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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 (new StoredFunctionCall<Task, Args...>(std::move(taskWithArgs)))
93 ->start(startParameters);
94 }
95
96 void spawn(FutureResult)
97 {
98 (new StoredFunctionCall<Task, Args...>(std::move(taskWithArgs)))
99 ->start(startParameters);
100 }
101
102 template <class ...ExtraArgs>
103 [[nodiscard]]
104 constexpr auto withArguments(ExtraArgs &&...args)
105 {
106 static_assert(std::tuple_size_v<TaskWithArgs> == 1,
107 "This function cannot be invoked if "
108 "arguments have already been passed.");
109
110 static_assert(sizeof...(ExtraArgs) >= 1,
111 "One or more arguments must be passed.");
112
113 // We have to re-create a builder, because the type has changed
114 return QTaskBuilder<Task, ExtraArgs...>(
115 startParameters,
116 std::get<0>(std::move(taskWithArgs)),
117 std::forward<ExtraArgs>(args)...
118 );
119 }
120
121 [[nodiscard]]
122 constexpr auto &onThreadPool(QThreadPool &newThreadPool)
123 {
124 startParameters.threadPool = &newThreadPool;
125 return *this;
126 }
127
128 [[nodiscard]]
129 constexpr auto &withPriority(int newPriority)
130 {
131 startParameters.priority = newPriority;
132 return *this;
133 }
134
135protected: // Methods
136 constexpr explicit QTaskBuilder(Task &&task, Args &&...arguments)
137 : taskWithArgs{std::forward<Task>(task), std::forward<Args>(arguments)...}
138 {}
139
140 constexpr QTaskBuilder(
141 const TaskStartParameters &parameters, Task &&task, Args &&...arguments)
142 : taskWithArgs{std::forward<Task>(task), std::forward<Args>(arguments)...}
143 , startParameters{parameters}
144 {}
145
146private: // Methods
147 // Required for creating a builder from "task" function
148 template <class T>
149 friend constexpr auto task(T &&t);
150
151 // Required for creating a new builder from "withArguments" function
152 template <class T, class ...A>
153 friend class QTaskBuilder;
154
155private: // Data
156 using TaskWithArgs = DecayedTuple<Task, Args...>;
157
158 TaskWithArgs taskWithArgs;
159 TaskStartParameters startParameters;
160};
161
162} // namespace QtConcurrent
163
164#endif // Q_CLANG_QDOC
165
166QT_END_NAMESPACE
167
168#endif // !defined(QT_NO_CONCURRENT)
169
170#endif //QTBASE_QTTASKBUILDER_H
171