widelife.h

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/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You 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.
 */
 
#ifndef _LOG4CXX_HELPERS_WIDELIFE_H
#define _LOG4CXX_HELPERS_WIDELIFE_H
 
#include <log4cxx/log4cxx.h>
#if defined(__cpp_concepts) && __cpp_concepts >= 201500
#include <concepts>
#endif
 
namespace LOG4CXX_NS
{
namespace helpers
{
    

template <class T>
class WideLife
{
public:
    WideLife()
    {       
        new(&storage) T();
    }
    template <class Arg0, class... Args>
#if defined(__cpp_concepts) && __cpp_concepts >= 201500
        requires (!std::same_as<WideLife, Arg0>)
#endif
    WideLife(Arg0&& arg0, Args&&... args)
    {       
        new(&storage) T(std::forward<Arg0>(arg0), std::forward<Args>(args)...);
    }
    
    ~WideLife()
    {
#if LOG4CXX_EVENTS_AT_EXIT
        // keep the holded value alive
#else
        value().~T();
#endif
    }
 
    T& value()
    {
        return *reinterpret_cast<T*>(&storage);
    }
    
    const T& value() const
    {
        return *reinterpret_cast<const T*>(&storage);
    }
    
    operator T&()
    {
        return value();
    }
    
    operator const T&() const
    {
        return value();
    }
 
private:
    alignas(T) char storage[sizeof(T)];
    // Non-copyable
    WideLife(const WideLife& other) = delete;
    WideLife(const WideLife&& other) = delete;
    // Non-assignable
    WideLife& operator=(const WideLife& other) = delete;
    WideLife& operator=(const WideLife&& other) = delete;
}; // class WideLife
}  // namespace helpers
} // namespace log4cx
 
#endif //_LOG4CXX_HELPERS_WIDELIFE_H