/*]  Copyright (c) 2009-2010, Charles McGarvey  [**************************
**]  All rights reserved.
*
* vi:ts=4 sw=4 tw=75
*
* Distributable under the terms and conditions of the 2-clause BSD license;
* see the file COPYING for a complete text of the license.
*
**************************************************************************/

#ifndef _MOOF_MANAGER_HH_
#define _MOOF_MANAGER_HH_

/**
 * \file manager.hh
 * A manager is a collection of named objects of the same type.  Libraries
 * use reference counting to automagically delete objects which no longer
 * have any interested code.
 */

#include <string>

#include <boost/shared_ptr.hpp>

#include <moof/hash.hh>


namespace moof {


template <class T>
class manager
{
public:

	manager() :
		retain_count_(1) {}

	const std::string& name() const
	{
		return name_;
	}

	static boost::shared_ptr<T> instance(const std::string& name)
	{
		return boost::shared_ptr<T>(retain(name), &release);
	}


private:

	typedef stlplus::hash<std::string,T*,hash_function> ptr_lookup;

	static T* retain(const std::string& name)
	{
		typename ptr_lookup::iterator it = ptr_lookup_.find(name);

		if (it != ptr_lookup_.end())
		{
			++((*it).second->retain_count_);
			return (*it).second;
		}
		else
		{
			T* new_object(new T);
			if (new_object)
			{
				new_object->name_ = name;
				new_object->init(name);
				ptr_lookup_.insert(std::make_pair(name, new_object));
			}
			return new_object; 
		}
	}

	static void release(T* obj)
	{
		if (--(obj->retain_count_) == 0)
		{
			ptr_lookup_.erase(obj->name_);
			delete obj;
		}
	}


	static ptr_lookup	ptr_lookup_;
	std::string			name_;
	unsigned			retain_count_;
};

template <class T>
hash<std::string,T*,hash_function> manager<T>::ptr_lookup_;


} // namespace moof

#endif // _MOOF_MANAGER_HH_