text: # -*- coding: utf-8 -*-
  # Copyright 2016 OpenMarket Ltd
  #
  # Licensed under the Apache License, Version 2.0 (the "License");
  # you may not use this file except in compliance with the License.
  # You may obtain a copy of the License at
  #
  #     http://www.apache.org/licenses/LICENSE-2.0
  #
  # Unless required by applicable law or agreed to in writing, software
  # distributed under the License is distributed on an "AS IS" BASIS,
  # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  # See the License for the specific language governing permissions and
  # limitations under the License.
  
  from synapse.storage import DataStore
  from synapse.util.caches.stream_change_cache import StreamChangeCache
  
  from ._base import BaseSlavedStore
  from ._slaved_id_tracker import SlavedIdTracker
  
  
  class SlavedGroupServerStore(BaseSlavedStore):
      def __init__(self, db_conn, hs):
          super(SlavedGroupServerStore, self).__init__(db_conn, hs)
  
          self.hs = hs
  
          self._group_updates_id_gen = SlavedIdTracker(
              db_conn, "local_group_updates", "stream_id",
          )
          self._group_updates_stream_cache = StreamChangeCache(
              "_group_updates_stream_cache", self._group_updates_id_gen.get_current_token(),
          )
  
      get_groups_changes_for_user = DataStore.get_groups_changes_for_user.__func__
      get_group_stream_token = DataStore.get_group_stream_token.__func__
      get_all_groups_for_user = DataStore.get_all_groups_for_user.__func__
  
      def stream_positions(self):
          result = super(SlavedGroupServerStore, self).stream_positions()
          result["groups"] = self._group_updates_id_gen.get_current_token()
          return result
  
      def process_replication_rows(self, stream_name, token, rows):
          if stream_name == "groups":
              self._group_updates_id_gen.advance(token)
              for row in rows:
                  self._group_updates_stream_cache.entity_has_changed(
                      row.user_id, token
                  )
  
          return super(SlavedGroupServerStore, self).process_replication_rows(
              stream_name, token, rows
          )
  