xref: /llvm-project/clang/tools/clang-format/clang-format-diff.py (revision 38a5bd4115afbe022a99334c7880f30a8ffd7c4a) 
1#!/usr/bin/env python3
2#
3#===- clang-format-diff.py - ClangFormat Diff Reformatter ----*- python -*--===#
4#
5# Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
6# See https://llvm.org/LICENSE.txt for license information.
7# SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
8#
9#===------------------------------------------------------------------------===#
10
11"""
12This script reads input from a unified diff and reformats all the changed
13lines. This is useful to reformat all the lines touched by a specific patch.
14Example usage for git/svn users:
15
16  git diff -U0 --no-color --relative HEAD^ | clang-format-diff.py -p1 -i
17  svn diff --diff-cmd=diff -x-U0 | clang-format-diff.py -i
18
19It should be noted that the filename contained in the diff is used unmodified
20to determine the source file to update. Users calling this script directly
21should be careful to ensure that the path in the diff is correct relative to the
22current working directory.
23"""
24from __future__ import absolute_import, division, print_function
25
26import argparse
27import difflib
28import re
29import subprocess
30import sys
31
32if sys.version_info.major >= 3:
33    from io import StringIO
34else:
35    from io import BytesIO as StringIO
36
37
38def main():
39  parser = argparse.ArgumentParser(description=__doc__,
40                                   formatter_class=
41                                           argparse.RawDescriptionHelpFormatter)
42  parser.add_argument('-i', action='store_true', default=False,
43                      help='apply edits to files instead of displaying a diff')
44  parser.add_argument('-p', metavar='NUM', default=0,
45                      help='strip the smallest prefix containing P slashes')
46  parser.add_argument('-regex', metavar='PATTERN', default=None,
47                      help='custom pattern selecting file paths to reformat '
48                      '(case sensitive, overrides -iregex)')
49  parser.add_argument('-iregex', metavar='PATTERN', default=
50                      r'.*\.(cpp|cc|c\+\+|cxx|c|cl|h|hh|hpp|hxx|m|mm|inc|js|ts'
51                      r'|proto|protodevel|java|cs|json)',
52                      help='custom pattern selecting file paths to reformat '
53                      '(case insensitive, overridden by -regex)')
54  parser.add_argument('-sort-includes', action='store_true', default=False,
55                      help='let clang-format sort include blocks')
56  parser.add_argument('-v', '--verbose', action='store_true',
57                      help='be more verbose, ineffective without -i')
58  parser.add_argument('-style',
59                      help='formatting style to apply (LLVM, GNU, Google, Chromium, '
60                      'Microsoft, Mozilla, WebKit)')
61  parser.add_argument('-fallback-style',
62                      help='The name of the predefined style used as a'
63                      'fallback in case clang-format is invoked with'
64                      '-style=file, but can not find the .clang-format'
65                      'file to use.')
66  parser.add_argument('-binary', default='clang-format',
67                      help='location of binary to use for clang-format')
68  args = parser.parse_args()
69
70  # Extract changed lines for each file.
71  filename = None
72  lines_by_file = {}
73  for line in sys.stdin:
74    match = re.search(r'^\+\+\+\ (.*?/){%s}(\S*)' % args.p, line)
75    if match:
76      filename = match.group(2)
77    if filename is None:
78      continue
79
80    if args.regex is not None:
81      if not re.match('^%s$' % args.regex, filename):
82        continue
83    else:
84      if not re.match('^%s$' % args.iregex, filename, re.IGNORECASE):
85        continue
86
87    match = re.search(r'^@@.*\+(\d+)(,(\d+))?', line)
88    if match:
89      start_line = int(match.group(1))
90      line_count = 1
91      if match.group(3):
92        line_count = int(match.group(3))
93      if line_count == 0:
94        continue
95      end_line = start_line + line_count - 1
96      lines_by_file.setdefault(filename, []).extend(
97          ['-lines', str(start_line) + ':' + str(end_line)])
98
99  # Reformat files containing changes in place.
100  for filename, lines in lines_by_file.items():
101    if args.i and args.verbose:
102      print('Formatting {}'.format(filename))
103    command = [args.binary, filename]
104    if args.i:
105      command.append('-i')
106    if args.sort_includes:
107      command.append('-sort-includes')
108    command.extend(lines)
109    if args.style:
110      command.extend(['-style', args.style])
111    if args.fallback_style:
112      command.extend(['-fallback-style', args.fallback_style])
113
114    try:
115      p = subprocess.Popen(command,
116                           stdout=subprocess.PIPE,
117                           stderr=None,
118                           stdin=subprocess.PIPE,
119                           universal_newlines=True)
120    except OSError as e:
121      # Give the user more context when clang-format isn't
122      # found/isn't executable, etc.
123      raise RuntimeError(
124        'Failed to run "%s" - %s"' % (" ".join(command), e.strerror))
125
126    stdout, stderr = p.communicate()
127    if p.returncode != 0:
128      sys.exit(p.returncode)
129
130    if not args.i:
131      with open(filename) as f:
132        code = f.readlines()
133      formatted_code = StringIO(stdout).readlines()
134      diff = difflib.unified_diff(code, formatted_code,
135                                  filename, filename,
136                                  '(before formatting)', '(after formatting)')
137      diff_string = ''.join(diff)
138      if len(diff_string) > 0:
139        sys.stdout.write(diff_string)
140
141if __name__ == '__main__':
142  main()
143