diff --git a/synapse/storage/databases/main/user_directory.py b/synapse/storage/databases/main/user_directory.py
index c977db042e..f2f9a5799a 100644
--- a/synapse/storage/databases/main/user_directory.py
+++ b/synapse/storage/databases/main/user_directory.py
@@ -15,7 +15,7 @@
import logging
import re
-from typing import Any, Dict, Iterable, Optional, Tuple
+from typing import Any, Dict, Iterable, Optional, Set, Tuple
from synapse.api.constants import EventTypes, JoinRules
from synapse.storage.database import DatabasePool
@@ -675,6 +675,48 @@ class UserDirectoryStore(UserDirectoryBackgroundUpdateStore):
users.update(rows)
return list(users)
+ @cached()
+ async def get_shared_rooms_for_users(
+ self, user_id: str, other_user_id: str
+ ) -> Set[str]:
+ """
+ Returns the rooms that a local user shares with another local or remote user.
+
+ Args:
+ user_id: The MXID of a local user
+ other_user_id: The MXID of the other user
+
+ Returns:
+ A set of room ID's that the users share.
+ """
+
+ def _get_shared_rooms_for_users_txn(txn):
+ txn.execute(
+ """
+ SELECT p1.room_id
+ FROM users_in_public_rooms as p1
+ INNER JOIN users_in_public_rooms as p2
+ ON p1.room_id = p2.room_id
+ AND p1.user_id = ?
+ AND p2.user_id = ?
+ UNION
+ SELECT room_id
+ FROM users_who_share_private_rooms
+ WHERE
+ user_id = ?
+ AND other_user_id = ?
+ """,
+ (user_id, other_user_id, user_id, other_user_id),
+ )
+ rows = self.db_pool.cursor_to_dict(txn)
+ return rows
+
+ rows = await self.db_pool.runInteraction(
+ "get_shared_rooms_for_users", _get_shared_rooms_for_users_txn
+ )
+
+ return {row["room_id"] for row in rows}
+
async def get_user_directory_stream_pos(self) -> int:
return await self.db_pool.simple_select_one_onecol(
table="user_directory_stream_pos",
|
