            pendingResultsReady = 0;

            emit q->canceled();

        break;

        case QFutureCallOutEvent::Paused:

            if (q->futureInterface().isCanceled())

                break;

            emit q->paused();

        break;

        case QFutureCallOutEvent::Resumed:

            if (q->futureInterface().isCanceled())

                break;

            emit q->resumed();

        break;

        case QFutureCallOutEvent::ResultsReady: {

            if (q->futureInterface().isCanceled())

                break;

            if (pendingResultsReady.fetchAndAddRelaxed(-1) <= maximumPendingResultsReady)

                q->futureInterface().setThrottled(false);

            const int beginIndex = event->index1;

            const int endIndex = event->index2;

            emit q->resultsReadyAt(beginIndex, endIndex);

            if (int(resultAtConnected) <= 0)

                break;

            for (int i = beginIndex; i < endIndex; ++i)

                emit q->resultReadyAt(i);

        } break;

        case QFutureCallOutEvent::Progress:

            if (q->futureInterface().isCanceled())

                break;

            emit q->progressValueChanged(event->index1);

            if (!event->text.isNull()) // ###

                q->progressTextChanged(event->text);

        break;

        case QFutureCallOutEvent::ProgressRange:

            emit q->progressRangeChanged(event->index1, event->index2);

        break;

        default: break;

    }

}

/*! \fn const T &QFutureWatcher::result() const

    Returns the first result in the future(). If the result is not immediately

    available, this function will block and wait for the result to become

    available. This is a convenience method for calling resultAt(0).

    \sa resultAt()

*/

/*! \fn const T &QFutureWatcher::resultAt(int index) const

    Returns the result at \a index in the future(). If the result is not

    immediately available, this function will block and wait for the result to

    become available.

    \sa result()

*/

/*! \fn void QFutureWatcher::setFuture(const QFuture<T> &future)

    Starts watching the given \a future.

*/

/*! \fn QFuture<T> QFutureWatcher::future() const

    Returns the watched future.

*/

/*! \fn void QFutureWatcher::started()

    This signal is emitted when this QFutureWatcher starts watching the future

    set with setFuture().

*/

/*!

    \fn void QFutureWatcher::finished()

    This signal is emitted when the watched future finishes.

*/

/*!

    \fn void QFutureWatcher::canceled()

    This signal is emitted if the watched future is canceled.

*/

/*! \fn void QFutureWatcher::paused()

    This signal is emitted when the watched future is paused.

*/