calibre/src/cssutils/util.py
Kovid Goyal fc934f1f66 IGN:...
2008-09-19 10:01:15 -07:00

854 lines
28 KiB
Python

"""base classes and helper functions for css and stylesheets packages
"""
__all__ = []
__docformat__ = 'restructuredtext'
__version__ = '$Id: util.py 1453 2008-09-08 20:57:19Z cthedot $'
import codecs
from itertools import ifilter
import types
import urllib2
import xml.dom
from helper import normalize
import tokenize2
import cssutils
import encutils
class Base(object):
"""
Base class for most CSS and StyleSheets classes
**Superceded by Base2 which is used for new seq handling class.**
See cssutils.util.Base2
Contains helper methods for inheriting classes helping parsing
``_normalize`` is static as used by Preferences.
"""
__tokenizer2 = tokenize2.Tokenizer()
_log = cssutils.log
_prods = tokenize2.CSSProductions
# for more on shorthand properties see
# http://www.dustindiaz.com/css-shorthand/
# format: shorthand: [(propname, mandatorycheck?)*]
_SHORTHANDPROPERTIES = {
u'background': [],
u'background-position': [],
u'border': [],
u'border-left': [],
u'border-right': [],
u'border-top': [],
u'border-bottom': [],
#u'border-color': [], # list or single but same values
#u'border-style': [], # list or single but same values
#u'border-width': [], # list or single but same values
u'cue': [],
u'font': [],
u'list-style': [],
#u'margin': [], # list or single but same values
u'outline': [],
#u'padding': [], # list or single but same values
u'pause': []
}
@staticmethod
def _normalize(x):
"""
normalizes x, namely:
- remove any \ before non unicode sequences (0-9a-zA-Z) so for
x=="c\olor\" return "color" (unicode escape sequences should have
been resolved by the tokenizer already)
- lowercase
"""
return normalize(x)
def _checkReadonly(self):
"raises xml.dom.NoModificationAllowedErr if rule/... is readonly"
if hasattr(self, '_readonly') and self._readonly:
raise xml.dom.NoModificationAllowedErr(
u'%s is readonly.' % self.__class__)
return True
return False
def _splitNamespacesOff(self, text_namespaces_tuple):
"""
returns tuple (text, dict-of-namespaces) or if no namespaces are
in cssText returns (cssText, {})
used in Selector, SelectorList, CSSStyleRule, CSSMediaRule and
CSSStyleSheet
"""
if isinstance(text_namespaces_tuple, tuple):
return text_namespaces_tuple[0], _SimpleNamespaces(self._log,
text_namespaces_tuple[1])
else:
return text_namespaces_tuple, _SimpleNamespaces(log=self._log)
def _tokenize2(self, textortokens):
"""
returns tokens of textortokens which may already be tokens in which
case simply returns input
"""
if not textortokens:
return None
elif isinstance(textortokens, basestring):
# needs to be tokenized
return self.__tokenizer2.tokenize(
textortokens)
elif types.GeneratorType == type(textortokens):
# already tokenized
return textortokens
elif isinstance(textortokens, tuple):
# a single token (like a comment)
return [textortokens]
else:
# already tokenized but return generator
return (x for x in textortokens)
def _nexttoken(self, tokenizer, default=None):
"returns next token in generator tokenizer or the default value"
try:
return tokenizer.next()
except (StopIteration, AttributeError):
return default
def _type(self, token):
"returns type of Tokenizer token"
if token:
return token[0]
else:
return None
def _tokenvalue(self, token, normalize=False):
"returns value of Tokenizer token"
if token and normalize:
return Base._normalize(token[1])
elif token:
return token[1]
else:
return None
def _stringtokenvalue(self, token):
"""
for STRING returns the actual content without surrounding "" or ''
and without respective escapes, e.g.::
"with \" char" => with " char
"""
if token:
value = token[1]
return value.replace('\\'+value[0], value[0])[1:-1]
else:
return None
def _uritokenvalue(self, token):
"""
for URI returns the actual content without surrounding url()
or url(""), url('') and without respective escapes, e.g.::
url("\"") => "
"""
if token:
value = token[1][4:-1].strip()
if value and (value[0] in '\'"') and (value[0] == value[-1]):
# a string "..." or '...'
value = value.replace('\\'+value[0], value[0])[1:-1]
return value
else:
return None
def _tokensupto2(self,
tokenizer,
starttoken=None,
blockstartonly=False, # {
blockendonly=False, # }
mediaendonly=False,
importmediaqueryendonly=False, # ; or STRING
mediaqueryendonly=False, # { or STRING
semicolon=False, # ;
propertynameendonly=False, # :
propertyvalueendonly=False, # ! ; }
propertypriorityendonly=False, # ; }
selectorattendonly=False, # ]
funcendonly=False, # )
listseponly=False, # ,
separateEnd=False # returns (resulttokens, endtoken)
):
"""
returns tokens upto end of atrule and end index
end is defined by parameters, might be ; } ) or other
default looks for ending "}" and ";"
"""
ends = u';}'
endtypes = ()
brace = bracket = parant = 0 # {}, [], ()
if blockstartonly: # {
ends = u'{'
brace = -1 # set to 0 with first {
elif blockendonly: # }
ends = u'}'
brace = 1
elif mediaendonly: # }
ends = u'}'
brace = 1 # rules } and mediarules }
elif importmediaqueryendonly:
# end of mediaquery which may be ; or STRING
ends = u';'
endtypes = ('STRING',)
elif mediaqueryendonly:
# end of mediaquery which may be { or STRING
# special case, see below
ends = u'{'
brace = -1 # set to 0 with first {
endtypes = ('STRING',)
elif semicolon:
ends = u';'
elif propertynameendonly: # : and ; in case of an error
ends = u':;'
elif propertyvalueendonly: # ; or !important
ends = u';!'
elif propertypriorityendonly: # ;
ends = u';'
elif selectorattendonly: # ]
ends = u']'
if starttoken and self._tokenvalue(starttoken) == u'[':
bracket = 1
elif funcendonly: # )
ends = u')'
parant = 1
elif listseponly: # ,
ends = u','
resulttokens = []
if starttoken:
resulttokens.append(starttoken)
if tokenizer:
for token in tokenizer:
typ, val, line, col = token
if 'EOF' == typ:
resulttokens.append(token)
break
if u'{' == val:
brace += 1
elif u'}' == val:
brace -= 1
elif u'[' == val:
bracket += 1
elif u']' == val:
bracket -= 1
# function( or single (
elif u'(' == val or \
Base._prods.FUNCTION == typ:
parant += 1
elif u')' == val:
parant -= 1
resulttokens.append(token)
if (brace == bracket == parant == 0) and (
val in ends or typ in endtypes):
break
elif mediaqueryendonly and brace == -1 and (
bracket == parant == 0) and typ in endtypes:
# mediaqueryendonly with STRING
break
if separateEnd:
# TODO: use this method as generator, then this makes sense
if resulttokens:
return resulttokens[:-1], resulttokens[-1]
else:
return resulttokens, None
else:
return resulttokens
def _valuestr(self, t):
"""
returns string value of t (t may be a string, a list of token tuples
or a single tuple in format (type, value, line, col).
Mainly used to get a string value of t for error messages.
"""
if not t:
return u''
elif isinstance(t, basestring):
return t
else:
return u''.join([x[1] for x in t])
def _adddefaultproductions(self, productions, new=None):
"""
adds default productions if not already present, used by
_parse only
each production should return the next expected token
normaly a name like "uri" or "EOF"
some have no expectation like S or COMMENT, so simply return
the current value of self.__expected
"""
def ATKEYWORD(expected, seq, token, tokenizer=None):
"default impl for unexpected @rule"
if expected != 'EOF':
# TODO: parentStyleSheet=self
rule = cssutils.css.CSSUnknownRule()
rule.cssText = self._tokensupto2(tokenizer, token)
if rule.wellformed:
seq.append(rule)
return expected
else:
new['wellformed'] = False
self._log.error(u'Expected EOF.', token=token)
return expected
def COMMENT(expected, seq, token, tokenizer=None):
"default implementation for COMMENT token adds CSSCommentRule"
seq.append(cssutils.css.CSSComment([token]))
return expected
def S(expected, seq, token, tokenizer=None):
"default implementation for S token, does nothing"
return expected
def EOF(expected=None, seq=None, token=None, tokenizer=None):
"default implementation for EOF token"
return 'EOF'
p = {'ATKEYWORD': ATKEYWORD,
'COMMENT': COMMENT,
'S': S,
'EOF': EOF # only available if fullsheet
}
p.update(productions)
return p
def _parse(self, expected, seq, tokenizer, productions, default=None,
new=None, initialtoken=None):
"""
puts parsed tokens in seq by calling a production with
(seq, tokenizer, token)
expected
a name what token or value is expected next, e.g. 'uri'
seq
to add rules etc to
tokenizer
call tokenizer.next() to get next token
productions
callbacks {tokentype: callback}
default
default callback if tokentype not in productions
new
used to init default productions
initialtoken
will be used together with tokenizer running 1st this token
and then all tokens in tokenizer
returns (wellformed, expected) which the last prod might have set
"""
wellformed = True
if initialtoken:
# add initialtoken to tokenizer
def tokens():
"Build new tokenizer including initialtoken"
yield initialtoken
for item in tokenizer:
yield item
fulltokenizer = (t for t in tokens())
else:
fulltokenizer = tokenizer
if fulltokenizer:
prods = self._adddefaultproductions(productions, new)
for token in fulltokenizer:
p = prods.get(token[0], default)
if p:
expected = p(expected, seq, token, tokenizer)
else:
wellformed = False
self._log.error(u'Unexpected token (%s, %s, %s, %s)' % token)
return wellformed, expected
class Base2(Base):
"""
Base class for new seq handling, used by Selector for now only
"""
def __init__(self):
self._seq = Seq()
def _setSeq(self, newseq):
"""
sets newseq and makes it readonly
"""
newseq._readonly = True
self._seq = newseq
seq = property(lambda self: self._seq, doc="seq for most classes")
def _tempSeq(self, readonly=False):
"get a writeable Seq() which is added later"
return Seq(readonly=readonly)
def _adddefaultproductions(self, productions, new=None):
"""
adds default productions if not already present, used by
_parse only
each production should return the next expected token
normaly a name like "uri" or "EOF"
some have no expectation like S or COMMENT, so simply return
the current value of self.__expected
"""
def ATKEYWORD(expected, seq, token, tokenizer=None):
"default impl for unexpected @rule"
if expected != 'EOF':
# TODO: parentStyleSheet=self
rule = cssutils.css.CSSUnknownRule()
rule.cssText = self._tokensupto2(tokenizer, token)
if rule.wellformed:
seq.append(rule, cssutils.css.CSSRule.UNKNOWN_RULE,
line=token[2], col=token[3])
return expected
else:
new['wellformed'] = False
self._log.error(u'Expected EOF.', token=token)
return expected
def COMMENT(expected, seq, token, tokenizer=None):
"default impl, adds CSSCommentRule if not token == EOF"
if expected == 'EOF':
new['wellformed'] = False
self._log.error(u'Expected EOF but found comment.', token=token)
seq.append(cssutils.css.CSSComment([token]), 'COMMENT')
return expected
def S(expected, seq, token, tokenizer=None):
"default impl, does nothing if not token == EOF"
if expected == 'EOF':
new['wellformed'] = False
self._log.error(u'Expected EOF but found whitespace.', token=token)
return expected
def EOF(expected=None, seq=None, token=None, tokenizer=None):
"default implementation for EOF token"
return 'EOF'
defaultproductions = {'ATKEYWORD': ATKEYWORD,
'COMMENT': COMMENT,
'S': S,
'EOF': EOF # only available if fullsheet
}
defaultproductions.update(productions)
return defaultproductions
class Seq(object):
"""
property seq of Base2 inheriting classes, holds a list of Item objects.
used only by Selector for now
is normally readonly, only writable during parsing
"""
def __init__(self, readonly=True):
"""
only way to write to a Seq is to initialize it with new items
each itemtuple has (value, type, line) where line is optional
"""
self._seq = []
self._readonly = readonly
def __delitem__(self, i):
del self._seq[i]
def __getitem__(self, i):
return self._seq[i]
def __setitem__(self, i, (val, typ, line, col)):
self._seq[i] = Item(val, typ, line, col)
def __iter__(self):
return iter(self._seq)
def __len__(self):
return len(self._seq)
def append(self, val, typ, line=None, col=None):
"if not readonly add new Item()"
if self._readonly:
raise AttributeError('Seq is readonly.')
else:
self._seq.append(Item(val, typ, line, col))
def appendItem(self, item):
"if not readonly add item which must be an Item"
if self._readonly:
raise AttributeError('Seq is readonly.')
else:
self._seq.append(item)
def replace(self, index=-1, val=None, typ=None, line=None, col=None):
"""
if not readonly replace Item at index with new Item or
simply replace value or type
"""
if self._readonly:
raise AttributeError('Seq is readonly.')
else:
self._seq[index] = Item(val, typ, line, col)
def appendToVal(self, val=None, index=-1):
"""
if not readonly append to Item's value at index
"""
if self._readonly:
raise AttributeError('Seq is readonly.')
else:
old = self._seq[index]
self._seq[index] = Item(old.value + val, old.type,
old.line, old.col)
def __repr__(self):
"returns a repr same as a list of tuples of (value, type)"
return u'cssutils.%s.%s([\n %s])' % (self.__module__,
self.__class__.__name__,
u',\n '.join([u'%r' % item for item in self._seq]
))
def __str__(self):
vals = []
for v in self:
if isinstance(v.value, basestring):
vals.append(v.value)
elif type(v) == tuple:
vals.append(v.value[1])
else:
vals.append(str(v))
return "<cssutils.%s.%s object length=%r valuestring=%r at 0x%x>" % (
self.__module__, self.__class__.__name__, len(self),
u''.join(vals), id(self))
class Item(object):
"""
an item in the seq list of classes (successor to tuple items in old seq)
each item has attributes:
type
a sematic type like "element", "attribute"
value
the actual value which may be a string, number etc or an instance
of e.g. a CSSComment
*line*
**NOT IMPLEMENTED YET, may contain the line in the source later**
"""
def __init__(self, value, type, line=None, col=None):
self.__value = value
self.__type = type
self.__line = line
self.__col = col
type = property(lambda self: self.__type)
value = property(lambda self: self.__value)
line = property(lambda self: self.__line)
col = property(lambda self: self.__col)
def __repr__(self):
return "%s.%s(value=%r, type=%r, line=%r, col=%r)" % (
self.__module__, self.__class__.__name__,
self.__value, self.__type, self.__line, self.__col)
class ListSeq(object):
"""
(EXPERIMENTAL)
A base class used for list classes like css.SelectorList or
stylesheets.MediaList
adds list like behaviour running on inhering class' property ``seq``
- item in x => bool
- len(x) => integer
- get, set and del x[i]
- for item in x
- append(item)
some methods must be overwritten in inheriting class
"""
def __init__(self):
self.seq = [] # does not need to use ``Seq`` as simple list only
def __contains__(self, item):
return item in self.seq
def __delitem__(self, index):
del self.seq[index]
def __getitem__(self, index):
return self.seq[index]
def __iter__(self):
def gen():
for x in self.seq:
yield x
return gen()
def __len__(self):
return len(self.seq)
def __setitem__(self, index, item):
"must be overwritten"
raise NotImplementedError
def append(self, item):
"must be overwritten"
raise NotImplementedError
class _Namespaces(object):
"""
A dictionary like wrapper for @namespace rules used in a CSSStyleSheet.
Works on effective namespaces, so e.g. if::
@namespace p1 "uri";
@namespace p2 "uri";
only the second rule is effective and kept.
namespaces
a dictionary {prefix: namespaceURI} containing the effective namespaces
only. These are the latest set in the CSSStyleSheet.
parentStyleSheet
the parent CSSStyleSheet
"""
def __init__(self, parentStyleSheet, log=None, *args):
"no initial values are set, only the relevant sheet is"
self.parentStyleSheet = parentStyleSheet
self._log = log
def __contains__(self, prefix):
return prefix in self.namespaces
def __delitem__(self, prefix):
"""deletes CSSNamespaceRule(s) with rule.prefix == prefix
prefix '' and None are handled the same
"""
if not prefix:
prefix = u''
delrule = self.__findrule(prefix)
for i, rule in enumerate(ifilter(lambda r: r.type == r.NAMESPACE_RULE,
self.parentStyleSheet.cssRules)):
if rule == delrule:
self.parentStyleSheet.deleteRule(i)
return
self._log.error('Prefix %r not found.' % prefix,
error=xml.dom.NamespaceErr)
def __getitem__(self, prefix):
try:
return self.namespaces[prefix]
except KeyError, e:
self._log.error('Prefix %r not found.' % prefix,
error=xml.dom.NamespaceErr)
def __iter__(self):
return self.namespaces.__iter__()
def __len__(self):
return len(self.namespaces)
def __setitem__(self, prefix, namespaceURI):
"replaces prefix or sets new rule, may raise NoModificationAllowedErr"
if not prefix:
prefix = u'' # None or ''
rule = self.__findrule(prefix)
if not rule:
self.parentStyleSheet.insertRule(cssutils.css.CSSNamespaceRule(
prefix=prefix,
namespaceURI=namespaceURI),
inOrder=True)
else:
if prefix in self.namespaces:
rule.namespaceURI = namespaceURI # raises NoModificationAllowedErr
if namespaceURI in self.namespaces.values():
rule.prefix = prefix
def __findrule(self, prefix):
# returns namespace rule where prefix == key
for rule in ifilter(lambda r: r.type == r.NAMESPACE_RULE,
reversed(self.parentStyleSheet.cssRules)):
if rule.prefix == prefix:
return rule
def __getNamespaces(self):
namespaces = {}
for rule in ifilter(lambda r: r.type == r.NAMESPACE_RULE,
reversed(self.parentStyleSheet.cssRules)):
if rule.namespaceURI not in namespaces.values():
namespaces[rule.prefix] = rule.namespaceURI
return namespaces
namespaces = property(__getNamespaces,
doc=u'Holds only effective @namespace rules in self.parentStyleSheets'
'@namespace rules.')
def get(self, prefix, default):
return self.namespaces.get(prefix, default)
def items(self):
return self.namespaces.items()
def keys(self):
return self.namespaces.keys()
def values(self):
return self.namespaces.values()
def prefixForNamespaceURI(self, namespaceURI):
"""
returns effective prefix for given namespaceURI or raises IndexError
if this cannot be found"""
for prefix, uri in self.namespaces.items():
if uri == namespaceURI:
return prefix
raise IndexError(u'NamespaceURI %r not found.' % namespaceURI)
def __str__(self):
return u"<cssutils.util.%s object parentStyleSheet=%r at 0x%x>" % (
self.__class__.__name__, str(self.parentStyleSheet), id(self))
class _SimpleNamespaces(_Namespaces):
"""
namespaces used in objects like Selector as long as they are not connected
to a CSSStyleSheet
"""
def __init__(self, log=None, *args):
"""init"""
super(_SimpleNamespaces, self).__init__(parentStyleSheet=None, log=log)
self.__namespaces = dict(*args)
def __setitem__(self, prefix, namespaceURI):
self.__namespaces[prefix] = namespaceURI
namespaces = property(lambda self: self.__namespaces,
doc=u'Dict Wrapper for self.sheets @namespace rules.')
def __str__(self):
return u"<cssutils.util.%s object namespaces=%r at 0x%x>" % (
self.__class__.__name__, self.namespaces, id(self))
def __repr__(self):
return u"cssutils.util.%s(%r)" % (self.__class__.__name__,
self.namespaces)
def _defaultFetcher(url):
"""Retrieve data from ``url``. cssutils default implementation of fetch
URL function.
Returns ``(encoding, string)`` or ``None``
"""
try:
res = urllib2.urlopen(url)
except OSError, e:
# e.g if file URL and not found
cssutils.log.warn(e, error=OSError)
except (OSError, ValueError), e:
# invalid url, e.g. "1"
cssutils.log.warn(u'ValueError, %s' % e.message, error=ValueError)
except urllib2.HTTPError, e:
# http error, e.g. 404, e can be raised
cssutils.log.warn(u'HTTPError opening url=%r: %s %s' %
(url, e.code, e.msg), error=e)
except urllib2.URLError, e:
# URLError like mailto: or other IO errors, e can be raised
cssutils.log.warn(u'URLError, %s' % e.reason, error=e)
else:
if res:
mimeType, encoding = encutils.getHTTPInfo(res)
if mimeType != u'text/css':
cssutils.log.error(u'Expected "text/css" mime type for url=%r but found: %r' %
(url, mimeType), error=ValueError)
return encoding, res.read()
def _readUrl(url, fetcher=None, overrideEncoding=None, parentEncoding=None):
"""
Read cssText from url and decode it using all relevant methods (HTTP
header, BOM, @charset). Returns
- encoding used to decode text (which is needed to set encoding of
stylesheet properly)
- type of encoding (how it was retrieved, see list below)
- decodedCssText
``fetcher``
see cssutils.registerFetchUrl for details
``overrideEncoding``
If given this encoding is used and all other encoding information is
ignored (HTTP, BOM etc)
``parentEncoding``
Encoding of parent stylesheet (while e.g. reading @import references sheets)
or document if available.
Priority or encoding information
--------------------------------
**cssutils only**: 0. overrideEncoding
1. An HTTP "charset" parameter in a "Content-Type" field (or similar parameters in other protocols)
2. BOM and/or @charset (see below)
3. <link charset=""> or other metadata from the linking mechanism (if any)
4. charset of referring style sheet or document (if any)
5. Assume UTF-8
"""
enctype = None
if not fetcher:
fetcher = _defaultFetcher
r = fetcher(url)
if r and len(r) == 2 and r[1] is not None:
httpEncoding, content = r
if overrideEncoding:
enctype = 0 # 0. override encoding
encoding = overrideEncoding
elif httpEncoding:
enctype = 1 # 1. HTTP
encoding = httpEncoding
else:
# check content
contentEncoding, explicit = cssutils.codec.detectencoding_str(content)
if explicit:
enctype = 2 # 2. BOM/@charset: explicitly
encoding = contentEncoding
elif parentEncoding:
enctype = 4 # 4. parent stylesheet or document
# may also be None in which case 5. is used in next step anyway
encoding = parentEncoding
else:
enctype = 5 # 5. assume UTF-8
encoding = 'utf-8'
try:
# encoding may still be wrong if encoding *is lying*!
if content is not None:
decodedCssText = codecs.lookup("css")[1](content, encoding=encoding)[0]
else:
decodedCssText = None
except UnicodeDecodeError, e:
cssutils.log.warn(e, neverraise=True)
decodedCssText = None
return encoding, enctype, decodedCssText
else:
return None, None, None