vmap/include/modulesystem.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_H )
#define INCLUDED_MODULESYSTEM_H

#include "globaldefs.h"
#include "generic/static.h"
#include "debugging/debugging.h"

#if GDEF_OS_WINDOWS
#define RADIANT_DLLEXPORT __declspec(dllexport)
#define RADIANT_DLLIMPORT __declspec(dllimport)
#else
#define RADIANT_DLLEXPORT __attribute__((visibility("default")))
#define RADIANT_DLLIMPORT
#endif


class Module
{
public:
virtual void capture() = 0;
virtual void release() = 0;
virtual void* getTable() = 0;
};

inline void* Module_getTable( Module& module ){
	return module.getTable();
}

class TextOutputStream;
class DebugMessageHandler;

class ModuleServer
{
public:
class Visitor
{
public:
virtual void visit( const char* name, Module& module ) const = 0;
};

virtual void setError( bool error ) = 0;
virtual bool getError() const = 0;

virtual TextOutputStream& getOutputStream() = 0;
virtual TextOutputStream& getErrorStream() = 0;
virtual DebugMessageHandler& getDebugMessageHandler() = 0;

virtual void registerModule( const char* type, int version, const char* name, Module& module ) = 0;
virtual Module* findModule( const char* type, int version, const char* name ) const = 0;
virtual void foreachModule( const char* type, int version, const Visitor& visitor ) = 0;
};

class ModuleServerHolder
{
ModuleServer* m_server;
public:
ModuleServerHolder()
	: m_server( 0 ){
}
void set( ModuleServer& server ){
	m_server = &server;
}
ModuleServer& get(){
	return *m_server;
}
};

typedef Static<ModuleServerHolder> GlobalModuleServer;

inline ModuleServer& globalModuleServer(){
	return GlobalModuleServer::instance().get();
}


inline void initialiseModule( ModuleServer& server ){
	GlobalErrorStream::instance().setOutputStream( server.getErrorStream() );
	GlobalOutputStream::instance().setOutputStream( server.getOutputStream() );
	GlobalDebugMessageHandler::instance().setHandler( server.getDebugMessageHandler() );
	GlobalModuleServer::instance().set( server );
}



template<typename Type>
class Modules
{
public:
class Visitor
{
public:
virtual void visit( const char* name, const Type& table ) const = 0;
};

virtual Type* findModule( const char* name ) = 0;
virtual void foreachModule( const Visitor& visitor ) = 0;
};

#include "debugging/debugging.h"

template<typename Type>
class ModuleRef
{
Module* m_module;
Type* m_table;
public:
ModuleRef( const char* name ) : m_table( 0 ){
	if ( !globalModuleServer().getError() ) {
		m_module = globalModuleServer().findModule( typename Type::Name(), typename Type::Version(), name );
		if ( m_module == 0 ) {
			globalModuleServer().setError( true );
			globalErrorStream() << "ModuleRef::initialise: type=" << makeQuoted( typename Type::Name() ) << " version=" << makeQuoted( typename Type::Version() ) << " name=" << makeQuoted( name ) << " - not found\n";
		}
		else
		{
			m_module->capture();
			if ( !globalModuleServer().getError() ) {
				m_table = static_cast<Type*>( m_module->getTable() );
			}
		}
	}
}
~ModuleRef(){
	if ( m_module != 0 ) {
		m_module->release();
	}
}
Type* getTable(){
#if GDEF_DEBUG
	ASSERT_MESSAGE( m_table != 0, "ModuleRef::getTable: type=" << makeQuoted( typename Type::Name() ) << " version=" << makeQuoted( typename Type::Version() ) << " - module-reference used without being initialised" );
#endif
	return m_table;
}
};

template<typename Type>
class SingletonModuleRef
{
Module* m_module;
Type* m_table;
public:

SingletonModuleRef()
	: m_module( 0 ), m_table( 0 ){
}

bool initialised() const {
	return m_module != 0;
}

void initialise( const char* name ){
	m_module = globalModuleServer().findModule( typename Type::Name(), typename Type::Version(), name );
	if ( m_module == 0 ) {
		globalModuleServer().setError( true );
		globalErrorStream() << "SingletonModuleRef::initialise: type=" << makeQuoted( typename Type::Name() ) << " version=" << makeQuoted( typename Type::Version() ) << " name=" << makeQuoted( name ) << " - not found\n";
	}
}

Type* getTable(){
#if GDEF_DEBUG
	ASSERT_MESSAGE( m_table != 0, "SingletonModuleRef::getTable: type=" << makeQuoted( typename Type::Name() ) << " version=" << makeQuoted( typename Type::Version() ) << " - module-reference used without being initialised" );
#endif
	return m_table;
}
void capture(){
	if ( initialised() ) {
		m_module->capture();
		m_table = static_cast<Type*>( m_module->getTable() );
	}
}
void release(){
	if ( initialised() ) {
		m_module->release();
	}
}
};

template<typename Type>
class GlobalModule
{
static SingletonModuleRef<Type> m_instance;
public:
static SingletonModuleRef<Type>& instance(){
	return m_instance;
}
static Type& getTable(){
	return *m_instance.getTable();
}
};

template<class Type>
SingletonModuleRef<Type> GlobalModule<Type>::m_instance;


template<typename Type>
class GlobalModuleRef
{
public:
GlobalModuleRef( const char* name = "*" ){
	if ( !globalModuleServer().getError() ) {
		GlobalModule<Type>::instance().initialise( name );
	}
	GlobalModule<Type>::instance().capture();
}
~GlobalModuleRef(){
	GlobalModule<Type>::instance().release();
}
Type& getTable(){
	return GlobalModule<Type>::getTable();
}
};

#endif