anchor.diff:      true;
   is_user_root_dir_uuid(FileUuid) ->
       case FileUuid of
  -        <<"userRoot", "_", _UserId/binary>> ->
  +        <<?USER_ROOT_PREFIX, _UserId/binary>> ->
               true;
           _ ->
               false
  
positive.code: %%--------------------------------------------------------------------
  -spec user_root_dir_uuid(UserId :: od_user:id()) -> file_meta:uuid().
  user_root_dir_uuid(UserId) ->
      <<"userRoot", "_", UserId/binary>>.
  
  %%--------------------------------------------------------------------
  %% @doc Returns Uuid of user's root directory.
  
negative.code: -spec unpack_share_guid(od_share:share_guid()) ->
      {file_meta:uuid(), undefined | od_space:id(), od_share:id() | undefined}.
  unpack_share_guid(ShareGuid) ->
      try binary:split(ShareGuid, <<?GUID_SEPARATOR>>, [global]) of
          [<<?SHARE_GUID_PREFIX>>, FileUuid, <<>>, ShareId] ->
              {FileUuid, undefined, ShareId};
          [<<?SHARE_GUID_PREFIX>>, FileUuid, SpaceId, ShareId] ->
              {FileUuid, SpaceId, ShareId};
          [<<?GUID_PREFIX>>, FileUuid, <<>>] ->
              {FileUuid, undefined, undefined};
          [<<?GUID_PREFIX>>, FileUuid, SpaceId] ->
              {FileUuid, SpaceId, undefined};
          _ ->
              {ShareGuid, undefined, undefined}
  