protofsm: add returned error for MsgEndpoint methods

protofsm/msg_router.go

@@ -47,11 +47,11 @@ type MsgEndpoint interface {
 
 	// CanHandle returns true if the target message can be routed to this
 	// endpoint.
-	CanHandle(msg PeerMsg) bool
+	CanHandle(msg PeerMsg) (bool, error)
 
 	// SendMessage handles the target message, and returns true if the
 	// message was able being processed.
-	SendMessage(msg PeerMsg) bool
+	SendMessage(msg PeerMsg) (bool, error)
 }
 
 // MsgRouter is an interface that represents a message router, which is generic
@@ -274,12 +274,20 @@ func (p *MultiMsgRouter) msgRouter() {
 			// to those that can handle it the message.
 			var couldSend bool
 			for _, endpoint := range endpoints {
-				if endpoint.CanHandle(msg) {
+				canHandle, err := endpoint.CanHandle(msg)
+				if err != nil {
+					msgQuery.SendError(err)
+				}
+
+				if canHandle {
 					log.Debugf("MsgRouter: sending msg %T "+
 						"to endpoint %s", msg.Message,
 						endpoint.Name())
 
-					sent := endpoint.SendMessage(msg)
+					sent, err := endpoint.SendMessage(msg)
+					if err != nil {
+						msgQuery.SendError(err)
+					}
 					couldSend = couldSend || sent
 				}
 			}

protofsm/msg_router_test.go

@@ -18,16 +18,16 @@ func (m *mockEndpoint) Name() string {
 	return args.String(0)
 }
 
-func (m *mockEndpoint) CanHandle(msg PeerMsg) bool {
+func (m *mockEndpoint) CanHandle(msg PeerMsg) (bool, error) {
 	args := m.Called(msg)
 
-	return args.Bool(0)
+	return args.Bool(0), nil
 }
 
-func (m *mockEndpoint) SendMessage(msg PeerMsg) bool {
+func (m *mockEndpoint) SendMessage(msg PeerMsg) (bool, error) {
 	args := m.Called(msg)
 
-	return args.Bool(0)
+	return args.Bool(0), nil
 }
 
 // TestMessageRouterOperation tests the basic operation of the message router: