// -*- mode: c++; c-basic-offset: 4 -*-

/*

 *  This file is part of the KDE libraries

 *  Copyright (C) 2005, 2006 Apple Computer, Inc.

 *

 *  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

namespace WTF {

    template<typename T> class RefPtr;

    template<typename T> class PassRefPtr;

    template <typename T> PassRefPtr<T> adoptRef(T*);

    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()) { }

        ~PassRefPtr() { if (T* ptr = m_ptr) ptr->deref(); }

        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; }

        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)() const;

        operator UnspecifiedBoolType() const { return m_ptr ? &PassRefPtr::get : 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;

    };

    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::adoptRef;

using WTF::static_pointer_cast;

using WTF::const_pointer_cast;

#endif // WTF_PassRefPtr_h