include/QtConcurrent/qtconcurrentrunbase.h

0001 // Copyright (C) 2016 The Qt Company Ltd.
0002 // SPDX-License-Identifier: LicenseRef-Qt-Commercial OR LGPL-3.0-only OR GPL-2.0-only OR GPL-3.0-only
0003 // Qt-Security score:significant reason:default
0004
0005 #ifndef QTCONCURRENT_RUNBASE_H
0006 #define QTCONCURRENT_RUNBASE_H
0007
0008 #include <QtConcurrent/qtconcurrent_global.h>
0009
0010 #ifndef QT_NO_CONCURRENT
0011
0012 #include <QtCore/qfuture.h>
0013 #include <QtCore/qrunnable.h>
0014 #include <QtCore/qthreadpool.h>
0015
0016 #include <type_traits>
0017 #include <utility>
0018
0019 QT_BEGIN_NAMESPACE
0020
0021
0022 #ifndef Q_QDOC
0023
0024 namespace QtConcurrent {
0025
0026 template <typename T>
0027 struct SelectSpecialization
0028 {
0029     template <class Normal, class Void>
0030     struct Type { typedef Normal type; };
0031 };
0032
0033 template <>
0034 struct SelectSpecialization<void>
0035 {
0036     template <class Normal, class Void>
0037     struct Type { typedef Void type; };
0038 };
0039
0040 struct TaskStartParameters
0041 {
0042     QThreadPool *threadPool = QThreadPool::globalInstance();
0043     int priority = 0;
0044 };
0045
0046 template <typename T>
0047 class RunFunctionTaskBase : public QRunnable
0048 {
0049 public:
0050     QFuture<T> start()
0051     {
0052         return start(TaskStartParameters());
0053     }
0054
0055     QFuture<T> start(const TaskStartParameters &parameters)
0056     {
0057         promise.setThreadPool(parameters.threadPool);
0058         promise.setRunnable(this);
0059         promise.reportStarted();
0060         QFuture<T> theFuture = promise.future();
0061
0062         if (parameters.threadPool) {
0063             parameters.threadPool->start(this, parameters.priority);
0064         } else {
0065             promise.reportCanceled();
0066             promise.reportFinished();
0067             delete this;
0068         }
0069         return theFuture;
0070     }
0071
0072     // For backward compatibility
0073     QFuture<T> start(QThreadPool *pool) { return start({pool, 0});  }
0074
0075     void run() override
0076     {
0077         if (promise.isCanceled()) {
0078             promise.reportFinished();
0079             return;
0080         }
0081 #ifndef QT_NO_EXCEPTIONS
0082         try {
0083 #endif
0084             runFunctor();
0085 #ifndef QT_NO_EXCEPTIONS
0086         } catch (QException &e) {
0087             promise.reportException(e);
0088         } catch (...) {
0089             promise.reportException(QUnhandledException(std::current_exception()));
0090         }
0091 #endif
0092         promise.reportFinished();
0093     }
0094
0095 protected:
0096     virtual void runFunctor() = 0;
0097
0098     QFutureInterface<T> promise;
0099 };
0100
0101 } //namespace QtConcurrent
0102
0103 #endif //Q_QDOC
0104
0105 QT_END_NAMESPACE
0106
0107 #endif // QT_NO_CONCURRENT
0108
0109 #endif