/*

 *  Copyright (C) 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.

 *

 */

#ifndef WTF_OwnPtr_h

#define WTF_OwnPtr_h

#include "Assertions.h"

#include "Noncopyable.h"

#include "OwnPtrCommon.h"

#include "TypeTraits.h"

#include <algorithm>

#include <memory>

// Remove this once we make all WebKit code compatible with stricter rules about OwnPtr.

#define LOOSE_OWN_PTR

namespace WTF {

    // Unlike most of our smart pointers, OwnPtr can take either the pointer type or the pointed-to type.

    template<typename T> class PassOwnPtr;

    template<typename T> PassOwnPtr<T> adoptPtr(T*);

    template<typename T> class OwnPtr : public Noncopyable {

    public:

        typedef typename RemovePointer<T>::Type ValueType;

        typedef ValueType* PtrType;

        OwnPtr() : m_ptr(0) { }

        // See comment in PassOwnPtr.h for why this takes a const reference.

        template<typename U> OwnPtr(const PassOwnPtr<U>& o);

        // This copy constructor is used implicitly by gcc when it generates

        // transients for assigning a PassOwnPtr<T> object to a stack-allocated

        // OwnPtr<T> object. It should never be called explicitly and gcc

        // should optimize away the constructor when generating code.

        OwnPtr(const OwnPtr<ValueType>&);

        ~OwnPtr() { deleteOwnedPtr(m_ptr); }

        PtrType get() const { return m_ptr; }

        void clear();

        PassOwnPtr<T> release();

        PtrType leakPtr() WARN_UNUSED_RETURN;

        ValueType& operator*() const { ASSERT(m_ptr); return *m_ptr; }

        PtrType operator->() const { ASSERT(m_ptr); return m_ptr; }

        bool operator!() const { return !m_ptr; }

        // This conversion operator allows implicit conversion to bool but not to other integer types.

        typedef PtrType OwnPtr::*UnspecifiedBoolType;

        operator UnspecifiedBoolType() const { return m_ptr ? &OwnPtr::m_ptr : 0; }

        OwnPtr& operator=(const PassOwnPtr<T>&);

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

        void swap(OwnPtr& o) { std::swap(m_ptr, o.m_ptr); }

#ifdef LOOSE_OWN_PTR

        explicit OwnPtr(PtrType ptr) : m_ptr(ptr) { }

        void set(PtrType);

#endif

    private:

        PtrType m_ptr;

    };

    template<typename T> template<typename U> inline OwnPtr<T>::OwnPtr(const PassOwnPtr<U>& o)

        : m_ptr(o.leakPtr())

    {

    }

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

    {

        PtrType ptr = m_ptr;

        m_ptr = 0;

        deleteOwnedPtr(ptr);

    }

    template<typename T> inline PassOwnPtr<T> OwnPtr<T>::release()

    {

        PtrType ptr = m_ptr;

        m_ptr = 0;

        return adoptPtr(ptr);

    }

    template<typename T> inline typename OwnPtr<T>::PtrType OwnPtr<T>::leakPtr()

    {

        PtrType ptr = m_ptr;

        m_ptr = 0;

        return ptr;

    }

#ifdef LOOSE_OWN_PTR

    template<typename T> inline void OwnPtr<T>::set(PtrType ptr)

    {

        ASSERT(!ptr || m_ptr != ptr);

        PtrType oldPtr = m_ptr;

        m_ptr = ptr;

        deleteOwnedPtr(oldPtr);

    }

#endif

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

    {

        PtrType ptr = m_ptr;

        m_ptr = o.leakPtr();

        ASSERT(!ptr || m_ptr != ptr);

        deleteOwnedPtr(ptr);

        return *this;

    }

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

    {

        PtrType ptr = m_ptr;

        m_ptr = o.leakPtr();

        ASSERT(!ptr || m_ptr != ptr);

        deleteOwnedPtr(ptr);

        return *this;

    }

    template<typename T> inline void swap(OwnPtr<T>& a, OwnPtr<T>& b)

    {

        a.swap(b);

    }

    template<typename T, typename U> inline bool operator==(const OwnPtr<T>& a, U* b)

    {

        return a.get() == b; 

    }

    template<typename T, typename U> inline bool operator==(T* a, const OwnPtr<U>& b) 

    {

        return a == b.get(); 

    }

    template<typename T, typename U> inline bool operator!=(const OwnPtr<T>& a, U* b)

    {

        return a.get() != b; 

    }

    template<typename T, typename U> inline bool operator!=(T* a, const OwnPtr<U>& b)

    {

        return a != b.get(); 

    }

    template<typename T> inline typename OwnPtr<T>::PtrType getPtr(const OwnPtr<T>& p)

    {

        return p.get();

    }

} // namespace WTF

using WTF::OwnPtr;

#endif // WTF_OwnPtr_h