tools/metrics/histograms/update_use_counter_css.py

#!/usr/bin/env python
# Copyright 2014 The Chromium Authors. All rights reserved.
# Use of this source code is governed by a BSD-style license that can be
# found in the LICENSE file.

"""Scans the Chromium source of UseCounter, formats the Feature enum for
histograms.xml and merges it. This script can also generate a python code
snippet to put in uma.py of Chromium Dashboard. Make sure that you review the
output for correctness.
"""

import optparse
import os
import re
import sys

sys.path.append(os.path.join(os.path.dirname(__file__), '..', 'common'))
import path_util

import update_histogram_enum
import update_use_counter_feature_enum


USE_COUNTER_CPP_PATH = 'third_party/blink/renderer/core/frame/use_counter.cc'


def EnumToCssProperty(enum_name):
  """Converts a camel cased enum name to the lower case CSS property."""
  # The first group also searches for uppercase letters to account for single
  # uppercase letters, such as in "ZIndex" that need to convert to "z-index".
  return re.sub(r'([a-zA-Z])([A-Z])', r'\1-\2', enum_name).lower()


def ReadCssProperties(filename):
  # Read the file as a list of lines
  with open(path_util.GetInputFile(filename)) as f:
    content = f.readlines()

  # Looking for a pair of lines like "case CSSPropertyGrid:\n return 453;".
  ENUM_REGEX = re.compile(r"""CSSProperty(.*):  # capture the enum name
                              \s*return\s*
                              ([0-9]+)          # capture the id
                              """, re.VERBOSE)

  properties = {}
  previous_line = ''
  for line in content:
    enum_match = ENUM_REGEX.search(previous_line + '\n' + line)
    if enum_match:
      enum_name = enum_match.group(1)
      property_id = int(enum_match.group(2))
      properties[property_id] = EnumToCssProperty(enum_name)
      previous_line = ''
    else:
      previous_line = line

  return properties


if __name__ == '__main__':
  parser = optparse.OptionParser()
  parser.add_option('--for-dashboard', action='store_true', dest='dashboard',
                    default=False,
                    help='Print enum definition formatted for use in uma.py of '
                    'Chromium dashboard developed at '
                    'https://github.com/GoogleChrome/chromium-dashboard')
  options, args = parser.parse_args()

  if options.dashboard:
    enum_dict = ReadCssProperties(USE_COUNTER_CPP_PATH)
    update_use_counter_feature_enum.PrintEnumForDashboard(enum_dict)
  else:
    update_histogram_enum.UpdateHistogramFromDict(
        'MappedCSSProperties', ReadCssProperties(USE_COUNTER_CPP_PATH),
        USE_COUNTER_CPP_PATH, os.path.basename(__file__))