ladybird/AK/WeakPtr.h

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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.
*/
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#pragma once
#include <AK/LogStream.h>
#include <AK/Weakable.h>
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namespace AK {
template<typename T>
class OwnPtr;
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template<typename T>
class WeakPtr {
friend class Weakable<T>;
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public:
WeakPtr() {}
WeakPtr(std::nullptr_t) {}
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template<typename U>
WeakPtr(WeakPtr<U>&& other)
: m_link(reinterpret_cast<WeakLink<T>*>(other.take_link().ptr()))
{
}
template<typename U>
WeakPtr& operator=(WeakPtr<U>&& other)
{
m_link = reinterpret_cast<WeakLink<T>*>(other.take_link().ptr());
return *this;
}
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operator bool() const { return ptr(); }
T* ptr() { return m_link ? m_link->ptr() : nullptr; }
const T* ptr() const { return m_link ? m_link->ptr() : nullptr; }
T* operator->() { return ptr(); }
const T* operator->() const { return ptr(); }
T& operator*() { return *ptr(); }
const T& operator*() const { return *ptr(); }
operator const T*() const { return ptr(); }
operator T*() { return ptr(); }
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bool is_null() const { return !m_link || !m_link->ptr(); }
void clear() { m_link = nullptr; }
RefPtr<WeakLink<T>> take_link() { return move(m_link); }
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bool operator==(const OwnPtr<T>& other) const { return ptr() == other.ptr(); }
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private:
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WeakPtr(RefPtr<WeakLink<T>> link)
: m_link(move(link))
{
}
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RefPtr<WeakLink<T>> m_link;
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};
template<typename T>
inline WeakPtr<T> Weakable<T>::make_weak_ptr()
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{
#ifdef DEBUG
ASSERT(!m_being_destroyed);
#endif
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if (!m_link)
m_link = adopt(*new WeakLink<T>(static_cast<T&>(*this)));
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return WeakPtr<T>(m_link);
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}
template<typename T>
inline const LogStream& operator<<(const LogStream& stream, const WeakPtr<T>& value)
{
return stream << value.ptr();
}
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}
using AK::WeakPtr;