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/*
* Copyright (C) 2005, 2006, 2007 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_PassRefPtr_h
#define WTF_PassRefPtr_h
#include "AlwaysInline.h"
namespace WTF {
template<typename T> class RefPtr;
template<typename T> class PassRefPtr;
template <typename T> PassRefPtr<T> adoptRef(T*);
// Remove inline for winscw compiler to prevent the compiler agressively resolving
// T::deref(), which will fail compiling when PassRefPtr<T> is used as class member
// or function arguments before T is defined.
template<typename T>
#if !COMPILER(WINSCW)
inline
#endif
void derefIfNotNull(T* ptr)
{
if (UNLIKELY(ptr != 0))
ptr->deref();
}
template<typename T> class PassRefPtr {
public:
PassRefPtr() : m_ptr(0) {}
PassRefPtr(T* ptr) : m_ptr(ptr) { if (ptr) ptr->ref(); }
// It somewhat breaks the type system to allow transfer of ownership out of
// a const PassRefPtr. However, it makes it much easier to work with PassRefPtr
// temporaries, and we don't really have a need to use real const PassRefPtrs
// anyway.
PassRefPtr(const PassRefPtr& o) : m_ptr(o.releaseRef()) {}
template <typename U> PassRefPtr(const PassRefPtr<U>& o) : m_ptr(o.releaseRef()) { }
ALWAYS_INLINE ~PassRefPtr() { derefIfNotNull<T>(m_ptr); }
template <class U>
PassRefPtr(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; }
T* releaseRef() const { T* tmp = m_ptr; m_ptr = 0; return tmp; }
T& operator*() const { return *m_ptr; }
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* (PassRefPtr::*UnspecifiedBoolType);
operator UnspecifiedBoolType() const { return m_ptr ? &PassRefPtr::m_ptr : 0; }
PassRefPtr& operator=(T*);
PassRefPtr& operator=(const PassRefPtr&);
template <typename U> PassRefPtr& operator=(const PassRefPtr<U>&);
template <typename U> PassRefPtr& operator=(const RefPtr<U>&);
friend PassRefPtr adoptRef<T>(T*);
private:
// adopting constructor
PassRefPtr(T* ptr, bool) : m_ptr(ptr) {}
mutable T* m_ptr;
};
// NonNullPassRefPtr: Optimized for passing non-null pointers. A NonNullPassRefPtr
// begins life non-null, and can only become null through a call to releaseRef()
// or clear().
// FIXME: NonNullPassRefPtr could just inherit from PassRefPtr. However,
// if we use inheritance, GCC's optimizer fails to realize that destruction
// of a released NonNullPassRefPtr is a no-op. So, for now, just copy the
// most important code from PassRefPtr.
template <typename T> class NonNullPassRefPtr {
public:
NonNullPassRefPtr(T* ptr)
: m_ptr(ptr)
{
ASSERT(m_ptr);
m_ptr->ref();
}
template <class U> NonNullPassRefPtr(const RefPtr<U>& o)
: m_ptr(o.get())
{
ASSERT(m_ptr);
m_ptr->ref();
}
NonNullPassRefPtr(const NonNullPassRefPtr& o)
: m_ptr(o.releaseRef())
{
ASSERT(m_ptr);
}
template <class U> NonNullPassRefPtr(const NonNullPassRefPtr<U>& o)
: m_ptr(o.releaseRef())
{
ASSERT(m_ptr);
}
template <class U> NonNullPassRefPtr(const PassRefPtr<U>& o)
: m_ptr(o.releaseRef())
{
ASSERT(m_ptr);
}
ALWAYS_INLINE ~NonNullPassRefPtr() { derefIfNotNull(m_ptr); }
T* get() const { return m_ptr; }
void clear() { derefIfNotNull(m_ptr); m_ptr = 0; }
T* releaseRef() const { T* tmp = m_ptr; m_ptr = 0; return tmp; }
T& operator*() const { return *m_ptr; }
T* operator->() const { return m_ptr; }
private:
mutable T* m_ptr;
};
template <typename T> template <typename U> inline PassRefPtr<T>& PassRefPtr<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 PassRefPtr<T>& PassRefPtr<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 PassRefPtr<T>& PassRefPtr<T>::operator=(const PassRefPtr<T>& ref)
{
T* ptr = m_ptr;
m_ptr = ref.releaseRef();
if (ptr)
ptr->deref();
return *this;
}
template <typename T> template <typename U> inline PassRefPtr<T>& PassRefPtr<T>::operator=(const PassRefPtr<U>& ref)
{
T* ptr = m_ptr;
m_ptr = ref.releaseRef();
if (ptr)
ptr->deref();
return *this;
}
template <typename T, typename U> inline bool operator==(const PassRefPtr<T>& a, const PassRefPtr<U>& b)
{
return a.get() == b.get();
}
template <typename T, typename U> inline bool operator==(const PassRefPtr<T>& a, const RefPtr<U>& b)
{
return a.get() == b.get();
}
template <typename T, typename U> inline bool operator==(const RefPtr<T>& a, const PassRefPtr<U>& b)
{
return a.get() == b.get();
}
template <typename T, typename U> inline bool operator==(const PassRefPtr<T>& a, U* b)
{
return a.get() == b;
}
template <typename T, typename U> inline bool operator==(T* a, const PassRefPtr<U>& b)
{
return a == b.get();
}
template <typename T, typename U> inline bool operator!=(const PassRefPtr<T>& a, const PassRefPtr<U>& b)
{
return a.get() != b.get();
}
template <typename T, typename U> inline bool operator!=(const PassRefPtr<T>& a, const RefPtr<U>& b)
{
return a.get() != b.get();
}
template <typename T, typename U> inline bool operator!=(const RefPtr<T>& a, const PassRefPtr<U>& b)
{
return a.get() != b.get();
}
template <typename T, typename U> inline bool operator!=(const PassRefPtr<T>& a, U* b)
{
return a.get() != b;
}
template <typename T, typename U> inline bool operator!=(T* a, const PassRefPtr<U>& b)
{
return a != b.get();
}
template <typename T> inline PassRefPtr<T> adoptRef(T* p)
{
return PassRefPtr<T>(p, true);
}
template <typename T, typename U> inline PassRefPtr<T> static_pointer_cast(const PassRefPtr<U>& p)
{
return adoptRef(static_cast<T*>(p.releaseRef()));
}
template <typename T, typename U> inline PassRefPtr<T> const_pointer_cast(const PassRefPtr<U>& p)
{
return adoptRef(const_cast<T*>(p.releaseRef()));
}
template <typename T> inline T* getPtr(const PassRefPtr<T>& p)
{
return p.get();
}
} // namespace WTF
using WTF::PassRefPtr;
using WTF::NonNullPassRefPtr;
using WTF::adoptRef;
using WTF::static_pointer_cast;
using WTF::const_pointer_cast;
#endif // WTF_PassRefPtr_h
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