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/* NewNet - A networking framework in C++
Copyright (C) 2006-2007 Ingmar K. Steen (iksteen@gmail.com)
Copyright 2008 little blue poney <lbponey@users.sourceforge.net>
This program 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 2 of the License, or
(at your option) any later version.
This program 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 this program; if not, write to the Free Software
Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
#ifndef NEWNET_WEAKREFPTR_H
#define NEWNET_WEAKREFPTR_H
#include "nnbaseptr.h"
#include "nnguardobject.h"
namespace NewNet
{
class Object;
//! A weak reference pointer class.
/*! A weak reference pointer as implemented in this class points at NULL
after the object it once pointed as is deleted. This is done by
registering a callback to the object's guard object so that the
pointer class will be notified when the object is deleted. */
template<class T> class WeakRefPtr : public BasePtr<T>
{
private:
#ifndef DOXYGEN_UNDOCUMENTED
class GuardObjectCallback : public GuardObject::Callback
{
public:
GuardObjectCallback(WeakRefPtr * ptr) : m_Ptr(ptr)
{
}
void operator()(Object * p)
{
m_Ptr->objectDestroyed(p);
}
private:
WeakRefPtr * m_Ptr;
};
GuardObjectCallback * m_GuardObjectCallback;
#endif // DOXYGEN_UNDOCUMENTED
public:
//! Create a new weak reference pointer that points at NULL.
/*! Create a new weak reference pointer that points at NULL. */
WeakRefPtr() : BasePtr<T>()
{
m_GuardObjectCallback = new GuardObjectCallback(this);
}
//! Create a new weak reference pointer that points at t.
/*! Create a new weak reference pointer that points at t. */
WeakRefPtr(T * t) : BasePtr<T>(t)
{
m_GuardObjectCallback = new GuardObjectCallback(this);
if(t)
t->guardObject() += m_GuardObjectCallback;
}
//! Create a new weak reference pointer that points at t.
/*! Create a new weak reference pointer that points at t. */
WeakRefPtr(const WeakRefPtr& t) : BasePtr<T>(t.m_Ptr)
{
m_GuardObjectCallback = new GuardObjectCallback(this);
if(t.m_Ptr)
t.m_Ptr->guardObject() += m_GuardObjectCallback;
}
//! Assign t's object to this pointer.
/*! Assign t's object to this pointer. */
WeakRefPtr& operator=(const WeakRefPtr& t)
{
if(BasePtr<T>::m_Ptr == t.m_Ptr)
return *this;
if(BasePtr<T>::m_Ptr)
BasePtr<T>::m_Ptr->guardObject() -= m_GuardObjectCallback;
BasePtr<T>::m_Ptr = t.m_Ptr;
if(t.m_Ptr)
BasePtr<T>::m_Ptr->guardObject() += m_GuardObjectCallback;
return *this;
}
//! Assign object t to this pointer.
/*! Assign object t to this pointer. */
WeakRefPtr& operator=(T * t)
{
if(BasePtr<T>::m_Ptr == t)
return *this;
if(BasePtr<T>::m_Ptr)
BasePtr<T>::m_Ptr->guardObject() -= m_GuardObjectCallback;
BasePtr<T>::m_Ptr = t;
if(t)
t->guardObject() += m_GuardObjectCallback;
return *this;
}
#ifndef DOXYGEN_UNDOCUMENTED
~WeakRefPtr()
{
if(BasePtr<T>::m_Ptr)
BasePtr<T>::m_Ptr->guardObject() -= m_GuardObjectCallback;
delete m_GuardObjectCallback;
}
#endif // DOXYGEN_UNDOCUMENTED
protected:
#ifndef DOXYGEN_UNDOCUMENTED
void objectDestroyed(Object * p)
{
#ifdef NN_PTR_DEBUG
assert(p == BasePtr<T>::m_Ptr);
#endif
BasePtr<T>::m_Ptr = 0;
}
#endif // DOXYGEN_UNDOCUMENTED
};
}
#undef NN_PTR_CHECK
#endif // NEWNET_REFPTR_H
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