anchor.diff:  %%--------------------------------------------------------------------
   -spec spaceid_to_space_dir_uuid(od_space:id()) -> file_meta:uuid().
   spaceid_to_space_dir_uuid(SpaceId) ->
  -    <<"space", "_", SpaceId/binary>>.
  +    <<?SPACE_ROOT_PREFIX, SpaceId/binary>>.
   
   %%--------------------------------------------------------------------
   %% @doc Convert SpaceId to guid of file_meta document of this space directory.
  
positive.code: -export([guid_to_share_guid/2, share_guid_to_guid/1, is_share_guid/1,
      guid_to_share_id/1, guid_to_space_id/1]).
  
  %%%===================================================================
  %%% API
  %%%===================================================================
  
negative.code: -spec space_dir_uuid_to_spaceid_no_error(file_meta:uuid()) -> od_space:id().
  space_dir_uuid_to_spaceid_no_error(SpaceUuid) ->
      case SpaceUuid of
          <<?SPACE_ROOT_PREFIX, SpaceId/binary>> ->
              SpaceId;
          _ ->
              <<>>
  