/*

 * Copyright (C) 2009, 2010 Apple Inc. All rights reserved.

 *

 * Redistribution and use in source and binary forms, with or without

 * modification, are permitted provided that the following conditions

 * are met:

 * 1. Redistributions of source code must retain the above copyright

 *    notice, this list of conditions and the following disclaimer.

 * 2. Redistributions in binary form must reproduce the above copyright

 *    notice, this list of conditions and the following disclaimer in the

 *    documentation and/or other materials provided with the distribution.

 *

 * THIS SOFTWARE IS PROVIDED BY APPLE INC. ``AS IS'' AND ANY

 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE

 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR

 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL APPLE INC. OR

 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,

 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,

 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR

 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY

 * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT

 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE

 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 

 */

#ifndef WTF_PassOwnPtr_h

#define WTF_PassOwnPtr_h

#include "Assertions.h"

#include "OwnPtrCommon.h"

#include "TypeTraits.h"

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

#define LOOSE_PASS_OWN_PTR

namespace WTF {

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

    template<typename T> class OwnPtr;

    template<typename T> class PassOwnPtr;

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

    template<typename T> class PassOwnPtr {

    public:

        typedef typename RemovePointer<T>::Type ValueType;

        typedef ValueType* PtrType;

        PassOwnPtr() : m_ptr(0) { }

        // It somewhat breaks the type system to allow transfer of ownership out of

        // a const PassOwnPtr. However, it makes it much easier to work with PassOwnPtr

        // temporaries, and we don't have a need to use real const PassOwnPtrs anyway.

        PassOwnPtr(const PassOwnPtr& o) : m_ptr(o.leakPtr()) { }

        template<typename U> PassOwnPtr(const PassOwnPtr<U>& o) : m_ptr(o.leakPtr()) { }

        ~PassOwnPtr() { deleteOwnedPtr(m_ptr); }

        PtrType get() const { return m_ptr; }

        void clear();

        PtrType leakPtr() const 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 PassOwnPtr::*UnspecifiedBoolType;

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

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

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

        template<typename U> friend PassOwnPtr<U> adoptPtr(U*);

#ifdef LOOSE_PASS_OWN_PTR

        PassOwnPtr(PtrType ptr) : m_ptr(ptr) { }

        PassOwnPtr& operator=(PtrType);

#endif

    private:

#ifndef LOOSE_PASS_OWN_PTR

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

#endif

        mutable PtrType m_ptr;

    };

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

    {

        PtrType ptr = m_ptr;

        m_ptr = 0;

        deleteOwnedPtr(ptr);

    }

    template<typename T> inline typename PassOwnPtr<T>::PtrType PassOwnPtr<T>::leakPtr() const

    {

        PtrType ptr = m_ptr;

        m_ptr = 0;

        return ptr;

    }

#ifdef LOOSE_PASS_OWN_PTR

    template<typename T> inline PassOwnPtr<T>& PassOwnPtr<T>::operator=(PtrType optr)

    {

        PtrType ptr = m_ptr;

        m_ptr = optr;

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

        if (ptr)

            deleteOwnedPtr(ptr);

        return *this;

    }

#endif

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

    {

        PtrType ptr = m_ptr;

        m_ptr = optr.leakPtr();

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

        if (ptr)

            deleteOwnedPtr(ptr);

        return *this;

    }

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

    {

        PtrType ptr = m_ptr;

        m_ptr = optr.leakPtr();

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

        if (ptr)

            deleteOwnedPtr(ptr);

        return *this;

    }

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

    {

        return a.get() == b.get(); 

    }

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

    {

        return a.get() == b.get(); 

    }

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

    {

        return a.get() == b.get(); 

    }

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

    {

        return a.get() == b; 

    }

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

    {

        return a == b.get(); 

    }

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

    {

        return a.get() != b.get(); 

    }

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

    {

        return a.get() != b.get(); 

    }

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

    {

        return a.get() != b.get(); 

    }

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

    {

        return a.get() != b; 

    }

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

    {

        return a != b.get(); 

    }

    template<typename T> inline PassOwnPtr<T> adoptPtr(T* ptr)

    {

        return PassOwnPtr<T>(ptr);

    }

    template<typename T, typename U> inline PassOwnPtr<T> static_pointer_cast(const PassOwnPtr<U>& p) 

    {

        return adoptPtr(static_cast<T*>(p.leakPtr()));

    }

    template<typename T, typename U> inline PassOwnPtr<T> const_pointer_cast(const PassOwnPtr<U>& p) 

    {

        return adoptPtr(const_cast<T*>(p.leakPtr()));

    }

    template<typename T> inline T* getPtr(const PassOwnPtr<T>& p)

    {

        return p.get();

    }

} // namespace WTF

using WTF::PassOwnPtr;

using WTF::adoptPtr;

using WTF::const_pointer_cast;

using WTF::static_pointer_cast;

#endif // WTF_PassOwnPtr_h