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#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:
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:
ProxyShiva (ObjectWithGoingAway& emitter, ObjectToBeDestroyed& receiver, void (*callback)(ObjectToBeDestroyed*, ObjectWithGoingAway*)) {
/* if the emitter goes away, destroy the receiver */
_callback = callback;
_callback_argument1 = &receiver;
_callback_argument2 = &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*);
ObjectToBeDestroyed* _callback_argument1;
ObjectWithGoingAway* _callback_argument2;
void destroy (ObjectToBeDestroyed* obj) {
/* callback must destroy obj if appropriate, not done here */
_callback (obj, _callback_argument2);
forget ();
}
void forget () {
_connection.disconnect ();
}
};
template<typename ObjectWithGoingAway, typename ObjectToBeDestroyed>
class PairedShiva {
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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