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/*
* Copyright (C) 2012, 2013 Apple Inc. 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 APPLE INC. ``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 APPLE INC. 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.
*/
#ifndef PassWeak_h
#define PassWeak_h
#include "JSCell.h"
#include "WeakSetInlines.h"
#include <wtf/Assertions.h>
#include <wtf/NullPtr.h>
#include <wtf/TypeTraits.h>
namespace JSC {
template<typename T> class PassWeak;
template<typename T> PassWeak<T> adoptWeak(WeakImpl*);
template<typename T> class PassWeak {
public:
PassWeak();
PassWeak(std::nullptr_t);
PassWeak(T*, WeakHandleOwner* = 0, void* context = 0);
// It somewhat breaks the type system to allow transfer of ownership out of
// a const PassWeak. However, it makes it much easier to work with PassWeak
// temporaries, and we don't have a need to use real const PassWeaks anyway.
PassWeak(const PassWeak&);
template<typename U> PassWeak(const PassWeak<U>&);
~PassWeak();
T* operator->() const;
T& operator*() const;
T* get() const;
bool operator!() const;
// This conversion operator allows implicit conversion to bool but not to other integer types.
typedef void* (PassWeak::*UnspecifiedBoolType);
operator UnspecifiedBoolType*() const;
WeakImpl* leakImpl() const WARN_UNUSED_RETURN;
private:
friend PassWeak adoptWeak<T>(WeakImpl*);
explicit PassWeak(WeakImpl*);
WeakImpl* m_impl;
};
template<typename T> inline PassWeak<T>::PassWeak()
: m_impl(0)
{
}
template<typename T> inline PassWeak<T>::PassWeak(std::nullptr_t)
: m_impl(0)
{
}
template<typename T> inline PassWeak<T>::PassWeak(T* cell, WeakHandleOwner* weakOwner, void* context)
: m_impl(cell ? WeakSet::allocate(cell, weakOwner, context) : 0)
{
}
template<typename T> inline PassWeak<T>::PassWeak(const PassWeak& o)
: m_impl(o.leakImpl())
{
}
template<typename T> template<typename U> inline PassWeak<T>::PassWeak(const PassWeak<U>& o)
: m_impl(o.leakImpl())
{
}
template<typename T> inline PassWeak<T>::~PassWeak()
{
if (!m_impl)
return;
WeakSet::deallocate(m_impl);
}
template<typename T> inline T* PassWeak<T>::operator->() const
{
ASSERT(m_impl && m_impl->state() == WeakImpl::Live);
return jsCast<T*>(m_impl->jsValue().asCell());
}
template<typename T> inline T& PassWeak<T>::operator*() const
{
ASSERT(m_impl && m_impl->state() == WeakImpl::Live);
return *jsCast<T*>(m_impl->jsValue().asCell());
}
template<typename T> inline T* PassWeak<T>::get() const
{
if (!m_impl || m_impl->state() != WeakImpl::Live)
return 0;
return jsCast<T*>(m_impl->jsValue().asCell());
}
template<typename T> inline bool PassWeak<T>::operator!() const
{
return !m_impl || m_impl->state() != WeakImpl::Live || !m_impl->jsValue();
}
template<typename T> inline PassWeak<T>::operator UnspecifiedBoolType*() const
{
return reinterpret_cast<UnspecifiedBoolType*>(!!*this);
}
template<typename T> inline PassWeak<T>::PassWeak(WeakImpl* impl)
: m_impl(impl)
{
}
template<typename T> inline WeakImpl* PassWeak<T>::leakImpl() const
{
WeakImpl* tmp = 0;
std::swap(tmp, const_cast<WeakImpl*&>(m_impl));
return tmp;
}
template<typename T> PassWeak<T> inline adoptWeak(WeakImpl* impl)
{
return PassWeak<T>(impl);
}
template<typename T, typename U> inline bool operator==(const PassWeak<T>& a, const PassWeak<U>& b)
{
return a.get() == b.get();
}
template<typename T, typename U> inline bool operator==(const PassWeak<T>& a, const Weak<U>& b)
{
return a.get() == b.get();
}
template<typename T, typename U> inline bool operator==(const Weak<T>& a, const PassWeak<U>& b)
{
return a.get() == b.get();
}
template<typename T, typename U> inline bool operator==(const PassWeak<T>& a, U* b)
{
return a.get() == b;
}
template<typename T, typename U> inline bool operator==(T* a, const PassWeak<U>& b)
{
return a == b.get();
}
template<typename T, typename U> inline bool operator!=(const PassWeak<T>& a, const PassWeak<U>& b)
{
return a.get() != b.get();
}
template<typename T, typename U> inline bool operator!=(const PassWeak<T>& a, const Weak<U>& b)
{
return a.get() != b.get();
}
template<typename T, typename U> inline bool operator!=(const Weak<T>& a, const PassWeak<U>& b)
{
return a.get() != b.get();
}
template<typename T, typename U> inline bool operator!=(const PassWeak<T>& a, U* b)
{
return a.get() != b;
}
template<typename T, typename U> inline bool operator!=(T* a, const PassWeak<U>& b)
{
return a != b.get();
}
} // namespace JSC
#endif // PassWeak_h
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