vmap/libs/modulesystem/singletonmodule.h

/*
   Copyright (C) 2001-2006, William Joseph.
   All Rights Reserved.

   This file is part of GtkRadiant.

   GtkRadiant is free software; you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
   the Free Software Foundation; either version 2 of the License, or
   (at your option) any later version.

   GtkRadiant is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   GNU General Public License for more details.

   You should have received a copy of the GNU General Public License
   along with GtkRadiant; if not, write to the Free Software
   Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
 */

#if !defined( INCLUDED_MODULESYSTEM_SINGLETONMODULE_H )
#define INCLUDED_MODULESYSTEM_SINGLETONMODULE_H

#include "modulesystem.h"
#include <cstddef>
#include "debugging/debugging.h"
#include "modulesystem/moduleregistry.h"
#include "generic/reference.h"

template<typename API, typename Dependencies>
class DefaultAPIConstructor
{
public:
const char* getName(){
	return typename API::Name();
}

API* constructAPI( Dependencies& dependencies ){
	return new API;
}
void destroyAPI( API* api ){
	delete api;
}
};

template<typename API, typename Dependencies>
class DependenciesAPIConstructor
{
public:
const char* getName(){
	return typename API::Name();
}

API* constructAPI( Dependencies& dependencies ){
	return new API( dependencies );
}
void destroyAPI( API* api ){
	delete api;
}
};

class NullDependencies
{
};


template<typename API, typename Dependencies = NullDependencies, typename APIConstructor = DefaultAPIConstructor<API, Dependencies> >
class SingletonModule : public APIConstructor, public Module, public ModuleRegisterable
{
Dependencies* m_dependencies;
API* m_api;
std::size_t m_refcount;
bool m_dependencyCheck;
bool m_cycleCheck;
public:
typedef typename API::Type Type;

SingletonModule()
	: m_dependencies( 0 ), m_api( 0 ), m_refcount( 0 ), m_dependencyCheck( false ), m_cycleCheck( false ){
}
explicit SingletonModule( const APIConstructor& constructor )
	: APIConstructor( constructor ), m_dependencies( 0 ), m_api( 0 ), m_refcount( 0 ), m_dependencyCheck( false ), m_cycleCheck( false ){
}
~SingletonModule(){
	ASSERT_MESSAGE( m_refcount == 0, "module still referenced at shutdown" );
}

void selfRegister(){
	globalModuleServer().registerModule( typename Type::Name(), typename Type::Version(), APIConstructor::getName(), *this );
}

Dependencies& getDependencies(){
	return *m_dependencies;
}
void* getTable(){
	if ( m_api != 0 ) {
		return m_api->getTable();
	}
	return 0;
}
void capture(){
	if ( ++m_refcount == 1 ) {
		globalOutputStream() << "Module Initialising: '" << typename Type::Name() << "' '" << APIConstructor::getName() << "'\n";
		m_dependencies = new Dependencies();
		m_dependencyCheck = !globalModuleServer().getError();
		if ( m_dependencyCheck ) {
			m_api = APIConstructor::constructAPI( *m_dependencies );
			globalOutputStream() << "Module Ready: '" << typename Type::Name() << "' '" << APIConstructor::getName() << "'\n";
		}
		else
		{
			globalOutputStream() << "Module Dependencies Failed: '" << typename Type::Name() << "' '" << APIConstructor::getName() << "'\n";
		}
		m_cycleCheck = true;
	}

	ASSERT_MESSAGE( m_cycleCheck, "cyclic dependency detected" );
}
void release(){
	if ( --m_refcount == 0 ) {
		if ( m_dependencyCheck ) {
			APIConstructor::destroyAPI( m_api );
		}
		delete m_dependencies;
	}
}
};


#endif