From a5ba01eb76b02af6633598a4c2458b44ba6220b9 Mon Sep 17 00:00:00 2001
From: Will Hunt <willh@matrix.org>
Date: Tue, 5 Jan 2021 10:52:12 +0000
Subject: [PATCH] Fix complexity

---
 appservice/consumers/roomserver.go | 53 +++++++++++++++++-------------
 1 file changed, 30 insertions(+), 23 deletions(-)

diff --git a/appservice/consumers/roomserver.go b/appservice/consumers/roomserver.go
index f7d337457..5476d6ecc 100644
--- a/appservice/consumers/roomserver.go
+++ b/appservice/consumers/roomserver.go
@@ -123,6 +123,35 @@ func (s *OutputRoomEventConsumer) filterRoomserverEvents(
 	return nil
 }
 
+// appserviceHasMembershipInRoom returns a boolean depending on whether a given
+// appservice has membership at the time a given event was created.
+func (s *OutputRoomEventConsumer) appserviceHasMembershipForEvent(ctx context.Context, event *gomatrixserverlib.HeaderedEvent, appservice config.ApplicationService) bool {
+	// Check if any of the members in the room match the appservice
+	membershipReq := api.QueryStateAfterEventsRequest{
+		PrevEventIDs: []string{event.EventID()},
+		RoomID:       event.RoomID(),
+	}
+	var membershipRes api.QueryStateAfterEventsResponse
+
+	// XXX: This could potentially race if the state for the event is not known yet
+	// e.g. the event came over federation but we do not have the full state persisted.
+	if err := s.rsAPI.QueryStateAfterEvents(ctx, &membershipReq, &membershipRes); err == nil {
+		for _, ev := range membershipRes.StateEvents {
+			if ev.Type() == gomatrixserverlib.MRoomMember {
+				var membership, _ = ev.Membership()
+				if membership == gomatrixserverlib.Join && appservice.IsInterestedInUserID(*ev.StateKey()) {
+					return true
+				}
+			}
+		}
+	} else {
+		log.WithFields(log.Fields{
+			"room_id": event.RoomID(),
+		}).WithError(err).Errorf("Unable to get membership for room")
+	}
+	return false
+}
+
 // appserviceIsInterestedInEvent returns a boolean depending on whether a given
 // event falls within one of a given application service's namespaces.
 //
@@ -162,27 +191,5 @@ func (s *OutputRoomEventConsumer) appserviceIsInterestedInEvent(ctx context.Cont
 	}
 
 	// Check if any of the members in the room match the appservice
-	membershipReq := api.QueryStateAfterEventsRequest{
-		PrevEventIDs: []string{event.EventID()},
-		RoomID:       event.RoomID(),
-	}
-	var membershipRes api.QueryStateAfterEventsResponse
-
-	// XXX: This could potentially race if the state for the event is not known yet
-	// e.g. the event came over federation but we do not have the full state persisted.
-	if err := s.rsAPI.QueryStateAfterEvents(ctx, &membershipReq, &membershipRes); err == nil {
-		for _, ev := range membershipRes.StateEvents {
-			if ev.Type() == gomatrixserverlib.MRoomMember {
-				var membership, _ = ev.Membership()
-				if membership == gomatrixserverlib.Join && appservice.IsInterestedInUserID(*ev.StateKey()) {
-					return true
-				}
-			}
-		}
-	} else {
-		log.WithFields(log.Fields{
-			"room_id": event.RoomID(),
-		}).WithError(err).Errorf("Unable to get membership for room")
-	}
-	return false
+	return s.appserviceHasMembershipForEvent(ctx, event, appservice)
 }