Start making more things use EventContext rather than event.*

synapse/state.py

@@ -135,6 +135,39 @@ class StateHandler(object):
 
         defer.returnValue(res[1].values())
 
+    @defer.inlineCallbacks
+    def annotate_context_with_state(self, event, context):
+        if event.is_state():
+            ret = yield self.resolve_state_groups(
+                [e for e, _ in event.prev_events],
+                event_type=event.event_type,
+                state_key=event.state_key,
+            )
+        else:
+            ret = yield self.resolve_state_groups(
+                [e for e, _ in event.prev_events],
+            )
+
+        group, curr_state, prev_state = ret
+
+        context.current_state = curr_state
+
+        prev_state = yield self.store.add_event_hashes(
+            prev_state
+        )
+
+        if hasattr(event, "auth_events") and event.auth_events:
+            auth_ids = zip(*event.auth_events)[0]
+            context.auth_events = {
+                k: v
+                for k, v in context.current_state.items()
+                if v.event_id in auth_ids
+            }
+
+        defer.returnValue(
+            (group, prev_state)
+        )
+
     @defer.inlineCallbacks
     @log_function
     def resolve_state_groups(self, event_ids, event_type=None, state_key=""):