include/QtCore/qscopeguard.h

0001 // Copyright (C) 2018 Klarälvdalens Datakonsult AB, a KDAB Group company, info@kdab.com, author Sérgio Martins <sergio.martins@kdab.com>
0002 // Copyright (C) 2019 The Qt Company Ltd.
0003 // SPDX-License-Identifier: LicenseRef-Qt-Commercial OR LGPL-3.0-only OR GPL-2.0-only OR GPL-3.0-only
0004
0005 #ifndef QSCOPEGUARD_H
0006 #define QSCOPEGUARD_H
0007
0008 #include <QtCore/qglobal.h>
0009
0010 #include <type_traits>
0011 #include <utility>
0012
0013 QT_BEGIN_NAMESPACE
0014
0015 template <typename F>
0016 class QScopeGuard
0017 {
0018 public:
0019     Q_NODISCARD_CTOR
0020     explicit QScopeGuard(F &&f) noexcept
0021         : m_func(std::move(f))
0022     {
0023     }
0024
0025     Q_NODISCARD_CTOR
0026     explicit QScopeGuard(const F &f) noexcept
0027         : m_func(f)
0028     {
0029     }
0030
0031     Q_NODISCARD_CTOR
0032     QScopeGuard(QScopeGuard &&other) noexcept
0033         : m_func(std::move(other.m_func))
0034         , m_invoke(std::exchange(other.m_invoke, false))
0035     {
0036     }
0037
0038     ~QScopeGuard() noexcept
0039     {
0040         if (m_invoke)
0041             m_func();
0042     }
0043
0044     void dismiss() noexcept
0045     {
0046         m_invoke = false;
0047     }
0048
0049 private:
0050     Q_DISABLE_COPY(QScopeGuard)
0051
0052     F m_func;
0053     bool m_invoke = true;
0054 };
0055
0056 template <typename F> QScopeGuard(F(&)()) -> QScopeGuard<F(*)()>;
0057
0058 //! [qScopeGuard]
0059 template <typename F>
0060 [[nodiscard]] QScopeGuard<typename std::decay<F>::type> qScopeGuard(F &&f)
0061 {
0062     return QScopeGuard<typename std::decay<F>::type>(std::forward<F>(f));
0063 }
0064
0065 QT_END_NAMESPACE
0066
0067 #endif // QSCOPEGUARD_H