[content/test/gpu] Run pylint check of gpu tests in unittest instead of PRESUBMIT

third_party/pylint/pylint/checkers/format.py

Index: third_party/pylint/pylint/checkers/format.py
diff --git a/third_party/pylint/pylint/checkers/format.py b/third_party/pylint/pylint/checkers/format.py
new file mode 100644
index 0000000000000000000000000000000000000000..94a9e8eb8d038e2eacfc3e7287da38036c0d6bf3
--- /dev/null
+++ b/third_party/pylint/pylint/checkers/format.py
@@ -0,0 +1,964 @@
+# Copyright (c) 2003-2013 LOGILAB S.A. (Paris, FRANCE).
+#
+# This program is free software; you can redistribute it and/or modify it under
+# the terms of the GNU General Public License as published by the Free Software
+# Foundation; either version 2 of the License, or (at your option) any later
+# version.
+#
+# This program is distributed in the hope that it will be useful, but WITHOUT
+# ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
+# FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License along with
+# this program; if not, write to the Free Software Foundation, Inc.,
+# 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
+"""Python code format's checker.
+
+By default try to follow Guido's style guide :
+
+http://www.python.org/doc/essays/styleguide.html
+
+Some parts of the process_token method is based from The Tab Nanny std module.
+"""
+
+import keyword
+import sys
+import tokenize
+from functools import reduce # pylint: disable=redefined-builtin
+
+import six
+from six.moves import zip, map, filter # pylint: disable=redefined-builtin
+
+from astroid import nodes
+
+from pylint.interfaces import ITokenChecker, IAstroidChecker, IRawChecker
+from pylint.checkers import BaseTokenChecker
+from pylint.checkers.utils import check_messages
+from pylint.utils import WarningScope, OPTION_RGX
+
+_CONTINUATION_BLOCK_OPENERS = ['elif', 'except', 'for', 'if', 'while', 'def', 'class']
+_KEYWORD_TOKENS = ['assert', 'del', 'elif', 'except', 'for', 'if', 'in', 'not',
+                   'raise', 'return', 'while', 'yield']
+if sys.version_info < (3, 0):
+    _KEYWORD_TOKENS.append('print')
+
+_SPACED_OPERATORS = ['==', '<', '>', '!=', '<>', '<=', '>=',
+                     '+=', '-=', '*=', '**=', '/=', '//=', '&=', '|=', '^=',
+                     '%=', '>>=', '<<=']
+_OPENING_BRACKETS = ['(', '[', '{']
+_CLOSING_BRACKETS = [')', ']', '}']
+_TAB_LENGTH = 8
+
+_EOL = frozenset([tokenize.NEWLINE, tokenize.NL, tokenize.COMMENT])
+_JUNK_TOKENS = (tokenize.COMMENT, tokenize.NL)
+
+# Whitespace checking policy constants
+_MUST = 0
+_MUST_NOT = 1
+_IGNORE = 2
+
+# Whitespace checking config constants
+_DICT_SEPARATOR = 'dict-separator'
+_TRAILING_COMMA = 'trailing-comma'
+_NO_SPACE_CHECK_CHOICES = [_TRAILING_COMMA, _DICT_SEPARATOR]
+
+MSGS = {
+    'C0301': ('Line too long (%s/%s)',
+              'line-too-long',
+              'Used when a line is longer than a given number of characters.'),
+    'C0302': ('Too many lines in module (%s/%s)', # was W0302
+              'too-many-lines',
+              'Used when a module has too much lines, reducing its readability.'
+             ),
+    'C0303': ('Trailing whitespace',
+              'trailing-whitespace',
+              'Used when there is whitespace between the end of a line and the '
+              'newline.'),
+    'C0304': ('Final newline missing',
+              'missing-final-newline',
+              'Used when the last line in a file is missing a newline.'),
+    'W0311': ('Bad indentation. Found %s %s, expected %s',
+              'bad-indentation',
+              'Used when an unexpected number of indentation\'s tabulations or '
+              'spaces has been found.'),
+    'C0330': ('Wrong %s indentation%s.\n%s%s',
+              'bad-continuation',
+              'TODO'),
+    'W0312': ('Found indentation with %ss instead of %ss',
+              'mixed-indentation',
+              'Used when there are some mixed tabs and spaces in a module.'),
+    'W0301': ('Unnecessary semicolon', # was W0106
+              'unnecessary-semicolon',
+              'Used when a statement is ended by a semi-colon (";"), which \
+              isn\'t necessary (that\'s python, not C ;).'),
+    'C0321': ('More than one statement on a single line',
+              'multiple-statements',
+              'Used when more than on statement are found on the same line.',
+              {'scope': WarningScope.NODE}),
+    'C0325' : ('Unnecessary parens after %r keyword',
+               'superfluous-parens',
+               'Used when a single item in parentheses follows an if, for, or '
+               'other keyword.'),
+    'C0326': ('%s space %s %s %s\n%s',
+              'bad-whitespace',
+              ('Used when a wrong number of spaces is used around an operator, '
+               'bracket or block opener.'),
+              {'old_names': [('C0323', 'no-space-after-operator'),
+                             ('C0324', 'no-space-after-comma'),
+                             ('C0322', 'no-space-before-operator')]}),
+    'W0332': ('Use of "l" as long integer identifier',
+              'lowercase-l-suffix',
+              'Used when a lower case "l" is used to mark a long integer. You '
+              'should use a upper case "L" since the letter "l" looks too much '
+              'like the digit "1"',
+              {'maxversion': (3, 0)}),
+    'C0327': ('Mixed line endings LF and CRLF',
+              'mixed-line-endings',
+              'Used when there are mixed (LF and CRLF) newline signs in a file.'),
+    'C0328': ('Unexpected line ending format. There is \'%s\' while it should be \'%s\'.',
+              'unexpected-line-ending-format',
+              'Used when there is different newline than expected.'),
+    }
+
+
+def _underline_token(token):
+    length = token[3][1] - token[2][1]
+    offset = token[2][1]
+    return token[4] + (' ' * offset) + ('^' * length)
+
+
+def _column_distance(token1, token2):
+    if token1 == token2:
+        return 0
+    if token2[3] < token1[3]:
+        token1, token2 = token2, token1
+    if token1[3][0] != token2[2][0]:
+        return None
+    return token2[2][1] - token1[3][1]
+
+
+def _last_token_on_line_is(tokens, line_end, token):
+    return (line_end > 0 and tokens.token(line_end-1) == token or
+            line_end > 1 and tokens.token(line_end-2) == token
+            and tokens.type(line_end-1) == tokenize.COMMENT)
+
+
+def _token_followed_by_eol(tokens, position):
+    return (tokens.type(position+1) == tokenize.NL or
+            tokens.type(position+1) == tokenize.COMMENT and
+            tokens.type(position+2) == tokenize.NL)
+
+
+def _get_indent_length(line):
+    """Return the length of the indentation on the given token's line."""
+    result = 0
+    for char in line:
+        if char == ' ':
+            result += 1
+        elif char == '\t':
+            result += _TAB_LENGTH
+        else:
+            break
+    return result
+
+
+def _get_indent_hint_line(bar_positions, bad_position):
+    """Return a line with |s for each of the positions in the given lists."""
+    if not bar_positions:
+        return ''
+    markers = [(pos, '|') for pos in bar_positions]
+    markers.append((bad_position, '^'))
+    markers.sort()
+    line = [' '] * (markers[-1][0] + 1)
+    for position, marker in markers:
+        line[position] = marker
+    return ''.join(line)
+
+
+class _ContinuedIndent(object):
+    __slots__ = ('valid_outdent_offsets',
+                 'valid_continuation_offsets',
+                 'context_type',
+                 'token',
+                 'position')
+
+    def __init__(self,
+                 context_type,
+                 token,
+                 position,
+                 valid_outdent_offsets,
+                 valid_continuation_offsets):
+        self.valid_outdent_offsets = valid_outdent_offsets
+        self.valid_continuation_offsets = valid_continuation_offsets
+        self.context_type = context_type
+        self.position = position
+        self.token = token
+
+
+# The contexts for hanging indents.
+# A hanging indented dictionary value after :
+HANGING_DICT_VALUE = 'dict-value'
+# Hanging indentation in an expression.
+HANGING = 'hanging'
+# Hanging indentation in a block header.
+HANGING_BLOCK = 'hanging-block'
+# Continued indentation inside an expression.
+CONTINUED = 'continued'
+# Continued indentation in a block header.
+CONTINUED_BLOCK = 'continued-block'
+
+SINGLE_LINE = 'single'
+WITH_BODY = 'multi'
+
+_CONTINUATION_MSG_PARTS = {
+    HANGING_DICT_VALUE: ('hanging', ' in dict value'),
+    HANGING: ('hanging', ''),
+    HANGING_BLOCK: ('hanging', ' before block'),
+    CONTINUED: ('continued', ''),
+    CONTINUED_BLOCK: ('continued', ' before block'),
+}
+
+
+def _Offsets(*args):
+    """Valid indentation offsets for a continued line."""
+    return dict((a, None) for a in args)
+
+
+def _BeforeBlockOffsets(single, with_body):
+    """Valid alternative indent offsets for continued lines before blocks.
+
+    :param single: Valid offset for statements on a single logical line.
+    :param with_body: Valid offset for statements on several lines.
+    """
+    return {single: SINGLE_LINE, with_body: WITH_BODY}
+
+
+class TokenWrapper(object):
+    """A wrapper for readable access to token information."""
+
+    def __init__(self, tokens):
+        self._tokens = tokens
+
+    def token(self, idx):
+        return self._tokens[idx][1]
+
+    def type(self, idx):
+        return self._tokens[idx][0]
+
+    def start_line(self, idx):
+        return self._tokens[idx][2][0]
+
+    def start_col(self, idx):
+        return self._tokens[idx][2][1]
+
+    def line(self, idx):
+        return self._tokens[idx][4]
+
+
+class ContinuedLineState(object):
+    """Tracker for continued indentation inside a logical line."""
+
+    def __init__(self, tokens, config):
+        self._line_start = -1
+        self._cont_stack = []
+        self._is_block_opener = False
+        self.retained_warnings = []
+        self._config = config
+        self._tokens = TokenWrapper(tokens)
+
+    @property
+    def has_content(self):
+        return bool(self._cont_stack)
+
+    @property
+    def _block_indent_size(self):
+        return len(self._config.indent_string.replace('\t', ' ' * _TAB_LENGTH))
+
+    @property
+    def _continuation_size(self):
+        return self._config.indent_after_paren
+
+    def handle_line_start(self, pos):
+        """Record the first non-junk token at the start of a line."""
+        if self._line_start > -1:
+            return
+        self._is_block_opener = self._tokens.token(pos) in _CONTINUATION_BLOCK_OPENERS
+        self._line_start = pos
+
+    def next_physical_line(self):
+        """Prepares the tracker for a new physical line (NL)."""
+        self._line_start = -1
+        self._is_block_opener = False
+
+    def next_logical_line(self):
+        """Prepares the tracker for a new logical line (NEWLINE).
+
+        A new logical line only starts with block indentation.
+        """
+        self.next_physical_line()
+        self.retained_warnings = []
+        self._cont_stack = []
+
+    def add_block_warning(self, token_position, state, valid_offsets):
+        self.retained_warnings.append((token_position, state, valid_offsets))
+
+    def get_valid_offsets(self, idx):
+        """"Returns the valid offsets for the token at the given position."""
+        # The closing brace on a dict or the 'for' in a dict comprehension may
+        # reset two indent levels because the dict value is ended implicitly
+        stack_top = -1
+        if self._tokens.token(idx) in ('}', 'for') and self._cont_stack[-1].token == ':':
+            stack_top = -2
+        indent = self._cont_stack[stack_top]
+        if self._tokens.token(idx) in _CLOSING_BRACKETS:
+            valid_offsets = indent.valid_outdent_offsets
+        else:
+            valid_offsets = indent.valid_continuation_offsets
+        return indent, valid_offsets.copy()
+
+    def _hanging_indent_after_bracket(self, bracket, position):
+        """Extracts indentation information for a hanging indent."""
+        indentation = _get_indent_length(self._tokens.line(position))
+        if self._is_block_opener and self._continuation_size == self._block_indent_size:
+            return _ContinuedIndent(
+                HANGING_BLOCK,
+                bracket,
+                position,
+                _Offsets(indentation + self._continuation_size, indentation),
+                _BeforeBlockOffsets(indentation + self._continuation_size,
+                                    indentation + self._continuation_size * 2))
+        elif bracket == ':':
+            # If the dict key was on the same line as the open brace, the new
+            # correct indent should be relative to the key instead of the
+            # current indent level
+            paren_align = self._cont_stack[-1].valid_outdent_offsets
+            next_align = self._cont_stack[-1].valid_continuation_offsets.copy()
+            next_align_keys = list(next_align.keys())
+            next_align[next_align_keys[0] + self._continuation_size] = True
+            # Note that the continuation of
+            # d = {
+            #       'a': 'b'
+            #            'c'
+            # }
+            # is handled by the special-casing for hanging continued string indents.
+            return _ContinuedIndent(HANGING_DICT_VALUE, bracket, position, paren_align, next_align)
+        else:
+            return _ContinuedIndent(
+                HANGING,
+                bracket,
+                position,
+                _Offsets(indentation, indentation + self._continuation_size),
+                _Offsets(indentation + self._continuation_size))
+
+    def _continuation_inside_bracket(self, bracket, pos):
+        """Extracts indentation information for a continued indent."""
+        indentation = _get_indent_length(self._tokens.line(pos))
+        if self._is_block_opener and self._tokens.start_col(pos+1) - indentation == self._block_indent_size:
+            return _ContinuedIndent(
+                CONTINUED_BLOCK,
+                bracket,
+                pos,
+                _Offsets(self._tokens.start_col(pos)),
+                _BeforeBlockOffsets(self._tokens.start_col(pos+1),
+                                    self._tokens.start_col(pos+1) + self._continuation_size))
+        else:
+            return _ContinuedIndent(
+                CONTINUED,
+                bracket,
+                pos,
+                _Offsets(self._tokens.start_col(pos)),
+                _Offsets(self._tokens.start_col(pos+1)))
+
+    def pop_token(self):
+        self._cont_stack.pop()
+
+    def push_token(self, token, position):
+        """Pushes a new token for continued indentation on the stack.
+
+        Tokens that can modify continued indentation offsets are:
+          * opening brackets
+          * 'lambda'
+          * : inside dictionaries
+
+        push_token relies on the caller to filter out those
+        interesting tokens.
+
+        :param token: The concrete token
+        :param position: The position of the token in the stream.
+        """
+        if _token_followed_by_eol(self._tokens, position):
+            self._cont_stack.append(
+                self._hanging_indent_after_bracket(token, position))
+        else:
+            self._cont_stack.append(
+                self._continuation_inside_bracket(token, position))
+
+
+class FormatChecker(BaseTokenChecker):
+    """checks for :
+    * unauthorized constructions
+    * strict indentation
+    * line length
+    """
+
+    __implements__ = (ITokenChecker, IAstroidChecker, IRawChecker)
+
+    # configuration section name
+    name = 'format'
+    # messages
+    msgs = MSGS
+    # configuration options
+    # for available dict keys/values see the optik parser 'add_option' method
+    options = (('max-line-length',
+                {'default' : 100, 'type' : "int", 'metavar' : '<int>',
+                 'help' : 'Maximum number of characters on a single line.'}),
+               ('ignore-long-lines',
+                {'type': 'regexp', 'metavar': '<regexp>',
+                 'default': r'^\s*(# )?<?https?://\S+>?$',
+                 'help': ('Regexp for a line that is allowed to be longer than '
+                          'the limit.')}),
+               ('single-line-if-stmt',
+                {'default': False, 'type' : 'yn', 'metavar' : '<y_or_n>',
+                 'help' : ('Allow the body of an if to be on the same '
+                           'line as the test if there is no else.')}),
+               ('no-space-check',
+                {'default': ','.join(_NO_SPACE_CHECK_CHOICES),
+                 'type': 'multiple_choice',
+                 'choices': _NO_SPACE_CHECK_CHOICES,
+                 'help': ('List of optional constructs for which whitespace '
+                          'checking is disabled')}),
+               ('max-module-lines',
+                {'default' : 1000, 'type' : 'int', 'metavar' : '<int>',
+                 'help': 'Maximum number of lines in a module'}
+               ),
+               ('indent-string',
+                {'default' : '    ', 'type' : "string", 'metavar' : '<string>',
+                 'help' : 'String used as indentation unit. This is usually '
+                          '"    " (4 spaces) or "\\t" (1 tab).'}),
+               ('indent-after-paren',
+                {'type': 'int', 'metavar': '<int>', 'default': 4,
+                 'help': 'Number of spaces of indent required inside a hanging '
+                         ' or continued line.'}),
+               ('expected-line-ending-format',
+                {'type': 'choice', 'metavar': '<empty or LF or CRLF>', 'default': '',
+                 'choices': ['', 'LF', 'CRLF'],
+                 'help': 'Expected format of line ending, e.g. empty (any line ending), LF or CRLF.'}),
+              )
+
+    def __init__(self, linter=None):
+        BaseTokenChecker.__init__(self, linter)
+        self._lines = None
+        self._visited_lines = None
+        self._bracket_stack = [None]
+
+    def _pop_token(self):
+        self._bracket_stack.pop()
+        self._current_line.pop_token()
+
+    def _push_token(self, token, idx):
+        self._bracket_stack.append(token)
+        self._current_line.push_token(token, idx)
+
+    def new_line(self, tokens, line_end, line_start):
+        """a new line has been encountered, process it if necessary"""
+        if _last_token_on_line_is(tokens, line_end, ';'):
+            self.add_message('unnecessary-semicolon', line=tokens.start_line(line_end))
+
+        line_num = tokens.start_line(line_start)
+        line = tokens.line(line_start)
+        if tokens.type(line_start) not in _JUNK_TOKENS:
+            self._lines[line_num] = line.split('\n')[0]
+        self.check_lines(line, line_num)
+
+    def process_module(self, module):
+        self._keywords_with_parens = set()
+        if 'print_function' in module.future_imports:
+            self._keywords_with_parens.add('print')
+
+    def _check_keyword_parentheses(self, tokens, start):
+        """Check that there are not unnecessary parens after a keyword.
+
+        Parens are unnecessary if there is exactly one balanced outer pair on a
+        line, and it is followed by a colon, and contains no commas (i.e. is not a
+        tuple).
+
+        Args:
+        tokens: list of Tokens; the entire list of Tokens.
+        start: int; the position of the keyword in the token list.
+        """
+        # If the next token is not a paren, we're fine.
+        if self._inside_brackets(':') and tokens[start][1] == 'for':
+            self._pop_token()
+        if tokens[start+1][1] != '(':
+            return
+
+        found_and_or = False
+        depth = 0
+        keyword_token = tokens[start][1]
+        line_num = tokens[start][2][0]
+
+        for i in range(start, len(tokens) - 1):
+            token = tokens[i]
+
+            # If we hit a newline, then assume any parens were for continuation.
+            if token[0] == tokenize.NL:
+                return
+
+            if token[1] == '(':
+                depth += 1
+            elif token[1] == ')':
+                depth -= 1
+                if not depth:
+                    # ')' can't happen after if (foo), since it would be a syntax error.
+                    if (tokens[i+1][1] in (':', ')', ']', '}', 'in') or
+                            tokens[i+1][0] in (tokenize.NEWLINE,
+                                               tokenize.ENDMARKER,
+                                               tokenize.COMMENT)):
+                        # The empty tuple () is always accepted.
+                        if i == start + 2:
+                            return
+                        if keyword_token == 'not':
+                            if not found_and_or:
+                                self.add_message('superfluous-parens', line=line_num,
+                                                 args=keyword_token)
+                        elif keyword_token in ('return', 'yield'):
+                            self.add_message('superfluous-parens', line=line_num,
+                                             args=keyword_token)
+                        elif keyword_token not in self._keywords_with_parens:
+                            if not (tokens[i+1][1] == 'in' and found_and_or):
+                                self.add_message('superfluous-parens', line=line_num,
+                                                 args=keyword_token)
+                    return
+            elif depth == 1:
+                # This is a tuple, which is always acceptable.
+                if token[1] == ',':
+                    return
+                # 'and' and 'or' are the only boolean operators with lower precedence
+                # than 'not', so parens are only required when they are found.
+                elif token[1] in ('and', 'or'):
+                    found_and_or = True
+                # A yield inside an expression must always be in parentheses,
+                # quit early without error.
+                elif token[1] == 'yield':
+                    return
+                # A generator expression always has a 'for' token in it, and
+                # the 'for' token is only legal inside parens when it is in a
+                # generator expression.  The parens are necessary here, so bail
+                # without an error.
+                elif token[1] == 'for':
+                    return
+
+    def _opening_bracket(self, tokens, i):
+        self._push_token(tokens[i][1], i)
+        # Special case: ignore slices
+        if tokens[i][1] == '[' and tokens[i+1][1] == ':':
+            return
+
+        if (i > 0 and (tokens[i-1][0] == tokenize.NAME and
+                       not (keyword.iskeyword(tokens[i-1][1]))
+                       or tokens[i-1][1] in _CLOSING_BRACKETS)):
+            self._check_space(tokens, i, (_MUST_NOT, _MUST_NOT))
+        else:
+            self._check_space(tokens, i, (_IGNORE, _MUST_NOT))
+
+    def _closing_bracket(self, tokens, i):
+        if self._inside_brackets(':'):
+            self._pop_token()
+        self._pop_token()
+        # Special case: ignore slices
+        if tokens[i-1][1] == ':' and tokens[i][1] == ']':
+            return
+        policy_before = _MUST_NOT
+        if tokens[i][1] in _CLOSING_BRACKETS and tokens[i-1][1] == ',':
+            if _TRAILING_COMMA in self.config.no_space_check:
+                policy_before = _IGNORE
+
+        self._check_space(tokens, i, (policy_before, _IGNORE))
+
+    def _check_equals_spacing(self, tokens, i):
+        """Check the spacing of a single equals sign."""
+        if self._inside_brackets('(') or self._inside_brackets('lambda'):
+            self._check_space(tokens, i, (_MUST_NOT, _MUST_NOT))
+        else:
+            self._check_space(tokens, i, (_MUST, _MUST))
+
+    def _open_lambda(self, tokens, i): # pylint:disable=unused-argument
+        self._push_token('lambda', i)
+
+    def _handle_colon(self, tokens, i):
+        # Special case: ignore slices
+        if self._inside_brackets('['):
+            return
+        if (self._inside_brackets('{') and
+                _DICT_SEPARATOR in self.config.no_space_check):
+            policy = (_IGNORE, _IGNORE)
+        else:
+            policy = (_MUST_NOT, _MUST)
+        self._check_space(tokens, i, policy)
+
+        if self._inside_brackets('lambda'):
+            self._pop_token()
+        elif self._inside_brackets('{'):
+            self._push_token(':', i)
+
+    def _handle_comma(self, tokens, i):
+        # Only require a following whitespace if this is
+        # not a hanging comma before a closing bracket.
+        if tokens[i+1][1] in _CLOSING_BRACKETS:
+            self._check_space(tokens, i, (_MUST_NOT, _IGNORE))
+        else:
+            self._check_space(tokens, i, (_MUST_NOT, _MUST))
+        if self._inside_brackets(':'):
+            self._pop_token()
+
+    def _check_surrounded_by_space(self, tokens, i):
+        """Check that a binary operator is surrounded by exactly one space."""
+        self._check_space(tokens, i, (_MUST, _MUST))
+
+    def _check_space(self, tokens, i, policies):
+        def _policy_string(policy):
+            if policy == _MUST:
+                return 'Exactly one', 'required'
+            else:
+                return 'No', 'allowed'
+
+        def _name_construct(token):
+            if token[1] == ',':
+                return 'comma'
+            elif token[1] == ':':
+                return ':'
+            elif token[1] in '()[]{}':
+                return 'bracket'
+            elif token[1] in ('<', '>', '<=', '>=', '!=', '=='):
+                return 'comparison'
+            else:
+                if self._inside_brackets('('):
+                    return 'keyword argument assignment'
+                else:
+                    return 'assignment'
+
+        good_space = [True, True]
+        token = tokens[i]
+        pairs = [(tokens[i-1], token), (token, tokens[i+1])]
+
+        for other_idx, (policy, token_pair) in enumerate(zip(policies, pairs)):
+            if token_pair[other_idx][0] in _EOL or policy == _IGNORE:
+                continue
+
+            distance = _column_distance(*token_pair)
+            if distance is None:
+                continue
+            good_space[other_idx] = (
+                (policy == _MUST and distance == 1) or
+                (policy == _MUST_NOT and distance == 0))
+
+        warnings = []
+        if not any(good_space) and policies[0] == policies[1]:
+            warnings.append((policies[0], 'around'))
+        else:
+            for ok, policy, position in zip(good_space, policies, ('before', 'after')):
+                if not ok:
+                    warnings.append((policy, position))
+        for policy, position in warnings:
+            construct = _name_construct(token)
+            count, state = _policy_string(policy)
+            self.add_message('bad-whitespace', line=token[2][0],
+                             args=(count, state, position, construct,
+                                   _underline_token(token)))
+
+    def _inside_brackets(self, left):
+        return self._bracket_stack[-1] == left
+
+    def _prepare_token_dispatcher(self):
+        raw = [
+            (_KEYWORD_TOKENS,
+             self._check_keyword_parentheses),
+
+            (_OPENING_BRACKETS, self._opening_bracket),
+
+            (_CLOSING_BRACKETS, self._closing_bracket),
+
+            (['='], self._check_equals_spacing),
+
+            (_SPACED_OPERATORS, self._check_surrounded_by_space),
+
+            ([','], self._handle_comma),
+
+            ([':'], self._handle_colon),
+
+            (['lambda'], self._open_lambda),
+
+            ]
+
+        dispatch = {}
+        for tokens, handler in raw:
+            for token in tokens:
+                dispatch[token] = handler
+        return dispatch
+
+    def process_tokens(self, tokens):
+        """process tokens and search for :
+
+         _ non strict indentation (i.e. not always using the <indent> parameter as
+           indent unit)
+         _ too long lines (i.e. longer than <max_chars>)
+         _ optionally bad construct (if given, bad_construct must be a compiled
+           regular expression).
+        """
+        self._bracket_stack = [None]
+        indents = [0]
+        check_equal = False
+        line_num = 0
+        self._lines = {}
+        self._visited_lines = {}
+        token_handlers = self._prepare_token_dispatcher()
+        self._last_line_ending = None
+
+        self._current_line = ContinuedLineState(tokens, self.config)
+        for idx, (tok_type, token, start, _, line) in enumerate(tokens):
+            if start[0] != line_num:
+                line_num = start[0]
+                # A tokenizer oddity: if an indented line contains a multi-line
+                # docstring, the line member of the INDENT token does not contain
+                # the full line; therefore we check the next token on the line.
+                if tok_type == tokenize.INDENT:
+                    self.new_line(TokenWrapper(tokens), idx-1, idx+1)
+                else:
+                    self.new_line(TokenWrapper(tokens), idx-1, idx)
+
+            if tok_type == tokenize.NEWLINE:
+                # a program statement, or ENDMARKER, will eventually follow,
+                # after some (possibly empty) run of tokens of the form
+                #     (NL | COMMENT)* (INDENT | DEDENT+)?
+                # If an INDENT appears, setting check_equal is wrong, and will
+                # be undone when we see the INDENT.
+                check_equal = True
+                self._process_retained_warnings(TokenWrapper(tokens), idx)
+                self._current_line.next_logical_line()
+                self._check_line_ending(token, line_num)
+            elif tok_type == tokenize.INDENT:
+                check_equal = False
+                self.check_indent_level(token, indents[-1]+1, line_num)
+                indents.append(indents[-1]+1)
+            elif tok_type == tokenize.DEDENT:
+                # there's nothing we need to check here!  what's important is
+                # that when the run of DEDENTs ends, the indentation of the
+                # program statement (or ENDMARKER) that triggered the run is
+                # equal to what's left at the top of the indents stack
+                check_equal = True
+                if len(indents) > 1:
+                    del indents[-1]
+            elif tok_type == tokenize.NL:
+                self._check_continued_indentation(TokenWrapper(tokens), idx+1)
+                self._current_line.next_physical_line()
+            elif tok_type != tokenize.COMMENT:
+                self._current_line.handle_line_start(idx)
+                # This is the first concrete token following a NEWLINE, so it
+                # must be the first token of the next program statement, or an
+                # ENDMARKER; the "line" argument exposes the leading whitespace
+                # for this statement; in the case of ENDMARKER, line is an empty
+                # string, so will properly match the empty string with which the
+                # "indents" stack was seeded
+                if check_equal:
+                    check_equal = False
+                    self.check_indent_level(line, indents[-1], line_num)
+
+            if tok_type == tokenize.NUMBER and token.endswith('l'):
+                self.add_message('lowercase-l-suffix', line=line_num)
+
+            try:
+                handler = token_handlers[token]
+            except KeyError:
+                pass
+            else:
+                handler(tokens, idx)
+
+        line_num -= 1 # to be ok with "wc -l"
+        if line_num > self.config.max_module_lines:
+            # Get the line where the too-many-lines (or its message id)
+            # was disabled or default to 1.
+            symbol = self.linter.msgs_store.check_message_id('too-many-lines')
+            names = (symbol.msgid, 'too-many-lines')
+            line = next(filter(None,
+                               map(self.linter._pragma_lineno.get, names)), 1)
+            self.add_message('too-many-lines',
+                             args=(line_num, self.config.max_module_lines),
+                             line=line)
+
+    def _check_line_ending(self, line_ending, line_num):
+        # check if line endings are mixed
+        if self._last_line_ending is not None:
+            if line_ending != self._last_line_ending:
+                self.add_message('mixed-line-endings', line=line_num)
+
+        self._last_line_ending = line_ending
+
+        # check if line ending is as expected
+        expected = self.config.expected_line_ending_format
+        if expected:
+            line_ending = reduce(lambda x, y: x + y if x != y else x, line_ending, "")  # reduce multiple \n\n\n\n to one \n
+            line_ending = 'LF' if line_ending == '\n' else 'CRLF'
+            if line_ending != expected:
+                self.add_message('unexpected-line-ending-format', args=(line_ending, expected), line=line_num)
+
+
+    def _process_retained_warnings(self, tokens, current_pos):
+        single_line_block_stmt = not _last_token_on_line_is(tokens, current_pos, ':')
+
+        for indent_pos, state, offsets in self._current_line.retained_warnings:
+            block_type = offsets[tokens.start_col(indent_pos)]
+            hints = dict((k, v) for k, v in six.iteritems(offsets)
+                         if v != block_type)
+            if single_line_block_stmt and block_type == WITH_BODY:
+                self._add_continuation_message(state, hints, tokens, indent_pos)
+            elif not single_line_block_stmt and block_type == SINGLE_LINE:
+                self._add_continuation_message(state, hints, tokens, indent_pos)
+
+    def _check_continued_indentation(self, tokens, next_idx):
+        def same_token_around_nl(token_type):
+            return (tokens.type(next_idx) == token_type and
+                    tokens.type(next_idx-2) == token_type)
+
+        # Do not issue any warnings if the next line is empty.
+        if not self._current_line.has_content or tokens.type(next_idx) == tokenize.NL:
+            return
+
+        state, valid_offsets = self._current_line.get_valid_offsets(next_idx)
+        # Special handling for hanging comments and strings. If the last line ended
+        # with a comment (string) and the new line contains only a comment, the line
+        # may also be indented to the start of the previous token.
+        if same_token_around_nl(tokenize.COMMENT) or same_token_around_nl(tokenize.STRING):
+            valid_offsets[tokens.start_col(next_idx-2)] = True
+
+        # We can only decide if the indentation of a continued line before opening
+        # a new block is valid once we know of the body of the block is on the
+        # same line as the block opener. Since the token processing is single-pass,
+        # emitting those warnings is delayed until the block opener is processed.
+        if (state.context_type in (HANGING_BLOCK, CONTINUED_BLOCK)
+                and tokens.start_col(next_idx) in valid_offsets):
+            self._current_line.add_block_warning(next_idx, state, valid_offsets)
+        elif tokens.start_col(next_idx) not in valid_offsets:
+            self._add_continuation_message(state, valid_offsets, tokens, next_idx)
+
+    def _add_continuation_message(self, state, offsets, tokens, position):
+        readable_type, readable_position = _CONTINUATION_MSG_PARTS[state.context_type]
+        hint_line = _get_indent_hint_line(offsets, tokens.start_col(position))
+        self.add_message(
+            'bad-continuation',
+            line=tokens.start_line(position),
+            args=(readable_type, readable_position, tokens.line(position), hint_line))
+
+    @check_messages('multiple-statements')
+    def visit_default(self, node):
+        """check the node line number and check it if not yet done"""
+        if not node.is_statement:
+            return
+        if not node.root().pure_python:
+            return # XXX block visit of child nodes
+        prev_sibl = node.previous_sibling()
+        if prev_sibl is not None:
+            prev_line = prev_sibl.fromlineno
+        else:
+            # The line on which a finally: occurs in a try/finally
+            # is not directly represented in the AST. We infer it
+            # by taking the last line of the body and adding 1, which
+            # should be the line of finally:
+            if (isinstance(node.parent, nodes.TryFinally)
+                    and node in node.parent.finalbody):
+                prev_line = node.parent.body[0].tolineno + 1
+            else:
+                prev_line = node.parent.statement().fromlineno
+        line = node.fromlineno
+        assert line, node
+        if prev_line == line and self._visited_lines.get(line) != 2:
+            self._check_multi_statement_line(node, line)
+            return
+        if line in self._visited_lines:
+            return
+        try:
+            tolineno = node.blockstart_tolineno
+        except AttributeError:
+            tolineno = node.tolineno
+        assert tolineno, node
+        lines = []
+        for line in range(line, tolineno + 1):
+            self._visited_lines[line] = 1
+            try:
+                lines.append(self._lines[line].rstrip())
+            except KeyError:
+                lines.append('')
+
+    def _check_multi_statement_line(self, node, line):
+        """Check for lines containing multiple statements."""
+        # Do not warn about multiple nested context managers
+        # in with statements.
+        if isinstance(node, nodes.With):
+            return
+        # For try... except... finally..., the two nodes
+        # appear to be on the same line due to how the AST is built.
+        if (isinstance(node, nodes.TryExcept) and
+                isinstance(node.parent, nodes.TryFinally)):
+            return
+        if (isinstance(node.parent, nodes.If) and not node.parent.orelse
+                and self.config.single_line_if_stmt):
+            return
+        self.add_message('multiple-statements', node=node)
+        self._visited_lines[line] = 2
+
+    def check_lines(self, lines, i):
+        """check lines have less than a maximum number of characters
+        """
+        max_chars = self.config.max_line_length
+        ignore_long_line = self.config.ignore_long_lines
+
+        for line in lines.splitlines(True):
+            if not line.endswith('\n'):
+                self.add_message('missing-final-newline', line=i)
+            else:
+                stripped_line = line.rstrip()
+                if line[len(stripped_line):] not in ('\n', '\r\n'):
+                    self.add_message('trailing-whitespace', line=i)
+                # Don't count excess whitespace in the line length.
+                line = stripped_line
+            mobj = OPTION_RGX.search(line)
+            if mobj and mobj.group(1).split('=', 1)[0].strip() == 'disable':
+                line = line.split('#')[0].rstrip()
+
+            if len(line) > max_chars and not ignore_long_line.search(line):
+                self.add_message('line-too-long', line=i, args=(len(line), max_chars))
+            i += 1
+
+    def check_indent_level(self, string, expected, line_num):
+        """return the indent level of the string
+        """
+        indent = self.config.indent_string
+        if indent == '\\t': # \t is not interpreted in the configuration file
+            indent = '\t'
+        level = 0
+        unit_size = len(indent)
+        while string[:unit_size] == indent:
+            string = string[unit_size:]
+            level += 1
+        suppl = ''
+        while string and string[0] in ' \t':
+            if string[0] != indent[0]:
+                if string[0] == '\t':
+                    args = ('tab', 'space')
+                else:
+                    args = ('space', 'tab')
+                self.add_message('mixed-indentation', args=args, line=line_num)
+                return level
+            suppl += string[0]
+            string = string[1:]
+        if level != expected or suppl:
+            i_type = 'spaces'
+            if indent[0] == '\t':
+                i_type = 'tabs'
+            self.add_message('bad-indentation', line=line_num,
+                             args=(level * unit_size + len(suppl), i_type,
+                                   expected * unit_size))
+
+
+def register(linter):
+    """required method to auto register this checker """
+    linter.register_checker(FormatChecker(linter))