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bazarr/libs/soupsieve/css_parser.py
Louis Vézina c5fa0f56e4 WIP
2019-09-13 15:14:31 -04:00

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"""CSS selector parser."""
from __future__ import unicode_literals
import re
from . import util
from . import css_match as cm
from . import css_types as ct
from .util import SelectorSyntaxError
UNICODE_REPLACEMENT_CHAR = 0xFFFD
# Simple pseudo classes that take no parameters
PSEUDO_SIMPLE = {
":any-link",
":empty",
":first-child",
":first-of-type",
":in-range",
":out-of-range",
":last-child",
":last-of-type",
":link",
":only-child",
":only-of-type",
":root",
':checked',
':default',
':disabled',
':enabled',
':indeterminate',
':optional',
':placeholder-shown',
':read-only',
':read-write',
':required',
':scope',
':defined'
}
# Supported, simple pseudo classes that match nothing in the Soup Sieve environment
PSEUDO_SIMPLE_NO_MATCH = {
':active',
':current',
':focus',
':focus-visible',
':focus-within',
':future',
':host',
':hover',
':local-link',
':past',
':paused',
':playing',
':target',
':target-within',
':user-invalid',
':visited'
}
# Complex pseudo classes that take selector lists
PSEUDO_COMPLEX = {
':contains',
':has',
':is',
':matches',
':not',
':where'
}
PSEUDO_COMPLEX_NO_MATCH = {
':current',
':host',
':host-context'
}
# Complex pseudo classes that take very specific parameters and are handled special
PSEUDO_SPECIAL = {
':dir',
':lang',
':nth-child',
':nth-last-child',
':nth-last-of-type',
':nth-of-type'
}
PSEUDO_SUPPORTED = PSEUDO_SIMPLE | PSEUDO_SIMPLE_NO_MATCH | PSEUDO_COMPLEX | PSEUDO_COMPLEX_NO_MATCH | PSEUDO_SPECIAL
# Sub-patterns parts
# Whitespace
NEWLINE = r'(?:\r\n|(?!\r\n)[\n\f\r])'
WS = r'(?:[ \t]|{})'.format(NEWLINE)
# Comments
COMMENTS = r'(?:/\*[^*]*\*+(?:[^/*][^*]*\*+)*/)'
# Whitespace with comments included
WSC = r'(?:{ws}|{comments})'.format(ws=WS, comments=COMMENTS)
# CSS escapes
CSS_ESCAPES = r'(?:\\(?:[a-f0-9]{{1,6}}{ws}?|[^\r\n\f]|$))'.format(ws=WS)
CSS_STRING_ESCAPES = r'(?:\\(?:[a-f0-9]{{1,6}}{ws}?|[^\r\n\f]|$|{nl}))'.format(ws=WS, nl=NEWLINE)
# CSS Identifier
IDENTIFIER = r'''
(?:(?:-?(?:[^\x00-\x2f\x30-\x40\x5B-\x5E\x60\x7B-\x9f]|{esc})+|--)
(?:[^\x00-\x2c\x2e\x2f\x3A-\x40\x5B-\x5E\x60\x7B-\x9f]|{esc})*)
'''.format(esc=CSS_ESCAPES)
# `nth` content
NTH = r'(?:[-+])?(?:[0-9]+n?|n)(?:(?<=n){ws}*(?:[-+]){ws}*(?:[0-9]+))?'.format(ws=WSC)
# Value: quoted string or identifier
VALUE = r'''
(?:"(?:\\(?:.|{nl})|[^\\"\r\n\f]+)*?"|'(?:\\(?:.|{nl})|[^\\'\r\n\f]+)*?'|{ident}+)
'''.format(nl=NEWLINE, ident=IDENTIFIER)
# Attribute value comparison. `!=` is handled special as it is non-standard.
ATTR = r'''
(?:{ws}*(?P<cmp>[!~^|*$]?=){ws}*(?P<value>{value})(?:{ws}+(?P<case>[is]))?)?{ws}*\]
'''.format(ws=WSC, value=VALUE)
# Selector patterns
# IDs (`#id`)
PAT_ID = r'\#{ident}'.format(ident=IDENTIFIER)
# Classes (`.class`)
PAT_CLASS = r'\.{ident}'.format(ident=IDENTIFIER)
# Prefix:Tag (`prefix|tag`)
PAT_TAG = r'(?:(?:{ident}|\*)?\|)?(?:{ident}|\*)'.format(ident=IDENTIFIER)
# Attributes (`[attr]`, `[attr=value]`, etc.)
PAT_ATTR = r'\[{ws}*(?P<ns_attr>(?:(?:{ident}|\*)?\|)?{ident}){attr}'.format(ws=WSC, ident=IDENTIFIER, attr=ATTR)
# Pseudo class (`:pseudo-class`, `:pseudo-class(`)
PAT_PSEUDO_CLASS = r'(?P<name>:{ident})(?P<open>\({ws}*)?'.format(ws=WSC, ident=IDENTIFIER)
# Pseudo class special patterns. Matches `:pseudo-class(` for special case pseudo classes.
PAT_PSEUDO_CLASS_SPECIAL = r'(?P<name>:{ident})(?P<open>\({ws}*)'.format(ws=WSC, ident=IDENTIFIER)
# Custom pseudo class (`:--custom-pseudo`)
PAT_PSEUDO_CLASS_CUSTOM = r'(?P<name>:(?=--){ident})'.format(ident=IDENTIFIER)
# Closing pseudo group (`)`)
PAT_PSEUDO_CLOSE = r'{ws}*\)'.format(ws=WSC)
# Pseudo element (`::pseudo-element`)
PAT_PSEUDO_ELEMENT = r':{}'.format(PAT_PSEUDO_CLASS)
# At rule (`@page`, etc.) (not supported)
PAT_AT_RULE = r'@P{ident}'.format(ident=IDENTIFIER)
# Pseudo class `nth-child` (`:nth-child(an+b [of S]?)`, `:first-child`, etc.)
PAT_PSEUDO_NTH_CHILD = r'''
(?P<pseudo_nth_child>{name}
(?P<nth_child>{nth}|even|odd))(?:{wsc}*\)|(?P<of>{comments}*{ws}{wsc}*of{comments}*{ws}{wsc}*))
'''.format(name=PAT_PSEUDO_CLASS_SPECIAL, wsc=WSC, comments=COMMENTS, ws=WS, nth=NTH)
# Pseudo class `nth-of-type` (`:nth-of-type(an+b)`, `:first-of-type`, etc.)
PAT_PSEUDO_NTH_TYPE = r'''
(?P<pseudo_nth_type>{name}
(?P<nth_type>{nth}|even|odd)){ws}*\)
'''.format(name=PAT_PSEUDO_CLASS_SPECIAL, ws=WSC, nth=NTH)
# Pseudo class language (`:lang("*-de", en)`)
PAT_PSEUDO_LANG = r'{name}(?P<values>{value}(?:{ws}*,{ws}*{value})*){ws}*\)'.format(
name=PAT_PSEUDO_CLASS_SPECIAL, ws=WSC, value=VALUE
)
# Pseudo class direction (`:dir(ltr)`)
PAT_PSEUDO_DIR = r'{name}(?P<dir>ltr|rtl){ws}*\)'.format(name=PAT_PSEUDO_CLASS_SPECIAL, ws=WSC)
# Combining characters (`>`, `~`, ` `, `+`, `,`)
PAT_COMBINE = r'{wsc}*?(?P<relation>[,+>~]|{ws}(?![,+>~])){wsc}*'.format(ws=WS, wsc=WSC)
# Extra: Contains (`:contains(text)`)
PAT_PSEUDO_CONTAINS = r'{name}(?P<values>{value}(?:{ws}*,{ws}*{value})*){ws}*\)'.format(
name=PAT_PSEUDO_CLASS_SPECIAL, ws=WSC, value=VALUE
)
# Regular expressions
# CSS escape pattern
RE_CSS_ESC = re.compile(r'(?:(\\[a-f0-9]{{1,6}}{ws}?)|(\\[^\r\n\f])|(\\$))'.format(ws=WSC), re.I)
RE_CSS_STR_ESC = re.compile(
r'(?:(\\[a-f0-9]{{1,6}}{ws}?)|(\\[^\r\n\f])|(\\$)|(\\{nl}))'.format(ws=WS, nl=NEWLINE), re.I
)
# Pattern to break up `nth` specifiers
RE_NTH = re.compile(
r'(?P<s1>[-+])?(?P<a>[0-9]+n?|n)(?:(?<=n){ws}*(?P<s2>[-+]){ws}*(?P<b>[0-9]+))?'.format(ws=WSC),
re.I
)
# Pattern to iterate multiple values.
RE_VALUES = re.compile(r'(?:(?P<value>{value})|(?P<split>{ws}*,{ws}*))'.format(ws=WSC, value=VALUE), re.X)
# Whitespace checks
RE_WS = re.compile(WS)
RE_WS_BEGIN = re.compile('^{}*'.format(WSC))
RE_WS_END = re.compile('{}*$'.format(WSC))
RE_CUSTOM = re.compile(r'^{}$'.format(PAT_PSEUDO_CLASS_CUSTOM), re.X)
# Constants
# List split token
COMMA_COMBINATOR = ','
# Relation token for descendant
WS_COMBINATOR = " "
# Parse flags
FLG_PSEUDO = 0x01
FLG_NOT = 0x02
FLG_RELATIVE = 0x04
FLG_DEFAULT = 0x08
FLG_HTML = 0x10
FLG_INDETERMINATE = 0x20
FLG_OPEN = 0x40
FLG_IN_RANGE = 0x80
FLG_OUT_OF_RANGE = 0x100
# Maximum cached patterns to store
_MAXCACHE = 500
@util.lru_cache(maxsize=_MAXCACHE)
def _cached_css_compile(pattern, namespaces, custom, flags):
"""Cached CSS compile."""
custom_selectors = process_custom(custom)
return cm.SoupSieve(
pattern,
CSSParser(pattern, custom=custom_selectors, flags=flags).process_selectors(),
namespaces,
custom,
flags
)
def _purge_cache():
"""Purge the cache."""
_cached_css_compile.cache_clear()
def process_custom(custom):
"""Process custom."""
custom_selectors = {}
if custom is not None:
for key, value in custom.items():
name = util.lower(key)
if RE_CUSTOM.match(name) is None:
raise SelectorSyntaxError("The name '{}' is not a valid custom pseudo-class name".format(name))
if name in custom_selectors:
raise KeyError("The custom selector '{}' has already been registered".format(name))
custom_selectors[css_unescape(name)] = value
return custom_selectors
def css_unescape(content, string=False):
"""
Unescape CSS value.
Strings allow for spanning the value on multiple strings by escaping a new line.
"""
def replace(m):
"""Replace with the appropriate substitute."""
if m.group(1):
codepoint = int(m.group(1)[1:], 16)
if codepoint == 0:
codepoint = UNICODE_REPLACEMENT_CHAR
value = util.uchr(codepoint)
elif m.group(2):
value = m.group(2)[1:]
elif m.group(3):
value = '\ufffd'
else:
value = ''
return value
return (RE_CSS_ESC if not string else RE_CSS_STR_ESC).sub(replace, content)
def escape(ident):
"""Escape identifier."""
string = []
length = len(ident)
start_dash = length > 0 and ident[0] == '-'
if length == 1 and start_dash:
# Need to escape identifier that is a single `-` with no other characters
string.append('\\{}'.format(ident))
else:
for index, c in enumerate(ident):
codepoint = util.uord(c)
if codepoint == 0x00:
string.append('\ufffd')
elif (0x01 <= codepoint <= 0x1F) or codepoint == 0x7F:
string.append('\\{:x} '.format(codepoint))
elif (index == 0 or (start_dash and index == 1)) and (0x30 <= codepoint <= 0x39):
string.append('\\{:x} '.format(codepoint))
elif (
codepoint in (0x2D, 0x5F) or codepoint >= 0x80 or (0x30 <= codepoint <= 0x39) or
(0x30 <= codepoint <= 0x39) or (0x41 <= codepoint <= 0x5A) or (0x61 <= codepoint <= 0x7A)
):
string.append(c)
else:
string.append('\\{}'.format(c))
return ''.join(string)
class SelectorPattern(object):
"""Selector pattern."""
def __init__(self, name, pattern):
"""Initialize."""
self.name = name
self.re_pattern = re.compile(pattern, re.I | re.X | re.U)
def get_name(self):
"""Get name."""
return self.name
def enabled(self, flags):
"""Enabled."""
return True
def match(self, selector, index):
"""Match the selector."""
return self.re_pattern.match(selector, index)
class SpecialPseudoPattern(SelectorPattern):
"""Selector pattern."""
def __init__(self, patterns):
"""Initialize."""
self.patterns = {}
for p in patterns:
name = p[0]
pattern = SelectorPattern(name, p[2])
for pseudo in p[1]:
self.patterns[pseudo] = pattern
self.matched_name = None
self.re_pseudo_name = re.compile(PAT_PSEUDO_CLASS_SPECIAL, re.I | re.X | re.U)
def get_name(self):
"""Get name."""
return self.matched_name.get_name()
def enabled(self, flags):
"""Enabled."""
return True
def match(self, selector, index):
"""Match the selector."""
pseudo = None
m = self.re_pseudo_name.match(selector, index)
if m:
name = util.lower(css_unescape(m.group('name')))
pattern = self.patterns.get(name)
if pattern:
pseudo = pattern.match(selector, index)
if pseudo:
self.matched_name = pattern
return pseudo
class _Selector(object):
"""
Intermediate selector class.
This stores selector data for a compound selector as we are acquiring them.
Once we are done collecting the data for a compound selector, we freeze
the data in an object that can be pickled and hashed.
"""
def __init__(self, **kwargs):
"""Initialize."""
self.tag = kwargs.get('tag', None)
self.ids = kwargs.get('ids', [])
self.classes = kwargs.get('classes', [])
self.attributes = kwargs.get('attributes', [])
self.nth = kwargs.get('nth', [])
self.selectors = kwargs.get('selectors', [])
self.relations = kwargs.get('relations', [])
self.rel_type = kwargs.get('rel_type', None)
self.contains = kwargs.get('contains', [])
self.lang = kwargs.get('lang', [])
self.flags = kwargs.get('flags', 0)
self.no_match = kwargs.get('no_match', False)
def _freeze_relations(self, relations):
"""Freeze relation."""
if relations:
sel = relations[0]
sel.relations.extend(relations[1:])
return ct.SelectorList([sel.freeze()])
else:
return ct.SelectorList()
def freeze(self):
"""Freeze self."""
if self.no_match:
return ct.SelectorNull()
else:
return ct.Selector(
self.tag,
tuple(self.ids),
tuple(self.classes),
tuple(self.attributes),
tuple(self.nth),
tuple(self.selectors),
self._freeze_relations(self.relations),
self.rel_type,
tuple(self.contains),
tuple(self.lang),
self.flags
)
def __str__(self): # pragma: no cover
"""String representation."""
return (
'_Selector(tag={!r}, ids={!r}, classes={!r}, attributes={!r}, nth={!r}, selectors={!r}, '
'relations={!r}, rel_type={!r}, contains={!r}, lang={!r}, flags={!r}, no_match={!r})'
).format(
self.tag, self.ids, self.classes, self.attributes, self.nth, self.selectors,
self.relations, self.rel_type, self.contains, self.lang, self.flags, self.no_match
)
__repr__ = __str__
class CSSParser(object):
"""Parse CSS selectors."""
css_tokens = (
SelectorPattern("pseudo_close", PAT_PSEUDO_CLOSE),
SpecialPseudoPattern(
(
("pseudo_contains", (':contains',), PAT_PSEUDO_CONTAINS),
("pseudo_nth_child", (':nth-child', ':nth-last-child'), PAT_PSEUDO_NTH_CHILD),
("pseudo_nth_type", (':nth-of-type', ':nth-last-of-type'), PAT_PSEUDO_NTH_TYPE),
("pseudo_lang", (':lang',), PAT_PSEUDO_LANG),
("pseudo_dir", (':dir',), PAT_PSEUDO_DIR)
)
),
SelectorPattern("pseudo_class_custom", PAT_PSEUDO_CLASS_CUSTOM),
SelectorPattern("pseudo_class", PAT_PSEUDO_CLASS),
SelectorPattern("pseudo_element", PAT_PSEUDO_ELEMENT),
SelectorPattern("at_rule", PAT_AT_RULE),
SelectorPattern("id", PAT_ID),
SelectorPattern("class", PAT_CLASS),
SelectorPattern("tag", PAT_TAG),
SelectorPattern("attribute", PAT_ATTR),
SelectorPattern("combine", PAT_COMBINE)
)
def __init__(self, selector, custom=None, flags=0):
"""Initialize."""
self.pattern = selector.replace('\x00', '\ufffd')
self.flags = flags
self.debug = self.flags & util.DEBUG
self.custom = {} if custom is None else custom
def parse_attribute_selector(self, sel, m, has_selector):
"""Create attribute selector from the returned regex match."""
inverse = False
op = m.group('cmp')
case = util.lower(m.group('case')) if m.group('case') else None
parts = [css_unescape(a) for a in m.group('ns_attr').split('|')]
ns = ''
is_type = False
pattern2 = None
if len(parts) > 1:
ns = parts[0]
attr = parts[1]
else:
attr = parts[0]
if case:
flags = re.I if case == 'i' else 0
elif util.lower(attr) == 'type':
flags = re.I
is_type = True
else:
flags = 0
if op:
if m.group('value').startswith(('"', "'")):
value = css_unescape(m.group('value')[1:-1], True)
else:
value = css_unescape(m.group('value'))
else:
value = None
if not op:
# Attribute name
pattern = None
elif op.startswith('^'):
# Value start with
pattern = re.compile(r'^%s.*' % re.escape(value), flags)
elif op.startswith('$'):
# Value ends with
pattern = re.compile(r'.*?%s$' % re.escape(value), flags)
elif op.startswith('*'):
# Value contains
pattern = re.compile(r'.*?%s.*' % re.escape(value), flags)
elif op.startswith('~'):
# Value contains word within space separated list
# `~=` should match nothing if it is empty or contains whitespace,
# so if either of these cases is present, use `[^\s\S]` which cannot be matched.
value = r'[^\s\S]' if not value or RE_WS.search(value) else re.escape(value)
pattern = re.compile(r'.*?(?:(?<=^)|(?<=[ \t\r\n\f]))%s(?=(?:[ \t\r\n\f]|$)).*' % value, flags)
elif op.startswith('|'):
# Value starts with word in dash separated list
pattern = re.compile(r'^%s(?:-.*)?$' % re.escape(value), flags)
else:
# Value matches
pattern = re.compile(r'^%s$' % re.escape(value), flags)
if op.startswith('!'):
# Equivalent to `:not([attr=value])`
inverse = True
if is_type and pattern:
pattern2 = re.compile(pattern.pattern)
# Append the attribute selector
sel_attr = ct.SelectorAttribute(attr, ns, pattern, pattern2)
if inverse:
# If we are using `!=`, we need to nest the pattern under a `:not()`.
sub_sel = _Selector()
sub_sel.attributes.append(sel_attr)
not_list = ct.SelectorList([sub_sel.freeze()], True, False)
sel.selectors.append(not_list)
else:
sel.attributes.append(sel_attr)
has_selector = True
return has_selector
def parse_tag_pattern(self, sel, m, has_selector):
"""Parse tag pattern from regex match."""
parts = [css_unescape(x) for x in m.group(0).split('|')]
if len(parts) > 1:
prefix = parts[0]
tag = parts[1]
else:
tag = parts[0]
prefix = None
sel.tag = ct.SelectorTag(tag, prefix)
has_selector = True
return has_selector
def parse_pseudo_class_custom(self, sel, m, has_selector):
"""
Parse custom pseudo class alias.
Compile custom selectors as we need them. When compiling a custom selector,
set it to `None` in the dictionary so we can avoid an infinite loop.
"""
pseudo = util.lower(css_unescape(m.group('name')))
selector = self.custom.get(pseudo)
if selector is None:
raise SelectorSyntaxError(
"Undefined custom selector '{}' found at postion {}".format(pseudo, m.end(0)),
self.pattern,
m.end(0)
)
if not isinstance(selector, ct.SelectorList):
self.custom[pseudo] = None
selector = CSSParser(
selector, custom=self.custom, flags=self.flags
).process_selectors(flags=FLG_PSEUDO)
self.custom[pseudo] = selector
sel.selectors.append(selector)
has_selector = True
return has_selector
def parse_pseudo_class(self, sel, m, has_selector, iselector, is_html):
"""Parse pseudo class."""
complex_pseudo = False
pseudo = util.lower(css_unescape(m.group('name')))
if m.group('open'):
complex_pseudo = True
if complex_pseudo and pseudo in PSEUDO_COMPLEX:
has_selector = self.parse_pseudo_open(sel, pseudo, has_selector, iselector, m.end(0))
elif not complex_pseudo and pseudo in PSEUDO_SIMPLE:
if pseudo == ':root':
sel.flags |= ct.SEL_ROOT
elif pseudo == ':defined':
sel.flags |= ct.SEL_DEFINED
is_html = True
elif pseudo == ':scope':
sel.flags |= ct.SEL_SCOPE
elif pseudo == ':empty':
sel.flags |= ct.SEL_EMPTY
elif pseudo in (':link', ':any-link'):
sel.selectors.append(CSS_LINK)
elif pseudo == ':checked':
sel.selectors.append(CSS_CHECKED)
elif pseudo == ':default':
sel.selectors.append(CSS_DEFAULT)
elif pseudo == ':indeterminate':
sel.selectors.append(CSS_INDETERMINATE)
elif pseudo == ":disabled":
sel.selectors.append(CSS_DISABLED)
elif pseudo == ":enabled":
sel.selectors.append(CSS_ENABLED)
elif pseudo == ":required":
sel.selectors.append(CSS_REQUIRED)
elif pseudo == ":optional":
sel.selectors.append(CSS_OPTIONAL)
elif pseudo == ":read-only":
sel.selectors.append(CSS_READ_ONLY)
elif pseudo == ":read-write":
sel.selectors.append(CSS_READ_WRITE)
elif pseudo == ":in-range":
sel.selectors.append(CSS_IN_RANGE)
elif pseudo == ":out-of-range":
sel.selectors.append(CSS_OUT_OF_RANGE)
elif pseudo == ":placeholder-shown":
sel.selectors.append(CSS_PLACEHOLDER_SHOWN)
elif pseudo == ':first-child':
sel.nth.append(ct.SelectorNth(1, False, 0, False, False, ct.SelectorList()))
elif pseudo == ':last-child':
sel.nth.append(ct.SelectorNth(1, False, 0, False, True, ct.SelectorList()))
elif pseudo == ':first-of-type':
sel.nth.append(ct.SelectorNth(1, False, 0, True, False, ct.SelectorList()))
elif pseudo == ':last-of-type':
sel.nth.append(ct.SelectorNth(1, False, 0, True, True, ct.SelectorList()))
elif pseudo == ':only-child':
sel.nth.extend(
[
ct.SelectorNth(1, False, 0, False, False, ct.SelectorList()),
ct.SelectorNth(1, False, 0, False, True, ct.SelectorList())
]
)
elif pseudo == ':only-of-type':
sel.nth.extend(
[
ct.SelectorNth(1, False, 0, True, False, ct.SelectorList()),
ct.SelectorNth(1, False, 0, True, True, ct.SelectorList())
]
)
has_selector = True
elif complex_pseudo and pseudo in PSEUDO_COMPLEX_NO_MATCH:
self.parse_selectors(iselector, m.end(0), FLG_PSEUDO | FLG_OPEN)
sel.no_match = True
has_selector = True
elif not complex_pseudo and pseudo in PSEUDO_SIMPLE_NO_MATCH:
sel.no_match = True
has_selector = True
elif pseudo in PSEUDO_SUPPORTED:
raise SelectorSyntaxError(
"Invalid syntax for pseudo class '{}'".format(pseudo),
self.pattern,
m.start(0)
)
else:
raise NotImplementedError(
"'{}' pseudo-class is not implemented at this time".format(pseudo)
)
return has_selector, is_html
def parse_pseudo_nth(self, sel, m, has_selector, iselector):
"""Parse `nth` pseudo."""
mdict = m.groupdict()
if mdict.get('pseudo_nth_child'):
postfix = '_child'
else:
postfix = '_type'
mdict['name'] = util.lower(css_unescape(mdict['name']))
content = util.lower(mdict.get('nth' + postfix))
if content == 'even':
# 2n
s1 = 2
s2 = 0
var = True
elif content == 'odd':
# 2n+1
s1 = 2
s2 = 1
var = True
else:
nth_parts = RE_NTH.match(content)
s1 = '-' if nth_parts.group('s1') and nth_parts.group('s1') == '-' else ''
a = nth_parts.group('a')
var = a.endswith('n')
if a.startswith('n'):
s1 += '1'
elif var:
s1 += a[:-1]
else:
s1 += a
s2 = '-' if nth_parts.group('s2') and nth_parts.group('s2') == '-' else ''
if nth_parts.group('b'):
s2 += nth_parts.group('b')
else:
s2 = '0'
s1 = int(s1, 10)
s2 = int(s2, 10)
pseudo_sel = mdict['name']
if postfix == '_child':
if m.group('of'):
# Parse the rest of `of S`.
nth_sel = self.parse_selectors(iselector, m.end(0), FLG_PSEUDO | FLG_OPEN)
else:
# Use default `*|*` for `of S`.
nth_sel = CSS_NTH_OF_S_DEFAULT
if pseudo_sel == ':nth-child':
sel.nth.append(ct.SelectorNth(s1, var, s2, False, False, nth_sel))
elif pseudo_sel == ':nth-last-child':
sel.nth.append(ct.SelectorNth(s1, var, s2, False, True, nth_sel))
else:
if pseudo_sel == ':nth-of-type':
sel.nth.append(ct.SelectorNth(s1, var, s2, True, False, ct.SelectorList()))
elif pseudo_sel == ':nth-last-of-type':
sel.nth.append(ct.SelectorNth(s1, var, s2, True, True, ct.SelectorList()))
has_selector = True
return has_selector
def parse_pseudo_open(self, sel, name, has_selector, iselector, index):
"""Parse pseudo with opening bracket."""
flags = FLG_PSEUDO | FLG_OPEN
if name == ':not':
flags |= FLG_NOT
if name == ':has':
flags |= FLG_RELATIVE
sel.selectors.append(self.parse_selectors(iselector, index, flags))
has_selector = True
return has_selector
def parse_has_combinator(self, sel, m, has_selector, selectors, rel_type, index):
"""Parse combinator tokens."""
combinator = m.group('relation').strip()
if not combinator:
combinator = WS_COMBINATOR
if combinator == COMMA_COMBINATOR:
if not has_selector:
# If we've not captured any selector parts, the comma is either at the beginning of the pattern
# or following another comma, both of which are unexpected. Commas must split selectors.
raise SelectorSyntaxError(
"The combinator '{}' at postion {}, must have a selector before it".format(combinator, index),
self.pattern,
index
)
sel.rel_type = rel_type
selectors[-1].relations.append(sel)
rel_type = ":" + WS_COMBINATOR
selectors.append(_Selector())
else:
if has_selector:
# End the current selector and associate the leading combinator with this selector.
sel.rel_type = rel_type
selectors[-1].relations.append(sel)
elif rel_type[1:] != WS_COMBINATOR:
# It's impossible to have two whitespace combinators after each other as the patterns
# will gobble up trailing whitespace. It is also impossible to have a whitespace
# combinator after any other kind for the same reason. But we could have
# multiple non-whitespace combinators. So if the current combinator is not a whitespace,
# then we've hit the multiple combinator case, so we should fail.
raise SelectorSyntaxError(
'The multiple combinators at position {}'.format(index),
self.pattern,
index
)
# Set the leading combinator for the next selector.
rel_type = ':' + combinator
sel = _Selector()
has_selector = False
return has_selector, sel, rel_type
def parse_combinator(self, sel, m, has_selector, selectors, relations, is_pseudo, index):
"""Parse combinator tokens."""
combinator = m.group('relation').strip()
if not combinator:
combinator = WS_COMBINATOR
if not has_selector:
raise SelectorSyntaxError(
"The combinator '{}' at postion {}, must have a selector before it".format(combinator, index),
self.pattern,
index
)
if combinator == COMMA_COMBINATOR:
if not sel.tag and not is_pseudo:
# Implied `*`
sel.tag = ct.SelectorTag('*', None)
sel.relations.extend(relations)
selectors.append(sel)
del relations[:]
else:
sel.relations.extend(relations)
sel.rel_type = combinator
del relations[:]
relations.append(sel)
sel = _Selector()
has_selector = False
return has_selector, sel
def parse_class_id(self, sel, m, has_selector):
"""Parse HTML classes and ids."""
selector = m.group(0)
if selector.startswith('.'):
sel.classes.append(css_unescape(selector[1:]))
else:
sel.ids.append(css_unescape(selector[1:]))
has_selector = True
return has_selector
def parse_pseudo_contains(self, sel, m, has_selector):
"""Parse contains."""
values = m.group('values')
patterns = []
for token in RE_VALUES.finditer(values):
if token.group('split'):
continue
value = token.group('value')
if value.startswith(("'", '"')):
value = css_unescape(value[1:-1], True)
else:
value = css_unescape(value)
patterns.append(value)
sel.contains.append(ct.SelectorContains(tuple(patterns)))
has_selector = True
return has_selector
def parse_pseudo_lang(self, sel, m, has_selector):
"""Parse pseudo language."""
values = m.group('values')
patterns = []
for token in RE_VALUES.finditer(values):
if token.group('split'):
continue
value = token.group('value')
if value.startswith(('"', "'")):
parts = css_unescape(value[1:-1], True).split('-')
else:
parts = css_unescape(value).split('-')
new_parts = []
first = True
for part in parts:
if part == '*' and first:
new_parts.append('(?!x\b)[a-z0-9]+?')
elif part != '*':
new_parts.append(('' if first else '(-(?!x\b)[a-z0-9]+)*?\\-') + re.escape(part))
if first:
first = False
patterns.append(re.compile(r'^{}(?:-.*)?$'.format(''.join(new_parts)), re.I))
sel.lang.append(ct.SelectorLang(patterns))
has_selector = True
return has_selector
def parse_pseudo_dir(self, sel, m, has_selector):
"""Parse pseudo direction."""
value = ct.SEL_DIR_LTR if util.lower(m.group('dir')) == 'ltr' else ct.SEL_DIR_RTL
sel.flags |= value
has_selector = True
return has_selector
def parse_selectors(self, iselector, index=0, flags=0):
"""Parse selectors."""
sel = _Selector()
selectors = []
has_selector = False
closed = False
relations = []
rel_type = ":" + WS_COMBINATOR
is_open = bool(flags & FLG_OPEN)
is_pseudo = bool(flags & FLG_PSEUDO)
is_relative = bool(flags & FLG_RELATIVE)
is_not = bool(flags & FLG_NOT)
is_html = bool(flags & FLG_HTML)
is_default = bool(flags & FLG_DEFAULT)
is_indeterminate = bool(flags & FLG_INDETERMINATE)
is_in_range = bool(flags & FLG_IN_RANGE)
is_out_of_range = bool(flags & FLG_OUT_OF_RANGE)
if self.debug: # pragma: no cover
if is_pseudo:
print(' is_pseudo: True')
if is_open:
print(' is_open: True')
if is_relative:
print(' is_relative: True')
if is_not:
print(' is_not: True')
if is_html:
print(' is_html: True')
if is_default:
print(' is_default: True')
if is_indeterminate:
print(' is_indeterminate: True')
if is_in_range:
print(' is_in_range: True')
if is_out_of_range:
print(' is_out_of_range: True')
if is_relative:
selectors.append(_Selector())
try:
while True:
key, m = next(iselector)
# Handle parts
if key == "at_rule":
raise NotImplementedError("At-rules found at position {}".format(m.start(0)))
elif key == 'pseudo_class_custom':
has_selector = self.parse_pseudo_class_custom(sel, m, has_selector)
elif key == 'pseudo_class':
has_selector, is_html = self.parse_pseudo_class(sel, m, has_selector, iselector, is_html)
elif key == 'pseudo_element':
raise NotImplementedError("Psuedo-element found at position {}".format(m.start(0)))
elif key == 'pseudo_contains':
has_selector = self.parse_pseudo_contains(sel, m, has_selector)
elif key in ('pseudo_nth_type', 'pseudo_nth_child'):
has_selector = self.parse_pseudo_nth(sel, m, has_selector, iselector)
elif key == 'pseudo_lang':
has_selector = self.parse_pseudo_lang(sel, m, has_selector)
elif key == 'pseudo_dir':
has_selector = self.parse_pseudo_dir(sel, m, has_selector)
# Currently only supports HTML
is_html = True
elif key == 'pseudo_close':
if not has_selector:
raise SelectorSyntaxError(
"Expected a selector at postion {}".format(m.start(0)),
self.pattern,
m.start(0)
)
if is_open:
closed = True
break
else:
raise SelectorSyntaxError(
"Unmatched pseudo-class close at postion {}".format(m.start(0)),
self.pattern,
m.start(0)
)
elif key == 'combine':
if is_relative:
has_selector, sel, rel_type = self.parse_has_combinator(
sel, m, has_selector, selectors, rel_type, index
)
else:
has_selector, sel = self.parse_combinator(
sel, m, has_selector, selectors, relations, is_pseudo, index
)
elif key == 'attribute':
has_selector = self.parse_attribute_selector(sel, m, has_selector)
elif key == 'tag':
if has_selector:
raise SelectorSyntaxError(
"Tag name found at position {} instead of at the start".format(m.start(0)),
self.pattern,
m.start(0)
)
has_selector = self.parse_tag_pattern(sel, m, has_selector)
elif key in ('class', 'id'):
has_selector = self.parse_class_id(sel, m, has_selector)
index = m.end(0)
except StopIteration:
pass
if is_open and not closed:
raise SelectorSyntaxError(
"Unclosed pseudo-class at position {}".format(index),
self.pattern,
index
)
if has_selector:
if not sel.tag and not is_pseudo:
# Implied `*`
sel.tag = ct.SelectorTag('*', None)
if is_relative:
sel.rel_type = rel_type
selectors[-1].relations.append(sel)
else:
sel.relations.extend(relations)
del relations[:]
selectors.append(sel)
else:
# We will always need to finish a selector when `:has()` is used as it leads with combining.
raise SelectorSyntaxError(
'Expected a selector at position {}'.format(index),
self.pattern,
index
)
# Some patterns require additional logic, such as default. We try to make these the
# last pattern, and append the appropriate flag to that selector which communicates
# to the matcher what additional logic is required.
if is_default:
selectors[-1].flags = ct.SEL_DEFAULT
if is_indeterminate:
selectors[-1].flags = ct.SEL_INDETERMINATE
if is_in_range:
selectors[-1].flags = ct.SEL_IN_RANGE
if is_out_of_range:
selectors[-1].flags = ct.SEL_OUT_OF_RANGE
return ct.SelectorList([s.freeze() for s in selectors], is_not, is_html)
def selector_iter(self, pattern):
"""Iterate selector tokens."""
# Ignore whitespace and comments at start and end of pattern
m = RE_WS_BEGIN.search(pattern)
index = m.end(0) if m else 0
m = RE_WS_END.search(pattern)
end = (m.start(0) - 1) if m else (len(pattern) - 1)
if self.debug: # pragma: no cover
print('## PARSING: {!r}'.format(pattern))
while index <= end:
m = None
for v in self.css_tokens:
if not v.enabled(self.flags): # pragma: no cover
continue
m = v.match(pattern, index)
if m:
name = v.get_name()
if self.debug: # pragma: no cover
print("TOKEN: '{}' --> {!r} at position {}".format(name, m.group(0), m.start(0)))
index = m.end(0)
yield name, m
break
if m is None:
c = pattern[index]
# If the character represents the start of one of the known selector types,
# throw an exception mentioning that the known selector type is in error;
# otherwise, report the invalid character.
if c == '[':
msg = "Malformed attribute selector at position {}".format(index)
elif c == '.':
msg = "Malformed class selector at position {}".format(index)
elif c == '#':
msg = "Malformed id selector at position {}".format(index)
elif c == ':':
msg = "Malformed pseudo-class selector at position {}".format(index)
else:
msg = "Invalid character {!r} position {}".format(c, index)
raise SelectorSyntaxError(msg, self.pattern, index)
if self.debug: # pragma: no cover
print('## END PARSING')
def process_selectors(self, index=0, flags=0):
"""Process selectors."""
return self.parse_selectors(self.selector_iter(self.pattern), index, flags)
# Precompile CSS selector lists for pseudo-classes (additional logic may be required beyond the pattern)
# A few patterns are order dependent as they use patterns previous compiled.
# CSS pattern for `:link` and `:any-link`
CSS_LINK = CSSParser(
'html|*:is(a, area, link)[href]'
).process_selectors(flags=FLG_PSEUDO | FLG_HTML)
# CSS pattern for `:checked`
CSS_CHECKED = CSSParser(
'''
html|*:is(input[type=checkbox], input[type=radio])[checked],
html|select > html|option[selected]
'''
).process_selectors(flags=FLG_PSEUDO | FLG_HTML)
# CSS pattern for `:default` (must compile CSS_CHECKED first)
CSS_DEFAULT = CSSParser(
'''
:checked,
/*
This pattern must be at the end.
Special logic is applied to the last selector.
*/
html|form html|*:is(button, input)[type="submit"]
'''
).process_selectors(flags=FLG_PSEUDO | FLG_HTML | FLG_DEFAULT)
# CSS pattern for `:indeterminate`
CSS_INDETERMINATE = CSSParser(
'''
html|input[type="checkbox"][indeterminate],
html|input[type="radio"]:is(:not([name]), [name=""]):not([checked]),
html|progress:not([value]),
/*
This pattern must be at the end.
Special logic is applied to the last selector.
*/
html|input[type="radio"][name][name!='']:not([checked])
'''
).process_selectors(flags=FLG_PSEUDO | FLG_HTML | FLG_INDETERMINATE)
# CSS pattern for `:disabled`
CSS_DISABLED = CSSParser(
'''
html|*:is(input[type!=hidden], button, select, textarea, fieldset, optgroup, option, fieldset)[disabled],
html|optgroup[disabled] > html|option,
html|fieldset[disabled] > html|*:is(input[type!=hidden], button, select, textarea, fieldset),
html|fieldset[disabled] >
html|*:not(legend:nth-of-type(1)) html|*:is(input[type!=hidden], button, select, textarea, fieldset)
'''
).process_selectors(flags=FLG_PSEUDO | FLG_HTML)
# CSS pattern for `:enabled`
CSS_ENABLED = CSSParser(
'''
html|*:is(input[type!=hidden], button, select, textarea, fieldset, optgroup, option, fieldset):not(:disabled)
'''
).process_selectors(flags=FLG_PSEUDO | FLG_HTML)
# CSS pattern for `:required`
CSS_REQUIRED = CSSParser(
'html|*:is(input, textarea, select)[required]'
).process_selectors(flags=FLG_PSEUDO | FLG_HTML)
# CSS pattern for `:optional`
CSS_OPTIONAL = CSSParser(
'html|*:is(input, textarea, select):not([required])'
).process_selectors(flags=FLG_PSEUDO | FLG_HTML)
# CSS pattern for `:placeholder-shown`
CSS_PLACEHOLDER_SHOWN = CSSParser(
'''
html|*:is(
input:is(
:not([type]),
[type=""],
[type=text],
[type=search],
[type=url],
[type=tel],
[type=email],
[type=password],
[type=number]
),
textarea
)[placeholder][placeholder!='']
'''
).process_selectors(flags=FLG_PSEUDO | FLG_HTML)
# CSS pattern default for `:nth-child` "of S" feature
CSS_NTH_OF_S_DEFAULT = CSSParser(
'*|*'
).process_selectors(flags=FLG_PSEUDO)
# CSS pattern for `:read-write` (CSS_DISABLED must be compiled first)
CSS_READ_WRITE = CSSParser(
'''
html|*:is(
textarea,
input:is(
:not([type]),
[type=""],
[type=text],
[type=search],
[type=url],
[type=tel],
[type=email],
[type=number],
[type=password],
[type=date],
[type=datetime-local],
[type=month],
[type=time],
[type=week]
)
):not([readonly], :disabled),
html|*:is([contenteditable=""], [contenteditable="true" i])
'''
).process_selectors(flags=FLG_PSEUDO | FLG_HTML)
# CSS pattern for `:read-only`
CSS_READ_ONLY = CSSParser(
'''
html|*:not(:read-write)
'''
).process_selectors(flags=FLG_PSEUDO | FLG_HTML)
# CSS pattern for `:in-range`
CSS_IN_RANGE = CSSParser(
'''
html|input:is(
[type="date"],
[type="month"],
[type="week"],
[type="time"],
[type="datetime-local"],
[type="number"],
[type="range"]
):is(
[min],
[max]
)
'''
).process_selectors(flags=FLG_PSEUDO | FLG_IN_RANGE | FLG_HTML)
# CSS pattern for `:out-of-range`
CSS_OUT_OF_RANGE = CSSParser(
'''
html|input:is(
[type="date"],
[type="month"],
[type="week"],
[type="time"],
[type="datetime-local"],
[type="number"],
[type="range"]
):is(
[min],
[max]
)
'''
).process_selectors(flags=FLG_PSEUDO | FLG_OUT_OF_RANGE | FLG_HTML)
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