qt-creator/src/libs/utils/scopedswap.h

/****************************************************************************
**
** Copyright (C) 2015 The Qt Company Ltd.
** Contact: http://www.qt.io/licensing
**
** This file is part of Qt Creator.
**
** Commercial License Usage
** Licensees holding valid commercial Qt licenses may use this file in
** accordance with the commercial license agreement provided with the
** Software or, alternatively, in accordance with the terms contained in
** a written agreement between you and The Qt Company.  For licensing terms and
** conditions see http://www.qt.io/terms-conditions.  For further information
** use the contact form at http://www.qt.io/contact-us.
**
** GNU Lesser General Public License Usage
** Alternatively, this file may be used under the terms of the GNU Lesser
** General Public License version 2.1 or version 3 as published by the Free
** Software Foundation and appearing in the file LICENSE.LGPLv21 and
** LICENSE.LGPLv3 included in the packaging of this file.  Please review the
** following information to ensure the GNU Lesser General Public License
** requirements will be met: https://www.gnu.org/licenses/lgpl.html and
** http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html.
**
** In addition, as a special exception, The Qt Company gives you certain additional
** rights.  These rights are described in The Qt Company LGPL Exception
** version 1.1, included in the file LGPL_EXCEPTION.txt in this package.
**
****************************************************************************/

#ifndef SCOPEDSWAP_H
#define SCOPEDSWAP_H

#if !(__cplusplus > 199711L || __GXX_EXPERIMENTAL_CXX0X__ || _MSC_VER >= 1600 || defined( _LIBCPP_VERSION )) || \
    (defined(__GNUC_LIBSTD__) && ((__GNUC_LIBSTD__-0) * 100 + __GNUC_LIBSTD_MINOR__-0 <= 402))
#  include <algorithm>
#else // C++11
#  include <utility>
#endif


namespace Utils {
/// RAII object to save a value, and restore it when the scope is left.
template<typename T>
class ScopedSwap
{
    T oldValue;
    T &ref;

public:
    ScopedSwap(T &var, T newValue)
        : oldValue(newValue)
        , ref(var)
    {
        std::swap(ref, oldValue);
    }

    ~ScopedSwap()
    {
        std::swap(ref, oldValue);
    }
};

typedef ScopedSwap<bool> ScopedBoolSwap;

} // Utils namespace

#endif // SCOPEDSWAP_H