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1#!/usr/bin/env python
2
3# Copyright (c) 2017 The WebRTC project authors. All Rights Reserved.
4#
5# Use of this source code is governed by a BSD-style license
6# that can be found in the LICENSE file in the root of the source
7# tree. An additional intellectual property rights grant can be found
8# in the file PATENTS.  All contributing project authors may
9# be found in the AUTHORS file in the root of the source tree.
10
11import argparse
12import collections
13import os
14import re
15import sys
16
17
18# TARGET_RE matches a GN target, and extracts the target name and the contents.
19TARGET_RE = re.compile(r'(?P<indent>\s*)\w+\("(?P<target_name>\w+)"\) {'
20                       r'(?P<target_contents>.*?)'
21                       r'(?P=indent)}',
22                       re.MULTILINE | re.DOTALL)
23
24# SOURCES_RE matches a block of sources inside a GN target.
25SOURCES_RE = re.compile(r'sources \+?= \[(?P<sources>.*?)\]',
26                        re.MULTILINE | re.DOTALL)
27
28ERROR_MESSAGE = ("{build_file_path} in target '{target_name}':\n"
29                 "  Source file '{source_file}'\n"
30                 "  crosses boundary of package '{subpackage}'.")
31
32
33class PackageBoundaryViolation(
34    collections.namedtuple('PackageBoundaryViolation',
35        'build_file_path target_name source_file subpackage')):
36  def __str__(self):
37    return ERROR_MESSAGE.format(**self._asdict())
38
39
40def _BuildSubpackagesPattern(packages, query):
41  """Returns a regular expression that matches source files inside subpackages
42  of the given query."""
43  query += os.path.sep
44  length = len(query)
45  pattern = r'\s*"(?P<source_file>(?P<subpackage>'
46  pattern += '|'.join(re.escape(package[length:].replace(os.path.sep, '/'))
47                      for package in packages if package.startswith(query))
48  pattern += r')/[\w\./]*)"'
49  return re.compile(pattern)
50
51
52def _ReadFileAndPrependLines(file_path):
53  """Reads the contents of a file."""
54  with open(file_path) as f:
55    return "".join(f.readlines())
56
57
58def _CheckBuildFile(build_file_path, packages):
59  """Iterates over all the targets of the given BUILD.gn file, and verifies that
60  the source files referenced by it don't belong to any of it's subpackages.
61  Returns an iterator over PackageBoundaryViolations for this package.
62  """
63  package = os.path.dirname(build_file_path)
64  subpackages_re = _BuildSubpackagesPattern(packages, package)
65
66  build_file_contents = _ReadFileAndPrependLines(build_file_path)
67  for target_match in TARGET_RE.finditer(build_file_contents):
68    target_name = target_match.group('target_name')
69    target_contents = target_match.group('target_contents')
70    for sources_match in SOURCES_RE.finditer(target_contents):
71      sources = sources_match.group('sources')
72      for subpackages_match in subpackages_re.finditer(sources):
73        subpackage = subpackages_match.group('subpackage')
74        source_file = subpackages_match.group('source_file')
75        if subpackage:
76          yield PackageBoundaryViolation(build_file_path,
77                                         target_name, source_file, subpackage)
78
79
80def CheckPackageBoundaries(root_dir, build_files=None):
81  packages = [root for root, _, files in os.walk(root_dir)
82              if 'BUILD.gn' in files]
83
84  if build_files is not None:
85    for build_file_path in build_files:
86      assert build_file_path.startswith(root_dir)
87  else:
88    build_files = [os.path.join(package, 'BUILD.gn') for package in packages]
89
90  messages = []
91  for build_file_path in build_files:
92    messages.extend(_CheckBuildFile(build_file_path, packages))
93  return messages
94
95
96def main(argv):
97  parser = argparse.ArgumentParser(
98      description='Script that checks package boundary violations in GN '
99                  'build files.')
100
101  parser.add_argument('root_dir', metavar='ROOT_DIR',
102                      help='The root directory that contains all BUILD.gn '
103                           'files to be processed.')
104  parser.add_argument('build_files', metavar='BUILD_FILE', nargs='*',
105                      help='A list of BUILD.gn files to be processed. If no '
106                           'files are given, all BUILD.gn files under ROOT_DIR '
107                           'will be processed.')
108  parser.add_argument('--max_messages', type=int, default=None,
109                      help='If set, the maximum number of violations to be '
110                           'displayed.')
111
112  args = parser.parse_args(argv)
113
114  messages = CheckPackageBoundaries(args.root_dir, args.build_files)
115  messages = messages[:args.max_messages]
116
117  for i, message in enumerate(messages):
118    if i > 0:
119      print
120    print message
121
122  return bool(messages)
123
124
125if __name__ == '__main__':
126  sys.exit(main(sys.argv[1:]))
127