code: func (info *Info) UpvertedFiles() []FileInfo {
  	if len(info.Files) == 0 {
  		return []FileInfo{{
  			Length: info.Length,
  			// Callers should determine that Info.Name is the basename, and
  			// thus a regular file.
  			Path: nil,
  		}}
  	}
  	return info.Files
  }
docs: // The files field, converted up from the old single-file in the parent info
  // dict if necessary. This is a helper to avoid having to conditionally handle
  // single and multi-file torrent infos.