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#!/usr/bin/env python
# -*- coding: utf-8 -*-
"""New CSS Tokenizer (a generator)
"""
__all__ = ['Tokenizer', 'CSSProductions']
__docformat__ = 'restructuredtext'
__version__ = '$Id$'
from cssproductions import *
from helper import normalize
import itertools
import re
import sys
_TOKENIZER_CACHE = {}
class Tokenizer(object):
"""
generates a list of Token tuples:
(Tokenname, value, startline, startcolumn)
"""
_atkeywords = {
u'@font-face': CSSProductions.FONT_FACE_SYM,
u'@import': CSSProductions.IMPORT_SYM,
u'@media': CSSProductions.MEDIA_SYM,
u'@namespace': CSSProductions.NAMESPACE_SYM,
u'@page': CSSProductions.PAGE_SYM,
u'@variables': CSSProductions.VARIABLES_SYM
}
_linesep = u'\n'
unicodesub = re.compile(r'\\[0-9a-fA-F]{1,6}(?:\r\n|[\t\r\n\f\x20])?').sub
cleanstring = re.compile(r'\\((\r\n)|[\n\r\f])').sub
def __init__(self, macros=None, productions=None, doComments=True):
"""
inits tokenizer with given macros and productions which default to
cssutils own macros and productions
"""
if isinstance(macros, dict):
macros_hash_key = sorted(macros.items())
else:
macros_hash_key = macros
hash_key = str((macros_hash_key, productions))
if hash_key in _TOKENIZER_CACHE:
(tokenmatches, commentmatcher, urimatcher) = _TOKENIZER_CACHE[hash_key]
else:
if not macros:
macros = MACROS
if not productions:
productions = PRODUCTIONS
tokenmatches = self._compile_productions(self._expand_macros(macros,
productions))
commentmatcher = [x[1] for x in tokenmatches if x[0] == 'COMMENT'][0]
urimatcher = [x[1] for x in tokenmatches if x[0] == 'URI'][0]
_TOKENIZER_CACHE[hash_key] = (tokenmatches, commentmatcher, urimatcher)
self.tokenmatches = tokenmatches
self.commentmatcher = commentmatcher
self.urimatcher = urimatcher
self._doComments = doComments
self._pushed = []
def _expand_macros(self, macros, productions):
"""returns macro expanded productions, order of productions is kept"""
def macro_value(m):
return '(?:%s)' % macros[m.groupdict()['macro']]
expanded = []
for key, value in productions:
while re.search(r'{[a-zA-Z][a-zA-Z0-9-]*}', value):
value = re.sub(r'{(?P<macro>[a-zA-Z][a-zA-Z0-9-]*)}',
macro_value, value)
expanded.append((key, value))
return expanded
def _compile_productions(self, expanded_productions):
"""compile productions into callable match objects, order is kept"""
compiled = []
for key, value in expanded_productions:
compiled.append((key, re.compile('^(?:%s)' % value, re.U).match))
return compiled
def push(self, *tokens):
"""Push back tokens which have been pulled but not processed."""
self._pushed = itertools.chain(tokens, self._pushed)
def clear(self):
self._pushed = []
def tokenize(self, text, fullsheet=False):
"""Generator: Tokenize text and yield tokens, each token is a tuple
of::
(name, value, line, col)
The token value will contain a normal string, meaning CSS unicode
escapes have been resolved to normal characters. The serializer
escapes needed characters back to unicode escapes depending on
the stylesheet target encoding.
text
to be tokenized
fullsheet
if ``True`` appends EOF token as last one and completes incomplete
COMMENT or INVALID (to STRING) tokens
"""
def _repl(m):
"used by unicodesub"
num = int(m.group(0)[1:], 16)
if num <= sys.maxunicode:
return unichr(num)
else:
return m.group(0)
def _normalize(value):
"normalize and do unicodesub"
return normalize(self.unicodesub(_repl, value))
line = col = 1
# check for BOM first as it should only be max one at the start
(BOM, matcher), productions = self.tokenmatches[0], self.tokenmatches[1:]
match = matcher(text)
if match:
found = match.group(0)
yield (BOM, found, line, col)
text = text[len(found):]
# check for @charset which is valid only at start of CSS
if text.startswith('@charset '):
found = '@charset ' # production has trailing S!
yield (CSSProductions.CHARSET_SYM, found, line, col)
text = text[len(found):]
col += len(found)
while text:
# do pushed tokens before new ones
for pushed in self._pushed:
yield pushed
# speed test for most used CHARs, sadly . not possible :(
c = text[0]
if c in u',:;{}>+[]':
yield ('CHAR', c, line, col)
col += 1
text = text[1:]
else:
# check all other productions, at least CHAR must match
for name, matcher in productions:
# TODO: USE bad comment?
if fullsheet and name == 'CHAR' and text.startswith(u'/*'):
# before CHAR production test for incomplete comment
possiblecomment = u'%s*/' % text
match = self.commentmatcher(possiblecomment)
if match and self._doComments:
yield ('COMMENT', possiblecomment, line, col)
text = None # ate all remaining text
break
match = matcher(text) # if no match try next production
if match:
found = match.group(0) # needed later for line/col
if fullsheet:
# check if found may be completed into a full token
if 'INVALID' == name and text == found:
# complete INVALID to STRING with start char " or '
name, found = 'STRING', '%s%s' % (found, found[0])
elif 'FUNCTION' == name and\
u'url(' == _normalize(found):
# url( is a FUNCTION if incomplete sheet
# FUNCTION production MUST BE after URI production
for end in (u"')", u'")', u')'):
possibleuri = '%s%s' % (text, end)
match = self.urimatcher(possibleuri)
if match:
name, found = 'URI', match.group(0)
break
if name in ('DIMENSION', 'IDENT', 'STRING', 'URI',
'HASH', 'COMMENT', 'FUNCTION', 'INVALID',
'UNICODE-RANGE'):
# may contain unicode escape, replace with normal
# char but do not _normalize (?)
value = self.unicodesub(_repl, found)
if name in ('STRING', 'INVALID'): #'URI'?
# remove \ followed by nl (so escaped) from string
value = self.cleanstring('', value)
else:
if 'ATKEYWORD' == name:
try:
# get actual ATKEYWORD SYM
name = self._atkeywords[_normalize(found)]
except KeyError, e:
# might also be misplace @charset...
if '@charset' == found and u' ' == text[len(found):len(found)+1]:
# @charset needs tailing S!
name = CSSProductions.CHARSET_SYM
found += u' '
else:
name = 'ATKEYWORD'
value = found # should not contain unicode escape (?)
if self._doComments or (not self._doComments and
name != 'COMMENT'):
yield (name, value, line, col)
text = text[len(found):]
nls = found.count(self._linesep)
line += nls
if nls:
col = len(found[found.rfind(self._linesep):])
else:
col += len(found)
break
if fullsheet:
yield ('EOF', u'', line, col)