debian-python-cssselect2/cssselect2/__init__.py

115 lines
3.5 KiB
Python

# coding: utf8
"""
cssselect2
----------
CSS selectors for ElementTree.
:copyright: (c) 2012 by Simon Sapin, 2017 by Guillaume Ayoub.
:license: BSD, see LICENSE for more details.
"""
from __future__ import unicode_literals
import operator
from webencodings import ascii_lower
# Classes are imported here to expose them at the top level of the module
from .compiler import compile_selector_list # noqa
from .parser import SelectorError # noqa
from .tree import ElementWrapper # noqa
VERSION = '0.2.1'
class Matcher(object):
"""A CSS selectors storage that can match against HTML elements."""
def __init__(self):
self.id_selectors = {}
self.class_selectors = {}
self.lower_local_name_selectors = {}
self.namespace_selectors = {}
self.other_selectors = []
self.order = 0
def add_selector(self, selector, payload):
"""
Add a selector and its payload to the matcher.
:param selector:
A :class:`CompiledSelector` object.
:param payload:
Some data associated to the selector,
such as :class:`declarations <~tinycss2.ast.Declaration>`
parsed from the :attr:`~tinycss2.ast.QualifiedRule.content`
of a style rule.
It can be any Python object,
and will be returned as-is by :meth:`match`.
"""
self.order += 1
if selector.never_matches:
return
entry = (
selector.test, selector.specificity, self.order,
selector.pseudo_element, payload)
if selector.id is not None:
self.id_selectors.setdefault(selector.id, []).append(entry)
elif selector.class_name is not None:
self.class_selectors.setdefault(selector.class_name, []) \
.append(entry)
elif selector.local_name is not None:
self.lower_local_name_selectors.setdefault(
selector.lower_local_name, []).append(entry)
elif selector.namespace is not None:
self.namespace_selectors.setdefault(selector.namespace, []) \
.append(entry)
else:
self.other_selectors.append(entry)
def match(self, element):
"""
Match selectors against the given element.
:param element:
An :class:`ElementWrapper`.
:returns:
A list of the :obj:`payload` objects associated
to selectors that match element,
in order of lowest to highest :attr:`~CompiledSelector.specificity`
and in order of addition with :meth:`add_selector`
among selectors of equal specificity.
"""
relevant_selectors = []
if element.id is not None:
relevant_selectors.append(self.id_selectors.get(element.id, []))
for class_name in element.classes:
relevant_selectors.append(self.class_selectors.get(class_name, []))
relevant_selectors.append(
self.lower_local_name_selectors.get(
ascii_lower(element.local_name), []))
relevant_selectors.append(
self.namespace_selectors.get(element.namespace_url, []))
relevant_selectors.append(self.other_selectors)
results = [
(specificity, order, pseudo, payload)
for selector_list in relevant_selectors
for test, specificity, order, pseudo, payload in selector_list
if test(element)
]
results.sort(key=SORT_KEY)
return results
SORT_KEY = operator.itemgetter(0, 1)