1 files changed, 48 insertions, 6 deletions
diff --git a/synapse/handlers/federation.py b/synapse/handlers/federation.py
index 8e61d74b13..dc90a5dde4 100644
--- a/synapse/handlers/federation.py
+++ b/synapse/handlers/federation.py
@@ -101,6 +101,9 @@ class FederationHandler(BaseHandler):
     def on_receive_pdu(self, origin, pdu, state=None, auth_chain=None):
         """ Called by the ReplicationLayer when we have a new pdu. We need to
         do auth checks and put it through the StateHandler.
+
+        auth_chain and state are None if we already have the necessary state
+        and prev_events in the db
         """
         event = pdu
 
@@ -118,12 +121,21 @@ class FederationHandler(BaseHandler):
 
         # FIXME (erikj): Awful hack to make the case where we are not currently
         # in the room work
-        is_in_room = yield self.auth.check_host_in_room(
-            event.room_id,
-            self.server_name
-        )
-        if not is_in_room and not event.internal_metadata.is_outlier():
-            logger.debug("Got event for room we're not in.")
+        # If state and auth_chain are None, then we don't need to do this check
+        # as we already know we have enough state in the DB to handle this
+        # event.
+        if state and auth_chain and not event.internal_metadata.is_outlier():
+            is_in_room = yield self.auth.check_host_in_room(
+                event.room_id,
+                self.server_name
+            )
+        else:
+            is_in_room = True
+        if not is_in_room:
+            logger.info(
+                "Got event for room we're not in: %r %r",
+                event.room_id, event.event_id
+            )
 
             try:
                 event_stream_id, max_stream_id = yield self._persist_auth_tree(
@@ -1062,6 +1074,8 @@ class FederationHandler(BaseHandler):
 
     @defer.inlineCallbacks
     def get_state_for_pdu(self, room_id, event_id):
+        """Returns the state at the event. i.e. not including said event.
+        """
         yield run_on_reactor()
 
         state_groups = yield self.store.get_state_groups(
@@ -1103,6 +1117,34 @@ class FederationHandler(BaseHandler):
             defer.returnValue([])
 
     @defer.inlineCallbacks
+    def get_state_ids_for_pdu(self, room_id, event_id):
+        """Returns the state at the event. i.e. not including said event.
+        """
+        yield run_on_reactor()
+
+        state_groups = yield self.store.get_state_groups_ids(
+            room_id, [event_id]
+        )
+
+        if state_groups:
+            _, state = state_groups.items().pop()
+            results = state
+
+            event = yield self.store.get_event(event_id)
+            if event and event.is_state():
+                # Get previous state
+                if "replaces_state" in event.unsigned:
+                    prev_id = event.unsigned["replaces_state"]
+                    if prev_id != event.event_id:
+                        results[(event.type, event.state_key)] = prev_id
+                else:
+                    del results[(event.type, event.state_key)]
+
+            defer.returnValue(results.values())
+        else:
+            defer.returnValue([])
+
+    @defer.inlineCallbacks
     @log_function
     def on_backfill_request(self, origin, room_id, pdu_list, limit):
         in_room = yield self.auth.check_host_in_room(room_id, origin)