new_contents: #!/usr/bin/env python
  #
  #===- clang-format-diff.py - ClangFormat Diff Reformatter ----*- python -*--===#
  #
  #                     The LLVM Compiler Infrastructure
  #
  # This file is distributed under the University of Illinois Open Source
  # License. See LICENSE.TXT for details.
  #
  #===------------------------------------------------------------------------===#
  
  r"""
  ClangFormat Diff Reformatter
  ============================
  
  This script reads input from a unified diff and reformats all the changed
  lines. This is useful to reformat all the lines touched by a specific patch.
  Example usage for git/svn users:
  
    git diff -U0 HEAD^ | clang-format-diff.py -p1 -i
    svn diff --diff-cmd=diff -x-U0 | clang-format-diff.py -i
  
  """
  
  import argparse
  import difflib
  import re
  import string
  import subprocess
  import StringIO
  import sys
  
  
  # Change this to the full path if clang-format is not on the path.
  binary = 'clang-format'
  
  
  def main():
    parser = argparse.ArgumentParser(description=
                                     'Reformat changed lines in diff. Without -i '
                                     'option just output the diff that would be '
                                     'introduced.')
    parser.add_argument('-i', action='store_true', default=False,
                        help='apply edits to files instead of displaying a diff')
    parser.add_argument('-p', metavar='NUM', default=0,
                        help='strip the smallest prefix containing P slashes')
    parser.add_argument('-regex', metavar='PATTERN', default=None,
                        help='custom pattern selecting file paths to reformat '
                        '(case sensitive, overrides -iregex)')
    parser.add_argument('-iregex', metavar='PATTERN', default=
                        r'.*\.(cpp|cc|c\+\+|cxx|c|cl|h|hpp|m|mm|inc|js|ts|proto'
                        r'|protodevel|java)',
                        help='custom pattern selecting file paths to reformat '
                        '(case insensitive, overridden by -regex)')
    parser.add_argument('-sort-includes', action='store_true', default=False,
                        help='let clang-format sort include blocks')
    parser.add_argument('-v', '--verbose', action='store_true',
                        help='be more verbose, ineffective without -i')
    parser.add_argument(
        '-style',
        help=
        'formatting style to apply (LLVM, Google, Chromium, Mozilla, WebKit)')
    args = parser.parse_args()
  
    # Extract changed lines for each file.
    filename = None
    lines_by_file = {}
    for line in sys.stdin:
      match = re.search('^\+\+\+\ (.*?/){%s}(\S*)' % args.p, line)
      if match:
        filename = match.group(2)
      if filename == None:
        continue
  
      if args.regex is not None:
        if not re.match('^%s$' % args.regex, filename):
          continue
      else:
        if not re.match('^%s$' % args.iregex, filename, re.IGNORECASE):
          continue
  
      match = re.search('^@@.*\+(\d+)(,(\d+))?', line)
      if match:
        start_line = int(match.group(1))
        line_count = 1
        if match.group(3):
          line_count = int(match.group(3))
        if line_count == 0:
          continue
        end_line = start_line + line_count - 1;
        lines_by_file.setdefault(filename, []).extend(
            ['-lines', str(start_line) + ':' + str(end_line)])
  
    # Reformat files containing changes in place.
    for filename, lines in lines_by_file.iteritems():
      if args.i and args.verbose:
        print 'Formatting', filename
      command = [binary, filename]
      if args.i:
        command.append('-i')
      if args.sort_includes:
        command.append('-sort-includes')
      command.extend(lines)
      if args.style:
        command.extend(['-style', args.style])
      p = subprocess.Popen(command, stdout=subprocess.PIPE,
                           stderr=None, stdin=subprocess.PIPE)
      stdout, stderr = p.communicate()
      if p.returncode != 0:
        sys.exit(p.returncode);
  
      if not args.i:
        with open(filename) as f:
          code = f.readlines()
        formatted_code = StringIO.StringIO(stdout).readlines()
        diff = difflib.unified_diff(code, formatted_code,
                                    filename, filename,
                                    '(before formatting)', '(after formatting)')
        diff_string = string.join(diff, '')
        if len(diff_string) > 0:
          sys.stdout.write(diff_string)
  
  if __name__ == '__main__':
    main()
  
subject: Add clang-format-diff.py from the LLVM svn