Move updating the serial and state of the presence cache into a single function

synapse/handlers/presence.py

@@ -308,6 +308,11 @@ class PresenceHandler(BaseHandler):
         rm_handler = self.homeserver.get_handlers().room_member_handler
         return rm_handler.get_joined_rooms_for_user(user)
 
+    def get_joined_users_for_room_id(self, room_id):
+        rm_handler = self.homeserver.get_handlers().room_member_handler
+        return rm_handler.get_room_members(room_id)
+
+    @defer.inlineCallbacks
     def changed_presencelike_data(self, user, state):
         """Updates the presence state of a local user.
 
@@ -317,12 +322,9 @@ class PresenceHandler(BaseHandler):
         Returns:
             A Deferred
         """
-        statuscache = self._get_or_make_usercache(user)
-
         self._user_cachemap_latest_serial += 1
-        statuscache.update(state, serial=self._user_cachemap_latest_serial)
-
-        return self.push_presence(user, statuscache=statuscache)
+        statuscache = yield self.update_presence_cache(user, state)
+        yield self.push_presence(user, statuscache=statuscache)
 
     @log_function
     def started_user_eventstream(self, user):
@@ -345,13 +347,12 @@ class PresenceHandler(BaseHandler):
             room_id(str): The room id the user joined.
         """
         if self.hs.is_mine(user):
-            statuscache = self._get_or_make_usercache(user)
-
             # No actual update but we need to bump the serial anyway for the
             # event source
             self._user_cachemap_latest_serial += 1
-            statuscache.update({}, serial=self._user_cachemap_latest_serial)
-
+            statuscache = yield self.update_presence_cache(
+                user, room_ids=[room_id]
+            )
             self.push_update_to_local_and_remote(
                 observed_user=user,
                 room_ids=[room_id],
@@ -359,16 +360,17 @@ class PresenceHandler(BaseHandler):
             )
 
         # We also want to tell them about current presence of people.
-        rm_handler = self.homeserver.get_handlers().room_member_handler
-        curr_users = yield rm_handler.get_room_members(room_id)
+        curr_users = yield self.get_joined_users_for_room_id(room_id)
 
         for local_user in [c for c in curr_users if self.hs.is_mine(c)]:
-            statuscache = self._get_or_offline_usercache(local_user)
-            statuscache.update({}, serial=self._user_cachemap_latest_serial)
+            statuscache = yield self.update_presence_cache(
+                local_user, room_ids=[room_id], add_to_cache=False
+            )
+
             self.push_update_to_local_and_remote(
                 observed_user=local_user,
                 users_to_push=[user],
-                statuscache=self._get_or_offline_usercache(local_user),
+                statuscache=statuscache,
             )
 
     @defer.inlineCallbacks
@@ -829,10 +831,8 @@ class PresenceHandler(BaseHandler):
                     self.clock.time_msec() - state.pop("last_active_ago")
                 )
 
-            statuscache = self._get_or_make_usercache(user)
-
             self._user_cachemap_latest_serial += 1
-            statuscache.update(state, serial=self._user_cachemap_latest_serial)
+            yield self.update_presence_cache(user, state, room_ids=room_ids)
 
             if not observers and not room_ids:
                 logger.debug(" | no interested observers or room IDs")
@@ -890,6 +890,32 @@ class PresenceHandler(BaseHandler):
 
         yield defer.DeferredList(deferreds, consumeErrors=True)
 
+    @defer.inlineCallbacks
+    def update_presence_cache(self, user, state={}, room_ids=None,
+                              add_to_cache=True):
+        """Update the presence cache for a user with a new state and bump the
+        serial to the latest value.
+
+        Args:
+            user(UserID): The user being updated
+            state(dict): The presence state being updated
+            room_ids(None or list of str): A list of room_ids to update. If
+                room_ids is None then fetch the list of room_ids the user is
+                joined to.
+            add_to_cache: Whether to add an entry to the presence cache if the
+                user isn't already in the cache.
+        Returns:
+            A Deferred UserPresenceCache for the user being updated.
+        """
+        if room_ids is None:
+            room_ids = yield self.get_joined_rooms_for_user(user)
+        if add_to_cache:
+            statuscache = self._get_or_make_usercache(user)
+        else:
+            statuscache = self._get_or_offline_usercache(user)
+        statuscache.update(state, serial=self._user_cachemap_latest_serial)
+        defer.returnValue(statuscache)
+
     @defer.inlineCallbacks
     def push_update_to_local_and_remote(self, observed_user, statuscache,
                                         users_to_push=[], room_ids=[],