source: trunk/src/corelib/concurrent/qfuturewatcher.cpp@ 769

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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
{