xref: /llvm-project/clang/tools/clang-format/clang-format-diff.py (revision d14e7ee3d17cfa60d44256d742c10e9949a6048f)
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
37def process_subprocess_result(proc, args):
38  stdout, stderr = proc.communicate()
39  if proc.returncode != 0:
40    sys.exit(proc.returncode)
41  if not args.i:
42    with open(filename) as f:
43      code = f.readlines()
44    formatted_code = StringIO(stdout).readlines()
45    diff = difflib.unified_diff(code, formatted_code,
46                                filename, filename,
47                                '(before formatting)',
48                                '(after formatting)')
49    diff_string = ''.join(diff)
50    if len(diff_string) > 0:
51      sys.stdout.write(diff_string)
52
53def main():
54  parser = argparse.ArgumentParser(description=__doc__,
55                                   formatter_class=
56                                           argparse.RawDescriptionHelpFormatter)
57  parser.add_argument('-i', action='store_true', default=False,
58                      help='apply edits to files instead of displaying a diff')
59  parser.add_argument('-p', metavar='NUM', default=0,
60                      help='strip the smallest prefix containing P slashes')
61  parser.add_argument('-regex', metavar='PATTERN', default=None,
62                      help='custom pattern selecting file paths to reformat '
63                      '(case sensitive, overrides -iregex)')
64  parser.add_argument('-iregex', metavar='PATTERN', default=
65                      r'.*\.(cpp|cc|c\+\+|cxx|cppm|ccm|cxxm|c\+\+m|c|cl|h|hh|hpp|hxx'
66                      r'|m|mm|inc|js|ts|proto|protodevel|java|cs|json)',
67                      help='custom pattern selecting file paths to reformat '
68                      '(case insensitive, overridden by -regex)')
69  parser.add_argument('-sort-includes', action='store_true', default=False,
70                      help='let clang-format sort include blocks')
71  parser.add_argument('-v', '--verbose', action='store_true',
72                      help='be more verbose, ineffective without -i')
73  parser.add_argument('-style',
74                      help='formatting style to apply (LLVM, GNU, Google, Chromium, '
75                      'Microsoft, Mozilla, WebKit)')
76  parser.add_argument('-fallback-style',
77                      help='The name of the predefined style used as a'
78                      'fallback in case clang-format is invoked with'
79                      '-style=file, but can not find the .clang-format'
80                      'file to use.')
81  parser.add_argument('-binary', default='clang-format',
82                      help='location of binary to use for clang-format')
83  parser.add_argument('-j', default=1, type=int, metavar='N',
84                      help='number of concurrent clang-format processes to spawn in '
85                      'parallel')
86  args = parser.parse_args()
87
88  # Extract changed lines for each file.
89  filename = None
90  lines_by_file = {}
91  for line in sys.stdin:
92    match = re.search(r'^\+\+\+\ (.*?/){%s}(\S*)' % args.p, line)
93    if match:
94      filename = match.group(2)
95    if filename is None:
96      continue
97
98    if args.regex is not None:
99      if not re.match('^%s$' % args.regex, filename):
100        continue
101    else:
102      if not re.match('^%s$' % args.iregex, filename, re.IGNORECASE):
103        continue
104
105    match = re.search(r'^@@.*\+(\d+)(?:,(\d+))?', line)
106    if match:
107      start_line = int(match.group(1))
108      line_count = 1
109      if match.group(2):
110        line_count = int(match.group(2))
111        # The input is something like
112        #
113        # @@ -1, +0,0 @@
114        #
115        # which means no lines were added.
116        if line_count == 0:
117          continue
118      # Also format lines range if line_count is 0 in case of deleting
119      # surrounding statements.
120      end_line = start_line
121      if line_count != 0:
122        end_line += line_count - 1
123      lines_by_file.setdefault(filename, []).extend(
124          ['-lines', str(start_line) + ':' + str(end_line)])
125
126  # Reformat files containing changes in place.
127  lbf = list(lines_by_file.items())
128  procs = [None for i in range(args.j)]
129  while lbf:
130    spawned_one = False
131    for i, proc in enumerate(procs):
132      if not lbf:
133        break
134      if proc is not None and proc.poll() is not None:
135        process_subprocess_result(proc, args)
136        # Set to None to flag the slot as free to start a new process
137        procs[i] = None
138        proc = None
139      if proc is None:
140        filename, lines = lbf.pop()
141        spawned_one = True
142        if args.i and args.verbose:
143          print('Formatting {}'.format(filename))
144        command = [args.binary, filename]
145        if args.i:
146          command.append('-i')
147        if args.sort_includes:
148          command.append('-sort-includes')
149        command.extend(lines)
150        if args.style:
151          command.extend(['-style', args.style])
152        if args.fallback_style:
153          command.extend(['-fallback-style', args.fallback_style])
154        try:
155          procs[i] = subprocess.Popen(command,
156                                      stdout=subprocess.PIPE,
157                                      stderr=None,
158                                      stdin=subprocess.PIPE,
159                                      universal_newlines=True)
160        except OSError as e:
161          # Give the user more context when clang-format isn't
162          # found/isn't executable, etc.
163          raise RuntimeError(
164              'Failed to run "%s" - %s"' % (" ".join(command), e.strerror))
165    # If we didn't spawn a single process after iterating through the whole
166    # list, wait on one of them to finish until we iterate through again, to
167    # prevent spinning in the case where we have a small number of jobs.
168    if not spawned_one:
169      procs[0].wait()
170  # Be sure not to leave any stray processes when exiting.
171  for proc in procs:
172    if proc:
173      proc.wait()
174      process_subprocess_result(proc, args)
175
176if __name__ == '__main__':
177  main()
178