OpenSceneGraph/include/osg/DeleteHandler
2007-07-09 15:02:03 +00:00

89 lines
3.6 KiB
C++

/* -*-c++-*- OpenSceneGraph - Copyright (C) 1998-2006 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_DELETEHANDLER
#define OSG_DELETEHANDLER 1
#include <osg/Referenced>
#include <list>
namespace osg {
/** Class for override the default delete behavior so that users can implement their own object
* deletion schemes. This might be done to help implement protection of multiple threads from deleting
* objects unintentionally.
* Note, the DeleteHandler cannot itself be reference counted, otherwise it
* would be responsible for deleting itself!
* An static auto_ptr<> is used internally in Referenced.cpp to manage the
* DeleteHandler's memory.*/
class OSG_EXPORT DeleteHandler
{
public:
typedef std::pair<int, const osg::Referenced*> FrameNumberObjectPair;
typedef std::list<FrameNumberObjectPair> ObjectsToDeleteList;
DeleteHandler(int numberOfFramesToRetainObjects=0);
virtual ~DeleteHandler();
/** Set the number of frames to retain objects that are have been requested for deletion.
* When set to zero objects are deleted immediately, by set to 1 there are kept around for an extra frame etc.
* The ability to retain obejcts for several frames is useful to prevent premature deletion when objects
* are stil be used the graphics threads that are using double buffering of rendering data structures with
* non ref_ptr<> pointers to scene graph elements.*/
void setNumFramesToRetainObjects(int numberOfFramesToRetainObjects) { _numFramesToRetainObjects = numberOfFramesToRetainObjects; }
int getNumFramesToRetainObjects() const { return _numFramesToRetainObjects; }
/** Set the current frame numberso that subsequent deletes get tagged as associated with this frame.*/
void setFrameNumber(int frameNumber) { _currentFrameNumber = frameNumber; }
/** Get the current frame number.*/
int getFrameNumber() const { return _currentFrameNumber; }
inline void doDelete(const Referenced* object) { delete object; }
/** Flush objects that ready to be fully deleted.*/
virtual void flush();
/** Flush all objects that the DeleteHandler holds.
* Note, this should only be called if there are no threads running with non ref_ptr<> pointers, such as graphics threads.*/
virtual void flushAll();
/** Request the deletion of an object.
* Depending on users implementation of DeleteHandler, the delete of the object may occur
* straight away or be delayed until doDelete is called.
* The default implementation does a delete straight away.*/
virtual void requestDelete(const osg::Referenced* object);
protected:
DeleteHandler(const DeleteHandler&):
_numFramesToRetainObjects(0),
_currentFrameNumber(0) {}
DeleteHandler operator = (const DeleteHandler&) { return *this; }
int _numFramesToRetainObjects;
int _currentFrameNumber;
OpenThreads::Mutex _mutex;
ObjectsToDeleteList _objectsToDelete;
};
}
#endif