1 /**************************************************************************** 2 ** 3 ** Copyright (C) 2018 Klarälvdalens Datakonsult AB, a KDAB Group company, info@kdab.com, author Sérgio Martins <sergio.martins@kdab.com> 4 ** Copyright (C) 2019 The Qt Company Ltd. 5 ** Contact: https://www.qt.io/licensing/ 6 ** 7 ** This file is part of the QtCore module of the Qt Toolkit. 8 ** 9 ** $QT_BEGIN_LICENSE:LGPL$ 10 ** Commercial License Usage 11 ** Licensees holding valid commercial Qt licenses may use this file in 12 ** accordance with the commercial license agreement provided with the 13 ** Software or, alternatively, in accordance with the terms contained in 14 ** a written agreement between you and The Qt Company. For licensing terms 15 ** and conditions see https://www.qt.io/terms-conditions. For further 16 ** information use the contact form at https://www.qt.io/contact-us. 17 ** 18 ** GNU Lesser General Public License Usage 19 ** Alternatively, this file may be used under the terms of the GNU Lesser 20 ** General Public License version 3 as published by the Free Software 21 ** Foundation and appearing in the file LICENSE.LGPL3 included in the 22 ** packaging of this file. Please review the following information to 23 ** ensure the GNU Lesser General Public License version 3 requirements 24 ** will be met: https://www.gnu.org/licenses/lgpl-3.0.html. 25 ** 26 ** GNU General Public License Usage 27 ** Alternatively, this file may be used under the terms of the GNU 28 ** General Public License version 2.0 or (at your option) the GNU General 29 ** Public license version 3 or any later version approved by the KDE Free 30 ** Qt Foundation. The licenses are as published by the Free Software 31 ** Foundation and appearing in the file LICENSE.GPL2 and LICENSE.GPL3 32 ** included in the packaging of this file. Please review the following 33 ** information to ensure the GNU General Public License requirements will 34 ** be met: https://www.gnu.org/licenses/gpl-2.0.html and 35 ** https://www.gnu.org/licenses/gpl-3.0.html. 36 ** 37 ** $QT_END_LICENSE$ 38 ** 39 ****************************************************************************/ 40 41 #ifndef QSCOPEGUARD_H 42 #define QSCOPEGUARD_H 43 44 #include <QtCore/qglobal.h> 45 46 #include <type_traits> 47 #include <utility> 48 49 QT_BEGIN_NAMESPACE 50 51 template <typename F> 52 class 53 #if __has_cpp_attribute(nodiscard) 54 // Q_REQUIRED_RESULT can be defined as __warn_unused_result__ or as [[nodiscard]] 55 // but the 1st one has some limitations for example can be placed only on functions. 56 Q_REQUIRED_RESULT 57 #endif 58 QScopeGuard 59 { 60 public: QScopeGuard(F && f)61 explicit QScopeGuard(F &&f) noexcept 62 : m_func(std::move(f)) 63 { 64 } 65 QScopeGuard(const F & f)66 explicit QScopeGuard(const F &f) noexcept 67 : m_func(f) 68 { 69 } 70 QScopeGuard(QScopeGuard && other)71 QScopeGuard(QScopeGuard &&other) noexcept 72 : m_func(std::move(other.m_func)) 73 , m_invoke(qExchange(other.m_invoke, false)) 74 { 75 } 76 ~QScopeGuard()77 ~QScopeGuard() noexcept 78 { 79 if (m_invoke) 80 m_func(); 81 } 82 dismiss()83 void dismiss() noexcept 84 { 85 m_invoke = false; 86 } 87 88 private: 89 Q_DISABLE_COPY(QScopeGuard) 90 91 F m_func; 92 bool m_invoke = true; 93 }; 94 95 #ifdef __cpp_deduction_guides 96 template <typename F> QScopeGuard(F(&)()) -> QScopeGuard<F(*)()>; 97 #endif 98 99 //! [qScopeGuard] 100 template <typename F> 101 #if __has_cpp_attribute(nodiscard) 102 Q_REQUIRED_RESULT 103 #endif qScopeGuard(F && f)104QScopeGuard<typename std::decay<F>::type> qScopeGuard(F &&f) 105 { 106 return QScopeGuard<typename std::decay<F>::type>(std::forward<F>(f)); 107 } 108 109 QT_END_NAMESPACE 110 111 #endif // QSCOPEGUARD_H 112