mtime = file_utils.get_file_raw_mtime(filename)
if self.mtime_by_filename.get(filename, 0) != mtime:
md5 = file_utils.get_file_md5(filename)
mtime = file_utils.get_file_raw_mtime(filename)
if self.mtime_by_filename.get(filename, 0) != mtime:
md5 = file_utils.get_file_md5(filename)