/* | |
* Copyright (C) 2006, 2007, 2009 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 TreeShared_h | |
#define TreeShared_h | |
#include <wtf/Assertions.h> | |
#include <wtf/Noncopyable.h> | |
#ifndef NDEBUG | |
#include <wtf/Threading.h> | |
#endif | |
namespace WebCore { | |
template<class T> class TreeShared : public Noncopyable { | |
public: | |
TreeShared(int initialRefCount = 1) | |
: m_refCount(initialRefCount) | |
, m_parent(0) | |
{ | |
ASSERT(isMainThread()); | |
#ifndef NDEBUG | |
m_deletionHasBegun = false; | |
m_inRemovedLastRefFunction = false; | |
#endif | |
} | |
virtual ~TreeShared() | |
{ | |
ASSERT(isMainThread()); | |
ASSERT(!m_refCount); | |
ASSERT(m_deletionHasBegun); | |
} | |
void ref() | |
{ | |
ASSERT(isMainThread()); | |
ASSERT(!m_deletionHasBegun); | |
ASSERT(!m_inRemovedLastRefFunction); | |
++m_refCount; | |
} | |
void deref() | |
{ | |
ASSERT(isMainThread()); | |
ASSERT(m_refCount >= 0); | |
ASSERT(!m_deletionHasBegun); | |
ASSERT(!m_inRemovedLastRefFunction); | |
if (--m_refCount <= 0 && !m_parent) { | |
#ifndef NDEBUG | |
m_inRemovedLastRefFunction = true; | |
#endif | |
removedLastRef(); | |
} | |
} | |
bool hasOneRef() const | |
{ | |
ASSERT(!m_deletionHasBegun); | |
ASSERT(!m_inRemovedLastRefFunction); | |
return m_refCount == 1; | |
} | |
int refCount() const | |
{ | |
return m_refCount; | |
} | |
void setParent(T* parent) | |
{ | |
ASSERT(isMainThread()); | |
m_parent = parent; | |
} | |
T* parent() const | |
{ | |
ASSERT(isMainThread()); | |
return m_parent; | |
} | |
#ifndef NDEBUG | |
bool m_deletionHasBegun; | |
bool m_inRemovedLastRefFunction; | |
#endif | |
private: | |
virtual void removedLastRef() | |
{ | |
#ifndef NDEBUG | |
m_deletionHasBegun = true; | |
#endif | |
delete this; | |
} | |
int m_refCount; | |
T* m_parent; | |
}; | |
} | |
#endif // TreeShared.h |