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39
40#ifndef QTBASE_QTTASKBUILDER_H
41#define QTBASE_QTTASKBUILDER_H
42
43#if !defined(QT_NO_CONCURRENT) || defined(Q_CLANG_QDOC)
44
45#include <QtConcurrent/qtconcurrentstoredfunctioncall.h>
46
47QT_BEGIN_NAMESPACE
48
49#ifdef Q_CLANG_QDOC
50
51namespace QtConcurrent {
52
53enum class FutureResult { Ignore };
54
55using InvokeResultType = int;
56
57template <class Task, class ...Args>
58class QTaskBuilder
59{
60public:
61 [[nodiscard]]
62 QFuture<InvokeResultType> spawn();
63
64 void spawn(FutureResult);
65
66 template <class ...ExtraArgs>
67 [[nodiscard]]
68 QTaskBuilder<Task, ExtraArgs...> withArguments(ExtraArgs &&...args);
69
70 [[nodiscard]]
71 QTaskBuilder<Task, Args...> &onThreadPool(QThreadPool &newThreadPool);
72
73 [[nodiscard]]
74 QTaskBuilder<Task, Args...> &withPriority(int newPriority);
75};
76
77} // namespace QtConcurrent
78
79#else
80
81namespace QtConcurrent {
82
83enum class FutureResult { Ignore };
84
85template <class Task, class ...Args>
86class QTaskBuilder
87{
88public:
89 [[nodiscard]]
90 auto spawn()
91 {
92 return TaskResolver<std::decay_t<Task>, std::decay_t<Args>...>::run(
93 std::move(taskWithArgs), startParameters);
94 }
95
96 // We don't want to run with promise when we don't return a QFuture
97 void spawn(FutureResult)
98 {
99 (new StoredFunctionCall<Task, Args...>(std::move(taskWithArgs)))
100 ->start(startParameters);
101 }
102
103 template <class ...ExtraArgs>
104 [[nodiscard]]
105 constexpr auto withArguments(ExtraArgs &&...args)
106 {
107 static_assert(std::tuple_size_v<TaskWithArgs> == 1,
108 "This function cannot be invoked if "
109 "arguments have already been passed.");
110
111 static_assert(sizeof...(ExtraArgs) >= 1,
112 "One or more arguments must be passed.");
113
114 // We have to re-create a builder, because the type has changed
115 return QTaskBuilder<Task, ExtraArgs...>(
116 startParameters,
117 std::get<0>(std::move(taskWithArgs)),
118 std::forward<ExtraArgs>(args)...
119 );
120 }
121
122 [[nodiscard]]
123 constexpr auto &onThreadPool(QThreadPool &newThreadPool)
124 {
125 startParameters.threadPool = &newThreadPool;
126 return *this;
127 }
128
129 [[nodiscard]]
130 constexpr auto &withPriority(int newPriority)
131 {
132 startParameters.priority = newPriority;
133 return *this;
134 }
135
136protected: // Methods
137 constexpr explicit QTaskBuilder(Task &&task, Args &&...arguments)
138 : taskWithArgs{std::forward<Task>(task), std::forward<Args>(arguments)...}
139 {}
140
141 constexpr QTaskBuilder(
142 const TaskStartParameters &parameters, Task &&task, Args &&...arguments)
143 : taskWithArgs{std::forward<Task>(task), std::forward<Args>(arguments)...}
144 , startParameters{parameters}
145 {}
146
147private: // Methods
148 // Required for creating a builder from "task" function
149 template <class T>
150 friend constexpr auto task(T &&t);
151
152 // Required for creating a new builder from "withArguments" function
153 template <class T, class ...A>
154 friend class QTaskBuilder;
155
156private: // Data
157 using TaskWithArgs = DecayedTuple<Task, Args...>;
158
159 TaskWithArgs taskWithArgs;
160 TaskStartParameters startParameters;
161};
162
163} // namespace QtConcurrent
164
165#endif // Q_CLANG_QDOC
166
167QT_END_NAMESPACE
168
169#endif // !defined(QT_NO_CONCURRENT)
170
171#endif //QTBASE_QTTASKBUILDER_H
172