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/*
* Copyright (C) 2009, 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. AND ITS 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 APPLE INC. OR ITS 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 Weak_h
#define Weak_h
#include <wtf/Noncopyable.h>
#include <wtf/NullPtr.h>
namespace JSC {
template<typename T> class PassWeak;
class WeakImpl;
class WeakHandleOwner;
// This is a free function rather than a Weak<T> member function so we can put it in Weak.cpp.
JS_EXPORT_PRIVATE void weakClearSlowCase(WeakImpl*&);
template<typename T> class Weak {
WTF_MAKE_NONCOPYABLE(Weak);
public:
Weak()
: m_impl(0)
{
}
explicit Weak(std::nullptr_t)
: m_impl(0)
{
}
explicit Weak(T*, WeakHandleOwner* = 0, void* context = 0);
enum HashTableDeletedValueTag { HashTableDeletedValue };
bool isHashTableDeletedValue() const;
Weak(HashTableDeletedValueTag);
template<typename U> Weak(const PassWeak<U>&);
~Weak()
{
clear();
}
void swap(Weak&);
Weak& operator=(const PassWeak<T>&);
bool operator!() const;
T* operator->() const;
T& operator*() const;
T* get() const;
bool was(T*) const;
// This conversion operator allows implicit conversion to bool but not to other integer types.
typedef void* (Weak::*UnspecifiedBoolType);
operator UnspecifiedBoolType*() const;
PassWeak<T> release();
void clear()
{
if (!m_impl)
return;
weakClearSlowCase(m_impl);
}
private:
static WeakImpl* hashTableDeletedValue();
WeakImpl* m_impl;
};
} // namespace JSC
#endif // Weak_h
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