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* Copyright (C) 2009 Apple Inc. All rights reserved.
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* THIS SOFTWARE IS PROVIDED BY APPLE INC. AND ITS CONTRIBUTORS ``AS IS''
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* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
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* THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
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* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR ITS CONTRIBUTORS
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* BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
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* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
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* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
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* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
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* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
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* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF
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* THE POSSIBILITY OF SUCH DAMAGE.
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#include "Collector.h"
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#include <wtf/Noncopyable.h>
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// A smart pointer whose get() function returns 0 for cells awaiting destruction.
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template <typename T> class WeakGCPtr : Noncopyable {
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WeakGCPtr() : m_ptr(0) { }
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WeakGCPtr(T* ptr) { assign(ptr); }
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if (!m_ptr || !Heap::isCellMarked(m_ptr))
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void clear() { m_ptr = 0; }
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T& operator*() const { return *get(); }
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T* operator->() const { return get(); }
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bool operator!() const { return !get(); }
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// This conversion operator allows implicit conversion to bool but not to other integer types.
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operator bool() const { return m_ptr; }
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typedef T* WeakGCPtr::*UnspecifiedBoolType;
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operator UnspecifiedBoolType() const { return get() ? &WeakGCPtr::m_ptr : 0; }
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WeakGCPtr& operator=(T*);
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template <typename T> inline WeakGCPtr<T>& WeakGCPtr<T>::operator=(T* optr)
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template <typename T, typename U> inline bool operator==(const WeakGCPtr<T>& a, const WeakGCPtr<U>& b)
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return a.get() == b.get();
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template <typename T, typename U> inline bool operator==(const WeakGCPtr<T>& a, U* b)
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template <typename T, typename U> inline bool operator==(T* a, const WeakGCPtr<U>& b)
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template <typename T, typename U> inline bool operator!=(const WeakGCPtr<T>& a, const WeakGCPtr<U>& b)
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return a.get() != b.get();
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template <typename T, typename U> inline bool operator!=(const WeakGCPtr<T>& a, U* b)
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template <typename T, typename U> inline bool operator!=(T* a, const WeakGCPtr<U>& b)
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template <typename T, typename U> inline WeakGCPtr<T> static_pointer_cast(const WeakGCPtr<U>& p)
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return WeakGCPtr<T>(static_cast<T*>(p.get()));
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template <typename T, typename U> inline WeakGCPtr<T> const_pointer_cast(const WeakGCPtr<U>& p)
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return WeakGCPtr<T>(const_cast<T*>(p.get()));
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template <typename T> inline T* getPtr(const WeakGCPtr<T>& p)
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#endif // WeakGCPtr_h