docs: @Nullable
    private DirectoryEntry getRealEntry(DirectoryEntry entry) {
      Name name = entry.name();
  
      if (name.equals(Name.SELF) || name.equals(Name.PARENT)) {
        Directory dir = toDirectory(entry.file());
        assert dir != null;
        return dir.entryInParent();
      } else {
        return entry;
      }
    }