diff options
author | Corentin Jabot <corentinjabot@gmail.com> | 2013-01-20 13:24:30 +0100 |
---|---|---|
committer | The Qt Project <gerrit-noreply@qt-project.org> | 2013-09-05 08:20:18 +0200 |
commit | 5a02d30a78991240c3355d863f52b0d376ebf911 (patch) | |
tree | ad02a7281b44f452016bae6a31ec3a25f8905596 /src/corelib/thread/qthread.cpp | |
parent | 34195aa6cbc3bbe2b0bb38a86a3fb3ad76c40499 (diff) |
Add an advisory interruption mechanism to QThread.
To ease interruption of long running tasks, a new method
QThread::setInterruptionRequested() can be called.
The task can check QThread::isInterruptionRequested()
and act upon it by stopping itself.
These methods are designed to replace the use of a global variable
and other hacky ways to stop a task running in another thread.
Change-Id: I17622dd60d2262078210e7e4294ad6c53a6dc179
Reviewed-by: Oswald Buddenhagen <oswald.buddenhagen@digia.com>
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>
Diffstat (limited to 'src/corelib/thread/qthread.cpp')
-rw-r--r-- | src/corelib/thread/qthread.cpp | 60 |
1 files changed, 59 insertions, 1 deletions
diff --git a/src/corelib/thread/qthread.cpp b/src/corelib/thread/qthread.cpp index 4d5bee3154..35d57b3d83 100644 --- a/src/corelib/thread/qthread.cpp +++ b/src/corelib/thread/qthread.cpp @@ -146,7 +146,8 @@ void QAdoptedThread::run() QThreadPrivate::QThreadPrivate(QThreadData *d) : QObjectPrivate(), running(false), finished(false), - isInFinish(false), exited(false), returnCode(-1), + isInFinish(false), interruptionRequested(false), + exited(false), returnCode(-1), stackSize(0), priority(QThread::InheritPriority), data(d) { #if defined (Q_OS_UNIX) @@ -801,4 +802,61 @@ bool QThread::event(QEvent *event) } } +/*! + \since 5.2 + + Request the interruption of the thread. + That request is advisory and it is up to code running on the thread to decide + if and how it should act upon such request. + This function does not stop any event loop running on the thread and + does not terminate it in any way. + + \sa isInterruptionRequested() +*/ + +void QThread::requestInterruption() +{ + Q_D(QThread); + QMutexLocker locker(&d->mutex); + if (!d->running || d->finished || d->isInFinish) + return; + if (this == QCoreApplicationPrivate::theMainThread) { + qWarning("QThread::requestInterruption has no effect on the main thread"); + return; + } + d->interruptionRequested = true; +} + +/*! + \since 5.2 + + Return true if the task running on this thread should be stopped. + An interruption can be requested by requestInterruption(). + + This function can be used to make long running tasks cleanly interruptible. + Never checking or acting on the value returned by this function is safe, + however it is advisable do so regularly in long running functions. + Take care not to call it too often, to keep the overhead low. + + \code + void long_task() { + forever { + if ( QThread::currentThread()->isInterruptionRequested() ) { + return; + } + } + } + \endcode + + \sa currentThread() requestInterruption() +*/ +bool QThread::isInterruptionRequested() const +{ + Q_D(const QThread); + QMutexLocker locker(&d->mutex); + if (!d->running || d->finished || d->isInFinish) + return false; + return d->interruptionRequested; +} + QT_END_NAMESPACE |