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/*
Copyright (C) 2000-2007 Paul Davis
This program 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.
This program 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 this program; if not, write to the Free Software
Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*/
#ifndef __pbd_shiva_h__
#define __pbd_shiva_h__
#include <sigc++/sigc++.h>
namespace PBD {
/* named after the Hindu god Shiva, The Destroyer */
template<typename ObjectWithGoingAway, typename ObjectToBeDestroyed>
class Shiva : public sigc::trackable
{
public:
Shiva (ObjectWithGoingAway& emitter, ObjectToBeDestroyed& receiver) {
/* if the emitter goes away, destroy the receiver */
_connection = emitter.GoingAway.connect
(sigc::bind (sigc::mem_fun
(*this, &Shiva<ObjectWithGoingAway,ObjectToBeDestroyed>::destroy),
&receiver));
}
~Shiva() {
forget ();
}
private:
sigc::connection _connection;
void destroy (ObjectToBeDestroyed* obj) {
delete obj;
forget ();
}
void forget () {
_connection.disconnect ();
}
};
template<typename ObjectWithGoingAway, typename ObjectToBeDestroyed>
class ProxyShiva : public sigc::trackable
{
public:
ProxyShiva (ObjectWithGoingAway& emitter, ObjectToBeDestroyed& receiver, void (*callback)(ObjectToBeDestroyed*, ObjectWithGoingAway*)) {
/* if the emitter goes away, destroy the receiver */
_callback = callback;
_callback_argument = &emitter;
_connection = emitter.GoingAway.connect
(sigc::bind (sigc::mem_fun
(*this, &ProxyShiva<ObjectWithGoingAway,ObjectToBeDestroyed>::destroy),
&receiver));
}
~ProxyShiva () {
forget ();
}
private:
sigc::connection _connection;
void (*_callback) (ObjectToBeDestroyed*, ObjectWithGoingAway*);
ObjectWithGoingAway* _callback_argument;
void destroy (ObjectToBeDestroyed* obj) {
/* callback must destroy obj if appropriate, not done here */
_callback (obj, _callback_argument);
forget ();
}
void forget () {
_connection.disconnect ();
}
};
template<typename ObjectWithGoingAway, typename ObjectToBeDestroyed>
class PairedShiva : public sigc::trackable
{
public:
PairedShiva (ObjectWithGoingAway& emitter, ObjectToBeDestroyed& receiver) {
/* if the emitter goes away, destroy the receiver */
_connection1 = emitter.GoingAway.connect
(sigc::bind (sigc::mem_fun
(*this, &PairedShiva<ObjectWithGoingAway,ObjectToBeDestroyed>::destroy),
&receiver));
/* if the receiver goes away, forget all this nonsense */
_connection2 = receiver.GoingAway.connect
(sigc::mem_fun (*this, &PairedShiva<ObjectWithGoingAway,ObjectToBeDestroyed>::forget));
}
~PairedShiva() {
forget ();
}
private:
sigc::connection _connection1;
sigc::connection _connection2;
void destroy (ObjectToBeDestroyed* obj) {
delete obj;
forget ();
}
void forget () {
_connection1.disconnect ();
_connection2.disconnect ();
}
};
}
#endif /* __pbd_shiva_h__ */
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