qt6-bb10/src/concurrent/qtaskbuilder.h

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3.4 KiB
C++

// Copyright (C) 2020 The Qt Company Ltd.
// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR LGPL-3.0-only OR GPL-2.0-only OR GPL-3.0-only
#ifndef QTBASE_QTTASKBUILDER_H
#define QTBASE_QTTASKBUILDER_H
#if !defined(QT_NO_CONCURRENT) || defined(Q_QDOC)
#include <QtConcurrent/qtconcurrentstoredfunctioncall.h>
QT_BEGIN_NAMESPACE
#ifdef Q_QDOC
namespace QtConcurrent {
enum class FutureResult { Ignore };
using InvokeResultType = int;
template <class Task, class ...Args>
class QTaskBuilder
{
public:
[[nodiscard]]
QFuture<InvokeResultType> spawn();
void spawn(FutureResult);
template <class ...ExtraArgs>
[[nodiscard]]
QTaskBuilder<Task, ExtraArgs...> withArguments(ExtraArgs &&...args);
[[nodiscard]]
QTaskBuilder<Task, Args...> &onThreadPool(QThreadPool &newThreadPool);
[[nodiscard]]
QTaskBuilder<Task, Args...> &withPriority(int newPriority);
};
} // namespace QtConcurrent
#else
namespace QtConcurrent {
enum class FutureResult { Ignore };
template <class Task, class ...Args>
class QTaskBuilder
{
public:
[[nodiscard]]
auto spawn()
{
return TaskResolver<std::decay_t<Task>, std::decay_t<Args>...>::run(
std::move(taskWithArgs), startParameters);
}
// We don't want to run with promise when we don't return a QFuture
void spawn(FutureResult)
{
(new StoredFunctionCall<Task, Args...>(std::move(taskWithArgs)))
->start(startParameters);
}
template <class ...ExtraArgs>
[[nodiscard]]
constexpr auto withArguments(ExtraArgs &&...args)
{
static_assert(std::tuple_size_v<TaskWithArgs> == 1,
"This function cannot be invoked if "
"arguments have already been passed.");
static_assert(sizeof...(ExtraArgs) >= 1,
"One or more arguments must be passed.");
// We have to re-create a builder, because the type has changed
return QTaskBuilder<Task, ExtraArgs...>(
startParameters,
std::get<0>(std::move(taskWithArgs)),
std::forward<ExtraArgs>(args)...
);
}
[[nodiscard]]
constexpr auto &onThreadPool(QThreadPool &newThreadPool)
{
startParameters.threadPool = &newThreadPool;
return *this;
}
[[nodiscard]]
constexpr auto &withPriority(int newPriority)
{
startParameters.priority = newPriority;
return *this;
}
protected: // Methods
constexpr explicit QTaskBuilder(Task &&task, Args &&...arguments)
: taskWithArgs{std::forward<Task>(task), std::forward<Args>(arguments)...}
{}
constexpr QTaskBuilder(
const TaskStartParameters &parameters, Task &&task, Args &&...arguments)
: taskWithArgs{std::forward<Task>(task), std::forward<Args>(arguments)...}
, startParameters{parameters}
{}
private: // Methods
// Required for creating a builder from "task" function
template <class T>
friend constexpr auto task(T &&t);
// Required for creating a new builder from "withArguments" function
template <class T, class ...A>
friend class QTaskBuilder;
private: // Data
using TaskWithArgs = DecayedTuple<Task, Args...>;
TaskWithArgs taskWithArgs;
TaskStartParameters startParameters;
};
} // namespace QtConcurrent
#endif // Q_QDOC
QT_END_NAMESPACE
#endif // !defined(QT_NO_CONCURRENT)
#endif //QTBASE_QTTASKBUILDER_H