code: def ParseFileObject(self, parser_mediator, file_object):
      
      filename = parser_mediator.GetFilename()
  
      if (not self._CACHE_FILENAME_RE.match(filename) and
          not filename.startswith('_CACHE_00')):
        raise errors.UnableToParseFile('Not a Firefox cache1 file.')
  
      display_name = parser_mediator.GetDisplayName()
      firefox_config = self._GetFirefoxConfig(file_object, display_name)
  
      file_object.seek(firefox_config.first_record_offset)
  
      while file_object.get_offset() < file_object.get_size():
        try:
          self._ParseCacheEntry(
              parser_mediator, file_object, display_name,
              firefox_config.block_size)
  
        except IOError:
          file_offset = file_object.get_offset() - self._MINIMUM_BLOCK_SIZE
          logger.debug((
              '[{0:s}] Invalid cache record in file: {1:s} at offset: '
              '{2:d}.').format(self.NAME, display_name, file_offset))
docs: Parses a Firefox cache file-like object.
  
      Args:
        parser_mediator (ParserMediator): mediates interactions between parsers
            and other components, such as storage and dfvfs.
        file_object (dfvfs.FileIO): a file-like object.
  
      Raises:
        UnableToParseFile: when the file cannot be parsed.