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/*
* Copyright (C) 2006, 2007, 2008, 2009, 2010 Apple Inc. All rights reserved.
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Library General Public
* License as published by the Free Software Foundation; either
* version 2 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Library General Public License for more details.
*
* You should have received a copy of the GNU Library General Public License
* along with this library; see the file COPYING.LIB. If not, write to
* the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
* Boston, MA 02110-1301, USA.
*
*/
#ifndef RefCounted_h
#define RefCounted_h
#include "wtf/Allocator.h"
#include "wtf/Assertions.h"
#include "wtf/InstanceCounter.h"
#include "wtf/Noncopyable.h"
#include "wtf/WTFExport.h"
#if DCHECK_IS_ON()
#define CHECK_REF_COUNTED_LIFECYCLE 1
#include "wtf/ThreadRestrictionVerifier.h"
#else
#define CHECK_REF_COUNTED_LIFECYCLE 0
#endif
namespace WTF {
// This base class holds the non-template methods and attributes.
// The RefCounted class inherits from it reducing the template bloat
// generated by the compiler (technique called template hoisting).
class WTF_EXPORT RefCountedBase {
public:
void ref() const {
#if CHECK_REF_COUNTED_LIFECYCLE
SECURITY_DCHECK(m_verifier.onRef(m_refCount));
DCHECK(!m_adoptionIsRequired);
#endif
SECURITY_DCHECK(!m_deletionHasBegun);
++m_refCount;
}
bool hasOneRef() const {
SECURITY_DCHECK(!m_deletionHasBegun);
#if CHECK_REF_COUNTED_LIFECYCLE
SECURITY_DCHECK(m_verifier.isSafeToUse());
#endif
return m_refCount == 1;
}
int refCount() const {
#if CHECK_REF_COUNTED_LIFECYCLE
SECURITY_DCHECK(m_verifier.isSafeToUse());
#endif
return m_refCount;
}
protected:
RefCountedBase()
: m_refCount(1)
#if ENABLE(SECURITY_ASSERT)
,
m_deletionHasBegun(false)
#endif
#if CHECK_REF_COUNTED_LIFECYCLE
,
m_adoptionIsRequired(true)
#endif
{
}
~RefCountedBase() {
SECURITY_DCHECK(m_deletionHasBegun);
#if CHECK_REF_COUNTED_LIFECYCLE
DCHECK(!m_adoptionIsRequired);
#endif
}
// Returns whether the pointer should be freed or not.
bool derefBase() const {
SECURITY_DCHECK(!m_deletionHasBegun);
#if CHECK_REF_COUNTED_LIFECYCLE
SECURITY_DCHECK(m_verifier.onDeref(m_refCount));
DCHECK(!m_adoptionIsRequired);
#endif
DCHECK_GT(m_refCount, 0);
--m_refCount;
if (!m_refCount) {
#if ENABLE(SECURITY_ASSERT)
m_deletionHasBegun = true;
#endif
return true;
}
return false;
}
#if CHECK_REF_COUNTED_LIFECYCLE
bool deletionHasBegun() const { return m_deletionHasBegun; }
#endif
private:
#if CHECK_REF_COUNTED_LIFECYCLE || ENABLE(SECURITY_ASSERT)
friend void adopted(RefCountedBase*);
#endif
mutable int m_refCount;
#if ENABLE(SECURITY_ASSERT)
mutable bool m_deletionHasBegun;
#endif
#if CHECK_REF_COUNTED_LIFECYCLE
mutable bool m_adoptionIsRequired;
mutable ThreadRestrictionVerifier m_verifier;
#endif
};
#if CHECK_REF_COUNTED_LIFECYCLE || ENABLE(SECURITY_ASSERT)
inline void adopted(RefCountedBase* object) {
if (!object)
return;
SECURITY_DCHECK(!object->m_deletionHasBegun);
#if CHECK_REF_COUNTED_LIFECYCLE
object->m_adoptionIsRequired = false;
#endif
}
#endif
template <typename T>
class RefCounted : public RefCountedBase {
WTF_MAKE_NONCOPYABLE(RefCounted);
// Put |T| in here instead of |RefCounted| so the heap profiler reports |T|
// instead of |RefCounted<T>|. This does not affect overloading of operator
// new.
USING_FAST_MALLOC(T);
public:
void deref() const {
if (derefBase())
delete static_cast<const T*>(this);
}
protected:
#ifdef ENABLE_INSTANCE_COUNTER
RefCounted() { incrementInstanceCount<T>(static_cast<T*>(this)); }
~RefCounted() { decrementInstanceCount<T>(static_cast<T*>(this)); }
#else
RefCounted() {}
#endif
};
} // namespace WTF
using WTF::RefCounted;
#endif // RefCounted_h
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