89 lines
3.7 KiB
C++
89 lines
3.7 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_DELETEHANDLER
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#define OSG_DELETEHANDLER 1
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#include <osg/Referenced>
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#include <list>
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namespace osg {
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/** Class for override the default delete behavior so that users can implement their own object
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* deletion schemes. This might be done to help implement protection of multiple threads from deleting
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* objects unintentionally.
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* Note, the DeleteHandler cannot itself be reference counted, otherwise it
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* would be responsible for deleting itself!
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* An static auto_ptr<> is used internally in Referenced.cpp to manage the
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* DeleteHandler's memory.*/
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class OSG_EXPORT DeleteHandler
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{
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public:
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typedef std::pair<unsigned int, const osg::Referenced*> FrameNumberObjectPair;
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typedef std::list<FrameNumberObjectPair> ObjectsToDeleteList;
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DeleteHandler(int numberOfFramesToRetainObjects=0);
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virtual ~DeleteHandler();
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/** Set the number of frames to retain objects that are have been requested for deletion.
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* When set to zero objects are deleted immediately, by set to 1 there are kept around for an extra frame etc.
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* The ability to retain objects for several frames is useful to prevent premature deletion when objects
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* are still be used the graphics threads that are using double buffering of rendering data structures with
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* non ref_ptr<> pointers to scene graph elements.*/
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void setNumFramesToRetainObjects(unsigned int numberOfFramesToRetainObjects) { _numFramesToRetainObjects = numberOfFramesToRetainObjects; }
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unsigned int getNumFramesToRetainObjects() const { return _numFramesToRetainObjects; }
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/** Set the current frame number so that subsequent deletes get tagged as associated with this frame.*/
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void setFrameNumber(unsigned int frameNumber) { _currentFrameNumber = frameNumber; }
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/** Get the current frame number.*/
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unsigned int getFrameNumber() const { return _currentFrameNumber; }
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inline void doDelete(const Referenced* object) { delete object; }
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/** Flush objects that ready to be fully deleted.*/
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virtual void flush();
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/** Flush all objects that the DeleteHandler holds.
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* Note, this should only be called if there are no threads running with non ref_ptr<> pointers, such as graphics threads.*/
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virtual void flushAll();
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/** Request the deletion of an object.
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* Depending on users implementation of DeleteHandler, the delete of the object may occur
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* straight away or be delayed until doDelete is called.
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* The default implementation does a delete straight away.*/
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virtual void requestDelete(const osg::Referenced* object);
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protected:
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DeleteHandler(const DeleteHandler&):
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_numFramesToRetainObjects(0),
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_currentFrameNumber(0) {}
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DeleteHandler operator = (const DeleteHandler&) { return *this; }
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unsigned int _numFramesToRetainObjects;
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unsigned int _currentFrameNumber;
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OpenThreads::Mutex _mutex;
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ObjectsToDeleteList _objectsToDelete;
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};
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}
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#endif
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