xref: /llvm-project/clang/tools/clang-format/clang-format-diff.py (revision 68367141dd91ee71f50418f28ea358519cd6613d)
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|cppm|ccm|cxxm|c\+\+m|c|cl|h|hh|hpp|hxx'
51                      r'|m|mm|inc|js|ts|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(2):
92        line_count = int(match.group(2))
93        # The input is something like
94        #
95        # @@ -1, +0,0 @@
96        #
97        # which means no lines were added.
98        if line_count == 0:
99          continue
100      # Also format lines range if line_count is 0 in case of deleting
101      # surrounding statements.
102      end_line = start_line
103      if line_count != 0:
104        end_line += line_count - 1
105      lines_by_file.setdefault(filename, []).extend(
106          ['-lines', str(start_line) + ':' + str(end_line)])
107
108  # Reformat files containing changes in place.
109  for filename, lines in lines_by_file.items():
110    if args.i and args.verbose:
111      print('Formatting {}'.format(filename))
112    command = [args.binary, filename]
113    if args.i:
114      command.append('-i')
115    if args.sort_includes:
116      command.append('-sort-includes')
117    command.extend(lines)
118    if args.style:
119      command.extend(['-style', args.style])
120    if args.fallback_style:
121      command.extend(['-fallback-style', args.fallback_style])
122
123    try:
124      p = subprocess.Popen(command,
125                           stdout=subprocess.PIPE,
126                           stderr=None,
127                           stdin=subprocess.PIPE,
128                           universal_newlines=True)
129    except OSError as e:
130      # Give the user more context when clang-format isn't
131      # found/isn't executable, etc.
132      raise RuntimeError(
133        'Failed to run "%s" - %s"' % (" ".join(command), e.strerror))
134
135    stdout, stderr = p.communicate()
136    if p.returncode != 0:
137      sys.exit(p.returncode)
138
139    if not args.i:
140      with open(filename) as f:
141        code = f.readlines()
142      formatted_code = StringIO(stdout).readlines()
143      diff = difflib.unified_diff(code, formatted_code,
144                                  filename, filename,
145                                  '(before formatting)', '(after formatting)')
146      diff_string = ''.join(diff)
147      if len(diff_string) > 0:
148        sys.stdout.write(diff_string)
149
150if __name__ == '__main__':
151  main()
152