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Diffstat (limited to 'third_party/python/Jinja2/jinja2/lexer.py')
| -rw-r--r-- | third_party/python/Jinja2/jinja2/lexer.py | 848 |
1 files changed, 848 insertions, 0 deletions
diff --git a/third_party/python/Jinja2/jinja2/lexer.py b/third_party/python/Jinja2/jinja2/lexer.py new file mode 100644 index 0000000000..552356a12d --- /dev/null +++ b/third_party/python/Jinja2/jinja2/lexer.py @@ -0,0 +1,848 @@ +# -*- coding: utf-8 -*- +"""Implements a Jinja / Python combination lexer. The ``Lexer`` class +is used to do some preprocessing. It filters out invalid operators like +the bitshift operators we don't allow in templates. It separates +template code and python code in expressions. +""" +import re +from ast import literal_eval +from collections import deque +from operator import itemgetter + +from ._compat import implements_iterator +from ._compat import intern +from ._compat import iteritems +from ._compat import text_type +from .exceptions import TemplateSyntaxError +from .utils import LRUCache + +# cache for the lexers. Exists in order to be able to have multiple +# environments with the same lexer +_lexer_cache = LRUCache(50) + +# static regular expressions +whitespace_re = re.compile(r"\s+", re.U) +newline_re = re.compile(r"(\r\n|\r|\n)") +string_re = re.compile( + r"('([^'\\]*(?:\\.[^'\\]*)*)'" r'|"([^"\\]*(?:\\.[^"\\]*)*)")', re.S +) +integer_re = re.compile(r"(\d+_)*\d+") +float_re = re.compile( + r""" + (?<!\.) # doesn't start with a . + (\d+_)*\d+ # digits, possibly _ separated + ( + (\.(\d+_)*\d+)? # optional fractional part + e[+\-]?(\d+_)*\d+ # exponent part + | + \.(\d+_)*\d+ # required fractional part + ) + """, + re.IGNORECASE | re.VERBOSE, +) + +try: + # check if this Python supports Unicode identifiers + compile("föö", "<unknown>", "eval") +except SyntaxError: + # Python 2, no Unicode support, use ASCII identifiers + name_re = re.compile(r"[a-zA-Z_][a-zA-Z0-9_]*") + check_ident = False +else: + # Unicode support, import generated re pattern and set flag to use + # str.isidentifier to validate during lexing. + from ._identifier import pattern as name_re + + check_ident = True + +# internal the tokens and keep references to them +TOKEN_ADD = intern("add") +TOKEN_ASSIGN = intern("assign") +TOKEN_COLON = intern("colon") +TOKEN_COMMA = intern("comma") +TOKEN_DIV = intern("div") +TOKEN_DOT = intern("dot") +TOKEN_EQ = intern("eq") +TOKEN_FLOORDIV = intern("floordiv") +TOKEN_GT = intern("gt") +TOKEN_GTEQ = intern("gteq") +TOKEN_LBRACE = intern("lbrace") +TOKEN_LBRACKET = intern("lbracket") +TOKEN_LPAREN = intern("lparen") +TOKEN_LT = intern("lt") +TOKEN_LTEQ = intern("lteq") +TOKEN_MOD = intern("mod") +TOKEN_MUL = intern("mul") +TOKEN_NE = intern("ne") +TOKEN_PIPE = intern("pipe") +TOKEN_POW = intern("pow") +TOKEN_RBRACE = intern("rbrace") +TOKEN_RBRACKET = intern("rbracket") +TOKEN_RPAREN = intern("rparen") +TOKEN_SEMICOLON = intern("semicolon") +TOKEN_SUB = intern("sub") +TOKEN_TILDE = intern("tilde") +TOKEN_WHITESPACE = intern("whitespace") +TOKEN_FLOAT = intern("float") +TOKEN_INTEGER = intern("integer") +TOKEN_NAME = intern("name") +TOKEN_STRING = intern("string") +TOKEN_OPERATOR = intern("operator") +TOKEN_BLOCK_BEGIN = intern("block_begin") +TOKEN_BLOCK_END = intern("block_end") +TOKEN_VARIABLE_BEGIN = intern("variable_begin") +TOKEN_VARIABLE_END = intern("variable_end") +TOKEN_RAW_BEGIN = intern("raw_begin") +TOKEN_RAW_END = intern("raw_end") +TOKEN_COMMENT_BEGIN = intern("comment_begin") +TOKEN_COMMENT_END = intern("comment_end") +TOKEN_COMMENT = intern("comment") +TOKEN_LINESTATEMENT_BEGIN = intern("linestatement_begin") +TOKEN_LINESTATEMENT_END = intern("linestatement_end") +TOKEN_LINECOMMENT_BEGIN = intern("linecomment_begin") +TOKEN_LINECOMMENT_END = intern("linecomment_end") +TOKEN_LINECOMMENT = intern("linecomment") +TOKEN_DATA = intern("data") +TOKEN_INITIAL = intern("initial") +TOKEN_EOF = intern("eof") + +# bind operators to token types +operators = { + "+": TOKEN_ADD, + "-": TOKEN_SUB, + "/": TOKEN_DIV, + "//": TOKEN_FLOORDIV, + "*": TOKEN_MUL, + "%": TOKEN_MOD, + "**": TOKEN_POW, + "~": TOKEN_TILDE, + "[": TOKEN_LBRACKET, + "]": TOKEN_RBRACKET, + "(": TOKEN_LPAREN, + ")": TOKEN_RPAREN, + "{": TOKEN_LBRACE, + "}": TOKEN_RBRACE, + "==": TOKEN_EQ, + "!=": TOKEN_NE, + ">": TOKEN_GT, + ">=": TOKEN_GTEQ, + "<": TOKEN_LT, + "<=": TOKEN_LTEQ, + "=": TOKEN_ASSIGN, + ".": TOKEN_DOT, + ":": TOKEN_COLON, + "|": TOKEN_PIPE, + ",": TOKEN_COMMA, + ";": TOKEN_SEMICOLON, +} + +reverse_operators = dict([(v, k) for k, v in iteritems(operators)]) +assert len(operators) == len(reverse_operators), "operators dropped" +operator_re = re.compile( + "(%s)" % "|".join(re.escape(x) for x in sorted(operators, key=lambda x: -len(x))) +) + +ignored_tokens = frozenset( + [ + TOKEN_COMMENT_BEGIN, + TOKEN_COMMENT, + TOKEN_COMMENT_END, + TOKEN_WHITESPACE, + TOKEN_LINECOMMENT_BEGIN, + TOKEN_LINECOMMENT_END, + TOKEN_LINECOMMENT, + ] +) +ignore_if_empty = frozenset( + [TOKEN_WHITESPACE, TOKEN_DATA, TOKEN_COMMENT, TOKEN_LINECOMMENT] +) + + +def _describe_token_type(token_type): + if token_type in reverse_operators: + return reverse_operators[token_type] + return { + TOKEN_COMMENT_BEGIN: "begin of comment", + TOKEN_COMMENT_END: "end of comment", + TOKEN_COMMENT: "comment", + TOKEN_LINECOMMENT: "comment", + TOKEN_BLOCK_BEGIN: "begin of statement block", + TOKEN_BLOCK_END: "end of statement block", + TOKEN_VARIABLE_BEGIN: "begin of print statement", + TOKEN_VARIABLE_END: "end of print statement", + TOKEN_LINESTATEMENT_BEGIN: "begin of line statement", + TOKEN_LINESTATEMENT_END: "end of line statement", + TOKEN_DATA: "template data / text", + TOKEN_EOF: "end of template", + }.get(token_type, token_type) + + +def describe_token(token): + """Returns a description of the token.""" + if token.type == TOKEN_NAME: + return token.value + return _describe_token_type(token.type) + + +def describe_token_expr(expr): + """Like `describe_token` but for token expressions.""" + if ":" in expr: + type, value = expr.split(":", 1) + if type == TOKEN_NAME: + return value + else: + type = expr + return _describe_token_type(type) + + +def count_newlines(value): + """Count the number of newline characters in the string. This is + useful for extensions that filter a stream. + """ + return len(newline_re.findall(value)) + + +def compile_rules(environment): + """Compiles all the rules from the environment into a list of rules.""" + e = re.escape + rules = [ + ( + len(environment.comment_start_string), + TOKEN_COMMENT_BEGIN, + e(environment.comment_start_string), + ), + ( + len(environment.block_start_string), + TOKEN_BLOCK_BEGIN, + e(environment.block_start_string), + ), + ( + len(environment.variable_start_string), + TOKEN_VARIABLE_BEGIN, + e(environment.variable_start_string), + ), + ] + + if environment.line_statement_prefix is not None: + rules.append( + ( + len(environment.line_statement_prefix), + TOKEN_LINESTATEMENT_BEGIN, + r"^[ \t\v]*" + e(environment.line_statement_prefix), + ) + ) + if environment.line_comment_prefix is not None: + rules.append( + ( + len(environment.line_comment_prefix), + TOKEN_LINECOMMENT_BEGIN, + r"(?:^|(?<=\S))[^\S\r\n]*" + e(environment.line_comment_prefix), + ) + ) + + return [x[1:] for x in sorted(rules, reverse=True)] + + +class Failure(object): + """Class that raises a `TemplateSyntaxError` if called. + Used by the `Lexer` to specify known errors. + """ + + def __init__(self, message, cls=TemplateSyntaxError): + self.message = message + self.error_class = cls + + def __call__(self, lineno, filename): + raise self.error_class(self.message, lineno, filename) + + +class Token(tuple): + """Token class.""" + + __slots__ = () + lineno, type, value = (property(itemgetter(x)) for x in range(3)) + + def __new__(cls, lineno, type, value): + return tuple.__new__(cls, (lineno, intern(str(type)), value)) + + def __str__(self): + if self.type in reverse_operators: + return reverse_operators[self.type] + elif self.type == "name": + return self.value + return self.type + + def test(self, expr): + """Test a token against a token expression. This can either be a + token type or ``'token_type:token_value'``. This can only test + against string values and types. + """ + # here we do a regular string equality check as test_any is usually + # passed an iterable of not interned strings. + if self.type == expr: + return True + elif ":" in expr: + return expr.split(":", 1) == [self.type, self.value] + return False + + def test_any(self, *iterable): + """Test against multiple token expressions.""" + for expr in iterable: + if self.test(expr): + return True + return False + + def __repr__(self): + return "Token(%r, %r, %r)" % (self.lineno, self.type, self.value) + + +@implements_iterator +class TokenStreamIterator(object): + """The iterator for tokenstreams. Iterate over the stream + until the eof token is reached. + """ + + def __init__(self, stream): + self.stream = stream + + def __iter__(self): + return self + + def __next__(self): + token = self.stream.current + if token.type is TOKEN_EOF: + self.stream.close() + raise StopIteration() + next(self.stream) + return token + + +@implements_iterator +class TokenStream(object): + """A token stream is an iterable that yields :class:`Token`\\s. The + parser however does not iterate over it but calls :meth:`next` to go + one token ahead. The current active token is stored as :attr:`current`. + """ + + def __init__(self, generator, name, filename): + self._iter = iter(generator) + self._pushed = deque() + self.name = name + self.filename = filename + self.closed = False + self.current = Token(1, TOKEN_INITIAL, "") + next(self) + + def __iter__(self): + return TokenStreamIterator(self) + + def __bool__(self): + return bool(self._pushed) or self.current.type is not TOKEN_EOF + + __nonzero__ = __bool__ # py2 + + @property + def eos(self): + """Are we at the end of the stream?""" + return not self + + def push(self, token): + """Push a token back to the stream.""" + self._pushed.append(token) + + def look(self): + """Look at the next token.""" + old_token = next(self) + result = self.current + self.push(result) + self.current = old_token + return result + + def skip(self, n=1): + """Got n tokens ahead.""" + for _ in range(n): + next(self) + + def next_if(self, expr): + """Perform the token test and return the token if it matched. + Otherwise the return value is `None`. + """ + if self.current.test(expr): + return next(self) + + def skip_if(self, expr): + """Like :meth:`next_if` but only returns `True` or `False`.""" + return self.next_if(expr) is not None + + def __next__(self): + """Go one token ahead and return the old one. + + Use the built-in :func:`next` instead of calling this directly. + """ + rv = self.current + if self._pushed: + self.current = self._pushed.popleft() + elif self.current.type is not TOKEN_EOF: + try: + self.current = next(self._iter) + except StopIteration: + self.close() + return rv + + def close(self): + """Close the stream.""" + self.current = Token(self.current.lineno, TOKEN_EOF, "") + self._iter = None + self.closed = True + + def expect(self, expr): + """Expect a given token type and return it. This accepts the same + argument as :meth:`jinja2.lexer.Token.test`. + """ + if not self.current.test(expr): + expr = describe_token_expr(expr) + if self.current.type is TOKEN_EOF: + raise TemplateSyntaxError( + "unexpected end of template, expected %r." % expr, + self.current.lineno, + self.name, + self.filename, + ) + raise TemplateSyntaxError( + "expected token %r, got %r" % (expr, describe_token(self.current)), + self.current.lineno, + self.name, + self.filename, + ) + try: + return self.current + finally: + next(self) + + +def get_lexer(environment): + """Return a lexer which is probably cached.""" + key = ( + environment.block_start_string, + environment.block_end_string, + environment.variable_start_string, + environment.variable_end_string, + environment.comment_start_string, + environment.comment_end_string, + environment.line_statement_prefix, + environment.line_comment_prefix, + environment.trim_blocks, + environment.lstrip_blocks, + environment.newline_sequence, + environment.keep_trailing_newline, + ) + lexer = _lexer_cache.get(key) + if lexer is None: + lexer = Lexer(environment) + _lexer_cache[key] = lexer + return lexer + + +class OptionalLStrip(tuple): + """A special tuple for marking a point in the state that can have + lstrip applied. + """ + + __slots__ = () + + # Even though it looks like a no-op, creating instances fails + # without this. + def __new__(cls, *members, **kwargs): + return super(OptionalLStrip, cls).__new__(cls, members) + + +class Lexer(object): + """Class that implements a lexer for a given environment. Automatically + created by the environment class, usually you don't have to do that. + + Note that the lexer is not automatically bound to an environment. + Multiple environments can share the same lexer. + """ + + def __init__(self, environment): + # shortcuts + e = re.escape + + def c(x): + return re.compile(x, re.M | re.S) + + # lexing rules for tags + tag_rules = [ + (whitespace_re, TOKEN_WHITESPACE, None), + (float_re, TOKEN_FLOAT, None), + (integer_re, TOKEN_INTEGER, None), + (name_re, TOKEN_NAME, None), + (string_re, TOKEN_STRING, None), + (operator_re, TOKEN_OPERATOR, None), + ] + + # assemble the root lexing rule. because "|" is ungreedy + # we have to sort by length so that the lexer continues working + # as expected when we have parsing rules like <% for block and + # <%= for variables. (if someone wants asp like syntax) + # variables are just part of the rules if variable processing + # is required. + root_tag_rules = compile_rules(environment) + + # block suffix if trimming is enabled + block_suffix_re = environment.trim_blocks and "\\n?" or "" + + # If lstrip is enabled, it should not be applied if there is any + # non-whitespace between the newline and block. + self.lstrip_unless_re = c(r"[^ \t]") if environment.lstrip_blocks else None + + self.newline_sequence = environment.newline_sequence + self.keep_trailing_newline = environment.keep_trailing_newline + + # global lexing rules + self.rules = { + "root": [ + # directives + ( + c( + "(.*?)(?:%s)" + % "|".join( + [ + r"(?P<raw_begin>%s(\-|\+|)\s*raw\s*(?:\-%s\s*|%s))" + % ( + e(environment.block_start_string), + e(environment.block_end_string), + e(environment.block_end_string), + ) + ] + + [ + r"(?P<%s>%s(\-|\+|))" % (n, r) + for n, r in root_tag_rules + ] + ) + ), + OptionalLStrip(TOKEN_DATA, "#bygroup"), + "#bygroup", + ), + # data + (c(".+"), TOKEN_DATA, None), + ], + # comments + TOKEN_COMMENT_BEGIN: [ + ( + c( + r"(.*?)((?:\-%s\s*|%s)%s)" + % ( + e(environment.comment_end_string), + e(environment.comment_end_string), + block_suffix_re, + ) + ), + (TOKEN_COMMENT, TOKEN_COMMENT_END), + "#pop", + ), + (c("(.)"), (Failure("Missing end of comment tag"),), None), + ], + # blocks + TOKEN_BLOCK_BEGIN: [ + ( + c( + r"(?:\-%s\s*|%s)%s" + % ( + e(environment.block_end_string), + e(environment.block_end_string), + block_suffix_re, + ) + ), + TOKEN_BLOCK_END, + "#pop", + ), + ] + + tag_rules, + # variables + TOKEN_VARIABLE_BEGIN: [ + ( + c( + r"\-%s\s*|%s" + % ( + e(environment.variable_end_string), + e(environment.variable_end_string), + ) + ), + TOKEN_VARIABLE_END, + "#pop", + ) + ] + + tag_rules, + # raw block + TOKEN_RAW_BEGIN: [ + ( + c( + r"(.*?)((?:%s(\-|\+|))\s*endraw\s*(?:\-%s\s*|%s%s))" + % ( + e(environment.block_start_string), + e(environment.block_end_string), + e(environment.block_end_string), + block_suffix_re, + ) + ), + OptionalLStrip(TOKEN_DATA, TOKEN_RAW_END), + "#pop", + ), + (c("(.)"), (Failure("Missing end of raw directive"),), None), + ], + # line statements + TOKEN_LINESTATEMENT_BEGIN: [ + (c(r"\s*(\n|$)"), TOKEN_LINESTATEMENT_END, "#pop") + ] + + tag_rules, + # line comments + TOKEN_LINECOMMENT_BEGIN: [ + ( + c(r"(.*?)()(?=\n|$)"), + (TOKEN_LINECOMMENT, TOKEN_LINECOMMENT_END), + "#pop", + ) + ], + } + + def _normalize_newlines(self, value): + """Called for strings and template data to normalize it to unicode.""" + return newline_re.sub(self.newline_sequence, value) + + def tokenize(self, source, name=None, filename=None, state=None): + """Calls tokeniter + tokenize and wraps it in a token stream.""" + stream = self.tokeniter(source, name, filename, state) + return TokenStream(self.wrap(stream, name, filename), name, filename) + + def wrap(self, stream, name=None, filename=None): + """This is called with the stream as returned by `tokenize` and wraps + every token in a :class:`Token` and converts the value. + """ + for lineno, token, value in stream: + if token in ignored_tokens: + continue + elif token == TOKEN_LINESTATEMENT_BEGIN: + token = TOKEN_BLOCK_BEGIN + elif token == TOKEN_LINESTATEMENT_END: + token = TOKEN_BLOCK_END + # we are not interested in those tokens in the parser + elif token in (TOKEN_RAW_BEGIN, TOKEN_RAW_END): + continue + elif token == TOKEN_DATA: + value = self._normalize_newlines(value) + elif token == "keyword": + token = value + elif token == TOKEN_NAME: + value = str(value) + if check_ident and not value.isidentifier(): + raise TemplateSyntaxError( + "Invalid character in identifier", lineno, name, filename + ) + elif token == TOKEN_STRING: + # try to unescape string + try: + value = ( + self._normalize_newlines(value[1:-1]) + .encode("ascii", "backslashreplace") + .decode("unicode-escape") + ) + except Exception as e: + msg = str(e).split(":")[-1].strip() + raise TemplateSyntaxError(msg, lineno, name, filename) + elif token == TOKEN_INTEGER: + value = int(value.replace("_", "")) + elif token == TOKEN_FLOAT: + # remove all "_" first to support more Python versions + value = literal_eval(value.replace("_", "")) + elif token == TOKEN_OPERATOR: + token = operators[value] + yield Token(lineno, token, value) + + def tokeniter(self, source, name, filename=None, state=None): + """This method tokenizes the text and returns the tokens in a + generator. Use this method if you just want to tokenize a template. + """ + source = text_type(source) + lines = source.splitlines() + if self.keep_trailing_newline and source: + for newline in ("\r\n", "\r", "\n"): + if source.endswith(newline): + lines.append("") + break + source = "\n".join(lines) + pos = 0 + lineno = 1 + stack = ["root"] + if state is not None and state != "root": + assert state in ("variable", "block"), "invalid state" + stack.append(state + "_begin") + statetokens = self.rules[stack[-1]] + source_length = len(source) + balancing_stack = [] + lstrip_unless_re = self.lstrip_unless_re + newlines_stripped = 0 + line_starting = True + + while 1: + # tokenizer loop + for regex, tokens, new_state in statetokens: + m = regex.match(source, pos) + # if no match we try again with the next rule + if m is None: + continue + + # we only match blocks and variables if braces / parentheses + # are balanced. continue parsing with the lower rule which + # is the operator rule. do this only if the end tags look + # like operators + if balancing_stack and tokens in ( + TOKEN_VARIABLE_END, + TOKEN_BLOCK_END, + TOKEN_LINESTATEMENT_END, + ): + continue + + # tuples support more options + if isinstance(tokens, tuple): + groups = m.groups() + + if isinstance(tokens, OptionalLStrip): + # Rule supports lstrip. Match will look like + # text, block type, whitespace control, type, control, ... + text = groups[0] + + # Skipping the text and first type, every other group is the + # whitespace control for each type. One of the groups will be + # -, +, or empty string instead of None. + strip_sign = next(g for g in groups[2::2] if g is not None) + + if strip_sign == "-": + # Strip all whitespace between the text and the tag. + stripped = text.rstrip() + newlines_stripped = text[len(stripped) :].count("\n") + groups = (stripped,) + groups[1:] + elif ( + # Not marked for preserving whitespace. + strip_sign != "+" + # lstrip is enabled. + and lstrip_unless_re is not None + # Not a variable expression. + and not m.groupdict().get(TOKEN_VARIABLE_BEGIN) + ): + # The start of text between the last newline and the tag. + l_pos = text.rfind("\n") + 1 + if l_pos > 0 or line_starting: + # If there's only whitespace between the newline and the + # tag, strip it. + if not lstrip_unless_re.search(text, l_pos): + groups = (text[:l_pos],) + groups[1:] + + for idx, token in enumerate(tokens): + # failure group + if token.__class__ is Failure: + raise token(lineno, filename) + # bygroup is a bit more complex, in that case we + # yield for the current token the first named + # group that matched + elif token == "#bygroup": + for key, value in iteritems(m.groupdict()): + if value is not None: + yield lineno, key, value + lineno += value.count("\n") + break + else: + raise RuntimeError( + "%r wanted to resolve " + "the token dynamically" + " but no group matched" % regex + ) + # normal group + else: + data = groups[idx] + if data or token not in ignore_if_empty: + yield lineno, token, data + lineno += data.count("\n") + newlines_stripped + newlines_stripped = 0 + + # strings as token just are yielded as it. + else: + data = m.group() + # update brace/parentheses balance + if tokens == TOKEN_OPERATOR: + if data == "{": + balancing_stack.append("}") + elif data == "(": + balancing_stack.append(")") + elif data == "[": + balancing_stack.append("]") + elif data in ("}", ")", "]"): + if not balancing_stack: + raise TemplateSyntaxError( + "unexpected '%s'" % data, lineno, name, filename + ) + expected_op = balancing_stack.pop() + if expected_op != data: + raise TemplateSyntaxError( + "unexpected '%s', " + "expected '%s'" % (data, expected_op), + lineno, + name, + filename, + ) + # yield items + if data or tokens not in ignore_if_empty: + yield lineno, tokens, data + lineno += data.count("\n") + + line_starting = m.group()[-1:] == "\n" + + # fetch new position into new variable so that we can check + # if there is a internal parsing error which would result + # in an infinite loop + pos2 = m.end() + + # handle state changes + if new_state is not None: + # remove the uppermost state + if new_state == "#pop": + stack.pop() + # resolve the new state by group checking + elif new_state == "#bygroup": + for key, value in iteritems(m.groupdict()): + if value is not None: + stack.append(key) + break + else: + raise RuntimeError( + "%r wanted to resolve the " + "new state dynamically but" + " no group matched" % regex + ) + # direct state name given + else: + stack.append(new_state) + statetokens = self.rules[stack[-1]] + # we are still at the same position and no stack change. + # this means a loop without break condition, avoid that and + # raise error + elif pos2 == pos: + raise RuntimeError( + "%r yielded empty string without stack change" % regex + ) + # publish new function and start again + pos = pos2 + break + # if loop terminated without break we haven't found a single match + # either we are at the end of the file or we have a problem + else: + # end of text + if pos >= source_length: + return + # something went wrong + raise TemplateSyntaxError( + "unexpected char %r at %d" % (source[pos], pos), + lineno, + name, + filename, + ) |