1#!/usr/bin/env python
2# Copyright 2015 The Chromium Authors. All rights reserved.
3# Use of this source code is governed by a BSD-style license that can be
4# found in the LICENSE file.
5#
6# Script to apply fixits generated by clang. This is to work around the fact
7# that clang's -Xclang -fixit-recompile flag, which automatically applies fixits
8# and recompiles, doesn't work well with parallel invocations of clang.
9#
10# Usage:
11# 1. Enable parseable fixits and disable warnings as errors. Instructions for
12#    doing this vary based on the build environment, but for GN, warnings as
13#    errors can be disabled by setting treat_warnings_as_errors = false
14#    Enabling parseable fixits requires editing build/config/compiler/BUILD.gn
15#    and adding `-fdiagnostics-parseable-fixits` to cflags.
16# 2. Build everything and capture the output:
17#      ninja -C <build_directory> &> generated-fixits
18# 3. Apply the fixits with this script:
19#      python apply_fixits.py -p <build_directory> < generated-fixits
20
21import argparse
22import collections
23import fileinput
24import os
25import re
26import sys
27
28# fix-it:"../../base/threading/sequenced_worker_pool.h":{341:3-341:11}:""
29# Note that the file path is relative to the build directory.
30_FIXIT_RE = re.compile(r'^fix-it:"(?P<file>.+?)":'
31                       r'{(?P<start_line>\d+?):(?P<start_col>\d+?)-'
32                       r'(?P<end_line>\d+?):(?P<end_col>\d+?)}:'
33                       r'"(?P<text>.*?)"$')
34
35FixIt = collections.namedtuple(
36    'FixIt', ('start_line', 'start_col', 'end_line', 'end_col', 'text'))
37
38
39def main():
40  parser = argparse.ArgumentParser()
41  parser.add_argument(
42      '-p',
43      required=True,
44      help='path to the build directory to complete relative paths in fixits')
45  args = parser.parse_args()
46
47  fixits = collections.defaultdict(list)
48  for line in fileinput.input(['-']):
49    if not line.startswith('fix-it:'):
50      continue
51    m = _FIXIT_RE.match(line)
52    if not m:
53      continue
54    # The negative line numbers are a cheap hack so we can sort things in line
55    # order but reverse column order. Applying the fixits in reverse order makes
56    # things simpler, since offsets won't have to be adjusted as the text is
57    # changed.
58    fixits[m.group('file')].append(FixIt(
59        int(m.group('start_line')), -int(m.group('start_col')), int(m.group(
60            'end_line')), -int(m.group('end_col')), m.group('text')))
61  for k, v in fixits.iteritems():
62    v.sort()
63    with open(os.path.join(args.p, k), 'rb+') as f:
64      lines = f.readlines()
65      last_fixit = None
66      for fixit in v:
67        if fixit.start_line != fixit.end_line:
68          print 'error: multiline fixits not supported! file: %s, fixit: %s' % (
69              k, fixit)
70          sys.exit(1)
71        if fixit == last_fixit:
72          continue
73        last_fixit = fixit
74        # The line/column numbers emitted in fixit hints start at 1, so offset
75        # is appropriately.
76        line = lines[fixit.start_line - 1]
77        lines[fixit.start_line - 1] = (line[:-fixit.start_col - 1] + fixit.text
78                                       + line[-fixit.end_col - 1:])
79      f.seek(0)
80      f.truncate()
81      f.writelines(lines)
82
83
84if __name__ == '__main__':
85  sys.exit(main())
86