tools/checkdeps/cpp_checker.py

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