scoped_set.hpp

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/*
Copyright (c) 2025 acrion innovations GmbH
Authors: Stefan Zipproth, s.zipproth@acrion.ch
 
This file is part of Cbeam, see https://github.com/acrion/cbeam and https://cbeam.org
 
Cbeam is offered under a commercial and under the AGPL license.
For commercial licensing, contact us at https://acrion.ch/sales. For AGPL licensing, see below.
 
AGPL licensing:
 
Cbeam is free software: you can redistribute it and/or modify
it under the terms of the GNU Affero General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.
 
Cbeam is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU Affero General Public License for more details.
 
You should have received a copy of the GNU Affero General Public License
along with Cbeam. If not, see <https://www.gnu.org/licenses/>.
*/
 
#pragma once
 
#include <atomic> // for std::atomic
 
namespace cbeam::lifecycle
{
    template <typename T>
    struct extract_atomic_value_type
    {
        using type = T;
    };
 
    template <typename T>
    struct extract_atomic_value_type<std::atomic<T>>
    {
        using type = T;
    };

    template <typename T>
    class scoped_set
    {
    public:
        using ValueType = typename extract_atomic_value_type<T>::type;

        scoped_set(T& instance, ValueType newVal)
            : _instance(instance)
            , _old_value(instance)
        {
            _instance = newVal;
        }

        virtual ~scoped_set() noexcept
        {
            _instance = _old_value;
        }
 
    private:
        T&        _instance;
        ValueType _old_value;
    };
}