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/*
* Copyright (c) 2018-2020, Andreas Kling <kling@serenityos.org>
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
*
* 1. Redistributions of source code must retain the above copyright notice, this
* list of conditions and the following disclaimer.
*
* 2. Redistributions in binary form must reproduce the above copyright notice,
* this list of conditions and the following disclaimer in the documentation
* and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
* DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
* SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
* CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#pragma once
#include "Assertions.h"
#include "RefCounted.h"
#include "RefPtr.h"
#define WEAKABLE_DEBUG
namespace AK {
template<typename T>
class Weakable;
template<typename T>
class WeakPtr;
template<typename T>
class WeakLink : public RefCounted<WeakLink<T>> {
friend class Weakable<T>;
public:
T* ptr() { return static_cast<T*>(m_ptr); }
const T* ptr() const { return static_cast<const T*>(m_ptr); }
private:
explicit WeakLink(T& weakable)
: m_ptr(&weakable)
{
}
T* m_ptr;
};
template<typename T>
class Weakable {
private:
class Link;
public:
WeakPtr<T> make_weak_ptr();
protected:
Weakable() {}
~Weakable()
{
#ifdef WEAKABLE_DEBUG
m_being_destroyed = true;
#endif
if (m_link)
m_link->m_ptr = nullptr;
}
private:
RefPtr<WeakLink<T>> m_link;
#ifdef WEAKABLE_DEBUG
bool m_being_destroyed { false };
#endif
};
}
using AK::Weakable;
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