anchor.diff:  %% Convert Guid and share id to share guid (allowing for guest read)
   %% @end
   %%--------------------------------------------------------------------
  --spec guid_to_share_guid(fslogic_worker:file_guid(), od_share:id()) ->
  -    od_share:share_guid().
  +-spec guid_to_share_guid(file_guid(), share_id()) ->
  +    share_root_file_guid().
   guid_to_share_guid(Guid, ShareId) ->
       {FileUuid, SpaceId} = unpack_guid(Guid),
       pack_share_guid(FileUuid, SpaceId, ShareId).
  
positive.code:     end.
  
  
  %%--------------------------------------------------------------------
  %% @doc
  %% Returns file's Uuid and its SpaceId for given file's Guid.
  %% @end
  %%--------------------------------------------------------------------
  -spec unpack_guid(FileGuid :: fslogic_worker:file_guid()) ->
      {file_meta:uuid(), od_space:id() | undefined}.
  unpack_guid(FileGuid) ->
      {FileUuid, SpaceId, _ShareId} = unpack_share_guid(FileGuid),
      {FileUuid, SpaceId}.
  
negative.code: %% For given file Uuid and spaceId generates file's Guid.
  %% @end
  %%--------------------------------------------------------------------
  -spec pack_guid(file_meta_uuid(), space_id() | undefined) -> file_guid().
  pack_guid(FileUuid, SpaceId) ->
      DefinedSpaceId = utils:ensure_defined(SpaceId, undefined, <<>>),
      http_utils:base64url_encode(<<?GUID_PREFIX, ?GUID_SEPARATOR,
  