anchor.diff:  -spec handle_fuse_message(ProtocolVersion :: term(), Record :: tuple(), FuseID :: string()) -> Result when
     Result :: term().
   %% ====================================================================
  -
  -%% TODO zastanowić się nad formą odpowiedzi o niesistniejący plik (teraz zwraca błąd)
  +%% TODO sprawdzić czy poprawnie odpowiada na zapytanie o nieistniejacy plik
   handle_fuse_message(ProtocolVersion, Record, FuseID) when is_record(Record, getfilelocation) ->
     File = Record#getfilelocation.file_logic_name,
  -
  -  Pid = self(),
  -  Ans = gen_server:call(?Dispatcher_Name, {dao, ProtocolVersion, Pid, 1, {vfs, get_file, [File]}}),
  -  {Status, TmpAns} = wait_for_dao_ans(Ans, File, 1, "get_file"),
  +  {Status, TmpAns} = get_file(ProtocolVersion, File, FuseID),
   
     Validity = ?LOCATION_VALIDITY,
     case Status of
  
positive.code:   Result :: term().
  %% ====================================================================
  
  save_file_descriptor(ProtocolVersion, File, FuseID, Validity) ->
    Pid = self(),
  
    {Megaseconds,Seconds, _Microseconds} = os:timestamp(),
    Time = 1000000*Megaseconds + Seconds,
    Descriptor = #file_descriptor{file = File, fuse_id = FuseID, create_time = Time, expire_time = Validity},
  
    Ans = gen_server:call(?Dispatcher_Name, {dao, ProtocolVersion, Pid, 100, {vfs, save_descriptor, [Descriptor]}}),
    wait_for_dao_ans(Ans, File, 100, "save_descriptor").
  
  %% wait_for_dao_ans/4
  %% ====================================================================
  
negative.code: -include("communication_protocol_pb.hrl").
  
  -define(LOCATION_VALIDITY, 60*15).
  -define(FILE_NOT_FOUND_MESSAGE, "Error: file_not_found").
  -define(FILE_ALREADY_EXISTS, "Error: file_already_exists").
  
  %% TODO zrobić okresowe sprawdzanie drskryptorów i usuwanie przestarzałych z bazy
  %% potrzebna w dao funkcja listująca wszystkie deskryptory
  %% TODO dodać wszędzie logowanie w przypadku błędów
  
  %% ====================================================================
  %% API functions
  