neighbor/upnp: roll back changes if DoOpen() fails

src/neighbor/plugins/UdisksNeighborPlugin.cxx

@@ -113,15 +113,19 @@ UdisksNeighborExplorer::DoOpen()
 
 	auto &connection = GetConnection();
 
+	/* this ugly try/catch cascade is only here because this
+	   method has no RAII for this method - TODO: improve this */
 	try {
 		Error error;
 		dbus_bus_add_match(connection, udisks_neighbor_match, error);
 		error.CheckThrow("DBus AddMatch error");
 
+		try {
 			dbus_connection_add_filter(connection,
 						   HandleMessage, this,
 						   nullptr);
 
+			try {
 				auto msg = Message::NewMethodCall(UDISKS2_INTERFACE,
 								  UDISKS2_PATH,
 								  DBUS_OM_INTERFACE,
@@ -130,6 +134,17 @@ UdisksNeighborExplorer::DoOpen()
 						  std::bind(&UdisksNeighborExplorer::OnListNotify,
 							    this, std::placeholders::_1));
 			} catch (...) {
+				dbus_connection_remove_filter(connection,
+							      HandleMessage,
+							      this);
+				throw;
+			}
+		} catch (...) {
+			dbus_bus_remove_match(connection,
+					      udisks_neighbor_match, nullptr);
+			throw;
+		}
+	} catch (...) {
 		dbus_glue.Destruct();
 		throw;
 	}