1/****************************************************************************
2**
3** Copyright (C) 2016 The Qt Company Ltd.
4** Contact: https://www.qt.io/licensing/
5**
6** This file is part of the QtConcurrent module of the Qt Toolkit.
7**
8** $QT_BEGIN_LICENSE:LGPL$
9** Commercial License Usage
10** Licensees holding valid commercial Qt licenses may use this file in
11** accordance with the commercial license agreement provided with the
12** Software or, alternatively, in accordance with the terms contained in
13** a written agreement between you and The Qt Company. For licensing terms
14** and conditions see https://www.qt.io/terms-conditions. For further
15** information use the contact form at https://www.qt.io/contact-us.
16**
17** GNU Lesser General Public License Usage
18** Alternatively, this file may be used under the terms of the GNU Lesser
19** General Public License version 3 as published by the Free Software
20** Foundation and appearing in the file LICENSE.LGPL3 included in the
21** packaging of this file. Please review the following information to
22** ensure the GNU Lesser General Public License version 3 requirements
23** will be met: https://www.gnu.org/licenses/lgpl-3.0.html.
24**
25** GNU General Public License Usage
26** Alternatively, this file may be used under the terms of the GNU
27** General Public License version 2.0 or (at your option) the GNU General
28** Public license version 3 or any later version approved by the KDE Free
29** Qt Foundation. The licenses are as published by the Free Software
30** Foundation and appearing in the file LICENSE.GPL2 and LICENSE.GPL3
31** included in the packaging of this file. Please review the following
32** information to ensure the GNU General Public License requirements will
33** be met: https://www.gnu.org/licenses/gpl-2.0.html and
34** https://www.gnu.org/licenses/gpl-3.0.html.
35**
36** $QT_END_LICENSE$
37**
38****************************************************************************/
39
40#ifndef QTCONCURRENT_RUNBASE_H
41#define QTCONCURRENT_RUNBASE_H
42
43#include <QtConcurrent/qtconcurrent_global.h>
44
45#ifndef QT_NO_CONCURRENT
46
47#include <QtCore/qfuture.h>
48#include <QtCore/qrunnable.h>
49#include <QtCore/qthreadpool.h>
50
51#include <type_traits>
52#include <utility>
53
54QT_BEGIN_NAMESPACE
55
56
57#ifndef Q_QDOC
58
59namespace QtConcurrent {
60
61template <typename T>
62struct SelectSpecialization
63{
64 template <class Normal, class Void>
65 struct Type { typedef Normal type; };
66};
67
68template <>
69struct SelectSpecialization<void>
70{
71 template <class Normal, class Void>
72 struct Type { typedef Void type; };
73};
74
75struct TaskStartParameters
76{
77 QThreadPool *threadPool = QThreadPool::globalInstance();
78 int priority = 0;
79};
80
81template <typename T>
82class RunFunctionTaskBase : public QRunnable
83{
84public:
85 QFuture<T> start()
86 {
87 return start(TaskStartParameters());
88 }
89
90 QFuture<T> start(const TaskStartParameters &parameters)
91 {
92 promise.setThreadPool(parameters.threadPool);
93 promise.setRunnable(this);
94 promise.reportStarted();
95 QFuture<T> theFuture = promise.future();
96 parameters.threadPool->start(this, parameters.priority);
97 return theFuture;
98 }
99
100 // For backward compatibility
101 QFuture<T> start(QThreadPool *pool) { return start({pool, 0}); }
102
103 void run() override
104 {
105 if (promise.isCanceled()) {
106 promise.reportFinished();
107 return;
108 }
109#ifndef QT_NO_EXCEPTIONS
110 try {
111#endif
112 runFunctor();
113#ifndef QT_NO_EXCEPTIONS
114 } catch (QException &e) {
115 promise.reportException(e);
116 } catch (...) {
117 promise.reportException(QUnhandledException(std::current_exception()));
118 }
119#endif
120
121 reportResult();
122
123 promise.reportFinished();
124 }
125
126protected:
127 virtual void runFunctor() = 0;
128 virtual void reportResult() {}
129
130 QFutureInterface<T> promise;
131};
132
133template <typename T>
134class RunFunctionTask : public RunFunctionTaskBase<T>
135{
136protected:
137 void reportResult() override
138 {
139 if constexpr (std::is_move_constructible_v<T>)
140 this->promise.reportAndMoveResult(std::move(result));
141 else if constexpr (std::is_copy_constructible_v<T>)
142 this->promise.reportResult(result);
143 }
144
145 T result;
146};
147
148template <>
149class RunFunctionTask<void> : public RunFunctionTaskBase<void> {};
150
151} //namespace QtConcurrent
152
153#endif //Q_QDOC
154
155QT_END_NAMESPACE
156
157#endif // QT_NO_CONCURRENT
158
159#endif
160