gownptr.h

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/*
 *  Copyright (C) 2006, 2007 Apple Inc. All rights reserved.
 *  Copyright (C) 2008 Collabora Ltd.
 *
 *  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 GOwnPtr_h
#define GOwnPtr_h

#include <algorithm>
#include <glib.h>
#include <wtf/Assertions.h>
#include <wtf/Noncopyable.h>

namespace WTF {
    template <typename T> inline void freeOwnedGPtr(T* ptr) { g_free(reinterpret_cast<void*>(ptr)); }
    template<> void freeOwnedGPtr<GError>(GError*);
    template<> void freeOwnedGPtr<GList>(GList*);
    template<> void freeOwnedGPtr<GCond>(GCond*);
    template<> void freeOwnedGPtr<GMutex>(GMutex*);
    template<> void freeOwnedGPtr<GPatternSpec>(GPatternSpec*);
    template<> void freeOwnedGPtr<GDir>(GDir*);

    template <typename T> class GOwnPtr : Noncopyable {
    public:
        explicit GOwnPtr(T* ptr = 0) : m_ptr(ptr) { }
        ~GOwnPtr() { freeOwnedGPtr(m_ptr); }

        T* get() const { return m_ptr; }
        T* release() { T* ptr = m_ptr; m_ptr = 0; return ptr; }
        T*& outPtr() { ASSERT(!m_ptr); return m_ptr; }

        void set(T* ptr) { ASSERT(!ptr || m_ptr != ptr); freeOwnedGPtr(m_ptr); m_ptr = ptr; }
        void clear() { freeOwnedGPtr(m_ptr); m_ptr = 0; }

        T& operator*() const { ASSERT(m_ptr); return *m_ptr; }
        T* 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 T* GOwnPtr::*UnspecifiedBoolType;
        operator UnspecifiedBoolType() const { return m_ptr ? &GOwnPtr::m_ptr : 0; }

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

    private:
        T* m_ptr;
    };
    
    template <typename T> inline void swap(GOwnPtr<T>& a, GOwnPtr<T>& b) { a.swap(b); }

    template <typename T, typename U> inline bool operator==(const GOwnPtr<T>& a, U* b)
    { 
        return a.get() == b; 
    }
    
    template <typename T, typename U> inline bool operator==(T* a, const GOwnPtr<U>& b) 
    {
        return a == b.get(); 
    }

    template <typename T, typename U> inline bool operator!=(const GOwnPtr<T>& a, U* b)
    {
        return a.get() != b; 
    }

    template <typename T, typename U> inline bool operator!=(T* a, const GOwnPtr<U>& b)
    { 
        return a != b.get(); 
    }
    
    template <typename T> inline typename GOwnPtr<T>::PtrType getPtr(const GOwnPtr<T>& p)
    {
        return p.get();
    }

} // namespace WTF

using WTF::GOwnPtr;

#endif // GOwnPtr_h