spl/WeakReference.h

/*
 *   This file is part of the Standard Portable Library (SPL).
 *
 *   SPL is free software: you can redistribute it and/or modify
 *   it under the terms of the GNU General Public License as published by
 *   the Free Software Foundation, either version 3 of the License, or
 *   (at your option) any later version.
 *
 *   SPL 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 General Public License for more details.
 *
 *   You should have received a copy of the GNU General Public License
 *   along with SPL.  If not, see <http://www.gnu.org/licenses/>.
 */
#ifndef _weakreference_h
#define _weakreference_h

#include <spl/types.h>
#include <spl/Debug.h>
#include <spl/RefCountPtr.h>

template<class BASE, class BASEPTR>
class WeakReference : public IMemoryValidate
{
private:
    _PtrHolder<BASE> *m_ptr;

public:
        inline WeakReference()
        : m_ptr(NULL)
        {
        }

        inline WeakReference(BASEPTR& rptr)
        : m_ptr(rptr.GetHolder())
        {
        }

        virtual ~WeakReference()
        {
        }

        inline operator BASEPTR() const
        {
                return BASEPTR(m_ptr);
        }

        inline WeakReference& operator =(BASEPTR& rptr)
        {
                m_ptr = rptr.GetHolder();
                return *this;
        }

    // value access
    inline BASE* Get() const
    {
                if (NULL == m_ptr)
                {
                        return NULL;
                }
                ASSERT(m_ptr->Count() > 0);
        return m_ptr->ptr;
    }

    inline BASE* operator->() const
    {
                ASSERT(NULL != m_ptr);
                ASSERT(m_ptr->Count() > 0);
        return m_ptr->ptr;
    }

        inline operator BASE&() const
        {
                if (NULL == m_ptr)
                {
                        throw new Exception("NULL pointer");
                }
                ASSERT(m_ptr->Count() > 0);
        return *m_ptr->ptr;
        }

        inline void Clear()
        {
                m_ptr = NULL;
        }

        inline bool IsNull() const
        {
                return m_ptr == NULL;
        }

        inline bool IsNotNull() const
        {
                return ! IsNull();
        }

#if defined(DEBUG) || defined(_DEBUG)
        void CheckMem() const
        {
        }

        void ValidateMem() const
        {
                if (NULL != m_ptr)
                {
                        m_ptr->ValidateThis();
                        ASSERT_MEM(m_ptr->ptr, sizeof(BASE));
                        ValidateType( m_ptr->ptr );
                }
        }
#endif
};

#endif