tools/metrics/common/diff_util.py

   1 # Copyright 2014 The Chromium Authors. All rights reserved.
   2 # Use of this source code is governed by a BSD-style license that can be
   3 # found in the LICENSE file.
   4
   5 """Utility functions for prompting user if changes automatically applied to some
   6 user-managed files are correct.
   7 """
   8
   9 import logging
  10 import os
  11 import webbrowser
  12
  13 from difflib import HtmlDiff
  14 from tempfile import NamedTemporaryFile
  15
  16
  17 def PromptUserToAcceptDiff(old_text, new_text, prompt):
  18   """Displays a difference in two strings (old and new file contents) to the
  19   user and asks whether the new version is acceptable.
  20
  21   Args:
  22     old_text: A string containing old file contents.
  23     new_text: A string containing new file contents.
  24     prompt: Text that should be displayed to the user, asking whether the new
  25             file contents should be accepted.
  26
  27   Returns:
  28     True is user accepted the changes or there were no changes, False otherwise.
  29   """
  30   logging.info('Computing diff...')
  31   if old_text == new_text:
  32     logging.info('No changes detected')
  33     return True
  34   html_diff = HtmlDiff(wrapcolumn=80).make_file(
  35       old_text.splitlines(), new_text.splitlines(), fromdesc='Original',
  36       todesc='Updated', context=True, numlines=5)
  37   temp = NamedTemporaryFile(suffix='.html', delete=False)
  38   try:
  39     temp.write(html_diff)
  40     temp.close()  # Close the file so the browser process can access it.
  41     webbrowser.open('file://' + temp.name)
  42     print prompt
  43     response = raw_input('(Y/n): ').strip().lower()
  44   finally:
  45     temp.close()  # May be called on already closed file.
  46     os.remove(temp.name)
  47   return response == 'y' or response == ''