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1# Copyright (c) 2012 The Chromium Authors. All rights reserved.
2# Use of this source code is governed by a BSD-style license that can be
3# found in the LICENSE file.
4
5"""Checks C++ and Objective-C files for illegal includes."""
6
7
8
9import codecs
10import os
11import re
12
13import results
14from rules import Rule, MessageRule
15
16
17class CppChecker(object):
18
19  EXTENSIONS = [
20      '.h',
21      '.cc',
22      '.cpp',
23      '.m',
24      '.mm',
25  ]
26
27  # The maximum number of non-include lines we can see before giving up.
28  _MAX_UNINTERESTING_LINES = 50
29
30  # The maximum line length, this is to be efficient in the case of very long
31  # lines (which can't be #includes).
32  _MAX_LINE_LENGTH = 128
33
34  # This regular expression will be used to extract filenames from include
35  # statements.
36  _EXTRACT_INCLUDE_PATH = re.compile(
37      r'[ \t]*#[ \t]*(?:include|import)[ \t]+"(.*)"')
38
39  def __init__(self, verbose, resolve_dotdot=False, root_dir=''):
40    self._verbose = verbose
41    self._resolve_dotdot = resolve_dotdot
42    self._root_dir = root_dir
43
44  def CheckLine(self, rules, line, dependee_path, fail_on_temp_allow=False):
45    """Checks the given line with the given rule set.
46
47    Returns a tuple (is_include, dependency_violation) where
48    is_include is True only if the line is an #include or #import
49    statement, and dependency_violation is an instance of
50    results.DependencyViolation if the line violates a rule, or None
51    if it does not.
52    """
53    found_item = self._EXTRACT_INCLUDE_PATH.match(line)
54    if not found_item:
55      return False, None  # Not a match
56
57    include_path = found_item.group(1)
58
59    if '\\' in include_path:
60      return True, results.DependencyViolation(
61          include_path,
62          MessageRule('Include paths may not include backslashes.'),
63          rules)
64
65    if '/' not in include_path:
66      # Don't fail when no directory is specified. We may want to be more
67      # strict about this in the future.
68      if self._verbose:
69        print(' WARNING: include specified with no directory: ' + include_path)
70      return True, None
71
72    if self._resolve_dotdot and '../' in include_path:
73      dependee_dir = os.path.dirname(dependee_path)
74      include_path = os.path.join(dependee_dir, include_path)
75      include_path = os.path.relpath(include_path, self._root_dir)
76
77    rule = rules.RuleApplyingTo(include_path, dependee_path)
78    if (rule.allow == Rule.DISALLOW or
79        (fail_on_temp_allow and rule.allow == Rule.TEMP_ALLOW)):
80      return True, results.DependencyViolation(include_path, rule, rules)
81    return True, None
82
83  def CheckFile(self, rules, filepath):
84    if self._verbose:
85      print('Checking: ' + filepath)
86
87    dependee_status = results.DependeeStatus(filepath)
88    ret_val = ''  # We'll collect the error messages in here
89    last_include = 0
90    with codecs.open(filepath, encoding='utf-8') as f:
91      in_if0 = 0
92      for line_num, line in enumerate(f):
93        if line_num - last_include > self._MAX_UNINTERESTING_LINES:
94          break
95
96        line = line.strip()
97
98        # Check to see if we're at / inside an #if 0 block
99        if line.startswith('#if 0'):
100          in_if0 += 1
101          continue
102        if in_if0 > 0:
103          if line.startswith('#if'):
104            in_if0 += 1
105          elif line.startswith('#endif'):
106            in_if0 -= 1
107          continue
108
109        is_include, violation = self.CheckLine(rules, line, filepath)
110        if is_include:
111          last_include = line_num
112        if violation:
113          dependee_status.AddViolation(violation)
114
115    return dependee_status
116
117  @staticmethod
118  def IsCppFile(file_path):
119    """Returns True iff the given path ends in one of the extensions
120    handled by this checker.
121    """
122    return os.path.splitext(file_path)[1] in CppChecker.EXTENSIONS
123
124  def ShouldCheck(self, file_path):
125    """Check if the new #include file path should be presubmit checked.
126
127    Args:
128      file_path: file path to be checked
129
130    Return:
131      bool: True if the file should be checked; False otherwise.
132    """
133    return self.IsCppFile(file_path)
134