78 lines
2.6 KiB
C++
78 lines
2.6 KiB
C++
/* -*-c++-*- OpenSceneGraph - Copyright (C) 1998-2006 Robert Osfield
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*
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* This library is open source and may be redistributed and/or modified under
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* the terms of the OpenSceneGraph Public License (OSGPL) version 0.0 or
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* (at your option) any later version. The full license is in LICENSE file
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* included with this distribution, and on the openscenegraph.org website.
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*
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* This library is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* OpenSceneGraph Public License for more details.
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*/
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#ifndef OSG_OBSERVER
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#define OSG_OBSERVER 1
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#include <OpenThreads/Mutex>
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#include <osg/Referenced>
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#include <set>
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namespace osg {
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/** Observer base class for tracking when objects are unreferenced (their reference count goes to 0) and are being deleted.*/
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class OSG_EXPORT Observer
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{
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public:
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Observer();
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virtual ~Observer();
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/** objectDeleted is called when the observed object is about to be deleted. The observer will be automatically
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* removed from the observed object's observer set so there is no need for the objectDeleted implementation
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* to call removeObserver() on the observed object. */
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virtual void objectDeleted(void*) {}
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};
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/** Class used by osg::Referenced to track the observers associated with it.*/
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class OSG_EXPORT ObserverSet : public osg::Referenced
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{
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public:
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ObserverSet(const Referenced* observedObject);
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Referenced* getObserverdObject() { return _observedObject; }
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const Referenced* getObserverdObject() const { return _observedObject; }
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/** "Lock" a Referenced object i.e., protect it from being deleted
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* by incrementing its reference count.
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*
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* returns null if object doesn't exist anymore. */
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Referenced* addRefLock();
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inline OpenThreads::Mutex* getObserverSetMutex() const { return &_mutex; }
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void addObserver(Observer* observer);
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void removeObserver(Observer* observer);
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void signalObjectDeleted(void* ptr);
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typedef std::set<Observer*> Observers;
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Observers& getObservers() { return _observers; }
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const Observers& getObservers() const { return _observers; }
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protected:
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ObserverSet(const ObserverSet& rhs): osg::Referenced(rhs) {}
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ObserverSet& operator = (const ObserverSet& /*rhs*/) { return *this; }
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virtual ~ObserverSet();
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mutable OpenThreads::Mutex _mutex;
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Referenced* _observedObject;
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Observers _observers;
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};
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}
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#endif
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