1 files changed, 32 insertions, 28 deletions
diff --git a/synapse/handlers/room_member.py b/synapse/handlers/room_member.py
index 8c41cb6f3c..b69f36aefe 100644
--- a/synapse/handlers/room_member.py
+++ b/synapse/handlers/room_member.py
@@ -23,7 +23,8 @@ from synapse.api.constants import (
     EventTypes, Membership,
 )
 from synapse.api.errors import AuthError, SynapseError, Codes
-from synapse.util.logcontext import preserve_context_over_fn
+from synapse.util.async import Linearizer
+from synapse.util.distributor import user_left_room, user_joined_room
 
 from signedjson.sign import verify_signed_json
 from signedjson.key import decode_verify_key_bytes
@@ -37,20 +38,6 @@ logger = logging.getLogger(__name__)
 id_server_scheme = "https://"
 
 
-def user_left_room(distributor, user, room_id):
-    return preserve_context_over_fn(
-        distributor.fire,
-        "user_left_room", user=user, room_id=room_id
-    )
-
-
-def user_joined_room(distributor, user, room_id):
-    return preserve_context_over_fn(
-        distributor.fire,
-        "user_joined_room", user=user, room_id=room_id
-    )
-
-
 class RoomMemberHandler(BaseHandler):
     # TODO(paul): This handler currently contains a messy conflation of
     #   low-level API that works on UserID objects and so on, and REST-level
@@ -60,6 +47,8 @@ class RoomMemberHandler(BaseHandler):
     def __init__(self, hs):
         super(RoomMemberHandler, self).__init__(hs)
 
+        self.member_linearizer = Linearizer()
+
         self.clock = hs.get_clock()
 
         self.distributor = hs.get_distributor()
@@ -183,6 +172,34 @@ class RoomMemberHandler(BaseHandler):
             third_party_signed=None,
             ratelimit=True,
     ):
+        key = (target, room_id,)
+
+        with (yield self.member_linearizer.queue(key)):
+            result = yield self._update_membership(
+                requester,
+                target,
+                room_id,
+                action,
+                txn_id=txn_id,
+                remote_room_hosts=remote_room_hosts,
+                third_party_signed=third_party_signed,
+                ratelimit=ratelimit,
+            )
+
+        defer.returnValue(result)
+
+    @defer.inlineCallbacks
+    def _update_membership(
+            self,
+            requester,
+            target,
+            room_id,
+            action,
+            txn_id=None,
+            remote_room_hosts=None,
+            third_party_signed=None,
+            ratelimit=True,
+    ):
         effective_membership_state = action
         if action in ["kick", "unban"]:
             effective_membership_state = "leave"
@@ -375,19 +392,6 @@ class RoomMemberHandler(BaseHandler):
             and guest_access.content["guest_access"] == "can_join"
         )
 
-    def _should_do_dance(self, current_state, inviter, room_hosts=None):
-        # TODO: Shouldn't this be remote_room_host?
-        room_hosts = room_hosts or []
-
-        is_host_in_room = self.is_host_in_room(current_state)
-        if is_host_in_room:
-            return False, room_hosts
-
-        if inviter and not self.hs.is_mine(inviter):
-            room_hosts.append(inviter.domain)
-
-        return True, room_hosts
-
     @defer.inlineCallbacks
     def lookup_room_alias(self, room_alias):
         """