haiku/headers/private/servers/app/SharedObject.h

//------------------------------------------------------------------------------
//	Copyright (c) 2001-2002, Haiku, Inc.
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//	Software is furnished to do so, subject to the following conditions:
//
//	The above copyright notice and this permission notice shall be included in
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//	IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
//	FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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//	DEALINGS IN THE SOFTWARE.
//
//	File Name:		SharedObject.h
//	Author:			DarkWyrm <bpmagic@columbus.rr.com>
//	Description:	This class is used as a base class for other objects which
//  				must be shared. By using this, objects which depend on its 
//					existence can be somewhat sure that the shared object will
//					not be deleted until nothing depends on it.
//  
//------------------------------------------------------------------------------
#ifndef SHAREDOBJ_H_
#define SHAREDOBJ_H_

#include <SupportDefs.h>

/*!
	\class SharedObject SharedObject.h
	\brief Base class for shared objects
	
	SharedObjects track dependencies upon a particular object. In this way, is is
	possible to ensure that a shared resource is not deleted if something else
	needs it. How the dependency tracking is done largely depends on the child class.
*/
class SharedObject {
 public:
							SharedObject()
								: fReferenceCount(0)
								{}
	virtual					~SharedObject()
								{}

	virtual	void			AddDependent()
								{ fReferenceCount++; }
	virtual	void			RemoveDependent()
								{ fReferenceCount--; }
	virtual	bool			HasDependents()
								{ return (fReferenceCount > 0); }
 private:
			uint32			fReferenceCount;
};

#endif