| /**************************************************************************** |
| ** |
| ** Copyright (C) 2016 The Qt Company Ltd. |
| ** Contact: https://www.qt.io/licensing/ |
| ** |
| ** This file is part of the QtConcurrent module of the Qt Toolkit. |
| ** |
| ** $QT_BEGIN_LICENSE:LGPL$ |
| ** Commercial License Usage |
| ** Licensees holding valid commercial Qt licenses may use this file in |
| ** accordance with the commercial license agreement provided with the |
| ** Software or, alternatively, in accordance with the terms contained in |
| ** a written agreement between you and The Qt Company. For licensing terms |
| ** and conditions see https://www.qt.io/terms-conditions. For further |
| ** information use the contact form at https://www.qt.io/contact-us. |
| ** |
| ** GNU Lesser General Public License Usage |
| ** Alternatively, this file may be used under the terms of the GNU Lesser |
| ** General Public License version 3 as published by the Free Software |
| ** Foundation and appearing in the file LICENSE.LGPL3 included in the |
| ** packaging of this file. Please review the following information to |
| ** ensure the GNU Lesser General Public License version 3 requirements |
| ** will be met: https://www.gnu.org/licenses/lgpl-3.0.html. |
| ** |
| ** GNU General Public License Usage |
| ** Alternatively, this file may be used under the terms of the GNU |
| ** General Public License version 2.0 or (at your option) the GNU General |
| ** Public license version 3 or any later version approved by the KDE Free |
| ** Qt Foundation. The licenses are as published by the Free Software |
| ** Foundation and appearing in the file LICENSE.GPL2 and LICENSE.GPL3 |
| ** included in the packaging of this file. Please review the following |
| ** information to ensure the GNU General Public License requirements will |
| ** be met: https://www.gnu.org/licenses/gpl-2.0.html and |
| ** https://www.gnu.org/licenses/gpl-3.0.html. |
| ** |
| ** $QT_END_LICENSE$ |
| ** |
| ****************************************************************************/ |
| |
| #include "qtconcurrentthreadengine.h" |
| |
| #if !defined(QT_NO_CONCURRENT) || defined(Q_CLANG_QDOC) |
| |
| QT_BEGIN_NAMESPACE |
| |
| namespace QtConcurrent { |
| |
| /*! |
| \class QtConcurrent::ThreadEngineBarrier |
| \inmodule QtConcurrent |
| \internal |
| */ |
| |
| /*! |
| \enum QtConcurrent::ThreadFunctionResult |
| \internal |
| */ |
| |
| /*! |
| \class QtConcurrent::ThreadEngineBase |
| \inmodule QtConcurrent |
| \internal |
| */ |
| |
| /*! |
| \class QtConcurrent::ThreadEngine |
| \inmodule QtConcurrent |
| \internal |
| */ |
| |
| /*! |
| \class QtConcurrent::ThreadEngineStarterBase |
| \inmodule QtConcurrent |
| \internal |
| */ |
| |
| /*! |
| \class QtConcurrent::ThreadEngineStarter |
| \inmodule QtConcurrent |
| \internal |
| */ |
| |
| /*! |
| \fn [qtconcurrentthreadengine-1] template <typename ThreadEngine> ThreadEngineStarter<typename ThreadEngine::ResultType> QtConcurrent::startThreadEngine(ThreadEngine *threadEngine) |
| \internal |
| */ |
| |
| ThreadEngineBarrier::ThreadEngineBarrier() |
| :count(0) { } |
| |
| void ThreadEngineBarrier::acquire() |
| { |
| forever { |
| int localCount = count.loadRelaxed(); |
| if (localCount < 0) { |
| if (count.testAndSetOrdered(localCount, localCount -1)) |
| return; |
| } else { |
| if (count.testAndSetOrdered(localCount, localCount + 1)) |
| return; |
| } |
| } |
| } |
| |
| int ThreadEngineBarrier::release() |
| { |
| forever { |
| int localCount = count.loadRelaxed(); |
| 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 = count.loadRelaxed(); |
| 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 count.loadRelaxed(); |
| } |
| |
| // releases a thread, unless this is the last thread. |
| // returns true if the thread was released. |
| bool ThreadEngineBarrier::releaseUnlessLast() |
| { |
| forever { |
| int localCount = count.loadRelaxed(); |
| 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 (QException &e) { |
| handleException(e); |
| } catch (...) { |
| handleException(QUnhandledException()); |
| } |
| #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 (QException &e) { |
| handleException(e); |
| } catch (...) { |
| handleException(QUnhandledException()); |
| } |
| #endif |
| threadExit(); |
| } |
| |
| #ifndef QT_NO_EXCEPTIONS |
| |
| void ThreadEngineBase::handleException(const QException &exception) |
| { |
| if (futureInterface) |
| futureInterface->reportException(exception); |
| else |
| exceptionStore.setException(exception); |
| } |
| #endif |
| |
| |
| } // namepsace QtConcurrent |
| |
| QT_END_NAMESPACE |
| |
| #endif // QT_NO_CONCURRENT |