/** 
 * @file llrefcount.h
 * @brief Base class for reference counted objects for use with LLPointer
 *
 * $LicenseInfo:firstyear=2002&license=viewergpl$
 * 
 * Copyright (c) 2002-2009, Linden Research, Inc.
 * 
 * Second Life Viewer Source Code
 * The source code in this file ("Source Code") is provided by Linden Lab
 * to you under the terms of the GNU General Public License, version 2.0
 * ("GPL"), unless you have obtained a separate licensing agreement
 * ("Other License"), formally executed by you and Linden Lab.  Terms of
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 * online at http://secondlifegrid.net/programs/open_source/licensing/gplv2
 * 
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 * in the file doc/FLOSS-exception.txt in this software distribution, or
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 */
#ifndef LLREFCOUNT_H
#define LLREFCOUNT_H

#include <boost/noncopyable.hpp>

//----------------------------------------------------------------------------
// RefCount objects should generally only be accessed by way of LLPointer<>'s
// see llthread.h for LLThreadSafeRefCount
//----------------------------------------------------------------------------

class LL_COMMON_API LLRefCount
{
protected:
	LLRefCount(const LLRefCount& other);
	LLRefCount& operator=(const LLRefCount&);
	virtual ~LLRefCount(); // use unref()
	
public:
	LLRefCount();

	void ref() const
	{ 
		mRef++; 
	} 

	S32 unref() const
	{
		llassert(mRef >= 1);
		if (0 == --mRef) 
		{
			delete this; 
			return 0;
		}
		return mRef;
	}	

	//NOTE: when passing around a const LLRefCount object, this can return different results
	// at different types, since mRef is mutable
	S32 getNumRefs() const
	{
		return mRef;
	}

private: 
	mutable S32	mRef; 
};

#endif
