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/*
* The Mana Server
* Copyright (C) 2007-2010 The Mana World Development Team
*
* This file is part of The Mana Server.
*
* The Mana Server 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
* any later version.
*
* The Mana Server 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 The Mana Server. If not, see <http://www.gnu.org/licenses/>.
*/
#ifndef GAMESERVER_EVENTLISTENER_H
#define GAMESERVER_EVENTLISTENER_H
class Thing;
class Being;
class Character;
struct EventDispatch;
/**
* Pointer to a dispatch table.
*/
struct EventListener
{
const EventDispatch *dispatch;
EventListener(const EventDispatch *d): dispatch(d) {}
};
/**
* Dispatch table for event notification.
*/
struct EventDispatch
{
/**
* Called just after something is inserted in a map.
*/
void (*inserted)(const EventListener *, Thing *);
/**
* Called just before something is removed from a map.
*/
void (*removed)(const EventListener *, Thing *);
/**
* Called just after a being has died.
*/
void (*died)(const EventListener *, Being *);
/**
* Called just before a character is deleted.
*/
void (*disconnected)(const EventListener *, Character *);
/**
* Initializes dispatch methods as missing.
*/
EventDispatch():
inserted(0), removed(0), died(0), disconnected(0)
{}
};
/**
* Helper for using member functions as dispatch methods. The 3-level structure
* is due to default template parameter not being allowed on functions yet.
* Conceptually, this helper takes two parameters: the name of the member
* variable pointing to the dispatch table and the name of the member function
* to call on dispatch. With these two parameters, it creates a dispatch
* method. When called, this free function forwards the call to the member
* function.
* Pseudo-syntax for getting a dispatch method:
* <code>&EventListenerFactory< _, DispatchPointerName >::create< _, MemberFunctionName >::function</code>
* See the start of the spawnarea.cpp file for a complete example.
*/
template< class T, EventListener T::*D >
struct EventListenerFactory
{
template< class U, void (T::*F)(U *), class V = U >
struct create
{
static void function(const EventListener *d, V *u)
{
/* Get the address of the T object by substracting the offset of D
from the pointer d. */
T *t = (T *)((char *)d -
((char *)&(((T *)42)->*D) - (char *)&(*(T *)42)));
// Then call the method F of this T object.
(t->*F)(u);
}
};
};
#endif
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