968 lines
42 KiB
Python
968 lines
42 KiB
Python
"""
|
||
weasyprint.css
|
||
--------------
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This module takes care of steps 3 and 4 of “CSS 2.1 processing model”:
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Retrieve stylesheets associated with a document and annotate every element
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with a value for every CSS property.
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http://www.w3.org/TR/CSS21/intro.html#processing-model
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This module does this in more than two steps. The
|
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:func:`get_all_computed_styles` function does everything, but it is itsef
|
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based on other functions in this module.
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:copyright: Copyright 2011-2019 Simon Sapin and contributors, see AUTHORS.
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:license: BSD, see LICENSE for details.
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"""
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from collections import namedtuple
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from logging import DEBUG, WARNING
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import cssselect2
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import tinycss2
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import tinycss2.nth
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from .. import CSS
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from ..logger import LOGGER, PROGRESS_LOGGER
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from ..urls import URLFetchingError, get_url_attribute, url_join
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from . import computed_values, media_queries
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from .properties import INHERITED, INITIAL_NOT_COMPUTED, INITIAL_VALUES
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from .utils import remove_whitespace
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from .validation import preprocess_declarations
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from .validation.descriptors import preprocess_descriptors
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# Reject anything not in here:
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PSEUDO_ELEMENTS = (
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None, 'before', 'after', 'marker', 'first-line', 'first-letter')
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PageType = namedtuple('PageType', ['side', 'blank', 'first', 'index', 'name'])
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class StyleFor:
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"""Convenience function to get the computed styles for an element."""
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def __init__(self, html, sheets, presentational_hints, target_collector):
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# keys: (element, pseudo_element_type)
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# element: an ElementTree Element or the '@page' string
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# pseudo_element_type: a string such as 'first' (for @page) or
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# 'after', or None for normal elements
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# values: dicts of
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# keys: property name as a string
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# values: (values, weight)
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# values: a PropertyValue-like object
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# weight: values with a greater weight take precedence, see
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# http://www.w3.org/TR/CSS21/cascade.html#cascading-order
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self._cascaded_styles = cascaded_styles = {}
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# keys: (element, pseudo_element_type), like cascaded_styles
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# values: style dict objects:
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# keys: property name as a string
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# values: a PropertyValue-like object
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self._computed_styles = {}
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self._sheets = sheets
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PROGRESS_LOGGER.info('Step 3 - Applying CSS')
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for specificity, attributes in find_style_attributes(
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html.etree_element, presentational_hints, html.base_url):
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element, declarations, base_url = attributes
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style = cascaded_styles.setdefault((element, None), {})
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for name, values, importance in preprocess_declarations(
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base_url, declarations):
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precedence = declaration_precedence('author', importance)
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weight = (precedence, specificity)
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old_weight = style.get(name, (None, None))[1]
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if old_weight is None or old_weight <= weight:
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style[name] = values, weight
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# First, add declarations and set computed styles for "real" elements
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# *in tree order*. Tree order is important so that parents have
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# computed styles before their children, for inheritance.
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# Iterate on all elements, even if there is no cascaded style for them.
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for element in html.wrapper_element.iter_subtree():
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for sheet, origin, sheet_specificity in sheets:
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# Add declarations for matched elements
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for selector in sheet.matcher.match(element):
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specificity, order, pseudo_type, declarations = selector
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specificity = sheet_specificity or specificity
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style = cascaded_styles.setdefault(
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(element.etree_element, pseudo_type), {})
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for name, values, importance in declarations:
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precedence = declaration_precedence(origin, importance)
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weight = (precedence, specificity)
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old_weight = style.get(name, (None, None))[1]
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if old_weight is None or old_weight <= weight:
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style[name] = values, weight
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parent = element.parent.etree_element if element.parent else None
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self.set_computed_styles(
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element.etree_element, root=html.etree_element, parent=parent,
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base_url=html.base_url, target_collector=target_collector)
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# Then computed styles for pseudo elements, in any order.
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# Pseudo-elements inherit from their associated element so they come
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# last. Do them in a second pass as there is no easy way to iterate
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# on the pseudo-elements for a given element with the current structure
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# of cascaded_styles. (Keys are (element, pseudo_type) tuples.)
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# Only iterate on pseudo-elements that have cascaded styles. (Others
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# might as well not exist.)
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for element, pseudo_type in cascaded_styles:
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if pseudo_type and not isinstance(element, PageType):
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||
self.set_computed_styles(
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element, pseudo_type=pseudo_type,
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# The pseudo-element inherits from the element.
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root=html.etree_element, parent=element,
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base_url=html.base_url, target_collector=target_collector)
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# Clear the cascaded styles, we don't need them anymore. Keep the
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# dictionary, it is used later for page margins.
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self._cascaded_styles.clear()
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def __call__(self, element, pseudo_type=None):
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style = self._computed_styles.get((element, pseudo_type))
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if style:
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if 'table' in style['display']:
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if (style['display'] in ('table', 'inline-table') and
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style['border_collapse'] == 'collapse'):
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# Padding do not apply
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for side in ['top', 'bottom', 'left', 'right']:
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style['padding_' + side] = computed_values.ZERO_PIXELS
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||
if (style['display'].startswith('table-') and
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||
style['display'] != 'table-caption'):
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# Margins do not apply
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for side in ['top', 'bottom', 'left', 'right']:
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style['margin_' + side] = computed_values.ZERO_PIXELS
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return style
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def set_computed_styles(self, element, parent, root=None, pseudo_type=None,
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base_url=None, target_collector=None):
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"""Set the computed values of styles to ``element``.
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||
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Take the properties left by ``apply_style_rule`` on an element or
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pseudo-element and assign computed values with respect to the cascade,
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declaration priority (ie. ``!important``) and selector specificity.
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||
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"""
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cascaded_styles = self.get_cascaded_styles()
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computed_styles = self.get_computed_styles()
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if element == root and pseudo_type is None:
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assert parent is None
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parent_style = None
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root_style = {
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||
# When specified on the font-size property of the root element,
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# the rem units refer to the property’s initial value.
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'font_size': INITIAL_VALUES['font_size'],
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}
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else:
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assert parent is not None
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||
parent_style = computed_styles[parent, None]
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root_style = computed_styles[root, None]
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||
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cascaded = cascaded_styles.get((element, pseudo_type), {})
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computed_styles[element, pseudo_type] = computed_from_cascaded(
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element, cascaded, parent_style, pseudo_type, root_style, base_url,
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target_collector)
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||
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||
# The style of marker is deleted when display is different from
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# list-item.
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if pseudo_type is None:
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for pseudo in (None, 'before', 'after'):
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pseudo_style = cascaded_styles.get((element, pseudo), {})
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||
if 'display' in pseudo_style:
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||
if pseudo_style['display'][0] == 'list-item':
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||
break
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else:
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if (element, 'marker') in cascaded_styles:
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del cascaded_styles[element, 'marker']
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def add_page_declarations(self, page_type):
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for sheet, origin, sheet_specificity in self._sheets:
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for _rule, selector_list, declarations in sheet.page_rules:
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||
for selector in selector_list:
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||
specificity, pseudo_type, selector_page_type = selector
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||
if self._page_type_match(selector_page_type, page_type):
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||
specificity = sheet_specificity or specificity
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style = self._cascaded_styles.setdefault(
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||
(page_type, pseudo_type), {})
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||
for name, values, importance in declarations:
|
||
precedence = declaration_precedence(
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||
origin, importance)
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||
weight = (precedence, specificity)
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||
old_weight = style.get(name, (None, None))[1]
|
||
if old_weight is None or old_weight <= weight:
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||
style[name] = values, weight
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||
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||
def get_cascaded_styles(self):
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||
return self._cascaded_styles
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||
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||
def get_computed_styles(self):
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||
return self._computed_styles
|
||
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||
@staticmethod
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def _page_type_match(selector_page_type, page_type):
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||
if selector_page_type.side not in (None, page_type.side):
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||
return False
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||
if selector_page_type.blank not in (None, page_type.blank):
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||
return False
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||
if selector_page_type.first not in (None, page_type.first):
|
||
return False
|
||
if selector_page_type.name not in (None, page_type.name):
|
||
return False
|
||
if selector_page_type.index is not None:
|
||
a, b, group = selector_page_type.index
|
||
# TODO: handle group
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||
if a:
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||
if (page_type.index + 1 - b) % a:
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||
return False
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||
else:
|
||
if page_type.index + 1 != b:
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||
return False
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||
return True
|
||
|
||
|
||
def get_child_text(element):
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||
"""Return the text directly in the element, not descendants."""
|
||
content = [element.text] if element.text else []
|
||
for child in element:
|
||
if child.tail:
|
||
content.append(child.tail)
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||
return ''.join(content)
|
||
|
||
|
||
def find_stylesheets(wrapper_element, device_media_type, url_fetcher, base_url,
|
||
font_config, page_rules):
|
||
"""Yield the stylesheets in ``element_tree``.
|
||
|
||
The output order is the same as the source order.
|
||
|
||
"""
|
||
from ..html import element_has_link_type # Work around circular imports.
|
||
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for wrapper in wrapper_element.query_all('style', 'link'):
|
||
element = wrapper.etree_element
|
||
mime_type = element.get('type', 'text/css').split(';', 1)[0].strip()
|
||
# Only keep 'type/subtype' from 'type/subtype ; param1; param2'.
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||
if mime_type != 'text/css':
|
||
continue
|
||
media_attr = element.get('media', '').strip() or 'all'
|
||
media = [media_type.strip() for media_type in media_attr.split(',')]
|
||
if not media_queries.evaluate_media_query(media, device_media_type):
|
||
continue
|
||
if element.tag == 'style':
|
||
# Content is text that is directly in the <style> element, not its
|
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# descendants
|
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content = get_child_text(element)
|
||
# ElementTree should give us either unicode or ASCII-only
|
||
# bytestrings, so we don't need `encoding` here.
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||
css = CSS(
|
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string=content, base_url=base_url,
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url_fetcher=url_fetcher, media_type=device_media_type,
|
||
font_config=font_config, page_rules=page_rules)
|
||
yield css
|
||
elif element.tag == 'link' and element.get('href'):
|
||
if not element_has_link_type(element, 'stylesheet') or \
|
||
element_has_link_type(element, 'alternate'):
|
||
continue
|
||
href = get_url_attribute(element, 'href', base_url)
|
||
if href is not None:
|
||
try:
|
||
yield CSS(
|
||
url=href, url_fetcher=url_fetcher,
|
||
_check_mime_type=True, media_type=device_media_type,
|
||
font_config=font_config, page_rules=page_rules)
|
||
except URLFetchingError as exc:
|
||
LOGGER.error(
|
||
'Failed to load stylesheet at %s : %s', href, exc)
|
||
|
||
|
||
def find_style_attributes(tree, presentational_hints=False, base_url=None):
|
||
"""Yield ``specificity, (element, declaration, base_url)`` rules.
|
||
|
||
Rules from "style" attribute are returned with specificity
|
||
``(1, 0, 0)``.
|
||
|
||
If ``presentational_hints`` is ``True``, rules from presentational hints
|
||
are returned with specificity ``(0, 0, 0)``.
|
||
|
||
"""
|
||
def check_style_attribute(element, style_attribute):
|
||
declarations = tinycss2.parse_declaration_list(style_attribute)
|
||
return element, declarations, base_url
|
||
|
||
for element in tree.iter():
|
||
specificity = (1, 0, 0)
|
||
style_attribute = element.get('style')
|
||
if style_attribute:
|
||
yield specificity, check_style_attribute(element, style_attribute)
|
||
if not presentational_hints:
|
||
continue
|
||
specificity = (0, 0, 0)
|
||
if element.tag == 'body':
|
||
# TODO: we should check the container frame element
|
||
for part, position in (
|
||
('height', 'top'), ('height', 'bottom'),
|
||
('width', 'left'), ('width', 'right')):
|
||
style_attribute = None
|
||
for prop in ('margin%s' % part, '%smargin' % position):
|
||
if element.get(prop):
|
||
style_attribute = 'margin-%s:%spx' % (
|
||
position, element.get(prop))
|
||
break
|
||
if style_attribute:
|
||
yield specificity, check_style_attribute(
|
||
element, style_attribute)
|
||
if element.get('background'):
|
||
style_attribute = 'background-image:url(%s)' % (
|
||
element.get('background'))
|
||
yield specificity, check_style_attribute(
|
||
element, style_attribute)
|
||
if element.get('bgcolor'):
|
||
style_attribute = 'background-color:%s' % (
|
||
element.get('bgcolor'))
|
||
yield specificity, check_style_attribute(
|
||
element, style_attribute)
|
||
if element.get('text'):
|
||
style_attribute = 'color:%s' % element.get('text')
|
||
yield specificity, check_style_attribute(
|
||
element, style_attribute)
|
||
# TODO: we should support link, vlink, alink
|
||
elif element.tag == 'center':
|
||
yield specificity, check_style_attribute(
|
||
element, 'text-align:center')
|
||
elif element.tag == 'div':
|
||
align = element.get('align', '').lower()
|
||
if align == 'middle':
|
||
yield specificity, check_style_attribute(
|
||
element, 'text-align:center')
|
||
elif align in ('center', 'left', 'right', 'justify'):
|
||
yield specificity, check_style_attribute(
|
||
element, 'text-align:%s' % align)
|
||
elif element.tag == 'font':
|
||
if element.get('color'):
|
||
yield specificity, check_style_attribute(
|
||
element, 'color:%s' % element.get('color'))
|
||
if element.get('face'):
|
||
yield specificity, check_style_attribute(
|
||
element, 'font-family:%s' % element.get('face'))
|
||
if element.get('size'):
|
||
size = element.get('size').strip()
|
||
relative_plus = size.startswith('+')
|
||
relative_minus = size.startswith('-')
|
||
if relative_plus or relative_minus:
|
||
size = size[1:].strip()
|
||
try:
|
||
size = int(size)
|
||
except ValueError:
|
||
LOGGER.warning('Invalid value for size: %s', size)
|
||
else:
|
||
font_sizes = {
|
||
1: 'x-small',
|
||
2: 'small',
|
||
3: 'medium',
|
||
4: 'large',
|
||
5: 'x-large',
|
||
6: 'xx-large',
|
||
7: '48px', # 1.5 * xx-large
|
||
}
|
||
if relative_plus:
|
||
size += 3
|
||
elif relative_minus:
|
||
size -= 3
|
||
size = max(1, min(7, size))
|
||
yield specificity, check_style_attribute(
|
||
element, 'font-size:%s' % font_sizes[size])
|
||
elif element.tag == 'table':
|
||
if element.get('cellspacing'):
|
||
yield specificity, check_style_attribute(
|
||
element,
|
||
'border-spacing:%spx' % element.get('cellspacing'))
|
||
if element.get('cellpadding'):
|
||
cellpadding = element.get('cellpadding')
|
||
if cellpadding.isdigit():
|
||
cellpadding += 'px'
|
||
# TODO: don't match subtables cells
|
||
for subelement in element.iter():
|
||
if subelement.tag in ('td', 'th'):
|
||
yield specificity, check_style_attribute(
|
||
subelement,
|
||
'padding-left:%s;padding-right:%s;'
|
||
'padding-top:%s;padding-bottom:%s;' % (
|
||
4 * (cellpadding,)))
|
||
if element.get('hspace'):
|
||
hspace = element.get('hspace')
|
||
if hspace.isdigit():
|
||
hspace += 'px'
|
||
yield specificity, check_style_attribute(
|
||
element,
|
||
'margin-left:%s;margin-right:%s' % (hspace, hspace))
|
||
if element.get('vspace'):
|
||
vspace = element.get('vspace')
|
||
if vspace.isdigit():
|
||
vspace += 'px'
|
||
yield specificity, check_style_attribute(
|
||
element,
|
||
'margin-top:%s;margin-bottom:%s' % (vspace, vspace))
|
||
if element.get('width'):
|
||
style_attribute = 'width:%s' % element.get('width')
|
||
if element.get('width').isdigit():
|
||
style_attribute += 'px'
|
||
yield specificity, check_style_attribute(
|
||
element, style_attribute)
|
||
if element.get('height'):
|
||
style_attribute = 'height:%s' % element.get('height')
|
||
if element.get('height').isdigit():
|
||
style_attribute += 'px'
|
||
yield specificity, check_style_attribute(
|
||
element, style_attribute)
|
||
if element.get('background'):
|
||
style_attribute = 'background-image:url(%s)' % (
|
||
element.get('background'))
|
||
yield specificity, check_style_attribute(
|
||
element, style_attribute)
|
||
if element.get('bgcolor'):
|
||
style_attribute = 'background-color:%s' % (
|
||
element.get('bgcolor'))
|
||
yield specificity, check_style_attribute(
|
||
element, style_attribute)
|
||
if element.get('bordercolor'):
|
||
style_attribute = 'border-color:%s' % (
|
||
element.get('bordercolor'))
|
||
yield specificity, check_style_attribute(
|
||
element, style_attribute)
|
||
if element.get('border'):
|
||
style_attribute = 'border-width:%spx' % (
|
||
element.get('border'))
|
||
yield specificity, check_style_attribute(
|
||
element, style_attribute)
|
||
elif element.tag in ('tr', 'td', 'th', 'thead', 'tbody', 'tfoot'):
|
||
align = element.get('align', '').lower()
|
||
# TODO: we should align descendants too
|
||
if align == 'middle':
|
||
yield specificity, check_style_attribute(
|
||
element, 'text-align:center')
|
||
elif align in ('center', 'left', 'right', 'justify'):
|
||
yield specificity, check_style_attribute(
|
||
element, 'text-align:%s' % align)
|
||
if element.get('background'):
|
||
style_attribute = 'background-image:url(%s)' % (
|
||
element.get('background'))
|
||
yield specificity, check_style_attribute(
|
||
element, style_attribute)
|
||
if element.get('bgcolor'):
|
||
style_attribute = 'background-color:%s' % (
|
||
element.get('bgcolor'))
|
||
yield specificity, check_style_attribute(
|
||
element, style_attribute)
|
||
if element.tag in ('tr', 'td', 'th'):
|
||
if element.get('height'):
|
||
style_attribute = 'height:%s' % element.get('height')
|
||
if element.get('height').isdigit():
|
||
style_attribute += 'px'
|
||
yield specificity, check_style_attribute(
|
||
element, style_attribute)
|
||
if element.tag in ('td', 'th'):
|
||
if element.get('width'):
|
||
style_attribute = 'width:%s' % element.get('width')
|
||
if element.get('width').isdigit():
|
||
style_attribute += 'px'
|
||
yield specificity, check_style_attribute(
|
||
element, style_attribute)
|
||
elif element.tag == 'caption':
|
||
align = element.get('align', '').lower()
|
||
# TODO: we should align descendants too
|
||
if align == 'middle':
|
||
yield specificity, check_style_attribute(
|
||
element, 'text-align:center')
|
||
elif align in ('center', 'left', 'right', 'justify'):
|
||
yield specificity, check_style_attribute(
|
||
element, 'text-align:%s' % align)
|
||
elif element.tag == 'col':
|
||
if element.get('width'):
|
||
style_attribute = 'width:%s' % element.get('width')
|
||
if element.get('width').isdigit():
|
||
style_attribute += 'px'
|
||
yield specificity, check_style_attribute(
|
||
element, style_attribute)
|
||
elif element.tag == 'hr':
|
||
size = 0
|
||
if element.get('size'):
|
||
try:
|
||
size = int(element.get('size'))
|
||
except ValueError:
|
||
LOGGER.warning('Invalid value for size: %s', size)
|
||
if (element.get('color'), element.get('noshade')) != (None, None):
|
||
if size >= 1:
|
||
yield specificity, check_style_attribute(
|
||
element, 'border-width:%spx' % (size / 2))
|
||
elif size == 1:
|
||
yield specificity, check_style_attribute(
|
||
element, 'border-bottom-width:0')
|
||
elif size > 1:
|
||
yield specificity, check_style_attribute(
|
||
element, 'height:%spx' % (size - 2))
|
||
if element.get('width'):
|
||
style_attribute = 'width:%s' % element.get('width')
|
||
if element.get('width').isdigit():
|
||
style_attribute += 'px'
|
||
yield specificity, check_style_attribute(
|
||
element, style_attribute)
|
||
if element.get('color'):
|
||
yield specificity, check_style_attribute(
|
||
element, 'color:%s' % element.get('color'))
|
||
elif element.tag in (
|
||
'iframe', 'applet', 'embed', 'img', 'input', 'object'):
|
||
if (element.tag != 'input' or
|
||
element.get('type', '').lower() == 'image'):
|
||
align = element.get('align', '').lower()
|
||
if align in ('middle', 'center'):
|
||
# TODO: middle and center values are wrong
|
||
yield specificity, check_style_attribute(
|
||
element, 'vertical-align:middle')
|
||
if element.get('hspace'):
|
||
hspace = element.get('hspace')
|
||
if hspace.isdigit():
|
||
hspace += 'px'
|
||
yield specificity, check_style_attribute(
|
||
element,
|
||
'margin-left:%s;margin-right:%s' % (hspace, hspace))
|
||
if element.get('vspace'):
|
||
vspace = element.get('vspace')
|
||
if vspace.isdigit():
|
||
vspace += 'px'
|
||
yield specificity, check_style_attribute(
|
||
element,
|
||
'margin-top:%s;margin-bottom:%s' % (vspace, vspace))
|
||
# TODO: img seems to be excluded for width and height, but a
|
||
# lot of W3C tests rely on this attribute being applied to img
|
||
if element.get('width'):
|
||
style_attribute = 'width:%s' % element.get('width')
|
||
if element.get('width').isdigit():
|
||
style_attribute += 'px'
|
||
yield specificity, check_style_attribute(
|
||
element, style_attribute)
|
||
if element.get('height'):
|
||
style_attribute = 'height:%s' % element.get('height')
|
||
if element.get('height').isdigit():
|
||
style_attribute += 'px'
|
||
yield specificity, check_style_attribute(
|
||
element, style_attribute)
|
||
if element.tag in ('img', 'object', 'input'):
|
||
if element.get('border'):
|
||
yield specificity, check_style_attribute(
|
||
element,
|
||
'border-width:%spx;border-style:solid' %
|
||
element.get('border'))
|
||
elif element.tag == 'ol':
|
||
# From https://www.w3.org/TR/css-lists-3/
|
||
if element.get('start'):
|
||
yield specificity, check_style_attribute(
|
||
element,
|
||
'counter-reset:list-item %s;'
|
||
'counter-increment:list-item -1' % element.get('start'))
|
||
elif element.tag == 'ul':
|
||
# From https://www.w3.org/TR/css-lists-3/
|
||
if element.get('value'):
|
||
yield specificity, check_style_attribute(
|
||
element,
|
||
'counter-reset:list-item %s;'
|
||
'counter-increment:none' % element.get('value'))
|
||
|
||
|
||
def declaration_precedence(origin, importance):
|
||
"""Return the precedence for a declaration.
|
||
|
||
Precedence values have no meaning unless compared to each other.
|
||
|
||
Acceptable values for ``origin`` are the strings ``'author'``, ``'user'``
|
||
and ``'user agent'``.
|
||
|
||
"""
|
||
# See http://www.w3.org/TR/CSS21/cascade.html#cascading-order
|
||
if origin == 'user agent':
|
||
return 1
|
||
elif origin == 'user' and not importance:
|
||
return 2
|
||
elif origin == 'author' and not importance:
|
||
return 3
|
||
elif origin == 'author': # and importance
|
||
return 4
|
||
else:
|
||
assert origin == 'user' # and importance
|
||
return 5
|
||
|
||
|
||
def computed_from_cascaded(element, cascaded, parent_style, pseudo_type=None,
|
||
root_style=None, base_url=None,
|
||
target_collector=None):
|
||
"""Get a dict of computed style mixed from parent and cascaded styles."""
|
||
if not cascaded and parent_style is not None:
|
||
# Fast path for anonymous boxes:
|
||
# no cascaded style, only implicitly initial or inherited values.
|
||
computed = dict(INITIAL_VALUES)
|
||
for name in parent_style:
|
||
if name in INHERITED or name.startswith('__'):
|
||
computed[name] = parent_style[name]
|
||
# page is not inherited but taken from the ancestor if 'auto'
|
||
computed['page'] = parent_style['page']
|
||
# border-*-style is none, so border-width computes to zero.
|
||
# Other than that, properties that would need computing are
|
||
# border-*-color, but they do not apply.
|
||
computed['border_top_width'] = 0
|
||
computed['border_bottom_width'] = 0
|
||
computed['border_left_width'] = 0
|
||
computed['border_right_width'] = 0
|
||
computed['outline_width'] = 0
|
||
return computed
|
||
|
||
# Handle inheritance and initial values
|
||
specified = {}
|
||
computed = {}
|
||
|
||
if parent_style:
|
||
for name in parent_style:
|
||
if name.startswith('__'):
|
||
computed[name] = specified[name] = parent_style[name]
|
||
for name in cascaded:
|
||
if name.startswith('__'):
|
||
computed[name] = specified[name] = cascaded[name][0]
|
||
|
||
for name, initial in INITIAL_VALUES.items():
|
||
if name in cascaded:
|
||
value, _precedence = cascaded[name]
|
||
keyword = value
|
||
else:
|
||
if name in INHERITED:
|
||
keyword = 'inherit'
|
||
else:
|
||
keyword = 'initial'
|
||
|
||
if keyword == 'inherit' and parent_style is None:
|
||
# On the root element, 'inherit' from initial values
|
||
keyword = 'initial'
|
||
|
||
if keyword == 'initial':
|
||
value = initial
|
||
if name not in INITIAL_NOT_COMPUTED:
|
||
# The value is the same as when computed
|
||
computed[name] = value
|
||
elif keyword == 'inherit':
|
||
value = parent_style[name]
|
||
# Values in parent_style are already computed.
|
||
computed[name] = value
|
||
|
||
specified[name] = value
|
||
|
||
if specified['page'] == 'auto':
|
||
# The page property does not inherit. However, if the page value on
|
||
# an element is auto, then its used value is the value specified on
|
||
# its nearest ancestor with a non-auto value. When specified on the
|
||
# root element, the used value for auto is the empty string.
|
||
computed['page'] = specified['page'] = (
|
||
'' if parent_style is None else parent_style['page'])
|
||
|
||
return computed_values.compute(
|
||
element, pseudo_type, specified, computed, parent_style, root_style,
|
||
base_url, target_collector)
|
||
|
||
|
||
def parse_page_selectors(rule):
|
||
"""Parse a page selector rule.
|
||
|
||
Return a list of page data if the rule is correctly parsed. Page data are a
|
||
dict containing:
|
||
|
||
- 'side' ('left', 'right' or None),
|
||
- 'blank' (True or None),
|
||
- 'first' (True or None),
|
||
- 'index' (page number or None),
|
||
- 'name' (page name string or None), and
|
||
- 'specificity' (list of numbers).
|
||
|
||
Return ``None` if something went wrong while parsing the rule.
|
||
|
||
"""
|
||
# See https://drafts.csswg.org/css-page-3/#syntax-page-selector
|
||
|
||
tokens = list(remove_whitespace(rule.prelude))
|
||
page_data = []
|
||
|
||
# TODO: Specificity is probably wrong, should clean and test that.
|
||
if not tokens:
|
||
page_data.append({
|
||
'side': None, 'blank': None, 'first': None, 'index': None,
|
||
'name': None, 'specificity': [0, 0, 0]})
|
||
return page_data
|
||
|
||
while tokens:
|
||
types = {
|
||
'side': None, 'blank': None, 'first': None, 'index': None,
|
||
'name': None, 'specificity': [0, 0, 0]}
|
||
|
||
if tokens[0].type == 'ident':
|
||
token = tokens.pop(0)
|
||
types['name'] = token.value
|
||
types['specificity'][0] = 1
|
||
|
||
if len(tokens) == 1:
|
||
return None
|
||
elif not tokens:
|
||
page_data.append(types)
|
||
return page_data
|
||
|
||
while tokens:
|
||
literal = tokens.pop(0)
|
||
if literal.type != 'literal':
|
||
return None
|
||
|
||
if literal.value == ':':
|
||
if not tokens:
|
||
return None
|
||
|
||
if tokens[0].type == 'ident':
|
||
ident = tokens.pop(0)
|
||
pseudo_class = ident.lower_value
|
||
|
||
if pseudo_class in ('left', 'right'):
|
||
if types['side'] and types['side'] != pseudo_class:
|
||
return None
|
||
types['side'] = pseudo_class
|
||
types['specificity'][2] += 1
|
||
continue
|
||
|
||
elif pseudo_class in ('blank', 'first'):
|
||
types[pseudo_class] = True
|
||
types['specificity'][1] += 1
|
||
continue
|
||
|
||
elif tokens[0].type == 'function':
|
||
function = tokens.pop(0)
|
||
if function.name != 'nth':
|
||
return None
|
||
for i, argument in enumerate(function.arguments):
|
||
if argument.type == 'ident' and argument.value == 'of':
|
||
nth = function.arguments[:i - 1]
|
||
group = function.arguments[i:]
|
||
break
|
||
else:
|
||
nth = function.arguments
|
||
group = None
|
||
|
||
nth_values = tinycss2.nth.parse_nth(nth)
|
||
if nth_values is None:
|
||
return None
|
||
|
||
if group is not None:
|
||
group = [
|
||
token for token in group
|
||
if token.type not in (
|
||
'comment', 'whitespacespace')]
|
||
if len(group) != 1:
|
||
return None
|
||
group, = group
|
||
if group.type != 'ident':
|
||
return None
|
||
group = group.value
|
||
|
||
# TODO: handle page groups
|
||
return None
|
||
|
||
types['index'] = (*nth_values, group)
|
||
# TODO: specificity is not specified yet
|
||
# https://github.com/w3c/csswg-drafts/issues/3524
|
||
types['specificity'][1] += 1
|
||
continue
|
||
|
||
return None
|
||
elif literal.value == ',':
|
||
if tokens and any(types['specificity']):
|
||
break
|
||
else:
|
||
return None
|
||
|
||
page_data.append(types)
|
||
|
||
return page_data
|
||
|
||
|
||
def preprocess_stylesheet(device_media_type, base_url, stylesheet_rules,
|
||
url_fetcher, matcher, page_rules, fonts,
|
||
font_config, ignore_imports=False):
|
||
"""Do the work that can be done early on stylesheet, before they are
|
||
in a document.
|
||
|
||
"""
|
||
for rule in stylesheet_rules:
|
||
if getattr(rule, 'content', None) is None and (
|
||
rule.type != 'at-rule' or rule.lower_at_keyword != 'import'):
|
||
continue
|
||
|
||
if rule.type == 'qualified-rule':
|
||
declarations = list(preprocess_declarations(
|
||
base_url, tinycss2.parse_declaration_list(rule.content)))
|
||
if declarations:
|
||
logger_level = WARNING
|
||
try:
|
||
selectors = cssselect2.compile_selector_list(rule.prelude)
|
||
for selector in selectors:
|
||
matcher.add_selector(selector, declarations)
|
||
if selector.pseudo_element not in PSEUDO_ELEMENTS:
|
||
if selector.pseudo_element.startswith('-'):
|
||
logger_level = DEBUG
|
||
raise cssselect2.SelectorError(
|
||
'ignored prefixed pseudo-element: %s'
|
||
% selector.pseudo_element)
|
||
else:
|
||
raise cssselect2.SelectorError(
|
||
'unknown pseudo-element: %s'
|
||
% selector.pseudo_element)
|
||
ignore_imports = True
|
||
except cssselect2.SelectorError as exc:
|
||
LOGGER.log(
|
||
logger_level,
|
||
"Invalid or unsupported selector '%s', %s",
|
||
tinycss2.serialize(rule.prelude), exc)
|
||
continue
|
||
else:
|
||
ignore_imports = True
|
||
|
||
elif rule.type == 'at-rule' and rule.lower_at_keyword == 'import':
|
||
if ignore_imports:
|
||
LOGGER.warning('@import rule "%s" not at the beginning of the '
|
||
'the whole rule was ignored at %s:%s.',
|
||
tinycss2.serialize(rule.prelude),
|
||
rule.source_line, rule.source_column)
|
||
continue
|
||
|
||
tokens = remove_whitespace(rule.prelude)
|
||
if tokens and tokens[0].type in ('url', 'string'):
|
||
url = tokens[0].value
|
||
else:
|
||
continue
|
||
media = media_queries.parse_media_query(tokens[1:])
|
||
if media is None:
|
||
LOGGER.warning('Invalid media type "%s" '
|
||
'the whole @import rule was ignored at %s:%s.',
|
||
tinycss2.serialize(rule.prelude),
|
||
rule.source_line, rule.source_column)
|
||
continue
|
||
if not media_queries.evaluate_media_query(
|
||
media, device_media_type):
|
||
continue
|
||
url = url_join(
|
||
base_url, url, allow_relative=False,
|
||
context='@import at %s:%s',
|
||
context_args=(rule.source_line, rule.source_column))
|
||
if url is not None:
|
||
try:
|
||
CSS(
|
||
url=url, url_fetcher=url_fetcher,
|
||
media_type=device_media_type, font_config=font_config,
|
||
matcher=matcher, page_rules=page_rules)
|
||
except URLFetchingError as exc:
|
||
LOGGER.error(
|
||
'Failed to load stylesheet at %s : %s', url, exc)
|
||
|
||
elif rule.type == 'at-rule' and rule.lower_at_keyword == 'media':
|
||
media = media_queries.parse_media_query(rule.prelude)
|
||
if media is None:
|
||
LOGGER.warning('Invalid media type "%s" '
|
||
'the whole @media rule was ignored at %s:%s.',
|
||
tinycss2.serialize(rule.prelude),
|
||
rule.source_line, rule.source_column)
|
||
continue
|
||
ignore_imports = True
|
||
if not media_queries.evaluate_media_query(
|
||
media, device_media_type):
|
||
continue
|
||
content_rules = tinycss2.parse_rule_list(rule.content)
|
||
preprocess_stylesheet(
|
||
device_media_type, base_url, content_rules, url_fetcher,
|
||
matcher, page_rules, fonts, font_config, ignore_imports=True)
|
||
|
||
elif rule.type == 'at-rule' and rule.lower_at_keyword == 'page':
|
||
data = parse_page_selectors(rule)
|
||
|
||
if data is None:
|
||
LOGGER.warning(
|
||
'Unsupported @page selector "%s", '
|
||
'the whole @page rule was ignored at %s:%s.',
|
||
tinycss2.serialize(rule.prelude),
|
||
rule.source_line, rule.source_column)
|
||
continue
|
||
|
||
ignore_imports = True
|
||
for page_type in data:
|
||
specificity = page_type.pop('specificity')
|
||
page_type = PageType(**page_type)
|
||
content = tinycss2.parse_declaration_list(rule.content)
|
||
declarations = list(preprocess_declarations(base_url, content))
|
||
|
||
if declarations:
|
||
selector_list = [(specificity, None, page_type)]
|
||
page_rules.append((rule, selector_list, declarations))
|
||
|
||
for margin_rule in content:
|
||
if margin_rule.type != 'at-rule' or (
|
||
margin_rule.content is None):
|
||
continue
|
||
declarations = list(preprocess_declarations(
|
||
base_url,
|
||
tinycss2.parse_declaration_list(margin_rule.content)))
|
||
if declarations:
|
||
selector_list = [(
|
||
specificity, '@' + margin_rule.lower_at_keyword,
|
||
page_type)]
|
||
page_rules.append(
|
||
(margin_rule, selector_list, declarations))
|
||
|
||
elif rule.type == 'at-rule' and rule.lower_at_keyword == 'font-face':
|
||
ignore_imports = True
|
||
content = tinycss2.parse_declaration_list(rule.content)
|
||
rule_descriptors = dict(preprocess_descriptors(base_url, content))
|
||
for key in ('src', 'font_family'):
|
||
if key not in rule_descriptors:
|
||
LOGGER.warning(
|
||
"Missing %s descriptor in '@font-face' rule at %s:%s",
|
||
key.replace('_', '-'),
|
||
rule.source_line, rule.source_column)
|
||
break
|
||
else:
|
||
if font_config is not None:
|
||
font_filename = font_config.add_font_face(
|
||
rule_descriptors, url_fetcher)
|
||
if font_filename:
|
||
fonts.append(font_filename)
|
||
|
||
|
||
def get_all_computed_styles(html, user_stylesheets=None,
|
||
presentational_hints=False, font_config=None,
|
||
page_rules=None, target_collector=None):
|
||
"""Compute all the computed styles of all elements in ``html`` document.
|
||
|
||
Do everything from finding author stylesheets to parsing and applying them.
|
||
|
||
Return a ``style_for`` function that takes an element and an optional
|
||
pseudo-element type, and return a style dict object.
|
||
|
||
"""
|
||
# List stylesheets. Order here is not important ('origin' is).
|
||
sheets = []
|
||
for sheet in (html._ua_stylesheets() or []):
|
||
sheets.append((sheet, 'user agent', None))
|
||
if presentational_hints:
|
||
for sheet in (html._ph_stylesheets() or []):
|
||
sheets.append((sheet, 'author', (0, 0, 0)))
|
||
for sheet in find_stylesheets(
|
||
html.wrapper_element, html.media_type, html.url_fetcher,
|
||
html.base_url, font_config, page_rules):
|
||
sheets.append((sheet, 'author', None))
|
||
for sheet in (user_stylesheets or []):
|
||
sheets.append((sheet, 'user', None))
|
||
|
||
return StyleFor(html, sheets, presentational_hints, target_collector)
|