text: # -*- coding: utf-8 -*-
  #
  # Copyright (C) 2009, 2010, 2012 Google Inc. All rights reserved.
  # Copyright (C) 2009 Torch Mobile Inc.
  # Copyright (C) 2009 Apple Inc. All rights reserved.
  # Copyright (C) 2010 Chris Jerdonek (cjerdonek@webkit.org)
  #
  # Redistribution and use in source and binary forms, with or without
  # modification, are permitted provided that the following conditions are
  # met:
  #
  #    * Redistributions of source code must retain the above copyright
  # notice, this list of conditions and the following disclaimer.
  #    * Redistributions in binary form must reproduce the above
  # copyright notice, this list of conditions and the following disclaimer
  # in the documentation and/or other materials provided with the
  # distribution.
  #    * Neither the name of Google Inc. nor the names of its
  # contributors may be used to endorse or promote products derived from
  # this software without specific prior written permission.
  #
  # THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  # "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  # LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
  # A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
  # OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
  # SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
  # LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  # DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  # THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  # (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  # OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  
  # This is the modified version of Google's cpplint. The original code is
  # http://google-styleguide.googlecode.com/svn/trunk/cpplint/cpplint.py
  
  """Support for check-webkit-style."""
  
  import math  # for log
  import os
  import os.path
  import re
  import sre_compile
  import string
  import unicodedata
  
  from webkitpy.common.memoized import memoized
  from webkitpy.common.system.filesystem import FileSystem
  
  # Headers that we consider STL headers.
  _STL_HEADERS = frozenset([
      'algobase.h', 'algorithm', 'alloc.h', 'bitset', 'deque', 'exception',
      'function.h', 'functional', 'hash_map', 'hash_map.h', 'hash_set',
      'hash_set.h', 'iterator', 'list', 'list.h', 'map', 'memory', 'pair.h',
      'pthread_alloc', 'queue', 'set', 'set.h', 'sstream', 'stack',
      'stl_alloc.h', 'stl_relops.h', 'type_traits.h',
      'utility', 'vector', 'vector.h',
  ])
  
  
  # Non-STL C++ system headers.
  _CPP_HEADERS = frozenset([
      'algo.h', 'builtinbuf.h', 'bvector.h', 'cassert', 'cctype',
      'cerrno', 'cfloat', 'ciso646', 'climits', 'clocale', 'cmath',
      'complex', 'complex.h', 'csetjmp', 'csignal', 'cstdarg', 'cstddef',
      'cstdio', 'cstdlib', 'cstring', 'ctime', 'cwchar', 'cwctype',
      'defalloc.h', 'deque.h', 'editbuf.h', 'exception', 'fstream',
      'fstream.h', 'hashtable.h', 'heap.h', 'indstream.h', 'iomanip',
      'iomanip.h', 'ios', 'iosfwd', 'iostream', 'iostream.h', 'istream.h',
      'iterator.h', 'limits', 'map.h', 'multimap.h', 'multiset.h',
      'numeric', 'ostream.h', 'parsestream.h', 'pfstream.h', 'PlotFile.h',
      'procbuf.h', 'pthread_alloc.h', 'rope', 'rope.h', 'ropeimpl.h',
      'SFile.h', 'slist', 'slist.h', 'stack.h', 'stdexcept',
      'stdiostream.h', 'streambuf.h', 'stream.h', 'strfile.h', 'string',
      'strstream', 'strstream.h', 'tempbuf.h', 'tree.h', 'typeinfo', 'valarray',
  ])
  
  
  # Assertion macros.  These are defined in base/logging.h and
  # testing/base/gunit.h.  Note that the _M versions need to come first
  # for substring matching to work.
  _CHECK_MACROS = [
      'DCHECK', 'CHECK',
      'EXPECT_TRUE_M', 'EXPECT_TRUE',
      'ASSERT_TRUE_M', 'ASSERT_TRUE',
      'EXPECT_FALSE_M', 'EXPECT_FALSE',
      'ASSERT_FALSE_M', 'ASSERT_FALSE',
  ]
  
  # Replacement macros for CHECK/DCHECK/EXPECT_TRUE/EXPECT_FALSE
  _CHECK_REPLACEMENT = dict([(m, {}) for m in _CHECK_MACROS])
  
  for op, replacement in [('==', 'EQ'), ('!=', 'NE'),
                          ('>=', 'GE'), ('>', 'GT'),
                          ('<=', 'LE'), ('<', 'LT')]:
      _CHECK_REPLACEMENT['DCHECK'][op] = 'DCHECK_%s' % replacement
      _CHECK_REPLACEMENT['CHECK'][op] = 'CHECK_%s' % replacement
      _CHECK_REPLACEMENT['EXPECT_TRUE'][op] = 'EXPECT_%s' % replacement
      _CHECK_REPLACEMENT['ASSERT_TRUE'][op] = 'ASSERT_%s' % replacement
      _CHECK_REPLACEMENT['EXPECT_TRUE_M'][op] = 'EXPECT_%s_M' % replacement
      _CHECK_REPLACEMENT['ASSERT_TRUE_M'][op] = 'ASSERT_%s_M' % replacement
  
  for op, inv_replacement in [('==', 'NE'), ('!=', 'EQ'),
                              ('>=', 'LT'), ('>', 'LE'),
                              ('<=', 'GT'), ('<', 'GE')]:
      _CHECK_REPLACEMENT['EXPECT_FALSE'][op] = 'EXPECT_%s' % inv_replacement
      _CHECK_REPLACEMENT['ASSERT_FALSE'][op] = 'ASSERT_%s' % inv_replacement
      _CHECK_REPLACEMENT['EXPECT_FALSE_M'][op] = 'EXPECT_%s_M' % inv_replacement
      _CHECK_REPLACEMENT['ASSERT_FALSE_M'][op] = 'ASSERT_%s_M' % inv_replacement
  
  _DEPRECATED_MACROS = [
      ['ASSERT', 'DCHECK or its variants'],
      ['ASSERT_UNUSED', 'DCHECK or its variants'],
      ['ASSERT_NOT_REACHED', 'NOTREACHED'],
      ['ASSERT_WITH_SECURITY_IMPLICATION', 'SECURITY_DCHECK'],
      ['WTF_LOG', 'DVLOG']
  ]
  
  # These constants define types of headers for use with
  # _IncludeState.check_next_include_order().
  _PRIMARY_HEADER = 0
  _OTHER_HEADER = 1
  _MOC_HEADER = 2
  
  
  # The regexp compilation caching is inlined in all regexp functions for
  # performance reasons; factoring it out into a separate function turns out
  # to be noticeably expensive.
  _regexp_compile_cache = {}
  
  
  def match(pattern, s):
      """Matches the string with the pattern, caching the compiled regexp."""
      if not pattern in _regexp_compile_cache:
          _regexp_compile_cache[pattern] = sre_compile.compile(pattern)
      return _regexp_compile_cache[pattern].match(s)
  
  
  def search(pattern, s):
      """Searches the string for the pattern, caching the compiled regexp."""
      if not pattern in _regexp_compile_cache:
          _regexp_compile_cache[pattern] = sre_compile.compile(pattern)
      return _regexp_compile_cache[pattern].search(s)
  
  
  def sub(pattern, replacement, s):
      """Substitutes occurrences of a pattern, caching the compiled regexp."""
      if not pattern in _regexp_compile_cache:
          _regexp_compile_cache[pattern] = sre_compile.compile(pattern)
      return _regexp_compile_cache[pattern].sub(replacement, s)
  
  
  def subn(pattern, replacement, s):
      """Substitutes occurrences of a pattern, caching the compiled regexp."""
      if not pattern in _regexp_compile_cache:
          _regexp_compile_cache[pattern] = sre_compile.compile(pattern)
      return _regexp_compile_cache[pattern].subn(replacement, s)
  
  
  def iteratively_replace_matches_with_char(pattern, char_replacement, s):
      """Returns the string with replacement done.
  
      Every character in the match is replaced with char.
      Due to the iterative nature, pattern should not match char or
      there will be an infinite loop.
  
      Example:
        pattern = r'<[^>]>' # template parameters
        char_replacement =  '_'
        s =     'A<B<C, D>>'
        Returns 'A_________'
  
      Args:
        pattern: The regex to match.
        char_replacement: The character to put in place of every
                          character of the match.
        s: The string on which to do the replacements.
  
      Returns:
        True, if the given line is blank.
      """
      while True:
          matched = search(pattern, s)
          if not matched:
              return s
          start_match_index = matched.start(0)
          end_match_index = matched.end(0)
          match_length = end_match_index - start_match_index
          s = s[:start_match_index] + char_replacement * match_length + s[end_match_index:]
  
  
  def _find_in_lines(regex, lines, start_position, not_found_position):
      """Does a find starting at start position and going forward until
      a match is found.
  
      Returns the position where the regex started.
      """
      current_row = start_position.row
  
      # Start with the given row and trim off everything before what should be matched.
      current_line = lines[start_position.row][start_position.column:]
      starting_offset = start_position.column
      while True:
          found_match = search(regex, current_line)
          if found_match:
              return Position(current_row, starting_offset + found_match.start())
  
          # A match was not found so continue forward.
          current_row += 1
          starting_offset = 0
          if current_row >= len(lines):
              return not_found_position
          current_line = lines[current_row]
  
  
  def _rfind_in_lines(regex, lines, start_position, not_found_position):
      """Does a reverse find starting at start position and going backwards until
      a match is found.
  
      Returns the position where the regex ended.
      """
      # Put the regex in a group and proceed it with a greedy expression that
      # matches anything to ensure that we get the last possible match in a line.
      last_in_line_regex = r'.*(' + regex + ')'
      current_row = start_position.row
  
      # Start with the given row and trim off everything past what may be matched.
      current_line = lines[start_position.row][:start_position.column]
      while True:
          found_match = match(last_in_line_regex, current_line)
          if found_match:
              return Position(current_row, found_match.end(1))
  
          # A match was not found so continue backward.
          current_row -= 1
          if current_row < 0:
              return not_found_position
          current_line = lines[current_row]
  
  
  def _convert_to_lower_with_underscores(text):
      """Converts all text strings in camelCase or PascalCase to lowers with underscores."""
  
      # First add underscores before any capital letter followed by a lower case letter
      # as long as it is in a word.
      # (This put an underscore before Password but not P and A in WPAPassword).
      text = sub(r'(?<=[A-Za-z0-9])([A-Z])(?=[a-z])', r'_\1', text)
  
      # Next add underscores before capitals at the end of words if it was
      # preceded by lower case letter or number.
      # (This puts an underscore before A in isA but not A in CBA).
      text = sub(r'(?<=[a-z0-9])([A-Z])(?=\b)', r'_\1', text)
  
      # Next add underscores when you have a capital letter which is followed by a capital letter
      # but is not proceeded by one. (This puts an underscore before A in 'WordADay').
      text = sub(r'(?<=[a-z0-9])([A-Z][A-Z_])', r'_\1', text)
  
      return text.lower()
  
  
  def _create_acronym(text):
      """Creates an acronym for the given text."""
      # Removes all lower case letters except those starting words.
      text = sub(r'(?<!\b)[a-z]', '', text)
      return text.upper()
  
  
  def up_to_unmatched_closing_paren(s):
      """Splits a string into two parts up to first unmatched ')'.
  
      Args:
        s: a string which is a substring of line after '('
        (e.g., "a == (b + c))").
  
      Returns:
        A pair of strings (prefix before first unmatched ')',
        remainder of s after first unmatched ')'), e.g.,
        up_to_unmatched_closing_paren("a == (b + c)) { ")
        returns "a == (b + c)", " {".
        Returns None, None if there is no unmatched ')'
  
      """
      i = 1
      for pos, c in enumerate(s):
          if c == '(':
              i += 1
          elif c == ')':
              i -= 1
              if i == 0:
                  return s[:pos], s[pos + 1:]
      return None, None
  
  
  class _IncludeState(dict):
      """Tracks line numbers for includes, and the order in which includes appear.
  
      As a dict, an _IncludeState object serves as a mapping between include
      filename and line number on which that file was included.
  
      Call check_next_include_order() once for each header in the file, passing
      in the type constants defined above. Calls in an illegal order will
      raise an _IncludeError with an appropriate error message.
  
      """
      # self._section will move monotonically through this set. If it ever
      # needs to move backwards, check_next_include_order will raise an error.
      _INITIAL_SECTION = 0
      _PRIMARY_SECTION = 1
      _OTHER_SECTION = 2
  
      _TYPE_NAMES = {
          _PRIMARY_HEADER: 'header this file implements',
          _OTHER_HEADER: 'other header',
          _MOC_HEADER: 'moc file',
      }
      _SECTION_NAMES = {
          _INITIAL_SECTION: "... nothing.",
          _PRIMARY_SECTION: 'a header this file implements.',
          _OTHER_SECTION: 'other header.',
      }
  
      def __init__(self):
          dict.__init__(self)
          self._section = self._INITIAL_SECTION
          self._visited_primary_section = False
          self.header_types = dict()
  
      def visited_primary_section(self):
          return self._visited_primary_section
  
      def check_next_include_order(self, header_type, file_is_header, primary_header_exists):
          """Returns a non-empty error message if the next header is out of order.
  
          This function also updates the internal state to be ready to check
          the next include.
  
          Args:
            header_type: One of the _XXX_HEADER constants defined above.
            file_is_header: Whether the file that owns this _IncludeState is itself a header
  
          Returns:
            The empty string if the header is in the right order, or an
            error message describing what's wrong.
  
          """
          if header_type == _PRIMARY_HEADER and file_is_header:
              return 'Header file should not contain itself.'
          if header_type == _MOC_HEADER:
              return ''
  
          error_message = ''
          if self._section != self._OTHER_SECTION:
              before_error_message = ('Found %s before %s' %
                                      (self._TYPE_NAMES[header_type],
                                       self._SECTION_NAMES[self._section + 1]))
          after_error_message = ('Found %s after %s' %
                                 (self._TYPE_NAMES[header_type],
                                  self._SECTION_NAMES[self._section]))
  
          if header_type == _PRIMARY_HEADER:
              if self._section >= self._PRIMARY_SECTION:
                  error_message = after_error_message
              self._section = self._PRIMARY_SECTION
              self._visited_primary_section = True
          else:
              assert header_type == _OTHER_HEADER
              if not file_is_header and self._section < self._PRIMARY_SECTION:
                  if primary_header_exists:
                      error_message = before_error_message
              self._section = self._OTHER_SECTION
  
          return error_message
  
  
  class Position(object):
      """Holds the position of something."""
  
      def __init__(self, row, column):
          self.row = row
          self.column = column
  
      def __str__(self):
          return '(%s, %s)' % (self.row, self.column)
  
      def __cmp__(self, other):
          return self.row.__cmp__(other.row) or self.column.__cmp__(other.column)
  
  
  class Parameter(object):
      """Information about one function parameter."""
  
      def __init__(self, parameter, parameter_name_index, row):
          self.type = parameter[:parameter_name_index].strip()
          # Remove any initializers from the parameter name (e.g. int i = 5).
          self.name = sub(r'=.*', '', parameter[parameter_name_index:]).strip()
          self.row = row
  
      @memoized
      def lower_with_underscores_name(self):
          """Returns the parameter name in the lower with underscores format."""
          return _convert_to_lower_with_underscores(self.name)
  
  
  class SingleLineView(object):
      """Converts multiple lines into a single line (with line breaks replaced by a
         space) to allow for easier searching."""
  
      def __init__(self, lines, start_position, end_position):
          """Create a SingleLineView instance.
  
          Args:
            lines: a list of multiple lines to combine into a single line.
            start_position: offset within lines of where to start the single line.
            end_position: just after where to end (like a slice operation).
          """
          # Get the rows of interest.
          trimmed_lines = lines[start_position.row:end_position.row + 1]
  
          # Remove the columns on the last line that aren't included.
          trimmed_lines[-1] = trimmed_lines[-1][:end_position.column]
  
          # Remove the columns on the first line that aren't included.
          trimmed_lines[0] = trimmed_lines[0][start_position.column:]
  
          # Create a single line with all of the parameters.
          self.single_line = ' '.join(trimmed_lines)
          self.single_line = _RE_PATTERN_CLEANSE_MULTIPLE_STRINGS.sub('""', self.single_line)
  
          # Keep the row lengths, so we can calculate the original row number
          # given a column in the single line (adding 1 due to the space added
          # during the join).
          self._row_lengths = [len(line) + 1 for line in trimmed_lines]
          self._starting_row = start_position.row
  
      def convert_column_to_row(self, single_line_column_number):
          """Convert the column number from the single line into the original
          line number.
  
          Special cases:
          * Columns in the added spaces are considered part of the previous line.
          * Columns beyond the end of the line are consider part the last line
          in the view."""
          total_columns = 0
          row_offset = 0
          while row_offset < len(self._row_lengths) - 1 and single_line_column_number >= total_columns + self._row_lengths[row_offset]:
              total_columns += self._row_lengths[row_offset]
              row_offset += 1
          return self._starting_row + row_offset
  
  
  def create_skeleton_parameters(all_parameters):
      """Converts a parameter list to a skeleton version.
  
      The skeleton only has one word for the parameter name, one word for the type,
      and commas after each parameter and only there. Everything in the skeleton
      remains in the same columns as the original."""
      all_simplifications = (
          # Remove template parameters, function declaration parameters, etc.
          r'(<[^<>]*?>)|(\([^\(\)]*?\))|(\{[^\{\}]*?\})',
          # Remove all initializers.
          r'=[^,]*',
          # Remove :: and everything before it.
          r'[^,]*::',
          # Remove modifiers like &, *.
          r'[&*]',
          # Remove const modifiers.
          r'\bconst\s+(?=[A-Za-z])',
          # Remove numerical modifiers like long.
          r'\b(unsigned|long|short)\s+(?=unsigned|long|short|int|char|double|float)')
  
      skeleton_parameters = all_parameters
      for simplification in all_simplifications:
          skeleton_parameters = iteratively_replace_matches_with_char(simplification, ' ', skeleton_parameters)
      # If there are any parameters, then add a , after the last one to
      # make a regular pattern of a , following every parameter.
      if skeleton_parameters.strip():
          skeleton_parameters += ','
      return skeleton_parameters
  
  
  def find_parameter_name_index(skeleton_parameter):
      """Determines where the parameter name starts given the skeleton parameter."""
      # The first space from the right in the simplified parameter is where the parameter
      # name starts unless the first space is before any content in the simplified parameter.
      before_name_index = skeleton_parameter.rstrip().rfind(' ')
      if before_name_index != -1 and skeleton_parameter[:before_name_index].strip():
          return before_name_index + 1
      return len(skeleton_parameter)
  
  
  def parameter_list(elided_lines, start_position, end_position):
      """Generator for a function's parameters."""
      # Create new positions that omit the outer parenthesis of the parameters.
      start_position = Position(row=start_position.row, column=start_position.column + 1)
      end_position = Position(row=end_position.row, column=end_position.column - 1)
      single_line_view = SingleLineView(elided_lines, start_position, end_position)
      skeleton_parameters = create_skeleton_parameters(single_line_view.single_line)
      end_index = -1
  
      while True:
          # Find the end of the next parameter.
          start_index = end_index + 1
          end_index = skeleton_parameters.find(',', start_index)
  
          # No comma means that all parameters have been parsed.
          if end_index == -1:
              return
          row = single_line_view.convert_column_to_row(end_index)
  
          # Parse the parameter into a type and parameter name.
          skeleton_parameter = skeleton_parameters[start_index:end_index]
          name_offset = find_parameter_name_index(skeleton_parameter)
          parameter = single_line_view.single_line[start_index:end_index]
          yield Parameter(parameter, name_offset, row)
  
  
  class _FunctionState(object):
      """Tracks current function name and the number of lines in its body.
  
      Attributes:
        min_confidence: The minimum confidence level to use while checking style.
  
      """
  
      _NORMAL_TRIGGER = 250  # for --v=0, 500 for --v=1, etc.
      _TEST_TRIGGER = 400    # about 50% more than _NORMAL_TRIGGER.
  
      def __init__(self, min_confidence):
          self.min_confidence = min_confidence
          self.current_function = ''
          self.in_a_function = False
          self.lines_in_function = 0
          # Make sure these will not be mistaken for real positions (even when a
          # small amount is added to them).
          self.body_start_position = Position(-1000, 0)
          self.end_position = Position(-1000, 0)
  
      def begin(self, function_name, function_name_start_position, body_start_position, end_position,
                parameter_start_position, parameter_end_position, clean_lines):
          """Start analyzing function body.
  
          Args:
              function_name: The name of the function being tracked.
              function_name_start_position: Position in elided where the function name starts.
              body_start_position: Position in elided of the { or the ; for a prototype.
              end_position: Position in elided just after the final } (or ; is.
              parameter_start_position: Position in elided of the '(' for the parameters.
              parameter_end_position: Position in elided just after the ')' for the parameters.
              clean_lines: A CleansedLines instance containing the file.
          """
          self.in_a_function = True
          self.lines_in_function = -1  # Don't count the open brace line.
          self.current_function = function_name
          self.function_name_start_position = function_name_start_position
          self.body_start_position = body_start_position
          self.end_position = end_position
          self.is_declaration = clean_lines.elided[body_start_position.row][body_start_position.column] == ';'
          self.parameter_start_position = parameter_start_position
          self.parameter_end_position = parameter_end_position
          self.is_pure = False
          if self.is_declaration:
              characters_after_parameters = SingleLineView(
                  clean_lines.elided, parameter_end_position, body_start_position).single_line
              self.is_pure = bool(match(r'\s*=\s*0\s*', characters_after_parameters))
          self._clean_lines = clean_lines
          self._parameter_list = None
  
      def modifiers_and_return_type(self):
          """Returns the modifiers and the return type."""
          # Go backwards from where the function name is until we encounter one of several things:
          # ';' or '{' or '}' or 'private:', etc. or '#' or return Position(0, 0)
          elided = self._clean_lines.elided
          start_modifiers = _rfind_in_lines(r';|\{|\}|((private|public|protected):)|(#.*)',
                                            elided, self.parameter_start_position, Position(0, 0))
          return SingleLineView(elided, start_modifiers, self.function_name_start_position).single_line.strip()
  
      def parameter_list(self):
          if not self._parameter_list:
              # Store the final result as a tuple since that is immutable.
              self._parameter_list = tuple(parameter_list(self._clean_lines.elided,
                                                          self.parameter_start_position, self.parameter_end_position))
  
          return self._parameter_list
  
      def count(self, line_number):
          """Count line in current function body."""
          if self.in_a_function and line_number >= self.body_start_position.row:
              self.lines_in_function += 1
  
      def check(self, error, line_number):
          """Report if too many lines in function body.
  
          Args:
            error: The function to call with any errors found.
            line_number: The number of the line to check.
          """
          if match(r'T(EST|est)', self.current_function):
              base_trigger = self._TEST_TRIGGER
          else:
              base_trigger = self._NORMAL_TRIGGER
          trigger = base_trigger * 2 ** self.min_confidence
  
          if self.lines_in_function > trigger:
              error_level = int(math.log(self.lines_in_function / base_trigger, 2))
              # 50 => 0, 100 => 1, 200 => 2, 400 => 3, 800 => 4, 1600 => 5, ...
              if error_level > 5:
                  error_level = 5
              error(line_number, 'readability/fn_size', error_level,
                    'Small and focused functions are preferred:'
                    ' %s has %d non-comment lines'
                    ' (error triggered by exceeding %d lines).' % (
                        self.current_function, self.lines_in_function, trigger))
  
      def end(self):
          """Stop analyzing function body."""
          self.in_a_function = False
  
  
  class _IncludeError(Exception):
      """Indicates a problem with the include order in a file."""
      pass
  
  
  class FileInfo:
      """Provides utility functions for filenames.
  
      FileInfo provides easy access to the components of a file's path
      relative to the project root.
      """
  
      def __init__(self, filename):
          self._filename = filename
  
      def full_name(self):
          """Make Windows paths like Unix."""
          return os.path.abspath(self._filename).replace('\\', '/')
  
      def repository_name(self):
          """Full name after removing the local path to the repository.
  
          If we have a real absolute path name here we can try to do something smart:
          detecting the root of the checkout and truncating /path/to/checkout from
          the name so that we get header guards that don't include things like
          "C:\Documents and Settings\..." or "/home/username/..." in them and thus
          people on different computers who have checked the source out to different
          locations won't see bogus errors.
          """
          fullname = self.full_name()
  
          if os.path.exists(fullname):
              project_dir = os.path.dirname(fullname)
  
              if os.path.exists(os.path.join(project_dir, ".svn")):
                  # If there's a .svn file in the current directory, we
                  # recursively look up the directory tree for the top
                  # of the SVN checkout
                  root_dir = project_dir
                  one_up_dir = os.path.dirname(root_dir)
                  while os.path.exists(os.path.join(one_up_dir, ".svn")):
                      root_dir = os.path.dirname(root_dir)
                      one_up_dir = os.path.dirname(one_up_dir)
  
                  prefix = os.path.commonprefix([root_dir, project_dir])
                  return fullname[len(prefix) + 1:]
  
              # Not SVN? Try to find a git top level directory by
              # searching up from the current path.
              root_dir = os.path.dirname(fullname)
              while (root_dir != os.path.dirname(root_dir)
                     and not os.path.exists(os.path.join(root_dir, ".git"))):
                  root_dir = os.path.dirname(root_dir)
                  if os.path.exists(os.path.join(root_dir, ".git")):
                      prefix = os.path.commonprefix([root_dir, project_dir])
                      return fullname[len(prefix) + 1:]
  
          # Don't know what to do; header guard warnings may be wrong...
          return fullname
  
      def split(self):
          """Splits the file into the directory, basename, and extension.
  
          For 'chrome/browser/browser.cpp', Split() would
          return ('chrome/browser', 'browser', '.cpp')
  
          Returns:
            A tuple of (directory, basename, extension).
          """
  
          googlename = self.repository_name()
          project, rest = os.path.split(googlename)
          return (project,) + os.path.splitext(rest)
  
      def base_name(self):
          """File base name - text after the final slash, before the final period."""
          return self.split()[1]
  
      def extension(self):
          """File extension - text following the final period."""
          return self.split()[2]
  
      def no_extension(self):
          """File has no source file extension."""
          return '/'.join(self.split()[0:2])
  
      def is_source(self):
          """File has a source file extension."""
          return self.extension()[1:] in ('c', 'cc', 'cpp', 'cxx')
  
  
  # Matches standard C++ escape esequences per 2.13.2.3 of the C++ standard.
  _RE_PATTERN_CLEANSE_LINE_ESCAPES = re.compile(
      r'\\([abfnrtv?"\\\']|\d+|x[0-9a-fA-F]+)')
  # Matches strings.  Escape codes should already be removed by ESCAPES.
  _RE_PATTERN_CLEANSE_LINE_DOUBLE_QUOTES = re.compile(r'"[^"]*"')
  # Matches characters.  Escape codes should already be removed by ESCAPES.
  _RE_PATTERN_CLEANSE_LINE_SINGLE_QUOTES = re.compile(r"'.'")
  # Matches multiple strings (after the above cleanses) which can be concatenated.
  _RE_PATTERN_CLEANSE_MULTIPLE_STRINGS = re.compile(r'"("\s*")+"')
  
  # Matches multi-line C++ comments.
  # This RE is a little bit more complicated than one might expect, because we
  # have to take care of space removals tools so we can handle comments inside
  # statements better.
  # The current rule is: We only clear spaces from both sides when we're at the
  # end of the line. Otherwise, we try to remove spaces from the right side,
  # if this doesn't work we try on left side but only if there's a non-character
  # on the right.
  _RE_PATTERN_CLEANSE_LINE_C_COMMENTS = re.compile(
      r"""(\s*/\*.*\*/\s*$|
              /\*.*\*/\s+|
           \s+/\*.*\*/(?=\W)|
              /\*.*\*/)""", re.VERBOSE)
  
  
  def is_cpp_string(line):
      """Does line terminate so, that the next symbol is in string constant.
  
      This function does not consider single-line nor multi-line comments.
  
      Args:
        line: is a partial line of code starting from the 0..n.
  
      Returns:
        True, if next character appended to 'line' is inside a
        string constant.
      """
  
      line = line.replace(r'\\', 'XX')  # after this, \\" does not match to \"
      return ((line.count('"') - line.count(r'\"') - line.count("'\"'")) & 1) == 1
  
  
  def find_next_multi_line_comment_start(lines, line_index):
      """Find the beginning marker for a multiline comment."""
      while line_index < len(lines):
          if lines[line_index].strip().startswith('/*'):
              # Only return this marker if the comment goes beyond this line
              if lines[line_index].strip().find('*/', 2) < 0:
                  return line_index
          line_index += 1
      return len(lines)
  
  
  def find_next_multi_line_comment_end(lines, line_index):
      """We are inside a comment, find the end marker."""
      while line_index < len(lines):
          if lines[line_index].strip().endswith('*/'):
              return line_index
          line_index += 1
      return len(lines)
  
  
  def remove_multi_line_comments_from_range(lines, begin, end):
      """Clears a range of lines for multi-line comments."""
      # Having // dummy comments makes the lines non-empty, so we will not get
      # unnecessary blank line warnings later in the code.
      for i in range(begin, end):
          lines[i] = '// dummy'
  
  
  def remove_multi_line_comments(lines, error):
      """Removes multiline (c-style) comments from lines."""
      line_index = 0
      while line_index < len(lines):
          line_index_begin = find_next_multi_line_comment_start(lines, line_index)
          if line_index_begin >= len(lines):
              return
          line_index_end = find_next_multi_line_comment_end(lines, line_index_begin)
          if line_index_end >= len(lines):
              error(line_index_begin + 1, 'readability/multiline_comment', 5,
                    'Could not find end of multi-line comment')
              return
          remove_multi_line_comments_from_range(lines, line_index_begin, line_index_end + 1)
          line_index = line_index_end + 1
  
  
  def cleanse_comments(line):
      """Removes //-comments and single-line C-style /* */ comments.
  
      Args:
        line: A line of C++ source.
  
      Returns:
        The line with single-line comments removed.
      """
      comment_position = line.find('//')
      if comment_position != -1 and not is_cpp_string(line[:comment_position]):
          line = line[:comment_position]
      # get rid of /* ... */
      return _RE_PATTERN_CLEANSE_LINE_C_COMMENTS.sub('', line)
  
  
  class CleansedLines(object):
      """Holds 3 copies of all lines with different preprocessing applied to them.
  
      1) elided member contains lines without strings and comments,
      2) lines member contains lines without comments, and
      3) raw member contains all the lines without processing.
      All these three members are of <type 'list'>, and of the same length.
      """
  
      def __init__(self, lines):
          self.elided = []
          self.lines = []
          self.raw_lines = lines
          self._num_lines = len(lines)
          for line_number in range(len(lines)):
              self.lines.append(cleanse_comments(lines[line_number]))
              elided = self.collapse_strings(lines[line_number])
              self.elided.append(cleanse_comments(elided))
  
      def num_lines(self):
          """Returns the number of lines represented."""
          return self._num_lines
  
      @staticmethod
      def collapse_strings(elided):
          """Collapses strings and chars on a line to simple "" or '' blocks.
  
          We nix strings first so we're not fooled by text like '"http://"'
  
          Args:
            elided: The line being processed.
  
          Returns:
            The line with collapsed strings.
          """
          if not _RE_PATTERN_INCLUDE.match(elided):
              # Remove escaped characters first to make quote/single quote collapsing
              # basic.  Things that look like escaped characters shouldn't occur
              # outside of strings and chars.
              elided = _RE_PATTERN_CLEANSE_LINE_ESCAPES.sub('', elided)
              elided = _RE_PATTERN_CLEANSE_LINE_SINGLE_QUOTES.sub("''", elided)
              elided = _RE_PATTERN_CLEANSE_LINE_DOUBLE_QUOTES.sub('""', elided)
              elided = _RE_PATTERN_CLEANSE_MULTIPLE_STRINGS.sub('""', elided)
          return elided
  
  
  def close_expression(elided, position):
      """If input points to ( or { or [, finds the position that closes it.
  
      If elided[position.row][position.column] points to a '(' or '{' or '[',
      finds the line_number/pos that correspond to the closing of the expression.
  
       Args:
         elided: A CleansedLines.elided instance containing the file.
         position: The position of the opening item.
  
       Returns:
        The Position *past* the closing brace, or Position(len(elided), -1)
        if we never find a close. Note we ignore strings and comments when matching.
      """
      line = elided[position.row]
      start_character = line[position.column]
      if start_character == '(':
          enclosing_character_regex = r'[\(\)]'
      elif start_character == '[':
          enclosing_character_regex = r'[\[\]]'
      elif start_character == '{':
          enclosing_character_regex = r'[\{\}]'
      else:
          return Position(len(elided), -1)
  
      current_column = position.column + 1
      line_number = position.row
      net_open = 1
      for line in elided[position.row:]:
          line = line[current_column:]
  
          # Search the current line for opening and closing characters.
          while True:
              next_enclosing_character = search(enclosing_character_regex, line)
              # No more on this line.
              if not next_enclosing_character:
                  break
              current_column += next_enclosing_character.end(0)
              line = line[next_enclosing_character.end(0):]
              if next_enclosing_character.group(0) == start_character:
                  net_open += 1
              else:
                  net_open -= 1
                  if not net_open:
                      return Position(line_number, current_column)
  
          # Proceed to the next line.
          line_number += 1
          current_column = 0
  
      # The given item was not closed.
      return Position(len(elided), -1)
  
  
  def check_for_copyright(lines, error):
      """Logs an error if no Copyright message appears at the top of the file."""
  
      # We'll say it should occur by line 10. Don't forget there's a
      # dummy line at the front.
      for line in xrange(1, min(len(lines), 11)):
          if re.search(r'Copyright', lines[line], re.I):
              break
      else:                       # means no copyright line was found
          error(0, 'legal/copyright', 5,
                'No copyright message found.  '
                'You should have a line: "Copyright [year] <Copyright Owner>"')
  
  
  # TODO(jww) After the transition of Blink into the Chromium repo, this function
  # should be removed. This will strictly enforce Chromium-style header guards,
  # rather than allowing traditional WebKit header guards and Chromium-style
  # simultaneously.
  def get_legacy_header_guard_cpp_variable(filename):
      """Returns the CPP variable that should be used as a header guard.
  
      Args:
        filename: The name of a C++ header file.
  
      Returns:
        The CPP variable that should be used as a header guard in the
        named file.
  
      """
  
      # Restores original filename in case that style checker is invoked from Emacs's
      # flymake.
      filename = re.sub(r'_flymake\.h$', '.h', filename)
  
      standard_name = sub(r'[-.\s]', '_', os.path.basename(filename))
  
      # Files under WTF typically have header guards that start with WTF_.
      if '/wtf/' in filename:
          special_name = "WTF_" + standard_name
      else:
          special_name = standard_name
      return (special_name, standard_name)
  
  
  def get_header_guard_cpp_variable(filename):
      """Returns the CPP variable that should be used as a header guard in Chromium-style.
  
      Args:
        filename: The name of a C++ header file.
  
      Returns:
        The CPP variable that should be used as a header guard in the
        named file in Chromium-style.
  
      """
  
      # Restores original filename in case that style checker is invoked from Emacs's
      # flymake.
      filename = re.sub(r'_flymake\.h$', '.h', filename)
  
      # If it's a full path and starts with Source/, replace Source with blink
      # since that will be the new style directory.
      filename = sub(r'^Source\/', 'blink/', filename)
  
      standard_name = sub(r'[-.\s\/]', '_', filename).upper() + '_'
  
      return standard_name
  
  
  def check_for_header_guard(filename, lines, error):
      """Checks that the file contains a header guard.
  
      Logs an error if no #ifndef header guard is present.  For other
      headers, checks that the full pathname is used.
  
      Args:
        filename: The name of the C++ header file.
        lines: An array of strings, each representing a line of the file.
        error: The function to call with any errors found.
      """
  
      legacy_cpp_var = get_legacy_header_guard_cpp_variable(filename)
      cpp_var = get_header_guard_cpp_variable(filename)
  
      ifndef = None
      ifndef_line_number = 0
      define = None
      for line_number, line in enumerate(lines):
          line_split = line.split()
          if len(line_split) >= 2:
              # find the first occurrence of #ifndef and #define, save arg
              if not ifndef and line_split[0] == '#ifndef':
                  # set ifndef to the header guard presented on the #ifndef line.
                  ifndef = line_split[1]
                  ifndef_line_number = line_number
              if not define and line_split[0] == '#define':
                  define = line_split[1]
              if define and ifndef:
                  break
  
      if not ifndef or not define or ifndef != define:
          error(0, 'build/header_guard', 5,
                'No #ifndef header guard found, suggested CPP variable is: %s' %
                legacy_cpp_var[0])
          return
  
      # The guard should be File_h or, for Chromium style, BLINK_PATH_TO_FILE_H_.
      if ifndef not in legacy_cpp_var and ifndef != cpp_var:
          error(ifndef_line_number, 'build/header_guard', 5,
                '#ifndef header guard has wrong style, please use: %s' % legacy_cpp_var[0])
  
  
  def check_for_unicode_replacement_characters(lines, error):
      """Logs an error for each line containing Unicode replacement characters.
  
      These indicate that either the file contained invalid UTF-8 (likely)
      or Unicode replacement characters (which it shouldn't).  Note that
      it's possible for this to throw off line numbering if the invalid
      UTF-8 occurred adjacent to a newline.
  
      Args:
        lines: An array of strings, each representing a line of the file.
        error: The function to call with any errors found.
      """
      for line_number, line in enumerate(lines):
          if u'\ufffd' in line:
              error(line_number, 'readability/utf8', 5,
                    'Line contains invalid UTF-8 (or Unicode replacement character).')
  
  
  def check_for_new_line_at_eof(lines, error):
      """Logs an error if there is no newline char at the end of the file.
  
      Args:
        lines: An array of strings, each representing a line of the file.
        error: The function to call with any errors found.
      """
  
      # The array lines() was created by adding two newlines to the
      # original file (go figure), then splitting on \n.
      # To verify that the file ends in \n, we just have to make sure the
      # last-but-two element of lines() exists and is empty.
      if len(lines) < 3 or lines[-2]:
          error(len(lines) - 2, 'whitespace/ending_newline', 5,
                'Could not find a newline character at the end of the file.')
  
  
  def check_for_multiline_comments_and_strings(clean_lines, line_number, error):
      """Logs an error if we see /* ... */ or "..." that extend past one line.
  
      /* ... */ comments are legit inside macros, for one line.
      Otherwise, we prefer // comments, so it's ok to warn about the
      other.  Likewise, it's ok for strings to extend across multiple
      lines, as long as a line continuation character (backslash)
      terminates each line. Although not currently prohibited by the C++
      style guide, it's ugly and unnecessary. We don't do well with either
      in this lint program, so we warn about both.
  
      Args:
        clean_lines: A CleansedLines instance containing the file.
        line_number: The number of the line to check.
        error: The function to call with any errors found.
      """
      line = clean_lines.elided[line_number]
  
      # Remove all \\ (escaped backslashes) from the line. They are OK, and the
      # second (escaped) slash may trigger later \" detection erroneously.
      line = line.replace('\\\\', '')
  
      if line.count('/*') > line.count('*/'):
          error(line_number, 'readability/multiline_comment', 5,
                'Complex multi-line /*...*/-style comment found. '
                'Lint may give bogus warnings.  '
                'Consider replacing these with //-style comments, '
                'with #if 0...#endif, '
                'or with more clearly structured multi-line comments.')
  
      if (line.count('"') - line.count('\\"')) % 2:
          error(line_number, 'readability/multiline_string', 5,
                'Multi-line string ("...") found.  This lint script doesn\'t '
                'do well with such strings, and may give bogus warnings.  They\'re '
                'ugly and unnecessary, and you should use concatenation instead".')
  
  
  _THREADING_LIST = (
      ('asctime(', 'asctime_r('),
      ('ctime(', 'ctime_r('),
      ('getgrgid(', 'getgrgid_r('),
      ('getgrnam(', 'getgrnam_r('),
      ('getlogin(', 'getlogin_r('),
      ('getpwnam(', 'getpwnam_r('),
      ('getpwuid(', 'getpwuid_r('),
      ('gmtime(', 'gmtime_r('),
      ('localtime(', 'localtime_r('),
      ('rand(', 'rand_r('),
      ('readdir(', 'readdir_r('),
      ('strtok(', 'strtok_r('),
      ('ttyname(', 'ttyname_r('),
  )
  
  
  def check_posix_threading(clean_lines, line_number, error):
      """Checks for calls to thread-unsafe functions.
  
      Much code has been originally written without consideration of
      multi-threading. Also, engineers are relying on their old experience;
      they have learned posix before threading extensions were added. These
      tests guide the engineers to use thread-safe functions (when using
      posix directly).
  
      Args:
        clean_lines: A CleansedLines instance containing the file.
        line_number: The number of the line to check.
        error: The function to call with any errors found.
      """
      line = clean_lines.elided[line_number]
      for single_thread_function, multithread_safe_function in _THREADING_LIST:
          index = line.find(single_thread_function)
          # Comparisons made explicit for clarity
          if index >= 0 and (index == 0 or (not line[index - 1].isalnum()
                                            and line[index - 1] not in ('_', '.', '>'))):
              error(line_number, 'runtime/threadsafe_fn', 2,
                    'Consider using ' + multithread_safe_function +
                    '...) instead of ' + single_thread_function +
                    '...) for improved thread safety.')
  
  
  # Matches invalid increment: *count++, which moves pointer instead of
  # incrementing a value.
  _RE_PATTERN_INVALID_INCREMENT = re.compile(
      r'^\s*\*\w+(\+\+|--);')
  
  
  def check_invalid_increment(clean_lines, line_number, error):
      """Checks for invalid increment *count++.
  
      For example following function:
      void increment_counter(int* count) {
          *count++;
      }
      is invalid, because it effectively does count++, moving pointer, and should
      be replaced with ++*count, (*count)++ or *count += 1.
  
      Args:
        clean_lines: A CleansedLines instance containing the file.
        line_number: The number of the line to check.
        error: The function to call with any errors found.
      """
      line = clean_lines.elided[line_number]
      if _RE_PATTERN_INVALID_INCREMENT.match(line):
          error(line_number, 'runtime/invalid_increment', 5,
                'Changing pointer instead of value (or unused value of operator*).')
  
  
  class _ClassInfo(object):
      """Stores information about a class."""
  
      def __init__(self, name, line_number):
          self.name = name
          self.line_number = line_number
          self.seen_open_brace = False
          self.is_derived = False
          self.virtual_method_line_number = None
          self.has_virtual_destructor = False
          self.brace_depth = 0
          self.unsigned_bitfields = []
          self.bool_bitfields = []
  
  
  class _ClassState(object):
      """Holds the current state of the parse relating to class declarations.
  
      It maintains a stack of _ClassInfos representing the parser's guess
      as to the current nesting of class declarations. The innermost class
      is at the top (back) of the stack. Typically, the stack will either
      be empty or have exactly one entry.
      """
  
      def __init__(self):
          self.classinfo_stack = []
  
      def check_finished(self, error):
          """Checks that all classes have been completely parsed.
  
          Call this when all lines in a file have been processed.
          Args:
            error: The function to call with any errors found.
          """
          if self.classinfo_stack:
              # Note: This test can result in false positives if #ifdef constructs
              # get in the way of brace matching. See the testBuildClass test in
              # cpp_style_unittest.py for an example of this.
              error(self.classinfo_stack[0].line_number, 'build/class', 5,
                    'Failed to find complete declaration of class %s' %
                    self.classinfo_stack[0].name)
  
  
  class _FileState(object):
  
      def __init__(self, clean_lines, file_extension):
          self._did_inside_namespace_indent_warning = False
          self._clean_lines = clean_lines
          if file_extension in ['m', 'mm']:
              self._is_objective_c = True
              self._is_c = False
          elif file_extension == 'h':
              # In the case of header files, it is unknown if the file
              # is c / objective c or not, so set this value to None and then
              # if it is requested, use heuristics to guess the value.
              self._is_objective_c = None
              self._is_c = None
          elif file_extension == 'c':
              self._is_c = True
              self._is_objective_c = False
          else:
              self._is_objective_c = False
              self._is_c = False
  
      def set_did_inside_namespace_indent_warning(self):
          self._did_inside_namespace_indent_warning = True
  
      def did_inside_namespace_indent_warning(self):
          return self._did_inside_namespace_indent_warning
  
      def is_objective_c(self):
          if self._is_objective_c is None:
              for line in self._clean_lines.elided:
                  # Starting with @ or #import seem like the best indications
                  # that we have an Objective C file.
                  if line.startswith("@") or line.startswith("#import"):
                      self._is_objective_c = True
                      break
              else:
                  self._is_objective_c = False
          return self._is_objective_c
  
      def is_c(self):
          if self._is_c is None:
              for line in self._clean_lines.lines:
                  # if extern "C" is found, then it is a good indication
                  # that we have a C header file.
                  if line.startswith('extern "C"'):
                      self._is_c = True
                      break
              else:
                  self._is_c = False
          return self._is_c
  
      def is_c_or_objective_c(self):
          """Return whether the file extension corresponds to C or Objective-C."""
          return self.is_c() or self.is_objective_c()
  
  
  class _EnumState(object):
      """Maintains whether currently in an enum declaration, and checks whether
      enum declarations follow the style guide.
      """
  
      def __init__(self):
          self.in_enum_decl = False
          self.is_webidl_enum = False
  
      def process_clean_line(self, line):
          # FIXME: The regular expressions for expr_all_uppercase and expr_enum_end only accept integers
          # and identifiers for the value of the enumerator, but do not accept any other constant
          # expressions. However, this is sufficient for now (11/27/2012).
          expr_all_uppercase = r'\s*[A-Z0-9_]+\s*(?:=\s*[a-zA-Z0-9]+\s*)?,?\s*$'
          expr_starts_lowercase = r'\s*[a-jl-z]|k[a-z]'
          expr_enum_end = r'}\s*(?:[a-zA-Z0-9]+\s*(?:=\s*[a-zA-Z0-9]+)?)?\s*;\s*'
          expr_enum_start = r'\s*enum(?:\s+[a-zA-Z0-9]+)?\s*\{?\s*'
          if self.in_enum_decl:
              if match(r'\s*' + expr_enum_end + r'$', line):
                  self.in_enum_decl = False
                  self.is_webidl_enum = False
              elif match(expr_all_uppercase, line):
                  return self.is_webidl_enum
              elif match(expr_starts_lowercase, line):
                  return False
          else:
              matched = match(expr_enum_start + r'$', line)
              if matched:
                  self.in_enum_decl = True
              else:
                  matched = match(expr_enum_start + r'(?P<members>.*)' + expr_enum_end + r'$', line)
                  if matched:
                      members = matched.group('members').split(',')
                      found_invalid_member = False
                      for member in members:
                          if match(expr_all_uppercase, member):
                              found_invalid_member = not self.is_webidl_enum
                          if match(expr_starts_lowercase, member):
                              found_invalid_member = True
                          if found_invalid_member:
                              self.is_webidl_enum = False
                              return False
                      return True
          return True
  
  
  def check_for_non_standard_constructs(clean_lines, line_number,
                                        class_state, error):
      """Logs an error if we see certain non-ANSI constructs ignored by gcc-2.
  
      Complain about several constructs which gcc-2 accepts, but which are
      not standard C++.  Warning about these in lint is one way to ease the
      transition to new compilers.
      - put storage class first (e.g. "static const" instead of "const static").
      - "%lld" instead of %qd" in printf-type functions.
      - "%1$d" is non-standard in printf-type functions.
      - "\%" is an undefined character escape sequence.
      - text after #endif is not allowed.
      - invalid inner-style forward declaration.
      - >? and <? operators, and their >?= and <?= cousins.
      - classes with virtual methods need virtual destructors (compiler warning
          available, but not turned on yet.)
  
      Additionally, check for constructor/destructor style violations as it
      is very convenient to do so while checking for gcc-2 compliance.
  
      Args:
        clean_lines: A CleansedLines instance containing the file.
        line_number: The number of the line to check.
        class_state: A _ClassState instance which maintains information about
                     the current stack of nested class declarations being parsed.
        error: A callable to which errors are reported, which takes parameters:
               line number, error level, and message
      """
  
      # Remove comments from the line, but leave in strings for now.
      line = clean_lines.lines[line_number]
  
      if search(r'printf\s*\(.*".*%[-+ ]?\d*q', line):
          error(line_number, 'runtime/printf_format', 3,
                '%q in format strings is deprecated.  Use %ll instead.')
  
      if search(r'printf\s*\(.*".*%\d+\$', line):
          error(line_number, 'runtime/printf_format', 2,
                '%N$ formats are unconventional.  Try rewriting to avoid them.')
  
      # Remove escaped backslashes before looking for undefined escapes.
      line = line.replace('\\\\', '')
  
      if search(r'("|\').*\\(%|\[|\(|{)', line):
          error(line_number, 'build/printf_format', 3,
                '%, [, (, and { are undefined character escapes.  Unescape them.')
  
      # For the rest, work with both comments and strings removed.
      line = clean_lines.elided[line_number]
  
      if search(r'\b(const|volatile|void|char|short|int|long'
                r'|float|double|signed|unsigned'
                r'|schar|u?int8|u?int16|u?int32|u?int64)'
                r'\s+(auto|register|static|extern|typedef)\b',
                line):
          error(line_number, 'build/storage_class', 5,
                'Storage class (static, extern, typedef, etc) should be first.')
  
      if match(r'\s*#\s*endif\s*[^/\s]+', line):
          error(line_number, 'build/endif_comment', 5,
                'Uncommented text after #endif is non-standard.  Use a comment.')
  
      if match(r'\s*class\s+(\w+\s*::\s*)+\w+\s*;', line):
          error(line_number, 'build/forward_decl', 5,
                'Inner-style forward declarations are invalid.  Remove this line.')
  
      if search(r'(\w+|[+-]?\d+(\.\d*)?)\s*(<|>)\?=?\s*(\w+|[+-]?\d+)(\.\d*)?', line):
          error(line_number, 'build/deprecated', 3,
                '>? and <? (max and min) operators are non-standard and deprecated.')
  
      if search(r'\w+<.*<.*>\s+>', line):
          error(line_number, 'readability/templatebrackets', 3,
                'Use >> for ending template instead of > >.')
  
      if search(r'\w+<\s+::\w+>', line):
          error(line_number, 'readability/templatebrackets', 3,
                'Use <:: for template start instead of < ::.')
  
      # Track class entry and exit, and attempt to find cases within the
      # class declaration that don't meet the C++ style
      # guidelines. Tracking is very dependent on the code matching Google
      # style guidelines, but it seems to perform well enough in testing
      # to be a worthwhile addition to the checks.
      classinfo_stack = class_state.classinfo_stack
      # Look for a class declaration
      class_decl_match = match(
          r'\s*(template\s*<[\w\s<>,:]*>\s*)?(class|struct)\s+(\w+(::\w+)*)', line)
      if class_decl_match:
          classinfo_stack.append(_ClassInfo(class_decl_match.group(3), line_number))
  
      # Everything else in this function uses the top of the stack if it's
      # not empty.
      if not classinfo_stack:
          return
  
      classinfo = classinfo_stack[-1]
  
      # If the opening brace hasn't been seen look for it and also
      # parent class declarations.
      if not classinfo.seen_open_brace:
          # If the line has a ';' in it, assume it's a forward declaration or
          # a single-line class declaration, which we won't process.
          if ';' in line:
              classinfo_stack.pop()
              return
          classinfo.seen_open_brace = ('{' in line)
          # Look for a bare ':'
          if search('(^|[^:]):($|[^:])', line):
              classinfo.is_derived = True
          if not classinfo.seen_open_brace:
              return  # Everything else in this function is for after open brace
  
      # The class may have been declared with namespace or classname qualifiers.
      # The constructor and destructor will not have those qualifiers.
      base_classname = classinfo.name.split('::')[-1]
  
      # Look for single-argument constructors that aren't marked explicit.
      # Technically a valid construct, but against style.
      args = match(r'(?<!explicit)\s+%s\s*\(([^,()]+)\)'
                   % re.escape(base_classname),
                   line)
      if (args
          and args.group(1) != 'void'
          and not match(r'(const\s+)?%s\s*&' % re.escape(base_classname),
                        args.group(1).strip())):
          error(line_number, 'runtime/explicit', 5,
                'Single-argument constructors should be marked explicit.')
  
      # Look for methods declared virtual.
      if search(r'\bvirtual\b', line):
          classinfo.virtual_method_line_number = line_number
          # Only look for a destructor declaration on the same line. It would
          # be extremely unlikely for the destructor declaration to occupy
          # more than one line.
          if search(r'~%s\s*\(' % base_classname, line):
              classinfo.has_virtual_destructor = True
  
      # Look for class end.
      brace_depth = classinfo.brace_depth
      brace_depth = brace_depth + line.count('{') - line.count('}')
      if brace_depth <= 0:
          classinfo = classinfo_stack.pop()
          # Try to detect missing virtual destructor declarations.
          # For now, only warn if a non-derived class with virtual methods lacks
          # a virtual destructor. This is to make it less likely that people will
          # declare derived virtual destructors without declaring the base
          # destructor virtual.
          if ((classinfo.virtual_method_line_number is not None)
                  and (not classinfo.has_virtual_destructor)
                  and (not classinfo.is_derived)):  # Only warn for base classes
              error(classinfo.line_number, 'runtime/virtual', 4,
                    'The class %s probably needs a virtual destructor due to '
                    'having virtual method(s), one declared at line %d.'
                    % (classinfo.name, classinfo.virtual_method_line_number))
          # Look for mixed bool and unsigned bitfields.
          if classinfo.bool_bitfields and classinfo.unsigned_bitfields:
              bool_list = ', '.join(classinfo.bool_bitfields)
              unsigned_list = ', '.join(classinfo.unsigned_bitfields)
              error(classinfo.line_number, 'runtime/bitfields', 5,
                    'The class %s contains mixed unsigned and bool bitfields, '
                    'which will pack into separate words on the MSVC compiler.\n'
                    'Bool bitfields are [%s].\nUnsigned bitfields are [%s].\n'
                    'Consider converting bool bitfields to unsigned.'
                    % (classinfo.name, bool_list, unsigned_list))
      else:
          classinfo.brace_depth = brace_depth
  
      well_typed_bitfield = False
      # Look for bool <name> : 1 declarations.
      args = search(r'\bbool\s+(\S*)\s*:\s*\d+\s*;', line)
      if args:
          classinfo.bool_bitfields.append('%d: %s' % (line_number, args.group(1)))
          well_typed_bitfield = True
  
      # Look for unsigned <name> : n declarations.
      args = search(r'\bunsigned\s+(?:int\s+)?(\S+)\s*:\s*\d+\s*;', line)
      if args:
          classinfo.unsigned_bitfields.append('%d: %s' % (line_number, args.group(1)))
          well_typed_bitfield = True
  
      # Look for other bitfield declarations. We don't care about those in
      # size-matching structs.
      if not (well_typed_bitfield or classinfo.name.startswith('SameSizeAs') or
              classinfo.name.startswith('Expected')):
          args = match(r'\s*(\S+)\s+(\S+)\s*:\s*\d+\s*;', line)
          if args:
              error(line_number, 'runtime/bitfields', 4,
                    'Member %s of class %s defined as a bitfield of type %s. '
                    'Please declare all bitfields as unsigned.'
                    % (args.group(2), classinfo.name, args.group(1)))
  
  
  def check_spacing_for_function_call(line, line_number, error):
      """Checks for the correctness of various spacing around function calls.
  
      Args:
        line: The text of the line to check.
        line_number: The number of the line to check.
        error: The function to call with any errors found.
      """
  
      # Since function calls often occur inside if/for/foreach/while/switch
      # expressions - which have their own, more liberal conventions - we
      # first see if we should be looking inside such an expression for a
      # function call, to which we can apply more strict standards.
      function_call = line    # if there's no control flow construct, look at whole line
      for pattern in (r'\bif\s*\((.*)\)\s*{',
                      r'\bfor\s*\((.*)\)\s*{',
                      r'\bforeach\s*\((.*)\)\s*{',
                      r'\bwhile\s*\((.*)\)\s*[{;]',
                      r'\bswitch\s*\((.*)\)\s*{'):
          matched = search(pattern, line)
          if matched:
              function_call = matched.group(1)    # look inside the parens for function calls
              break
  
      # Except in if/for/foreach/while/switch, there should never be space
      # immediately inside parens (eg "f( 3, 4 )").  We make an exception
      # for nested parens ( (a+b) + c ).  Likewise, there should never be
      # a space before a ( when it's a function argument.  I assume it's a
      # function argument when the char before the whitespace is legal in
      # a function name (alnum + _) and we're not starting a macro. Also ignore
      # pointers and references to arrays and functions coz they're too tricky:
      # we use a very simple way to recognize these:
      # " (something)(maybe-something)" or
      # " (something)(maybe-something," or
      # " (something)[something]"
      # Note that we assume the contents of [] to be short enough that
      # they'll never need to wrap.
      if (  # Ignore control structures.
              not search(r'\b(if|for|foreach|while|switch|return|new|delete)\b', function_call)
              # Ignore pointers/references to functions.
              and not search(r' \([^)]+\)\([^)]*(\)|,$)', function_call)
              # Ignore pointers/references to arrays.
              and not search(r' \([^)]+\)\[[^\]]+\]', function_call)):
          if search(r'\w\s*\([ \t](?!\s*\\$)', function_call):      # a ( used for a fn call
              error(line_number, 'whitespace/parens', 4,
                    'Extra space after ( in function call')
          elif search(r'\([ \t]+(?!(\s*\\)|\()', function_call):
              error(line_number, 'whitespace/parens', 2,
                    'Extra space after (')
          if (search(r'\w\s+\(', function_call)
                  and not match(r'\s*(#|typedef)', function_call)):
              error(line_number, 'whitespace/parens', 4,
                    'Extra space before ( in function call')
          # If the ) is followed only by a newline or a { + newline, assume it's
          # part of a control statement (if/while/etc), and don't complain
          if search(r'[^)\s]\s+\)(?!\s*$|{\s*$)', function_call):
              error(line_number, 'whitespace/parens', 2,
                    'Extra space before )')
  
  
  def is_blank_line(line):
      """Returns true if the given line is blank.
  
      We consider a line to be blank if the line is empty or consists of
      only white spaces.
  
      Args:
        line: A line of a string.
  
      Returns:
        True, if the given line is blank.
      """
      return not line or line.isspace()
  
  
  def detect_functions(clean_lines, line_number, function_state, error):
      """Finds where functions start and end.
  
      Uses a simplistic algorithm assuming other style guidelines
      (especially spacing) are followed.
      Trivial bodies are unchecked, so constructors with huge initializer lists
      may be missed.
  
      Args:
        clean_lines: A CleansedLines instance containing the file.
        line_number: The number of the line to check.
        function_state: Current function name and lines in body so far.
        error: The function to call with any errors found.
      """
      # Are we now past the end of a function?
      if function_state.end_position.row + 1 == line_number:
          function_state.end()
  
      # If we're in a function, don't try to detect a new one.
      if function_state.in_a_function:
          return
  
      lines = clean_lines.lines
      line = lines[line_number]
      raw = clean_lines.raw_lines
      raw_line = raw[line_number]
  
      # Lines ending with a \ indicate a macro. Don't try to check them.
      if raw_line.endswith('\\'):
          return
  
      regexp = r'\s*(\w(\w|::|\*|\&|\s|<|>|,|~|(operator\s*(/|-|=|!|\+)+))*)\('  # decls * & space::name( ...
      match_result = match(regexp, line)
      if not match_result:
          return
  
      # If the name is all caps and underscores, figure it's a macro and
      # ignore it, unless it's TEST or TEST_F.
      function_name = match_result.group(1).split()[-1]
      if function_name != 'TEST' and function_name != 'TEST_F' and match(r'[A-Z_]+$', function_name):
          return
  
      joined_line = ''
      for start_line_number in xrange(line_number, clean_lines.num_lines()):
          start_line = clean_lines.elided[start_line_number]
          joined_line += ' ' + start_line.lstrip()
          body_match = search(r'{|;', start_line)
          if body_match:
              body_start_position = Position(start_line_number, body_match.start(0))
  
              # Replace template constructs with _ so that no spaces remain in the function name,
              # while keeping the column numbers of other characters the same as "line".
              line_with_no_templates = iteratively_replace_matches_with_char(r'<[^<>]*>', '_', line)
              match_function = search(r'((\w|:|<|>|,|~|(operator\s*(/|-|=|!|\+)+))*)\(', line_with_no_templates)
              if not match_function:
                  return  # The '(' must have been inside of a template.
  
              # Use the column numbers from the modified line to find the
              # function name in the original line.
              function = line[match_function.start(1):match_function.end(1)]
              function_name_start_position = Position(line_number, match_function.start(1))
  
              if match(r'TEST', function):    # Handle TEST... macros
                  parameter_regexp = search(r'(\(.*\))', joined_line)
                  if parameter_regexp:             # Ignore bad syntax
                      function += parameter_regexp.group(1)
              else:
                  function += '()'
  
              parameter_start_position = Position(line_number, match_function.end(1))
              parameter_end_position = close_expression(clean_lines.elided, parameter_start_position)
              if parameter_end_position.row == len(clean_lines.elided):
                  # No end was found.
                  return
  
              if start_line[body_start_position.column] == ';':
                  end_position = Position(body_start_position.row, body_start_position.column + 1)
              else:
                  end_position = close_expression(clean_lines.elided, body_start_position)
  
              # Check for nonsensical positions. (This happens in test cases which check code snippets.)
              if parameter_end_position > body_start_position:
                  return
  
              function_state.begin(function, function_name_start_position, body_start_position, end_position,
                                   parameter_start_position, parameter_end_position, clean_lines)
              return
  
      # No body for the function (or evidence of a non-function) was found.
      error(line_number, 'readability/fn_size', 5,
            'Lint failed to find start of function body.')
  
  
  def check_for_function_lengths(clean_lines, line_number, function_state, error):
      """Reports for long function bodies.
  
      For an overview why this is done, see:
      http://google-styleguide.googlecode.com/svn/trunk/cppguide.xml#Write_Short_Functions
  
      Blank/comment lines are not counted so as to avoid encouraging the removal
      of vertical space and comments just to get through a lint check.
      NOLINT *on the last line of a function* disables this check.
  
      Args:
        clean_lines: A CleansedLines instance containing the file.
        line_number: The number of the line to check.
        function_state: Current function name and lines in body so far.
        error: The function to call with any errors found.
      """
      lines = clean_lines.lines
      line = lines[line_number]
      raw = clean_lines.raw_lines
      raw_line = raw[line_number]
  
      if function_state.end_position.row == line_number:  # last line
          if not search(r'\bNOLINT\b', raw_line):
              function_state.check(error, line_number)
      elif not match(r'^\s*$', line):
          function_state.count(line_number)  # Count non-blank/non-comment lines.
  
  
  def _check_parameter_name_against_text(parameter, text, error):
      """Checks to see if the parameter name is contained within the text.
  
      Return false if the check failed (i.e. an error was produced).
      """
  
      # Treat 'lower with underscores' as a canonical form because it is
      # case insensitive while still retaining word breaks. (This ensures that
      # 'elate' doesn't look like it is duplicating of 'NateLate'.)
      canonical_parameter_name = parameter.lower_with_underscores_name()
  
      # Appends "object" to all text to catch variables that did the same (but only
      # do this when the parameter name is more than a single character to avoid
      # flagging 'b' which may be an ok variable when used in an rgba function).
      if len(canonical_parameter_name) > 1:
          text = sub(r'(\w)\b', r'\1Object', text)
      canonical_text = _convert_to_lower_with_underscores(text)
  
      # Used to detect cases like ec for ExceptionCode.
      acronym = _create_acronym(text).lower()
      if canonical_text.find(canonical_parameter_name) != -1 or acronym.find(canonical_parameter_name) != -1:
          error(parameter.row, 'readability/parameter_name', 5,
                'The parameter name "%s" adds no information, so it should be removed.' % parameter.name)
          return False
      return True
  
  
  def check_function_definition_and_pass_ptr(type_text, row, location_description, error):
      """Check that function definitions for use Pass*Ptr instead of *Ptr.
  
      Args:
         type_text: A string containing the type. (For return values, it may contain more than the type.)
         row: The row number of the type.
         location_description: Used to indicate where the type is. This is either 'parameter' or 'return'.
         error: The function to call with any errors found.
      """
      match_ref_or_own_ptr = '(?=\W|^)(Ref|Own)Ptr(WillBeRawPtr)?(?=\W)'
      exceptions = '(?:&|\*|\*\s*=\s*(0|nullptr))$'
      bad_type_usage = search(match_ref_or_own_ptr, type_text)
      exception_usage = search(exceptions, type_text)
      if not bad_type_usage or exception_usage:
          return
      type_name = bad_type_usage.group(0)
      error(row, 'readability/pass_ptr', 5,
            'The %s type should use Pass%s instead of %s.' % (location_description, type_name, type_name))
  
  
  def check_function_definition(filename, file_extension, clean_lines, line_number, function_state, error):
      """Check that function definitions for style issues.
  
      Specifically, check that parameter names in declarations add information.
  
      Args:
         filename: Filename of the file that is being processed.
         file_extension: The current file extension, without the leading dot.
         clean_lines: A CleansedLines instance containing the file.
         line_number: The number of the line to check.
         function_state: Current function name and lines in body so far.
         error: The function to call with any errors found.
      """
      if line_number != function_state.body_start_position.row:
          return
  
      modifiers_and_return_type = function_state.modifiers_and_return_type()
      if filename.find('/chromium/') != -1 and search(r'\bWEBKIT_EXPORT\b', modifiers_and_return_type):
          if filename.find('/chromium/public/') == -1 and filename.find('/chromium/tests/') == - \
                  1 and filename.find('chromium/platform') == -1:
              error(function_state.function_name_start_position.row, 'readability/webkit_export', 5,
                    'WEBKIT_EXPORT should only appear in the chromium public (or tests) directory.')
          elif not file_extension == "h":
              error(function_state.function_name_start_position.row, 'readability/webkit_export', 5,
                    'WEBKIT_EXPORT should only be used in header files.')
          elif not function_state.is_declaration or search(r'\binline\b', modifiers_and_return_type):
              error(function_state.function_name_start_position.row, 'readability/webkit_export', 5,
                    'WEBKIT_EXPORT should not be used on a function with a body.')
          elif function_state.is_pure:
              error(function_state.function_name_start_position.row, 'readability/webkit_export', 5,
                    'WEBKIT_EXPORT should not be used with a pure virtual function.')
  
      check_function_definition_and_pass_ptr(
          modifiers_and_return_type, function_state.function_name_start_position.row, 'return', error)
  
      parameter_list = function_state.parameter_list()
      for parameter in parameter_list:
          check_function_definition_and_pass_ptr(parameter.type, parameter.row, 'parameter', error)
  
          # Do checks specific to function declarations and parameter names.
          if not function_state.is_declaration or not parameter.name:
              continue
  
          # Check the parameter name against the function name for single parameter set functions.
          if len(parameter_list) == 1 and match('set[A-Z]', function_state.current_function):
              trimmed_function_name = function_state.current_function[len('set'):]
              if not _check_parameter_name_against_text(parameter, trimmed_function_name, error):
                  continue  # Since an error was noted for this name, move to the next parameter.
  
          # Check the parameter name against the type.
          if not _check_parameter_name_against_text(parameter, parameter.type, error):
              continue  # Since an error was noted for this name, move to the next parameter.
  
  
  def check_pass_ptr_usage(clean_lines, line_number, function_state, error):
      """Check for proper usage of Pass*Ptr.
  
      Currently this is limited to detecting declarations of Pass*Ptr
      variables inside of functions.
  
      Args:
        clean_lines: A CleansedLines instance containing the file.
        line_number: The number of the line to check.
        function_state: Current function name and lines in body so far.
        error: The function to call with any errors found.
      """
      if not function_state.in_a_function:
          return
  
      lines = clean_lines.lines
      line = lines[line_number]
      if line_number > function_state.body_start_position.row:
          matched_pass_ptr = match(r'^\s*Pass([A-Z][A-Za-z]*)Ptr<', line)
          if matched_pass_ptr:
              type_name = 'Pass%sPtr' % matched_pass_ptr.group(1)
              error(line_number, 'readability/pass_ptr', 5,
                    'Local variables should never be %s (see '
                    'http://webkit.org/coding/RefPtr.html).' % type_name)
  
  
  def check_for_leaky_patterns(clean_lines, line_number, function_state, error):
      """Check for constructs known to be leak prone.
      Args:
        clean_lines: A CleansedLines instance containing the file.
        line_number: The number of the line to check.
        function_state: Current function name and lines in body so far.
        error: The function to call with any errors found.
      """
      lines = clean_lines.lines
      line = lines[line_number]
  
      matched_get_dc = search(r'\b(?P<function_name>GetDC(Ex)?)\s*\(', line)
      if matched_get_dc:
          error(line_number, 'runtime/leaky_pattern', 5,
                'Use the class HWndDC instead of calling %s to avoid potential '
                'memory leaks.' % matched_get_dc.group('function_name'))
  
      matched_create_dc = search(r'\b(?P<function_name>Create(Compatible)?DC)\s*\(', line)
      matched_own_dc = search(r'\badoptPtr\b', line)
      if matched_create_dc and not matched_own_dc:
          error(line_number, 'runtime/leaky_pattern', 5,
                'Use adoptPtr and OwnPtr<HDC> when calling %s to avoid potential '
                'memory leaks.' % matched_create_dc.group('function_name'))
  
  
  def check_spacing(file_extension, clean_lines, line_number, error):
      """Checks for the correctness of various spacing issues in the code.
  
      Things we check for: spaces around operators, spaces after
      if/for/while/switch, no spaces around parens in function calls, two
      spaces between code and comment, don't start a block with a blank
      line, don't end a function with a blank line, don't have too many
      blank lines in a row.
  
      Args:
        file_extension: The current file extension, without the leading dot.
        clean_lines: A CleansedLines instance containing the file.
        line_number: The number of the line to check.
        error: The function to call with any errors found.
      """
  
      raw = clean_lines.raw_lines
      line = raw[line_number]
  
      # Before nixing comments, check if the line is blank for no good
      # reason.  This includes the first line after a block is opened, and
      # blank lines at the end of a function (ie, right before a line like '}').
      if is_blank_line(line):
          elided = clean_lines.elided
          previous_line = elided[line_number - 1]
          previous_brace = previous_line.rfind('{')
          # FIXME: Don't complain if line before blank line, and line after,
          #        both start with alnums and are indented the same amount.
          #        This ignores whitespace at the start of a namespace block
          #        because those are not usually indented.
          if (previous_brace != -1 and previous_line[previous_brace:].find('}') == -1
                  and previous_line[:previous_brace].find('namespace') == -1):
              # OK, we have a blank line at the start of a code block.  Before we
              # complain, we check if it is an exception to the rule: The previous
              # non-empty line has the parameters of a function header that are indented
              # 4 spaces (because they did not fit in a 80 column line when placed on
              # the same line as the function name).  We also check for the case where
              # the previous line is indented 6 spaces, which may happen when the
              # initializers of a constructor do not fit into a 80 column line.
              exception = False
              if match(r' {6}\w', previous_line):  # Initializer list?
                  # We are looking for the opening column of initializer list, which
                  # should be indented 4 spaces to cause 6 space indentation afterwards.
                  search_position = line_number - 2
                  while (search_position >= 0
                         and match(r' {6}\w', elided[search_position])):
                      search_position -= 1
                  exception = (search_position >= 0
                               and elided[search_position][:5] == '    :')
              else:
                  # Search for the function arguments or an initializer list.  We use a
                  # simple heuristic here: If the line is indented 4 spaces; and we have a
                  # closing paren, without the opening paren, followed by an opening brace
                  # or colon (for initializer lists) we assume that it is the last line of
                  # a function header.  If we have a colon indented 4 spaces, it is an
                  # initializer list.
                  exception = (match(r' {4}\w[^\(]*\)\s*(const\s*)?(\{\s*$|:)',
                                     previous_line)
                               or match(r' {4}:', previous_line))
  
              if not exception:
                  error(line_number, 'whitespace/blank_line', 2,
                        'Blank line at the start of a code block.  Is this needed?')
          # This doesn't ignore whitespace at the end of a namespace block
          # because that is too hard without pairing open/close braces;
          # however, a special exception is made for namespace closing
          # brackets which have a comment containing "namespace".
          #
          # Also, ignore blank lines at the end of a block in a long if-else
          # chain, like this:
          #   if (condition1) {
          #     // Something followed by a blank line
          #
          #   } else if (condition2) {
          #     // Something else
          #   }
          if line_number + 1 < clean_lines.num_lines():
              next_line = raw[line_number + 1]
              if next_line and match(r'\s*}', next_line) and 'namespace' not in next_line and '} else ' not in next_line:
                  error(line_number, 'whitespace/blank_line', 3,
                        'Blank line at the end of a code block.  Is this needed?')
  
      # Next, we check for proper spacing with respect to comments.
      comment_position = line.find('//')
      if comment_position != -1:
          # Check if the // may be in quotes.  If so, ignore it
          # Comparisons made explicit for clarity
          if (line.count('"', 0, comment_position) - line.count('\\"', 0, comment_position)) % 2 == 0:   # not in quotes
              # Allow one space before end of line comment.
              if (not match(r'^\s*$', line[:comment_position])
                  and (comment_position >= 1
                       and ((line[comment_position - 1] not in string.whitespace)
                            or (comment_position >= 2
                                and line[comment_position - 2] in string.whitespace)))):
                  error(line_number, 'whitespace/comments', 5,
                        'One space before end of line comments')
              # There should always be a space between the // and the comment
              commentend = comment_position + 2
              if commentend < len(line) and not line[commentend] == ' ':
                  # but some lines are exceptions -- e.g. if they're big
                  # comment delimiters like:
                  # //----------------------------------------------------------
                  # or they begin with multiple slashes followed by a space:
                  # //////// Header comment
                  matched = (search(r'[=/-]{4,}\s*$', line[commentend:])
                             or search(r'^/+ ', line[commentend:]))
                  if not matched:
                      error(line_number, 'whitespace/comments', 4,
                            'Should have a space between // and comment')
  
      line = clean_lines.elided[line_number]  # get rid of comments and strings
  
      # Don't try to do spacing checks for operator methods
      line = sub(r'operator(==|!=|<|<<|<=|>=|>>|>|\+=|-=|\*=|/=|%=|&=|\|=|^=|<<=|>>=|/)\(', 'operator\(', line)
      # Don't try to do spacing checks for #include or #import statements at
      # minimum because it messes up checks for spacing around /
      if match(r'\s*#\s*(?:include|import)', line):
          return
      if search(r'[\w.]=[\w.]', line):
          error(line_number, 'whitespace/operators', 4,
                'Missing spaces around =')
  
      # FIXME: It's not ok to have spaces around binary operators like .
  
      # You should always have whitespace around binary operators.
      # Alas, we can't test < or > because they're legitimately used sans spaces
      # (a->b, vector<int> a).  The only time we can tell is a < with no >, and
      # only if it's not template params list spilling into the next line.
      matched = search(r'[^<>=!\s](==|!=|\+=|-=|\*=|/=|/|\|=|&=|<<=|>>=|<=|>=|\|\||\||<<)[^<>=!\s]', line)
      if not matched:
          # Note that while it seems that the '<[^<]*' term in the following
          # regexp could be simplified to '<.*', which would indeed match
          # the same class of strings, the [^<] means that searching for the
          # regexp takes linear rather than quadratic time.
          if not search(r'<[^<]*,\s*$', line):  # template params spill
              matched = search(r'[^<>=!\s](<)[^<>=!\s]([^>]|->)*$', line)
      if not matched:
          # Regardless of template arguments or operator>>, \w should not
          # follow >>.
          matched = search(r'(>>)\w', line)
          # If the line has no template arguments, >> is operator>>.
          # FIXME: This doesn't handle line-breaks inside template arguments.
          if not matched and not search(r'<', line):
              matched = search(r'\w(>>)', line)
  
      if matched:
          error(line_number, 'whitespace/operators', 3,
                'Missing spaces around %s' % matched.group(1))
  
      # There shouldn't be space around unary operators
      matched = search(r'(!\s|~\s|[\s]--[\s;]|[\s]\+\+[\s;])', line)
      if matched:
          error(line_number, 'whitespace/operators', 4,
                'Extra space for operator %s' % matched.group(1))
  
      # A pet peeve of mine: no spaces after an if, while, switch, or for
      matched = search(r' (if\(|for\(|foreach\(|while\(|switch\()', line)
      if matched:
          error(line_number, 'whitespace/parens', 5,
                'Missing space before ( in %s' % matched.group(1))
  
      # For if/for/foreach/while/switch, the left and right parens should be
      # consistent about how many spaces are inside the parens, and
      # there should either be zero or one spaces inside the parens.
      # We don't want: "if ( foo)" or "if ( foo   )".
      # Exception: "for ( ; foo; bar)" and "for (foo; bar; )" are allowed.
      matched = search(r'\b(?P<statement>if|for|foreach|while|switch)\s*\((?P<remainder>.*)$', line)
      if matched:
          statement = matched.group('statement')
          condition, rest = up_to_unmatched_closing_paren(matched.group('remainder'))
          if condition is not None:
              condition_match = search(r'(?P<leading>[ ]*)(?P<separator>.).*[^ ]+(?P<trailing>[ ]*)', condition)
              if condition_match:
                  n_leading = len(condition_match.group('leading'))
                  n_trailing = len(condition_match.group('trailing'))
                  if n_leading != 0:
                      for_exception = statement == 'for' and condition.startswith(' ;')
                      if not for_exception:
                          error(line_number, 'whitespace/parens', 5,
                                'Extra space after ( in %s' % statement)
                  if n_trailing != 0:
                      for_exception = statement == 'for' and condition.endswith('; ')
                      if not for_exception:
                          error(line_number, 'whitespace/parens', 5,
                                'Extra space before ) in %s' % statement)
  
              # Do not check for more than one command in macros
              in_preprocessor_directive = match(r'\s*#', line)
              if not in_preprocessor_directive and not match(r'((\s*{\s*}?)|(\s*;?))\s*\\?$', rest):
                  error(line_number, 'whitespace/parens', 4,
                        'More than one command on the same line in %s' % statement)
  
      # You should always have a space after a comma (either as fn arg or operator)
      if search(r',[^\s]', line):
          error(line_number, 'whitespace/comma', 3,
                'Missing space after ,')
  
      matched = search(r'^\s*(?P<token1>[a-zA-Z0-9_\*&]+)\s\s+(?P<token2>[a-zA-Z0-9_\*&]+)', line)
      if matched:
          error(line_number, 'whitespace/declaration', 3,
                'Extra space between %s and %s' % (matched.group('token1'), matched.group('token2')))
  
      if file_extension == 'cpp':
          # C++ should have the & or * beside the type not the variable name.
          matched = match(r'\s*\w+(?<!\breturn|\bdelete)\s+(?P<pointer_operator>\*|\&)\w+', line)
          if matched:
              error(line_number, 'whitespace/declaration', 3,
                    'Declaration has space between type name and %s in %s' % (matched.group('pointer_operator'), matched.group(0).strip()))
  
      elif file_extension == 'c':
          # C Pointer declaration should have the * beside the variable not the type name.
          matched = search(r'^\s*\w+\*\s+\w+', line)
          if matched:
              error(line_number, 'whitespace/declaration', 3,
                    'Declaration has space between * and variable name in %s' % matched.group(0).strip())
  
      # Next we will look for issues with function calls.
      check_spacing_for_function_call(line, line_number, error)
  
      # Except after an opening paren, you should have spaces before your braces.
      # And since you should never have braces at the beginning of a line, this is
      # an easy test.
      if search(r'[^ ({]{', line):
          error(line_number, 'whitespace/braces', 5,
                'Missing space before {')
  
      # Make sure '} else {' has spaces.
      if search(r'}else', line):
          error(line_number, 'whitespace/braces', 5,
                'Missing space before else')
  
      # You shouldn't have spaces before your brackets, except maybe after
      # 'delete []' or 'new char * []'.
      if search(r'\w\s+\[', line) and not search(r'delete\s+\[', line):
          error(line_number, 'whitespace/braces', 5,
                'Extra space before [')
  
      # There should always be zero or one space in between braces on the same line.
      if search(r'\{\s\s+\}', line):
          error(line_number, 'whitespace/braces', 5, 'Too many spaces inside { }.')
  
      # You shouldn't have a space before a semicolon at the end of the line.
      # There's a special case for "for" since the style guide allows space before
      # the semicolon there.
      if search(r':\s*;\s*$', line):
          error(line_number, 'whitespace/semicolon', 5,
                'Semicolon defining empty statement. Use { } instead.')
      elif search(r'^\s*;\s*$', line):
          error(line_number, 'whitespace/semicolon', 5,
                'Line contains only semicolon. If this should be an empty statement, '
                'use { } instead.')
      elif search(r'\s+;\s*$', line) and not search(r'\bfor\b', line):
          error(line_number, 'whitespace/semicolon', 5,
                'Extra space before last semicolon. If this should be an empty '
                'statement, use { } instead.')
      elif (search(r'\b(for|while)\s*\(.*\)\s*;\s*$', line)
            and line.count('(') == line.count(')')
            # Allow do {} while();
            and not search(r'}\s*while', line)):
          error(line_number, 'whitespace/semicolon', 5,
                'Semicolon defining empty statement for this loop. Use { } instead.')
  
  
  def get_previous_non_blank_line(clean_lines, line_number):
      """Return the most recent non-blank line and its line number.
  
      Args:
        clean_lines: A CleansedLines instance containing the file contents.
        line_number: The number of the line to check.
  
      Returns:
        A tuple with two elements.  The first element is the contents of the last
        non-blank line before the current line, or the empty string if this is the
        first non-blank line.  The second is the line number of that line, or -1
        if this is the first non-blank line.
      """
  
      previous_line_number = line_number - 1
      while previous_line_number >= 0:
          previous_line = clean_lines.elided[previous_line_number]
          if not is_blank_line(previous_line):     # if not a blank line...
              return (previous_line, previous_line_number)
          previous_line_number -= 1
      return ('', -1)
  
  
  def check_namespace_indentation(clean_lines, line_number, file_extension, file_state, error):
      """Looks for indentation errors inside of namespaces.
  
      Args:
        clean_lines: A CleansedLines instance containing the file.
        line_number: The number of the line to check.
        file_extension: The extension (dot not included) of the file.
        file_state: A _FileState instance which maintains information about
                    the state of things in the file.
        error: The function to call with any errors found.
      """
  
      line = clean_lines.elided[line_number]  # Get rid of comments and strings.
  
      namespace_match = match(r'(?P<namespace_indentation>\s*)namespace\s+\S+\s*{\s*$', line)
      if not namespace_match:
          return
  
      current_indentation_level = len(namespace_match.group('namespace_indentation'))
      if current_indentation_level > 0:
          # Don't warn about an indented namespace if we already warned about indented code.
          if not file_state.did_inside_namespace_indent_warning():
              error(line_number, 'whitespace/indent', 4,
                    'namespace should never be indented.')
          return
      looking_for_semicolon = False
      line_offset = 0
      in_preprocessor_directive = False
      for current_line in clean_lines.elided[line_number + 1:]:
          line_offset += 1
          if not current_line.strip():
              continue
          if not current_indentation_level:
              if not (in_preprocessor_directive or looking_for_semicolon):
                  if not match(r'\S', current_line) and not file_state.did_inside_namespace_indent_warning():
                      file_state.set_did_inside_namespace_indent_warning()
                      error(line_number + line_offset, 'whitespace/indent', 4,
                            'Code inside a namespace should not be indented.')
              if in_preprocessor_directive or (current_line.strip()[0] == '#'):  # This takes care of preprocessor directive syntax.
                  in_preprocessor_directive = current_line[-1] == '\\'
              else:
                  looking_for_semicolon = ((';' not in current_line) and (current_line.strip()
                                                                          [-1] != '}')) or (current_line[-1] == '\\')
          else:
              looking_for_semicolon = False  # If we have a brace we may not need a semicolon.
          current_indentation_level += current_line.count('{') - current_line.count('}')
          if current_indentation_level < 0:
              break
  
  
  def check_enum_casing(clean_lines, line_number, enum_state, error):
      """Looks for incorrectly named enum values.
  
      Args:
        clean_lines: A CleansedLines instance containing the file.
        line_number: The number of the line to check.
        enum_state: A _EnumState instance which maintains enum declaration state.
        error: The function to call with any errors found.
      """
  
      enum_state.is_webidl_enum |= bool(match(r'\s*// Web(?:Kit)?IDL enum\s*$', clean_lines.raw_lines[line_number]))
  
      line = clean_lines.elided[line_number]  # Get rid of comments and strings.
      if not enum_state.process_clean_line(line):
          error(line_number, 'readability/enum_casing', 4,
                'enum members should use InterCaps with an initial capital letter.')
  
  
  def check_directive_indentation(clean_lines, line_number, file_state, error):
      """Looks for indentation of preprocessor directives.
  
      Args:
        clean_lines: A CleansedLines instance containing the file.
        line_number: The number of the line to check.
        file_state: A _FileState instance which maintains information about
                    the state of things in the file.
        error: The function to call with any errors found.
      """
  
      line = clean_lines.elided[line_number]  # Get rid of comments and strings.
  
      indented_preprocessor_directives = match(r'\s+#', line)
      if not indented_preprocessor_directives:
          return
  
      error(line_number, 'whitespace/indent', 4, 'preprocessor directives (e.g., #ifdef, #define, #import) should never be indented.')
  
  
  def get_initial_spaces_for_line(clean_line):
      initial_spaces = 0
      while initial_spaces < len(clean_line) and clean_line[initial_spaces] == ' ':
          initial_spaces += 1
      return initial_spaces
  
  
  def check_indentation_amount(clean_lines, line_number, error):
      line = clean_lines.elided[line_number]
      initial_spaces = get_initial_spaces_for_line(line)
  
      if initial_spaces % 4:
          error(line_number, 'whitespace/indent', 3,
                'Weird number of spaces at line-start.  Are you using a 4-space indent?')
          return
  
      previous_line = get_previous_non_blank_line(clean_lines, line_number)[0]
      if not previous_line.strip() or match(r'\s*\w+\s*:\s*$', previous_line) or previous_line[0] == '#':
          return
  
      previous_line_initial_spaces = get_initial_spaces_for_line(previous_line)
      if initial_spaces > previous_line_initial_spaces + 4:
          error(line_number, 'whitespace/indent', 3, 'When wrapping a line, only indent 4 spaces.')
  
  
  def check_using_std(clean_lines, line_number, file_state, error):
      """Looks for 'using std::foo;' statements which should be replaced with 'using namespace std;'.
  
      Args:
        clean_lines: A CleansedLines instance containing the file.
        line_number: The number of the line to check.
        file_state: A _FileState instance which maintains information about
                    the state of things in the file.
        error: The function to call with any errors found.
      """
  
      # This check doesn't apply to C or Objective-C implementation files.
      if file_state.is_c_or_objective_c():
          return
  
      line = clean_lines.elided[line_number]  # Get rid of comments and strings.
  
      using_std_match = match(r'\s*using\s+std::(?P<method_name>\S+)\s*;\s*$', line)
      if not using_std_match:
          return
  
      method_name = using_std_match.group('method_name')
      # Exception for the established idiom for swapping objects in generic code.
      if method_name == 'swap':
          return
      error(line_number, 'build/using_std', 4,
            "Use 'using namespace std;' instead of 'using std::%s;'." % method_name)
  
  
  def check_max_min_macros(clean_lines, line_number, file_state, error):
      """Looks use of MAX() and MIN() macros that should be replaced with std::max() and std::min().
  
      Args:
        clean_lines: A CleansedLines instance containing the file.
        line_number: The number of the line to check.
        file_state: A _FileState instance which maintains information about
                    the state of things in the file.
        error: The function to call with any errors found.
      """
  
      # This check doesn't apply to C or Objective-C implementation files.
      if file_state.is_c_or_objective_c():
          return
  
      line = clean_lines.elided[line_number]  # Get rid of comments and strings.
  
      max_min_macros_search = search(r'\b(?P<max_min_macro>(MAX|MIN))\s*\(', line)
      if not max_min_macros_search:
          return
  
      max_min_macro = max_min_macros_search.group('max_min_macro')
      max_min_macro_lower = max_min_macro.lower()
      error(line_number, 'runtime/max_min_macros', 4,
            'Use std::%s() or std::%s<type>() instead of the %s() macro.'
            % (max_min_macro_lower, max_min_macro_lower, max_min_macro))
  
  
  def check_ctype_functions(clean_lines, line_number, file_state, error):
      """Looks for use of the standard functions in ctype.h and suggest they be replaced
         by use of equivalent ones in <wtf/ASCIICType.h>?.
  
      Args:
        clean_lines: A CleansedLines instance containing the file.
        line_number: The number of the line to check.
        file_state: A _FileState instance which maintains information about
                    the state of things in the file.
        error: The function to call with any errors found.
      """
  
      line = clean_lines.elided[line_number]  # Get rid of comments and strings.
  
      ctype_function_search = search(
          r'\b(?P<ctype_function>(isalnum|isalpha|isascii|isblank|iscntrl|isdigit|isgraph|islower|isprint|ispunct|isspace|isupper|isxdigit|toascii|tolower|toupper))\s*\(', line)
      if not ctype_function_search:
          return
  
      ctype_function = ctype_function_search.group('ctype_function')
      error(line_number, 'runtime/ctype_function', 4,
            'Use equivalent function in <wtf/ASCIICType.h> instead of the %s() function.'
            % (ctype_function))
  
  
  def check_switch_indentation(clean_lines, line_number, error):
      """Looks for indentation errors inside of switch statements.
  
      Args:
        clean_lines: A CleansedLines instance containing the file.
        line_number: The number of the line to check.
        error: The function to call with any errors found.
      """
  
      line = clean_lines.elided[line_number]  # Get rid of comments and strings.
  
      switch_match = match(r'(?P<switch_indentation>\s*)switch\s*\(.+\)\s*{\s*$', line)
      if not switch_match:
          return
  
      switch_indentation = switch_match.group('switch_indentation')
      inner_indentation = switch_indentation + ' ' * 4
      line_offset = 0
      encountered_nested_switch = False
  
      for current_line in clean_lines.elided[line_number + 1:]:
          line_offset += 1
  
          # Skip not only empty lines but also those with preprocessor directives.
          if current_line.strip() == '' or current_line.startswith('#'):
              continue
  
          if match(r'\s*switch\s*\(.+\)\s*{\s*$', current_line):
              # Complexity alarm - another switch statement nested inside the one
              # that we're currently testing. We'll need to track the extent of
              # that inner switch if the upcoming label tests are still supposed
              # to work correctly. Let's not do that; instead, we'll finish
              # checking this line, and then leave it like that. Assuming the
              # indentation is done consistently (even if incorrectly), this will
              # still catch all indentation issues in practice.
              encountered_nested_switch = True
  
          current_indentation_match = match(r'(?P<indentation>\s*)(?P<remaining_line>.*)$', current_line)
          current_indentation = current_indentation_match.group('indentation')
          remaining_line = current_indentation_match.group('remaining_line')
  
          # End the check at the end of the switch statement.
          if remaining_line.startswith('}') and current_indentation == switch_indentation:
              break
          # Case and default branches should not be indented. The regexp also
          # catches single-line cases like "default: break;" but does not trigger
          # on stuff like "Document::Foo();".
          elif match(r'(default|case\s+.*)\s*:([^:].*)?$', remaining_line):
              if current_indentation != switch_indentation:
                  error(line_number + line_offset, 'whitespace/indent', 4,
                        'A case label should not be indented, but line up with its switch statement.')
                  # Don't throw an error for multiple badly indented labels,
                  # one should be enough to figure out the problem.
                  break
          # We ignore goto labels at the very beginning of a line.
          elif match(r'\w+\s*:\s*$', remaining_line):
              continue
          # It's not a goto label, so check if it's indented at least as far as
          # the switch statement plus one more level of indentation.
          elif not current_indentation.startswith(inner_indentation):
              error(line_number + line_offset, 'whitespace/indent', 4,
                    'Non-label code inside switch statements should be indented.')
              # Don't throw an error for multiple badly indented statements,
              # one should be enough to figure out the problem.
              break
  
          if encountered_nested_switch:
              break
  
  
  def check_braces(clean_lines, line_number, error):
      """Looks for misplaced braces (e.g. at the end of line).
  
      Args:
        clean_lines: A CleansedLines instance containing the file.
        line_number: The number of the line to check.
        error: The function to call with any errors found.
      """
  
      line = clean_lines.elided[line_number]  # Get rid of comments and strings.
  
      if match(r'\s*{\s*$', line):
          # We allow an open brace to start a line in the case where someone
          # is using braces for function definition or in a block to
          # explicitly create a new scope, which is commonly used to control
          # the lifetime of stack-allocated variables.  We don't detect this
          # perfectly: we just don't complain if the last non-whitespace
          # character on the previous non-blank line is ';', ':', '{', '}',
          # ')' or is like a function declaration, and doesn't begin with
          # 'if|for|while|switch|else' without a beginning '{'.
          # We also allow '#' for #endif and '=' for array initialization.
          previous_line = get_previous_non_blank_line(clean_lines, line_number)[0]
          if ((not search(r'[;:}{)=]\s*$|\)\s*((const|override|final)\s*)*\s*(->\s*.+)?$', previous_line)
               or search(r'^\s*\b(if|for|foreach|while|switch|else)\b.*[^{]\s*$', previous_line))
                  and previous_line.find('#') < 0):
              error(line_number, 'whitespace/braces', 4,
                    'This { should be at the end of the previous line')
      elif (search(r'\)\s*(((const|override|final)\s*)*\s*)?{\s*$', line)
            and line.count('(') == line.count(')')
            and not search(r'\b(if|for|foreach|while|switch)\b', line)
            and not match(r'\s+[A-Z_][A-Z_0-9]+\b', line)):
          error(line_number, 'whitespace/braces', 4,
                'Place brace on its own line for function definitions.')
  
      # An else clause should be on the same line as the preceding closing brace.
      if match(r'\s*else\s*', line):
          previous_line = get_previous_non_blank_line(clean_lines, line_number)[0]
          if match(r'\s*}\s*$', previous_line):
              error(line_number, 'whitespace/newline', 4,
                    'An else should appear on the same line as the preceding }')
  
      # Likewise, an else should never have the else clause on the same line
      if search(r'\belse [^\s{]', line) and not search(r'\belse if\b', line):
          error(line_number, 'whitespace/newline', 4,
                'Else clause should never be on same line as else (use 2 lines)')
  
      # In the same way, a do/while should never be on one line
      if match(r'\s*do [^\s{]', line):
          error(line_number, 'whitespace/newline', 4,
                'do/while clauses should not be on a single line')
  
      # Braces shouldn't be followed by a ; unless they're defining a struct
      # or initializing an array.
      # We can't tell in general, but we can for some common cases.
      previous_line_number = line_number
      while True:
          (previous_line, previous_line_number) = get_previous_non_blank_line(clean_lines, previous_line_number)
          if match(r'\s+{.*}\s*;', line) and not previous_line.count(';'):
              line = previous_line + line
          else:
              break
      if (search(r'{.*}\s*;', line)
              and line.count('{') == line.count('}')
              and not search(r'struct|class|enum|\s*=\s*{', line)):
          error(line_number, 'readability/braces', 4,
                "You don't need a ; after a }")
  
  
  def check_exit_statement_simplifications(clean_lines, line_number, error):
      """Looks for else or else-if statements that should be written as an
      if statement when the prior if concludes with a return, break, continue or
      goto statement.
  
      Args:
        clean_lines: A CleansedLines instance containing the file.
        line_number: The number of the line to check.
        error: The function to call with any errors found.
      """
  
      line = clean_lines.elided[line_number]  # Get rid of comments and strings.
  
      else_match = match(r'(?P<else_indentation>\s*)(\}\s*)?else(\s+if\s*\(|(?P<else>\s*(\{\s*)?\Z))', line)
      if not else_match:
          return
  
      else_indentation = else_match.group('else_indentation')
      inner_indentation = else_indentation + ' ' * 4
  
      previous_lines = clean_lines.elided[:line_number]
      previous_lines.reverse()
      line_offset = 0
      encountered_exit_statement = False
  
      for current_line in previous_lines:
          line_offset -= 1
  
          # Skip not only empty lines but also those with preprocessor directives
          # and goto labels.
          if current_line.strip() == '' or current_line.startswith('#') or match(r'\w+\s*:\s*$', current_line):
              continue
  
          # Skip lines with closing braces on the original indentation level.
          # Even though the styleguide says they should be on the same line as
          # the "else if" statement, we also want to check for instances where
          # the current code does not comply with the coding style. Thus, ignore
          # these lines and proceed to the line before that.
          if current_line == else_indentation + '}':
              continue
  
          current_indentation_match = match(r'(?P<indentation>\s*)(?P<remaining_line>.*)$', current_line)
          current_indentation = current_indentation_match.group('indentation')
          remaining_line = current_indentation_match.group('remaining_line')
  
          # As we're going up the lines, the first real statement to encounter
          # has to be an exit statement (return, break, continue or goto) -
          # otherwise, this check doesn't apply.
          if not encountered_exit_statement:
              # We only want to find exit statements if they are on exactly
              # the same level of indentation as expected from the code inside
              # the block. If the indentation doesn't strictly match then we
              # might have a nested if or something, which must be ignored.
              if current_indentation != inner_indentation:
                  break
              if match(r'(return(\W+.*)|(break|continue)\s*;|goto\s*\w+;)$', remaining_line):
                  encountered_exit_statement = True
                  continue
              break
  
          # When code execution reaches this point, we've found an exit statement
          # as last statement of the previous block. Now we only need to make
          # sure that the block belongs to an "if", then we can throw an error.
  
          # Skip lines with opening braces on the original indentation level,
          # similar to the closing braces check above. ("if (condition)\n{")
          if current_line == else_indentation + '{':
              continue
  
          # Skip everything that's further indented than our "else" or "else if".
          if current_indentation.startswith(else_indentation) and current_indentation != else_indentation:
              continue
  
          # So we've got a line with same (or less) indentation. Is it an "if"?
          # If yes: throw an error. If no: don't throw an error.
          # Whatever the outcome, this is the end of our loop.
          if match(r'if\s*\(', remaining_line):
              if else_match.start('else') != -1:
                  error(line_number + line_offset, 'readability/control_flow', 4,
                        'An else statement can be removed when the prior "if" '
                        'concludes with a return, break, continue or goto statement.')
              else:
                  error(line_number + line_offset, 'readability/control_flow', 4,
                        'An else if statement should be written as an if statement '
                        'when the prior "if" concludes with a return, break, '
                        'continue or goto statement.')
          break
  
  
  def replaceable_check(operator, macro, line):
      """Determine whether a basic CHECK can be replaced with a more specific one.
  
      For example suggest using CHECK_EQ instead of CHECK(a == b) and
      similarly for CHECK_GE, CHECK_GT, CHECK_LE, CHECK_LT, CHECK_NE.
  
      Args:
        operator: The C++ operator used in the CHECK.
        macro: The CHECK or EXPECT macro being called.
        line: The current source line.
  
      Returns:
        True if the CHECK can be replaced with a more specific one.
      """
  
      # This matches decimal and hex integers, strings, and chars (in that order).
      match_constant = r'([-+]?(\d+|0[xX][0-9a-fA-F]+)[lLuU]{0,3}|".*"|\'.*\')'
  
      # Expression to match two sides of the operator with something that
      # looks like a literal, since CHECK(x == iterator) won't compile.
      # This means we can't catch all the cases where a more specific
      # CHECK is possible, but it's less annoying than dealing with
      # extraneous warnings.
      match_this = (r'\s*' + macro + r'\((\s*' +
                    match_constant + r'\s*' + operator + r'[^<>].*|'
                    r'.*[^<>]' + operator + r'\s*' + match_constant +
                    r'\s*\))')
  
      # Don't complain about CHECK(x == NULL) or similar because
      # CHECK_EQ(x, NULL) won't compile (requires a cast).
      # Also, don't complain about more complex boolean expressions
      # involving && or || such as CHECK(a == b || c == d).
      return match(match_this, line) and not search(r'NULL|&&|\|\|', line)
  
  
  def check_check(clean_lines, line_number, error):
      """Checks the use of CHECK and EXPECT macros.
  
      Args:
        clean_lines: A CleansedLines instance containing the file.
        line_number: The number of the line to check.
        error: The function to call with any errors found.
      """
  
      # Decide the set of replacement macros that should be suggested
      raw_lines = clean_lines.raw_lines
      current_macro = ''
      for macro in _CHECK_MACROS:
          if raw_lines[line_number].find(macro) >= 0:
              current_macro = macro
              break
      if not current_macro:
          # Don't waste time here if line doesn't contain 'CHECK' or 'EXPECT'
          return
  
      line = clean_lines.elided[line_number]        # get rid of comments and strings
  
      # Encourage replacing plain CHECKs with CHECK_EQ/CHECK_NE/etc.
      for operator in ['==', '!=', '>=', '>', '<=', '<']:
          if replaceable_check(operator, current_macro, line):
              error(line_number, 'readability/check', 2,
                    'Consider using %s instead of %s(a %s b)' % (
                        _CHECK_REPLACEMENT[current_macro][operator],
                        current_macro, operator))
              break
  
  
  def check_deprecated_macros(clean_lines, line_number, error):
      """Checks the use of obsolete macros.
  
      Args:
        clean_lines: A CleansedLines instance containing the file.
        line_number: The number of the line to check.
        error: The function to call with any errors found.
      """
  
      line = clean_lines.elided[line_number]
      for pair in _DEPRECATED_MACROS:
          if search(r'\b' + pair[0] + r'\(', line):
              error(line_number, 'build/deprecated', 5,
                    '%s is deprecated. Use %s instead.' % (pair[0], pair[1]))
  
  
  def check_for_comparisons_to_boolean(clean_lines, line_number, error):
      # Get the line without comments and strings.
      line = clean_lines.elided[line_number]
  
      # Must include NULL here, as otherwise users will convert NULL to 0 and
      # then we can't catch it, since it looks like a valid integer comparison.
      if search(r'[=!]=\s*(NULL|nullptr|true|false)[^\w.]', line) or search(r'[^\w.](NULL|nullptr|true|false)\s*[=!]=', line):
          if not search('LIKELY', line) and not search('UNLIKELY', line):
              error(line_number, 'readability/comparison_to_boolean', 5,
                    'Tests for true/false and null/non-null should be done without equality comparisons.')
  
  
  def check_for_null(clean_lines, line_number, file_state, error):
      # This check doesn't apply to C or Objective-C implementation files.
      if file_state.is_c_or_objective_c():
          return
  
      line = clean_lines.elided[line_number]
  
      # Don't warn about NULL usage in g_*(). See Bug 32858 and 39372.
      if search(r'\bg(_[a-z]+)+\b', line):
          return
  
      # Don't warn about NULL usage in gst_*(). See Bug 70498.
      if search(r'\bgst(_[a-z]+)+\b', line):
          return
  
      # Don't warn about NULL usage in gdk_pixbuf_save_to_*{join,concat}(). See Bug 43090.
      if search(r'\bgdk_pixbuf_save_to\w+\b', line):
          return
  
      # Don't warn about NULL usage in gtk_widget_style_get(),
      # gtk_style_context_get_style(), or gtk_style_context_get(). See Bug 51758
      if search(r'\bgtk_widget_style_get\(\w+\b', line) or search(r'\bgtk_style_context_get_style\(\w+\b',
                                                                  line) or search(r'\bgtk_style_context_get\(\w+\b', line):
          return
  
      # Don't warn about NULL usage in soup_server_new(). See Bug 77890.
      if search(r'\bsoup_server_new\(\w+\b', line):
          return
  
      if search(r'\bNULL\b', line):
          error(line_number, 'readability/null', 5, 'Use 0 instead of NULL.')
          return
  
      line = clean_lines.raw_lines[line_number]
      # See if NULL occurs in any comments in the line. If the search for NULL using the raw line
      # matches, then do the check with strings collapsed to avoid giving errors for
      # NULLs occurring in strings.
      if search(r'\bNULL\b', line) and search(r'\bNULL\b', CleansedLines.collapse_strings(line)):
          error(line_number, 'readability/null', 4, 'Use 0 or null instead of NULL (even in *comments*).')
  
  
  def get_line_width(line):
      """Determines the width of the line in column positions.
  
      Args:
        line: A string, which may be a Unicode string.
  
      Returns:
        The width of the line in column positions, accounting for Unicode
        combining characters and wide characters.
      """
      if isinstance(line, unicode):
          width = 0
          for c in unicodedata.normalize('NFC', line):
              if unicodedata.east_asian_width(c) in ('W', 'F'):
                  width += 2
              elif not unicodedata.combining(c):
                  width += 1
          return width
      return len(line)
  
  
  def check_conditional_and_loop_bodies_for_brace_violations(clean_lines, line_number, error):
      """Scans the bodies of conditionals and loops, and in particular
      all the arms of conditionals, for violations in the use of braces.
  
      Specifically:
  
      (1) If an arm omits braces, then the following statement must be on one
      physical line.
      (2) If any arm uses braces, all arms must use them.
  
      These checks are only done here if we find the start of an
      'if/for/foreach/while' statement, because this function fails fast
      if it encounters constructs it doesn't understand. Checks
      elsewhere validate other constraints, such as requiring '}' and
      'else' to be on the same line.
  
      Args:
        clean_lines: A CleansedLines instance containing the file.
        line_number: The number of the line to check.
        error: The function to call with any errors found.
      """
  
      # We work with the elided lines. Comments have been removed, but line
      # numbers are preserved, so we can still find situations where
      # single-expression control clauses span multiple lines, or when a
      # comment preceded the expression.
      lines = clean_lines.elided
      line = lines[line_number]
  
      # Match control structures.
      control_match = match(r'\s*(if|foreach|for|while)\s*\(', line)
      if not control_match:
          return
  
      # Found the start of a conditional or loop.
  
      # The following loop handles all potential arms of the control clause.
      # The initial conditions are the following:
      #   - We start on the opening paren '(' of the condition, *unless* we are
      #     handling an 'else' block, in which case there is no condition.
      #   - In the latter case, we start at the position just beyond the 'else'
      #     token.
      expect_conditional_expression = True
      know_whether_using_braces = False
      using_braces = False
      search_for_else_clause = control_match.group(1) == "if"
      current_pos = Position(line_number, control_match.end() - 1)
  
      while True:
          if expect_conditional_expression:
              # Try to find the end of the conditional expression,
              # potentially spanning multiple lines.
              open_paren_pos = current_pos
              close_paren_pos = close_expression(lines, open_paren_pos)
              if close_paren_pos.column < 0:
                  return
              current_pos = close_paren_pos
  
          end_line_of_conditional = current_pos.row
  
          # Find the start of the body.
          current_pos = _find_in_lines(r'\S', lines, current_pos, None)
          if not current_pos:
              return
  
          current_arm_uses_brace = False
          if lines[current_pos.row][current_pos.column] == '{':
              current_arm_uses_brace = True
          if know_whether_using_braces:
              if using_braces != current_arm_uses_brace:
                  error(current_pos.row, 'whitespace/braces', 4,
                        'If one part of an if-else statement uses curly braces, the other part must too.')
                  return
          know_whether_using_braces = True
          using_braces = current_arm_uses_brace
  
          if using_braces:
              # Skip over the entire arm.
              current_pos = close_expression(lines, current_pos)
              if current_pos.column < 0:
                  return
          else:
              # Skip over the current expression.
              current_line_number = current_pos.row
              current_pos = _find_in_lines(r';', lines, current_pos, None)
              if not current_pos:
                  return
              # If the end of the expression is beyond the line just after
              # the close parenthesis or control clause, we've found a
              # single-expression arm that spans multiple lines. (We don't
              # fire this error for expressions ending on the same line; that
              # is a different error, handled elsewhere.)
              if current_pos.row > 1 + end_line_of_conditional:
                  error(current_pos.row, 'whitespace/braces', 4,
                        'A conditional or loop body must use braces if the statement is more than one line long.')
                  return
              current_pos = Position(current_pos.row, 1 + current_pos.column)
  
          # At this point current_pos points just past the end of the last
          # arm. If we just handled the last control clause, we're done.
          if not search_for_else_clause:
              return
  
          # Scan forward for the next non-whitespace character, and see
          # whether we are continuing a conditional (with an 'else' or
          # 'else if'), or are done.
          current_pos = _find_in_lines(r'\S', lines, current_pos, None)
          if not current_pos:
              return
          next_nonspace_string = lines[current_pos.row][current_pos.column:]
          next_conditional = match(r'(else\s*if|else)', next_nonspace_string)
          if not next_conditional:
              # Done processing this 'if' and all arms.
              return
          if next_conditional.group(1) == "else if":
              current_pos = _find_in_lines(r'\(', lines, current_pos, None)
          else:
              current_pos.column += 4  # skip 'else'
              expect_conditional_expression = False
              search_for_else_clause = False
      # End while loop
  
  
  def check_redundant_virtual(clean_lines, linenum, error):
      """Checks if line contains a redundant "virtual" function-specifier.
  
      Args:
        clean_lines: A CleansedLines instance containing the file.
        linenum: The number of the line to check.
        error: The function to call with any errors found.
      """
  
      # Look for "virtual" on current line.
      line = clean_lines.elided[linenum]
      virtual = match(r'^(.*)(\bvirtual\b)(.*)$', line)
      if not virtual:
          return
  
      # Ignore "virtual" keywords that are near access-specifiers.  These
      # are only used in class base-specifier and do not apply to member
      # functions.
      if (search(r'\b(public|protected|private)\s+$', virtual.group(1)) or
              match(r'^\s+(public|protected|private)\b', virtual.group(3))):
          return
  
      # Ignore the "virtual" keyword from virtual base classes.  Usually
      # there is a column on the same line in these cases (virtual base
      # classes are rare in google3 because multiple inheritance is rare).
      if match(r'^.*[^:]:[^:].*$', line):
          return
  
      # Look for the next opening parenthesis.  This is the start of the
      # parameter list (possibly on the next line shortly after virtual).
      # TODO(unknown): doesn't work if there are virtual functions with
      # decltype() or other things that use parentheses, but csearch suggests
      # that this is rare.
      end_position = Position(-1, -1)
      start_col = len(virtual.group(2))
      for start_line in xrange(linenum, min(linenum + 3, clean_lines.num_lines())):
          line = clean_lines.elided[start_line][start_col:]
          parameter_list = match(r'^([^(]*)\(', line)
          if parameter_list:
              # Match parentheses to find the end of the parameter list
              end_position = close_expression(
                  clean_lines.elided, Position(start_line, start_col + len(parameter_list.group(1))))
              break
          start_col = 0
  
      if end_position.column < 0:
          return  # Couldn't find end of parameter list, give up
  
      # Look for "override" or "final" after the parameter list
      # (possibly on the next few lines).
      for i in xrange(end_position.row, min(end_position.row + 3, clean_lines.num_lines())):
          line = clean_lines.elided[i][end_position.column:]
          override_or_final = search(r'\b(override|final)\b', line)
          if override_or_final:
              error(linenum, 'readability/inheritance', 4,
                    ('"virtual" is redundant since function is '
                     'already declared as "%s"' % override_or_final.group(1)))
  
          # Set end_col to check whole lines after we are done with the
          # first line.
          end_col = 0
          if search(r'[^\w]\s*$', line):
              break
  
  
  def check_redundant_override(clean_lines, linenum, error):
      """Checks if line contains a redundant "override" virt-specifier.
  
      Args:
        clean_lines: A CleansedLines instance containing the file.
        linenum: The number of the line to check.
        error: The function to call with any errors found.
      """
      # Look for closing parenthesis nearby.  We need one to confirm where
      # the declarator ends and where the virt-specifier starts to avoid
      # false positives.
      line = clean_lines.elided[linenum]
      declarator_end = line.rfind(')')
      if declarator_end >= 0:
          fragment = line[declarator_end:]
      else:
          if linenum > 1 and clean_lines.elided[linenum - 1].rfind(')') >= 0:
              fragment = line
          else:
              return
  
          # Check that at most one of "override" or "final" is present, not both
      if search(r'\boverride\b', fragment) and search(r'\bfinal\b', fragment):
          error(linenum, 'readability/inheritance', 4,
                ('"override" is redundant since function is '
                 'already declared as "final"'))
  
  
  def check_style(clean_lines, line_number, file_extension, class_state, file_state, enum_state, error):
      """Checks rules from the 'C++ style rules' section of cppguide.html.
  
      Most of these rules are hard to test (naming, comment style), but we
      do what we can.  In particular we check for 4-space indents, line lengths,
      tab usage, spaces inside code, etc.
  
      Args:
        clean_lines: A CleansedLines instance containing the file.
        line_number: The number of the line to check.
        file_extension: The extension (without the dot) of the filename.
        class_state: A _ClassState instance which maintains information about
                     the current stack of nested class declarations being parsed.
        file_state: A _FileState instance which maintains information about
                    the state of things in the file.
        enum_state: A _EnumState instance which maintains the current enum state.
        error: The function to call with any errors found.
      """
  
      raw_lines = clean_lines.raw_lines
      line = raw_lines[line_number]
  
      if '\t' in line:
          error(line_number, 'whitespace/tab', 1,
                'Tab found; better to use spaces')
  
      cleansed_line = clean_lines.elided[line_number]
      if line and line[-1].isspace():
          error(line_number, 'whitespace/end_of_line', 4,
                'Line ends in whitespace.  Consider deleting these extra spaces.')
  
      if (cleansed_line.count(';') > 1
          # for loops are allowed two ;'s (and may run over two lines).
          and 'for' not in cleansed_line
          and (get_previous_non_blank_line(clean_lines, line_number)[0].find('for') == -1
               or get_previous_non_blank_line(clean_lines, line_number)[0].find(';') != -1)
          # It's ok to have many commands in a switch case that fits in 1 line
          and not (('case ' in cleansed_line
                    or 'default:' in cleansed_line)
                   and 'break;' in cleansed_line)
          # Also it's ok to have many commands in trivial single-line accessors in class definitions.
          and not (match(r'.*\(.*\).*{.*.}', line)
                   and class_state.classinfo_stack
                   and line.count('{') == line.count('}'))
          and not cleansed_line.startswith('#define ')
          # It's ok to use use WTF_MAKE_NONCOPYABLE and WTF_MAKE_FAST_ALLOCATED macros in 1 line
          and not (cleansed_line.find("WTF_MAKE_NONCOPYABLE") != -1
                   and cleansed_line.find("WTF_MAKE_FAST_ALLOCATED") != -1)):
          error(line_number, 'whitespace/newline', 4,
                'More than one command on the same line')
  
      if cleansed_line.strip().endswith('||') or cleansed_line.strip().endswith('&&'):
          error(line_number, 'whitespace/operators', 4,
                'Boolean expressions that span multiple lines should have their '
                'operators on the left side of the line instead of the right side.')
  
      # Some more style checks
      check_namespace_indentation(clean_lines, line_number, file_extension, file_state, error)
      check_directive_indentation(clean_lines, line_number, file_state, error)
      check_using_std(clean_lines, line_number, file_state, error)
      check_max_min_macros(clean_lines, line_number, file_state, error)
      check_ctype_functions(clean_lines, line_number, file_state, error)
      check_switch_indentation(clean_lines, line_number, error)
      check_braces(clean_lines, line_number, error)
      check_exit_statement_simplifications(clean_lines, line_number, error)
      check_spacing(file_extension, clean_lines, line_number, error)
      check_check(clean_lines, line_number, error)
      check_deprecated_macros(clean_lines, line_number, error)
      check_for_comparisons_to_boolean(clean_lines, line_number, error)
      check_for_null(clean_lines, line_number, file_state, error)
      check_indentation_amount(clean_lines, line_number, error)
      check_enum_casing(clean_lines, line_number, enum_state, error)
  
  
  _RE_PATTERN_INCLUDE_NEW_STYLE = re.compile(r'#include +"[^/]+\.h"')
  _RE_PATTERN_INCLUDE = re.compile(r'^\s*#\s*include\s*([<"])([^>"]*)[>"].*$')
  # Matches the first component of a filename delimited by -s and _s. That is:
  #  _RE_FIRST_COMPONENT.match('foo').group(0) == 'foo'
  #  _RE_FIRST_COMPONENT.match('foo.cpp').group(0) == 'foo'
  #  _RE_FIRST_COMPONENT.match('foo-bar_baz.cpp').group(0) == 'foo'
  #  _RE_FIRST_COMPONENT.match('foo_bar-baz.cpp').group(0) == 'foo'
  _RE_FIRST_COMPONENT = re.compile(r'^[^-_.]+')
  
  
  def _drop_common_suffixes(filename):
      """Drops common suffixes like _test.cpp or -inl.h from filename.
  
      For example:
        >>> _drop_common_suffixes('foo/foo-inl.h')
        'foo/foo'
        >>> _drop_common_suffixes('foo/bar/foo.cpp')
        'foo/bar/foo'
        >>> _drop_common_suffixes('foo/foo_internal.h')
        'foo/foo'
        >>> _drop_common_suffixes('foo/foo_unusualinternal.h')
        'foo/foo_unusualinternal'
  
      Args:
        filename: The input filename.
  
      Returns:
        The filename with the common suffix removed.
      """
      for suffix in ('test.cpp', 'regtest.cpp', 'unittest.cpp',
                     'inl.h', 'impl.h', 'internal.h'):
          if (filename.endswith(suffix) and len(filename) > len(suffix)
                  and filename[-len(suffix) - 1] in ('-', '_')):
              return filename[:-len(suffix) - 1]
      return os.path.splitext(filename)[0]
  
  
  def _classify_include(filename, include, is_system, include_state):
      """Figures out what kind of header 'include' is.
  
      Args:
        filename: The current file cpp_style is running over.
        include: The path to a #included file.
        is_system: True if the #include used <> rather than "".
        include_state: An _IncludeState instance in which the headers are inserted.
  
      Returns:
        One of the _XXX_HEADER constants.
  
      For example:
        >>> _classify_include('foo.cpp', 'foo.h', False)
        _PRIMARY_HEADER
        >>> _classify_include('foo.cpp', 'bar.h', False)
        _OTHER_HEADER
      """
  
      # If it is a system header we know it is classified as _OTHER_HEADER.
      if is_system and not include.startswith('public/'):
          return _OTHER_HEADER
  
      # There cannot be primary includes in header files themselves. Only an
      # include exactly matches the header filename will be is flagged as
      # primary, so that it triggers the "don't include yourself" check.
      if filename.endswith('.h') and filename != include:
          return _OTHER_HEADER
  
      # Qt's moc files do not follow the naming and ordering rules, so they should be skipped
      if include.startswith('moc_') and include.endswith('.cpp'):
          return _MOC_HEADER
  
      if include.endswith('.moc'):
          return _MOC_HEADER
  
      # If the target file basename starts with the include we're checking
      # then we consider it the primary header.
      target_base = FileInfo(filename).base_name()
      include_base = FileInfo(include).base_name()
  
      # If we haven't encountered a primary header, then be lenient in checking.
      if not include_state.visited_primary_section():
          if target_base.find(include_base) != -1:
              return _PRIMARY_HEADER
          # Qt private APIs use _p.h suffix.
          if include_base.find(target_base) != -1 and include_base.endswith('_p'):
              return _PRIMARY_HEADER
  
      # If we already encountered a primary header, perform a strict comparison.
      # In case the two filename bases are the same then the above lenient check
      # probably was a false positive.
      elif include_state.visited_primary_section() and target_base == include_base:
          if include == "ResourceHandleWin.h":
              # FIXME: Thus far, we've only seen one example of these, but if we
              # start to see more, please consider generalizing this check
              # somehow.
              return _OTHER_HEADER
          return _PRIMARY_HEADER
  
      return _OTHER_HEADER
  
  
  def _does_primary_header_exist(filename):
      """Return a primary header file name for a file, or empty string
      if the file is not source file or primary header does not exist.
      """
      fileinfo = FileInfo(filename)
      if not fileinfo.is_source():
          return False
      primary_header = fileinfo.no_extension() + ".h"
      return os.path.isfile(primary_header)
  
  
  def check_include_line(filename, file_extension, clean_lines, line_number, include_state, error):
      """Check rules that are applicable to #include lines.
  
      Strings on #include lines are NOT removed from elided line, to make
      certain tasks easier. However, to prevent false positives, checks
      applicable to #include lines in CheckLanguage must be put here.
  
      Args:
        filename: The name of the current file.
        file_extension: The current file extension, without the leading dot.
        clean_lines: A CleansedLines instance containing the file.
        line_number: The number of the line to check.
        include_state: An _IncludeState instance in which the headers are inserted.
        error: The function to call with any errors found.
      """
      # FIXME: For readability or as a possible optimization, consider
      #        exiting early here by checking whether the "build/include"
      #        category should be checked for the given filename.  This
      #        may involve having the error handler classes expose a
      #        should_check() method, in addition to the usual __call__
      #        method.
      line = clean_lines.lines[line_number]
  
      matched = _RE_PATTERN_INCLUDE.search(line)
      if not matched:
          return
  
      include = matched.group(2)
      is_system = (matched.group(1) == '<')
  
      # Look for any of the stream classes that are part of standard C++.
      if match(r'(f|ind|io|i|o|parse|pf|stdio|str|)?stream$', include):
          error(line_number, 'readability/streams', 3,
                'Streams are highly discouraged.')
  
      # Look for specific includes to fix.
      if include.startswith('wtf/') and is_system:
          error(line_number, 'build/include', 4,
                'wtf includes should be "wtf/file.h" instead of <wtf/file.h>.')
  
      if filename.find('/chromium/') != -1 and include.startswith('cc/CC'):
          error(line_number, 'build/include', 4,
                'cc includes should be "CCFoo.h" instead of "cc/CCFoo.h".')
  
      duplicate_header = include in include_state
      if duplicate_header:
          error(line_number, 'build/include', 4,
                '"%s" already included at %s:%s' %
                (include, filename, include_state[include]))
      else:
          include_state[include] = line_number
  
      header_type = _classify_include(filename, include, is_system, include_state)
      primary_header_exists = _does_primary_header_exist(filename)
      include_state.header_types[line_number] = header_type
  
      # Only proceed if this isn't a duplicate header.
      if duplicate_header:
          return
  
      # We want to ensure that headers appear in the right order:
      # 1) for implementation files: primary header, blank line, alphabetically sorted
      # 2) for header files: alphabetically sorted
      # The include_state object keeps track of the last type seen
      # and complains if the header types are out of order or missing.
      error_message = include_state.check_next_include_order(header_type,
                                                             file_extension == "h",
                                                             primary_header_exists)
  
      # Check to make sure we have a blank line after primary header.
      if not error_message and header_type == _PRIMARY_HEADER:
          next_line = clean_lines.raw_lines[line_number + 1]
          if not is_blank_line(next_line):
              error(line_number, 'build/include_order', 4,
                    'You should add a blank line after implementation file\'s own header.')
  
      # Check to make sure all headers besides the primary header are
      # alphabetically sorted. Skip Qt's moc files.
      if not error_message and header_type == _OTHER_HEADER:
          previous_line_number = line_number - 1
          previous_line = clean_lines.lines[previous_line_number]
          previous_match = _RE_PATTERN_INCLUDE.search(previous_line)
          while (not previous_match and previous_line_number > 0
                 and not search(r'\A(#if|#ifdef|#ifndef|#else|#elif|#endif)', previous_line)):
              previous_line_number -= 1
              previous_line = clean_lines.lines[previous_line_number]
              previous_match = _RE_PATTERN_INCLUDE.search(previous_line)
          if previous_match:
              previous_header_type = include_state.header_types[previous_line_number]
              if previous_header_type == _OTHER_HEADER and previous_line.strip() > line.strip():
                  # This type of error is potentially a problem with this line or the previous one,
                  # so if the error is filtered for one line, report it for the next. This is so that
                  # we properly handle patches, for which only modified lines produce errors.
                  if not error(line_number - 1, 'build/include_order', 4, 'Alphabetical sorting problem.'):
                      error(line_number, 'build/include_order', 4, 'Alphabetical sorting problem.')
  
      if error_message:
          if file_extension == 'h':
              error(line_number, 'build/include_order', 4,
                    '%s Should be: alphabetically sorted.' %
                    error_message)
          else:
              error(line_number, 'build/include_order', 4,
                    '%s Should be: primary header, blank line, and then alphabetically sorted.' %
                    error_message)
  
  
  def check_language(filename, clean_lines, line_number, file_extension, include_state,
                     file_state, error):
      """Checks rules from the 'C++ language rules' section of cppguide.html.
  
      Some of these rules are hard to test (function overloading, using
      uint32 inappropriately), but we do the best we can.
  
      Args:
        filename: The name of the current file.
        clean_lines: A CleansedLines instance containing the file.
        line_number: The number of the line to check.
        file_extension: The extension (without the dot) of the filename.
        include_state: An _IncludeState instance in which the headers are inserted.
        file_state: A _FileState instance which maintains information about
                    the state of things in the file.
        error: The function to call with any errors found.
      """
      # If the line is empty or consists of entirely a comment, no need to
      # check it.
      line = clean_lines.elided[line_number]
      if not line:
          return
  
      matched = _RE_PATTERN_INCLUDE.search(line)
      if matched:
          check_include_line(filename, file_extension, clean_lines, line_number, include_state, error)
          return
  
      # FIXME: figure out if they're using default arguments in fn proto.
  
      # Check to see if they're using an conversion function cast.
      # I just try to capture the most common basic types, though there are more.
      # Parameterless conversion functions, such as bool(), are allowed as they are
      # probably a member operator declaration or default constructor.
      matched = search(
          r'\b(int|float|double|bool|char|int32|uint32|int64|uint64)\([^)]', line)
      if matched:
          # gMock methods are defined using some variant of MOCK_METHODx(name, type)
          # where type may be float(), int(string), etc.  Without context they are
          # virtually indistinguishable from int(x) casts.
          if not match(r'^\s*MOCK_(CONST_)?METHOD\d+(_T)?\(', line):
              error(line_number, 'readability/casting', 4,
                    'Using deprecated casting style.  '
                    'Use static_cast<%s>(...) instead' %
                    matched.group(1))
  
      check_c_style_cast(line_number, line, clean_lines.raw_lines[line_number],
                         'static_cast',
                         r'\((int|float|double|bool|char|u?int(16|32|64))\)',
                         error)
      # This doesn't catch all cases.  Consider (const char * const)"hello".
      check_c_style_cast(line_number, line, clean_lines.raw_lines[line_number],
                         'reinterpret_cast', r'\((\w+\s?\*+\s?)\)', error)
  
      # In addition, we look for people taking the address of a cast.  This
      # is dangerous -- casts can assign to temporaries, so the pointer doesn't
      # point where you think.
      if search(
              r'(&\([^)]+\)[\w(])|(&(static|dynamic|reinterpret)_cast\b)', line):
          error(line_number, 'runtime/casting', 4,
                ('Are you taking an address of a cast?  '
                 'This is dangerous: could be a temp var.  '
                 'Take the address before doing the cast, rather than after'))
  
      # Check for people declaring static/global STL strings at the top level.
      # This is dangerous because the C++ language does not guarantee that
      # globals with constructors are initialized before the first access.
      matched = match(
          r'((?:|static +)(?:|const +))string +([a-zA-Z0-9_:]+)\b(.*)',
          line)
      # Make sure it's not a function.
      # Function template specialization looks like: "string foo<Type>(...".
      # Class template definitions look like: "string Foo<Type>::Method(...".
      if matched and not match(r'\s*(<.*>)?(::[a-zA-Z0-9_]+)?\s*\(([^"]|$)',
                               matched.group(3)):
          error(line_number, 'runtime/string', 4,
                'For a static/global string constant, use a C style string instead: '
                '"%schar %s[]".' %
                (matched.group(1), matched.group(2)))
  
      # Check that we're not using RTTI outside of testing code.
      if search(r'\bdynamic_cast<', line):
          error(line_number, 'runtime/rtti', 5,
                'Do not use dynamic_cast<>.  If you need to cast within a class '
                "hierarchy, use static_cast<> to upcast.  Google doesn't support "
                'RTTI.')
  
      if search(r'\b([A-Za-z0-9_]*_)\(\1\)', line):
          error(line_number, 'runtime/init', 4,
                'You seem to be initializing a member variable with itself.')
  
      if file_extension == 'h':
          # FIXME: check that 1-arg constructors are explicit.
          #        How to tell it's a constructor?
          #        (handled in check_for_non_standard_constructs for now)
          pass
  
      # Check if people are using the verboten C basic types.  The only exception
      # we regularly allow is "unsigned short port" for port.
      if search(r'\bshort port\b', line):
          if not search(r'\bunsigned short port\b', line):
              error(line_number, 'runtime/int', 4,
                    'Use "unsigned short" for ports, not "short"')
  
      # When snprintf is used, the second argument shouldn't be a literal.
      matched = search(r'snprintf\s*\(([^,]*),\s*([0-9]*)\s*,', line)
      if matched:
          error(line_number, 'runtime/printf', 3,
                'If you can, use sizeof(%s) instead of %s as the 2nd arg '
                'to snprintf.' % (matched.group(1), matched.group(2)))
  
      # Check if some verboten C functions are being used.
      if search(r'\bsprintf\b', line):
          error(line_number, 'runtime/printf', 5,
                'Never use sprintf.  Use snprintf instead.')
      matched = search(r'\b(strcpy|strcat)\b', line)
      if matched:
          error(line_number, 'runtime/printf', 4,
                'Almost always, snprintf is better than %s' % matched.group(1))
  
      if search(r'\bsscanf\b', line):
          error(line_number, 'runtime/printf', 1,
                'sscanf can be ok, but is slow and can overflow buffers.')
  
      # Check for suspicious usage of "if" like
      # } if (a == b) {
      if search(r'\}\s*if\s*\(', line):
          error(line_number, 'readability/braces', 4,
                'Did you mean "else if"? If not, start a new line for "if".')
  
      # Check for potential format string bugs like printf(foo).
      # We constrain the pattern not to pick things like DocidForPrintf(foo).
      # Not perfect but it can catch printf(foo.c_str()) and printf(foo->c_str())
      matched = re.search(r'\b((?:string)?printf)\s*\(([\w.\->()]+)\)', line, re.I)
      if matched:
          error(line_number, 'runtime/printf', 4,
                'Potential format string bug. Do %s("%%s", %s) instead.'
                % (matched.group(1), matched.group(2)))
  
      # Check for potential memset bugs like memset(buf, sizeof(buf), 0).
      matched = search(r'memset\s*\(([^,]*),\s*([^,]*),\s*0\s*\)', line)
      if matched and not match(r"^''|-?[0-9]+|0x[0-9A-Fa-f]$", matched.group(2)):
          error(line_number, 'runtime/memset', 4,
                'Did you mean "memset(%s, 0, %s)"?'
                % (matched.group(1), matched.group(2)))
  
      # Detect variable-length arrays.
      matched = match(r'\s*(.+::)?(\w+) [a-z]\w*\[(.+)];', line)
      if (matched and matched.group(2) != 'return' and matched.group(2) != 'delete' and
              matched.group(3).find(']') == -1):
          # Split the size using space and arithmetic operators as delimiters.
          # If any of the resulting tokens are not compile time constants then
          # report the error.
          tokens = re.split(r'\s|\+|\-|\*|\/|<<|>>]', matched.group(3))
          is_const = True
          skip_next = False
          for tok in tokens:
              if skip_next:
                  skip_next = False
                  continue
  
              if search(r'sizeof\(.+\)', tok):
                  continue
              if search(r'arraysize\(\w+\)', tok):
                  continue
  
              tok = tok.lstrip('(')
              tok = tok.rstrip(')')
              if not tok:
                  continue
              if match(r'\d+', tok):
                  continue
              if match(r'0[xX][0-9a-fA-F]+', tok):
                  continue
              if match(r'k[A-Z0-9]\w*', tok):
                  continue
              if match(r'(.+::)?k[A-Z0-9]\w*', tok):
                  continue
              if match(r'(.+::)?[A-Z][A-Z0-9_]*', tok):
                  continue
              # A catch all for tricky sizeof cases, including 'sizeof expression',
              # 'sizeof(*type)', 'sizeof(const type)', 'sizeof(struct StructName)'
              # requires skipping the next token because we split on ' ' and '*'.
              if tok.startswith('sizeof'):
                  skip_next = True
                  continue
              is_const = False
              break
          if not is_const:
              error(line_number, 'runtime/arrays', 1,
                    'Do not use variable-length arrays.  Use an appropriately named '
                    "('k' followed by CamelCase) compile-time constant for the size.")
  
      # Check for use of unnamed namespaces in header files.  Registration
      # macros are typically OK, so we allow use of "namespace {" on lines
      # that end with backslashes.
      if (file_extension == 'h'
              and search(r'\bnamespace\s*{', line)
              and line[-1] != '\\'):
          error(line_number, 'build/namespaces', 4,
                'Do not use unnamed namespaces in header files.  See '
                'http://google-styleguide.googlecode.com/svn/trunk/cppguide.xml#Namespaces'
                ' for more information.')
  
      # Check for plain bitfields declared without either "singed" or "unsigned".
      # Most compilers treat such bitfields as signed, but there are still compilers like
      # RVCT 4.0 that use unsigned by default.
      matched = re.match(
          r'\s*((const|mutable)\s+)?(char|(short(\s+int)?)|int|long(\s+(long|int))?)\s+[a-zA-Z_][a-zA-Z0-9_]*\s*:\s*\d+\s*;', line)
      if matched:
          error(line_number, 'runtime/bitfields', 5,
                'Please declare integral type bitfields with either signed or unsigned.')
  
      check_identifier_name_in_declaration(filename, line_number, line, file_state, error)
  
      # Check for unsigned int (should be just 'unsigned')
      if search(r'\bunsigned int\b', line):
          error(line_number, 'runtime/unsigned', 1,
                'Omit int when using unsigned')
  
      # Check for usage of static_cast<Classname*>.
      check_for_object_static_cast(filename, line_number, line, error)
  
  
  def check_identifier_name_in_declaration(filename, line_number, line, file_state, error):
      """Checks if identifier names contain any underscores.
  
      As identifiers in libraries we are using have a bunch of
      underscores, we only warn about the declarations of identifiers
      and don't check use of identifiers.
  
      Args:
        filename: The name of the current file.
        line_number: The number of the line to check.
        line: The line of code to check.
        file_state: A _FileState instance which maintains information about
                    the state of things in the file.
        error: The function to call with any errors found.
      """
      # We don't check return and delete statements and conversion operator declarations.
      if match(r'\s*(return|delete|operator)\b', line):
          return
  
      # Basically, a declaration is a type name followed by whitespaces
      # followed by an identifier. The type name can be complicated
      # due to type adjectives and templates. We remove them first to
      # simplify the process to find declarations of identifiers.
  
      # Convert "long long", "long double", and "long long int" to
      # simple types, but don't remove simple "long".
      line = sub(r'long (long )?(?=long|double|int)', '', line)
      # Convert unsigned/signed types to simple types, too.
      line = sub(r'(unsigned|signed) (?=char|short|int|long)', '', line)
      line = sub(r'\b(inline|using|static|const|volatile|auto|register|extern|typedef|restrict|struct|class|virtual)(?=\W)', '', line)
  
      # Remove "new" and "new (expr)" to simplify, too.
      line = sub(r'new\s*(\([^)]*\))?', '', line)
  
      # Remove all template parameters by removing matching < and >.
      # Loop until no templates are removed to remove nested templates.
      while True:
          line, number_of_replacements = subn(r'<([\w\s:]|::)+\s*[*&]*\s*>', '', line)
          if not number_of_replacements:
              break
  
      # Declarations of local variables can be in condition expressions
      # of control flow statements (e.g., "if (LayoutObject* p = o->parent())").
      # We remove the keywords and the first parenthesis.
      #
      # Declarations in "while", "if", and "switch" are different from
      # other declarations in two aspects:
      #
      # - There can be only one declaration between the parentheses.
      #   (i.e., you cannot write "if (int i = 0, j = 1) {}")
      # - The variable must be initialized.
      #   (i.e., you cannot write "if (int i) {}")
      #
      # and we will need different treatments for them.
      line = sub(r'^\s*for\s*\(', '', line)
      line, control_statement = subn(r'^\s*(while|else if|if|switch)\s*\(', '', line)
  
      # Detect variable and functions.
      type_regexp = r'\w([\w]|\s*[*&]\s*|::)+'
      identifier_regexp = r'(?P<identifier>[\w:]+)'
      maybe_bitfield_regexp = r'(:\s*\d+\s*)?'
      character_after_identifier_regexp = r'(?P<character_after_identifier>[[;()=,])(?!=)'
      declaration_without_type_regexp = r'\s*' + identifier_regexp + \
          r'\s*' + maybe_bitfield_regexp + character_after_identifier_regexp
      declaration_with_type_regexp = r'\s*' + type_regexp + r'\s' + declaration_without_type_regexp
      is_function_arguments = False
      number_of_identifiers = 0
      while True:
          # If we are seeing the first identifier or arguments of a
          # function, there should be a type name before an identifier.
          if not number_of_identifiers or is_function_arguments:
              declaration_regexp = declaration_with_type_regexp
          else:
              declaration_regexp = declaration_without_type_regexp
  
          matched = match(declaration_regexp, line)
          if not matched:
              return
          identifier = matched.group('identifier')
          character_after_identifier = matched.group('character_after_identifier')
  
          # If we removed a non-for-control statement, the character after
          # the identifier should be '='. With this rule, we can avoid
          # warning for cases like "if (val & INT_MAX) {".
          if control_statement and character_after_identifier != '=':
              return
  
          is_function_arguments = is_function_arguments or character_after_identifier == '('
  
          # Remove "m_" and "s_" to allow them.
          modified_identifier = sub(r'(^|(?<=::))[ms]_', '', identifier)
          if not file_state.is_objective_c() and modified_identifier.find('_') >= 0:
              # Various exceptions to the rule: JavaScript op codes functions, const_iterator.
              if (not (filename.find('JavaScriptCore') >= 0 and modified_identifier.find('op_') >= 0)
                      and not (filename.find('gtk') >= 0 and modified_identifier.startswith('webkit_') >= 0)
                      and not modified_identifier.startswith('tst_')
                      and not modified_identifier.startswith('webkit_dom_object_')
                      and not modified_identifier.startswith('webkit_soup')
                      and not modified_identifier.startswith('NPN_')
                      and not modified_identifier.startswith('NPP_')
                      and not modified_identifier.startswith('NP_')
                      and not modified_identifier.startswith('qt_')
                      and not modified_identifier.startswith('_q_')
                      and not modified_identifier.startswith('cairo_')
                      and not modified_identifier.startswith('Ecore_')
                      and not modified_identifier.startswith('Eina_')
                      and not modified_identifier.startswith('Evas_')
                      and not modified_identifier.startswith('Ewk_')
                      and not modified_identifier.startswith('cti_')
                      and not modified_identifier.find('::qt_') >= 0
                      and not modified_identifier.find('::_q_') >= 0
                      and not modified_identifier == "const_iterator"
                      and not modified_identifier == "vm_throw"
                      and not modified_identifier == "DFG_OPERATION"):
                  error(line_number, 'readability/naming/underscores', 4, identifier +
                        " is incorrectly named. Don't use underscores in your identifier names.")
  
          # Check for variables named 'l', these are too easy to confuse with '1' in some fonts
          if modified_identifier == 'l':
              error(line_number, 'readability/naming', 4, identifier +
                    " is incorrectly named. Don't use the single letter 'l' as an identifier name.")
  
          # There can be only one declaration in non-for-control statements.
          if control_statement:
              return
          # We should continue checking if this is a function
          # declaration because we need to check its arguments.
          # Also, we need to check multiple declarations.
          if character_after_identifier != '(' and character_after_identifier != ',':
              return
  
          number_of_identifiers += 1
          line = line[matched.end():]
  
  
  def check_for_toFoo_definition(filename, pattern, error):
      """ Reports for using static_cast instead of toFoo convenience function.
  
      This function will output warnings to make sure you are actually using
      the added toFoo conversion functions rather than directly hard coding
      the static_cast<Classname*> call. For example, you should toHTMLELement(Node*)
      to convert Node* to HTMLElement*, instead of static_cast<HTMLElement*>(Node*)
  
      Args:
        filename: The name of the header file in which to check for toFoo definition.
        pattern: The conversion function pattern to grep for.
        error: The function to call with any errors found.
      """
      def get_abs_filepath(filename):
          fileSystem = FileSystem()
          base_dir = fileSystem.path_to_module(FileSystem.__module__).split('WebKit', 1)[0]
          base_dir = ''.join((base_dir, 'WebKit/Source'))
          for root, dirs, names in os.walk(base_dir):
              if filename in names:
                  return os.path.join(root, filename)
          return None
  
      def grep(lines, pattern, error):
          matches = []
          function_state = None
          for line_number in xrange(lines.num_lines()):
              line = (lines.elided[line_number]).rstrip()
              try:
                  if pattern in line:
                      if not function_state:
                          function_state = _FunctionState(1)
                      detect_functions(lines, line_number, function_state, error)
                      # Exclude the match of dummy conversion function. Dummy function is just to
                      # catch invalid conversions and shouldn't be part of possible alternatives.
                      result = re.search(r'%s(\s+)%s' % ("void", pattern), line)
                      if not result:
                          matches.append([line, function_state.body_start_position.row, function_state.end_position.row + 1])
                          function_state = None
              except UnicodeDecodeError:
                  # There would be no non-ascii characters in the codebase ever. The only exception
                  # would be comments/copyright text which might have non-ascii characters. Hence,
                  # it is perfectly safe to catch the UnicodeDecodeError and just pass the line.
                  pass
  
          return matches
  
      def check_in_mock_header(filename, matches=None):
          if not filename == 'Foo.h':
              return False
  
          header_file = None
          try:
              header_file = CppChecker.fs.read_text_file(filename)
          except IOError:
              return False
          line_number = 0
          for line in header_file:
              line_number += 1
              matched = re.search(r'\btoFoo\b', line)
              if matched:
                  matches.append(['toFoo', line_number, line_number + 3])
          return True
  
      # For unit testing only, avoid header search and lookup locally.
      matches = []
      mock_def_found = check_in_mock_header(filename, matches)
      if mock_def_found:
          return matches
  
      # Regular style check flow. Search for actual header file & defs.
      file_path = get_abs_filepath(filename)
      if not file_path:
          return None
      try:
          f = open(file_path)
          clean_lines = CleansedLines(f.readlines())
      finally:
          f.close()
  
      # Make a list of all genuine alternatives to static_cast.
      matches = grep(clean_lines, pattern, error)
      return matches
  
  
  def check_for_object_static_cast(processing_file, line_number, line, error):
      """Checks for a Cpp-style static cast on objects by looking for the pattern.
  
      Args:
        processing_file: The name of the processing file.
        line_number: The number of the line to check.
        line: The line of code to check.
        error: The function to call with any errors found.
      """
      matched = search(r'\bstatic_cast<(\s*\w*:?:?\w+\s*\*+\s*)>', line)
      if not matched:
          return
  
      class_name = re.sub('[\*]', '', matched.group(1))
      class_name = class_name.strip()
      # Ignore (for now) when the casting is to void*,
      if class_name == 'void':
          return
  
      namespace_pos = class_name.find(':')
      if not namespace_pos == -1:
          class_name = class_name[namespace_pos + 2:]
  
      header_file = ''.join((class_name, '.h'))
      matches = check_for_toFoo_definition(header_file, ''.join(('to', class_name)), error)
      # Ignore (for now) if not able to find the header where toFoo might be defined.
      # TODO: Handle cases where Classname might be defined in some other header or cpp file.
      if matches is None:
          return
  
      report_error = True
      # Ensure found static_cast instance is not from within toFoo definition itself.
      if os.path.basename(processing_file) == header_file:
          for item in matches:
              if line_number in range(item[1], item[2]):
                  report_error = False
                  break
  
      if report_error:
          if len(matches):
              # toFoo is defined - enforce using it.
              # TODO: Suggest an appropriate toFoo from the alternatives present in matches.
              error(line_number, 'runtime/casting', 4,
                    'static_cast of class objects is not allowed. Use to%s defined in %s.' %
                    (class_name, header_file))
          else:
              # No toFoo defined - enforce definition & usage.
              # TODO: Automate the generation of toFoo() to avoid any slippages ever.
              error(line_number, 'runtime/casting', 4,
                    'static_cast of class objects is not allowed. Add to%s in %s and use it instead.' %
                    (class_name, header_file))
  
  
  def check_c_style_cast(line_number, line, raw_line, cast_type, pattern,
                         error):
      """Checks for a C-style cast by looking for the pattern.
  
      This also handles sizeof(type) warnings, due to similarity of content.
  
      Args:
        line_number: The number of the line to check.
        line: The line of code to check.
        raw_line: The raw line of code to check, with comments.
        cast_type: The string for the C++ cast to recommend.  This is either
                   reinterpret_cast or static_cast, depending.
        pattern: The regular expression used to find C-style casts.
        error: The function to call with any errors found.
      """
      matched = search(pattern, line)
      if not matched:
          return
  
      # e.g., sizeof(int)
      sizeof_match = match(r'.*sizeof\s*$', line[0:matched.start(1) - 1])
      if sizeof_match:
          error(line_number, 'runtime/sizeof', 1,
                'Using sizeof(type).  Use sizeof(varname) instead if possible')
          return
  
      remainder = line[matched.end(0):]
  
      # The close paren is for function pointers as arguments to a function.
      # eg, void foo(void (*bar)(int));
      # The semicolon check is a more basic function check; also possibly a
      # function pointer typedef.
      # eg, void foo(int); or void foo(int) const;
      # The equals check is for function pointer assignment.
      # eg, void *(*foo)(int) = ...
      #
      # Right now, this will only catch cases where there's a single argument, and
      # it's unnamed.  It should probably be expanded to check for multiple
      # arguments with some unnamed.
      function_match = match(r'\s*(\)|=|(const)?\s*(;|\{|throw\(\)))', remainder)
      if function_match:
          if (not function_match.group(3)
                  or function_match.group(3) == ';'
                  or raw_line.find('/*') < 0):
              error(line_number, 'readability/function', 3,
                    'All parameters should be named in a function')
          return
  
      # At this point, all that should be left is actual casts.
      error(line_number, 'readability/casting', 4,
            'Using C-style cast.  Use %s<%s>(...) instead' %
            (cast_type, matched.group(1)))
  
  
  _HEADERS_CONTAINING_TEMPLATES = (
      ('<deque>', ('deque',)),
      ('<functional>', ('unary_function', 'binary_function',
                        'plus', 'minus', 'multiplies', 'divides', 'modulus',
                        'negate',
                        'equal_to', 'not_equal_to', 'greater', 'less',
                        'greater_equal', 'less_equal',
                        'logical_and', 'logical_or', 'logical_not',
                        'unary_negate', 'not1', 'binary_negate', 'not2',
                        'bind1st', 'bind2nd',
                        'pointer_to_unary_function',
                        'pointer_to_binary_function',
                        'ptr_fun',
                        'mem_fun_t', 'mem_fun', 'mem_fun1_t', 'mem_fun1_ref_t',
                        'mem_fun_ref_t',
                        'const_mem_fun_t', 'const_mem_fun1_t',
                        'const_mem_fun_ref_t', 'const_mem_fun1_ref_t',
                        'mem_fun_ref',
                        )),
      ('<limits>', ('numeric_limits',)),
      ('<list>', ('list',)),
      ('<map>', ('map', 'multimap',)),
      ('<memory>', ('allocator',)),
      ('<queue>', ('queue', 'priority_queue',)),
      ('<set>', ('set', 'multiset',)),
      ('<stack>', ('stack',)),
      ('<string>', ('char_traits', 'basic_string',)),
      ('<utility>', ('pair',)),
      ('<vector>', ('vector',)),
  
      # gcc extensions.
      # Note: std::hash is their hash, ::hash is our hash
      ('<hash_map>', ('hash_map', 'hash_multimap',)),
      ('<hash_set>', ('hash_set', 'hash_multiset',)),
      ('<slist>', ('slist',)),
  )
  
  _HEADERS_ACCEPTED_BUT_NOT_PROMOTED = {
      # We can trust with reasonable confidence that map gives us pair<>, too.
      'pair<>': ('map', 'multimap', 'hash_map', 'hash_multimap')
  }
  
  _RE_PATTERN_STRING = re.compile(r'\bstring\b')
  
  _re_pattern_algorithm_header = []
  for _template in ('copy', 'max', 'min', 'min_element', 'sort', 'swap',
                    'transform'):
      # Match max<type>(..., ...), max(..., ...), but not foo->max, foo.max or
      # type::max().
      _re_pattern_algorithm_header.append(
          (re.compile(r'[^>.]\b' + _template + r'(<.*?>)?\([^\)]'),
           _template,
           '<algorithm>'))
  
  _re_pattern_templates = []
  for _header, _templates in _HEADERS_CONTAINING_TEMPLATES:
      for _template in _templates:
          _re_pattern_templates.append(
              (re.compile(r'(\<|\b)' + _template + r'\s*\<'),
               _template + '<>',
               _header))
  
  
  def files_belong_to_same_module(filename_cpp, filename_h):
      """Check if these two filenames belong to the same module.
  
      The concept of a 'module' here is a as follows:
      foo.h, foo-inl.h, foo.cpp, foo_test.cpp and foo_unittest.cpp belong to the
      same 'module' if they are in the same directory.
      some/path/public/xyzzy and some/path/internal/xyzzy are also considered
      to belong to the same module here.
  
      If the filename_cpp contains a longer path than the filename_h, for example,
      '/absolute/path/to/base/sysinfo.cpp', and this file would include
      'base/sysinfo.h', this function also produces the prefix needed to open the
      header. This is used by the caller of this function to more robustly open the
      header file. We don't have access to the real include paths in this context,
      so we need this guesswork here.
  
      Known bugs: tools/base/bar.cpp and base/bar.h belong to the same module
      according to this implementation. Because of this, this function gives
      some false positives. This should be sufficiently rare in practice.
  
      Args:
        filename_cpp: is the path for the .cpp file
        filename_h: is the path for the header path
  
      Returns:
        Tuple with a bool and a string:
        bool: True if filename_cpp and filename_h belong to the same module.
        string: the additional prefix needed to open the header file.
      """
  
      if not filename_cpp.endswith('.cpp'):
          return (False, '')
      filename_cpp = filename_cpp[:-len('.cpp')]
      if filename_cpp.endswith('_unittest'):
          filename_cpp = filename_cpp[:-len('_unittest')]
      elif filename_cpp.endswith('_test'):
          filename_cpp = filename_cpp[:-len('_test')]
      filename_cpp = filename_cpp.replace('/public/', '/')
      filename_cpp = filename_cpp.replace('/internal/', '/')
  
      if not filename_h.endswith('.h'):
          return (False, '')
      filename_h = filename_h[:-len('.h')]
      if filename_h.endswith('-inl'):
          filename_h = filename_h[:-len('-inl')]
      filename_h = filename_h.replace('/public/', '/')
      filename_h = filename_h.replace('/internal/', '/')
  
      files_belong_to_same_module = filename_cpp.endswith(filename_h)
      common_path = ''
      if files_belong_to_same_module:
          common_path = filename_cpp[:-len(filename_h)]
      return files_belong_to_same_module, common_path
  
  
  def update_include_state(filename, include_state):
      """Fill up the include_state with new includes found from the file.
  
      Args:
        filename: the name of the header to read.
        include_state: an _IncludeState instance in which the headers are inserted.
        io: The io factory to use to read the file. Provided for testability.
  
      Returns:
        True if a header was succesfully added. False otherwise.
      """
      header_file = None
      try:
          header_file = CppChecker.fs.read_text_file(filename)
      except IOError:
          return False
      line_number = 0
      for line in header_file:
          line_number += 1
          clean_line = cleanse_comments(line)
          matched = _RE_PATTERN_INCLUDE.search(clean_line)
          if matched:
              include = matched.group(2)
              # The value formatting is cute, but not really used right now.
              # What matters here is that the key is in include_state.
              include_state.setdefault(include, '%s:%d' % (filename, line_number))
      return True
  
  
  def check_for_include_what_you_use(filename, clean_lines, include_state, error):
      """Reports for missing stl includes.
  
      This function will output warnings to make sure you are including the headers
      necessary for the stl containers and functions that you use. We only give one
      reason to include a header. For example, if you use both equal_to<> and
      less<> in a .h file, only one (the latter in the file) of these will be
      reported as a reason to include the <functional>.
  
      Args:
        filename: The name of the current file.
        clean_lines: A CleansedLines instance containing the file.
        include_state: An _IncludeState instance.
        error: The function to call with any errors found.
      """
      required = {}  # A map of header name to line_number and the template entity.
      # Example of required: { '<functional>': (1219, 'less<>') }
  
      for line_number in xrange(clean_lines.num_lines()):
          line = clean_lines.elided[line_number]
          if not line or line[0] == '#':
              continue
  
          # String is special -- it is a non-templatized type in STL.
          if _RE_PATTERN_STRING.search(line):
              required['<string>'] = (line_number, 'string')
  
          for pattern, template, header in _re_pattern_algorithm_header:
              if pattern.search(line):
                  required[header] = (line_number, template)
  
          # The following function is just a speed up, no semantics are changed.
          if not '<' in line:  # Reduces the cpu time usage by skipping lines.
              continue
  
          for pattern, template, header in _re_pattern_templates:
              if pattern.search(line):
                  required[header] = (line_number, template)
  
      # The policy is that if you #include something in foo.h you don't need to
      # include it again in foo.cpp. Here, we will look at possible includes.
      # Let's copy the include_state so it is only messed up within this function.
      include_state = include_state.copy()
  
      # Did we find the header for this file (if any) and succesfully load it?
      header_found = False
  
      # Use the absolute path so that matching works properly.
      abs_filename = os.path.abspath(filename)
  
      # For Emacs's flymake.
      # If cpp_style is invoked from Emacs's flymake, a temporary file is generated
      # by flymake and that file name might end with '_flymake.cpp'. In that case,
      # restore original file name here so that the corresponding header file can be
      # found.
      # e.g. If the file name is 'foo_flymake.cpp', we should search for 'foo.h'
      # instead of 'foo_flymake.h'
      abs_filename = re.sub(r'_flymake\.cpp$', '.cpp', abs_filename)
  
      # include_state is modified during iteration, so we iterate over a copy of
      # the keys.
      for header in include_state.keys():  # NOLINT
          (same_module, common_path) = files_belong_to_same_module(abs_filename, header)
          fullpath = common_path + header
          if same_module and update_include_state(fullpath, include_state):
              header_found = True
  
      # If we can't find the header file for a .cpp, assume it's because we don't
      # know where to look. In that case we'll give up as we're not sure they
      # didn't include it in the .h file.
      # FIXME: Do a better job of finding .h files so we are confident that
      #        not having the .h file means there isn't one.
      if filename.endswith('.cpp') and not header_found:
          return
  
      # All the lines have been processed, report the errors found.
      for required_header_unstripped in required:
          template = required[required_header_unstripped][1]
          if template in _HEADERS_ACCEPTED_BUT_NOT_PROMOTED:
              headers = _HEADERS_ACCEPTED_BUT_NOT_PROMOTED[template]
              if [True for header in headers if header in include_state]:
                  continue
          if required_header_unstripped.strip('<>"') not in include_state:
              error(required[required_header_unstripped][0],
                    'build/include_what_you_use', 4,
                    'Add #include ' + required_header_unstripped + ' for ' + template)
  
  
  def process_line(filename, file_extension,
                   clean_lines, line, include_state, function_state,
                   class_state, file_state, enum_state, error):
      """Processes a single line in the file.
  
      Args:
        filename: Filename of the file that is being processed.
        file_extension: The extension (dot not included) of the file.
        clean_lines: An array of strings, each representing a line of the file,
                     with comments stripped.
        line: Number of line being processed.
        include_state: An _IncludeState instance in which the headers are inserted.
        function_state: A _FunctionState instance which counts function lines, etc.
        class_state: A _ClassState instance which maintains information about
                     the current stack of nested class declarations being parsed.
        file_state: A _FileState instance which maintains information about
                    the state of things in the file.
        enum_state: A _EnumState instance which maintains an enum declaration
                    state.
        error: A callable to which errors are reported, which takes arguments:
               line number, error level, and message
  
      """
      raw_lines = clean_lines.raw_lines
      detect_functions(clean_lines, line, function_state, error)
      check_for_function_lengths(clean_lines, line, function_state, error)
      if search(r'\bNOLINT\b', raw_lines[line]):  # ignore nolint lines
          return
      if match(r'\s*\b__asm\b', raw_lines[line]):  # Ignore asm lines as they format differently.
          return
      check_function_definition(filename, file_extension, clean_lines, line, function_state, error)
      check_pass_ptr_usage(clean_lines, line, function_state, error)
      check_for_leaky_patterns(clean_lines, line, function_state, error)
      check_for_multiline_comments_and_strings(clean_lines, line, error)
      check_style(clean_lines, line, file_extension, class_state, file_state, enum_state, error)
      check_language(filename, clean_lines, line, file_extension, include_state,
                     file_state, error)
      check_for_non_standard_constructs(clean_lines, line, class_state, error)
      check_posix_threading(clean_lines, line, error)
      check_invalid_increment(clean_lines, line, error)
      check_conditional_and_loop_bodies_for_brace_violations(clean_lines, line, error)
      check_redundant_virtual(clean_lines, line, error)
      check_redundant_override(clean_lines, line, error)
  
  
  def _process_lines(filename, file_extension, lines, error, min_confidence):
      """Performs lint checks and reports any errors to the given error function.
  
      Args:
        filename: Filename of the file that is being processed.
        file_extension: The extension (dot not included) of the file.
        lines: An array of strings, each representing a line of the file, with the
               last element being empty if the file is terminated with a newline.
        error: A callable to which errors are reported, which takes 4 arguments:
      """
      lines = (['// marker so line numbers and indices both start at 1'] + lines +
               ['// marker so line numbers end in a known way'])
  
      include_state = _IncludeState()
      function_state = _FunctionState(min_confidence)
      class_state = _ClassState()
  
      check_for_copyright(lines, error)
  
      if file_extension == 'h':
          check_for_header_guard(filename, lines, error)
  
      remove_multi_line_comments(lines, error)
      clean_lines = CleansedLines(lines)
      file_state = _FileState(clean_lines, file_extension)
      enum_state = _EnumState()
      for line in xrange(clean_lines.num_lines()):
          process_line(filename, file_extension, clean_lines, line,
                       include_state, function_state, class_state, file_state,
                       enum_state, error)
      class_state.check_finished(error)
  
      check_for_include_what_you_use(filename, clean_lines, include_state, error)
  
      # We check here rather than inside process_line so that we see raw
      # lines rather than "cleaned" lines.
      check_for_unicode_replacement_characters(lines, error)
  
      check_for_new_line_at_eof(lines, error)
  
  
  class CppChecker(object):
  
      """Processes C++ lines for checking style."""
  
      # This list is used to--
      #
      # (1) generate an explicit list of all possible categories,
      # (2) unit test that all checked categories have valid names, and
      # (3) unit test that all categories are getting unit tested.
      #
      categories = set([
          'build/class',
          'build/deprecated',
          'build/endif_comment',
          'build/forward_decl',
          'build/header_guard',
          'build/include',
          'build/include_order',
          'build/include_what_you_use',
          'build/namespaces',
          'build/printf_format',
          'build/storage_class',
          'build/using_std',
          'legal/copyright',
          'readability/braces',
          'readability/casting',
          'readability/check',
          'readability/comparison_to_boolean',
          'readability/constructors',
          'readability/control_flow',
          'readability/enum_casing',
          'readability/fn_size',
          'readability/function',
          'readability/inheritance',
          'readability/multiline_comment',
          'readability/multiline_string',
          'readability/parameter_name',
          'readability/naming',
          'readability/naming/underscores',
          'readability/null',
          'readability/pass_ptr',
          'readability/streams',
          'readability/templatebrackets',
          'readability/todo',
          'readability/utf8',
          'readability/webkit_export',
          'runtime/arrays',
          'runtime/bitfields',
          'runtime/casting',
          'runtime/ctype_function',
          'runtime/explicit',
          'runtime/init',
          'runtime/int',
          'runtime/invalid_increment',
          'runtime/leaky_pattern',
          'runtime/max_min_macros',
          'runtime/memset',
          'runtime/printf',
          'runtime/printf_format',
          'runtime/references',
          'runtime/rtti',
          'runtime/sizeof',
          'runtime/string',
          'runtime/threadsafe_fn',
          'runtime/unsigned',
          'runtime/virtual',
          'whitespace/blank_line',
          'whitespace/braces',
          'whitespace/comma',
          'whitespace/comments',
          'whitespace/declaration',
          'whitespace/end_of_line',
          'whitespace/ending_newline',
          'whitespace/indent',
          'whitespace/line_length',
          'whitespace/newline',
          'whitespace/operators',
          'whitespace/parens',
          'whitespace/semicolon',
          'whitespace/tab',
          'whitespace/todo',
      ])
  
      fs = None
  
      def __init__(self, file_path, file_extension, handle_style_error,
                   min_confidence, fs=None):
          """Create a CppChecker instance.
  
          Args:
            file_extension: A string that is the file extension, without
                            the leading dot.
  
          """
          self.file_extension = file_extension
          self.file_path = file_path
          self.handle_style_error = handle_style_error
          self.min_confidence = min_confidence
          CppChecker.fs = fs or FileSystem()
  
      # Useful for unit testing.
      def __eq__(self, other):
          """Return whether this CppChecker instance is equal to another."""
          if self.file_extension != other.file_extension:
              return False
          if self.file_path != other.file_path:
              return False
          if self.handle_style_error != other.handle_style_error:
              return False
          if self.min_confidence != other.min_confidence:
              return False
  
          return True
  
      # Useful for unit testing.
      def __ne__(self, other):
          # Python does not automatically deduce __ne__() from __eq__().
          return not self.__eq__(other)
  
      def check(self, lines):
          _process_lines(self.file_path, self.file_extension, lines,
                         self.handle_style_error, self.min_confidence)
  
  
  # FIXME: Remove this function (requires refactoring unit tests).
  def process_file_data(filename, file_extension, lines, error, min_confidence, fs=None):
      checker = CppChecker(filename, file_extension, error, min_confidence, fs)
      checker.check(lines)
  