Refactoring and update.

1 files changed, 6323 insertions, 0 deletions

diff --git a/CMakeModules/cpplint.py b/CMakeModules/cpplint.py
new file mode 100755
index 0000000..ccc25d4
--- /dev/null
+++ b/CMakeModules/cpplint.py
@@ -0,0 +1,6323 @@
+#!/usr/bin/env python
+#
+# Copyright (c) 2009 Google Inc. All rights reserved.
+#
+# 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.
+
+"""Does google-lint on c++ files.
+
+The goal of this script is to identify places in the code that *may*
+be in non-compliance with google style.  It does not attempt to fix
+up these problems -- the point is to educate.  It does also not
+attempt to find all problems, or to ensure that everything it does
+find is legitimately a problem.
+
+In particular, we can get very confused by /* and // inside strings!
+We do a small hack, which is to ignore //'s with "'s after them on the
+same line, but it is far from perfect (in either direction).
+"""
+
+import codecs
+import copy
+import getopt
+import math  # for log
+import os
+import re
+import sre_compile
+import string
+import sys
+import unicodedata
+
+
+_USAGE = """
+Syntax: cpplint.py [--verbose=#] [--output=vs7] [--filter=-x,+y,...]
+                   [--counting=total|toplevel|detailed] [--root=subdir]
+                   [--linelength=digits]
+        <file> [file] ...
+
+  The style guidelines this tries to follow are those in
+    http://google-styleguide.googlecode.com/svn/trunk/cppguide.xml
+
+  Every problem is given a confidence score from 1-5, with 5 meaning we are
+  certain of the problem, and 1 meaning it could be a legitimate construct.
+  This will miss some errors, and is not a substitute for a code review.
+
+  To suppress false-positive errors of a certain category, add a
+  'NOLINT(category)' comment to the line.  NOLINT or NOLINT(*)
+  suppresses errors of all categories on that line.
+
+  The files passed in will be linted; at least one file must be provided.
+  Default linted extensions are .cc, .cpp, .cu, .cuh and .h.  Change the
+  extensions with the --extensions flag.
+
+  Flags:
+
+    output=vs7
+      By default, the output is formatted to ease emacs parsing.  Visual Studio
+      compatible output (vs7) may also be used.  Other formats are unsupported.
+
+    verbose=#
+      Specify a number 0-5 to restrict errors to certain verbosity levels.
+
+    filter=-x,+y,...
+      Specify a comma-separated list of category-filters to apply: only
+      error messages whose category names pass the filters will be printed.
+      (Category names are printed with the message and look like
+      "[whitespace/indent]".)  Filters are evaluated left to right.
+      "-FOO" and "FOO" means "do not print categories that start with FOO".
+      "+FOO" means "do print categories that start with FOO".
+
+      Examples: --filter=-whitespace,+whitespace/braces
+                --filter=whitespace,runtime/printf,+runtime/printf_format
+                --filter=-,+build/include_what_you_use
+
+      To see a list of all the categories used in cpplint, pass no arg:
+         --filter=
+
+    counting=total|toplevel|detailed
+      The total number of errors found is always printed. If
+      'toplevel' is provided, then the count of errors in each of
+      the top-level categories like 'build' and 'whitespace' will
+      also be printed. If 'detailed' is provided, then a count
+      is provided for each category like 'build/class'.
+
+    root=subdir
+      The root directory used for deriving header guard CPP variable.
+      By default, the header guard CPP variable is calculated as the relative
+      path to the directory that contains .git, .hg, or .svn.  When this flag
+      is specified, the relative path is calculated from the specified
+      directory. If the specified directory does not exist, this flag is
+      ignored.
+
+      Examples:
+        Assuming that src/.git exists, the header guard CPP variables for
+        src/chrome/browser/ui/browser.h are:
+
+        No flag => CHROME_BROWSER_UI_BROWSER_H_
+        --root=chrome => BROWSER_UI_BROWSER_H_
+        --root=chrome/browser => UI_BROWSER_H_
+
+    linelength=digits
+      This is the allowed line length for the project. The default value is
+      80 characters.
+
+      Examples:
+        --linelength=120
+
+    extensions=extension,extension,...
+      The allowed file extensions that cpplint will check
+
+      Examples:
+        --extensions=hpp,cpp
+
+    cpplint.py supports per-directory configurations specified in CPPLINT.cfg
+    files. CPPLINT.cfg file can contain a number of key=value pairs.
+    Currently the following options are supported:
+
+      set noparent
+      filter=+filter1,-filter2,...
+      exclude_files=regex
+      linelength=80
+
+    "set noparent" option prevents cpplint from traversing directory tree
+    upwards looking for more .cfg files in parent directories. This option
+    is usually placed in the top-level project directory.
+
+    The "filter" option is similar in function to --filter flag. It specifies
+    message filters in addition to the |_DEFAULT_FILTERS| and those specified
+    through --filter command-line flag.
+
+    "exclude_files" allows to specify a regular expression to be matched against
+    a file name. If the expression matches, the file is skipped and not run
+    through liner.
+
+    "linelength" allows to specify the allowed line length for the project.
+
+    CPPLINT.cfg has an effect on files in the same directory and all
+    sub-directories, unless overridden by a nested configuration file.
+
+      Example file:
+        filter=-build/include_order,+build/include_alpha
+        exclude_files=.*\.cc
+
+    The above example disables build/include_order warning and enables
+    build/include_alpha as well as excludes all .cc from being
+    processed by linter, in the current directory (where the .cfg
+    file is located) and all sub-directories.
+"""
+
+# We categorize each error message we print.  Here are the categories.
+# We want an explicit list so we can list them all in cpplint --filter=.
+# If you add a new error message with a new category, add it to the list
+# here!  cpplint_unittest.py should tell you if you forget to do this.
+_ERROR_CATEGORIES = [
+    'build/class',
+    'build/c++11',
+    'build/deprecated',
+    'build/endif_comment',
+    'build/explicit_make_pair',
+    'build/forward_decl',
+    'build/header_guard',
+    'build/include',
+    'build/include_alpha',
+    'build/include_order',
+    'build/include_what_you_use',
+    'build/namespaces',
+    'build/printf_format',
+    'build/storage_class',
+    'legal/copyright',
+    'readability/alt_tokens',
+    'readability/braces',
+    'readability/casting',
+    'readability/check',
+    'readability/constructors',
+    'readability/fn_size',
+    'readability/function',
+    'readability/inheritance',
+    'readability/multiline_comment',
+    'readability/multiline_string',
+    'readability/namespace',
+    'readability/nolint',
+    'readability/nul',
+    'readability/strings',
+    'readability/todo',
+    'readability/utf8',
+    'runtime/arrays',
+    'runtime/casting',
+    'runtime/explicit',
+    'runtime/int',
+    'runtime/init',
+    'runtime/invalid_increment',
+    'runtime/member_string_references',
+    'runtime/memset',
+    'runtime/indentation_namespace',
+    'runtime/operator',
+    'runtime/printf',
+    'runtime/printf_format',
+    'runtime/references',
+    'runtime/string',
+    'runtime/threadsafe_fn',
+    'runtime/vlog',
+    'whitespace/blank_line',
+    'whitespace/braces',
+    'whitespace/comma',
+    'whitespace/comments',
+    'whitespace/empty_conditional_body',
+    'whitespace/empty_loop_body',
+    'whitespace/end_of_line',
+    'whitespace/ending_newline',
+    'whitespace/forcolon',
+    'whitespace/indent',
+    'whitespace/line_length',
+    'whitespace/newline',
+    'whitespace/operators',
+    'whitespace/parens',
+    'whitespace/semicolon',
+    'whitespace/tab',
+    'whitespace/todo',
+    ]
+
+# These error categories are no longer enforced by cpplint, but for backwards-
+# compatibility they may still appear in NOLINT comments.
+_LEGACY_ERROR_CATEGORIES = [
+    'readability/streams',
+    ]
+
+# The default state of the category filter. This is overridden by the --filter=
+# flag. By default all errors are on, so only add here categories that should be
+# off by default (i.e., categories that must be enabled by the --filter= flags).
+# All entries here should start with a '-' or '+', as in the --filter= flag.
+_DEFAULT_FILTERS = ['-build/include_alpha']
+
+# We used to check for high-bit characters, but after much discussion we
+# decided those were OK, as long as they were in UTF-8 and didn't represent
+# hard-coded international strings, which belong in a separate i18n file.
+
+# C++ headers
+_CPP_HEADERS = frozenset([
+    # Legacy
+    'algobase.h',
+    'algo.h',
+    'alloc.h',
+    'builtinbuf.h',
+    'bvector.h',
+    'complex.h',
+    'defalloc.h',
+    'deque.h',
+    'editbuf.h',
+    'fstream.h',
+    'function.h',
+    'hash_map',
+    'hash_map.h',
+    'hash_set',
+    'hash_set.h',
+    'hashtable.h',
+    'heap.h',
+    'indstream.h',
+    'iomanip.h',
+    'iostream.h',
+    'istream.h',
+    'iterator.h',
+    'list.h',
+    'map.h',
+    'multimap.h',
+    'multiset.h',
+    'ostream.h',
+    'pair.h',
+    'parsestream.h',
+    'pfstream.h',
+    'procbuf.h',
+    'pthread_alloc',
+    'pthread_alloc.h',
+    'rope',
+    'rope.h',
+    'ropeimpl.h',
+    'set.h',
+    'slist',
+    'slist.h',
+    'stack.h',
+    'stdiostream.h',
+    'stl_alloc.h',
+    'stl_relops.h',
+    'streambuf.h',
+    'stream.h',
+    'strfile.h',
+    'strstream.h',
+    'tempbuf.h',
+    'tree.h',
+    'type_traits.h',
+    'vector.h',
+    # 17.6.1.2 C++ library headers
+    'algorithm',
+    'array',
+    'atomic',
+    'bitset',
+    'chrono',
+    'codecvt',
+    'complex',
+    'condition_variable',
+    'deque',
+    'exception',
+    'forward_list',
+    'fstream',
+    'functional',
+    'future',
+    'initializer_list',
+    'iomanip',
+    'ios',
+    'iosfwd',
+    'iostream',
+    'istream',
+    'iterator',
+    'limits',
+    'list',
+    'locale',
+    'map',
+    'memory',
+    'mutex',
+    'new',
+    'numeric',
+    'ostream',
+    'queue',
+    'random',
+    'ratio',
+    'regex',
+    'set',
+    'sstream',
+    'stack',
+    'stdexcept',
+    'streambuf',
+    'string',
+    'strstream',
+    'system_error',
+    'thread',
+    'tuple',
+    'typeindex',
+    'typeinfo',
+    'type_traits',
+    'unordered_map',
+    'unordered_set',
+    'utility',
+    'valarray',
+    'vector',
+    # 17.6.1.2 C++ headers for C library facilities
+    'cassert',
+    'ccomplex',
+    'cctype',
+    'cerrno',
+    'cfenv',
+    'cfloat',
+    'cinttypes',
+    'ciso646',
+    'climits',
+    'clocale',
+    'cmath',
+    'csetjmp',
+    'csignal',
+    'cstdalign',
+    'cstdarg',
+    'cstdbool',
+    'cstddef',
+    'cstdint',
+    'cstdio',
+    'cstdlib',
+    'cstring',
+    'ctgmath',
+    'ctime',
+    'cuchar',
+    'cwchar',
+    'cwctype',
+    ])
+
+
+# These headers are excluded from [build/include] and [build/include_order]
+# checks:
+# - Anything not following google file name conventions (containing an
+#   uppercase character, such as Python.h or nsStringAPI.h, for example).
+# - Lua headers.
+_THIRD_PARTY_HEADERS_PATTERN = re.compile(
+    r'^(?:[^/]*[A-Z][^/]*\.h|lua\.h|lauxlib\.h|lualib\.h)$')
+
+
+# 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
+
+# Alternative tokens and their replacements.  For full list, see section 2.5
+# Alternative tokens [lex.digraph] in the C++ standard.
+#
+# Digraphs (such as '%:') are not included here since it's a mess to
+# match those on a word boundary.
+_ALT_TOKEN_REPLACEMENT = {
+    'and': '&&',
+    'bitor': '|',
+    'or': '||',
+    'xor': '^',
+    'compl': '~',
+    'bitand': '&',
+    'and_eq': '&=',
+    'or_eq': '|=',
+    'xor_eq': '^=',
+    'not': '!',
+    'not_eq': '!='
+    }
+
+# Compile regular expression that matches all the above keywords.  The "[ =()]"
+# bit is meant to avoid matching these keywords outside of boolean expressions.
+#
+# False positives include C-style multi-line comments and multi-line strings
+# but those have always been troublesome for cpplint.
+_ALT_TOKEN_REPLACEMENT_PATTERN = re.compile(
+    r'[ =()](' + ('|'.join(_ALT_TOKEN_REPLACEMENT.keys())) + r')(?=[ (]|$)')
+
+
+# These constants define types of headers for use with
+# _IncludeState.CheckNextIncludeOrder().
+_C_SYS_HEADER = 1
+_CPP_SYS_HEADER = 2
+_LIKELY_MY_HEADER = 3
+_POSSIBLE_MY_HEADER = 4
+_OTHER_HEADER = 5
+
+# These constants define the current inline assembly state
+_NO_ASM = 0       # Outside of inline assembly block
+_INSIDE_ASM = 1   # Inside inline assembly block
+_END_ASM = 2      # Last line of inline assembly block
+_BLOCK_ASM = 3    # The whole block is an inline assembly block
+
+# Match start of assembly blocks
+_MATCH_ASM = re.compile(r'^\s*(?:asm|_asm|__asm|__asm__)'
+                        r'(?:\s+(volatile|__volatile__))?'
+                        r'\s*[{(]')
+
+
+_regexp_compile_cache = {}
+
+# {str, set(int)}: a map from error categories to sets of linenumbers
+# on which those errors are expected and should be suppressed.
+_error_suppressions = {}
+
+# The root directory used for deriving header guard CPP variable.
+# This is set by --root flag.
+_root = None
+
+# The allowed line length of files.
+# This is set by --linelength flag.
+_line_length = 80
+
+# The allowed extensions for file names
+# This is set by --extensions flag.
+_valid_extensions = set(['cc', 'h', 'cpp', 'cu', 'cuh'])
+
+def ParseNolintSuppressions(filename, raw_line, linenum, error):
+  """Updates the global list of error-suppressions.
+
+  Parses any NOLINT comments on the current line, updating the global
+  error_suppressions store.  Reports an error if the NOLINT comment
+  was malformed.
+
+  Args:
+    filename: str, the name of the input file.
+    raw_line: str, the line of input text, with comments.
+    linenum: int, the number of the current line.
+    error: function, an error handler.
+  """
+  matched = Search(r'\bNOLINT(NEXTLINE)?\b(\([^)]+\))?', raw_line)
+  if matched:
+    if matched.group(1):
+      suppressed_line = linenum + 1
+    else:
+      suppressed_line = linenum
+    category = matched.group(2)
+    if category in (None, '(*)'):  # => "suppress all"
+      _error_suppressions.setdefault(None, set()).add(suppressed_line)
+    else:
+      if category.startswith('(') and category.endswith(')'):
+        category = category[1:-1]
+        if category in _ERROR_CATEGORIES:
+          _error_suppressions.setdefault(category, set()).add(suppressed_line)
+        elif category not in _LEGACY_ERROR_CATEGORIES:
+          error(filename, linenum, 'readability/nolint', 5,
+                'Unknown NOLINT error category: %s' % category)
+
+
+def ResetNolintSuppressions():
+  """Resets the set of NOLINT suppressions to empty."""
+  _error_suppressions.clear()
+
+
+def IsErrorSuppressedByNolint(category, linenum):
+  """Returns true if the specified error category is suppressed on this line.
+
+  Consults the global error_suppressions map populated by
+  ParseNolintSuppressions/ResetNolintSuppressions.
+
+  Args:
+    category: str, the category of the error.
+    linenum: int, the current line number.
+  Returns:
+    bool, True iff the error should be suppressed due to a NOLINT comment.
+  """
+  return (linenum in _error_suppressions.get(category, set()) or
+          linenum in _error_suppressions.get(None, set()))
+
+
+def Match(pattern, s):
+  """Matches the string with the pattern, caching the compiled regexp."""
+  # The regexp compilation caching is inlined in both Match and Search for
+  # performance reasons; factoring it out into a separate function turns out
+  # to be noticeably expensive.
+  if pattern not in _regexp_compile_cache:
+    _regexp_compile_cache[pattern] = sre_compile.compile(pattern)
+  return _regexp_compile_cache[pattern].match(s)
+
+
+def ReplaceAll(pattern, rep, s):
+  """Replaces instances of pattern in a string with a replacement.
+
+  The compiled regex is kept in a cache shared by Match and Search.
+
+  Args:
+    pattern: regex pattern
+    rep: replacement text
+    s: search string
+
+  Returns:
+    string with replacements made (or original string if no replacements)
+  """
+  if pattern not in _regexp_compile_cache:
+    _regexp_compile_cache[pattern] = sre_compile.compile(pattern)
+  return _regexp_compile_cache[pattern].sub(rep, s)
+
+
+def Search(pattern, s):
+  """Searches the string for the pattern, caching the compiled regexp."""
+  if pattern not in _regexp_compile_cache:
+    _regexp_compile_cache[pattern] = sre_compile.compile(pattern)
+  return _regexp_compile_cache[pattern].search(s)
+
+
+class _IncludeState(object):
+  """Tracks line numbers for includes, and the order in which includes appear.
+
+  include_list contains list of lists of (header, line number) pairs.
+  It's a lists of lists rather than just one flat list to make it
+  easier to update across preprocessor boundaries.
+
+  Call CheckNextIncludeOrder() 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, CheckNextIncludeOrder will raise an error.
+  _INITIAL_SECTION = 0
+  _MY_H_SECTION = 1
+  _C_SECTION = 2
+  _CPP_SECTION = 3
+  _OTHER_H_SECTION = 4
+
+  _TYPE_NAMES = {
+      _C_SYS_HEADER: 'C system header',
+      _CPP_SYS_HEADER: 'C++ system header',
+      _LIKELY_MY_HEADER: 'header this file implements',
+      _POSSIBLE_MY_HEADER: 'header this file may implement',
+      _OTHER_HEADER: 'other header',
+      }
+  _SECTION_NAMES = {
+      _INITIAL_SECTION: "... nothing. (This can't be an error.)",
+      _MY_H_SECTION: 'a header this file implements',
+      _C_SECTION: 'C system header',
+      _CPP_SECTION: 'C++ system header',
+      _OTHER_H_SECTION: 'other header',
+      }
+
+  def __init__(self):
+    self.include_list = [[]]
+    self.ResetSection('')
+
+  def FindHeader(self, header):
+    """Check if a header has already been included.
+
+    Args:
+      header: header to check.
+    Returns:
+      Line number of previous occurrence, or -1 if the header has not
+      been seen before.
+    """
+    for section_list in self.include_list:
+      for f in section_list:
+        if f[0] == header:
+          return f[1]
+    return -1
+
+  def ResetSection(self, directive):
+    """Reset section checking for preprocessor directive.
+
+    Args:
+      directive: preprocessor directive (e.g. "if", "else").
+    """
+    # The name of the current section.
+    self._section = self._INITIAL_SECTION
+    # The path of last found header.
+    self._last_header = ''
+
+    # Update list of includes.  Note that we never pop from the
+    # include list.
+    if directive in ('if', 'ifdef', 'ifndef'):
+      self.include_list.append([])
+    elif directive in ('else', 'elif'):
+      self.include_list[-1] = []
+
+  def SetLastHeader(self, header_path):
+    self._last_header = header_path
+
+  def CanonicalizeAlphabeticalOrder(self, header_path):
+    """Returns a path canonicalized for alphabetical comparison.
+
+    - replaces "-" with "_" so they both cmp the same.
+    - removes '-inl' since we don't require them to be after the main header.
+    - lowercase everything, just in case.
+
+    Args:
+      header_path: Path to be canonicalized.
+
+    Returns:
+      Canonicalized path.
+    """
+    return header_path.replace('-inl.h', '.h').replace('-', '_').lower()
+
+  def IsInAlphabeticalOrder(self, clean_lines, linenum, header_path):
+    """Check if a header is in alphabetical order with the previous header.
+
+    Args:
+      clean_lines: A CleansedLines instance containing the file.
+      linenum: The number of the line to check.
+      header_path: Canonicalized header to be checked.
+
+    Returns:
+      Returns true if the header is in alphabetical order.
+    """
+    # If previous section is different from current section, _last_header will
+    # be reset to empty string, so it's always less than current header.
+    #
+    # If previous line was a blank line, assume that the headers are
+    # intentionally sorted the way they are.
+    if (self._last_header > header_path and
+        Match(r'^\s*#\s*include\b', clean_lines.elided[linenum - 1])):
+      return False
+    return True
+
+  def CheckNextIncludeOrder(self, header_type):
+    """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.
+
+    Returns:
+      The empty string if the header is in the right order, or an
+      error message describing what's wrong.
+
+    """
+    error_message = ('Found %s after %s' %
+                     (self._TYPE_NAMES[header_type],
+                      self._SECTION_NAMES[self._section]))
+
+    last_section = self._section
+
+    if header_type == _C_SYS_HEADER:
+      if self._section <= self._C_SECTION:
+        self._section = self._C_SECTION
+      else:
+        self._last_header = ''
+        return error_message
+    elif header_type == _CPP_SYS_HEADER:
+      if self._section <= self._CPP_SECTION:
+        self._section = self._CPP_SECTION
+      else:
+        self._last_header = ''
+        return error_message
+    elif header_type == _LIKELY_MY_HEADER:
+      if self._section <= self._MY_H_SECTION:
+        self._section = self._MY_H_SECTION
+      else:
+        self._section = self._OTHER_H_SECTION
+    elif header_type == _POSSIBLE_MY_HEADER:
+      if self._section <= self._MY_H_SECTION:
+        self._section = self._MY_H_SECTION
+      else:
+        # This will always be the fallback because we're not sure
+        # enough that the header is associated with this file.
+        self._section = self._OTHER_H_SECTION
+    else:
+      assert header_type == _OTHER_HEADER
+      self._section = self._OTHER_H_SECTION
+
+    if last_section != self._section:
+      self._last_header = ''
+
+    return ''
+
+
+class _CppLintState(object):
+  """Maintains module-wide state.."""
+
+  def __init__(self):
+    self.verbose_level = 1  # global setting.
+    self.error_count = 0    # global count of reported errors
+    # filters to apply when emitting error messages
+    self.filters = _DEFAULT_FILTERS[:]
+    # backup of filter list. Used to restore the state after each file.
+    self._filters_backup = self.filters[:]
+    self.counting = 'total'  # In what way are we counting errors?
+    self.errors_by_category = {}  # string to int dict storing error counts
+
+    # output format:
+    # "emacs" - format that emacs can parse (default)
+    # "vs7" - format that Microsoft Visual Studio 7 can parse
+    self.output_format = 'emacs'
+
+  def SetOutputFormat(self, output_format):
+    """Sets the output format for errors."""
+    self.output_format = output_format
+
+  def SetVerboseLevel(self, level):
+    """Sets the module's verbosity, and returns the previous setting."""
+    last_verbose_level = self.verbose_level
+    self.verbose_level = level
+    return last_verbose_level
+
+  def SetCountingStyle(self, counting_style):
+    """Sets the module's counting options."""
+    self.counting = counting_style
+
+  def SetFilters(self, filters):
+    """Sets the error-message filters.
+
+    These filters are applied when deciding whether to emit a given
+    error message.
+
+    Args:
+      filters: A string of comma-separated filters (eg "+whitespace/indent").
+               Each filter should start with + or -; else we die.
+
+    Raises:
+      ValueError: The comma-separated filters did not all start with '+' or '-'.
+                  E.g. "-,+whitespace,-whitespace/indent,whitespace/badfilter"
+    """
+    # Default filters always have less priority than the flag ones.
+    self.filters = _DEFAULT_FILTERS[:]
+    self.AddFilters(filters)
+
+  def AddFilters(self, filters):
+    """ Adds more filters to the existing list of error-message filters. """
+    for filt in filters.split(','):
+      clean_filt = filt.strip()
+      if clean_filt:
+        self.filters.append(clean_filt)
+    for filt in self.filters:
+      if not (filt.startswith('+') or filt.startswith('-')):
+        raise ValueError('Every filter in --filters must start with + or -'
+                         ' (%s does not)' % filt)
+
+  def BackupFilters(self):
+    """ Saves the current filter list to backup storage."""
+    self._filters_backup = self.filters[:]
+
+  def RestoreFilters(self):
+    """ Restores filters previously backed up."""
+    self.filters = self._filters_backup[:]
+
+  def ResetErrorCounts(self):
+    """Sets the module's error statistic back to zero."""
+    self.error_count = 0
+    self.errors_by_category = {}
+
+  def IncrementErrorCount(self, category):
+    """Bumps the module's error statistic."""
+    self.error_count += 1
+    if self.counting in ('toplevel', 'detailed'):
+      if self.counting != 'detailed':
+        category = category.split('/')[0]
+      if category not in self.errors_by_category:
+        self.errors_by_category[category] = 0
+      self.errors_by_category[category] += 1
+
+  def PrintErrorCounts(self):
+    """Print a summary of errors by category, and the total."""
+    for category, count in self.errors_by_category.iteritems():
+      sys.stderr.write('Category \'%s\' errors found: %d\n' %
+                       (category, count))
+    sys.stderr.write('Total errors found: %d\n' % self.error_count)
+
+_cpplint_state = _CppLintState()
+
+
+def _OutputFormat():
+  """Gets the module's output format."""
+  return _cpplint_state.output_format
+
+
+def _SetOutputFormat(output_format):
+  """Sets the module's output format."""
+  _cpplint_state.SetOutputFormat(output_format)
+
+
+def _VerboseLevel():
+  """Returns the module's verbosity setting."""
+  return _cpplint_state.verbose_level
+
+
+def _SetVerboseLevel(level):
+  """Sets the module's verbosity, and returns the previous setting."""
+  return _cpplint_state.SetVerboseLevel(level)
+
+
+def _SetCountingStyle(level):
+  """Sets the module's counting options."""
+  _cpplint_state.SetCountingStyle(level)
+
+
+def _Filters():
+  """Returns the module's list of output filters, as a list."""
+  return _cpplint_state.filters
+
+
+def _SetFilters(filters):
+  """Sets the module's error-message filters.
+
+  These filters are applied when deciding whether to emit a given
+  error message.
+
+  Args:
+    filters: A string of comma-separated filters (eg "whitespace/indent").
+             Each filter should start with + or -; else we die.
+  """
+  _cpplint_state.SetFilters(filters)
+
+def _AddFilters(filters):
+  """Adds more filter overrides.
+
+  Unlike _SetFilters, this function does not reset the current list of filters
+  available.
+
+  Args:
+    filters: A string of comma-separated filters (eg "whitespace/indent").
+             Each filter should start with + or -; else we die.
+  """
+  _cpplint_state.AddFilters(filters)
+
+def _BackupFilters():
+  """ Saves the current filter list to backup storage."""
+  _cpplint_state.BackupFilters()
+
+def _RestoreFilters():
+  """ Restores filters previously backed up."""
+  _cpplint_state.RestoreFilters()
+
+class _FunctionState(object):
+  """Tracks current function name and the number of lines in its body."""
+
+  _NORMAL_TRIGGER = 250  # for --v=0, 500 for --v=1, etc.
+  _TEST_TRIGGER = 400    # about 50% more than _NORMAL_TRIGGER.
+
+  def __init__(self):
+    self.in_a_function = False
+    self.lines_in_function = 0
+    self.current_function = ''
+
+  def Begin(self, function_name):
+    """Start analyzing function body.
+
+    Args:
+      function_name: The name of the function being tracked.
+    """
+    self.in_a_function = True
+    self.lines_in_function = 0
+    self.current_function = function_name
+
+  def Count(self):
+    """Count line in current function body."""
+    if self.in_a_function:
+      self.lines_in_function += 1
+
+  def Check(self, error, filename, linenum):
+    """Report if too many lines in function body.
+
+    Args:
+      error: The function to call with any errors found.
+      filename: The name of the current file.
+      linenum: 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**_VerboseLevel()
+
+    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(filename, linenum, '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(object):
+  """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 FullName(self):
+    """Make Windows paths like Unix."""
+    return os.path.abspath(self._filename).replace('\\', '/')
+
+  def RepositoryName(self):
+    """FullName 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.FullName()
+
+    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 <= 1.6? Try to find a git, hg, or svn 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")) and
+             not os.path.exists(os.path.join(root_dir, ".hg")) and
+             not os.path.exists(os.path.join(root_dir, ".svn"))):
+        root_dir = os.path.dirname(root_dir)
+
+      if (os.path.exists(os.path.join(root_dir, ".git")) or
+          os.path.exists(os.path.join(root_dir, ".hg")) or
+          os.path.exists(os.path.join(root_dir, ".svn"))):
+        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.cc', Split() would
+    return ('chrome/browser', 'browser', '.cc')
+
+    Returns:
+      A tuple of (directory, basename, extension).
+    """
+
+    googlename = self.RepositoryName()
+    project, rest = os.path.split(googlename)
+    return (project,) + os.path.splitext(rest)
+
+  def BaseName(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 NoExtension(self):
+    """File has no source file extension."""
+    return '/'.join(self.Split()[0:2])
+
+  def IsSource(self):
+    """File has a source file extension."""
+    return self.Extension()[1:] in ('c', 'cc', 'cpp', 'cxx')
+
+
+def _ShouldPrintError(category, confidence, linenum):
+  """If confidence >= verbose, category passes filter and is not suppressed."""
+
+  # There are three ways we might decide not to print an error message:
+  # a "NOLINT(category)" comment appears in the source,
+  # the verbosity level isn't high enough, or the filters filter it out.
+  if IsErrorSuppressedByNolint(category, linenum):
+    return False
+
+  if confidence < _cpplint_state.verbose_level:
+    return False
+
+  is_filtered = False
+  for one_filter in _Filters():
+    if one_filter.startswith('-'):
+      if category.startswith(one_filter[1:]):
+        is_filtered = True
+    elif one_filter.startswith('+'):
+      if category.startswith(one_filter[1:]):
+        is_filtered = False
+    else:
+      assert False  # should have been checked for in SetFilter.
+  if is_filtered:
+    return False
+
+  return True
+
+
+def Error(filename, linenum, category, confidence, message):
+  """Logs the fact we've found a lint error.
+
+  We log where the error was found, and also our confidence in the error,
+  that is, how certain we are this is a legitimate style regression, and
+  not a misidentification or a use that's sometimes justified.
+
+  False positives can be suppressed by the use of
+  "cpplint(category)"  comments on the offending line.  These are
+  parsed into _error_suppressions.
+
+  Args:
+    filename: The name of the file containing the error.
+    linenum: The number of the line containing the error.
+    category: A string used to describe the "category" this bug
+      falls under: "whitespace", say, or "runtime".  Categories
+      may have a hierarchy separated by slashes: "whitespace/indent".
+    confidence: A number from 1-5 representing a confidence score for
+      the error, with 5 meaning that we are certain of the problem,
+      and 1 meaning that it could be a legitimate construct.
+    message: The error message.
+  """
+  if _ShouldPrintError(category, confidence, linenum):
+    _cpplint_state.IncrementErrorCount(category)
+    if _cpplint_state.output_format == 'vs7':
+      sys.stderr.write('%s(%s):  %s  [%s] [%d]\n' % (
+          filename, linenum, message, category, confidence))
+    elif _cpplint_state.output_format == 'eclipse':
+      sys.stderr.write('%s:%s: warning: %s  [%s] [%d]\n' % (
+          filename, linenum, message, category, confidence))
+    else:
+      sys.stderr.write('%s:%s:  %s  [%s] [%d]\n' % (
+          filename, linenum, message, category, confidence))
+
+
+# Matches standard C++ escape sequences per 2.13.2.3 of the C++ standard.
+_RE_PATTERN_CLEANSE_LINE_ESCAPES = re.compile(
+    r'\\([abfnrtv?"\\\']|\d+|x[0-9a-fA-F]+)')
+# Match a single C style comment on the same line.
+_RE_PATTERN_C_COMMENTS = r'/\*(?:[^*]|\*(?!/))*\*/'
+# Matches multi-line C style 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*' + _RE_PATTERN_C_COMMENTS + r'\s*$|' +
+    _RE_PATTERN_C_COMMENTS + r'\s+|' +
+    r'\s+' + _RE_PATTERN_C_COMMENTS + r'(?=\W)|' +
+    _RE_PATTERN_C_COMMENTS + r')')
+
+
+def IsCppString(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 CleanseRawStrings(raw_lines):
+  """Removes C++11 raw strings from lines.
+
+    Before:
+      static const char kData[] = R"(
+          multi-line string
+          )";
+
+    After:
+      static const char kData[] = ""
+          (replaced by blank line)
+          "";
+
+  Args:
+    raw_lines: list of raw lines.
+
+  Returns:
+    list of lines with C++11 raw strings replaced by empty strings.
+  """
+
+  delimiter = None
+  lines_without_raw_strings = []
+  for line in raw_lines:
+    if delimiter:
+      # Inside a raw string, look for the end
+      end = line.find(delimiter)
+      if end >= 0:
+        # Found the end of the string, match leading space for this
+        # line and resume copying the original lines, and also insert
+        # a "" on the last line.
+        leading_space = Match(r'^(\s*)\S', line)
+        line = leading_space.group(1) + '""' + line[end + len(delimiter):]
+        delimiter = None
+      else:
+        # Haven't found the end yet, append a blank line.
+        line = '""'
+
+    # Look for beginning of a raw string, and replace them with
+    # empty strings.  This is done in a loop to handle multiple raw
+    # strings on the same line.
+    while delimiter is None:
+      # Look for beginning of a raw string.
+      # See 2.14.15 [lex.string] for syntax.
+      matched = Match(r'^(.*)\b(?:R|u8R|uR|UR|LR)"([^\s\\()]*)\((.*)$', line)
+      if matched:
+        delimiter = ')' + matched.group(2) + '"'
+
+        end = matched.group(3).find(delimiter)
+        if end >= 0:
+          # Raw string ended on same line
+          line = (matched.group(1) + '""' +
+                  matched.group(3)[end + len(delimiter):])
+          delimiter = None
+        else:
+          # Start of a multi-line raw string
+          line = matched.group(1) + '""'
+      else:
+        break
+
+    lines_without_raw_strings.append(line)
+
+  # TODO(unknown): if delimiter is not None here, we might want to
+  # emit a warning for unterminated string.
+  return lines_without_raw_strings
+
+
+def FindNextMultiLineCommentStart(lines, lineix):
+  """Find the beginning marker for a multiline comment."""
+  while lineix < len(lines):
+    if lines[lineix].strip().startswith('/*'):
+      # Only return this marker if the comment goes beyond this line
+      if lines[lineix].strip().find('*/', 2) < 0:
+        return lineix
+    lineix += 1
+  return len(lines)
+
+
+def FindNextMultiLineCommentEnd(lines, lineix):
+  """We are inside a comment, find the end marker."""
+  while lineix < len(lines):
+    if lines[lineix].strip().endswith('*/'):
+      return lineix
+    lineix += 1
+  return len(lines)
+
+
+def RemoveMultiLineCommentsFromRange(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] = '/**/'
+
+
+def RemoveMultiLineComments(filename, lines, error):
+  """Removes multiline (c-style) comments from lines."""
+  lineix = 0
+  while lineix < len(lines):
+    lineix_begin = FindNextMultiLineCommentStart(lines, lineix)
+    if lineix_begin >= len(lines):
+      return
+    lineix_end = FindNextMultiLineCommentEnd(lines, lineix_begin)
+    if lineix_end >= len(lines):
+      error(filename, lineix_begin + 1, 'readability/multiline_comment', 5,
+            'Could not find end of multi-line comment')
+      return
+    RemoveMultiLineCommentsFromRange(lines, lineix_begin, lineix_end + 1)
+    lineix = lineix_end + 1
+
+
+def CleanseComments(line):
+  """Removes //-comments and single-line C-style /* */ comments.
+
+  Args:
+    line: A line of C++ source.
+
+  Returns:
+    The line with single-line comments removed.
+  """
+  commentpos = line.find('//')
+  if commentpos != -1 and not IsCppString(line[:commentpos]):
+    line = line[:commentpos].rstrip()
+  # get rid of /* ... */
+  return _RE_PATTERN_CLEANSE_LINE_C_COMMENTS.sub('', line)
+
+
+class CleansedLines(object):
+  """Holds 4 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.
+  3) raw_lines member contains all the lines without processing.
+  4) lines_without_raw_strings member is same as raw_lines, but with C++11 raw
+     strings removed.
+  All these 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)
+    self.lines_without_raw_strings = CleanseRawStrings(lines)
+    for linenum in range(len(self.lines_without_raw_strings)):
+      self.lines.append(CleanseComments(
+          self.lines_without_raw_strings[linenum]))
+      elided = self._CollapseStrings(self.lines_without_raw_strings[linenum])
+      self.elided.append(CleanseComments(elided))
+
+  def NumLines(self):
+    """Returns the number of lines represented."""
+    return self.num_lines
+
+  @staticmethod
+  def _CollapseStrings(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 _RE_PATTERN_INCLUDE.match(elided):
+      return 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)
+
+    # Replace quoted strings and digit separators.  Both single quotes
+    # and double quotes are processed in the same loop, otherwise
+    # nested quotes wouldn't work.
+    collapsed = ''
+    while True:
+      # Find the first quote character
+      match = Match(r'^([^\'"]*)([\'"])(.*)$', elided)
+      if not match:
+        collapsed += elided
+        break
+      head, quote, tail = match.groups()
+
+      if quote == '"':
+        # Collapse double quoted strings
+        second_quote = tail.find('"')
+        if second_quote >= 0:
+          collapsed += head + '""'
+          elided = tail[second_quote + 1:]
+        else:
+          # Unmatched double quote, don't bother processing the rest
+          # of the line since this is probably a multiline string.
+          collapsed += elided
+          break
+      else:
+        # Found single quote, check nearby text to eliminate digit separators.
+        #
+        # There is no special handling for floating point here, because
+        # the integer/fractional/exponent parts would all be parsed
+        # correctly as long as there are digits on both sides of the
+        # separator.  So we are fine as long as we don't see something
+        # like "0.'3" (gcc 4.9.0 will not allow this literal).
+        if Search(r'\b(?:0[bBxX]?|[1-9])[0-9a-fA-F]*$', head):
+          match_literal = Match(r'^((?:\'?[0-9a-zA-Z_])*)(.*)$', "'" + tail)
+          collapsed += head + match_literal.group(1).replace("'", '')
+          elided = match_literal.group(2)
+        else:
+          second_quote = tail.find('\'')
+          if second_quote >= 0:
+            collapsed += head + "''"
+            elided = tail[second_quote + 1:]
+          else:
+            # Unmatched single quote
+            collapsed += elided
+            break
+
+    return collapsed
+
+
+def FindEndOfExpressionInLine(line, startpos, stack):
+  """Find the position just after the end of current parenthesized expression.
+
+  Args:
+    line: a CleansedLines line.
+    startpos: start searching at this position.
+    stack: nesting stack at startpos.
+
+  Returns:
+    On finding matching end: (index just after matching end, None)
+    On finding an unclosed expression: (-1, None)
+    Otherwise: (-1, new stack at end of this line)
+  """
+  for i in xrange(startpos, len(line)):
+    char = line[i]
+    if char in '([{':
+      # Found start of parenthesized expression, push to expression stack
+      stack.append(char)
+    elif char == '<':
+      # Found potential start of template argument list
+      if i > 0 and line[i - 1] == '<':
+        # Left shift operator
+        if stack and stack[-1] == '<':
+          stack.pop()
+          if not stack:
+            return (-1, None)
+      elif i > 0 and Search(r'\boperator\s*$', line[0:i]):
+        # operator<, don't add to stack
+        continue
+      else:
+        # Tentative start of template argument list
+        stack.append('<')
+    elif char in ')]}':
+      # Found end of parenthesized expression.
+      #
+      # If we are currently expecting a matching '>', the pending '<'
+      # must have been an operator.  Remove them from expression stack.
+      while stack and stack[-1] == '<':
+        stack.pop()
+      if not stack:
+        return (-1, None)
+      if ((stack[-1] == '(' and char == ')') or
+          (stack[-1] == '[' and char == ']') or
+          (stack[-1] == '{' and char == '}')):
+        stack.pop()
+        if not stack:
+          return (i + 1, None)
+      else:
+        # Mismatched parentheses
+        return (-1, None)
+    elif char == '>':
+      # Found potential end of template argument list.
+
+      # Ignore "->" and operator functions
+      if (i > 0 and
+          (line[i - 1] == '-' or Search(r'\boperator\s*$', line[0:i - 1]))):
+        continue
+
+      # Pop the stack if there is a matching '<'.  Otherwise, ignore
+      # this '>' since it must be an operator.
+      if stack:
+        if stack[-1] == '<':
+          stack.pop()
+          if not stack:
+            return (i + 1, None)
+    elif char == ';':
+      # Found something that look like end of statements.  If we are currently
+      # expecting a '>', the matching '<' must have been an operator, since
+      # template argument list should not contain statements.
+      while stack and stack[-1] == '<':
+        stack.pop()
+      if not stack:
+        return (-1, None)
+
+  # Did not find end of expression or unbalanced parentheses on this line
+  return (-1, stack)
+
+
+def CloseExpression(clean_lines, linenum, pos):
+  """If input points to ( or { or [ or <, finds the position that closes it.
+
+  If lines[linenum][pos] points to a '(' or '{' or '[' or '<', finds the
+  linenum/pos that correspond to the closing of the expression.
+
+  TODO(unknown): cpplint spends a fair bit of time matching parentheses.
+  Ideally we would want to index all opening and closing parentheses once
+  and have CloseExpression be just a simple lookup, but due to preprocessor
+  tricks, this is not so easy.
+
+  Args:
+    clean_lines: A CleansedLines instance containing the file.
+    linenum: The number of the line to check.
+    pos: A position on the line.
+
+  Returns:
+    A tuple (line, linenum, pos) pointer *past* the closing brace, or
+    (line, len(lines), -1) if we never find a close.  Note we ignore
+    strings and comments when matching; and the line we return is the
+    'cleansed' line at linenum.
+  """
+
+  line = clean_lines.elided[linenum]
+  if (line[pos] not in '({[<') or Match(r'<[<=]', line[pos:]):
+    return (line, clean_lines.NumLines(), -1)
+
+  # Check first line
+  (end_pos, stack) = FindEndOfExpressionInLine(line, pos, [])
+  if end_pos > -1:
+    return (line, linenum, end_pos)
+
+  # Continue scanning forward
+  while stack and linenum < clean_lines.NumLines() - 1:
+    linenum += 1
+    line = clean_lines.elided[linenum]
+    (end_pos, stack) = FindEndOfExpressionInLine(line, 0, stack)
+    if end_pos > -1:
+      return (line, linenum, end_pos)
+
+  # Did not find end of expression before end of file, give up
+  return (line, clean_lines.NumLines(), -1)
+
+
+def FindStartOfExpressionInLine(line, endpos, stack):
+  """Find position at the matching start of current expression.
+
+  This is almost the reverse of FindEndOfExpressionInLine, but note
+  that the input position and returned position differs by 1.
+
+  Args:
+    line: a CleansedLines line.
+    endpos: start searching at this position.
+    stack: nesting stack at endpos.
+
+  Returns:
+    On finding matching start: (index at matching start, None)
+    On finding an unclosed expression: (-1, None)
+    Otherwise: (-1, new stack at beginning of this line)
+  """
+  i = endpos
+  while i >= 0:
+    char = line[i]
+    if char in ')]}':
+      # Found end of expression, push to expression stack
+      stack.append(char)
+    elif char == '>':
+      # Found potential end of template argument list.
+      #
+      # Ignore it if it's a "->" or ">=" or "operator>"
+      if (i > 0 and
+          (line[i - 1] == '-' or
+           Match(r'\s>=\s', line[i - 1:]) or
+           Search(r'\boperator\s*$', line[0:i]))):
+        i -= 1
+      else:
+        stack.append('>')
+    elif char == '<':
+      # Found potential start of template argument list
+      if i > 0 and line[i - 1] == '<':
+        # Left shift operator
+        i -= 1
+      else:
+        # If there is a matching '>', we can pop the expression stack.
+        # Otherwise, ignore this '<' since it must be an operator.
+        if stack and stack[-1] == '>':
+          stack.pop()
+          if not stack:
+            return (i, None)
+    elif char in '([{':
+      # Found start of expression.
+      #
+      # If there are any unmatched '>' on the stack, they must be
+      # operators.  Remove those.
+      while stack and stack[-1] == '>':
+        stack.pop()
+      if not stack:
+        return (-1, None)
+      if ((char == '(' and stack[-1] == ')') or
+          (char == '[' and stack[-1] == ']') or
+          (char == '{' and stack[-1] == '}')):
+        stack.pop()
+        if not stack:
+          return (i, None)
+      else:
+        # Mismatched parentheses
+        return (-1, None)
+    elif char == ';':
+      # Found something that look like end of statements.  If we are currently
+      # expecting a '<', the matching '>' must have been an operator, since
+      # template argument list should not contain statements.
+      while stack and stack[-1] == '>':
+        stack.pop()
+      if not stack:
+        return (-1, None)
+
+    i -= 1
+
+  return (-1, stack)
+
+
+def ReverseCloseExpression(clean_lines, linenum, pos):
+  """If input points to ) or } or ] or >, finds the position that opens it.
+
+  If lines[linenum][pos] points to a ')' or '}' or ']' or '>', finds the
+  linenum/pos that correspond to the opening of the expression.
+
+  Args:
+    clean_lines: A CleansedLines instance containing the file.
+    linenum: The number of the line to check.
+    pos: A position on the line.
+
+  Returns:
+    A tuple (line, linenum, pos) pointer *at* the opening brace, or
+    (line, 0, -1) if we never find the matching opening brace.  Note
+    we ignore strings and comments when matching; and the line we
+    return is the 'cleansed' line at linenum.
+  """
+  line = clean_lines.elided[linenum]
+  if line[pos] not in ')}]>':
+    return (line, 0, -1)
+
+  # Check last line
+  (start_pos, stack) = FindStartOfExpressionInLine(line, pos, [])
+  if start_pos > -1:
+    return (line, linenum, start_pos)
+
+  # Continue scanning backward
+  while stack and linenum > 0:
+    linenum -= 1
+    line = clean_lines.elided[linenum]
+    (start_pos, stack) = FindStartOfExpressionInLine(line, len(line) - 1, stack)
+    if start_pos > -1:
+      return (line, linenum, start_pos)
+
+  # Did not find start of expression before beginning of file, give up
+  return (line, 0, -1)
+
+
+def CheckForCopyright(filename, 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(filename, 0, 'legal/copyright', 5,
+          'No copyright message found.  '
+          'You should have a line: "Copyright [year] <Copyright Owner>"')
+
+
+def GetIndentLevel(line):
+  """Return the number of leading spaces in line.
+
+  Args:
+    line: A string to check.
+
+  Returns:
+    An integer count of leading spaces, possibly zero.
+  """
+  indent = Match(r'^( *)\S', line)
+  if indent:
+    return len(indent.group(1))
+  else:
+    return 0
+
+
+def GetHeaderGuardCPPVariable(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 cpplint is invoked from Emacs's
+  # flymake.
+  filename = re.sub(r'_flymake\.h$', '.h', filename)
+  filename = re.sub(r'/\.flymake/([^/]*)$', r'/\1', filename)
+  # Replace 'c++' with 'cpp'.
+  filename = filename.replace('C++', 'cpp').replace('c++', 'cpp')
+  
+  fileinfo = FileInfo(filename)
+  file_path_from_root = fileinfo.RepositoryName()
+  if _root:
+    file_path_from_root = re.sub('^' + _root + os.sep, '', file_path_from_root)
+  return re.sub(r'[^a-zA-Z0-9]', '_', file_path_from_root).upper() + '_'
+
+
+def CheckForHeaderGuard(filename, clean_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.
+    clean_lines: A CleansedLines instance containing the file.
+    error: The function to call with any errors found.
+  """
+
+  # Don't check for header guards if there are error suppression
+  # comments somewhere in this file.
+  #
+  # Because this is silencing a warning for a nonexistent line, we
+  # only support the very specific NOLINT(build/header_guard) syntax,
+  # and not the general NOLINT or NOLINT(*) syntax.
+  raw_lines = clean_lines.lines_without_raw_strings
+  for i in raw_lines:
+    if Search(r'//\s*NOLINT\(build/header_guard\)', i):
+      return
+
+  cppvar = GetHeaderGuardCPPVariable(filename)
+
+  ifndef = ''
+  ifndef_linenum = 0
+  define = ''
+  endif = ''
+  endif_linenum = 0
+  for linenum, line in enumerate(raw_lines):
+    linesplit = line.split()
+    if len(linesplit) >= 2:
+      # find the first occurrence of #ifndef and #define, save arg
+      if not ifndef and linesplit[0] == '#ifndef':
+        # set ifndef to the header guard presented on the #ifndef line.
+        ifndef = linesplit[1]
+        ifndef_linenum = linenum
+      if not define and linesplit[0] == '#define':
+        define = linesplit[1]
+    # find the last occurrence of #endif, save entire line
+    if line.startswith('#endif'):
+      endif = line
+      endif_linenum = linenum
+
+  if not ifndef or not define or ifndef != define:
+    error(filename, 0, 'build/header_guard', 5,
+          'No #ifndef header guard found, suggested CPP variable is: %s' %
+          cppvar)
+    return
+
+  # The guard should be PATH_FILE_H_, but we also allow PATH_FILE_H__
+  # for backward compatibility.
+  if ifndef != cppvar:
+    error_level = 0
+    if ifndef != cppvar + '_':
+      error_level = 5
+
+    ParseNolintSuppressions(filename, raw_lines[ifndef_linenum], ifndef_linenum,
+                            error)
+    error(filename, ifndef_linenum, 'build/header_guard', error_level,
+          '#ifndef header guard has wrong style, please use: %s' % cppvar)
+
+  # Check for "//" comments on endif line.
+  ParseNolintSuppressions(filename, raw_lines[endif_linenum], endif_linenum,
+                          error)
+  match = Match(r'#endif\s*//\s*' + cppvar + r'(_)?\b', endif)
+  if match:
+    if match.group(1) == '_':
+      # Issue low severity warning for deprecated double trailing underscore
+      error(filename, endif_linenum, 'build/header_guard', 0,
+            '#endif line should be "#endif  // %s"' % cppvar)
+    return
+
+  # Didn't find the corresponding "//" comment.  If this file does not
+  # contain any "//" comments at all, it could be that the compiler
+  # only wants "/**/" comments, look for those instead.
+  no_single_line_comments = True
+  for i in xrange(1, len(raw_lines) - 1):
+    line = raw_lines[i]
+    if Match(r'^(?:(?:\'(?:\.|[^\'])*\')|(?:"(?:\.|[^"])*")|[^\'"])*//', line):
+      no_single_line_comments = False
+      break
+
+  if no_single_line_comments:
+    match = Match(r'#endif\s*/\*\s*' + cppvar + r'(_)?\s*\*/', endif)
+    if match:
+      if match.group(1) == '_':
+        # Low severity warning for double trailing underscore
+        error(filename, endif_linenum, 'build/header_guard', 0,
+              '#endif line should be "#endif  /* %s */"' % cppvar)
+      return
+
+  # Didn't find anything
+  error(filename, endif_linenum, 'build/header_guard', 5,
+        '#endif line should be "#endif  // %s"' % cppvar)
+
+
+def CheckHeaderFileIncluded(filename, include_state, error):
+  """Logs an error if a .cc file does not include its header."""
+
+  # Do not check test files
+  if filename.endswith('_test.cc') or filename.endswith('_unittest.cc'):
+    return
+
+  fileinfo = FileInfo(filename)
+  headerfile = filename[0:len(filename) - 2] + 'h'
+  if not os.path.exists(headerfile):
+    return
+  headername = FileInfo(headerfile).RepositoryName()
+  first_include = 0
+  for section_list in include_state.include_list:
+    for f in section_list:
+      if headername in f[0] or f[0] in headername:
+        return
+      if not first_include:
+        first_include = f[1]
+
+  error(filename, first_include, 'build/include', 5,
+        '%s should include its header file %s' % (fileinfo.RepositoryName(),
+                                                  headername))
+
+
+def CheckForBadCharacters(filename, lines, error):
+  """Logs an error for each line containing bad characters.
+
+  Two kinds of bad characters:
+
+  1. 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.
+
+  2. NUL bytes.  These are problematic for some tools.
+
+  Args:
+    filename: The name of the current file.
+    lines: An array of strings, each representing a line of the file.
+    error: The function to call with any errors found.
+  """
+  for linenum, line in enumerate(lines):
+    if u'\ufffd' in line:
+      error(filename, linenum, 'readability/utf8', 5,
+            'Line contains invalid UTF-8 (or Unicode replacement character).')
+    if '\0' in line:
+      error(filename, linenum, 'readability/nul', 5, 'Line contains NUL byte.')
+
+
+def CheckForNewlineAtEOF(filename, lines, error):
+  """Logs an error if there is no newline char at the end of the file.
+
+  Args:
+    filename: The name of the current file.
+    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(filename, len(lines) - 2, 'whitespace/ending_newline', 5,
+          'Could not find a newline character at the end of the file.')
+
+
+def CheckForMultilineCommentsAndStrings(filename, clean_lines, linenum, 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:
+    filename: The name of the current file.
+    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.
+  """
+  line = clean_lines.elided[linenum]
+
+  # 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(filename, linenum, '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(filename, linenum, 'readability/multiline_string', 5,
+          'Multi-line string ("...") found.  This lint script doesn\'t '
+          'do well with such strings, and may give bogus warnings.  '
+          'Use C++11 raw strings or concatenation instead.')
+
+
+# (non-threadsafe name, thread-safe alternative, validation pattern)
+#
+# The validation pattern is used to eliminate false positives such as:
+#  _rand();               // false positive due to substring match.
+#  ->rand();              // some member function rand().
+#  ACMRandom rand(seed);  // some variable named rand.
+#  ISAACRandom rand();    // another variable named rand.
+#
+# Basically we require the return value of these functions to be used
+# in some expression context on the same line by matching on some
+# operator before the function name.  This eliminates constructors and
+# member function calls.
+_UNSAFE_FUNC_PREFIX = r'(?:[-+*/=%^&|(<]\s*|>\s+)'
+_THREADING_LIST = (
+    ('asctime(', 'asctime_r(', _UNSAFE_FUNC_PREFIX + r'asctime\([^)]+\)'),
+    ('ctime(', 'ctime_r(', _UNSAFE_FUNC_PREFIX + r'ctime\([^)]+\)'),
+    ('getgrgid(', 'getgrgid_r(', _UNSAFE_FUNC_PREFIX + r'getgrgid\([^)]+\)'),
+    ('getgrnam(', 'getgrnam_r(', _UNSAFE_FUNC_PREFIX + r'getgrnam\([^)]+\)'),
+    ('getlogin(', 'getlogin_r(', _UNSAFE_FUNC_PREFIX + r'getlogin\(\)'),
+    ('getpwnam(', 'getpwnam_r(', _UNSAFE_FUNC_PREFIX + r'getpwnam\([^)]+\)'),
+    ('getpwuid(', 'getpwuid_r(', _UNSAFE_FUNC_PREFIX + r'getpwuid\([^)]+\)'),
+    ('gmtime(', 'gmtime_r(', _UNSAFE_FUNC_PREFIX + r'gmtime\([^)]+\)'),
+    ('localtime(', 'localtime_r(', _UNSAFE_FUNC_PREFIX + r'localtime\([^)]+\)'),
+    ('rand(', 'rand_r(', _UNSAFE_FUNC_PREFIX + r'rand\(\)'),
+    ('strtok(', 'strtok_r(',
+     _UNSAFE_FUNC_PREFIX + r'strtok\([^)]+\)'),
+    ('ttyname(', 'ttyname_r(', _UNSAFE_FUNC_PREFIX + r'ttyname\([^)]+\)'),
+    )
+
+
+def CheckPosixThreading(filename, clean_lines, linenum, 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:
+    filename: The name of the current file.
+    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.
+  """
+  line = clean_lines.elided[linenum]
+  for single_thread_func, multithread_safe_func, pattern in _THREADING_LIST:
+    # Additional pattern matching check to confirm that this is the
+    # function we are looking for
+    if Search(pattern, line):
+      error(filename, linenum, 'runtime/threadsafe_fn', 2,
+            'Consider using ' + multithread_safe_func +
+            '...) instead of ' + single_thread_func +
+            '...) for improved thread safety.')
+
+
+def CheckVlogArguments(filename, clean_lines, linenum, error):
+  """Checks that VLOG() is only used for defining a logging level.
+
+  For example, VLOG(2) is correct. VLOG(INFO), VLOG(WARNING), VLOG(ERROR), and
+  VLOG(FATAL) are not.
+
+  Args:
+    filename: The name of the current file.
+    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.
+  """
+  line = clean_lines.elided[linenum]
+  if Search(r'\bVLOG\((INFO|ERROR|WARNING|DFATAL|FATAL)\)', line):
+    error(filename, linenum, 'runtime/vlog', 5,
+          'VLOG() should be used with numeric verbosity level.  '
+          'Use LOG() if you want symbolic severity levels.')
+
+# Matches invalid increment: *count++, which moves pointer instead of
+# incrementing a value.
+_RE_PATTERN_INVALID_INCREMENT = re.compile(
+    r'^\s*\*\w+(\+\+|--);')
+
+
+def CheckInvalidIncrement(filename, clean_lines, linenum, 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:
+    filename: The name of the current file.
+    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.
+  """
+  line = clean_lines.elided[linenum]
+  if _RE_PATTERN_INVALID_INCREMENT.match(line):
+    error(filename, linenum, 'runtime/invalid_increment', 5,
+          'Changing pointer instead of value (or unused value of operator*).')
+
+
+def IsMacroDefinition(clean_lines, linenum):
+  if Search(r'^#define', clean_lines[linenum]):
+    return True
+
+  if linenum > 0 and Search(r'\\$', clean_lines[linenum - 1]):
+    return True
+
+  return False
+
+
+def IsForwardClassDeclaration(clean_lines, linenum):
+  return Match(r'^\s*(\btemplate\b)*.*class\s+\w+;\s*$', clean_lines[linenum])
+
+
+class _BlockInfo(object):
+  """Stores information about a generic block of code."""
+
+  def __init__(self, seen_open_brace):
+    self.seen_open_brace = seen_open_brace
+    self.open_parentheses = 0
+    self.inline_asm = _NO_ASM
+    self.check_namespace_indentation = False
+
+  def CheckBegin(self, filename, clean_lines, linenum, error):
+    """Run checks that applies to text up to the opening brace.
+
+    This is mostly for checking the text after the class identifier
+    and the "{", usually where the base class is specified.  For other
+    blocks, there isn't much to check, so we always pass.
+
+    Args:
+      filename: The name of the current file.
+      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.
+    """
+    pass
+
+  def CheckEnd(self, filename, clean_lines, linenum, error):
+    """Run checks that applies to text after the closing brace.
+
+    This is mostly used for checking end of namespace comments.
+
+    Args:
+      filename: The name of the current file.
+      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.
+    """
+    pass
+
+  def IsBlockInfo(self):
+    """Returns true if this block is a _BlockInfo.
+
+    This is convenient for verifying that an object is an instance of
+    a _BlockInfo, but not an instance of any of the derived classes.
+
+    Returns:
+      True for this class, False for derived classes.
+    """
+    return self.__class__ == _BlockInfo
+
+
+class _ExternCInfo(_BlockInfo):
+  """Stores information about an 'extern "C"' block."""
+
+  def __init__(self):
+    _BlockInfo.__init__(self, True)
+
+
+class _ClassInfo(_BlockInfo):
+  """Stores information about a class."""
+
+  def __init__(self, name, class_or_struct, clean_lines, linenum):
+    _BlockInfo.__init__(self, False)
+    self.name = name
+    self.starting_linenum = linenum
+    self.is_derived = False
+    self.check_namespace_indentation = True
+    if class_or_struct == 'struct':
+      self.access = 'public'
+      self.is_struct = True
+    else:
+      self.access = 'private'
+      self.is_struct = False
+
+    # Remember initial indentation level for this class.  Using raw_lines here
+    # instead of elided to account for leading comments.
+    self.class_indent = GetIndentLevel(clean_lines.raw_lines[linenum])
+
+    # Try to find the end of the class.  This will be confused by things like:
+    #   class A {
+    #   } *x = { ...
+    #
+    # But it's still good enough for CheckSectionSpacing.
+    self.last_line = 0
+    depth = 0
+    for i in range(linenum, clean_lines.NumLines()):
+      line = clean_lines.elided[i]
+      depth += line.count('{') - line.count('}')
+      if not depth:
+        self.last_line = i
+        break
+
+  def CheckBegin(self, filename, clean_lines, linenum, error):
+    # Look for a bare ':'
+    if Search('(^|[^:]):($|[^:])', clean_lines.elided[linenum]):
+      self.is_derived = True
+
+  def CheckEnd(self, filename, clean_lines, linenum, error):
+    # If there is a DISALLOW macro, it should appear near the end of
+    # the class.
+    seen_last_thing_in_class = False
+    for i in xrange(linenum - 1, self.starting_linenum, -1):
+      match = Search(
+          r'\b(DISALLOW_COPY_AND_ASSIGN|DISALLOW_IMPLICIT_CONSTRUCTORS)\(' +
+          self.name + r'\)',
+          clean_lines.elided[i])
+      if match:
+        if seen_last_thing_in_class:
+          error(filename, i, 'readability/constructors', 3,
+                match.group(1) + ' should be the last thing in the class')
+        break
+
+      if not Match(r'^\s*$', clean_lines.elided[i]):
+        seen_last_thing_in_class = True
+
+    # Check that closing brace is aligned with beginning of the class.
+    # Only do this if the closing brace is indented by only whitespaces.
+    # This means we will not check single-line class definitions.
+    indent = Match(r'^( *)\}', clean_lines.elided[linenum])
+    if indent and len(indent.group(1)) != self.class_indent:
+      if self.is_struct:
+        parent = 'struct ' + self.name
+      else:
+        parent = 'class ' + self.name
+      error(filename, linenum, 'whitespace/indent', 3,
+            'Closing brace should be aligned with beginning of %s' % parent)
+
+
+class _NamespaceInfo(_BlockInfo):
+  """Stores information about a namespace."""
+
+  def __init__(self, name, linenum):
+    _BlockInfo.__init__(self, False)
+    self.name = name or ''
+    self.starting_linenum = linenum
+    self.check_namespace_indentation = True
+
+  def CheckEnd(self, filename, clean_lines, linenum, error):
+    """Check end of namespace comments."""
+    line = clean_lines.raw_lines[linenum]
+
+    # Check how many lines is enclosed in this namespace.  Don't issue
+    # warning for missing namespace comments if there aren't enough
+    # lines.  However, do apply checks if there is already an end of
+    # namespace comment and it's incorrect.
+    #
+    # TODO(unknown): We always want to check end of namespace comments
+    # if a namespace is large, but sometimes we also want to apply the
+    # check if a short namespace contained nontrivial things (something
+    # other than forward declarations).  There is currently no logic on
+    # deciding what these nontrivial things are, so this check is
+    # triggered by namespace size only, which works most of the time.
+    if (linenum - self.starting_linenum < 10
+        and not Match(r'};*\s*(//|/\*).*\bnamespace\b', line)):
+      return
+
+    # Look for matching comment at end of namespace.
+    #
+    # Note that we accept C style "/* */" comments for terminating
+    # namespaces, so that code that terminate namespaces inside
+    # preprocessor macros can be cpplint clean.
+    #
+    # We also accept stuff like "// end of namespace <name>." with the
+    # period at the end.
+    #
+    # Besides these, we don't accept anything else, otherwise we might
+    # get false negatives when existing comment is a substring of the
+    # expected namespace.
+    if self.name:
+      # Named namespace
+      if not Match((r'};*\s*(//|/\*).*\bnamespace\s+' + re.escape(self.name) +
+                    r'[\*/\.\\\s]*$'),
+                   line):
+        error(filename, linenum, 'readability/namespace', 5,
+              'Namespace should be terminated with "// namespace %s"' %
+              self.name)
+    else:
+      # Anonymous namespace
+      if not Match(r'};*\s*(//|/\*).*\bnamespace[\*/\.\\\s]*$', line):
+        # If "// namespace anonymous" or "// anonymous namespace (more text)",
+        # mention "// anonymous namespace" as an acceptable form
+        if Match(r'}.*\b(namespace anonymous|anonymous namespace)\b', line):
+          error(filename, linenum, 'readability/namespace', 5,
+                'Anonymous namespace should be terminated with "// namespace"'
+                ' or "// anonymous namespace"')
+        else:
+          error(filename, linenum, 'readability/namespace', 5,
+                'Anonymous namespace should be terminated with "// namespace"')
+
+
+class _PreprocessorInfo(object):
+  """Stores checkpoints of nesting stacks when #if/#else is seen."""
+
+  def __init__(self, stack_before_if):
+    # The entire nesting stack before #if
+    self.stack_before_if = stack_before_if
+
+    # The entire nesting stack up to #else
+    self.stack_before_else = []
+
+    # Whether we have already seen #else or #elif
+    self.seen_else = False
+
+
+class NestingState(object):
+  """Holds states related to parsing braces."""
+
+  def __init__(self):
+    # Stack for tracking all braces.  An object is pushed whenever we
+    # see a "{", and popped when we see a "}".  Only 3 types of
+    # objects are possible:
+    # - _ClassInfo: a class or struct.
+    # - _NamespaceInfo: a namespace.
+    # - _BlockInfo: some other type of block.
+    self.stack = []
+
+    # Top of the previous stack before each Update().
+    #
+    # Because the nesting_stack is updated at the end of each line, we
+    # had to do some convoluted checks to find out what is the current
+    # scope at the beginning of the line.  This check is simplified by
+    # saving the previous top of nesting stack.
+    #
+    # We could save the full stack, but we only need the top.  Copying
+    # the full nesting stack would slow down cpplint by ~10%.
+    self.previous_stack_top = []
+
+    # Stack of _PreprocessorInfo objects.
+    self.pp_stack = []
+
+  def SeenOpenBrace(self):
+    """Check if we have seen the opening brace for the innermost block.
+
+    Returns:
+      True if we have seen the opening brace, False if the innermost
+      block is still expecting an opening brace.
+    """
+    return (not self.stack) or self.stack[-1].seen_open_brace
+
+  def InNamespaceBody(self):
+    """Check if we are currently one level inside a namespace body.
+
+    Returns:
+      True if top of the stack is a namespace block, False otherwise.
+    """
+    return self.stack and isinstance(self.stack[-1], _NamespaceInfo)
+
+  def InExternC(self):
+    """Check if we are currently one level inside an 'extern "C"' block.
+
+    Returns:
+      True if top of the stack is an extern block, False otherwise.
+    """
+    return self.stack and isinstance(self.stack[-1], _ExternCInfo)
+
+  def InClassDeclaration(self):
+    """Check if we are currently one level inside a class or struct declaration.
+
+    Returns:
+      True if top of the stack is a class/struct, False otherwise.
+    """
+    return self.stack and isinstance(self.stack[-1], _ClassInfo)
+
+  def InAsmBlock(self):
+    """Check if we are currently one level inside an inline ASM block.
+
+    Returns:
+      True if the top of the stack is a block containing inline ASM.
+    """
+    return self.stack and self.stack[-1].inline_asm != _NO_ASM
+
+  def InTemplateArgumentList(self, clean_lines, linenum, pos):
+    """Check if current position is inside template argument list.
+
+    Args:
+      clean_lines: A CleansedLines instance containing the file.
+      linenum: The number of the line to check.
+      pos: position just after the suspected template argument.
+    Returns:
+      True if (linenum, pos) is inside template arguments.
+    """
+    while linenum < clean_lines.NumLines():
+      # Find the earliest character that might indicate a template argument
+      line = clean_lines.elided[linenum]
+      match = Match(r'^[^{};=\[\]\.<>]*(.)', line[pos:])
+      if not match:
+        linenum += 1
+        pos = 0
+        continue
+      token = match.group(1)
+      pos += len(match.group(0))
+
+      # These things do not look like template argument list:
+      #   class Suspect {
+      #   class Suspect x; }
+      if token in ('{', '}', ';'): return False
+
+      # These things look like template argument list:
+      #   template <class Suspect>
+      #   template <class Suspect = default_value>
+      #   template <class Suspect[]>
+      #   template <class Suspect...>
+      if token in ('>', '=', '[', ']', '.'): return True
+
+      # Check if token is an unmatched '<'.
+      # If not, move on to the next character.
+      if token != '<':
+        pos += 1
+        if pos >= len(line):
+          linenum += 1
+          pos = 0
+        continue
+
+      # We can't be sure if we just find a single '<', and need to
+      # find the matching '>'.
+      (_, end_line, end_pos) = CloseExpression(clean_lines, linenum, pos - 1)
+      if end_pos < 0:
+        # Not sure if template argument list or syntax error in file
+        return False
+      linenum = end_line
+      pos = end_pos
+    return False
+
+  def UpdatePreprocessor(self, line):
+    """Update preprocessor stack.
+
+    We need to handle preprocessors due to classes like this:
+      #ifdef SWIG
+      struct ResultDetailsPageElementExtensionPoint {
+      #else
+      struct ResultDetailsPageElementExtensionPoint : public Extension {
+      #endif
+
+    We make the following assumptions (good enough for most files):
+    - Preprocessor condition evaluates to true from #if up to first
+      #else/#elif/#endif.
+
+    - Preprocessor condition evaluates to false from #else/#elif up
+      to #endif.  We still perform lint checks on these lines, but
+      these do not affect nesting stack.
+
+    Args:
+      line: current line to check.
+    """
+    if Match(r'^\s*#\s*(if|ifdef|ifndef)\b', line):
+      # Beginning of #if block, save the nesting stack here.  The saved
+      # stack will allow us to restore the parsing state in the #else case.
+      self.pp_stack.append(_PreprocessorInfo(copy.deepcopy(self.stack)))
+    elif Match(r'^\s*#\s*(else|elif)\b', line):
+      # Beginning of #else block
+      if self.pp_stack:
+        if not self.pp_stack[-1].seen_else:
+          # This is the first #else or #elif block.  Remember the
+          # whole nesting stack up to this point.  This is what we
+          # keep after the #endif.
+          self.pp_stack[-1].seen_else = True
+          self.pp_stack[-1].stack_before_else = copy.deepcopy(self.stack)
+
+        # Restore the stack to how it was before the #if
+        self.stack = copy.deepcopy(self.pp_stack[-1].stack_before_if)
+      else:
+        # TODO(unknown): unexpected #else, issue warning?
+        pass
+    elif Match(r'^\s*#\s*endif\b', line):
+      # End of #if or #else blocks.
+      if self.pp_stack:
+        # If we saw an #else, we will need to restore the nesting
+        # stack to its former state before the #else, otherwise we
+        # will just continue from where we left off.
+        if self.pp_stack[-1].seen_else:
+          # Here we can just use a shallow copy since we are the last
+          # reference to it.
+          self.stack = self.pp_stack[-1].stack_before_else
+        # Drop the corresponding #if
+        self.pp_stack.pop()
+      else:
+        # TODO(unknown): unexpected #endif, issue warning?
+        pass
+
+  # TODO(unknown): Update() is too long, but we will refactor later.
+  def Update(self, filename, clean_lines, linenum, error):
+    """Update nesting state with current line.
+
+    Args:
+      filename: The name of the current file.
+      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.
+    """
+    line = clean_lines.elided[linenum]
+
+    # Remember top of the previous nesting stack.
+    #
+    # The stack is always pushed/popped and not modified in place, so
+    # we can just do a shallow copy instead of copy.deepcopy.  Using
+    # deepcopy would slow down cpplint by ~28%.
+    if self.stack:
+      self.previous_stack_top = self.stack[-1]
+    else:
+      self.previous_stack_top = None
+
+    # Update pp_stack
+    self.UpdatePreprocessor(line)
+
+    # Count parentheses.  This is to avoid adding struct arguments to
+    # the nesting stack.
+    if self.stack:
+      inner_block = self.stack[-1]
+      depth_change = line.count('(') - line.count(')')
+      inner_block.open_parentheses += depth_change
+
+      # Also check if we are starting or ending an inline assembly block.
+      if inner_block.inline_asm in (_NO_ASM, _END_ASM):
+        if (depth_change != 0 and
+            inner_block.open_parentheses == 1 and
+            _MATCH_ASM.match(line)):
+          # Enter assembly block
+          inner_block.inline_asm = _INSIDE_ASM
+        else:
+          # Not entering assembly block.  If previous line was _END_ASM,
+          # we will now shift to _NO_ASM state.
+          inner_block.inline_asm = _NO_ASM
+      elif (inner_block.inline_asm == _INSIDE_ASM and
+            inner_block.open_parentheses == 0):
+        # Exit assembly block
+        inner_block.inline_asm = _END_ASM
+
+    # Consume namespace declaration at the beginning of the line.  Do
+    # this in a loop so that we catch same line declarations like this:
+    #   namespace proto2 { namespace bridge { class MessageSet; } }
+    while True:
+      # Match start of namespace.  The "\b\s*" below catches namespace
+      # declarations even if it weren't followed by a whitespace, this
+      # is so that we don't confuse our namespace checker.  The
+      # missing spaces will be flagged by CheckSpacing.
+      namespace_decl_match = Match(r'^\s*namespace\b\s*([:\w]+)?(.*)$', line)
+      if not namespace_decl_match:
+        break
+
+      new_namespace = _NamespaceInfo(namespace_decl_match.group(1), linenum)
+      self.stack.append(new_namespace)
+
+      line = namespace_decl_match.group(2)
+      if line.find('{') != -1:
+        new_namespace.seen_open_brace = True
+        line = line[line.find('{') + 1:]
+
+    # Look for a class declaration in whatever is left of the line
+    # after parsing namespaces.  The regexp accounts for decorated classes
+    # such as in:
+    #   class LOCKABLE API Object {
+    #   };
+    class_decl_match = Match(
+        r'^(\s*(?:template\s*<[\w\s<>,:]*>\s*)?'
+        r'(class|struct)\s+(?:[A-Z_]+\s+)*(\w+(?:::\w+)*))'
+        r'(.*)$', line)
+    if (class_decl_match and
+        (not self.stack or self.stack[-1].open_parentheses == 0)):
+      # We do not want to accept classes that are actually template arguments:
+      #   template <class Ignore1,
+      #             class Ignore2 = Default<Args>,
+      #             template <Args> class Ignore3>
+      #   void Function() {};
+      #
+      # To avoid template argument cases, we scan forward and look for
+      # an unmatched '>'.  If we see one, assume we are inside a
+      # template argument list.
+      end_declaration = len(class_decl_match.group(1))
+      if not self.InTemplateArgumentList(clean_lines, linenum, end_declaration):
+        self.stack.append(_ClassInfo(
+            class_decl_match.group(3), class_decl_match.group(2),
+            clean_lines, linenum))
+        line = class_decl_match.group(4)
+
+    # If we have not yet seen the opening brace for the innermost block,
+    # run checks here.
+    if not self.SeenOpenBrace():
+      self.stack[-1].CheckBegin(filename, clean_lines, linenum, error)
+
+    # Update access control if we are inside a class/struct
+    if self.stack and isinstance(self.stack[-1], _ClassInfo):
+      classinfo = self.stack[-1]
+      access_match = Match(
+          r'^(.*)\b(public|private|protected|signals)(\s+(?:slots\s*)?)?'
+          r':(?:[^:]|$)',
+          line)
+      if access_match:
+        classinfo.access = access_match.group(2)
+
+        # Check that access keywords are indented +1 space.  Skip this
+        # check if the keywords are not preceded by whitespaces.
+        indent = access_match.group(1)
+        if (len(indent) != classinfo.class_indent + 1 and
+            Match(r'^\s*$', indent)):
+          if classinfo.is_struct:
+            parent = 'struct ' + classinfo.name
+          else:
+            parent = 'class ' + classinfo.name
+          slots = ''
+          if access_match.group(3):
+            slots = access_match.group(3)
+          error(filename, linenum, 'whitespace/indent', 3,
+                '%s%s: should be indented +1 space inside %s' % (
+                    access_match.group(2), slots, parent))
+
+    # Consume braces or semicolons from what's left of the line
+    while True:
+      # Match first brace, semicolon, or closed parenthesis.
+      matched = Match(r'^[^{;)}]*([{;)}])(.*)$', line)
+      if not matched:
+        break
+
+      token = matched.group(1)
+      if token == '{':
+        # If namespace or class hasn't seen a opening brace yet, mark
+        # namespace/class head as complete.  Push a new block onto the
+        # stack otherwise.
+        if not self.SeenOpenBrace():
+          self.stack[-1].seen_open_brace = True
+        elif Match(r'^extern\s*"[^"]*"\s*\{', line):
+          self.stack.append(_ExternCInfo())
+        else:
+          self.stack.append(_BlockInfo(True))
+          if _MATCH_ASM.match(line):
+            self.stack[-1].inline_asm = _BLOCK_ASM
+
+      elif token == ';' or token == ')':
+        # If we haven't seen an opening brace yet, but we already saw
+        # a semicolon, this is probably a forward declaration.  Pop
+        # the stack for these.
+        #
+        # Similarly, if we haven't seen an opening brace yet, but we
+        # already saw a closing parenthesis, then these are probably
+        # function arguments with extra "class" or "struct" keywords.
+        # Also pop these stack for these.
+        if not self.SeenOpenBrace():
+          self.stack.pop()
+      else:  # token == '}'
+        # Perform end of block checks and pop the stack.
+        if self.stack:
+          self.stack[-1].CheckEnd(filename, clean_lines, linenum, error)
+          self.stack.pop()
+      line = matched.group(2)
+
+  def InnermostClass(self):
+    """Get class info on the top of the stack.
+
+    Returns:
+      A _ClassInfo object if we are inside a class, or None otherwise.
+    """
+    for i in range(len(self.stack), 0, -1):
+      classinfo = self.stack[i - 1]
+      if isinstance(classinfo, _ClassInfo):
+        return classinfo
+    return None
+
+  def CheckCompletedBlocks(self, filename, error):
+    """Checks that all classes and namespaces have been completely parsed.
+
+    Call this when all lines in a file have been processed.
+    Args:
+      filename: The name of the current file.
+      error: The function to call with any errors found.
+    """
+    # Note: This test can result in false positives if #ifdef constructs
+    # get in the way of brace matching. See the testBuildClass test in
+    # cpplint_unittest.py for an example of this.
+    for obj in self.stack:
+      if isinstance(obj, _ClassInfo):
+        error(filename, obj.starting_linenum, 'build/class', 5,
+              'Failed to find complete declaration of class %s' %
+              obj.name)
+      elif isinstance(obj, _NamespaceInfo):
+        error(filename, obj.starting_linenum, 'build/namespaces', 5,
+              'Failed to find complete declaration of namespace %s' %
+              obj.name)
+
+
+def CheckForNonStandardConstructs(filename, clean_lines, linenum,
+                                  nesting_state, error):
+  r"""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.
+
+  Additionally, check for constructor/destructor style violations and reference
+  members, as it is very convenient to do so while checking for
+  gcc-2 compliance.
+
+  Args:
+    filename: The name of the current file.
+    clean_lines: A CleansedLines instance containing the file.
+    linenum: The number of the line to check.
+    nesting_state: A NestingState instance which maintains information about
+                   the current stack of nested blocks being parsed.
+    error: A callable to which errors are reported, which takes 4 arguments:
+           filename, line number, error level, and message
+  """
+
+  # Remove comments from the line, but leave in strings for now.
+  line = clean_lines.lines[linenum]
+
+  if Search(r'printf\s*\(.*".*%[-+ ]?\d*q', line):
+    error(filename, linenum, 'runtime/printf_format', 3,
+          '%q in format strings is deprecated.  Use %ll instead.')
+
+  if Search(r'printf\s*\(.*".*%\d+\$', line):
+    error(filename, linenum, '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(filename, linenum, '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[linenum]
+
+  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+(register|static|extern|typedef)\b',
+            line):
+    error(filename, linenum, 'build/storage_class', 5,
+          'Storage class (static, extern, typedef, etc) should be first.')
+
+  if Match(r'\s*#\s*endif\s*[^/\s]+', line):
+    error(filename, linenum, '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(filename, linenum, '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(filename, linenum, 'build/deprecated', 3,
+          '>? and <? (max and min) operators are non-standard and deprecated.')
+
+  if Search(r'^\s*const\s*string\s*&\s*\w+\s*;', line):
+    # TODO(unknown): Could it be expanded safely to arbitrary references,
+    # without triggering too many false positives? The first
+    # attempt triggered 5 warnings for mostly benign code in the regtest, hence
+    # the restriction.
+    # Here's the original regexp, for the reference:
+    # type_name = r'\w+((\s*::\s*\w+)|(\s*<\s*\w+?\s*>))?'
+    # r'\s*const\s*' + type_name + '\s*&\s*\w+\s*;'
+    error(filename, linenum, 'runtime/member_string_references', 2,
+          'const string& members are dangerous. It is much better to use '
+          'alternatives, such as pointers or simple constants.')
+
+  # Everything else in this function operates on class declarations.
+  # Return early if the top of the nesting stack is not a class, or if
+  # the class head is not completed yet.
+  classinfo = nesting_state.InnermostClass()
+  if not classinfo or not classinfo.seen_open_brace:
+    return
+
+  # 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. Also look for
+  # non-single-argument constructors which are also technically valid, but
+  # strongly suggest something is wrong.
+  explicit_constructor_match = Match(
+      r'\s+(?:inline\s+)?(explicit\s+)?(?:inline\s+)?%s\s*'
+      r'\(((?:[^()]|\([^()]*\))*)\)'
+      % re.escape(base_classname),
+      line)
+
+  if explicit_constructor_match:
+    is_marked_explicit = explicit_constructor_match.group(1)
+
+    if not explicit_constructor_match.group(2):
+      constructor_args = []
+    else:
+      constructor_args = explicit_constructor_match.group(2).split(',')
+
+    # collapse arguments so that commas in template parameter lists and function
+    # argument parameter lists don't split arguments in two
+    i = 0
+    while i < len(constructor_args):
+      constructor_arg = constructor_args[i]
+      while (constructor_arg.count('<') > constructor_arg.count('>') or
+             constructor_arg.count('(') > constructor_arg.count(')')):
+        constructor_arg += ',' + constructor_args[i + 1]
+        del constructor_args[i + 1]
+      constructor_args[i] = constructor_arg
+      i += 1
+
+    defaulted_args = [arg for arg in constructor_args if '=' in arg]
+    noarg_constructor = (not constructor_args or  # empty arg list
+                         # 'void' arg specifier
+                         (len(constructor_args) == 1 and
+                          constructor_args[0].strip() == 'void'))
+    onearg_constructor = ((len(constructor_args) == 1 and  # exactly one arg
+                           not noarg_constructor) or
+                          # all but at most one arg defaulted
+                          (len(constructor_args) >= 1 and
+                           not noarg_constructor and
+                           len(defaulted_args) >= len(constructor_args) - 1))
+    initializer_list_constructor = bool(
+        onearg_constructor and
+        Search(r'\bstd\s*::\s*initializer_list\b', constructor_args[0]))
+    copy_constructor = bool(
+        onearg_constructor and
+        Match(r'(const\s+)?%s(\s*<[^>]*>)?(\s+const)?\s*(?:<\w+>\s*)?&'
+              % re.escape(base_classname), constructor_args[0].strip()))
+
+    if (not is_marked_explicit and
+        onearg_constructor and
+        not initializer_list_constructor and
+        not copy_constructor):
+      if defaulted_args:
+        error(filename, linenum, 'runtime/explicit', 5,
+              'Constructors callable with one argument '
+              'should be marked explicit.')
+      else:
+        error(filename, linenum, 'runtime/explicit', 5,
+              'Single-parameter constructors should be marked explicit.')
+    elif is_marked_explicit and not onearg_constructor:
+      if noarg_constructor:
+        error(filename, linenum, 'runtime/explicit', 5,
+              'Zero-parameter constructors should not be marked explicit.')
+      else:
+        error(filename, linenum, 'runtime/explicit', 0,
+              'Constructors that require multiple arguments '
+              'should not be marked explicit.')
+
+
+def CheckSpacingForFunctionCall(filename, clean_lines, linenum, error):
+  """Checks for the correctness of various spacing around function calls.
+
+  Args:
+    filename: The name of the current file.
+    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.
+  """
+  line = clean_lines.elided[linenum]
+
+  # Since function calls often occur inside if/for/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.
+  fncall = line    # if there's no control flow construct, look at whole line
+  for pattern in (r'\bif\s*\((.*)\)\s*{',
+                  r'\bfor\s*\((.*)\)\s*{',
+                  r'\bwhile\s*\((.*)\)\s*[{;]',
+                  r'\bswitch\s*\((.*)\)\s*{'):
+    match = Search(pattern, line)
+    if match:
+      fncall = match.group(1)    # look inside the parens for function calls
+      break
+
+  # Except in if/for/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|while|switch|return|new|delete|catch|sizeof)\b',
+                 fncall) and
+      # Ignore pointers/references to functions.
+      not Search(r' \([^)]+\)\([^)]*(\)|,$)', fncall) and
+      # Ignore pointers/references to arrays.
+      not Search(r' \([^)]+\)\[[^\]]+\]', fncall)):
+    if Search(r'\w\s*\(\s(?!\s*\\$)', fncall):      # a ( used for a fn call
+      error(filename, linenum, 'whitespace/parens', 4,
+            'Extra space after ( in function call')
+    elif Search(r'\(\s+(?!(\s*\\)|\()', fncall):
+      error(filename, linenum, 'whitespace/parens', 2,
+            'Extra space after (')
+    if (Search(r'\w\s+\(', fncall) and
+        not Search(r'#\s*define|typedef|using\s+\w+\s*=', fncall) and
+        not Search(r'\w\s+\((\w+::)*\*\w+\)\(', fncall) and
+        not Search(r'\bcase\s+\(', fncall)):
+      # TODO(unknown): Space after an operator function seem to be a common
+      # error, silence those for now by restricting them to highest verbosity.
+      if Search(r'\boperator_*\b', line):
+        error(filename, linenum, 'whitespace/parens', 0,
+              'Extra space before ( in function call')
+      else:
+        error(filename, linenum, 'whitespace/parens', 4,
+              'Extra space before ( in function call')
+    # If the ) is followed only by a newline or a { + newline, assume it's
+    # part of a control statement (if/while/etc), and don't complain
+    if Search(r'[^)]\s+\)\s*[^{\s]', fncall):
+      # If the closing parenthesis is preceded by only whitespaces,
+      # try to give a more descriptive error message.
+      if Search(r'^\s+\)', fncall):
+        error(filename, linenum, 'whitespace/parens', 2,
+              'Closing ) should be moved to the previous line')
+      else:
+        error(filename, linenum, 'whitespace/parens', 2,
+              'Extra space before )')
+
+
+def IsBlankLine(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 CheckForNamespaceIndentation(filename, nesting_state, clean_lines, line,
+                                 error):
+  is_namespace_indent_item = (
+      len(nesting_state.stack) > 1 and
+      nesting_state.stack[-1].check_namespace_indentation and
+      isinstance(nesting_state.previous_stack_top, _NamespaceInfo) and
+      nesting_state.previous_stack_top == nesting_state.stack[-2])
+
+  if ShouldCheckNamespaceIndentation(nesting_state, is_namespace_indent_item,
+                                     clean_lines.elided, line):
+    CheckItemIndentationInNamespace(filename, clean_lines.elided,
+                                    line, error)
+
+
+def CheckForFunctionLengths(filename, clean_lines, linenum,
+                            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
+
+  Uses a simplistic algorithm assuming other style guidelines
+  (especially spacing) are followed.
+  Only checks unindented functions, so class members are unchecked.
+  Trivial bodies are unchecked, so constructors with huge initializer lists
+  may be missed.
+  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:
+    filename: The name of the current file.
+    clean_lines: A CleansedLines instance containing the file.
+    linenum: 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[linenum]
+  joined_line = ''
+
+  starting_func = False
+  regexp = r'(\w(\w|::|\*|\&|\s)*)\('  # decls * & space::name( ...
+  match_result = Match(regexp, line)
+  if match_result:
+    # 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' or function_name == 'TEST_F' or (
+        not Match(r'[A-Z_]+$', function_name)):
+      starting_func = True
+
+  if starting_func:
+    body_found = False
+    for start_linenum in xrange(linenum, clean_lines.NumLines()):
+      start_line = lines[start_linenum]
+      joined_line += ' ' + start_line.lstrip()
+      if Search(r'(;|})', start_line):  # Declarations and trivial functions
+        body_found = True
+        break                              # ... ignore
+      elif Search(r'{', start_line):
+        body_found = True
+        function = Search(r'((\w|:)*)\(', line).group(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 += '()'
+        function_state.Begin(function)
+        break
+    if not body_found:
+      # No body for the function (or evidence of a non-function) was found.
+      error(filename, linenum, 'readability/fn_size', 5,
+            'Lint failed to find start of function body.')
+  elif Match(r'^\}\s*$', line):  # function end
+    function_state.Check(error, filename, linenum)
+    function_state.End()
+  elif not Match(r'^\s*$', line):
+    function_state.Count()  # Count non-blank/non-comment lines.
+
+
+_RE_PATTERN_TODO = re.compile(r'^//(\s*)TODO(\(.+?\))?:?(\s|$)?')
+
+
+def CheckComment(line, filename, linenum, next_line_start, error):
+  """Checks for common mistakes in comments.
+
+  Args:
+    line: The line in question.
+    filename: The name of the current file.
+    linenum: The number of the line to check.
+    next_line_start: The first non-whitespace column of the next line.
+    error: The function to call with any errors found.
+  """
+  commentpos = line.find('//')
+  if commentpos != -1:
+    # Check if the // may be in quotes.  If so, ignore it
+    # Comparisons made explicit for clarity -- pylint: disable=g-explicit-bool-comparison
+    if (line.count('"', 0, commentpos) -
+        line.count('\\"', 0, commentpos)) % 2 == 0:   # not in quotes
+      # Allow one space for new scopes, two spaces otherwise:
+      if (not (Match(r'^.*{ *//', line) and next_line_start == commentpos) and
+          ((commentpos >= 1 and
+            line[commentpos-1] not in string.whitespace) or
+           (commentpos >= 2 and
+            line[commentpos-2] not in string.whitespace))):
+        error(filename, linenum, 'whitespace/comments', 2,
+              'At least two spaces is best between code and comments')
+
+      # Checks for common mistakes in TODO comments.
+      comment = line[commentpos:]
+      match = _RE_PATTERN_TODO.match(comment)
+      if match:
+        # One whitespace is correct; zero whitespace is handled elsewhere.
+        leading_whitespace = match.group(1)
+        if len(leading_whitespace) > 1:
+          error(filename, linenum, 'whitespace/todo', 2,
+                'Too many spaces before TODO')
+
+        username = match.group(2)
+        if not username:
+          error(filename, linenum, 'readability/todo', 2,
+                'Missing username in TODO; it should look like '
+                '"// TODO(my_username): Stuff."')
+
+        middle_whitespace = match.group(3)
+        # Comparisons made explicit for correctness -- pylint: disable=g-explicit-bool-comparison
+        if middle_whitespace != ' ' and middle_whitespace != '':
+          error(filename, linenum, 'whitespace/todo', 2,
+                'TODO(my_username) should be followed by a space')
+
+      # If the comment contains an alphanumeric character, there
+      # should be a space somewhere between it and the // unless
+      # it's a /// or //! Doxygen comment.
+      if (Match(r'//[^ ]*\w', comment) and
+          not Match(r'(///|//\!)(\s+|$)', comment)):
+        error(filename, linenum, 'whitespace/comments', 4,
+              'Should have a space between // and comment')
+
+
+def CheckAccess(filename, clean_lines, linenum, nesting_state, error):
+  """Checks for improper use of DISALLOW* macros.
+
+  Args:
+    filename: The name of the current file.
+    clean_lines: A CleansedLines instance containing the file.
+    linenum: The number of the line to check.
+    nesting_state: A NestingState instance which maintains information about
+                   the current stack of nested blocks being parsed.
+    error: The function to call with any errors found.
+  """
+  line = clean_lines.elided[linenum]  # get rid of comments and strings
+
+  matched = Match((r'\s*(DISALLOW_COPY_AND_ASSIGN|'
+                   r'DISALLOW_IMPLICIT_CONSTRUCTORS)'), line)
+  if not matched:
+    return
+  if nesting_state.stack and isinstance(nesting_state.stack[-1], _ClassInfo):
+    if nesting_state.stack[-1].access != 'private':
+      error(filename, linenum, 'readability/constructors', 3,
+            '%s must be in the private: section' % matched.group(1))
+
+  else:
+    # Found DISALLOW* macro outside a class declaration, or perhaps it
+    # was used inside a function when it should have been part of the
+    # class declaration.  We could issue a warning here, but it
+    # probably resulted in a compiler error already.
+    pass
+
+
+def CheckSpacing(filename, clean_lines, linenum, nesting_state, 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 add a blank line
+  after public/protected/private, don't have too many blank lines in a row.
+
+  Args:
+    filename: The name of the current file.
+    clean_lines: A CleansedLines instance containing the file.
+    linenum: The number of the line to check.
+    nesting_state: A NestingState instance which maintains information about
+                   the current stack of nested blocks being parsed.
+    error: The function to call with any errors found.
+  """
+
+  # Don't use "elided" lines here, otherwise we can't check commented lines.
+  # Don't want to use "raw" either, because we don't want to check inside C++11
+  # raw strings,
+  raw = clean_lines.lines_without_raw_strings
+  line = raw[linenum]
+
+  # 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 '}'
+  #
+  # Skip all the blank line checks if we are immediately inside a
+  # namespace body.  In other words, don't issue blank line warnings
+  # for this block:
+  #   namespace {
+  #
+  #   }
+  #
+  # A warning about missing end of namespace comments will be issued instead.
+  #
+  # Also skip blank line checks for 'extern "C"' blocks, which are formatted
+  # like namespaces.
+  if (IsBlankLine(line) and
+      not nesting_state.InNamespaceBody() and
+      not nesting_state.InExternC()):
+    elided = clean_lines.elided
+    prev_line = elided[linenum - 1]
+    prevbrace = prev_line.rfind('{')
+    # TODO(unknown): 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 prevbrace != -1 and prev_line[prevbrace:].find('}') == -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', prev_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 = linenum-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*$|:)',
+                           prev_line)
+                     or Match(r' {4}:', prev_line))
+
+      if not exception:
+        error(filename, linenum, 'whitespace/blank_line', 2,
+              'Redundant blank line at the start of a code block '
+              'should be deleted.')
+    # 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 linenum + 1 < clean_lines.NumLines():
+      next_line = raw[linenum + 1]
+      if (next_line
+          and Match(r'\s*}', next_line)
+          and next_line.find('} else ') == -1):
+        error(filename, linenum, 'whitespace/blank_line', 3,
+              'Redundant blank line at the end of a code block '
+              'should be deleted.')
+
+    matched = Match(r'\s*(public|protected|private):', prev_line)
+    if matched:
+      error(filename, linenum, 'whitespace/blank_line', 3,
+            'Do not leave a blank line after "%s:"' % matched.group(1))
+
+  # Next, check comments
+  next_line_start = 0
+  if linenum + 1 < clean_lines.NumLines():
+    next_line = raw[linenum + 1]
+    next_line_start = len(next_line) - len(next_line.lstrip())
+  CheckComment(line, filename, linenum, next_line_start, error)
+
+  # get rid of comments and strings
+  line = clean_lines.elided[linenum]
+
+  # You shouldn't have spaces before your brackets, except maybe after
+  # 'delete []' or 'return []() {};'
+  if Search(r'\w\s+\[', line) and not Search(r'(?:delete|return)\s+\[', line):
+    error(filename, linenum, 'whitespace/braces', 5,
+          'Extra space before [')
+
+  # In range-based for, we wanted spaces before and after the colon, but
+  # not around "::" tokens that might appear.
+  if (Search(r'for *\(.*[^:]:[^: ]', line) or
+      Search(r'for *\(.*[^: ]:[^:]', line)):
+    error(filename, linenum, 'whitespace/forcolon', 2,
+          'Missing space around colon in range-based for loop')
+
+
+def CheckOperatorSpacing(filename, clean_lines, linenum, error):
+  """Checks for horizontal spacing around operators.
+
+  Args:
+    filename: The name of the current file.
+    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.
+  """
+  line = clean_lines.elided[linenum]
+
+  # Don't try to do spacing checks for operator methods.  Do this by
+  # replacing the troublesome characters with something else,
+  # preserving column position for all other characters.
+  #
+  # The replacement is done repeatedly to avoid false positives from
+  # operators that call operators.
+  while True:
+    match = Match(r'^(.*\boperator\b)(\S+)(\s*\(.*)$', line)
+    if match:
+      line = match.group(1) + ('_' * len(match.group(2))) + match.group(3)
+    else:
+      break
+
+  # We allow no-spaces around = within an if: "if ( (a=Foo()) == 0 )".
+  # Otherwise not.  Note we only check for non-spaces on *both* sides;
+  # sometimes people put non-spaces on one side when aligning ='s among
+  # many lines (not that this is behavior that I approve of...)
+  if ((Search(r'[\w.]=', line) or
+       Search(r'=[\w.]', line))
+      and not Search(r'\b(if|while|for) ', line)
+      # Operators taken from [lex.operators] in C++11 standard.
+      and not Search(r'(>=|<=|==|!=|&=|\^=|\|=|\+=|\*=|\/=|\%=)', line)
+      and not Search(r'operator=', line)):
+    error(filename, linenum, 'whitespace/operators', 4,
+          'Missing spaces around =')
+
+  # It's ok not to have spaces around binary operators like + - * /, but if
+  # there's too little whitespace, we get concerned.  It's hard to tell,
+  # though, so we punt on this one for now.  TODO.
+
+  # You should always have whitespace around binary operators.
+  #
+  # Check <= and >= first to avoid false positives with < and >, then
+  # check non-include lines for spacing around < and >.
+  #
+  # If the operator is followed by a comma, assume it's be used in a
+  # macro context and don't do any checks.  This avoids false
+  # positives.
+  #
+  # Note that && is not included here.  Those are checked separately
+  # in CheckRValueReference
+  match = Search(r'[^<>=!\s](==|!=|<=|>=|\|\|)[^<>=!\s,;\)]', line)
+  if match:
+    error(filename, linenum, 'whitespace/operators', 3,
+          'Missing spaces around %s' % match.group(1))
+  elif not Match(r'#.*include', line):
+    # Look for < that is not surrounded by spaces.  This is only
+    # triggered if both sides are missing spaces, even though
+    # technically should should flag if at least one side is missing a
+    # space.  This is done to avoid some false positives with shifts.
+    match = Match(r'^(.*[^\s<])<[^\s=<,]', line)
+    if match:
+      (_, _, end_pos) = CloseExpression(
+          clean_lines, linenum, len(match.group(1)))
+      if end_pos <= -1:
+        error(filename, linenum, 'whitespace/operators', 3,
+              'Missing spaces around <')
+
+    # Look for > that is not surrounded by spaces.  Similar to the
+    # above, we only trigger if both sides are missing spaces to avoid
+    # false positives with shifts.
+    match = Match(r'^(.*[^-\s>])>[^\s=>,]', line)
+    if match:
+      (_, _, start_pos) = ReverseCloseExpression(
+          clean_lines, linenum, len(match.group(1)))
+      if start_pos <= -1:
+        error(filename, linenum, 'whitespace/operators', 3,
+              'Missing spaces around >')
+
+  # We allow no-spaces around << when used like this: 10<<20, but
+  # not otherwise (particularly, not when used as streams)
+  #
+  # We also allow operators following an opening parenthesis, since
+  # those tend to be macros that deal with operators.
+  match = Search(r'(operator|[^\s(<])(?:L|UL|ULL|l|ul|ull)?<<([^\s,=<])', line)
+  if (match and not (match.group(1).isdigit() and match.group(2).isdigit()) and
+      not (match.group(1) == 'operator' and match.group(2) == ';')):
+    error(filename, linenum, 'whitespace/operators', 3,
+          'Missing spaces around <<')
+
+  # We allow no-spaces around >> for almost anything.  This is because
+  # C++11 allows ">>" to close nested templates, which accounts for
+  # most cases when ">>" is not followed by a space.
+  #
+  # We still warn on ">>" followed by alpha character, because that is
+  # likely due to ">>" being used for right shifts, e.g.:
+  #   value >> alpha
+  #
+  # When ">>" is used to close templates, the alphanumeric letter that
+  # follows would be part of an identifier, and there should still be
+  # a space separating the template type and the identifier.
+  #   type<type<type>> alpha
+  match = Search(r'>>[a-zA-Z_]', line)
+  if match:
+    error(filename, linenum, 'whitespace/operators', 3,
+          'Missing spaces around >>')
+
+  # There shouldn't be space around unary operators
+  match = Search(r'(!\s|~\s|[\s]--[\s;]|[\s]\+\+[\s;])', line)
+  if match:
+    error(filename, linenum, 'whitespace/operators', 4,
+          'Extra space for operator %s' % match.group(1))
+
+
+def CheckParenthesisSpacing(filename, clean_lines, linenum, error):
+  """Checks for horizontal spacing around parentheses.
+
+  Args:
+    filename: The name of the current file.
+    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.
+  """
+  line = clean_lines.elided[linenum]
+
+  # No spaces after an if, while, switch, or for
+  match = Search(r' (if\(|for\(|while\(|switch\()', line)
+  if match:
+    error(filename, linenum, 'whitespace/parens', 5,
+          'Missing space before ( in %s' % match.group(1))
+
+  # For if/for/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.
+  match = Search(r'\b(if|for|while|switch)\s*'
+                 r'\(([ ]*)(.).*[^ ]+([ ]*)\)\s*{\s*$',
+                 line)
+  if match:
+    if len(match.group(2)) != len(match.group(4)):
+      if not (match.group(3) == ';' and
+              len(match.group(2)) == 1 + len(match.group(4)) or
+              not match.group(2) and Search(r'\bfor\s*\(.*; \)', line)):
+        error(filename, linenum, 'whitespace/parens', 5,
+              'Mismatching spaces inside () in %s' % match.group(1))
+    if len(match.group(2)) not in [0, 1]:
+      error(filename, linenum, 'whitespace/parens', 5,
+            'Should have zero or one spaces inside ( and ) in %s' %
+            match.group(1))
+
+
+def CheckCommaSpacing(filename, clean_lines, linenum, error):
+  """Checks for horizontal spacing near commas and semicolons.
+
+  Args:
+    filename: The name of the current file.
+    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.
+  """
+  raw = clean_lines.lines_without_raw_strings
+  line = clean_lines.elided[linenum]
+
+  # You should always have a space after a comma (either as fn arg or operator)
+  #
+  # This does not apply when the non-space character following the
+  # comma is another comma, since the only time when that happens is
+  # for empty macro arguments.
+  #
+  # We run this check in two passes: first pass on elided lines to
+  # verify that lines contain missing whitespaces, second pass on raw
+  # lines to confirm that those missing whitespaces are not due to
+  # elided comments.
+  if (Search(r',[^,\s]', ReplaceAll(r'\boperator\s*,\s*\(', 'F(', line)) and
+      Search(r',[^,\s]', raw[linenum])):
+    error(filename, linenum, 'whitespace/comma', 3,
+          'Missing space after ,')
+
+  # You should always have a space after a semicolon
+  # except for few corner cases
+  # TODO(unknown): clarify if 'if (1) { return 1;}' is requires one more
+  # space after ;
+  if Search(r';[^\s};\\)/]', line):
+    error(filename, linenum, 'whitespace/semicolon', 3,
+          'Missing space after ;')
+
+
+def CheckBracesSpacing(filename, clean_lines, linenum, error):
+  """Checks for horizontal spacing near commas.
+
+  Args:
+    filename: The name of the current file.
+    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.
+  """
+  line = clean_lines.elided[linenum]
+
+  # Except after an opening paren, or after another opening brace (in case of
+  # an initializer list, for instance), 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.
+  match = Match(r'^(.*[^ ({>]){', line)
+  if match:
+    # Try a bit harder to check for brace initialization.  This
+    # happens in one of the following forms:
+    #   Constructor() : initializer_list_{} { ... }
+    #   Constructor{}.MemberFunction()
+    #   Type variable{};
+    #   FunctionCall(type{}, ...);
+    #   LastArgument(..., type{});
+    #   LOG(INFO) << type{} << " ...";
+    #   map_of_type[{...}] = ...;
+    #   ternary = expr ? new type{} : nullptr;
+    #   OuterTemplate<InnerTemplateConstructor<Type>{}>
+    #
+    # We check for the character following the closing brace, and
+    # silence the warning if it's one of those listed above, i.e.
+    # "{.;,)<>]:".
+    #
+    # To account for nested initializer list, we allow any number of
+    # closing braces up to "{;,)<".  We can't simply silence the
+    # warning on first sight of closing brace, because that would
+    # cause false negatives for things that are not initializer lists.
+    #   Silence this:         But not this:
+    #     Outer{                if (...) {
+    #       Inner{...}            if (...){  // Missing space before {
+    #     };                    }
+    #
+    # There is a false negative with this approach if people inserted
+    # spurious semicolons, e.g. "if (cond){};", but we will catch the
+    # spurious semicolon with a separate check.
+    (endline, endlinenum, endpos) = CloseExpression(
+        clean_lines, linenum, len(match.group(1)))
+    trailing_text = ''
+    if endpos > -1:
+      trailing_text = endline[endpos:]
+    for offset in xrange(endlinenum + 1,
+                         min(endlinenum + 3, clean_lines.NumLines() - 1)):
+      trailing_text += clean_lines.elided[offset]
+    if not Match(r'^[\s}]*[{.;,)<>\]:]', trailing_text):
+      error(filename, linenum, 'whitespace/braces', 5,
+            'Missing space before {')
+
+  # Make sure '} else {' has spaces.
+  if Search(r'}else', line):
+    error(filename, linenum, 'whitespace/braces', 5,
+          'Missing space before else')
+
+  # 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*$', line):
+    error(filename, linenum, 'whitespace/semicolon', 5,
+          'Semicolon defining empty statement. Use {} instead.')
+  elif Search(r'^\s*;\s*$', line):
+    error(filename, linenum, 'whitespace/semicolon', 5,
+          'Line contains only semicolon. If this should be an empty statement, '
+          'use {} instead.')
+  elif (Search(r'\s+;\s*$', line) and
+        not Search(r'\bfor\b', line)):
+    error(filename, linenum, 'whitespace/semicolon', 5,
+          'Extra space before last semicolon. If this should be an empty '
+          'statement, use {} instead.')
+
+
+def IsDecltype(clean_lines, linenum, column):
+  """Check if the token ending on (linenum, column) is decltype().
+
+  Args:
+    clean_lines: A CleansedLines instance containing the file.
+    linenum: the number of the line to check.
+    column: end column of the token to check.
+  Returns:
+    True if this token is decltype() expression, False otherwise.
+  """
+  (text, _, start_col) = ReverseCloseExpression(clean_lines, linenum, column)
+  if start_col < 0:
+    return False
+  if Search(r'\bdecltype\s*$', text[0:start_col]):
+    return True
+  return False
+
+
+def IsTemplateParameterList(clean_lines, linenum, column):
+  """Check if the token ending on (linenum, column) is the end of template<>.
+
+  Args:
+    clean_lines: A CleansedLines instance containing the file.
+    linenum: the number of the line to check.
+    column: end column of the token to check.
+  Returns:
+    True if this token is end of a template parameter list, False otherwise.
+  """
+  (_, startline, startpos) = ReverseCloseExpression(
+      clean_lines, linenum, column)
+  if (startpos > -1 and
+      Search(r'\btemplate\s*$', clean_lines.elided[startline][0:startpos])):
+    return True
+  return False
+
+
+def IsRValueType(typenames, clean_lines, nesting_state, linenum, column):
+  """Check if the token ending on (linenum, column) is a type.
+
+  Assumes that text to the right of the column is "&&" or a function
+  name.
+
+  Args:
+    typenames: set of type names from template-argument-list.
+    clean_lines: A CleansedLines instance containing the file.
+    nesting_state: A NestingState instance which maintains information about
+                   the current stack of nested blocks being parsed.
+    linenum: the number of the line to check.
+    column: end column of the token to check.
+  Returns:
+    True if this token is a type, False if we are not sure.
+  """
+  prefix = clean_lines.elided[linenum][0:column]
+
+  # Get one word to the left.  If we failed to do so, this is most
+  # likely not a type, since it's unlikely that the type name and "&&"
+  # would be split across multiple lines.
+  match = Match(r'^(.*)(\b\w+|[>*)&])\s*$', prefix)
+  if not match:
+    return False
+
+  # Check text following the token.  If it's "&&>" or "&&," or "&&...", it's
+  # most likely a rvalue reference used inside a template.
+  suffix = clean_lines.elided[linenum][column:]
+  if Match(r'&&\s*(?:[>,]|\.\.\.)', suffix):
+    return True
+
+  # Check for known types and end of templates:
+  #   int&& variable
+  #   vector<int>&& variable
+  #
+  # Because this function is called recursively, we also need to
+  # recognize pointer and reference types:
+  #   int* Function()
+  #   int& Function()
+  if (match.group(2) in typenames or
+      match.group(2) in ['char', 'char16_t', 'char32_t', 'wchar_t', 'bool',
+                         'short', 'int', 'long', 'signed', 'unsigned',
+                         'float', 'double', 'void', 'auto', '>', '*', '&']):
+    return True
+
+  # If we see a close parenthesis, look for decltype on the other side.
+  # decltype would unambiguously identify a type, anything else is
+  # probably a parenthesized expression and not a type.
+  if match.group(2) == ')':
+    return IsDecltype(
+        clean_lines, linenum, len(match.group(1)) + len(match.group(2)) - 1)
+
+  # Check for casts and cv-qualifiers.
+  #   match.group(1)  remainder
+  #   --------------  ---------
+  #   const_cast<     type&&
+  #   const           type&&
+  #   type            const&&
+  if Search(r'\b(?:const_cast\s*<|static_cast\s*<|dynamic_cast\s*<|'
+            r'reinterpret_cast\s*<|\w+\s)\s*$',
+            match.group(1)):
+    return True
+
+  # Look for a preceding symbol that might help differentiate the context.
+  # These are the cases that would be ambiguous:
+  #   match.group(1)  remainder
+  #   --------------  ---------
+  #   Call         (   expression &&
+  #   Declaration  (   type&&
+  #   sizeof       (   type&&
+  #   if           (   expression &&
+  #   while        (   expression &&
+  #   for          (   type&&
+  #   for(         ;   expression &&
+  #   statement    ;   type&&
+  #   block        {   type&&
+  #   constructor  {   expression &&
+  start = linenum
+  line = match.group(1)
+  match_symbol = None
+  while start >= 0:
+    # We want to skip over identifiers and commas to get to a symbol.
+    # Commas are skipped so that we can find the opening parenthesis
+    # for function parameter lists.
+    match_symbol = Match(r'^(.*)([^\w\s,])[\w\s,]*$', line)
+    if match_symbol:
+      break
+    start -= 1
+    line = clean_lines.elided[start]
+
+  if not match_symbol:
+    # Probably the first statement in the file is an rvalue reference
+    return True
+
+  if match_symbol.group(2) == '}':
+    # Found closing brace, probably an indicate of this:
+    #   block{} type&&
+    return True
+
+  if match_symbol.group(2) == ';':
+    # Found semicolon, probably one of these:
+    #   for(; expression &&
+    #   statement; type&&
+
+    # Look for the previous 'for(' in the previous lines.
+    before_text = match_symbol.group(1)
+    for i in xrange(start - 1, max(start - 6, 0), -1):
+      before_text = clean_lines.elided[i] + before_text
+    if Search(r'for\s*\([^{};]*$', before_text):
+      # This is the condition inside a for-loop
+      return False
+
+    # Did not find a for-init-statement before this semicolon, so this
+    # is probably a new statement and not a condition.
+    return True
+
+  if match_symbol.group(2) == '{':
+    # Found opening brace, probably one of these:
+    #   block{ type&& = ... ; }
+    #   constructor{ expression && expression }
+
+    # Look for a closing brace or a semicolon.  If we see a semicolon
+    # first, this is probably a rvalue reference.
+    line = clean_lines.elided[start][0:len(match_symbol.group(1)) + 1]
+    end = start
+    depth = 1
+    while True:
+      for ch in line:
+        if ch == ';':
+          return True
+        elif ch == '{':
+          depth += 1
+        elif ch == '}':
+          depth -= 1
+          if depth == 0:
+            return False
+      end += 1
+      if end >= clean_lines.NumLines():
+        break
+      line = clean_lines.elided[end]
+    # Incomplete program?
+    return False
+
+  if match_symbol.group(2) == '(':
+    # Opening parenthesis.  Need to check what's to the left of the
+    # parenthesis.  Look back one extra line for additional context.
+    before_text = match_symbol.group(1)
+    if linenum > 1:
+      before_text = clean_lines.elided[linenum - 1] + before_text
+    before_text = match_symbol.group(1)
+
+    # Patterns that are likely to be types:
+    #   [](type&&
+    #   for (type&&
+    #   sizeof(type&&
+    #   operator=(type&&
+    #
+    if Search(r'(?:\]|\bfor|\bsizeof|\boperator\s*\S+\s*)\s*$', before_text):
+      return True
+
+    # Patterns that are likely to be expressions:
+    #   if (expression &&
+    #   while (expression &&
+    #   : initializer(expression &&
+    #   , initializer(expression &&
+    #   ( FunctionCall(expression &&
+    #   + FunctionCall(expression &&
+    #   + (expression &&
+    #
+    # The last '+' represents operators such as '+' and '-'.
+    if Search(r'(?:\bif|\bwhile|[-+=%^(<!?:,&*]\s*)$', before_text):
+      return False
+
+    # Something else.  Check that tokens to the left look like
+    #   return_type function_name
+    match_func = Match(r'^(.*\S.*)\s+\w(?:\w|::)*(?:<[^<>]*>)?\s*$',
+                       match_symbol.group(1))
+    if match_func:
+      # Check for constructors, which don't have return types.
+      if Search(r'\b(?:explicit|inline)$', match_func.group(1)):
+        return True
+      implicit_constructor = Match(r'\s*(\w+)\((?:const\s+)?(\w+)', prefix)
+      if (implicit_constructor and
+          implicit_constructor.group(1) == implicit_constructor.group(2)):
+        return True
+      return IsRValueType(typenames, clean_lines, nesting_state, linenum,
+                          len(match_func.group(1)))
+
+    # Nothing before the function name.  If this is inside a block scope,
+    # this is probably a function call.
+    return not (nesting_state.previous_stack_top and
+                nesting_state.previous_stack_top.IsBlockInfo())
+
+  if match_symbol.group(2) == '>':
+    # Possibly a closing bracket, check that what's on the other side
+    # looks like the start of a template.
+    return IsTemplateParameterList(
+        clean_lines, start, len(match_symbol.group(1)))
+
+  # Some other symbol, usually something like "a=b&&c".  This is most
+  # likely not a type.
+  return False
+
+
+def IsDeletedOrDefault(clean_lines, linenum):
+  """Check if current constructor or operator is deleted or default.
+
+  Args:
+    clean_lines: A CleansedLines instance containing the file.
+    linenum: The number of the line to check.
+  Returns:
+    True if this is a deleted or default constructor.
+  """
+  open_paren = clean_lines.elided[linenum].find('(')
+  if open_paren < 0:
+    return False
+  (close_line, _, close_paren) = CloseExpression(
+      clean_lines, linenum, open_paren)
+  if close_paren < 0:
+    return False
+  return Match(r'\s*=\s*(?:delete|default)\b', close_line[close_paren:])
+
+
+def IsRValueAllowed(clean_lines, linenum, typenames):
+  """Check if RValue reference is allowed on a particular line.
+
+  Args:
+    clean_lines: A CleansedLines instance containing the file.
+    linenum: The number of the line to check.
+    typenames: set of type names from template-argument-list.
+  Returns:
+    True if line is within the region where RValue references are allowed.
+  """
+  # Allow region marked by PUSH/POP macros
+  for i in xrange(linenum, 0, -1):
+    line = clean_lines.elided[i]
+    if Match(r'GOOGLE_ALLOW_RVALUE_REFERENCES_(?:PUSH|POP)', line):
+      if not line.endswith('PUSH'):
+        return False
+      for j in xrange(linenum, clean_lines.NumLines(), 1):
+        line = clean_lines.elided[j]
+        if Match(r'GOOGLE_ALLOW_RVALUE_REFERENCES_(?:PUSH|POP)', line):
+          return line.endswith('POP')
+
+  # Allow operator=
+  line = clean_lines.elided[linenum]
+  if Search(r'\boperator\s*=\s*\(', line):
+    return IsDeletedOrDefault(clean_lines, linenum)
+
+  # Allow constructors
+  match = Match(r'\s*(?:[\w<>]+::)*([\w<>]+)\s*::\s*([\w<>]+)\s*\(', line)
+  if match and match.group(1) == match.group(2):
+    return IsDeletedOrDefault(clean_lines, linenum)
+  if Search(r'\b(?:explicit|inline)\s+[\w<>]+\s*\(', line):
+    return IsDeletedOrDefault(clean_lines, linenum)
+
+  if Match(r'\s*[\w<>]+\s*\(', line):
+    previous_line = 'ReturnType'
+    if linenum > 0:
+      previous_line = clean_lines.elided[linenum - 1]
+    if Match(r'^\s*$', previous_line) or Search(r'[{}:;]\s*$', previous_line):
+      return IsDeletedOrDefault(clean_lines, linenum)
+
+  # Reject types not mentioned in template-argument-list
+  while line:
+    match = Match(r'^.*?(\w+)\s*&&(.*)$', line)
+    if not match:
+      break
+    if match.group(1) not in typenames:
+      return False
+    line = match.group(2)
+
+  # All RValue types that were in template-argument-list should have
+  # been removed by now.  Those were allowed, assuming that they will
+  # be forwarded.
+  #
+  # If there are no remaining RValue types left (i.e. types that were
+  # not found in template-argument-list), flag those as not allowed.
+  return line.find('&&') < 0
+
+
+def GetTemplateArgs(clean_lines, linenum):
+  """Find list of template arguments associated with this function declaration.
+
+  Args:
+    clean_lines: A CleansedLines instance containing the file.
+    linenum: Line number containing the start of the function declaration,
+             usually one line after the end of the template-argument-list.
+  Returns:
+    Set of type names, or empty set if this does not appear to have
+    any template parameters.
+  """
+  # Find start of function
+  func_line = linenum
+  while func_line > 0:
+    line = clean_lines.elided[func_line]
+    if Match(r'^\s*$', line):
+      return set()
+    if line.find('(') >= 0:
+      break
+    func_line -= 1
+  if func_line == 0:
+    return set()
+
+  # Collapse template-argument-list into a single string
+  argument_list = ''
+  match = Match(r'^(\s*template\s*)<', clean_lines.elided[func_line])
+  if match:
+    # template-argument-list on the same line as function name
+    start_col = len(match.group(1))
+    _, end_line, end_col = CloseExpression(clean_lines, func_line, start_col)
+    if end_col > -1 and end_line == func_line:
+      start_col += 1  # Skip the opening bracket
+      argument_list = clean_lines.elided[func_line][start_col:end_col]
+
+  elif func_line > 1:
+    # template-argument-list one line before function name
+    match = Match(r'^(.*)>\s*$', clean_lines.elided[func_line - 1])
+    if match:
+      end_col = len(match.group(1))
+      _, start_line, start_col = ReverseCloseExpression(
+          clean_lines, func_line - 1, end_col)
+      if start_col > -1:
+        start_col += 1  # Skip the opening bracket
+        while start_line < func_line - 1:
+          argument_list += clean_lines.elided[start_line][start_col:]
+          start_col = 0
+          start_line += 1
+        argument_list += clean_lines.elided[func_line - 1][start_col:end_col]
+
+  if not argument_list:
+    return set()
+
+  # Extract type names
+  typenames = set()
+  while True:
+    match = Match(r'^[,\s]*(?:typename|class)(?:\.\.\.)?\s+(\w+)(.*)$',
+                  argument_list)
+    if not match:
+      break
+    typenames.add(match.group(1))
+    argument_list = match.group(2)
+  return typenames
+
+
+def CheckRValueReference(filename, clean_lines, linenum, nesting_state, error):
+  """Check for rvalue references.
+
+  Args:
+    filename: The name of the current file.
+    clean_lines: A CleansedLines instance containing the file.
+    linenum: The number of the line to check.
+    nesting_state: A NestingState instance which maintains information about
+                   the current stack of nested blocks being parsed.
+    error: The function to call with any errors found.
+  """
+  # Find lines missing spaces around &&.
+  # TODO(unknown): currently we don't check for rvalue references
+  # with spaces surrounding the && to avoid false positives with
+  # boolean expressions.
+  line = clean_lines.elided[linenum]
+  match = Match(r'^(.*\S)&&', line)
+  if not match:
+    match = Match(r'(.*)&&\S', line)
+  if (not match) or '(&&)' in line or Search(r'\boperator\s*$', match.group(1)):
+    return
+
+  # Either poorly formed && or an rvalue reference, check the context
+  # to get a more accurate error message.  Mostly we want to determine
+  # if what's to the left of "&&" is a type or not.
+  typenames = GetTemplateArgs(clean_lines, linenum)
+  and_pos = len(match.group(1))
+  if IsRValueType(typenames, clean_lines, nesting_state, linenum, and_pos):
+    if not IsRValueAllowed(clean_lines, linenum, typenames):
+      error(filename, linenum, 'build/c++11', 3,
+            'RValue references are an unapproved C++ feature.')
+  else:
+    error(filename, linenum, 'whitespace/operators', 3,
+          'Missing spaces around &&')
+
+
+def CheckSectionSpacing(filename, clean_lines, class_info, linenum, error):
+  """Checks for additional blank line issues related to sections.
+
+  Currently the only thing checked here is blank line before protected/private.
+
+  Args:
+    filename: The name of the current file.
+    clean_lines: A CleansedLines instance containing the file.
+    class_info: A _ClassInfo objects.
+    linenum: The number of the line to check.
+    error: The function to call with any errors found.
+  """
+  # Skip checks if the class is small, where small means 25 lines or less.
+  # 25 lines seems like a good cutoff since that's the usual height of
+  # terminals, and any class that can't fit in one screen can't really
+  # be considered "small".
+  #
+  # Also skip checks if we are on the first line.  This accounts for
+  # classes that look like
+  #   class Foo { public: ... };
+  #
+  # If we didn't find the end of the class, last_line would be zero,
+  # and the check will be skipped by the first condition.
+  if (class_info.last_line - class_info.starting_linenum <= 24 or
+      linenum <= class_info.starting_linenum):
+    return
+
+  matched = Match(r'\s*(public|protected|private):', clean_lines.lines[linenum])
+  if matched:
+    # Issue warning if the line before public/protected/private was
+    # not a blank line, but don't do this if the previous line contains
+    # "class" or "struct".  This can happen two ways:
+    #  - We are at the beginning of the class.
+    #  - We are forward-declaring an inner class that is semantically
+    #    private, but needed to be public for implementation reasons.
+    # Also ignores cases where the previous line ends with a backslash as can be
+    # common when defining classes in C macros.
+    prev_line = clean_lines.lines[linenum - 1]
+    if (not IsBlankLine(prev_line) and
+        not Search(r'\b(class|struct)\b', prev_line) and
+        not Search(r'\\$', prev_line)):
+      # Try a bit harder to find the beginning of the class.  This is to
+      # account for multi-line base-specifier lists, e.g.:
+      #   class Derived
+      #       : public Base {
+      end_class_head = class_info.starting_linenum
+      for i in range(class_info.starting_linenum, linenum):
+        if Search(r'\{\s*$', clean_lines.lines[i]):
+          end_class_head = i
+          break
+      if end_class_head < linenum - 1:
+        error(filename, linenum, 'whitespace/blank_line', 3,
+              '"%s:" should be preceded by a blank line' % matched.group(1))
+
+
+def GetPreviousNonBlankLine(clean_lines, linenum):
+  """Return the most recent non-blank line and its line number.
+
+  Args:
+    clean_lines: A CleansedLines instance containing the file contents.
+    linenum: The number of the line to check.
+
+  Returns:
+    A tuple with two elements.  The first element is the contents of the last
+    non-blank line before the current line, or the empty string if this is the
+    first non-blank line.  The second is the line number of that line, or -1
+    if this is the first non-blank line.
+  """
+
+  prevlinenum = linenum - 1
+  while prevlinenum >= 0:
+    prevline = clean_lines.elided[prevlinenum]
+    if not IsBlankLine(prevline):     # if not a blank line...
+      return (prevline, prevlinenum)
+    prevlinenum -= 1
+  return ('', -1)
+
+
+def CheckBraces(filename, clean_lines, linenum, error):
+  """Looks for misplaced braces (e.g. at the end of line).
+
+  Args:
+    filename: The name of the current file.
+    clean_lines: A CleansedLines instance containing the file.
+    linenum: The number of the line to check.
+    error: The function to call with any errors found.
+  """
+
+  line = clean_lines.elided[linenum]        # get rid of comments and strings
+
+  if Match(r'\s*{\s*$', line):
+    # We allow an open brace to start a line in the case where someone is using
+    # braces in a block to explicitly create a new scope, which is commonly used
+    # to control the lifetime of stack-allocated variables.  Braces are also
+    # used for brace initializers inside function calls.  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 '}', or if the
+    # previous line starts a preprocessor block.
+    prevline = GetPreviousNonBlankLine(clean_lines, linenum)[0]
+    if (not Search(r'[,;:}{(]\s*$', prevline) and
+        not Match(r'\s*#', prevline)):
+      error(filename, linenum, 'whitespace/braces', 4,
+            '{ should almost always be at the end of the previous line')
+
+  # An else clause should be on the same line as the preceding closing brace.
+  if Match(r'\s*else\b\s*(?:if\b|\{|$)', line):
+    prevline = GetPreviousNonBlankLine(clean_lines, linenum)[0]
+    if Match(r'\s*}\s*$', prevline):
+      error(filename, linenum, 'whitespace/newline', 4,
+            'An else should appear on the same line as the preceding }')
+
+  # If braces come on one side of an else, they should be on both.
+  # However, we have to worry about "else if" that spans multiple lines!
+  if Search(r'else if\s*\(', line):       # could be multi-line if
+    brace_on_left = bool(Search(r'}\s*else if\s*\(', line))
+    # find the ( after the if
+    pos = line.find('else if')
+    pos = line.find('(', pos)
+    if pos > 0:
+      (endline, _, endpos) = CloseExpression(clean_lines, linenum, pos)
+      brace_on_right = endline[endpos:].find('{') != -1
+      if brace_on_left != brace_on_right:    # must be brace after if
+        error(filename, linenum, 'readability/braces', 5,
+              'If an else has a brace on one side, it should have it on both')
+  elif Search(r'}\s*else[^{]*$', line) or Match(r'[^}]*else\s*{', line):
+    error(filename, linenum, 'readability/braces', 5,
+          'If an else has a brace on one side, it should have it on both')
+
+  # 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(filename, linenum, '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(filename, linenum, 'whitespace/newline', 4,
+          'do/while clauses should not be on a single line')
+
+  # Check single-line if/else bodies. The style guide says 'curly braces are not
+  # required for single-line statements'. We additionally allow multi-line,
+  # single statements, but we reject anything with more than one semicolon in
+  # it. This means that the first semicolon after the if should be at the end of
+  # its line, and the line after that should have an indent level equal to or
+  # lower than the if. We also check for ambiguous if/else nesting without
+  # braces.
+  if_else_match = Search(r'\b(if\s*\(|else\b)', line)
+  if if_else_match and not Match(r'\s*#', line):
+    if_indent = GetIndentLevel(line)
+    endline, endlinenum, endpos = line, linenum, if_else_match.end()
+    if_match = Search(r'\bif\s*\(', line)
+    if if_match:
+      # This could be a multiline if condition, so find the end first.
+      pos = if_match.end() - 1
+      (endline, endlinenum, endpos) = CloseExpression(clean_lines, linenum, pos)
+    # Check for an opening brace, either directly after the if or on the next
+    # line. If found, this isn't a single-statement conditional.
+    if (not Match(r'\s*{', endline[endpos:])
+        and not (Match(r'\s*$', endline[endpos:])
+                 and endlinenum < (len(clean_lines.elided) - 1)
+                 and Match(r'\s*{', clean_lines.elided[endlinenum + 1]))):
+      while (endlinenum < len(clean_lines.elided)
+             and ';' not in clean_lines.elided[endlinenum][endpos:]):
+        endlinenum += 1
+        endpos = 0
+      if endlinenum < len(clean_lines.elided):
+        endline = clean_lines.elided[endlinenum]
+        # We allow a mix of whitespace and closing braces (e.g. for one-liner
+        # methods) and a single \ after the semicolon (for macros)
+        endpos = endline.find(';')
+        if not Match(r';[\s}]*(\\?)$', endline[endpos:]):
+          # Semicolon isn't the last character, there's something trailing.
+          # Output a warning if the semicolon is not contained inside
+          # a lambda expression.
+          if not Match(r'^[^{};]*\[[^\[\]]*\][^{}]*\{[^{}]*\}\s*\)*[;,]\s*$',
+                       endline):
+            error(filename, linenum, 'readability/braces', 4,
+                  'If/else bodies with multiple statements require braces')
+        elif endlinenum < len(clean_lines.elided) - 1:
+          # Make sure the next line is dedented
+          next_line = clean_lines.elided[endlinenum + 1]
+          next_indent = GetIndentLevel(next_line)
+          # With ambiguous nested if statements, this will error out on the
+          # if that *doesn't* match the else, regardless of whether it's the
+          # inner one or outer one.
+          if (if_match and Match(r'\s*else\b', next_line)
+              and next_indent != if_indent):
+            error(filename, linenum, 'readability/braces', 4,
+                  'Else clause should be indented at the same level as if. '
+                  'Ambiguous nested if/else chains require braces.')
+          elif next_indent > if_indent:
+            error(filename, linenum, 'readability/braces', 4,
+                  'If/else bodies with multiple statements require braces')
+
+
+def CheckTrailingSemicolon(filename, clean_lines, linenum, error):
+  """Looks for redundant trailing semicolon.
+
+  Args:
+    filename: The name of the current file.
+    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.
+  """
+
+  line = clean_lines.elided[linenum]
+
+  # Block bodies should not be followed by a semicolon.  Due to C++11
+  # brace initialization, there are more places where semicolons are
+  # required than not, so we use a whitelist approach to check these
+  # rather than a blacklist.  These are the places where "};" should
+  # be replaced by just "}":
+  # 1. Some flavor of block following closing parenthesis:
+  #    for (;;) {};
+  #    while (...) {};
+  #    switch (...) {};
+  #    Function(...) {};
+  #    if (...) {};
+  #    if (...) else if (...) {};
+  #
+  # 2. else block:
+  #    if (...) else {};
+  #
+  # 3. const member function:
+  #    Function(...) const {};
+  #
+  # 4. Block following some statement:
+  #    x = 42;
+  #    {};
+  #
+  # 5. Block at the beginning of a function:
+  #    Function(...) {
+  #      {};
+  #    }
+  #
+  #    Note that naively checking for the preceding "{" will also match
+  #    braces inside multi-dimensional arrays, but this is fine since
+  #    that expression will not contain semicolons.
+  #
+  # 6. Block following another block:
+  #    while (true) {}
+  #    {};
+  #
+  # 7. End of namespaces:
+  #    namespace {};
+  #
+  #    These semicolons seems far more common than other kinds of
+  #    redundant semicolons, possibly due to people converting classes
+  #    to namespaces.  For now we do not warn for this case.
+  #
+  # Try matching case 1 first.
+  match = Match(r'^(.*\)\s*)\{', line)
+  if match:
+    # Matched closing parenthesis (case 1).  Check the token before the
+    # matching opening parenthesis, and don't warn if it looks like a
+    # macro.  This avoids these false positives:
+    #  - macro that defines a base class
+    #  - multi-line macro that defines a base class
+    #  - macro that defines the whole class-head
+    #
+    # But we still issue warnings for macros that we know are safe to
+    # warn, specifically:
+    #  - TEST, TEST_F, TEST_P, MATCHER, MATCHER_P
+    #  - TYPED_TEST
+    #  - INTERFACE_DEF
+    #  - EXCLUSIVE_LOCKS_REQUIRED, SHARED_LOCKS_REQUIRED, LOCKS_EXCLUDED:
+    #
+    # We implement a whitelist of safe macros instead of a blacklist of
+    # unsafe macros, even though the latter appears less frequently in
+    # google code and would have been easier to implement.  This is because
+    # the downside for getting the whitelist wrong means some extra
+    # semicolons, while the downside for getting the blacklist wrong
+    # would result in compile errors.
+    #
+    # In addition to macros, we also don't want to warn on
+    #  - Compound literals
+    #  - Lambdas
+    #  - alignas specifier with anonymous structs:
+    closing_brace_pos = match.group(1).rfind(')')
+    opening_parenthesis = ReverseCloseExpression(
+        clean_lines, linenum, closing_brace_pos)
+    if opening_parenthesis[2] > -1:
+      line_prefix = opening_parenthesis[0][0:opening_parenthesis[2]]
+      macro = Search(r'\b([A-Z_]+)\s*$', line_prefix)
+      func = Match(r'^(.*\])\s*$', line_prefix)
+      if ((macro and
+           macro.group(1) not in (
+               'TEST', 'TEST_F', 'MATCHER', 'MATCHER_P', 'TYPED_TEST',
+               'EXCLUSIVE_LOCKS_REQUIRED', 'SHARED_LOCKS_REQUIRED',
+               'LOCKS_EXCLUDED', 'INTERFACE_DEF')) or
+          (func and not Search(r'\boperator\s*\[\s*\]', func.group(1))) or
+          Search(r'\b(?:struct|union)\s+alignas\s*$', line_prefix) or
+          Search(r'\s+=\s*$', line_prefix)):
+        match = None
+    if (match and
+        opening_parenthesis[1] > 1 and
+        Search(r'\]\s*$', clean_lines.elided[opening_parenthesis[1] - 1])):
+      # Multi-line lambda-expression
+      match = None
+
+  else:
+    # Try matching cases 2-3.
+    match = Match(r'^(.*(?:else|\)\s*const)\s*)\{', line)
+    if not match:
+      # Try matching cases 4-6.  These are always matched on separate lines.
+      #
+      # Note that we can't simply concatenate the previous line to the
+      # current line and do a single match, otherwise we may output
+      # duplicate warnings for the blank line case:
+      #   if (cond) {
+      #     // blank line
+      #   }
+      prevline = GetPreviousNonBlankLine(clean_lines, linenum)[0]
+      if prevline and Search(r'[;{}]\s*$', prevline):
+        match = Match(r'^(\s*)\{', line)
+
+  # Check matching closing brace
+  if match:
+    (endline, endlinenum, endpos) = CloseExpression(
+        clean_lines, linenum, len(match.group(1)))
+    if endpos > -1 and Match(r'^\s*;', endline[endpos:]):
+      # Current {} pair is eligible for semicolon check, and we have found
+      # the redundant semicolon, output warning here.
+      #
+      # Note: because we are scanning forward for opening braces, and
+      # outputting warnings for the matching closing brace, if there are
+      # nested blocks with trailing semicolons, we will get the error
+      # messages in reversed order.
+      error(filename, endlinenum, 'readability/braces', 4,
+            "You don't need a ; after a }")
+
+
+def CheckEmptyBlockBody(filename, clean_lines, linenum, error):
+  """Look for empty loop/conditional body with only a single semicolon.
+
+  Args:
+    filename: The name of the current file.
+    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.
+  """
+
+  # Search for loop keywords at the beginning of the line.  Because only
+  # whitespaces are allowed before the keywords, this will also ignore most
+  # do-while-loops, since those lines should start with closing brace.
+  #
+  # We also check "if" blocks here, since an empty conditional block
+  # is likely an error.
+  line = clean_lines.elided[linenum]
+  matched = Match(r'\s*(for|while|if)\s*\(', line)
+  if matched:
+    # Find the end of the conditional expression
+    (end_line, end_linenum, end_pos) = CloseExpression(
+        clean_lines, linenum, line.find('('))
+
+    # Output warning if what follows the condition expression is a semicolon.
+    # No warning for all other cases, including whitespace or newline, since we
+    # have a separate check for semicolons preceded by whitespace.
+    if end_pos >= 0 and Match(r';', end_line[end_pos:]):
+      if matched.group(1) == 'if':
+        error(filename, end_linenum, 'whitespace/empty_conditional_body', 5,
+              'Empty conditional bodies should use {}')
+      else:
+        error(filename, end_linenum, 'whitespace/empty_loop_body', 5,
+              'Empty loop bodies should use {} or continue')
+
+
+def FindCheckMacro(line):
+  """Find a replaceable CHECK-like macro.
+
+  Args:
+    line: line to search on.
+  Returns:
+    (macro name, start position), or (None, -1) if no replaceable
+    macro is found.
+  """
+  for macro in _CHECK_MACROS:
+    i = line.find(macro)
+    if i >= 0:
+      # Find opening parenthesis.  Do a regular expression match here
+      # to make sure that we are matching the expected CHECK macro, as
+      # opposed to some other macro that happens to contain the CHECK
+      # substring.
+      matched = Match(r'^(.*\b' + macro + r'\s*)\(', line)
+      if not matched:
+        continue
+      return (macro, len(matched.group(1)))
+  return (None, -1)
+
+
+def CheckCheck(filename, clean_lines, linenum, error):
+  """Checks the use of CHECK and EXPECT macros.
+
+  Args:
+    filename: The name of the current file.
+    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.
+  """
+
+  # Decide the set of replacement macros that should be suggested
+  lines = clean_lines.elided
+  (check_macro, start_pos) = FindCheckMacro(lines[linenum])
+  if not check_macro:
+    return
+
+  # Find end of the boolean expression by matching parentheses
+  (last_line, end_line, end_pos) = CloseExpression(
+      clean_lines, linenum, start_pos)
+  if end_pos < 0:
+    return
+
+  # If the check macro is followed by something other than a
+  # semicolon, assume users will log their own custom error messages
+  # and don't suggest any replacements.
+  if not Match(r'\s*;', last_line[end_pos:]):
+    return
+
+  if linenum == end_line:
+    expression = lines[linenum][start_pos + 1:end_pos - 1]
+  else:
+    expression = lines[linenum][start_pos + 1:]
+    for i in xrange(linenum + 1, end_line):
+      expression += lines[i]
+    expression += last_line[0:end_pos - 1]
+
+  # Parse expression so that we can take parentheses into account.
+  # This avoids false positives for inputs like "CHECK((a < 4) == b)",
+  # which is not replaceable by CHECK_LE.
+  lhs = ''
+  rhs = ''
+  operator = None
+  while expression:
+    matched = Match(r'^\s*(<<|<<=|>>|>>=|->\*|->|&&|\|\||'
+                    r'==|!=|>=|>|<=|<|\()(.*)$', expression)
+    if matched:
+      token = matched.group(1)
+      if token == '(':
+        # Parenthesized operand
+        expression = matched.group(2)
+        (end, _) = FindEndOfExpressionInLine(expression, 0, ['('])
+        if end < 0:
+          return  # Unmatched parenthesis
+        lhs += '(' + expression[0:end]
+        expression = expression[end:]
+      elif token in ('&&', '||'):
+        # Logical and/or operators.  This means the expression
+        # contains more than one term, for example:
+        #   CHECK(42 < a && a < b);
+        #
+        # These are not replaceable with CHECK_LE, so bail out early.
+        return
+      elif token in ('<<', '<<=', '>>', '>>=', '->*', '->'):
+        # Non-relational operator
+        lhs += token
+        expression = matched.group(2)
+      else:
+        # Relational operator
+        operator = token
+        rhs = matched.group(2)
+        break
+    else:
+      # Unparenthesized operand.  Instead of appending to lhs one character
+      # at a time, we do another regular expression match to consume several
+      # characters at once if possible.  Trivial benchmark shows that this
+      # is more efficient when the operands are longer than a single
+      # character, which is generally the case.
+      matched = Match(r'^([^-=!<>()&|]+)(.*)$', expression)
+      if not matched:
+        matched = Match(r'^(\s*\S)(.*)$', expression)
+        if not matched:
+          break
+      lhs += matched.group(1)
+      expression = matched.group(2)
+
+  # Only apply checks if we got all parts of the boolean expression
+  if not (lhs and operator and rhs):
+    return
+
+  # Check that rhs do not contain logical operators.  We already know
+  # that lhs is fine since the loop above parses out && and ||.
+  if rhs.find('&&') > -1 or rhs.find('||') > -1:
+    return
+
+  # At least one of the operands must be a constant literal.  This is
+  # to avoid suggesting replacements for unprintable things like
+  # CHECK(variable != iterator)
+  #
+  # The following pattern matches decimal, hex integers, strings, and
+  # characters (in that order).
+  lhs = lhs.strip()
+  rhs = rhs.strip()
+  match_constant = r'^([-+]?(\d+|0[xX][0-9a-fA-F]+)[lLuU]{0,3}|".*"|\'.*\')$'
+  if Match(match_constant, lhs) or Match(match_constant, rhs):
+    # Note: since we know both lhs and rhs, we can provide a more
+    # descriptive error message like:
+    #   Consider using CHECK_EQ(x, 42) instead of CHECK(x == 42)
+    # Instead of:
+    #   Consider using CHECK_EQ instead of CHECK(a == b)
+    #
+    # We are still keeping the less descriptive message because if lhs
+    # or rhs gets long, the error message might become unreadable.
+    error(filename, linenum, 'readability/check', 2,
+          'Consider using %s instead of %s(a %s b)' % (
+              _CHECK_REPLACEMENT[check_macro][operator],
+              check_macro, operator))
+
+
+def CheckAltTokens(filename, clean_lines, linenum, error):
+  """Check alternative keywords being used in boolean expressions.
+
+  Args:
+    filename: The name of the current file.
+    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.
+  """
+  line = clean_lines.elided[linenum]
+
+  # Avoid preprocessor lines
+  if Match(r'^\s*#', line):
+    return
+
+  # Last ditch effort to avoid multi-line comments.  This will not help
+  # if the comment started before the current line or ended after the
+  # current line, but it catches most of the false positives.  At least,
+  # it provides a way to workaround this warning for people who use
+  # multi-line comments in preprocessor macros.
+  #
+  # TODO(unknown): remove this once cpplint has better support for
+  # multi-line comments.
+  if line.find('/*') >= 0 or line.find('*/') >= 0:
+    return
+
+  for match in _ALT_TOKEN_REPLACEMENT_PATTERN.finditer(line):
+    error(filename, linenum, 'readability/alt_tokens', 2,
+          'Use operator %s instead of %s' % (
+              _ALT_TOKEN_REPLACEMENT[match.group(1)], match.group(1)))
+
+
+def GetLineWidth(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 uc in unicodedata.normalize('NFC', line):
+      if unicodedata.east_asian_width(uc) in ('W', 'F'):
+        width += 2
+      elif not unicodedata.combining(uc):
+        width += 1
+    return width
+  else:
+    return len(line)
+
+
+def CheckStyle(filename, clean_lines, linenum, file_extension, nesting_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 2-space indents, line lengths,
+  tab usage, spaces inside code, etc.
+
+  Args:
+    filename: The name of the current file.
+    clean_lines: A CleansedLines instance containing the file.
+    linenum: The number of the line to check.
+    file_extension: The extension (without the dot) of the filename.
+    nesting_state: A NestingState instance which maintains information about
+                   the current stack of nested blocks being parsed.
+    error: The function to call with any errors found.
+  """
+
+  # Don't use "elided" lines here, otherwise we can't check commented lines.
+  # Don't want to use "raw" either, because we don't want to check inside C++11
+  # raw strings,
+  raw_lines = clean_lines.lines_without_raw_strings
+  line = raw_lines[linenum]
+
+  if line.find('\t') != -1:
+    error(filename, linenum, 'whitespace/tab', 1,
+          'Tab found; better to use spaces')
+
+  # One or three blank spaces at the beginning of the line is weird; it's
+  # hard to reconcile that with 2-space indents.
+  # NOTE: here are the conditions rob pike used for his tests.  Mine aren't
+  # as sophisticated, but it may be worth becoming so:  RLENGTH==initial_spaces
+  # if(RLENGTH > 20) complain = 0;
+  # if(match($0, " +(error|private|public|protected):")) complain = 0;
+  # if(match(prev, "&& *$")) complain = 0;
+  # if(match(prev, "\\|\\| *$")) complain = 0;
+  # if(match(prev, "[\",=><] *$")) complain = 0;
+  # if(match($0, " <<")) complain = 0;
+  # if(match(prev, " +for \\(")) complain = 0;
+  # if(prevodd && match(prevprev, " +for \\(")) complain = 0;
+  scope_or_label_pattern = r'\s*\w+\s*:\s*\\?$'
+  classinfo = nesting_state.InnermostClass()
+  initial_spaces = 0
+  cleansed_line = clean_lines.elided[linenum]
+  while initial_spaces < len(line) and line[initial_spaces] == ' ':
+    initial_spaces += 1
+  if line and line[-1].isspace():
+    error(filename, linenum, 'whitespace/end_of_line', 4,
+          'Line ends in whitespace.  Consider deleting these extra spaces.')
+  # There are certain situations we allow one space, notably for
+  # section labels, and also lines containing multi-line raw strings.
+  elif ((initial_spaces == 1 or initial_spaces == 3) and
+        not Match(scope_or_label_pattern, cleansed_line) and
+        not (clean_lines.raw_lines[linenum] != line and
+             Match(r'^\s*""', line))):
+    error(filename, linenum, 'whitespace/indent', 3,
+          'Weird number of spaces at line-start.  '
+          'Are you using a 2-space indent?')
+
+  # Check if the line is a header guard.
+  is_header_guard = False
+  if file_extension == 'h':
+    cppvar = GetHeaderGuardCPPVariable(filename)
+    if (line.startswith('#ifndef %s' % cppvar) or
+        line.startswith('#define %s' % cppvar) or
+        line.startswith('#endif  // %s' % cppvar)):
+      is_header_guard = True
+  # #include lines and header guards can be long, since there's no clean way to
+  # split them.
+  #
+  # URLs can be long too.  It's possible to split these, but it makes them
+  # harder to cut&paste.
+  #
+  # The "$Id:...$" comment may also get very long without it being the
+  # developers fault.
+  if (not line.startswith('#include') and not is_header_guard and
+      not Match(r'^\s*//.*http(s?)://\S*$', line) and
+      not Match(r'^// \$Id:.*#[0-9]+ \$$', line)):
+    line_width = GetLineWidth(line)
+    extended_length = int((_line_length * 1.25))
+    if line_width > extended_length:
+      error(filename, linenum, 'whitespace/line_length', 4,
+            'Lines should very rarely be longer than %i characters' %
+            extended_length)
+    elif line_width > _line_length:
+      error(filename, linenum, 'whitespace/line_length', 2,
+            'Lines should be <= %i characters long' % _line_length)
+
+  if (cleansed_line.count(';') > 1 and
+      # for loops are allowed two ;'s (and may run over two lines).
+      cleansed_line.find('for') == -1 and
+      (GetPreviousNonBlankLine(clean_lines, linenum)[0].find('for') == -1 or
+       GetPreviousNonBlankLine(clean_lines, linenum)[0].find(';') != -1) and
+      # It's ok to have many commands in a switch case that fits in 1 line
+      not ((cleansed_line.find('case ') != -1 or
+            cleansed_line.find('default:') != -1) and
+           cleansed_line.find('break;') != -1)):
+    error(filename, linenum, 'whitespace/newline', 0,
+          'More than one command on the same line')
+
+  # Some more style checks
+  CheckBraces(filename, clean_lines, linenum, error)
+  CheckTrailingSemicolon(filename, clean_lines, linenum, error)
+  CheckEmptyBlockBody(filename, clean_lines, linenum, error)
+  CheckAccess(filename, clean_lines, linenum, nesting_state, error)
+  CheckSpacing(filename, clean_lines, linenum, nesting_state, error)
+  CheckOperatorSpacing(filename, clean_lines, linenum, error)
+  CheckParenthesisSpacing(filename, clean_lines, linenum, error)
+  CheckCommaSpacing(filename, clean_lines, linenum, error)
+  CheckBracesSpacing(filename, clean_lines, linenum, error)
+  CheckSpacingForFunctionCall(filename, clean_lines, linenum, error)
+  CheckRValueReference(filename, clean_lines, linenum, nesting_state, error)
+  CheckCheck(filename, clean_lines, linenum, error)
+  CheckAltTokens(filename, clean_lines, linenum, error)
+  classinfo = nesting_state.InnermostClass()
+  if classinfo:
+    CheckSectionSpacing(filename, clean_lines, classinfo, linenum, error)
+
+
+_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.cc').group(0) == 'foo'
+#  _RE_FIRST_COMPONENT.match('foo-bar_baz.cc').group(0) == 'foo'
+#  _RE_FIRST_COMPONENT.match('foo_bar-baz.cc').group(0) == 'foo'
+_RE_FIRST_COMPONENT = re.compile(r'^[^-_.]+')
+
+
+def _DropCommonSuffixes(filename):
+  """Drops common suffixes like _test.cc or -inl.h from filename.
+
+  For example:
+    >>> _DropCommonSuffixes('foo/foo-inl.h')
+    'foo/foo'
+    >>> _DropCommonSuffixes('foo/bar/foo.cc')
+    'foo/bar/foo'
+    >>> _DropCommonSuffixes('foo/foo_internal.h')
+    'foo/foo'
+    >>> _DropCommonSuffixes('foo/foo_unusualinternal.h')
+    'foo/foo_unusualinternal'
+
+  Args:
+    filename: The input filename.
+
+  Returns:
+    The filename with the common suffix removed.
+  """
+  for suffix in ('test.cc', 'regtest.cc', 'unittest.cc',
+                 '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 _IsTestFilename(filename):
+  """Determines if the given filename has a suffix that identifies it as a test.
+
+  Args:
+    filename: The input filename.
+
+  Returns:
+    True if 'filename' looks like a test, False otherwise.
+  """
+  if (filename.endswith('_test.cc') or
+      filename.endswith('_unittest.cc') or
+      filename.endswith('_regtest.cc')):
+    return True
+  else:
+    return False
+
+
+def _ClassifyInclude(fileinfo, include, is_system):
+  """Figures out what kind of header 'include' is.
+
+  Args:
+    fileinfo: The current file cpplint is running over. A FileInfo instance.
+    include: The path to a #included file.
+    is_system: True if the #include used <> rather than "".
+
+  Returns:
+    One of the _XXX_HEADER constants.
+
+  For example:
+    >>> _ClassifyInclude(FileInfo('foo/foo.cc'), 'stdio.h', True)
+    _C_SYS_HEADER
+    >>> _ClassifyInclude(FileInfo('foo/foo.cc'), 'string', True)
+    _CPP_SYS_HEADER
+    >>> _ClassifyInclude(FileInfo('foo/foo.cc'), 'foo/foo.h', False)
+    _LIKELY_MY_HEADER
+    >>> _ClassifyInclude(FileInfo('foo/foo_unknown_extension.cc'),
+    ...                  'bar/foo_other_ext.h', False)
+    _POSSIBLE_MY_HEADER
+    >>> _ClassifyInclude(FileInfo('foo/foo.cc'), 'foo/bar.h', False)
+    _OTHER_HEADER
+  """
+  # This is a list of all standard c++ header files, except
+  # those already checked for above.
+  is_cpp_h = include in _CPP_HEADERS
+
+  if is_system:
+    if is_cpp_h:
+      return _CPP_SYS_HEADER
+    else:
+      return _C_SYS_HEADER
+
+  # If the target file and the include we're checking share a
+  # basename when we drop common extensions, and the include
+  # lives in . , then it's likely to be owned by the target file.
+  target_dir, target_base = (
+      os.path.split(_DropCommonSuffixes(fileinfo.RepositoryName())))
+  include_dir, include_base = os.path.split(_DropCommonSuffixes(include))
+  if target_base == include_base and (
+      include_dir == target_dir or
+      include_dir == os.path.normpath(target_dir + '/../public')):
+    return _LIKELY_MY_HEADER
+
+  # If the target and include share some initial basename
+  # component, it's possible the target is implementing the
+  # include, so it's allowed to be first, but we'll never
+  # complain if it's not there.
+  target_first_component = _RE_FIRST_COMPONENT.match(target_base)
+  include_first_component = _RE_FIRST_COMPONENT.match(include_base)
+  if (target_first_component and include_first_component and
+      target_first_component.group(0) ==
+      include_first_component.group(0)):
+    return _POSSIBLE_MY_HEADER
+
+  return _OTHER_HEADER
+
+
+
+def CheckIncludeLine(filename, clean_lines, linenum, 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.
+    clean_lines: A CleansedLines instance containing the file.
+    linenum: 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.
+  """
+  fileinfo = FileInfo(filename)
+  line = clean_lines.lines[linenum]
+
+  # "include" should use the new style "foo/bar.h" instead of just "bar.h"
+  # Only do this check if the included header follows google naming
+  # conventions.  If not, assume that it's a 3rd party API that
+  # requires special include conventions.
+  #
+  # We also make an exception for Lua headers, which follow google
+  # naming convention but not the include convention.
+  match = Match(r'#include\s*"([^/]+\.h)"', line)
+  if match and not _THIRD_PARTY_HEADERS_PATTERN.match(match.group(1)):
+    error(filename, linenum, 'build/include', 4,
+          'Include the directory when naming .h files')
+
+  # we shouldn't include a file more than once. actually, there are a
+  # handful of instances where doing so is okay, but in general it's
+  # not.
+  match = _RE_PATTERN_INCLUDE.search(line)
+  if match:
+    include = match.group(2)
+    is_system = (match.group(1) == '<')
+    duplicate_line = include_state.FindHeader(include)
+    if duplicate_line >= 0:
+      error(filename, linenum, 'build/include', 4,
+            '"%s" already included at %s:%s' %
+            (include, filename, duplicate_line))
+    elif (include.endswith('.cc') and
+          os.path.dirname(fileinfo.RepositoryName()) != os.path.dirname(include)):
+      error(filename, linenum, 'build/include', 4,
+            'Do not include .cc files from other packages')
+    elif not _THIRD_PARTY_HEADERS_PATTERN.match(include):
+      include_state.include_list[-1].append((include, linenum))
+
+      # We want to ensure that headers appear in the right order:
+      # 1) for foo.cc, foo.h  (preferred location)
+      # 2) c system files
+      # 3) cpp system files
+      # 4) for foo.cc, foo.h  (deprecated location)
+      # 5) other google headers
+      #
+      # We classify each include statement as one of those 5 types
+      # using a number of techniques. The include_state object keeps
+      # track of the highest type seen, and complains if we see a
+      # lower type after that.
+      error_message = include_state.CheckNextIncludeOrder(
+          _ClassifyInclude(fileinfo, include, is_system))
+      if error_message:
+        error(filename, linenum, 'build/include_order', 4,
+              '%s. Should be: %s.h, c system, c++ system, other.' %
+              (error_message, fileinfo.BaseName()))
+      canonical_include = include_state.CanonicalizeAlphabeticalOrder(include)
+      if not include_state.IsInAlphabeticalOrder(
+          clean_lines, linenum, canonical_include):
+        error(filename, linenum, 'build/include_alpha', 4,
+              'Include "%s" not in alphabetical order' % include)
+      include_state.SetLastHeader(canonical_include)
+
+
+
+def _GetTextInside(text, start_pattern):
+  r"""Retrieves all the text between matching open and close parentheses.
+
+  Given a string of lines and a regular expression string, retrieve all the text
+  following the expression and between opening punctuation symbols like
+  (, [, or {, and the matching close-punctuation symbol. This properly nested
+  occurrences of the punctuations, so for the text like
+    printf(a(), b(c()));
+  a call to _GetTextInside(text, r'printf\(') will return 'a(), b(c())'.
+  start_pattern must match string having an open punctuation symbol at the end.
+
+  Args:
+    text: The lines to extract text. Its comments and strings must be elided.
+           It can be single line and can span multiple lines.
+    start_pattern: The regexp string indicating where to start extracting
+                   the text.
+  Returns:
+    The extracted text.
+    None if either the opening string or ending punctuation could not be found.
+  """
+  # TODO(unknown): Audit cpplint.py to see what places could be profitably
+  # rewritten to use _GetTextInside (and use inferior regexp matching today).
+
+  # Give opening punctuations to get the matching close-punctuations.
+  matching_punctuation = {'(': ')', '{': '}', '[': ']'}
+  closing_punctuation = set(matching_punctuation.itervalues())
+
+  # Find the position to start extracting text.
+  match = re.search(start_pattern, text, re.M)
+  if not match:  # start_pattern not found in text.
+    return None
+  start_position = match.end(0)
+
+  assert start_position > 0, (
+      'start_pattern must ends with an opening punctuation.')
+  assert text[start_position - 1] in matching_punctuation, (
+      'start_pattern must ends with an opening punctuation.')
+  # Stack of closing punctuations we expect to have in text after position.
+  punctuation_stack = [matching_punctuation[text[start_position - 1]]]
+  position = start_position
+  while punctuation_stack and position < len(text):
+    if text[position] == punctuation_stack[-1]:
+      punctuation_stack.pop()
+    elif text[position] in closing_punctuation:
+      # A closing punctuation without matching opening punctuations.
+      return None
+    elif text[position] in matching_punctuation:
+      punctuation_stack.append(matching_punctuation[text[position]])
+    position += 1
+  if punctuation_stack:
+    # Opening punctuations left without matching close-punctuations.
+    return None
+  # punctuations match.
+  return text[start_position:position - 1]
+
+
+# Patterns for matching call-by-reference parameters.
+#
+# Supports nested templates up to 2 levels deep using this messy pattern:
+#   < (?: < (?: < [^<>]*
+#               >
+#           |   [^<>] )*
+#         >
+#     |   [^<>] )*
+#   >
+_RE_PATTERN_IDENT = r'[_a-zA-Z]\w*'  # =~ [[:alpha:]][[:alnum:]]*
+_RE_PATTERN_TYPE = (
+    r'(?:const\s+)?(?:typename\s+|class\s+|struct\s+|union\s+|enum\s+)?'
+    r'(?:\w|'
+    r'\s*<(?:<(?:<[^<>]*>|[^<>])*>|[^<>])*>|'
+    r'::)+')
+# A call-by-reference parameter ends with '& identifier'.
+_RE_PATTERN_REF_PARAM = re.compile(
+    r'(' + _RE_PATTERN_TYPE + r'(?:\s*(?:\bconst\b|[*]))*\s*'
+    r'&\s*' + _RE_PATTERN_IDENT + r')\s*(?:=[^,()]+)?[,)]')
+# A call-by-const-reference parameter either ends with 'const& identifier'
+# or looks like 'const type& identifier' when 'type' is atomic.
+_RE_PATTERN_CONST_REF_PARAM = (
+    r'(?:.*\s*\bconst\s*&\s*' + _RE_PATTERN_IDENT +
+    r'|const\s+' + _RE_PATTERN_TYPE + r'\s*&\s*' + _RE_PATTERN_IDENT + r')')
+
+
+def CheckLanguage(filename, clean_lines, linenum, file_extension,
+                  include_state, nesting_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.
+    linenum: 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.
+    nesting_state: A NestingState instance which maintains information about
+                   the current stack of nested blocks being parsed.
+    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[linenum]
+  if not line:
+    return
+
+  match = _RE_PATTERN_INCLUDE.search(line)
+  if match:
+    CheckIncludeLine(filename, clean_lines, linenum, include_state, error)
+    return
+
+  # Reset include state across preprocessor directives.  This is meant
+  # to silence warnings for conditional includes.
+  match = Match(r'^\s*#\s*(if|ifdef|ifndef|elif|else|endif)\b', line)
+  if match:
+    include_state.ResetSection(match.group(1))
+
+  # Make Windows paths like Unix.
+  fullname = os.path.abspath(filename).replace('\\', '/')
+  
+  # Perform other checks now that we are sure that this is not an include line
+  CheckCasts(filename, clean_lines, linenum, error)
+  CheckGlobalStatic(filename, clean_lines, linenum, error)
+  CheckPrintf(filename, clean_lines, linenum, error)
+
+  if file_extension == 'h':
+    # TODO(unknown): check that 1-arg constructors are explicit.
+    #                How to tell it's a constructor?
+    #                (handled in CheckForNonStandardConstructs for now)
+    # TODO(unknown): check that classes declare or disable copy/assign
+    #                (level 1 error)
+    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(filename, linenum, 'runtime/int', 4,
+            'Use "unsigned short" for ports, not "short"')
+  else:
+    match = Search(r'\b(short|long(?! +double)|long long)\b', line)
+    if match:
+      error(filename, linenum, 'runtime/int', 4,
+            'Use int16/int64/etc, rather than the C type %s' % match.group(1))
+
+  # Check if some verboten operator overloading is going on
+  # TODO(unknown): catch out-of-line unary operator&:
+  #   class X {};
+  #   int operator&(const X& x) { return 42; }  // unary operator&
+  # The trick is it's hard to tell apart from binary operator&:
+  #   class Y { int operator&(const Y& x) { return 23; } }; // binary operator&
+  if Search(r'\boperator\s*&\s*\(\s*\)', line):
+    error(filename, linenum, 'runtime/operator', 4,
+          'Unary operator& is dangerous.  Do not use it.')
+
+  # Check for suspicious usage of "if" like
+  # } if (a == b) {
+  if Search(r'\}\s*if\s*\(', line):
+    error(filename, linenum, '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())
+  # TODO(unknown): Catch the following case. Need to change the calling
+  # convention of the whole function to process multiple line to handle it.
+  #   printf(
+  #       boy_this_is_a_really_long_variable_that_cannot_fit_on_the_prev_line);
+  printf_args = _GetTextInside(line, r'(?i)\b(string)?printf\s*\(')
+  if printf_args:
+    match = Match(r'([\w.\->()]+)$', printf_args)
+    if match and match.group(1) != '__VA_ARGS__':
+      function_name = re.search(r'\b((?:string)?printf)\s*\(',
+                                line, re.I).group(1)
+      error(filename, linenum, 'runtime/printf', 4,
+            'Potential format string bug. Do %s("%%s", %s) instead.'
+            % (function_name, match.group(1)))
+
+  # Check for potential memset bugs like memset(buf, sizeof(buf), 0).
+  match = Search(r'memset\s*\(([^,]*),\s*([^,]*),\s*0\s*\)', line)
+  if match and not Match(r"^''|-?[0-9]+|0x[0-9A-Fa-f]$", match.group(2)):
+    error(filename, linenum, 'runtime/memset', 4,
+          'Did you mean "memset(%s, 0, %s)"?'
+          % (match.group(1), match.group(2)))
+
+  if Search(r'\busing namespace\b', line):
+    error(filename, linenum, 'build/namespaces', 5,
+          'Do not use namespace using-directives.  '
+          'Use using-declarations instead.')
+
+  # Detect variable-length arrays.
+  match = Match(r'\s*(.+::)?(\w+) [a-z]\w*\[(.+)];', line)
+  if (match and match.group(2) != 'return' and match.group(2) != 'delete' and
+      match.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|\+|\-|\*|\/|<<|>>]', match.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(filename, linenum, '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(filename, linenum, '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.')
+
+
+def CheckGlobalStatic(filename, clean_lines, linenum, error):
+  """Check for unsafe global or static objects.
+
+  Args:
+    filename: The name of the current file.
+    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.
+  """
+  line = clean_lines.elided[linenum]
+
+  # Match two lines at a time to support multiline declarations
+  if linenum + 1 < clean_lines.NumLines() and not Search(r'[;({]', line):
+    line += clean_lines.elided[linenum + 1].strip()
+
+  # 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.
+  match = Match(
+      r'((?:|static +)(?:|const +))string +([a-zA-Z0-9_:]+)\b(.*)',
+      line)
+
+  # Remove false positives:
+  # - String pointers (as opposed to values).
+  #    string *pointer
+  #    const string *pointer
+  #    string const *pointer
+  #    string *const pointer
+  #
+  # - Functions and template specializations.
+  #    string Function<Type>(...
+  #    string Class<Type>::Method(...
+  #
+  # - Operators.  These are matched separately because operator names
+  #   cross non-word boundaries, and trying to match both operators
+  #   and functions at the same time would decrease accuracy of
+  #   matching identifiers.
+  #    string Class::operator*()
+  if (match and
+      not Search(r'\bstring\b(\s+const)?\s*\*\s*(const\s+)?\w', line) and
+      not Search(r'\boperator\W', line) and
+      not Match(r'\s*(<.*>)?(::[a-zA-Z0-9_]+)*\s*\(([^"]|$)', match.group(3))):
+    error(filename, linenum, 'runtime/string', 4,
+          'For a static/global string constant, use a C style string instead: '
+          '"%schar %s[]".' %
+          (match.group(1), match.group(2)))
+
+  if Search(r'\b([A-Za-z0-9_]*_)\(\1\)', line):
+    error(filename, linenum, 'runtime/init', 4,
+          'You seem to be initializing a member variable with itself.')
+
+
+def CheckPrintf(filename, clean_lines, linenum, error):
+  """Check for printf related issues.
+
+  Args:
+    filename: The name of the current file.
+    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.
+  """
+  line = clean_lines.elided[linenum]
+
+  # When snprintf is used, the second argument shouldn't be a literal.
+  match = Search(r'snprintf\s*\(([^,]*),\s*([0-9]*)\s*,', line)
+  if match and match.group(2) != '0':
+    # If 2nd arg is zero, snprintf is used to calculate size.
+    error(filename, linenum, 'runtime/printf', 3,
+          'If you can, use sizeof(%s) instead of %s as the 2nd arg '
+          'to snprintf.' % (match.group(1), match.group(2)))
+
+  # Check if some verboten C functions are being used.
+  if Search(r'\bsprintf\s*\(', line):
+    error(filename, linenum, 'runtime/printf', 5,
+          'Never use sprintf. Use snprintf instead.')
+  match = Search(r'\b(strcpy|strcat)\s*\(', line)
+  if match:
+    error(filename, linenum, 'runtime/printf', 4,
+          'Almost always, snprintf is better than %s' % match.group(1))
+
+
+def IsDerivedFunction(clean_lines, linenum):
+  """Check if current line contains an inherited function.
+
+  Args:
+    clean_lines: A CleansedLines instance containing the file.
+    linenum: The number of the line to check.
+  Returns:
+    True if current line contains a function with "override"
+    virt-specifier.
+  """
+  # Scan back a few lines for start of current function
+  for i in xrange(linenum, max(-1, linenum - 10), -1):
+    match = Match(r'^([^()]*\w+)\(', clean_lines.elided[i])
+    if match:
+      # Look for "override" after the matching closing parenthesis
+      line, _, closing_paren = CloseExpression(
+          clean_lines, i, len(match.group(1)))
+      return (closing_paren >= 0 and
+              Search(r'\boverride\b', line[closing_paren:]))
+  return False
+
+
+def IsOutOfLineMethodDefinition(clean_lines, linenum):
+  """Check if current line contains an out-of-line method definition.
+
+  Args:
+    clean_lines: A CleansedLines instance containing the file.
+    linenum: The number of the line to check.
+  Returns:
+    True if current line contains an out-of-line method definition.
+  """
+  # Scan back a few lines for start of current function
+  for i in xrange(linenum, max(-1, linenum - 10), -1):
+    if Match(r'^([^()]*\w+)\(', clean_lines.elided[i]):
+      return Match(r'^[^()]*\w+::\w+\(', clean_lines.elided[i]) is not None
+  return False
+
+
+def IsInitializerList(clean_lines, linenum):
+  """Check if current line is inside constructor initializer list.
+
+  Args:
+    clean_lines: A CleansedLines instance containing the file.
+    linenum: The number of the line to check.
+  Returns:
+    True if current line appears to be inside constructor initializer
+    list, False otherwise.
+  """
+  for i in xrange(linenum, 1, -1):
+    line = clean_lines.elided[i]
+    if i == linenum:
+      remove_function_body = Match(r'^(.*)\{\s*$', line)
+      if remove_function_body:
+        line = remove_function_body.group(1)
+
+    if Search(r'\s:\s*\w+[({]', line):
+      # A lone colon tend to indicate the start of a constructor
+      # initializer list.  It could also be a ternary operator, which
+      # also tend to appear in constructor initializer lists as
+      # opposed to parameter lists.
+      return True
+    if Search(r'\}\s*,\s*$', line):
+      # A closing brace followed by a comma is probably the end of a
+      # brace-initialized member in constructor initializer list.
+      return True
+    if Search(r'[{};]\s*$', line):
+      # Found one of the following:
+      # - A closing brace or semicolon, probably the end of the previous
+      #   function.
+      # - An opening brace, probably the start of current class or namespace.
+      #
+      # Current line is probably not inside an initializer list since
+      # we saw one of those things without seeing the starting colon.
+      return False
+
+  # Got to the beginning of the file without seeing the start of
+  # constructor initializer list.
+  return False
+
+
+def CheckForNonConstReference(filename, clean_lines, linenum,
+                              nesting_state, error):
+  """Check for non-const references.
+
+  Separate from CheckLanguage since it scans backwards from current
+  line, instead of scanning forward.
+
+  Args:
+    filename: The name of the current file.
+    clean_lines: A CleansedLines instance containing the file.
+    linenum: The number of the line to check.
+    nesting_state: A NestingState instance which maintains information about
+                   the current stack of nested blocks being parsed.
+    error: The function to call with any errors found.
+  """
+  # Do nothing if there is no '&' on current line.
+  line = clean_lines.elided[linenum]
+  if '&' not in line:
+    return
+
+  # If a function is inherited, current function doesn't have much of
+  # a choice, so any non-const references should not be blamed on
+  # derived function.
+  if IsDerivedFunction(clean_lines, linenum):
+    return
+
+  # Don't warn on out-of-line method definitions, as we would warn on the
+  # in-line declaration, if it isn't marked with 'override'.
+  if IsOutOfLineMethodDefinition(clean_lines, linenum):
+    return
+
+  # Long type names may be broken across multiple lines, usually in one
+  # of these forms:
+  #   LongType
+  #       ::LongTypeContinued &identifier
+  #   LongType::
+  #       LongTypeContinued &identifier
+  #   LongType<
+  #       ...>::LongTypeContinued &identifier
+  #
+  # If we detected a type split across two lines, join the previous
+  # line to current line so that we can match const references
+  # accordingly.
+  #
+  # Note that this only scans back one line, since scanning back
+  # arbitrary number of lines would be expensive.  If you have a type
+  # that spans more than 2 lines, please use a typedef.
+  if linenum > 1:
+    previous = None
+    if Match(r'\s*::(?:[\w<>]|::)+\s*&\s*\S', line):
+      # previous_line\n + ::current_line
+      previous = Search(r'\b((?:const\s*)?(?:[\w<>]|::)+[\w<>])\s*$',
+                        clean_lines.elided[linenum - 1])
+    elif Match(r'\s*[a-zA-Z_]([\w<>]|::)+\s*&\s*\S', line):
+      # previous_line::\n + current_line
+      previous = Search(r'\b((?:const\s*)?(?:[\w<>]|::)+::)\s*$',
+                        clean_lines.elided[linenum - 1])
+    if previous:
+      line = previous.group(1) + line.lstrip()
+    else:
+      # Check for templated parameter that is split across multiple lines
+      endpos = line.rfind('>')
+      if endpos > -1:
+        (_, startline, startpos) = ReverseCloseExpression(
+            clean_lines, linenum, endpos)
+        if startpos > -1 and startline < linenum:
+          # Found the matching < on an earlier line, collect all
+          # pieces up to current line.
+          line = ''
+          for i in xrange(startline, linenum + 1):
+            line += clean_lines.elided[i].strip()
+
+  # Check for non-const references in function parameters.  A single '&' may
+  # found in the following places:
+  #   inside expression: binary & for bitwise AND
+  #   inside expression: unary & for taking the address of something
+  #   inside declarators: reference parameter
+  # We will exclude the first two cases by checking that we are not inside a
+  # function body, including one that was just introduced by a trailing '{'.
+  # TODO(unknown): Doesn't account for 'catch(Exception& e)' [rare].
+  if (nesting_state.previous_stack_top and
+      not (isinstance(nesting_state.previous_stack_top, _ClassInfo) or
+           isinstance(nesting_state.previous_stack_top, _NamespaceInfo))):
+    # Not at toplevel, not within a class, and not within a namespace
+    return
+
+  # Avoid initializer lists.  We only need to scan back from the
+  # current line for something that starts with ':'.
+  #
+  # We don't need to check the current line, since the '&' would
+  # appear inside the second set of parentheses on the current line as
+  # opposed to the first set.
+  if linenum > 0:
+    for i in xrange(linenum - 1, max(0, linenum - 10), -1):
+      previous_line = clean_lines.elided[i]
+      if not Search(r'[),]\s*$', previous_line):
+        break
+      if Match(r'^\s*:\s+\S', previous_line):
+        return
+
+  # Avoid preprocessors
+  if Search(r'\\\s*$', line):
+    return
+
+  # Avoid constructor initializer lists
+  if IsInitializerList(clean_lines, linenum):
+    return
+
+  # We allow non-const references in a few standard places, like functions
+  # called "swap()" or iostream operators like "<<" or ">>".  Do not check
+  # those function parameters.
+  #
+  # We also accept & in static_assert, which looks like a function but
+  # it's actually a declaration expression.
+  whitelisted_functions = (r'(?:[sS]wap(?:<\w:+>)?|'
+                           r'operator\s*[<>][<>]|'
+                           r'static_assert|COMPILE_ASSERT'
+                           r')\s*\(')
+  if Search(whitelisted_functions, line):
+    return
+  elif not Search(r'\S+\([^)]*$', line):
+    # Don't see a whitelisted function on this line.  Actually we
+    # didn't see any function name on this line, so this is likely a
+    # multi-line parameter list.  Try a bit harder to catch this case.
+    for i in xrange(2):
+      if (linenum > i and
+          Search(whitelisted_functions, clean_lines.elided[linenum - i - 1])):
+        return
+
+  decls = ReplaceAll(r'{[^}]*}', ' ', line)  # exclude function body
+  for parameter in re.findall(_RE_PATTERN_REF_PARAM, decls):
+    if not Match(_RE_PATTERN_CONST_REF_PARAM, parameter):
+      error(filename, linenum, 'runtime/references', 2,
+            'Is this a non-const reference? '
+            'If so, make const or use a pointer: ' +
+            ReplaceAll(' *<', '<', parameter))
+
+
+def CheckCasts(filename, clean_lines, linenum, error):
+  """Various cast related checks.
+
+  Args:
+    filename: The name of the current file.
+    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.
+  """
+  line = clean_lines.elided[linenum]
+
+  # 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.
+  match = Search(
+      r'(\bnew\s+|\S<\s*(?:const\s+)?)?\b'
+      r'(int|float|double|bool|char|int32|uint32|int64|uint64)'
+      r'(\([^)].*)', line)
+  expecting_function = ExpectingFunctionArgs(clean_lines, linenum)
+  if match and not expecting_function:
+    matched_type = match.group(2)
+
+    # matched_new_or_template is used to silence two false positives:
+    # - New operators
+    # - Template arguments with function types
+    #
+    # For template arguments, we match on types immediately following
+    # an opening bracket without any spaces.  This is a fast way to
+    # silence the common case where the function type is the first
+    # template argument.  False negative with less-than comparison is
+    # avoided because those operators are usually followed by a space.
+    #
+    #   function<double(double)>   // bracket + no space = false positive
+    #   value < double(42)         // bracket + space = true positive
+    matched_new_or_template = match.group(1)
+
+    # Avoid arrays by looking for brackets that come after the closing
+    # parenthesis.
+    if Match(r'\([^()]+\)\s*\[', match.group(3)):
+      return
+
+    # Other things to ignore:
+    # - Function pointers
+    # - Casts to pointer types
+    # - Placement new
+    # - Alias declarations
+    matched_funcptr = match.group(3)
+    if (matched_new_or_template is None and
+        not (matched_funcptr and
+             (Match(r'\((?:[^() ]+::\s*\*\s*)?[^() ]+\)\s*\(',
+                    matched_funcptr) or
+              matched_funcptr.startswith('(*)'))) and
+        not Match(r'\s*using\s+\S+\s*=\s*' + matched_type, line) and
+        not Search(r'new\(\S+\)\s*' + matched_type, line)):
+      error(filename, linenum, 'readability/casting', 4,
+            'Using deprecated casting style.  '
+            'Use static_cast<%s>(...) instead' %
+            matched_type)
+
+  if not expecting_function:
+    CheckCStyleCast(filename, clean_lines, linenum, '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".
+  #
+  # (char *) "foo" should always be a const_cast (reinterpret_cast won't
+  # compile).
+  if CheckCStyleCast(filename, clean_lines, linenum, 'const_cast',
+                     r'\((char\s?\*+\s?)\)\s*"', error):
+    pass
+  else:
+    # Check pointer casts for other than string constants
+    CheckCStyleCast(filename, clean_lines, linenum, '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.
+  #
+  # Some non-identifier character is required before the '&' for the
+  # expression to be recognized as a cast.  These are casts:
+  #   expression = &static_cast<int*>(temporary());
+  #   function(&(int*)(temporary()));
+  #
+  # This is not a cast:
+  #   reference_type&(int* function_param);
+  match = Search(
+      r'(?:[^\w]&\(([^)*][^)]*)\)[\w(])|'
+      r'(?:[^\w]&(static|dynamic|down|reinterpret)_cast\b)', line)
+  if match:
+    # Try a better error message when the & is bound to something
+    # dereferenced by the casted pointer, as opposed to the casted
+    # pointer itself.
+    parenthesis_error = False
+    match = Match(r'^(.*&(?:static|dynamic|down|reinterpret)_cast\b)<', line)
+    if match:
+      _, y1, x1 = CloseExpression(clean_lines, linenum, len(match.group(1)))
+      if x1 >= 0 and clean_lines.elided[y1][x1] == '(':
+        _, y2, x2 = CloseExpression(clean_lines, y1, x1)
+        if x2 >= 0:
+          extended_line = clean_lines.elided[y2][x2:]
+          if y2 < clean_lines.NumLines() - 1:
+            extended_line += clean_lines.elided[y2 + 1]
+          if Match(r'\s*(?:->|\[)', extended_line):
+            parenthesis_error = True
+
+    if parenthesis_error:
+      error(filename, linenum, 'readability/casting', 4,
+            ('Are you taking an address of something dereferenced '
+             'from a cast?  Wrapping the dereferenced expression in '
+             'parentheses will make the binding more obvious'))
+    else:
+      error(filename, linenum, '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'))
+
+
+def CheckCStyleCast(filename, clean_lines, linenum, cast_type, pattern, error):
+  """Checks for a C-style cast by looking for the pattern.
+
+  Args:
+    filename: The name of the current file.
+    clean_lines: A CleansedLines instance containing the file.
+    linenum: The number of the line to check.
+    cast_type: The string for the C++ cast to recommend.  This is either
+      reinterpret_cast, static_cast, or const_cast, depending.
+    pattern: The regular expression used to find C-style casts.
+    error: The function to call with any errors found.
+
+  Returns:
+    True if an error was emitted.
+    False otherwise.
+  """
+  line = clean_lines.elided[linenum]
+  match = Search(pattern, line)
+  if not match:
+    return False
+
+  # Exclude lines with keywords that tend to look like casts
+  context = line[0:match.start(1) - 1]
+  if Match(r'.*\b(?:sizeof|alignof|alignas|[_A-Z][_A-Z0-9]*)\s*$', context):
+    return False
+
+  # Try expanding current context to see if we one level of
+  # parentheses inside a macro.
+  if linenum > 0:
+    for i in xrange(linenum - 1, max(0, linenum - 5), -1):
+      context = clean_lines.elided[i] + context
+  if Match(r'.*\b[_A-Z][_A-Z0-9]*\s*\((?:\([^()]*\)|[^()])*$', context):
+    return False
+
+  # operator++(int) and operator--(int)
+  if context.endswith(' operator++') or context.endswith(' operator--'):
+    return False
+
+  # A single unnamed argument for a function tends to look like old
+  # style cast.  If we see those, don't issue warnings for deprecated
+  # casts, instead issue warnings for unnamed arguments where
+  # appropriate.
+  #
+  # These are things that we want warnings for, since the style guide
+  # explicitly require all parameters to be named:
+  #   Function(int);
+  #   Function(int) {
+  #   ConstMember(int) const;
+  #   ConstMember(int) const {
+  #   ExceptionMember(int) throw (...);
+  #   ExceptionMember(int) throw (...) {
+  #   PureVirtual(int) = 0;
+  #   [](int) -> bool {
+  #
+  # These are functions of some sort, where the compiler would be fine
+  # if they had named parameters, but people often omit those
+  # identifiers to reduce clutter:
+  #   (FunctionPointer)(int);
+  #   (FunctionPointer)(int) = value;
+  #   Function((function_pointer_arg)(int))
+  #   Function((function_pointer_arg)(int), int param)
+  #   <TemplateArgument(int)>;
+  #   <(FunctionPointerTemplateArgument)(int)>;
+  remainder = line[match.end(0):]
+  if Match(r'^\s*(?:;|const\b|throw\b|final\b|override\b|[=>{),]|->)',
+           remainder):
+    # Looks like an unnamed parameter.
+
+    # Don't warn on any kind of template arguments.
+    if Match(r'^\s*>', remainder):
+      return False
+
+    # Don't warn on assignments to function pointers, but keep warnings for
+    # unnamed parameters to pure virtual functions.  Note that this pattern
+    # will also pass on assignments of "0" to function pointers, but the
+    # preferred values for those would be "nullptr" or "NULL".
+    matched_zero = Match(r'^\s=\s*(\S+)\s*;', remainder)
+    if matched_zero and matched_zero.group(1) != '0':
+      return False
+
+    # Don't warn on function pointer declarations.  For this we need
+    # to check what came before the "(type)" string.
+    if Match(r'.*\)\s*$', line[0:match.start(0)]):
+      return False
+
+    # Don't warn if the parameter is named with block comments, e.g.:
+    #  Function(int /*unused_param*/);
+    raw_line = clean_lines.raw_lines[linenum]
+    if '/*' in raw_line:
+      return False
+
+    # Passed all filters, issue warning here.
+    error(filename, linenum, 'readability/function', 3,
+          'All parameters should be named in a function')
+    return True
+
+  # At this point, all that should be left is actual casts.
+  error(filename, linenum, 'readability/casting', 4,
+        'Using C-style cast.  Use %s<%s>(...) instead' %
+        (cast_type, match.group(1)))
+
+  return True
+
+
+def ExpectingFunctionArgs(clean_lines, linenum):
+  """Checks whether where function type arguments are expected.
+
+  Args:
+    clean_lines: A CleansedLines instance containing the file.
+    linenum: The number of the line to check.
+
+  Returns:
+    True if the line at 'linenum' is inside something that expects arguments
+    of function types.
+  """
+  line = clean_lines.elided[linenum]
+  return (Match(r'^\s*MOCK_(CONST_)?METHOD\d+(_T)?\(', line) or
+          (linenum >= 2 and
+           (Match(r'^\s*MOCK_(?:CONST_)?METHOD\d+(?:_T)?\((?:\S+,)?\s*$',
+                  clean_lines.elided[linenum - 1]) or
+            Match(r'^\s*MOCK_(?:CONST_)?METHOD\d+(?:_T)?\(\s*$',
+                  clean_lines.elided[linenum - 2]) or
+            Search(r'\bstd::m?function\s*\<\s*$',
+                   clean_lines.elided[linenum - 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',)),
+    ('<tuple>', ('tuple',)),
+    ('<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',)),
+    )
+
+_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 FilesBelongToSameModule(filename_cc, 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.cc, foo_test.cc and foo_unittest.cc 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_cc contains a longer path than the filename_h, for example,
+  '/absolute/path/to/base/sysinfo.cc', 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.cc 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_cc: is the path for the .cc file
+    filename_h: is the path for the header path
+
+  Returns:
+    Tuple with a bool and a string:
+    bool: True if filename_cc and filename_h belong to the same module.
+    string: the additional prefix needed to open the header file.
+  """
+
+  if not filename_cc.endswith('.cc'):
+    return (False, '')
+  filename_cc = filename_cc[:-len('.cc')]
+  if filename_cc.endswith('_unittest'):
+    filename_cc = filename_cc[:-len('_unittest')]
+  elif filename_cc.endswith('_test'):
+    filename_cc = filename_cc[:-len('_test')]
+  filename_cc = filename_cc.replace('/public/', '/')
+  filename_cc = filename_cc.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_cc.endswith(filename_h)
+  common_path = ''
+  if files_belong_to_same_module:
+    common_path = filename_cc[:-len(filename_h)]
+  return files_belong_to_same_module, common_path
+
+
+def UpdateIncludeState(filename, include_dict, io=codecs):
+  """Fill up the include_dict with new includes found from the file.
+
+  Args:
+    filename: the name of the header to read.
+    include_dict: a dictionary 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 successfully added. False otherwise.
+  """
+  headerfile = None
+  try:
+    headerfile = io.open(filename, 'r', 'utf8', 'replace')
+  except IOError:
+    return False
+  linenum = 0
+  for line in headerfile:
+    linenum += 1
+    clean_line = CleanseComments(line)
+    match = _RE_PATTERN_INCLUDE.search(clean_line)
+    if match:
+      include = match.group(2)
+      include_dict.setdefault(include, linenum)
+  return True
+
+
+def CheckForIncludeWhatYouUse(filename, clean_lines, include_state, error,
+                              io=codecs):
+  """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.
+    io: The IO factory to use to read the header file. Provided for unittest
+        injection.
+  """
+  required = {}  # A map of header name to linenumber and the template entity.
+                 # Example of required: { '<functional>': (1219, 'less<>') }
+
+  for linenum in xrange(clean_lines.NumLines()):
+    line = clean_lines.elided[linenum]
+    if not line or line[0] == '#':
+      continue
+
+    # String is special -- it is a non-templatized type in STL.
+    matched = _RE_PATTERN_STRING.search(line)
+    if matched:
+      # Don't warn about strings in non-STL namespaces:
+      # (We check only the first match per line; good enough.)
+      prefix = line[:matched.start()]
+      if prefix.endswith('std::') or not prefix.endswith('::'):
+        required['<string>'] = (linenum, 'string')
+
+    for pattern, template, header in _re_pattern_algorithm_header:
+      if pattern.search(line):
+        required[header] = (linenum, 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] = (linenum, template)
+
+  # The policy is that if you #include something in foo.h you don't need to
+  # include it again in foo.cc. Here, we will look at possible includes.
+  # Let's flatten the include_state include_list and copy it into a dictionary.
+  include_dict = dict([item for sublist in include_state.include_list
+                       for item in sublist])
+
+  # Did we find the header for this file (if any) and successfully load it?
+  header_found = False
+
+  # Use the absolute path so that matching works properly.
+  abs_filename = FileInfo(filename).FullName()
+
+  # For Emacs's flymake.
+  # If cpplint is invoked from Emacs's flymake, a temporary file is generated
+  # by flymake and that file name might end with '_flymake.cc'. 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.cc', we should search for 'foo.h'
+  # instead of 'foo_flymake.h'
+  abs_filename = re.sub(r'_flymake\.cc$', '.cc', abs_filename)
+
+  # include_dict is modified during iteration, so we iterate over a copy of
+  # the keys.
+  header_keys = include_dict.keys()
+  for header in header_keys:
+    (same_module, common_path) = FilesBelongToSameModule(abs_filename, header)
+    fullpath = common_path + header
+    if same_module and UpdateIncludeState(fullpath, include_dict, io):
+      header_found = True
+
+  # If we can't find the header file for a .cc, 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.
+  # TODO(unknown): 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('.cc') 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 required_header_unstripped.strip('<>"') not in include_dict:
+      error(filename, required[required_header_unstripped][0],
+            'build/include_what_you_use', 4,
+            'Add #include ' + required_header_unstripped + ' for ' + template)
+
+
+_RE_PATTERN_EXPLICIT_MAKEPAIR = re.compile(r'\bmake_pair\s*<')
+
+
+def CheckMakePairUsesDeduction(filename, clean_lines, linenum, error):
+  """Check that make_pair's template arguments are deduced.
+
+  G++ 4.6 in C++11 mode fails badly if make_pair's template arguments are
+  specified explicitly, and such use isn't intended in any case.
+
+  Args:
+    filename: The name of the current file.
+    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.
+  """
+  line = clean_lines.elided[linenum]
+  match = _RE_PATTERN_EXPLICIT_MAKEPAIR.search(line)
+  if match:
+    error(filename, linenum, 'build/explicit_make_pair',
+          4,  # 4 = high confidence
+          'For C++11-compatibility, omit template arguments from make_pair'
+          ' OR use pair directly OR if appropriate, construct a pair directly')
+
+
+def CheckDefaultLambdaCaptures(filename, clean_lines, linenum, error):
+  """Check that default lambda captures are not used.
+
+  Args:
+    filename: The name of the current file.
+    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.
+  """
+  line = clean_lines.elided[linenum]
+
+  # A lambda introducer specifies a default capture if it starts with "[="
+  # or if it starts with "[&" _not_ followed by an identifier.
+  match = Match(r'^(.*)\[\s*(?:=|&[^\w])', line)
+  if match:
+    # Found a potential error, check what comes after the lambda-introducer.
+    # If it's not open parenthesis (for lambda-declarator) or open brace
+    # (for compound-statement), it's not a lambda.
+    line, _, pos = CloseExpression(clean_lines, linenum, len(match.group(1)))
+    if pos >= 0 and Match(r'^\s*[{(]', line[pos:]):
+      error(filename, linenum, 'build/c++11',
+            4,  # 4 = high confidence
+            'Default lambda captures are an unapproved C++ feature.')
+
+
+def CheckRedundantVirtual(filename, clean_lines, linenum, error):
+  """Check if line contains a redundant "virtual" function-specifier.
+
+  Args:
+    filename: The name of the current file.
+    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_col = -1
+  end_line = -1
+  start_col = len(virtual.group(2))
+  for start_line in xrange(linenum, min(linenum + 3, clean_lines.NumLines())):
+    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_line, end_col) = CloseExpression(
+          clean_lines, start_line, start_col + len(parameter_list.group(1)))
+      break
+    start_col = 0
+
+  if end_col < 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_line, min(end_line + 3, clean_lines.NumLines())):
+    line = clean_lines.elided[i][end_col:]
+    match = Search(r'\b(override|final)\b', line)
+    if match:
+      error(filename, linenum, 'readability/inheritance', 4,
+            ('"virtual" is redundant since function is '
+             'already declared as "%s"' % match.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 CheckRedundantOverrideOrFinal(filename, clean_lines, linenum, error):
+  """Check if line contains a redundant "override" or "final" virt-specifier.
+
+  Args:
+    filename: The name of the current file.
+    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(filename, linenum, 'readability/inheritance', 4,
+          ('"override" is redundant since function is '
+           'already declared as "final"'))
+
+
+
+
+# Returns true if we are at a new block, and it is directly
+# inside of a namespace.
+def IsBlockInNameSpace(nesting_state, is_forward_declaration):
+  """Checks that the new block is directly in a namespace.
+
+  Args:
+    nesting_state: The _NestingState object that contains info about our state.
+    is_forward_declaration: If the class is a forward declared class.
+  Returns:
+    Whether or not the new block is directly in a namespace.
+  """
+  if is_forward_declaration:
+    if len(nesting_state.stack) >= 1 and (
+        isinstance(nesting_state.stack[-1], _NamespaceInfo)):
+      return True
+    else:
+      return False
+
+  return (len(nesting_state.stack) > 1 and
+          nesting_state.stack[-1].check_namespace_indentation and
+          isinstance(nesting_state.stack[-2], _NamespaceInfo))
+
+
+def ShouldCheckNamespaceIndentation(nesting_state, is_namespace_indent_item,
+                                    raw_lines_no_comments, linenum):
+  """This method determines if we should apply our namespace indentation check.
+
+  Args:
+    nesting_state: The current nesting state.
+    is_namespace_indent_item: If we just put a new class on the stack, True.
+      If the top of the stack is not a class, or we did not recently
+      add the class, False.
+    raw_lines_no_comments: The lines without the comments.
+    linenum: The current line number we are processing.
+
+  Returns:
+    True if we should apply our namespace indentation check. Currently, it
+    only works for classes and namespaces inside of a namespace.
+  """
+
+  is_forward_declaration = IsForwardClassDeclaration(raw_lines_no_comments,
+                                                     linenum)
+
+  if not (is_namespace_indent_item or is_forward_declaration):
+    return False
+
+  # If we are in a macro, we do not want to check the namespace indentation.
+  if IsMacroDefinition(raw_lines_no_comments, linenum):
+    return False
+
+  return IsBlockInNameSpace(nesting_state, is_forward_declaration)
+
+
+# Call this method if the line is directly inside of a namespace.
+# If the line above is blank (excluding comments) or the start of
+# an inner namespace, it cannot be indented.
+def CheckItemIndentationInNamespace(filename, raw_lines_no_comments, linenum,
+                                    error):
+  line = raw_lines_no_comments[linenum]
+  if Match(r'^\s+', line):
+    error(filename, linenum, 'runtime/indentation_namespace', 4,
+          'Do not indent within a namespace')
+
+
+def ProcessLine(filename, file_extension, clean_lines, line,
+                include_state, function_state, nesting_state, error,
+                extra_check_functions=[]):
+  """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.
+    nesting_state: A NestingState instance which maintains information about
+                   the current stack of nested blocks being parsed.
+    error: A callable to which errors are reported, which takes 4 arguments:
+           filename, line number, error level, and message
+    extra_check_functions: An array of additional check functions that will be
+                           run on each source line. Each function takes 4
+                           arguments: filename, clean_lines, line, error
+  """
+  raw_lines = clean_lines.raw_lines
+  ParseNolintSuppressions(filename, raw_lines[line], line, error)
+  nesting_state.Update(filename, clean_lines, line, error)
+  CheckForNamespaceIndentation(filename, nesting_state, clean_lines, line,
+                               error)
+  if nesting_state.InAsmBlock(): return
+  CheckForFunctionLengths(filename, clean_lines, line, function_state, error)
+  CheckForMultilineCommentsAndStrings(filename, clean_lines, line, error)
+  CheckStyle(filename, clean_lines, line, file_extension, nesting_state, error)
+  CheckLanguage(filename, clean_lines, line, file_extension, include_state,
+                nesting_state, error)
+  CheckForNonConstReference(filename, clean_lines, line, nesting_state, error)
+  CheckForNonStandardConstructs(filename, clean_lines, line,
+                                nesting_state, error)
+  CheckVlogArguments(filename, clean_lines, line, error)
+  CheckPosixThreading(filename, clean_lines, line, error)
+  CheckInvalidIncrement(filename, clean_lines, line, error)
+  CheckMakePairUsesDeduction(filename, clean_lines, line, error)
+  CheckDefaultLambdaCaptures(filename, clean_lines, line, error)
+  CheckRedundantVirtual(filename, clean_lines, line, error)
+  CheckRedundantOverrideOrFinal(filename, clean_lines, line, error)
+  for check_fn in extra_check_functions:
+    check_fn(filename, clean_lines, line, error)
+
+def FlagCxx11Features(filename, clean_lines, linenum, error):
+  """Flag those c++11 features that we only allow in certain places.
+
+  Args:
+    filename: The name of the current file.
+    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.
+  """
+  line = clean_lines.elided[linenum]
+
+  # Flag unapproved C++11 headers.
+  include = Match(r'\s*#\s*include\s+[<"]([^<"]+)[">]', line)
+  if include and include.group(1) in ('cfenv',
+                                      'condition_variable',
+                                      'fenv.h',
+                                      'future',
+                                      'mutex',
+                                      'thread',
+                                      'chrono',
+                                      'ratio',
+                                      'regex',
+                                      'system_error',
+                                     ):
+    error(filename, linenum, 'build/c++11', 5,
+          ('<%s> is an unapproved C++11 header.') % include.group(1))
+
+  # The only place where we need to worry about C++11 keywords and library
+  # features in preprocessor directives is in macro definitions.
+  if Match(r'\s*#', line) and not Match(r'\s*#\s*define\b', line): return
+
+  # These are classes and free functions.  The classes are always
+  # mentioned as std::*, but we only catch the free functions if
+  # they're not found by ADL.  They're alphabetical by header.
+  for top_name in (
+      # type_traits
+      'alignment_of',
+      'aligned_union',
+      ):
+    if Search(r'\bstd::%s\b' % top_name, line):
+      error(filename, linenum, 'build/c++11', 5,
+            ('std::%s is an unapproved C++11 class or function.  Send c-style '
+             'an example of where it would make your code more readable, and '
+             'they may let you use it.') % top_name)
+
+
+def ProcessFileData(filename, file_extension, lines, error,
+                    extra_check_functions=[]):
+  """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:
+           filename, line number, error level, and message
+    extra_check_functions: An array of additional check functions that will be
+                           run on each source line. Each function takes 4
+                           arguments: filename, clean_lines, line, error
+  """
+  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()
+  nesting_state = NestingState()
+
+  ResetNolintSuppressions()
+
+  CheckForCopyright(filename, lines, error)
+
+  RemoveMultiLineComments(filename, lines, error)
+  clean_lines = CleansedLines(lines)
+
+  if file_extension == 'h':
+    CheckForHeaderGuard(filename, clean_lines, error)
+
+  for line in xrange(clean_lines.NumLines()):
+    ProcessLine(filename, file_extension, clean_lines, line,
+                include_state, function_state, nesting_state, error,
+                extra_check_functions)
+    FlagCxx11Features(filename, clean_lines, line, error)
+  nesting_state.CheckCompletedBlocks(filename, error)
+
+  CheckForIncludeWhatYouUse(filename, clean_lines, include_state, error)
+  
+  # Check that the .cc file has included its header if it exists.
+  if file_extension == 'cc':
+    CheckHeaderFileIncluded(filename, include_state, error)
+
+  # We check here rather than inside ProcessLine so that we see raw
+  # lines rather than "cleaned" lines.
+  CheckForBadCharacters(filename, lines, error)
+
+  CheckForNewlineAtEOF(filename, lines, error)
+
+def ProcessConfigOverrides(filename):
+  """ Loads the configuration files and processes the config overrides.
+
+  Args:
+    filename: The name of the file being processed by the linter.
+
+  Returns:
+    False if the current |filename| should not be processed further.
+  """
+
+  abs_filename = os.path.abspath(filename)
+  cfg_filters = []
+  keep_looking = True
+  while keep_looking:
+    abs_path, base_name = os.path.split(abs_filename)
+    if not base_name:
+      break  # Reached the root directory.
+
+    cfg_file = os.path.join(abs_path, "CPPLINT.cfg")
+    abs_filename = abs_path
+    if not os.path.isfile(cfg_file):
+      continue
+
+    try:
+      with open(cfg_file) as file_handle:
+        for line in file_handle:
+          line, _, _ = line.partition('#')  # Remove comments.
+          if not line.strip():
+            continue
+
+          name, _, val = line.partition('=')
+          name = name.strip()
+          val = val.strip()
+          if name == 'set noparent':
+            keep_looking = False
+          elif name == 'filter':
+            cfg_filters.append(val)
+          elif name == 'exclude_files':
+            # When matching exclude_files pattern, use the base_name of
+            # the current file name or the directory name we are processing.
+            # For example, if we are checking for lint errors in /foo/bar/baz.cc
+            # and we found the .cfg file at /foo/CPPLINT.cfg, then the config
+            # file's "exclude_files" filter is meant to be checked against "bar"
+            # and not "baz" nor "bar/baz.cc".
+            if base_name:
+              pattern = re.compile(val)
+              if pattern.match(base_name):
+                sys.stderr.write('Ignoring "%s": file excluded by "%s". '
+                                 'File path component "%s" matches '
+                                 'pattern "%s"\n' %
+                                 (filename, cfg_file, base_name, val))
+                return False
+          elif name == 'linelength':
+            global _line_length
+            try:
+                _line_length = int(val)
+            except ValueError:
+                sys.stderr.write('Line length must be numeric.')
+          else:
+            sys.stderr.write(
+                'Invalid configuration option (%s) in file %s\n' %
+                (name, cfg_file))
+
+    except IOError:
+      sys.stderr.write(
+          "Skipping config file '%s': Can't open for reading\n" % cfg_file)
+      keep_looking = False
+
+  # Apply all the accumulated filters in reverse order (top-level directory
+  # config options having the least priority).
+  for filter in reversed(cfg_filters):
+     _AddFilters(filter)
+
+  return True
+
+
+def ProcessFile(filename, vlevel, extra_check_functions=[]):
+  """Does google-lint on a single file.
+
+  Args:
+    filename: The name of the file to parse.
+
+    vlevel: The level of errors to report.  Every error of confidence
+    >= verbose_level will be reported.  0 is a good default.
+
+    extra_check_functions: An array of additional check functions that will be
+                           run on each source line. Each function takes 4
+                           arguments: filename, clean_lines, line, error
+  """
+
+  _SetVerboseLevel(vlevel)
+  _BackupFilters()
+
+  if not ProcessConfigOverrides(filename):
+    _RestoreFilters()
+    return
+
+  lf_lines = []
+  crlf_lines = []
+  try:
+    # Support the UNIX convention of using "-" for stdin.  Note that
+    # we are not opening the file with universal newline support
+    # (which codecs doesn't support anyway), so the resulting lines do
+    # contain trailing '\r' characters if we are reading a file that
+    # has CRLF endings.
+    # If after the split a trailing '\r' is present, it is removed
+    # below.
+    if filename == '-':
+      lines = codecs.StreamReaderWriter(sys.stdin,
+                                        codecs.getreader('utf8'),
+                                        codecs.getwriter('utf8'),
+                                        'replace').read().split('\n')
+    else:
+      lines = codecs.open(filename, 'r', 'utf8', 'replace').read().split('\n')
+
+    # Remove trailing '\r'.
+    # The -1 accounts for the extra trailing blank line we get from split()
+    for linenum in range(len(lines) - 1):
+      if lines[linenum].endswith('\r'):
+        lines[linenum] = lines[linenum].rstrip('\r')
+        crlf_lines.append(linenum + 1)
+      else:
+        lf_lines.append(linenum + 1)
+
+  except IOError:
+    sys.stderr.write(
+        "Skipping input '%s': Can't open for reading\n" % filename)
+    _RestoreFilters()
+    return
+
+  # Note, if no dot is found, this will give the entire filename as the ext.
+  file_extension = filename[filename.rfind('.') + 1:]
+
+  # When reading from stdin, the extension is unknown, so no cpplint tests
+  # should rely on the extension.
+  if filename != '-' and file_extension not in _valid_extensions:
+    sys.stderr.write('Ignoring %s; not a valid file name '
+                     '(%s)\n' % (filename, ', '.join(_valid_extensions)))
+  else:
+    ProcessFileData(filename, file_extension, lines, Error,
+                    extra_check_functions)
+
+    # If end-of-line sequences are a mix of LF and CR-LF, issue
+    # warnings on the lines with CR.
+    #
+    # Don't issue any warnings if all lines are uniformly LF or CR-LF,
+    # since critique can handle these just fine, and the style guide
+    # doesn't dictate a particular end of line sequence.
+    #
+    # We can't depend on os.linesep to determine what the desired
+    # end-of-line sequence should be, since that will return the
+    # server-side end-of-line sequence.
+    if lf_lines and crlf_lines:
+      # Warn on every line with CR.  An alternative approach might be to
+      # check whether the file is mostly CRLF or just LF, and warn on the
+      # minority, we bias toward LF here since most tools prefer LF.
+      for linenum in crlf_lines:
+        Error(filename, linenum, 'whitespace/newline', 1,
+              'Unexpected \\r (^M) found; better to use only \\n')
+
+  sys.stderr.write('Done processing %s\n' % filename)
+  _RestoreFilters()
+
+
+def PrintUsage(message):
+  """Prints a brief usage string and exits, optionally with an error message.
+
+  Args:
+    message: The optional error message.
+  """
+  sys.stderr.write(_USAGE)
+  if message:
+    sys.exit('\nFATAL ERROR: ' + message)
+  else:
+    sys.exit(1)
+
+
+def PrintCategories():
+  """Prints a list of all the error-categories used by error messages.
+
+  These are the categories used to filter messages via --filter.
+  """
+  sys.stderr.write(''.join('  %s\n' % cat for cat in _ERROR_CATEGORIES))
+  sys.exit(0)
+
+
+def ParseArguments(args):
+  """Parses the command line arguments.
+
+  This may set the output format and verbosity level as side-effects.
+
+  Args:
+    args: The command line arguments:
+
+  Returns:
+    The list of filenames to lint.
+  """
+  try:
+    (opts, filenames) = getopt.getopt(args, '', ['help', 'output=', 'verbose=',
+                                                 'counting=',
+                                                 'filter=',
+                                                 'root=',
+                                                 'linelength=',
+                                                 'extensions='])
+  except getopt.GetoptError:
+    PrintUsage('Invalid arguments.')
+
+  verbosity = _VerboseLevel()
+  output_format = _OutputFormat()
+  filters = ''
+  counting_style = ''
+
+  for (opt, val) in opts:
+    if opt == '--help':
+      PrintUsage(None)
+    elif opt == '--output':
+      if val not in ('emacs', 'vs7', 'eclipse'):
+        PrintUsage('The only allowed output formats are emacs, vs7 and eclipse.')
+      output_format = val
+    elif opt == '--verbose':
+      verbosity = int(val)
+    elif opt == '--filter':
+      filters = val
+      if not filters:
+        PrintCategories()
+    elif opt == '--counting':
+      if val not in ('total', 'toplevel', 'detailed'):
+        PrintUsage('Valid counting options are total, toplevel, and detailed')
+      counting_style = val
+    elif opt == '--root':
+      global _root
+      _root = val
+    elif opt == '--linelength':
+      global _line_length
+      try:
+          _line_length = int(val)
+      except ValueError:
+          PrintUsage('Line length must be digits.')
+    elif opt == '--extensions':
+      global _valid_extensions
+      try:
+          _valid_extensions = set(val.split(','))
+      except ValueError:
+          PrintUsage('Extensions must be comma seperated list.')
+
+  if not filenames:
+    PrintUsage('No files were specified.')
+
+  _SetOutputFormat(output_format)
+  _SetVerboseLevel(verbosity)
+  _SetFilters(filters)
+  _SetCountingStyle(counting_style)
+
+  return filenames
+
+
+def main():
+  filenames = ParseArguments(sys.argv[1:])
+
+  # Change stderr to write with replacement characters so we don't die
+  # if we try to print something containing non-ASCII characters.
+  sys.stderr = codecs.StreamReaderWriter(sys.stderr,
+                                         codecs.getreader('utf8'),
+                                         codecs.getwriter('utf8'),
+                                         'replace')
+
+  _cpplint_state.ResetErrorCounts()
+  for filename in filenames:
+    ProcessFile(filename, _cpplint_state.verbose_level)
+  _cpplint_state.PrintErrorCounts()
+
+  sys.exit(_cpplint_state.error_count > 0)
+
+
+if __name__ == '__main__':
+  main()