//
// DOMObject.h
//
// $Id: //poco/Main/XML/include/DOM/DOMObject.h#5 $
//
// Definition of the DOMObject class.
//
// Copyright (c) 2004, Guenter Obiltschnig/Applied Informatics.
// All rights reserved.
// 
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions
// are met:
// 
// 1. Redistributions of source code must retain the above copyright
//    notice, this list of conditions and the following disclaimer.
// 
// 2. Redistributions in binary form must reproduce the above copyright
//    notice, this list of conditions and the following disclaimer in the
//    documentation and/or other materials provided with the distribution.
// 
// 3. Redistributions in any form must be accompanied by information on
//    how to obtain complete source code for this software and any
//    accompanying software that uses this software.  The source code
//    must either be included in the distribution or be available for no
//    more than the cost of distribution plus a nominal fee, and must be
//    freely redistributable under reasonable conditions.  For an
//    executable file, complete source code means the source code for all
//    modules it contains.  It does not include source code for modules or
//    files that typically accompany the major components of the operating
//    system on which the executable file runs.
// 
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
// FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
// COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
// INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
// BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
// LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
// CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
// LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
// ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
// POSSIBILITY OF SUCH DAMAGE.
//


#ifndef DOM_DOMObject_INCLUDED
#define DOM_DOMObject_INCLUDED


#ifndef XML_XML_INCLUDED
#include "XML/XML.h"
#endif


XML_BEGIN


class XML_API DOMObject
	/// The base class for all objects in the Document Object Model.
	///
	/// DOMObject defines the rules for memory management
	/// in this implementation of the DOM. Violation of these
	/// rules, which are outlined in the following, results
	/// in memory leaks or dangling pointers.
	///
	/// Every object created by new or by a factory
	/// method (for example, Document::create*) must be released
	/// with a call to release() or autoRelease() when it
	/// is no longer needed.
	///
	/// Every object created by cloning or importing another
	/// object must be released.
	/// For every call to duplicate() there must be a matching
	/// call to release().
	/// An object obtained via any other way must not be
	/// released, except ownership of it has been explicitely
	/// taken with a call to duplicate().
	///
	/// While DOMObjects are safe for use in multithreaded programs,
	/// a DOMObject or one of its subclasses must not be accessed
	/// from multiple threads simultaneously.
{
public:
	DOMObject();
		/// Creates the DOMObject.
		/// The object's reference count is initialized to one.

	void duplicate() const;
		/// Increases the object's reference count.

	void release() const;
		/// Decreases the object's reference count.
		/// If the reference count reaches zero,
		/// the object is deleted.
		
	virtual void autoRelease() = 0;
		/// Adds the object to an appropriate
		/// AutoReleasePool, which is usually the
		/// AutoReleasePool managed by the Document
		/// to which this object belongs.

protected:
	virtual ~DOMObject();
		/// Destroys the DOMObject.

private:
	DOMObject(const DOMObject&);
	DOMObject& operator = (const DOMObject&);
	
	mutable int _rc;
};


//
// inlines
//
inline void DOMObject::duplicate() const
{
	++_rc;
}


inline void DOMObject::release() const
{
	if (--_rc == 0)
		delete this;
}


XML_END


#endif // DOM_DOMObject_INCLUDED