OpenSceneGraph/include/osg/observer_ptr

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/* -*-c++-*- OpenSceneGraph - Copyright (C) 1998-2005 Robert Osfield
*
* This library is open source and may be redistributed and/or modified under
* the terms of the OpenSceneGraph Public License (OSGPL) version 0.0 or
* (at your option) any later version. The full license is in LICENSE file
* included with this distribution, and on the openscenegraph.org website.
*
* 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
* OpenSceneGraph Public License for more details.
*/
#ifndef OSG_OBSERVER_PTR
#define OSG_OBSERVER_PTR
namespace osg {
class Observer
{
public:
virtual ~Observer() {}
virtual void objectDeleted(void*) {}
};
/** Smart pointer for observed objects, that automatically set pointers to them to null when they deleted.*/
template<class T>
class observer_ptr : public Observer
{
public:
typedef T element_type;
observer_ptr() :_ptr(0L) {}
observer_ptr(T* t):_ptr(t) { if (_ptr) _ptr->addObserver(this); }
observer_ptr(const observer_ptr& rp):Observer(), _ptr(rp._ptr) { if (_ptr) _ptr->addObserver(this); }
~observer_ptr() { if (_ptr) _ptr->removeObserver(this); _ptr=0; }
inline observer_ptr& operator = (const observer_ptr& rp)
{
if (_ptr==rp._ptr) return *this;
if (_ptr) _ptr->removeObserver(this);
_ptr = rp._ptr;
if (_ptr) _ptr->addObserver(this);
return *this;
}
inline observer_ptr& operator = (T* ptr)
{
if (_ptr==ptr) return *this;
if (_ptr) _ptr->removeObserver(this);
_ptr = ptr;
if (_ptr) _ptr->addObserver(this);
return *this;
}
virtual void objectDeleted(void* ptr)
{
if (_ptr==ptr)
{
_ptr = 0;
}
}
// comparison operators for observer_ptr.
inline bool operator == (const observer_ptr& rp) const { return (_ptr==rp._ptr); }
inline bool operator != (const observer_ptr& rp) const { return (_ptr!=rp._ptr); }
inline bool operator < (const observer_ptr& rp) const { return (_ptr<rp._ptr); }
inline bool operator > (const observer_ptr& rp) const { return (_ptr>rp._ptr); }
// comparison operator for const T*.
inline bool operator == (const T* ptr) const { return (_ptr==ptr); }
inline bool operator != (const T* ptr) const { return (_ptr!=ptr); }
inline bool operator < (const T* ptr) const { return (_ptr<ptr); }
inline bool operator > (const T* ptr) const { return (_ptr>ptr); }
inline T& operator*() { return *_ptr; }
inline const T& operator*() const { return *_ptr; }
inline T* operator->() { return _ptr; }
inline const T* operator->() const { return _ptr; }
inline bool operator!() const { return _ptr==0L; }
inline bool valid() const { return _ptr!=0L; }
inline T* get() { return _ptr; }
inline const T* get() const { return _ptr; }
private:
T* _ptr;
};
}
#endif