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Diffstat (limited to 'src/corelib/concurrent/qtconcurrentthreadengine.cpp')
-rw-r--r-- | src/corelib/concurrent/qtconcurrentthreadengine.cpp | 299 |
1 files changed, 299 insertions, 0 deletions
diff --git a/src/corelib/concurrent/qtconcurrentthreadengine.cpp b/src/corelib/concurrent/qtconcurrentthreadengine.cpp new file mode 100644 index 0000000000..db6217b83a --- /dev/null +++ b/src/corelib/concurrent/qtconcurrentthreadengine.cpp @@ -0,0 +1,299 @@ +/**************************************************************************** +** +** Copyright (C) 2011 Nokia Corporation and/or its subsidiary(-ies). +** All rights reserved. +** Contact: Nokia Corporation (qt-info@nokia.com) +** +** This file is part of the QtCore module of the Qt Toolkit. +** +** $QT_BEGIN_LICENSE:LGPL$ +** No Commercial Usage +** This file contains pre-release code and may not be distributed. +** You may use this file in accordance with the terms and conditions +** contained in the Technology Preview License Agreement accompanying +** this package. +** +** GNU Lesser General Public License Usage +** Alternatively, this file may be used under the terms of the GNU Lesser +** General Public License version 2.1 as published by the Free Software +** Foundation and appearing in the file LICENSE.LGPL included in the +** packaging of this file. Please review the following information to +** ensure the GNU Lesser General Public License version 2.1 requirements +** will be met: http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html. +** +** In addition, as a special exception, Nokia gives you certain additional +** rights. These rights are described in the Nokia Qt LGPL Exception +** version 1.1, included in the file LGPL_EXCEPTION.txt in this package. +** +** If you have questions regarding the use of this file, please contact +** Nokia at qt-info@nokia.com. +** +** +** +** +** +** +** +** +** $QT_END_LICENSE$ +** +****************************************************************************/ + +#include "qtconcurrentthreadengine.h" + +#ifndef QT_NO_CONCURRENT + +QT_BEGIN_NAMESPACE + +namespace QtConcurrent { + +ThreadEngineBarrier::ThreadEngineBarrier() +:count(0) { } + +void ThreadEngineBarrier::acquire() +{ + forever { + int localCount = int(count); + if (localCount < 0) { + if (count.testAndSetOrdered(localCount, localCount -1)) + return; + } else { + if (count.testAndSetOrdered(localCount, localCount + 1)) + return; + } + } +} + +int ThreadEngineBarrier::release() +{ + forever { + int localCount = int(count); + if (localCount == -1) { + if (count.testAndSetOrdered(-1, 0)) { + semaphore.release(); + return 0; + } + } else if (localCount < 0) { + if (count.testAndSetOrdered(localCount, localCount + 1)) + return qAbs(localCount + 1); + } else { + if (count.testAndSetOrdered(localCount, localCount - 1)) + return localCount - 1; + } + } +} + +// Wait until all threads have been released +void ThreadEngineBarrier::wait() +{ + forever { + int localCount = int(count); + if (localCount == 0) + return; + + Q_ASSERT(localCount > 0); // multiple waiters are not allowed. + if (count.testAndSetOrdered(localCount, -localCount)) { + semaphore.acquire(); + return; + } + } +} + +int ThreadEngineBarrier::currentCount() +{ + return int(count); +} + +// releases a thread, unless this is the last thread. +// returns true if the thread was released. +bool ThreadEngineBarrier::releaseUnlessLast() +{ + forever { + int localCount = int(count); + if (qAbs(localCount) == 1) { + return false; + } else if (localCount < 0) { + if (count.testAndSetOrdered(localCount, localCount + 1)) + return true; + } else { + if (count.testAndSetOrdered(localCount, localCount - 1)) + return true; + } + } +} + +ThreadEngineBase::ThreadEngineBase() +:futureInterface(0), threadPool(QThreadPool::globalInstance()) +{ + setAutoDelete(false); +} + +ThreadEngineBase::~ThreadEngineBase() {} + +void ThreadEngineBase::startSingleThreaded() +{ + start(); + while (threadFunction() != ThreadFinished) + ; + finish(); +} + +void ThreadEngineBase::startBlocking() +{ + start(); + barrier.acquire(); + startThreads(); + + bool throttled = false; +#ifndef QT_NO_EXCEPTIONS + try { +#endif + while (threadFunction() == ThrottleThread) { + if (threadThrottleExit()) { + throttled = true; + break; + } + } +#ifndef QT_NO_EXCEPTIONS + } catch (QtConcurrent::Exception &e) { + handleException(e); + } catch (...) { + handleException(QtConcurrent::UnhandledException()); + } +#endif + + if (throttled == false) { + barrier.release(); + } + + barrier.wait(); + finish(); + exceptionStore.throwPossibleException(); +} + +void ThreadEngineBase::startThread() +{ + startThreadInternal(); +} + +void ThreadEngineBase::acquireBarrierSemaphore() +{ + barrier.acquire(); +} + +bool ThreadEngineBase::isCanceled() +{ + if (futureInterface) + return futureInterface->isCanceled(); + else + return false; +} + +void ThreadEngineBase::waitForResume() +{ + if (futureInterface) + futureInterface->waitForResume(); +} + +bool ThreadEngineBase::isProgressReportingEnabled() +{ + // If we don't have a QFuture, there is no-one to report the progress to. + return (futureInterface != 0); +} + +void ThreadEngineBase::setProgressValue(int progress) +{ + if (futureInterface) + futureInterface->setProgressValue(progress); +} + +void ThreadEngineBase::setProgressRange(int minimum, int maximum) +{ + if (futureInterface) + futureInterface->setProgressRange(minimum, maximum); +} + +bool ThreadEngineBase::startThreadInternal() +{ + if (this->isCanceled()) + return false; + + barrier.acquire(); + if (!threadPool->tryStart(this)) { + barrier.release(); + return false; + } + return true; +} + +void ThreadEngineBase::startThreads() +{ + while (shouldStartThread() && startThreadInternal()) + ; +} + +void ThreadEngineBase::threadExit() +{ + const bool asynchronous = futureInterface != 0; + const int lastThread = (barrier.release() == 0); + + if (lastThread && asynchronous) + this->asynchronousFinish(); +} + +// Called by a worker thread that wants to be throttled. If the current number +// of running threads is larger than one the thread is allowed to exit and +// this function returns one. +bool ThreadEngineBase::threadThrottleExit() +{ + return barrier.releaseUnlessLast(); +} + +void ThreadEngineBase::run() // implements QRunnable. +{ + if (this->isCanceled()) { + threadExit(); + return; + } + + startThreads(); + +#ifndef QT_NO_EXCEPTIONS + try { +#endif + while (threadFunction() == ThrottleThread) { + // threadFunction returning ThrottleThread means it that the user + // struct wants to be throttled by making a worker thread exit. + // Respect that request unless this is the only worker thread left + // running, in which case it has to keep going. + if (threadThrottleExit()) + return; + } + +#ifndef QT_NO_EXCEPTIONS + } catch (QtConcurrent::Exception &e) { + handleException(e); + } catch (...) { + handleException(QtConcurrent::UnhandledException()); + } +#endif + threadExit(); +} + +#ifndef QT_NO_EXCEPTIONS + +void ThreadEngineBase::handleException(const QtConcurrent::Exception &exception) +{ + if (futureInterface) + futureInterface->reportException(exception); + else + exceptionStore.setException(exception); +} +#endif + + +} // namepsace QtConcurrent + +QT_END_NAMESPACE + +#endif // QT_NO_CONCURRENT |