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// Copyright (C) 2016 The Qt Company Ltd.
// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR LGPL-3.0-only OR GPL-2.0-only OR GPL-3.0-only
#ifndef QSCOPEDVALUEROLLBACK_H
#define QSCOPEDVALUEROLLBACK_H
#include <QtCore/qglobal.h>
QT_BEGIN_NAMESPACE
template <typename T>
class QScopedValueRollback
{
public:
Q_NODISCARD_CTOR
explicit constexpr QScopedValueRollback(T &var)
: varRef(var), oldValue(var)
{
}
Q_NODISCARD_CTOR
explicit constexpr QScopedValueRollback(T &var, T value)
: varRef(var), oldValue(std::move(var)) // ### C++20: std::exchange(var, std::move(value))
{
var = std::move(value);
}
#if __cpp_constexpr >= 201907L
constexpr
#endif
~QScopedValueRollback()
{
varRef = std::move(oldValue);
}
constexpr void commit()
{
oldValue = varRef;
}
private:
T &varRef;
T oldValue;
Q_DISABLE_COPY_MOVE(QScopedValueRollback)
};
QT_END_NAMESPACE
#endif // QSCOPEDVALUEROLLBACK_H
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