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100 lines
3.0 KiB
C++
100 lines
3.0 KiB
C++
/*
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* Copyright (C) 2007, 2008, 2010 Apple Inc. All rights reserved.
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* Copyright (C) 2007 Justin Haygood (jhaygood@reaktix.com)
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*
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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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* are met:
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*
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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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* 3. Neither the name of Apple Computer, Inc. ("Apple") nor the names of
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* its contributors may be used to endorse or promote products derived
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* from this software without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY APPLE AND ITS CONTRIBUTORS "AS IS" AND ANY
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* EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
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* WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
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* DISCLAIMED. IN NO EVENT SHALL APPLE OR ITS CONTRIBUTORS BE LIABLE FOR ANY
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* DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
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* (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
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* LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
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* ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
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* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*/
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#ifndef SKY_ENGINE_WTF_THREADSAFEREFCOUNTED_H_
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#define SKY_ENGINE_WTF_THREADSAFEREFCOUNTED_H_
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#include "sky/engine/wtf/Atomics.h"
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#include "sky/engine/wtf/DynamicAnnotations.h"
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#include "sky/engine/wtf/FastAllocBase.h"
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#include "sky/engine/wtf/Noncopyable.h"
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#include "sky/engine/wtf/WTFExport.h"
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namespace WTF {
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class WTF_EXPORT ThreadSafeRefCountedBase {
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WTF_MAKE_NONCOPYABLE(ThreadSafeRefCountedBase);
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WTF_MAKE_FAST_ALLOCATED;
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public:
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ThreadSafeRefCountedBase(int initialRefCount = 1)
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: m_refCount(initialRefCount)
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{
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}
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void ref()
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{
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atomicIncrement(&m_refCount);
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}
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bool hasOneRef()
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{
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return refCount() == 1;
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}
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int refCount() const
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{
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return static_cast<int const volatile &>(m_refCount);
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}
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protected:
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// Returns whether the pointer should be freed or not.
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bool derefBase()
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{
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WTF_ANNOTATE_HAPPENS_BEFORE(&m_refCount);
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if (atomicDecrement(&m_refCount) <= 0) {
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WTF_ANNOTATE_HAPPENS_AFTER(&m_refCount);
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return true;
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}
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return false;
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}
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private:
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int m_refCount;
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};
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template<class T> class ThreadSafeRefCounted : public ThreadSafeRefCountedBase {
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public:
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void deref()
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{
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if (derefBase())
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delete static_cast<T*>(this);
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}
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protected:
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ThreadSafeRefCounted()
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{
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}
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};
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} // namespace WTF
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using WTF::ThreadSafeRefCounted;
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#endif // SKY_ENGINE_WTF_THREADSAFEREFCOUNTED_H_
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