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- # -*- coding: utf-8 -*-
- #
- # Copyright (C) 2012 Ben Kurtovic <ben.kurtovic@verizon.net>
- #
- # Permission is hereby granted, free of charge, to any person obtaining a copy
- # of this software and associated documentation files (the "Software"), to deal
- # in the Software without restriction, including without limitation the rights
- # to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
- # copies of the Software, and to permit persons to whom the Software is
- # furnished to do so, subject to the following conditions:
- #
- # The above copyright notice and this permission notice shall be included in
- # all copies or substantial portions of the Software.
- #
- # THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
- # IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
- # FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
- # AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
- # LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
- # OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
- # SOFTWARE.
-
- from __future__ import unicode_literals
- from math import log
- import re
- import string
-
- from . import contexts
- from . import tokens
- from ..compat import htmlentities
-
- __all__ = ["Tokenizer"]
-
- class BadRoute(Exception):
- """Raised internally when the current tokenization route is invalid."""
- pass
-
-
- class Tokenizer(object):
- """Creates a list of tokens from a string of wikicode."""
- START = object()
- END = object()
- MARKERS = ["{", "}", "[", "]", "<", ">", "|", "=", "&", "#", "*", ";", ":",
- "/", "-", "\n", END]
- regex = re.compile(r"([{}\[\]<>|=&#*;:/\-\n])", flags=re.IGNORECASE)
-
- def __init__(self):
- self._text = None
- self._head = 0
- self._stacks = []
- self._global = 0
-
- @property
- def _stack(self):
- """The current token stack."""
- return self._stacks[-1][0]
-
- @property
- def _context(self):
- """The current token context."""
- return self._stacks[-1][1]
-
- @_context.setter
- def _context(self, value):
- self._stacks[-1][1] = value
-
- @property
- def _textbuffer(self):
- """The current textbuffer."""
- return self._stacks[-1][2]
-
- @_textbuffer.setter
- def _textbuffer(self, value):
- self._stacks[-1][2] = value
-
- def _push(self, context=0):
- """Add a new token stack, context, and textbuffer to the list."""
- self._stacks.append([[], context, []])
-
- def _push_textbuffer(self):
- """Push the textbuffer onto the stack as a Text node and clear it."""
- if self._textbuffer:
- self._stack.append(tokens.Text(text="".join(self._textbuffer)))
- self._textbuffer = []
-
- def _pop(self):
- """Pop the current stack/context/textbuffer, returing the stack."""
- self._push_textbuffer()
- return self._stacks.pop()[0]
-
- def _fail_route(self):
- """Fail the current tokenization route.
-
- Discards the current stack/context/textbuffer and raises
- :py:exc:`~.BadRoute`.
- """
- self._pop()
- raise BadRoute()
-
- def _write(self, token):
- """Write a token to the end of the current token stack."""
- self._push_textbuffer()
- self._stack.append(token)
-
- def _write_first(self, token):
- """Write a token to the beginning of the current token stack."""
- self._push_textbuffer()
- self._stack.insert(0, token)
-
- def _write_text(self, text):
- """Write text to the current textbuffer."""
- self._textbuffer.append(text)
-
- def _write_all(self, tokenlist):
- """Write a series of tokens to the current stack at once."""
- if tokenlist and isinstance(tokenlist[0], tokens.Text):
- self._write_text(tokenlist.pop(0).text)
- self._push_textbuffer()
- self._stack.extend(tokenlist)
-
- def _write_text_then_stack(self, text):
- """Pop the current stack, write *text*, and then write the stack."""
- stack = self._pop()
- self._write_text(text)
- if stack:
- self._write_all(stack)
- self._head -= 1
-
- def _read(self, delta=0, wrap=False, strict=False):
- """Read the value at a relative point in the wikicode.
-
- The value is read from :py:attr:`self._head <_head>` plus the value of
- *delta* (which can be negative). If *wrap* is ``False``, we will not
- allow attempts to read from the end of the string if ``self._head +
- delta`` is negative. If *strict* is ``True``, the route will be failed
- (with :py:meth:`_fail_route`) if we try to read from past the end of
- the string; otherwise, :py:attr:`self.END <END>` is returned. If we try
- to read from before the start of the string, :py:attr:`self.START
- <START>` is returned.
- """
- index = self._head + delta
- if index < 0 and (not wrap or abs(index) > len(self._text)):
- return self.START
- try:
- return self._text[index]
- except IndexError:
- if strict:
- self._fail_route()
- return self.END
-
- def _parse_template_or_argument(self):
- """Parse a template or argument at the head of the wikicode string."""
- self._head += 2
- braces = 2
- while self._read() == "{":
- braces += 1
- self._head += 1
- self._push()
-
- while braces:
- if braces == 1:
- return self._write_text_then_stack("{")
- if braces == 2:
- try:
- self._parse_template()
- except BadRoute:
- return self._write_text_then_stack("{{")
- break
- try:
- self._parse_argument()
- braces -= 3
- except BadRoute:
- try:
- self._parse_template()
- braces -= 2
- except BadRoute:
- return self._write_text_then_stack("{" * braces)
- if braces:
- self._head += 1
-
- self._write_all(self._pop())
-
- def _parse_template(self):
- """Parse a template at the head of the wikicode string."""
- reset = self._head
- try:
- template = self._parse(contexts.TEMPLATE_NAME)
- except BadRoute:
- self._head = reset
- raise
- else:
- self._write_first(tokens.TemplateOpen())
- self._write_all(template)
- self._write(tokens.TemplateClose())
-
- def _parse_argument(self):
- """Parse an argument at the head of the wikicode string."""
- reset = self._head
- try:
- argument = self._parse(contexts.ARGUMENT_NAME)
- except BadRoute:
- self._head = reset
- raise
- else:
- self._write_first(tokens.ArgumentOpen())
- self._write_all(argument)
- self._write(tokens.ArgumentClose())
-
- def _verify_safe(self, unsafes):
- """Verify that there are no unsafe characters in the current stack.
-
- The route will be failed if the name contains any element of *unsafes*
- in it (not merely at the beginning or end). This is used when parsing a
- template name or parameter key, which cannot contain newlines.
- """
- self._push_textbuffer()
- if self._stack:
- text = [tok for tok in self._stack if isinstance(tok, tokens.Text)]
- text = "".join([token.text for token in text]).strip()
- if text and any([unsafe in text for unsafe in unsafes]):
- self._fail_route()
-
- def _handle_template_param(self):
- """Handle a template parameter at the head of the string."""
- if self._context & contexts.TEMPLATE_NAME:
- self._verify_safe(["\n", "{", "}", "[", "]"])
- self._context ^= contexts.TEMPLATE_NAME
- if self._context & contexts.TEMPLATE_PARAM_VALUE:
- self._context ^= contexts.TEMPLATE_PARAM_VALUE
- self._context |= contexts.TEMPLATE_PARAM_KEY
- self._write(tokens.TemplateParamSeparator())
-
- def _handle_template_param_value(self):
- """Handle a template parameter's value at the head of the string."""
- self._verify_safe(["\n", "{{", "}}"])
- self._context ^= contexts.TEMPLATE_PARAM_KEY
- self._context |= contexts.TEMPLATE_PARAM_VALUE
- self._write(tokens.TemplateParamEquals())
-
- def _handle_template_end(self):
- """Handle the end of a template at the head of the string."""
- if self._context & contexts.TEMPLATE_NAME:
- self._verify_safe(["\n", "{", "}", "[", "]"])
- self._head += 1
- return self._pop()
-
- def _handle_argument_separator(self):
- """Handle the separator between an argument's name and default."""
- self._verify_safe(["\n", "{{", "}}"])
- self._context ^= contexts.ARGUMENT_NAME
- self._context |= contexts.ARGUMENT_DEFAULT
- self._write(tokens.ArgumentSeparator())
-
- def _handle_argument_end(self):
- """Handle the end of an argument at the head of the string."""
- if self._context & contexts.ARGUMENT_NAME:
- self._verify_safe(["\n", "{{", "}}"])
- self._head += 2
- return self._pop()
-
- def _parse_heading(self):
- """Parse a section heading at the head of the wikicode string."""
- self._global |= contexts.GL_HEADING
- reset = self._head
- self._head += 1
- best = 1
- while self._read() == "=":
- best += 1
- self._head += 1
- context = contexts.HEADING_LEVEL_1 << min(best - 1, 5)
-
- try:
- title, level = self._parse(context)
- except BadRoute:
- self._head = reset + best - 1
- self._write_text("=" * best)
- else:
- self._write(tokens.HeadingStart(level=level))
- if level < best:
- self._write_text("=" * (best - level))
- self._write_all(title)
- self._write(tokens.HeadingEnd())
- finally:
- self._global ^= contexts.GL_HEADING
-
- def _handle_heading_end(self):
- """Handle the end of a section heading at the head of the string."""
- reset = self._head
- self._head += 1
- best = 1
- while self._read() == "=":
- best += 1
- self._head += 1
- current = int(log(self._context / contexts.HEADING_LEVEL_1, 2)) + 1
- level = min(current, min(best, 6))
-
- try:
- after, after_level = self._parse(self._context)
- except BadRoute:
- if level < best:
- self._write_text("=" * (best - level))
- self._head = reset + best - 1
- return self._pop(), level
- else:
- self._write_text("=" * best)
- self._write_all(after)
- return self._pop(), after_level
-
- def _really_parse_entity(self):
- """Actually parse a HTML entity and ensure that it is valid."""
- self._write(tokens.HTMLEntityStart())
- self._head += 1
-
- this = self._read(strict=True)
- if this == "#":
- numeric = True
- self._write(tokens.HTMLEntityNumeric())
- self._head += 1
- this = self._read(strict=True)
- if this[0].lower() == "x":
- hexadecimal = True
- self._write(tokens.HTMLEntityHex(char=this[0]))
- this = this[1:]
- if not this:
- self._fail_route()
- else:
- hexadecimal = False
- else:
- numeric = hexadecimal = False
-
- valid = string.hexdigits if hexadecimal else string.digits
- if not numeric and not hexadecimal:
- valid += string.ascii_letters
- if not all([char in valid for char in this]):
- self._fail_route()
-
- self._head += 1
- if self._read() != ";":
- self._fail_route()
- if numeric:
- test = int(this, 16) if hexadecimal else int(this)
- if test < 1 or test > 0x10FFFF:
- self._fail_route()
- else:
- if this not in htmlentities.entitydefs:
- self._fail_route()
-
- self._write(tokens.Text(text=this))
- self._write(tokens.HTMLEntityEnd())
-
- def _parse_entity(self):
- """Parse a HTML entity at the head of the wikicode string."""
- reset = self._head
- self._push()
- try:
- self._really_parse_entity()
- except BadRoute:
- self._head = reset
- self._write_text(self._read())
- else:
- self._write_all(self._pop())
-
- def _parse(self, context=0):
- """Parse the wikicode string, using *context* for when to stop."""
- self._push(context)
- while True:
- this = self._read()
- if this not in self.MARKERS:
- self._write_text(this)
- self._head += 1
- continue
- if this is self.END:
- fail = contexts.TEMPLATE | contexts.ARGUMENT | contexts.HEADING
- if self._context & fail:
- self._fail_route()
- return self._pop()
- next = self._read(1)
- if this == next == "{":
- self._parse_template_or_argument()
- elif this == "|" and self._context & contexts.TEMPLATE:
- self._handle_template_param()
- elif this == "=" and self._context & contexts.TEMPLATE_PARAM_KEY:
- self._handle_template_param_value()
- elif this == next == "}" and self._context & contexts.TEMPLATE:
- return self._handle_template_end()
- elif this == "|" and self._context & contexts.ARGUMENT_NAME:
- self._handle_argument_separator()
- elif this == next == "}" and self._context & contexts.ARGUMENT:
- if self._read(2) == "}":
- return self._handle_argument_end()
- else:
- self._write_text("}")
- elif this == "=" and not self._global & contexts.GL_HEADING:
- if self._read(-1) in ("\n", self.START):
- self._parse_heading()
- else:
- self._write_text("=")
- elif this == "=" and self._context & contexts.HEADING:
- return self._handle_heading_end()
- elif this == "\n" and self._context & contexts.HEADING:
- self._fail_route()
- elif this == "&":
- self._parse_entity()
- else:
- self._write_text(this)
- self._head += 1
-
- def tokenize(self, text):
- """Build a list of tokens from a string of wikicode and return it."""
- split = self.regex.split(text)
- self._text = [segment for segment in split if segment]
- return self._parse()
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