1/****************************************************************************
2**
3** Copyright (C) 2018 Klarälvdalens Datakonsult AB, a KDAB Group company, info@kdab.com, author Sérgio Martins <sergio.martins@kdab.com>
4** Contact: https://www.qt.io/licensing/
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38****************************************************************************/
39
40#ifndef QSCOPEGUARD_H
41#define QSCOPEGUARD_H
42
43#include <QtCore/qglobal.h>
44
45
46QT_BEGIN_NAMESPACE
47
48
49template <typename F> class QScopeGuard;
50template <typename F> QScopeGuard<F> qScopeGuard(F f);
51
52template <typename F>
53class
54#if QT_HAS_CPP_ATTRIBUTE(nodiscard)
55// Q_REQUIRED_RESULT can be defined as __warn_unused_result__ or as [[nodiscard]]
56// but the 1st one has some limitations for example can be placed only on functions.
57Q_REQUIRED_RESULT
58#endif
59QScopeGuard
60{
61public:
62 QScopeGuard(QScopeGuard &&other) noexcept
63 : m_func(std::move(other.m_func))
64 , m_invoke(qExchange(other.m_invoke, false))
65 {
66 }
67
68 ~QScopeGuard()
69 {
70 if (m_invoke)
71 m_func();
72 }
73
74 void dismiss() noexcept
75 {
76 m_invoke = false;
77 }
78
79private:
80 explicit QScopeGuard(F &&f) noexcept
81 : m_func(std::move(f))
82 {
83 }
84
85 Q_DISABLE_COPY(QScopeGuard)
86
87 F m_func;
88 bool m_invoke = true;
89 friend QScopeGuard qScopeGuard<F>(F);
90};
91
92
93template <typename F>
94#if QT_HAS_CPP_ATTRIBUTE(nodiscard)
95Q_REQUIRED_RESULT
96#endif
97QScopeGuard<F> qScopeGuard(F f)
98{
99 return QScopeGuard<F>(std::move(f));
100}
101
102QT_END_NAMESPACE
103
104#endif // QSCOPEGUARD_H
105