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9d63b6ae56
Python2 had old-style classes (no "(object)"), and new style classes (with "object"). Under Py3 this is a noop, so let's drop it to make the code a bit shorter.
107 lines
4.5 KiB
Python
107 lines
4.5 KiB
Python
#!/usr/bin/env python
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# vim:fileencoding=utf-8
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__license__ = 'GPL v3'
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__copyright__ = '2014, Kovid Goyal <kovid at kovidgoyal.net>'
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from tinycss.css21 import CSS21Parser
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from tinycss.parsing import remove_whitespace, split_on_comma, ParseError
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from polyglot.builtins import error_message
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class MediaQuery:
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__slots__ = 'media_type', 'expressions', 'negated'
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def __init__(self, media_type='all', expressions=(), negated=False):
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self.media_type = media_type
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self.expressions = expressions
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self.negated = negated
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def __repr__(self):
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return '<MediaQuery type=%s negated=%s expressions=%s>' % (
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self.media_type, self.negated, self.expressions)
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def __eq__(self, other):
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return self.media_type == getattr(other, 'media_type', None) and \
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self.negated == getattr(other, 'negated', None) and \
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self.expressions == getattr(other, 'expressions', None)
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class MalformedExpression(Exception):
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def __init__(self, tok, msg):
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Exception.__init__(self, msg)
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self.tok = tok
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class CSSMedia3Parser(CSS21Parser):
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''' Parse media queries as defined by the CSS 3 media module '''
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def parse_media(self, tokens, errors):
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if not tokens:
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return [MediaQuery('all')]
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queries = []
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for part in split_on_comma(remove_whitespace(tokens)):
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negated = False
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media_type = None
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expressions = []
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try:
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for i, tok in enumerate(part):
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if i == 0 and tok.type == 'IDENT':
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val = tok.value.lower()
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if val == 'only':
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continue # ignore leading ONLY
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if val == 'not':
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negated = True
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continue
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if media_type is None and tok.type == 'IDENT':
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media_type = tok.value
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continue
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elif media_type is None:
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media_type = 'all'
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if tok.type == 'IDENT' and tok.value.lower() == 'and':
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continue
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if not tok.is_container:
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raise MalformedExpression(tok, 'expected a media expression not a %s' % tok.type)
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if tok.type != '(':
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raise MalformedExpression(tok, 'media expressions must be in parentheses not %s' % tok.type)
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content = remove_whitespace(tok.content)
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if len(content) == 0:
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raise MalformedExpression(tok, 'media expressions cannot be empty')
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if content[0].type != 'IDENT':
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raise MalformedExpression(content[0], 'expected a media feature not a %s' % tok.type)
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media_feature, expr = content[0].value, None
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if len(content) > 1:
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if len(content) < 3:
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raise MalformedExpression(content[1], 'malformed media feature definition')
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if content[1].type != ':':
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raise MalformedExpression(content[1], 'expected a :')
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expr = content[2:]
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if len(expr) == 1:
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expr = expr[0]
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elif len(expr) == 3 and (expr[0].type, expr[1].type, expr[1].value, expr[2].type) == (
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'INTEGER', 'DELIM', '/', 'INTEGER'):
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# This should really be moved into token_data, but
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# since RATIO is not part of CSS 2.1 and does not
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# occur anywhere else, we special case it here.
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r = expr[0]
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r.value = (expr[0].value, expr[2].value)
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r.type = 'RATIO'
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r._as_css = expr[0]._as_css + expr[1]._as_css + expr[2]._as_css
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expr = r
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else:
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raise MalformedExpression(expr[0], 'malformed media feature definition')
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expressions.append((media_feature, expr))
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except MalformedExpression as err:
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errors.append(ParseError(err.tok, error_message(err)))
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media_type, negated, expressions = 'all', True, ()
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queries.append(MediaQuery(media_type or 'all', expressions=tuple(expressions), negated=negated))
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return queries
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