1 files changed, 73 insertions, 5 deletions

diff --git a/libs/pbd/pbd/shiva.h b/libs/pbd/pbd/shiva.h
index 5110f48332..53b613ea2b 100644
--- a/libs/pbd/pbd/shiva.h
+++ b/libs/pbd/pbd/shiva.h
@@ -5,28 +5,96 @@
 
 namespace PBD {
 
-template<typename ObjectWithGoingAway, typename ObjectToBeDestroyed>
-
 /* 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 */
 
-		_connection1 = emitter.GoingAway.connect 
+		_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, &Shiva<ObjectWithGoingAway,ObjectToBeDestroyed>::forget));
+			(sigc::mem_fun (*this, &PairedShiva<ObjectWithGoingAway,ObjectToBeDestroyed>::forget));
 	}
 
-	~Shiva() { 
+	~PairedShiva() { 
 		forget ();
 	}