from __future__ import absolute_import, division, unicode_literals
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import re
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from . import base
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from ..constants import rcdataElements, spaceCharacters
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spaceCharacters = "".join(spaceCharacters)
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SPACES_REGEX = re.compile("[%s]+" % spaceCharacters)
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class Filter(base.Filter):
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"""Collapses whitespace except in pre, textarea, and script elements"""
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spacePreserveElements = frozenset(["pre", "textarea"] + list(rcdataElements))
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def __iter__(self):
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preserve = 0
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for token in base.Filter.__iter__(self):
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type = token["type"]
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if type == "StartTag" \
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and (preserve or token["name"] in self.spacePreserveElements):
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preserve += 1
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elif type == "EndTag" and preserve:
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preserve -= 1
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elif not preserve and type == "SpaceCharacters" and token["data"]:
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# Test on token["data"] above to not introduce spaces where there were not
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token["data"] = " "
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elif not preserve and type == "Characters":
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token["data"] = collapse_spaces(token["data"])
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yield token
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def collapse_spaces(text):
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return SPACES_REGEX.sub(' ', text)
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