/*
 * Copyright (c) 2009 Dustin Spicuzza <dustin@virtualroadside.com>
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *     * Redistributions of source code must retain the above copyright
 *       notice, this list of conditions and the following disclaimer.
 *     * 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.
 *     * Neither the name of Dustin Spicuzza nor the
 *       names of its contributors may be used to endorse or promote products
 *       derived from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY DUSTIN SPICUZZA ''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 DUSTIN SPICUZZA 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 STATICDELETER_H
#define STATICDELETER_H


/**
	\class StaticDeleter
	\brief Deletes a pointer when this object goes out of scope
	
	Generally, this is useful for implementation of the singleton pattern
	in some form, such as the following example:
	
	\code
	
	SomeType * SomeType::m_instance = NULL;
	StaticDeleter<SomeType> someTypeDeleter(&m_instance);
	
	SomeType * SomeType::GetInstance()
	{
		if (SomeType::m_instance == NULL)
			SomeType::m_instance = new SomeType();
		return SomeType::m_instance;
	}
	
	\endcode
	
	@warning A key assumption made by this class is that the static object
	is only accessed during the normal scope of the program -- ie, the object
	that this class contains a pointer to a pointer to should not be accessed
	by anything that could be called after main() is complete. For some code
	bases, this can be very tricky to enforce.
*/
template <typename TypeToDelete>
class StaticDeleter {
public:

	StaticDeleter(TypeToDelete ** ptr2ptr) :
		m_ptr2ptr(ptr2ptr)
	{}

	~StaticDeleter()
	{
		if (*m_ptr2ptr)
			delete *m_ptr2ptr;
	}

private:
	TypeToDelete ** m_ptr2ptr;
};

#endif