def download_file(url, dest=None, chunk_size=1024, replace="ask",
                  label="Downloading {dest_basename} ({size:.2f}MB)",
                  expected_extension=None):
    """Download a file from a given URL and display progress.

    :param dest: If the destination exists and is a directory, the filename
        will be guessed from the Content-Disposition header. If the destination
        is an existing file, the user will either be prompted to overwrite, or
        the file will be replaced (depending on the value of **replace**). If
        the destination does not exist, it will be used as the filename.
    :param int chunk_size: bytes read in at a time.
    :param replace: If `False`, an existing destination file will not be
        overwritten.
    :param label: a string which is formatted and displayed as the progress bar
        label. Variables provided include *dest_basename*, *dest*, and *size*.
    :param expected_extension: if set, the filename will be sanitized to ensure
        it has the given extension. The extension should not start with a dot
        (`.`).
    """
    dest = Path(dest or url.split("/")[-1])
    response = get(url, stream=True)
    if (dest.exists()
            and dest.is_dir()
            and "Content-Disposition" in response.headers):
        content_disposition = rfc6266.parse_requests_response(response)
        if expected_extension is not None:
            filename = content_disposition.filename_sanitized(
                expected_extension)
        filename = secure_filename(filename)
        dest = dest / filename
    if dest.exists() and not dest.is_dir():
        if (replace is False
                or replace == "ask"
                and not click.confirm("Replace {}?".format(dest))):
            return str(dest)
    size = int(response.headers.get("content-length", 0))
    label = label.format(dest=dest, dest_basename=dest.name,
                         size=size/1024.0/1024)
    with click.open_file(str(dest), "wb") as f:
        content_iter = response.iter_content(chunk_size=chunk_size)
        with click.progressbar(content_iter, length=size/1024,
                               label=label) as bar:
            for chunk in bar:
                if chunk:
                    f.write(chunk)
                    f.flush()
    return str(dest)
def AddResultsOptions(parser):
  group = optparse.OptionGroup(parser, 'Results options')
  group.add_option('--chartjson', action='store_true',
                   help='Output Chart JSON. Ignores --output-format.')
  group.add_option('--output-format', action='append', dest='output_formats',
                    choices=_OUTPUT_FORMAT_CHOICES, default=[],
                    help='Output format. Defaults to "%%default". '
                    'Can be %s.' % ', '.join(_OUTPUT_FORMAT_CHOICES))
  group.add_option('-o', '--output',
                    dest='output_file',
                    default=None,
                    help='Redirects output to a file. Defaults to stdout.')
  group.add_option('--output-dir', default=util.GetBaseDir(),
                    help='Where to save output data after the run.')
  group.add_option('--output-trace-tag',
                    default='',
                    help='Append a tag to the key of each result trace. Use '
                    'with html, buildbot, csv-pivot-table output formats.')
  group.add_option('--reset-results', action='store_true',
                    help='Delete all stored results.')
  group.add_option('--upload-results', action='store_true',
                    help='Upload the results to cloud storage.')
  group.add_option('--upload-bucket', default='internal',
                    choices=['public', 'partner', 'internal'],
                    help='Storage bucket to use for the uploaded results. '
                    'Defaults to internal. Supported values are: '
                    'public, partner, internal')
  group.add_option('--results-label',
                    default=None,
                    help='Optional label to use for the results of a run .')
  group.add_option('--suppress_gtest_report',
                   default=False,
                   help='Whether to suppress GTest progress report.')
  parser.add_option_group(group)