/*

 *  Copyright (C) 2005, 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.

 *

 */

// RefPtr and PassRefPtr are documented at http://webkit.org/coding/RefPtr.html

#ifndef WTF_RefPtr_h

#define WTF_RefPtr_h

#include <algorithm>

#include "AlwaysInline.h"

#include "FastAllocBase.h"

#include "PassRefPtr.h"

namespace WTF {

    enum PlacementNewAdoptType { PlacementNewAdopt };

    template <typename T> class PassRefPtr;

    template <typename T> class NonNullPassRefPtr;

    enum HashTableDeletedValueType { HashTableDeletedValue };

    template <typename T> class RefPtr : public FastAllocBase {

    public:

        ALWAYS_INLINE RefPtr() : m_ptr(0) { }

        ALWAYS_INLINE RefPtr(T* ptr) : m_ptr(ptr) { refIfNotNull(ptr); }

        ALWAYS_INLINE RefPtr(const RefPtr& o) : m_ptr(o.m_ptr) { T* ptr = m_ptr; refIfNotNull(ptr); }

        // see comment in PassRefPtr.h for why this takes const reference

        template <typename U> RefPtr(const PassRefPtr<U>&);

        template <typename U> RefPtr(const NonNullPassRefPtr<U>&);

        // Special constructor for cases where we overwrite an object in place.

        ALWAYS_INLINE 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(); }

        ALWAYS_INLINE ~RefPtr() { derefIfNotNull(m_ptr); }

        template <typename U> RefPtr(const RefPtr<U>& o) : m_ptr(o.get()) { T* ptr = m_ptr; refIfNotNull(ptr); }

        T* get() const { return m_ptr; }

        void clear();

        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>&);

        RefPtr& operator=(const NonNullPassRefPtr<T>&);

        template <typename U> RefPtr& operator=(const RefPtr<U>&);

        template <typename U> RefPtr& operator=(const PassRefPtr<U>&);

        template <typename U> RefPtr& operator=(const NonNullPassRefPtr<U>&);

        void swap(RefPtr&);

        static T* hashTableDeletedValue() { return reinterpret_cast<T*>(-1); }

    private:

        T* m_ptr;

    };

    template <typename T> template <typename U> inline RefPtr<T>::RefPtr(const PassRefPtr<U>& o)

        : m_ptr(o.releaseRef())

    {

    }

    template <typename T> template <typename U> inline RefPtr<T>::RefPtr(const NonNullPassRefPtr<U>& o)

        : m_ptr(o.releaseRef())

    {

    }

    template <typename T> inline void RefPtr<T>::clear()

    {

        T* ptr = m_ptr;

        m_ptr = 0;

        derefIfNotNull(ptr);

    }

    template <typename T> inline RefPtr<T>& RefPtr<T>::operator=(const RefPtr<T>& o)

    {

        T* optr = o.get();

        refIfNotNull(optr);

        T* ptr = m_ptr;

        m_ptr = optr;

        derefIfNotNull(ptr);

        return *this;

    }

    template <typename T> template <typename U> inline RefPtr<T>& RefPtr<T>::operator=(const RefPtr<U>& o)

    {

        T* optr = o.get();

        refIfNotNull(optr);

        T* ptr = m_ptr;

        m_ptr = optr;

        derefIfNotNull(ptr);

        return *this;

    }

    template <typename T> inline RefPtr<T>& RefPtr<T>::operator=(T* optr)

    {

        refIfNotNull(optr);

        T* ptr = m_ptr;

        m_ptr = optr;

        derefIfNotNull(ptr);

        return *this;

    }

    template <typename T> inline RefPtr<T>& RefPtr<T>::operator=(const PassRefPtr<T>& o)

    {

        T* ptr = m_ptr;

        m_ptr = o.releaseRef();

        derefIfNotNull(ptr);

        return *this;

    }

    template <typename T> inline RefPtr<T>& RefPtr<T>::operator=(const NonNullPassRefPtr<T>& o)

    {

        T* ptr = m_ptr;

        m_ptr = o.releaseRef();

        derefIfNotNull(ptr);

        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();

        derefIfNotNull(ptr);

        return *this;

    }

    template <typename T> template <typename U> inline RefPtr<T>& RefPtr<T>::operator=(const NonNullPassRefPtr<U>& o)

    {

        T* ptr = m_ptr;

        m_ptr = o.releaseRef();

        derefIfNotNull(ptr);

        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