private function fetchAllFilesUnderGit()
  {
    $command = "git ls-files";
    exec($command, $output, $return);
    if ($return!=0) $this->logError("Can not execute command %s in exec", $command);

    foreach ($output as $filename)
    {
      $this->myLastCommitTimes[$filename] = 0;
    }
  }