/*

 *  Copyright (C) 2005, 2006, 2007, 2008 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 RetainPtr_h

#define RetainPtr_h

#include "HashTraits.h"

#include "TypeTraits.h"

#include <algorithm>

#include <CoreFoundation/CoreFoundation.h>

#ifdef __OBJC__

#import <Foundation/Foundation.h>

#endif

namespace WTF {

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

    // so both RetainPtr<NSDictionary> and RetainPtr<CFDictionaryRef> will work.

    enum AdoptCFTag { AdoptCF };

    enum AdoptNSTag { AdoptNS };

#ifdef __OBJC__

    inline void adoptNSReference(id ptr)

    {

        if (ptr) {

            CFRetain(ptr);

            [ptr release];

        }

    }

#endif

    template <typename T> class RetainPtr {

    public:

        typedef typename RemovePointer<T>::Type ValueType;

        typedef ValueType* PtrType;

        RetainPtr() : m_ptr(0) {}

        RetainPtr(PtrType ptr) : m_ptr(ptr) { if (ptr) CFRetain(ptr); }

        RetainPtr(AdoptCFTag, PtrType ptr) : m_ptr(ptr) { }

        RetainPtr(AdoptNSTag, PtrType ptr) : m_ptr(ptr) { adoptNSReference(ptr); }

        RetainPtr(const RetainPtr& o) : m_ptr(o.m_ptr) { if (PtrType ptr = m_ptr) CFRetain(ptr); }

        // Hash table deleted values, which are only constructed and never copied or destroyed.

        RetainPtr(HashTableDeletedValueType) : m_ptr(hashTableDeletedValue()) { }

        bool isHashTableDeletedValue() const { return m_ptr == hashTableDeletedValue(); }

        ~RetainPtr() { if (PtrType ptr = m_ptr) CFRelease(ptr); }

        template <typename U> RetainPtr(const RetainPtr<U>& o) : m_ptr(o.get()) { if (PtrType ptr = m_ptr) CFRetain(ptr); }

        PtrType get() const { return m_ptr; }

        PtrType releaseRef() { PtrType tmp = m_ptr; m_ptr = 0; return tmp; }

        PtrType 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 PtrType RetainPtr::*UnspecifiedBoolType;

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

        RetainPtr& operator=(const RetainPtr&);

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

        RetainPtr& operator=(PtrType);

        template <typename U> RetainPtr& operator=(U*);

        void adoptCF(PtrType);

        void adoptNS(PtrType);

        void swap(RetainPtr&);

    private:

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

        PtrType m_ptr;

    };

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

    {

        PtrType optr = o.get();

        if (optr)

            CFRetain(optr);

        PtrType ptr = m_ptr;

        m_ptr = optr;

        if (ptr)

            CFRelease(ptr);

        return *this;

    }

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

    {

        PtrType optr = o.get();

        if (optr)

            CFRetain(optr);

        PtrType ptr = m_ptr;

        m_ptr = optr;

        if (ptr)

            CFRelease(ptr);

        return *this;

    }

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

    {

        if (optr)

            CFRetain(optr);

        PtrType ptr = m_ptr;

        m_ptr = optr;

        if (ptr)

            CFRelease(ptr);

        return *this;

    }

    template <typename T> inline void RetainPtr<T>::adoptCF(PtrType optr)

    {

        PtrType ptr = m_ptr;

        m_ptr = optr;

        if (ptr)

            CFRelease(ptr);

    }

    template <typename T> inline void RetainPtr<T>::adoptNS(PtrType optr)

    {

        adoptNSReference(optr);

        PtrType ptr = m_ptr;

        m_ptr = optr;

        if (ptr)

            CFRelease(ptr);

    }

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

    {

        if (optr)

            CFRetain(optr);

        PtrType ptr = m_ptr;

        m_ptr = optr;

        if (ptr)

            CFRelease(ptr);

        return *this;

    }

    template <class T> inline void RetainPtr<T>::swap(RetainPtr<T>& o)

    {

        std::swap(m_ptr, o.m_ptr);

    }

    template <class T> inline void swap(RetainPtr<T>& a, RetainPtr<T>& b)

    {

        a.swap(b);

    }

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

    { 

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

    }

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

    { 

        return a.get() == b; 

    }

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

    {

        return a == b.get(); 

    }

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

    { 

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

    }

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

    {

        return a.get() != b; 

    }

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

    { 

        return a != b.get(); 

    }

    template<typename P> struct HashTraits<RetainPtr<P> > : GenericHashTraits<RetainPtr<P> > {

        static const bool emptyValueIsZero = true;

        static void constructDeletedValue(RetainPtr<P>& slot) { new (&slot) RetainPtr<P>(HashTableDeletedValue); }

        static bool isDeletedValue(const RetainPtr<P>& value) { return value == reinterpret_cast<P*>(-1); }

    };

    template<typename P> struct PtrHash<RetainPtr<P> > : PtrHash<P*> {

        using PtrHash<P*>::hash;

        static unsigned hash(const RetainPtr<P>& key) { return hash(key.get()); }

        using PtrHash<P*>::equal;

        static bool equal(const RetainPtr<P>& a, const RetainPtr<P>& b) { return a == b; }

        static bool equal(P* a, const RetainPtr<P>& b) { return a == b; }

        static bool equal(const RetainPtr<P>& a, P* b) { return a == b; }

    };

    template<typename P> struct DefaultHash<RetainPtr<P> > { typedef PtrHash<RetainPtr<P> > Hash; };

} // namespace WTF

using WTF::AdoptCF;

using WTF::AdoptNS;

using WTF::RetainPtr;

#endif // WTF_RetainPtr_h