Implement new replace_state and changed prev_state

`prev_state` is now a list of previous state ids, similiar to
prev_events. `replace_state` now points to what we think was replaced.

1 files changed, 69 insertions, 23 deletions

diff --git a/synapse/storage/__init__.py b/synapse/storage/__init__.py

index 6b8fed4502..2d62fc2ed0 100644
--- a/synapse/storage/__init__.py
+++ b/synapse/storage/__init__.py
@@ -242,8 +242,8 @@ class DataStore(RoomMemberStore, RoomStore,
                 "state_key": event.state_key,
             }
 
-            if hasattr(event, "prev_state"):
-                vals["prev_state"] = event.prev_state
+            if hasattr(event, "replaces_state"):
+                vals["prev_state"] = event.replaces_state
 
             self._simple_insert_txn(txn, "state_events", vals)
 
@@ -258,6 +258,40 @@ class DataStore(RoomMemberStore, RoomStore,
                 }
             )
 
+            for e_id, h in event.prev_state:
+                self._simple_insert_txn(
+                    txn,
+                    table="event_edges",
+                    values={
+                        "event_id": event.event_id,
+                        "prev_event_id": e_id,
+                        "room_id": event.room_id,
+                        "is_state": 1,
+                    },
+                    or_ignore=True,
+                )
+
+            if not backfilled:
+                self._simple_insert_txn(
+                    txn,
+                    table="state_forward_extremities",
+                    values={
+                        "event_id": event.event_id,
+                        "room_id": event.room_id,
+                        "type": event.type,
+                        "state_key": event.state_key,
+                    }
+                )
+
+                for prev_state_id, _ in event.prev_state:
+                    self._simple_delete_txn(
+                        txn,
+                        table="state_forward_extremities",
+                        keyvalues={
+                            "event_id": prev_state_id,
+                        }
+                    )
+
         for hash_alg, hash_base64 in event.hashes.items():
             hash_bytes = decode_base64(hash_base64)
             self._store_event_content_hash_txn(
@@ -357,7 +391,7 @@ class DataStore(RoomMemberStore, RoomStore,
             ],
         )
 
-    def snapshot_room(self, room_id, user_id, state_type=None, state_key=None):
+    def snapshot_room(self, event):
         """Snapshot the room for an update by a user
         Args:
             room_id (synapse.types.RoomId): The room to snapshot.
@@ -368,16 +402,29 @@ class DataStore(RoomMemberStore, RoomStore,
             synapse.storage.Snapshot: A snapshot of the state of the room.
         """
         def _snapshot(txn):
-            membership_state = self._get_room_member(txn, user_id, room_id)
-            prev_events = self._get_latest_events_in_room(txn, room_id)
+            prev_events = self._get_latest_events_in_room(
+                txn,
+                event.room_id
+            )
+
+            prev_state = None
+            state_key = None
+            if hasattr(event, "state_key"):
+                state_key = event.state_key
+                prev_state = self._get_latest_state_in_room(
+                    txn,
+                    event.room_id,
+                    type=event.type,
+                    state_key=state_key,
+                )
 
             return Snapshot(
                 store=self,
-                room_id=room_id,
-                user_id=user_id,
+                room_id=event.room_id,
+                user_id=event.user_id,
                 prev_events=prev_events,
-                membership_state=membership_state,
-                state_type=state_type,
+                prev_state=prev_state,
+                state_type=event.type,
                 state_key=state_key,
             )
 
@@ -400,30 +447,29 @@ class Snapshot(object):
     """
 
     def __init__(self, store, room_id, user_id, prev_events,
-                 membership_state, state_type=None, state_key=None,
-                 prev_state_pdu=None):
+                 prev_state, state_type=None, state_key=None):
         self.store = store
         self.room_id = room_id
         self.user_id = user_id
         self.prev_events = prev_events
-        self.membership_state = membership_state
+        self.prev_state = prev_state
         self.state_type = state_type
         self.state_key = state_key
-        self.prev_state_pdu = prev_state_pdu
 
     def fill_out_prev_events(self, event):
-        if hasattr(event, "prev_events"):
-            return
+        if not hasattr(event, "prev_events"):
+            event.prev_events = [
+                (event_id, hashes)
+                for event_id, hashes, _ in self.prev_events
+            ]
 
-        event.prev_events = [
-            (event_id, hashes)
-            for event_id, hashes, _ in self.prev_events
-        ]
+            if self.prev_events:
+                event.depth = max([int(v) for _, _, v in self.prev_events]) + 1
+            else:
+                event.depth = 0
 
-        if self.prev_events:
-            event.depth = max([int(v) for _, _, v in self.prev_events]) + 1
-        else:
-            event.depth = 0
+        if not hasattr(event, "prev_state") and self.prev_state is not None:
+            event.prev_state = self.prev_state
 
 
 def schema_path(schema):