| 1 | // Copyright (C) 2016 The Qt Company Ltd. |
|---|---|
| 2 | // SPDX-License-Identifier: LicenseRef-Qt-Commercial OR LGPL-3.0-only OR GPL-2.0-only OR GPL-3.0-only |
| 3 | |
| 4 | #ifndef QSCOPEDVALUEROLLBACK_H |
| 5 | #define QSCOPEDVALUEROLLBACK_H |
| 6 | |
| 7 | #include <QtCore/qglobal.h> |
| 8 | |
| 9 | #include <QtCore/q20utility.h> |
| 10 | |
| 11 | QT_BEGIN_NAMESPACE |
| 12 | |
| 13 | template <typename T> |
| 14 | class QScopedValueRollback |
| 15 | { |
| 16 | public: |
| 17 | Q_NODISCARD_CTOR |
| 18 | explicit constexpr QScopedValueRollback(T &var) |
| 19 | : varRef(var), oldValue(var) |
| 20 | { |
| 21 | } |
| 22 | |
| 23 | Q_NODISCARD_CTOR |
| 24 | explicit constexpr QScopedValueRollback(T &var, T value) |
| 25 | : varRef(var), oldValue(q20::exchange(var, std::move(value))) |
| 26 | { |
| 27 | } |
| 28 | |
| 29 | #if __cpp_constexpr >= 201907L |
| 30 | constexpr |
| 31 | #endif |
| 32 | ~QScopedValueRollback() |
| 33 | { |
| 34 | varRef = std::move(oldValue); |
| 35 | } |
| 36 | |
| 37 | constexpr void commit() |
| 38 | { |
| 39 | oldValue = varRef; |
| 40 | } |
| 41 | |
| 42 | private: |
| 43 | T &varRef; |
| 44 | T oldValue; |
| 45 | |
| 46 | Q_DISABLE_COPY_MOVE(QScopedValueRollback) |
| 47 | }; |
| 48 | |
| 49 | QT_END_NAMESPACE |
| 50 | |
| 51 | #endif // QSCOPEDVALUEROLLBACK_H |
| 52 |