1/****************************************************************************
2**
3** Copyright (C) 2018 Klarälvdalens Datakonsult AB, a KDAB Group company, info@kdab.com, author Sérgio Martins <sergio.martins@kdab.com>
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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
49QT_BEGIN_NAMESPACE
50
51template <typename F>
52class
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.
56Q_REQUIRED_RESULT
57#endif
58QScopeGuard
59{
60public:
61 explicit QScopeGuard(F &&f) noexcept
62 : m_func(std::move(f))
63 {
64 }
65
66 explicit QScopeGuard(const F &f) noexcept
67 : m_func(f)
68 {
69 }
70
71 QScopeGuard(QScopeGuard &&other) noexcept
72 : m_func(std::move(other.m_func))
73 , m_invoke(qExchange(other.m_invoke, false))
74 {
75 }
76
77 ~QScopeGuard() noexcept
78 {
79 if (m_invoke)
80 m_func();
81 }
82
83 void dismiss() noexcept
84 {
85 m_invoke = false;
86 }
87
88private:
89 Q_DISABLE_COPY(QScopeGuard)
90
91 F m_func;
92 bool m_invoke = true;
93};
94
95#ifdef __cpp_deduction_guides
96template <typename F> QScopeGuard(F(&)()) -> QScopeGuard<F(*)()>;
97#endif
98
99//! [qScopeGuard]
100template <typename F>
101#if __has_cpp_attribute(nodiscard)
102Q_REQUIRED_RESULT
103#endif
104QScopeGuard<typename std::decay<F>::type> qScopeGuard(F &&f)
105{
106 return QScopeGuard<typename std::decay<F>::type>(std::forward<F>(f));
107}
108
109QT_END_NAMESPACE
110
111#endif // QSCOPEGUARD_H
112

source code of qtbase/src/corelib/tools/qscopeguard.h