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/*
* Copyright (C) 2005, 2006, 2007, 2008 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 WTF_RefPtr_h
#define WTF_RefPtr_h
#include <algorithm>
#include "AlwaysInline.h"
namespace WTF {
enum PlacementNewAdoptType { PlacementNewAdopt };
template <typename T> class PassRefPtr;
enum HashTableDeletedValueType { HashTableDeletedValue };
template <typename T> class RefPtr {
public:
RefPtr() : m_ptr(0) { }
RefPtr(T* ptr) : m_ptr(ptr) { if (ptr) ptr->ref(); }
RefPtr(const RefPtr& o) : m_ptr(o.m_ptr) { if (T* ptr = m_ptr) ptr->ref(); }
// see comment in PassRefPtr.h for why this takes const reference
template <typename U> RefPtr(const PassRefPtr<U>&);
// Special constructor for cases where we overwrite an object in place.
RefPtr(PlacementNewAdoptType) { }
// Hash table deleted values, which are only constructed and never copied or destroyed.
RefPtr(HashTableDeletedValueType) : m_ptr(hashTableDeletedValue()) { }
bool isHashTableDeletedValue() const { return m_ptr == hashTableDeletedValue(); }
~RefPtr() { if (T* ptr = m_ptr) ptr->deref(); }
template <typename U> RefPtr(const RefPtr<U>& o) : m_ptr(o.get()) { if (T* ptr = m_ptr) ptr->ref(); }
T* get() const { return m_ptr; }
void clear() { if (T* ptr = m_ptr) ptr->deref(); m_ptr = 0; }
PassRefPtr<T> release() { PassRefPtr<T> tmp = adoptRef(m_ptr); m_ptr = 0; return tmp; }
T& operator*() const { return *m_ptr; }
ALWAYS_INLINE T* operator->() const { return m_ptr; }
bool operator!() const { return !m_ptr; }
// This conversion operator allows implicit conversion to bool but not to other integer types.
typedef T* RefPtr::*UnspecifiedBoolType;
operator UnspecifiedBoolType() const { return m_ptr ? &RefPtr::m_ptr : 0; }
RefPtr& operator=(const RefPtr&);
RefPtr& operator=(T*);
RefPtr& operator=(const PassRefPtr<T>&);
template <typename U> RefPtr& operator=(const RefPtr<U>&);
template <typename U> RefPtr& operator=(const PassRefPtr<U>&);
void swap(RefPtr&);
private:
static T* hashTableDeletedValue() { return reinterpret_cast<T*>(-1); }
T* m_ptr;
};
template <typename T> template <typename U> inline RefPtr<T>::RefPtr(const PassRefPtr<U>& o)
: m_ptr(o.releaseRef())
{
}
template <typename T> inline RefPtr<T>& RefPtr<T>::operator=(const RefPtr<T>& o)
{
T* optr = o.get();
if (optr)
optr->ref();
T* ptr = m_ptr;
m_ptr = optr;
if (ptr)
ptr->deref();
return *this;
}
template <typename T> template <typename U> inline RefPtr<T>& RefPtr<T>::operator=(const RefPtr<U>& o)
{
T* optr = o.get();
if (optr)
optr->ref();
T* ptr = m_ptr;
m_ptr = optr;
if (ptr)
ptr->deref();
return *this;
}
template <typename T> inline RefPtr<T>& RefPtr<T>::operator=(T* optr)
{
if (optr)
optr->ref();
T* ptr = m_ptr;
m_ptr = optr;
if (ptr)
ptr->deref();
return *this;
}
template <typename T> inline RefPtr<T>& RefPtr<T>::operator=(const PassRefPtr<T>& o)
{
T* ptr = m_ptr;
m_ptr = o.releaseRef();
if (ptr)
ptr->deref();
return *this;
}
template <typename T> template <typename U> inline RefPtr<T>& RefPtr<T>::operator=(const PassRefPtr<U>& o)
{
T* ptr = m_ptr;
m_ptr = o.releaseRef();
if (ptr)
ptr->deref();
return *this;
}
template <class T> inline void RefPtr<T>::swap(RefPtr<T>& o)
{
std::swap(m_ptr, o.m_ptr);
}
template <class T> inline void swap(RefPtr<T>& a, RefPtr<T>& b)
{
a.swap(b);
}
template <typename T, typename U> inline bool operator==(const RefPtr<T>& a, const RefPtr<U>& b)
{
return a.get() == b.get();
}
template <typename T, typename U> inline bool operator==(const RefPtr<T>& a, U* b)
{
return a.get() == b;
}
template <typename T, typename U> inline bool operator==(T* a, const RefPtr<U>& b)
{
return a == b.get();
}
template <typename T, typename U> inline bool operator!=(const RefPtr<T>& a, const RefPtr<U>& b)
{
return a.get() != b.get();
}
template <typename T, typename U> inline bool operator!=(const RefPtr<T>& a, U* b)
{
return a.get() != b;
}
template <typename T, typename U> inline bool operator!=(T* a, const RefPtr<U>& b)
{
return a != b.get();
}
template <typename T, typename U> inline RefPtr<T> static_pointer_cast(const RefPtr<U>& p)
{
return RefPtr<T>(static_cast<T*>(p.get()));
}
template <typename T, typename U> inline RefPtr<T> const_pointer_cast(const RefPtr<U>& p)
{
return RefPtr<T>(const_cast<T*>(p.get()));
}
template <typename T> inline T* getPtr(const RefPtr<T>& p)
{
return p.get();
}
} // namespace WTF
using WTF::RefPtr;
using WTF::static_pointer_cast;
using WTF::const_pointer_cast;
#endif // WTF_RefPtr_h
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