Files
Chrome2Kindle/server/sx/w3c/css.py
Fergal Moran f8c6e8da3d Initial upload
2010-10-21 21:47:26 +01:00

768 lines
26 KiB
Python
Executable File

#!/usr/bin/env python
##~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
##~ Copyright (C) 2002-2004 TechGame Networks, LLC.
##~
##~ This library is free software; you can redistribute it and/or
##~ modify it under the terms of the BSD style License as found in the
##~ LICENSE file included with this distribution.
##
## Modified by Dirk Holtwick <holtwick@web.de>, 2007-2008
##~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
"""CSS-2.1 engine
Primary classes:
* CSSElementInterfaceAbstract
Provide a concrete implementation for the XML element model used.
* CSSCascadeStrategy
Implements the CSS-2.1 engine's attribute lookup rules.
* CSSParser
Parses CSS source forms into usable results using CSSBuilder and
CSSMutableSelector. You may want to override parseExternal()
* CSSBuilder (and CSSMutableSelector)
A concrete implementation for cssParser.CSSBuilderAbstract (and
cssParser.CSSSelectorAbstract) to provide usable results to
CSSParser requests.
Dependencies:
python 2.3 (or greater)
sets, cssParser, re (via cssParser)
"""
#~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
#~ Imports
#~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
import copy
import sets
import cssParser
import cssSpecial
#~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
#~ Constants / Variables / Etc.
#~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
CSSParseError = cssParser.CSSParseError
#~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
#~ Definitions
#~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
class CSSElementInterfaceAbstract(object):
def getAttr(self, name, default=NotImplemented):
raise NotImplementedError('Subclass responsibility')
def getIdAttr(self):
return self.getAttr('id', '')
def getClassAttr(self):
return self.getAttr('class', '')
def getInlineStyle(self):
raise NotImplementedError('Subclass responsibility')
def matchesNode(self):
raise NotImplementedError('Subclass responsibility')
def inPseudoState(self, name, params=()):
raise NotImplementedError('Subclass responsibility')
def iterXMLParents(self):
"""Results must be compatible with CSSElementInterfaceAbstract"""
raise NotImplementedError('Subclass responsibility')
def getPreviousSibling(self):
raise NotImplementedError('Subclass responsibility')
#~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
class CSSCascadeStrategy(object):
author = None
user = None
userAgenr = None
def __init__(self, author=None, user=None, userAgent=None):
if author is not None:
self.author = author
if user is not None:
self.user = user
if userAgent is not None:
self.userAgenr = userAgent
def copyWithUpdate(self, author=None, user=None, userAgent=None):
if author is None:
author = self.author
if user is None:
user = self.user
if userAgent is None:
userAgent = self.userAgenr
return self.__class__(author, user, userAgent)
#~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
def iterCSSRulesets(self, inline=None):
if self.userAgenr is not None:
yield self.userAgenr[0]
yield self.userAgenr[1]
if self.user is not None:
yield self.user[0]
if self.author is not None:
yield self.author[0]
yield self.author[1]
if inline:
yield inline[0]
yield inline[1]
if self.user is not None:
yield self.user[1]
#~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
def findStyleFor(self, element, attrName, default=NotImplemented):
"""Attempts to find the style setting for attrName in the CSSRulesets.
Note: This method does not attempt to resolve rules that return
"inherited", "default", or values that have units (including "%").
This is left up to the client app to re-query the CSS in order to
implement these semantics.
"""
rule = self.findCSSRulesFor(element, attrName)
return self._extractStyleForRule(rule, attrName, default)
def findStylesForEach(self, element, attrNames, default=NotImplemented):
"""Attempts to find the style setting for attrName in the CSSRulesets.
Note: This method does not attempt to resolve rules that return
"inherited", "default", or values that have units (including "%").
This is left up to the client app to re-query the CSS in order to
implement these semantics.
"""
rules = self.findCSSRulesForEach(element, attrNames)
return [(attrName, self._extractStyleForRule(rule, attrName, default))
for attrName, rule in rules.iteritems()]
def findCSSRulesFor(self, element, attrName):
rules = []
inline = element.getInlineStyle()
for ruleset in self.iterCSSRulesets(inline):
rules += ruleset.findCSSRuleFor(element, attrName)
rules.sort()
return rules
def findCSSRulesForEach(self, element, attrNames):
rules = dict([(name, []) for name in attrNames])
inline = element.getInlineStyle()
for ruleset in self.iterCSSRulesets(inline):
for attrName, attrRules in rules.iteritems():
attrRules += ruleset.findCSSRuleFor(element, attrName)
for attrRules in rules.itervalues():
attrRules.sort()
return rules
#~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
def _extractStyleForRule(self, rule, attrName, default=NotImplemented):
if rule:
# rule is packed in a list to differentiate from "no rule" vs "rule
# whose value evalutates as False"
style = rule[-1][1]
return style[attrName]
elif default is not NotImplemented:
return default
else:
raise LookupError("Could not find style for '%s' in %r" % (attrName, rule))
#~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
#~ CSS Selectors
#~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
class CSSSelectorBase(object):
inline = False
_hash = None
_specificity = None
def __init__(self, completeName='*'):
if not isinstance(completeName, tuple):
completeName = (None, '*', completeName)
self.completeName = completeName
def _updateHash(self):
self._hash = hash((self.fullName, self.specificity(), self.qualifiers))
def __hash__(self):
if self._hash is None:
return object.__hash__(self)
else:
return self._hash
def getNSPrefix(self):
return self.completeName[0]
nsPrefix = property(getNSPrefix)
def getName(self):
return self.completeName[2]
name = property(getName)
def getNamespace(self):
return self.completeName[1]
namespace = property(getNamespace)
def getFullName(self):
return self.completeName[1:3]
fullName = property(getFullName)
def __repr__(self):
strArgs = (self.__class__.__name__,)+self.specificity()+(self.asString(),)
return '<%s %d:%d:%d:%d %s >' % strArgs
def __str__(self):
return self.asString()
def __cmp__(self, other):
result = cmp(self.specificity(), other.specificity())
if result != 0:
return result
result = cmp(self.fullName, other.fullName)
if result != 0:
return result
result = cmp(self.qualifiers, other.qualifiers)
return result
def specificity(self):
if self._specificity is None:
self._specificity = self._calcSpecificity()
return self._specificity
def _calcSpecificity(self):
"""from http://www.w3.org/TR/CSS21/cascade.html#specificity"""
hashCount = 0
qualifierCount = 0
elementCount = int(self.name != '*')
for q in self.qualifiers:
if q.isHash(): hashCount += 1
elif q.isClass(): qualifierCount += 1
elif q.isAttr(): qualifierCount += 1
elif q.isPseudo(): elementCount += 1
elif q.isCombiner():
i,h,q,e = q.selector.specificity()
hashCount += h
qualifierCount += q
elementCount += e
return self.inline, hashCount, qualifierCount, elementCount
def matches(self, element=None):
if element is None:
return False
if not element.matchesNode(self.fullName):
return False
for qualifier in self.qualifiers:
if not qualifier.matches(element):
return False
else:
return True
def asString(self):
result = []
if self.nsPrefix is not None:
result.append('%s|%s' % (self.nsPrefix, self.name))
else: result.append(self.name)
for q in self.qualifiers:
if q.isCombiner():
result.insert(0, q.asString())
else:
result.append(q.asString())
return ''.join(result)
#~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
class CSSInlineSelector(CSSSelectorBase):
inline = True
#~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
class CSSMutableSelector(CSSSelectorBase, cssParser.CSSSelectorAbstract):
qualifiers = []
def asImmutable(self):
return CSSImmutableSelector(self.completeName, [q.asImmutable() for q in self.qualifiers])
def combineSelectors(klass, selectorA, op, selectorB):
selectorB.addCombination(op, selectorA)
return selectorB
combineSelectors = classmethod(combineSelectors)
def addCombination(self, op, other):
self._addQualifier(CSSSelectorCombinationQualifier(op, other))
def addHashId(self, hashId):
self._addQualifier(CSSSelectorHashQualifier(hashId))
def addClass(self, class_):
self._addQualifier(CSSSelectorClassQualifier(class_))
def addAttribute(self, attrName):
self._addQualifier(CSSSelectorAttributeQualifier(attrName))
def addAttributeOperation(self, attrName, op, attrValue):
self._addQualifier(CSSSelectorAttributeQualifier(attrName, op, attrValue))
def addPseudo(self, name):
self._addQualifier(CSSSelectorPseudoQualifier(name))
def addPseudoFunction(self, name, params):
self._addQualifier(CSSSelectorPseudoQualifier(name, params))
#~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
def _addQualifier(self, qualifier):
if self.qualifiers:
self.qualifiers.append(qualifier)
else:
self.qualifiers = [qualifier]
#~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
class CSSImmutableSelector(CSSSelectorBase):
def __init__(self, completeName='*', qualifiers=()):
# print completeName, qualifiers
self.qualifiers = tuple(qualifiers)
CSSSelectorBase.__init__(self, completeName)
self._updateHash()
def fromSelector(klass, selector):
return klass(selector.completeName, selector.qualifiers)
fromSelector = classmethod(fromSelector)
#~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
#~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
#~ CSS Selector Qualifiers -- see CSSImmutableSelector
#~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
class CSSSelectorQualifierBase(object):
def isHash(self):
return False
def isClass(self):
return False
def isAttr(self):
return False
def isPseudo(self):
return False
def isCombiner(self):
return False
def asImmutable(self):
return self
def __str__(self):
return self.asString()
class CSSSelectorHashQualifier(CSSSelectorQualifierBase):
def __init__(self, hashId):
self.hashId = hashId
def isHash(self):
return True
def __hash__(self):
return hash((self.hashId,))
def asString(self):
return '#'+self.hashId
def matches(self, element):
return element.getIdAttr() == self.hashId
class CSSSelectorClassQualifier(CSSSelectorQualifierBase):
def __init__(self, classId):
self.classId = classId
def isClass(self):
return True
def __hash__(self):
return hash((self.classId,))
def asString(self):
return '.'+self.classId
def matches(self, element):
return self.classId in element.getClassAttr().split()
class CSSSelectorAttributeQualifier(CSSSelectorQualifierBase):
name, op, value = None, None, NotImplemented
def __init__(self, attrName, op=None, attrValue=NotImplemented):
self.name = attrName
if op is not self.op:
self.op = op
if attrValue is not self.value:
self.value = attrValue
def isAttr(self):
return True
def __hash__(self):
return hash((self.name, self.op, self.value))
def asString(self):
if self.value is NotImplemented:
return '[%s]' % (self.name,)
else: return '[%s%s%s]' % (self.name, self.op, self.value)
def matches(self, element):
op = self.op
if op is None:
return element.getAttr(self.name, NotImplemented) != NotImplemented
elif op == '=':
return self.value == element.getAttr(self.name, NotImplemented)
elif op == '~=':
return self.value in element.getAttr(self.name, '').split()
elif op == '|=':
return self.value in element.getAttr(self.name, '').split('-')
else:
raise RuntimeError("Unknown operator %r for %r" % (self.op, self))
class CSSSelectorPseudoQualifier(CSSSelectorQualifierBase):
def __init__(self, attrName, params=()):
self.name = attrName
self.params = tuple(params)
def isPseudo(self):
return True
def __hash__(self):
return hash((self.name, self.params))
def asString(self):
if self.params:
return ':'+self.name
else:
return ':%s(%s)' % (self.name, self.params)
def matches(self, element):
return element.inPseudoState(self.name, self.params)
class CSSSelectorCombinationQualifier(CSSSelectorQualifierBase):
def __init__(self, op, selector):
self.op = op
self.selector = selector
def isCombiner(self):
return True
def __hash__(self):
return hash((self.op, self.selector))
def asImmutable(self):
return self.__class__(self.op, self.selector.asImmutable())
def asString(self):
return '%s%s' % (self.selector.asString(), self.op)
def matches(self, element):
op, selector = self.op, self.selector
if op == ' ':
for parent in element.iterXMLParents():
if selector.matches(parent):
return True
else:
return False
elif op == '>':
for parent in element.iterXMLParents():
if selector.matches(parent):
return True
else:
return False
elif op == '+':
return selector.matches(element.getPreviousSibling())
#~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
#~ CSS Misc
#~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
class CSSTerminalFunction(object):
def __init__(self, name, params):
self.name = name
self.params = params
def __repr__(self):
return '<CSS function: %s(%s)>' % (self.name, ', '.join(self.params))
class CSSTerminalOperator(tuple):
def __new__(klass, *args):
return tuple.__new__(klass, args)
def __repr__(self):
return 'op' + tuple.__repr__(self)
#~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
#~ CSS Objects
#~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
class CSSDeclarations(dict):
pass
class CSSRuleset(dict):
def findCSSRulesFor(self, element, attrName):
ruleResults = []
append = ruleResults.append
for nodeFilter, declarations in self.iteritems():
if (attrName in declarations) and (nodeFilter.matches(element)):
append((nodeFilter, declarations))
ruleResults.sort()
return ruleResults
def findCSSRuleFor(self, *args, **kw):
# rule is packed in a list to differentiate from "no rule" vs "rule
# whose value evalutates as False"
return self.findCSSRulesFor(*args, **kw)[-1:]
def mergeStyles(self, styles):
" XXX Bugfix for use in PISA "
for k, v in styles.items():
if self.has_key(k) and self[k]:
self[k] = copy.copy(self[k])
self[k].update(v)
else:
self[k] = v
class CSSInlineRuleset(CSSRuleset, CSSDeclarations):
def findCSSRulesFor(self, element, attrName):
if attrName in self:
return [(CSSInlineSelector(), self)]
else:
return []
def findCSSRuleFor(self, *args, **kw):
# rule is packed in a list to differentiate from "no rule" vs "rule
# whose value evalutates as False"
return self.findCSSRulesFor(*args, **kw)[-1:]
#~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
#~ CSS Builder
#~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
class CSSBuilder(cssParser.CSSBuilderAbstract):
RulesetFactory = CSSRuleset
SelectorFactory = CSSMutableSelector
MediumSetFactory = sets.Set
DeclarationsFactory = CSSDeclarations
TermFunctionFactory = CSSTerminalFunction
TermOperatorFactory = CSSTerminalOperator
xmlnsSynonyms = {}
mediumSet = None
trackImportance = True
charset = None
def __init__(self, mediumSet=mediumSet, trackImportance=trackImportance):
self.setMediumSet(mediumSet)
self.setTrackImportance(trackImportance)
def isValidMedium(self, mediums):
if not mediums:
return False
if 'all' in mediums:
return True
mediums = self.MediumSetFactory(mediums)
return bool(self.getMediumSet().intersection(mediums))
def getMediumSet(self):
return self.mediumSet
def setMediumSet(self, mediumSet):
self.mediumSet = self.MediumSetFactory(mediumSet)
def updateMediumSet(self, mediumSet):
self.getMediumSet().update(mediumSet)
def getTrackImportance(self):
return self.trackImportance
def setTrackImportance(self, trackImportance=True):
self.trackImportance = trackImportance
#~ helpers ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
def _pushState(self):
_restoreState = self.__dict__
self.__dict__ = self.__dict__.copy()
self._restoreState = _restoreState
self.namespaces = {}
def _popState(self):
self.__dict__ = self._restoreState
def _declarations(self, declarations, DeclarationsFactory=None):
DeclarationsFactory = DeclarationsFactory or self.DeclarationsFactory
if self.trackImportance:
normal, important = [], []
for d in declarations:
if d[-1]:
important.append(d[:-1])
else: normal.append(d[:-1])
return DeclarationsFactory(normal), DeclarationsFactory(important)
else:
return DeclarationsFactory(declarations)
def _xmlnsGetSynonym(self, uri):
# Don't forget to substitute our namespace synonyms!
return self.xmlnsSynonyms.get(uri or None, uri) or None
#~ css results ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
def beginStylesheet(self):
self._pushState()
def endStylesheet(self):
self._popState()
def stylesheet(self, stylesheetElements, stylesheetImports):
# XXX Updated for PISA
if self.trackImportance:
normal, important = self.RulesetFactory(), self.RulesetFactory()
for normalStylesheet, importantStylesheet in stylesheetImports:
normal.mergeStyles(normalStylesheet)
important.mergeStyles(importantStylesheet)
for normalStyleElement, importantStyleElement in stylesheetElements:
normal.mergeStyles(normalStyleElement)
important.mergeStyles(importantStyleElement)
return normal, important
else:
result = self.RulesetFactory()
for stylesheet in stylesheetImports:
result.mergeStyles(stylesheet)
for styleElement in stylesheetElements:
result.mergeStyles(styleElement)
return result
def beginInline(self):
self._pushState()
def endInline(self):
self._popState()
def specialRules(self, declarations):
return cssSpecial.parseSpecialRules(declarations)
def inline(self, declarations):
declarations = self.specialRules(declarations)
return self._declarations(declarations, CSSInlineRuleset)
def ruleset(self, selectors, declarations):
# XXX Modified for pisa!
declarations = self.specialRules(declarations)
# XXX Modified for pisa!
if self.trackImportance:
normalDecl, importantDecl = self._declarations(declarations)
normal, important = self.RulesetFactory(), self.RulesetFactory()
for s in selectors:
s = s.asImmutable()
if normalDecl:
normal[s] = normalDecl
if importantDecl:
important[s] = importantDecl
return normal, important
else:
declarations = self._declarations(declarations)
result = [(s.asImmutable(), declarations) for s in selectors]
return self.RulesetFactory(result)
#~ css namespaces ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
def resolveNamespacePrefix(self, nsPrefix, name):
if nsPrefix == '*':
return (nsPrefix, '*', name)
xmlns = self.namespaces.get(nsPrefix, None)
xmlns = self._xmlnsGetSynonym(xmlns)
return (nsPrefix, xmlns, name)
#~ css @ directives ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
def atCharset(self, charset):
self.charset = charset
def atImport(self, import_, mediums, cssParser):
if self.isValidMedium(mediums):
return cssParser.parseExternal(import_)
return None
def atNamespace(self, nsprefix, uri):
self.namespaces[nsprefix] = uri
def atMedia(self, mediums, ruleset):
if self.isValidMedium(mediums):
return ruleset
return None
def atPage(self, page, pseudopage, declarations):
return self.ruleset([self.selector('*')], declarations)
def atFontFace(self, declarations):
return self.ruleset([self.selector('*')], declarations)
def atIdent(self, atIdent, cssParser, src):
return src, NotImplemented
#~ css selectors ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
def selector(self, name):
return self.SelectorFactory(name)
def combineSelectors(self, selectorA, op, selectorB):
return self.SelectorFactory.combineSelectors(selectorA, op, selectorB)
#~ css declarations ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
def property(self, name, value, important=False):
if self.trackImportance:
return (name, value, important)
else:
return (name, value)
def combineTerms(self, termA, op, termB):
if op in (',', ' '):
if isinstance(termA, list):
termA.append(termB)
return termA
else:
return [termA, termB]
elif op is None and termB is None:
return [termA]
else:
if isinstance(termA, list):
# Bind these "closer" than the list operators -- i.e. work on
# the (recursively) last element of the list
termA[-1] = self.combineTerms(termA[-1], op, termB)
return termA
else:
return self.TermOperatorFactory(termA, op, termB)
def termIdent(self, value):
return value
def termNumber(self, value, units=None):
if units:
return value, units
else:
return value
def termRGB(self, value):
return value
def termURI(self, value):
return value
def termString(self, value):
return value
def termUnicodeRange(self, value):
return value
def termFunction(self, name, value):
return self.TermFunctionFactory(name, value)
def termUnknown(self, src):
return src, NotImplemented
#~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
#~ CSS Parser -- finally!
#~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
class CSSParser(cssParser.CSSParser):
CSSBuilderFactory = CSSBuilder
def __init__(self, cssBuilder=None, create=True, **kw):
if not cssBuilder and create:
assert cssBuilder is None
cssBuilder = self.createCSSBuilder(**kw)
cssParser.CSSParser.__init__(self, cssBuilder)
def createCSSBuilder(self, **kw):
return self.CSSBuilderFactory(**kw)
def parseExternal(self, cssResourceName):
if os.path.isfile(cssResourceName):
cssFile = file(cssResourceName, 'r')
return self.parseFile(cssFile, True)
else:
raise RuntimeError("Cannot resolve external CSS file: \"%s\"" % cssResourceName)