123 lines
4.0 KiB
C++
123 lines
4.0 KiB
C++
/* -*-c++-*- OpenSceneGraph - Copyright (C) 1998-2003 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_REFERENCED
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#define OSG_REFERENCED 1
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#include <osg/Export>
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namespace osg {
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// forward declar, declared after Refenced below.
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class DeleteHandler;
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/** Base class from providing referencing counted objects.*/
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class SG_EXPORT Referenced
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{
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public:
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Referenced()
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{
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_refCount=0;
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}
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Referenced(const Referenced&) {
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_refCount=0;
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}
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inline Referenced& operator = (Referenced&) { return *this; }
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friend class DeleteHandler;
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/** Set a DeleteHandler to which deletion of all referenced counted objects
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* will be delegated to.*/
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static void setDeleteHandler(DeleteHandler* handler);
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/** Get a DeleteHandler.*/
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static DeleteHandler* getDeleteHandler();
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/** increment the reference count by one, indicating that
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this object has another pointer which is referencing it.*/
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inline void ref() const { ++_refCount; }
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/** decrement the reference count by one, indicating that
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a pointer to this object is referencing it. If the
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reference count goes to zero, it is assumed that this object
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is no longer referenced and is automatically deleted.*/
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inline void unref() const;
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/** decrement the reference count by one, indicating that
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a pointer to this object is referencing it. However, do
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not delete it, even if ref count goes to 0. Warning, unref_nodelete()
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should only be called if the user knows exactly who will
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be resonsible for, one should prefer unref() over unref_nodelete()
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as the later can lead to memory leaks.*/
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inline void unref_nodelete() const { --_refCount; }
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/** return the number pointers currently referencing this object. */
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inline int referenceCount() const { return _refCount; }
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protected:
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virtual ~Referenced();
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mutable int _refCount;
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};
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/** Class for override the default delete behavior so that users can implment 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 DeleteHandler
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{
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public:
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virtual ~DeleteHandler() {}
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/** flush any cache of objects that need to be deleted by doing an actual delete.*/
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virtual void flush() {}
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inline void doDelete(const Referenced* object) { delete object; }
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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 Referenced* object) { doDelete(object); }
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};
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inline void Referenced::unref() const
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{
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--_refCount;
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if (_refCount==0)
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{
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if (getDeleteHandler()) getDeleteHandler()->requestDelete(this);
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else delete this;
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}
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else if (_refCount<0)
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{
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throw 2325;
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}
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}
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}
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#endif
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