libcruft-util/scoped.hpp

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/*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*
* Copyright 2018, Danny Robson <danny@nerdcruft.net>
*/
#pragma once
namespace util::scoped {
///////////////////////////////////////////////////////////////////////////
/// restores a referenced target variable to its original value at
/// destruction time. the type must be copyable.
template <typename ValueT>
class restore {
public:
restore (ValueT &_target):
m_target (_target),
m_value (_target)
{ ; }
~restore ()
{
m_target = m_value;
}
private:
ValueT &m_target;
ValueT const m_value;
};
//-------------------------------------------------------------------------
template <typename ValueT>
restore (ValueT&) -> restore<ValueT>;
}