438 lines
16 KiB
C++
438 lines
16 KiB
C++
/****************************************************************************
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**
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** Copyright (C) 2016 The Qt Company Ltd.
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** Contact: https://www.qt.io/licensing/
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**
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** This file is part of the QtCore module of the Qt Toolkit.
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**
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** $QT_BEGIN_LICENSE:LGPL$
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** Commercial License Usage
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** Licensees holding valid commercial Qt licenses may use this file in
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** accordance with the commercial license agreement provided with the
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** Software or, alternatively, in accordance with the terms contained in
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** a written agreement between you and The Qt Company. For licensing terms
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** and conditions see https://www.qt.io/terms-conditions. For further
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** information use the contact form at https://www.qt.io/contact-us.
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**
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** GNU Lesser General Public License Usage
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** Alternatively, this file may be used under the terms of the GNU Lesser
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** General Public License version 3 as published by the Free Software
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** Foundation and appearing in the file LICENSE.LGPL3 included in the
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** packaging of this file. Please review the following information to
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** ensure the GNU Lesser General Public License version 3 requirements
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** will be met: https://www.gnu.org/licenses/lgpl-3.0.html.
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**
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** GNU General Public License Usage
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** Alternatively, this file may be used under the terms of the GNU
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** General Public License version 2.0 or (at your option) the GNU General
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** Public license version 3 or any later version approved by the KDE Free
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** Qt Foundation. The licenses are as published by the Free Software
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** Foundation and appearing in the file LICENSE.GPL2 and LICENSE.GPL3
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** included in the packaging of this file. Please review the following
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** information to ensure the GNU General Public License requirements will
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** be met: https://www.gnu.org/licenses/gpl-2.0.html and
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** https://www.gnu.org/licenses/gpl-3.0.html.
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**
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** $QT_END_LICENSE$
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**
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****************************************************************************/
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#ifndef QFUTURE_H
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#define QFUTURE_H
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#include <QtCore/qglobal.h>
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#include <QtCore/qfutureinterface.h>
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#include <QtCore/qstring.h>
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#include <QtCore/qfuture_impl.h>
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#include <type_traits>
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QT_REQUIRE_CONFIG(future);
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QT_BEGIN_NAMESPACE
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template <typename T>
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class QFutureWatcher;
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template <typename T>
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class QFuture
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{
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static_assert (std::is_move_constructible_v<T>
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|| std::is_same_v<T, void>,
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"A move-constructible type or type void is required");
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public:
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QFuture()
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: d(QFutureInterface<T>::canceledResult())
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{ }
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template<typename U = T, typename = QtPrivate::EnableForNonVoid<U>>
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explicit QFuture(QFutureInterface<T> *p) // internal
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: d(*p)
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{ }
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template<typename U = T, typename = QtPrivate::EnableForVoid<U>>
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explicit QFuture(QFutureInterfaceBase *p) // internal
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: d(*p)
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{
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}
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template<typename U, typename V = T, typename = QtPrivate::EnableForVoid<V>>
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explicit QFuture(const QFuture<U> &other) : d(other.d)
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{
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}
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template<typename U, typename V = T, typename = QtPrivate::EnableForVoid<V>>
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QFuture<void> &operator=(const QFuture<U> &other)
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{
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d = other.d;
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return *this;
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}
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#if defined(Q_CLANG_QDOC)
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~QFuture() { }
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QFuture(const QFuture<T> &) { }
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QFuture<T> & operator=(const QFuture<T> &) { }
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#endif
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void cancel() { d.cancel(); }
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bool isCanceled() const { return d.isCanceled(); }
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#if QT_DEPRECATED_SINCE(6, 0)
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QT_DEPRECATED_VERSION_X_6_0("Use setSuspended() instead.")
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void setPaused(bool paused) { d.setSuspended(paused); }
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QT_DEPRECATED_VERSION_X_6_0("Use isSuspending() or isSuspended() instead.")
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bool isPaused() const
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{
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QT_WARNING_PUSH
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QT_WARNING_DISABLE_DEPRECATED
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return d.isPaused();
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QT_WARNING_POP
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}
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QT_DEPRECATED_VERSION_X_6_0("Use toggleSuspended() instead.")
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void togglePaused() { d.toggleSuspended(); }
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QT_DEPRECATED_VERSION_X_6_0("Use suspend() instead.")
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void pause() { suspend(); }
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#endif
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bool isSuspending() const { return d.isSuspending(); }
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bool isSuspended() const { return d.isSuspended(); }
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void setSuspended(bool suspend) { d.setSuspended(suspend); }
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void suspend() { setSuspended(true); }
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void resume() { setSuspended(false); }
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void toggleSuspended() { d.toggleSuspended(); }
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bool isStarted() const { return d.isStarted(); }
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bool isFinished() const { return d.isFinished(); }
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bool isRunning() const { return d.isRunning(); }
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int resultCount() const { return d.resultCount(); }
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int progressValue() const { return d.progressValue(); }
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int progressMinimum() const { return d.progressMinimum(); }
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int progressMaximum() const { return d.progressMaximum(); }
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QString progressText() const { return d.progressText(); }
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void waitForFinished() { d.waitForFinished(); }
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template<typename U = T, typename = QtPrivate::EnableForNonVoid<U>>
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inline T result() const;
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template<typename U = T, typename = QtPrivate::EnableForNonVoid<U>>
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inline T resultAt(int index) const;
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template<typename U = T, typename = QtPrivate::EnableForNonVoid<U>>
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bool isResultReadyAt(int resultIndex) const { return d.isResultReadyAt(resultIndex); }
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template<typename U = T, typename = QtPrivate::EnableForNonVoid<U>>
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QList<T> results() const { return d.results(); }
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template<typename U = T, typename = QtPrivate::EnableForNonVoid<U>>
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T takeResult() { return d.takeResult(); }
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#if 0
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// TODO: Enable and make it return a QList, when QList is fixed to support move-only types
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template<typename U = T, typename = QtPrivate::EnableForNonVoid<U>>
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std::vector<T> takeResults() { return d.takeResults(); }
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#endif
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bool isValid() const { return d.isValid(); }
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template<class Function>
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using ResultType = typename QtPrivate::ResultTypeHelper<Function, T>::ResultType;
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template<class Function>
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QFuture<ResultType<Function>> then(Function &&function);
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template<class Function>
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QFuture<ResultType<Function>> then(QtFuture::Launch policy, Function &&function);
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template<class Function>
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QFuture<ResultType<Function>> then(QThreadPool *pool, Function &&function);
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template<class Function>
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QFuture<ResultType<Function>> then(QObject *context, Function &&function);
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#ifndef QT_NO_EXCEPTIONS
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template<class Function,
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typename = std::enable_if_t<!QtPrivate::ArgResolver<Function>::HasExtraArgs>>
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QFuture<T> onFailed(Function &&handler);
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template<class Function,
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typename = std::enable_if_t<!QtPrivate::ArgResolver<Function>::HasExtraArgs>>
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QFuture<T> onFailed(QObject *context, Function &&handler);
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#endif
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template<class Function, typename = std::enable_if_t<std::is_invocable_r_v<T, Function>>>
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QFuture<T> onCanceled(Function &&handler);
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template<class Function, typename = std::enable_if_t<std::is_invocable_r_v<T, Function>>>
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QFuture<T> onCanceled(QObject *context, Function &&handler);
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class const_iterator
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{
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public:
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static_assert(!std::is_same_v<T, void>,
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"It isn't possible to define QFuture<void>::const_iterator");
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typedef std::bidirectional_iterator_tag iterator_category;
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typedef qptrdiff difference_type;
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typedef T value_type;
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typedef const T *pointer;
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typedef const T &reference;
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inline const_iterator() {}
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inline const_iterator(QFuture const * const _future, int _index)
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: future(_future), index(advanceIndex(_index, 0)) { }
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inline const_iterator(const const_iterator &o) : future(o.future), index(o.index) {}
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inline const_iterator &operator=(const const_iterator &o)
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{ future = o.future; index = o.index; return *this; }
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inline const T &operator*() const { return future->d.resultReference(index); }
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inline const T *operator->() const { return future->d.resultPointer(index); }
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inline bool operator!=(const const_iterator &other) const { return index != other.index; }
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inline bool operator==(const const_iterator &o) const { return !operator!=(o); }
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inline const_iterator &operator++()
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{ index = advanceIndex(index, 1); return *this; }
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inline const_iterator &operator--()
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{ index = advanceIndex(index, -1); return *this; }
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inline const_iterator operator++(int)
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{
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const_iterator r = *this;
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index = advanceIndex(index, 1);
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return r;
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}
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inline const_iterator operator--(int)
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{
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const_iterator r = *this;
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index = advanceIndex(index, -1);
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return r;
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}
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inline const_iterator operator+(int j) const
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{ return const_iterator(future, advanceIndex(index, j)); }
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inline const_iterator operator-(int j) const
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{ return const_iterator(future, advanceIndex(index, -j)); }
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inline const_iterator &operator+=(int j)
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{ index = advanceIndex(index, j); return *this; }
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inline const_iterator &operator-=(int j)
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{ index = advanceIndex(index, -j); return *this; }
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friend inline const_iterator operator+(int j, const_iterator k)
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{ return const_iterator(k.future, k.advanceIndex(k.index, j)); }
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private:
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/*! \internal
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Advances the iterator index \a idx \a n steps, waits for the
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result at the target index, and returns the target index.
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The index may be -1, indicating the end iterator, either
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as the argument or as the return value. The end iterator
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may be decremented.
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The caller is responsible for not advancing the iterator
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before begin() or past end(), with the exception that
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attempting to advance a non-end iterator past end() for
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a running future is allowed and will return the end iterator.
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Note that n == 0 is valid and will wait for the result
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at the given index.
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*/
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int advanceIndex(int idx, int n) const
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{
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// The end iterator can be decremented, leave as-is for other cases
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if (idx == -1 && n >= 0)
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return idx;
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// Special case for decrementing the end iterator: wait for
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// finished to get the total result count.
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if (idx == -1 && future->isRunning())
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future->d.waitForFinished();
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// Wait for result at target index
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const int targetIndex = (idx == -1) ? future->resultCount() + n : idx + n;
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future->d.waitForResult(targetIndex);
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// After waiting there is either a result or the end was reached
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return (targetIndex < future->resultCount()) ? targetIndex : -1;
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}
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QFuture const * future;
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int index;
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};
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friend class const_iterator;
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typedef const_iterator ConstIterator;
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template<class U = T, typename = QtPrivate::EnableForNonVoid<U>>
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const_iterator begin() const { return const_iterator(this, 0); }
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template<class U = T, typename = QtPrivate::EnableForNonVoid<U>>
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const_iterator constBegin() const { return const_iterator(this, 0); }
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template<class U = T, typename = QtPrivate::EnableForNonVoid<U>>
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const_iterator end() const { return const_iterator(this, -1); }
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template<class U = T, typename = QtPrivate::EnableForNonVoid<U>>
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const_iterator constEnd() const { return const_iterator(this, -1); }
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private:
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friend class QFutureWatcher<T>;
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template<class U>
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friend class QFuture;
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template<class Function, class ResultType, class ParentResultType>
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friend class QtPrivate::Continuation;
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template<class Function, class ResultType>
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friend class QtPrivate::CanceledHandler;
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#ifndef QT_NO_EXCEPTIONS
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template<class Function, class ResultType>
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friend class QtPrivate::FailureHandler;
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#endif
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using QFuturePrivate =
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std::conditional_t<std::is_same_v<T, void>, QFutureInterfaceBase, QFutureInterface<T>>;
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#ifdef QFUTURE_TEST
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public:
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#endif
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mutable QFuturePrivate d;
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};
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template<typename T>
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template<typename U, typename>
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inline T QFuture<T>::result() const
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{
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d.waitForResult(0);
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return d.resultReference(0);
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}
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template<typename T>
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template<typename U, typename>
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inline T QFuture<T>::resultAt(int index) const
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{
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d.waitForResult(index);
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return d.resultReference(index);
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}
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template <typename T>
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inline QFuture<T> QFutureInterface<T>::future()
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{
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return QFuture<T>(this);
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}
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template<class T>
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template<class Function>
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QFuture<typename QFuture<T>::template ResultType<Function>> QFuture<T>::then(Function &&function)
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{
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return then(QtFuture::Launch::Sync, std::forward<Function>(function));
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}
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template<class T>
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template<class Function>
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QFuture<typename QFuture<T>::template ResultType<Function>>
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QFuture<T>::then(QtFuture::Launch policy, Function &&function)
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{
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QFutureInterface<ResultType<Function>> promise(QFutureInterfaceBase::State::Pending);
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QtPrivate::Continuation<std::decay_t<Function>, ResultType<Function>, T>::create(
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std::forward<Function>(function), this, promise, policy);
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return promise.future();
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}
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template<class T>
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template<class Function>
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QFuture<typename QFuture<T>::template ResultType<Function>> QFuture<T>::then(QThreadPool *pool,
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Function &&function)
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{
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QFutureInterface<ResultType<Function>> promise(QFutureInterfaceBase::State::Pending);
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QtPrivate::Continuation<std::decay_t<Function>, ResultType<Function>, T>::create(
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std::forward<Function>(function), this, promise, pool);
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return promise.future();
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}
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template<class T>
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template<class Function>
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QFuture<typename QFuture<T>::template ResultType<Function>> QFuture<T>::then(QObject *context,
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Function &&function)
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{
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QFutureInterface<ResultType<Function>> promise(QFutureInterfaceBase::State::Pending);
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QtPrivate::Continuation<std::decay_t<Function>, ResultType<Function>, T>::create(
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std::forward<Function>(function), this, promise, context);
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return promise.future();
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}
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#ifndef QT_NO_EXCEPTIONS
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template<class T>
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template<class Function, typename>
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QFuture<T> QFuture<T>::onFailed(Function &&handler)
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{
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QFutureInterface<T> promise(QFutureInterfaceBase::State::Pending);
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QtPrivate::FailureHandler<std::decay_t<Function>, T>::create(std::forward<Function>(handler),
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this, promise);
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return promise.future();
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}
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template<class T>
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template<class Function, typename>
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QFuture<T> QFuture<T>::onFailed(QObject *context, Function &&handler)
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{
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QFutureInterface<T> promise(QFutureInterfaceBase::State::Pending);
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QtPrivate::FailureHandler<std::decay_t<Function>, T>::create(std::forward<Function>(handler),
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this, promise, context);
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return promise.future();
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}
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#endif
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template<class T>
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template<class Function, typename>
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QFuture<T> QFuture<T>::onCanceled(Function &&handler)
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{
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QFutureInterface<T> promise(QFutureInterfaceBase::State::Pending);
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QtPrivate::CanceledHandler<std::decay_t<Function>, T>::create(std::forward<Function>(handler),
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this, promise);
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return promise.future();
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}
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template<class T>
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template<class Function, typename>
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QFuture<T> QFuture<T>::onCanceled(QObject *context, Function &&handler)
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{
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QFutureInterface<T> promise(QFutureInterfaceBase::State::Pending);
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QtPrivate::CanceledHandler<std::decay_t<Function>, T>::create(std::forward<Function>(handler),
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this, promise, context);
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return promise.future();
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}
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inline QFuture<void> QFutureInterface<void>::future()
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{
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return QFuture<void>(this);
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}
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Q_DECLARE_SEQUENTIAL_ITERATOR(Future)
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QT_END_NAMESPACE
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#endif // QFUTURE_H
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