from __future__ import absolute_import, division, unicode_literals
from . import base
[docs]class Filter(base.Filter):
"""Removes optional tags from the token stream"""
def slider(self):
previous1 = previous2 = None
for token in self.source:
if previous1 is not None:
yield previous2, previous1, token
previous2 = previous1
previous1 = token
if previous1 is not None:
yield previous2, previous1, None
def __iter__(self):
for previous, token, next in self.slider():
type = token["type"]
if type == "StartTag":
if (token["data"] or
not self.is_optional_start(token["name"], previous, next)):
yield token
elif type == "EndTag":
if not self.is_optional_end(token["name"], next):
yield token
else:
yield token
def is_optional_start(self, tagname, previous, next):
type = next and next["type"] or None
if tagname in 'html':
# An html element's start tag may be omitted if the first thing
# inside the html element is not a space character or a comment.
return type not in ("Comment", "SpaceCharacters")
elif tagname == 'head':
# A head element's start tag may be omitted if the first thing
# inside the head element is an element.
# XXX: we also omit the start tag if the head element is empty
if type in ("StartTag", "EmptyTag"):
return True
elif type == "EndTag":
return next["name"] == "head"
elif tagname == 'body':
# A body element's start tag may be omitted if the first thing
# inside the body element is not a space character or a comment,
# except if the first thing inside the body element is a script
# or style element and the node immediately preceding the body
# element is a head element whose end tag has been omitted.
if type in ("Comment", "SpaceCharacters"):
return False
elif type == "StartTag":
# XXX: we do not look at the preceding event, so we never omit
# the body element's start tag if it's followed by a script or
# a style element.
return next["name"] not in ('script', 'style')
else:
return True
elif tagname == 'colgroup':
# A colgroup element's start tag may be omitted if the first thing
# inside the colgroup element is a col element, and if the element
# is not immediately preceded by another colgroup element whose
# end tag has been omitted.
if type in ("StartTag", "EmptyTag"):
# XXX: we do not look at the preceding event, so instead we never
# omit the colgroup element's end tag when it is immediately
# followed by another colgroup element. See is_optional_end.
return next["name"] == "col"
else:
return False
elif tagname == 'tbody':
# A tbody element's start tag may be omitted if the first thing
# inside the tbody element is a tr element, and if the element is
# not immediately preceded by a tbody, thead, or tfoot element
# whose end tag has been omitted.
if type == "StartTag":
# omit the thead and tfoot elements' end tag when they are
# immediately followed by a tbody element. See is_optional_end.
if previous and previous['type'] == 'EndTag' and \
previous['name'] in ('tbody', 'thead', 'tfoot'):
return False
return next["name"] == 'tr'
else:
return False
return False
def is_optional_end(self, tagname, next):
type = next and next["type"] or None
if tagname in ('html', 'head', 'body'):
# An html element's end tag may be omitted if the html element
# is not immediately followed by a space character or a comment.
return type not in ("Comment", "SpaceCharacters")
elif tagname in ('li', 'optgroup', 'tr'):
# A li element's end tag may be omitted if the li element is
# immediately followed by another li element or if there is
# no more content in the parent element.
# An optgroup element's end tag may be omitted if the optgroup
# element is immediately followed by another optgroup element,
# or if there is no more content in the parent element.
# A tr element's end tag may be omitted if the tr element is
# immediately followed by another tr element, or if there is
# no more content in the parent element.
if type == "StartTag":
return next["name"] == tagname
else:
return type == "EndTag" or type is None
elif tagname in ('dt', 'dd'):
# A dt element's end tag may be omitted if the dt element is
# immediately followed by another dt element or a dd element.
# A dd element's end tag may be omitted if the dd element is
# immediately followed by another dd element or a dt element,
# or if there is no more content in the parent element.
if type == "StartTag":
return next["name"] in ('dt', 'dd')
elif tagname == 'dd':
return type == "EndTag" or type is None
else:
return False
elif tagname == 'p':
# A p element's end tag may be omitted if the p element is
# immediately followed by an address, article, aside,
# blockquote, datagrid, dialog, dir, div, dl, fieldset,
# footer, form, h1, h2, h3, h4, h5, h6, header, hr, menu,
# nav, ol, p, pre, section, table, or ul, element, or if
# there is no more content in the parent element.
if type in ("StartTag", "EmptyTag"):
return next["name"] in ('address', 'article', 'aside',
'blockquote', 'datagrid', 'dialog',
'dir', 'div', 'dl', 'fieldset', 'footer',
'form', 'h1', 'h2', 'h3', 'h4', 'h5', 'h6',
'header', 'hr', 'menu', 'nav', 'ol',
'p', 'pre', 'section', 'table', 'ul')
else:
return type == "EndTag" or type is None
elif tagname == 'option':
# An option element's end tag may be omitted if the option
# element is immediately followed by another option element,
# or if it is immediately followed by an <code>optgroup</code>
# element, or if there is no more content in the parent
# element.
if type == "StartTag":
return next["name"] in ('option', 'optgroup')
else:
return type == "EndTag" or type is None
elif tagname in ('rt', 'rp'):
# An rt element's end tag may be omitted if the rt element is
# immediately followed by an rt or rp element, or if there is
# no more content in the parent element.
# An rp element's end tag may be omitted if the rp element is
# immediately followed by an rt or rp element, or if there is
# no more content in the parent element.
if type == "StartTag":
return next["name"] in ('rt', 'rp')
else:
return type == "EndTag" or type is None
elif tagname == 'colgroup':
# A colgroup element's end tag may be omitted if the colgroup
# element is not immediately followed by a space character or
# a comment.
if type in ("Comment", "SpaceCharacters"):
return False
elif type == "StartTag":
# XXX: we also look for an immediately following colgroup
# element. See is_optional_start.
return next["name"] != 'colgroup'
else:
return True
elif tagname in ('thead', 'tbody'):
# A thead element's end tag may be omitted if the thead element
# is immediately followed by a tbody or tfoot element.
# A tbody element's end tag may be omitted if the tbody element
# is immediately followed by a tbody or tfoot element, or if
# there is no more content in the parent element.
# A tfoot element's end tag may be omitted if the tfoot element
# is immediately followed by a tbody element, or if there is no
# more content in the parent element.
# XXX: we never omit the end tag when the following element is
# a tbody. See is_optional_start.
if type == "StartTag":
return next["name"] in ['tbody', 'tfoot']
elif tagname == 'tbody':
return type == "EndTag" or type is None
else:
return False
elif tagname == 'tfoot':
# A tfoot element's end tag may be omitted if the tfoot element
# is immediately followed by a tbody element, or if there is no
# more content in the parent element.
# XXX: we never omit the end tag when the following element is
# a tbody. See is_optional_start.
if type == "StartTag":
return next["name"] == 'tbody'
else:
return type == "EndTag" or type is None
elif tagname in ('td', 'th'):
# A td element's end tag may be omitted if the td element is
# immediately followed by a td or th element, or if there is
# no more content in the parent element.
# A th element's end tag may be omitted if the th element is
# immediately followed by a td or th element, or if there is
# no more content in the parent element.
if type == "StartTag":
return next["name"] in ('td', 'th')
else:
return type == "EndTag" or type is None
return False