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