anchor.diff:      Local = filename:join(Root, Path),
       {ok, Local, Url}.
   
  +-spec safe_rename(string(), string()) -> 'ok' | {'error', 'file_exists' | {'chmod_failed', _} | {'rename_failed', _}}.
   safe_rename(Src, Dst) ->
       case prim_file:read_file_info(Dst) of
           {error, enoent} ->
  
positive.code: replace([C|R], A, B, L) ->
      replace(R, A, B, [C|L]).
  
  startswith(B, Prefix) when size(B) < size(Prefix) ->
      false;
  startswith(B, Prefix) ->
      {Head, _} = split_binary(B, size(Prefix)),
      Head =:= Prefix.
  
  timestamp() -> timestamp(now()).
  timestamp({X0, X1, X2}) ->
      io_lib:format("~.16b-~.16b-~.16b", [X0, X1, X2]).
  
  
negative.code:             {error, invalid_output}
      end.
  
  -spec fold_files(string(), fun((string(), string(), T) -> T), T) -> T.
  fold_files(Dir, Fun, Acc0) ->
      {ok, L} = prim_file:list_dir(Dir),
      lists:foldl(fun(F, Acc) ->
  