554 lines
18 KiB
Text
554 lines
18 KiB
Text
Quick and dirty 2to3 port of sgmllib from Python 2.
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From https://pypi.org/project/sgmllib3k/
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Index: feedparser/sgmllib.py
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--- feedparser/sgmllib.py.orig
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+++ feedparser/sgmllib.py
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@@ -0,0 +1,547 @@
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+"""A parser for SGML, using the derived class as a static DTD."""
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+
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+# XXX This only supports those SGML features used by HTML.
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+
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+# XXX There should be a way to distinguish between PCDATA (parsed
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+# character data -- the normal case), RCDATA (replaceable character
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+# data -- only char and entity references and end tags are special)
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+# and CDATA (character data -- only end tags are special). RCDATA is
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+# not supported at all.
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+
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+import _markupbase
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+import re
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+
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+__all__ = ["SGMLParser", "SGMLParseError"]
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+
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+# Regular expressions used for parsing
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+
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+interesting = re.compile('[&<]')
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+incomplete = re.compile('&([a-zA-Z][a-zA-Z0-9]*|#[0-9]*)?|'
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+ '<([a-zA-Z][^<>]*|'
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+ '/([a-zA-Z][^<>]*)?|'
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+ '![^<>]*)?')
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+
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+entityref = re.compile('&([a-zA-Z][-.a-zA-Z0-9]*)[^a-zA-Z0-9]')
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+charref = re.compile('&#([0-9]+)[^0-9]')
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+
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+starttagopen = re.compile('<[>a-zA-Z]')
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+shorttagopen = re.compile('<[a-zA-Z][-.a-zA-Z0-9]*/')
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+shorttag = re.compile('<([a-zA-Z][-.a-zA-Z0-9]*)/([^/]*)/')
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+piclose = re.compile('>')
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+endbracket = re.compile('[<>]')
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+tagfind = re.compile('[a-zA-Z][-_.a-zA-Z0-9]*')
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+attrfind = re.compile(
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+ r'\s*([a-zA-Z_][-:.a-zA-Z_0-9]*)(\s*=\s*'
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+ r'(\'[^\']*\'|"[^"]*"|[][\-a-zA-Z0-9./,:;+*%?!&$\(\)_#=~\'"@]*))?')
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+
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+
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+class SGMLParseError(RuntimeError):
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+ """Exception raised for all parse errors."""
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+ pass
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+
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+
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+# SGML parser base class -- find tags and call handler functions.
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+# Usage: p = SGMLParser(); p.feed(data); ...; p.close().
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+# The dtd is defined by deriving a class which defines methods
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+# with special names to handle tags: start_foo and end_foo to handle
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+# <foo> and </foo>, respectively, or do_foo to handle <foo> by itself.
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+# (Tags are converted to lower case for this purpose.) The data
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+# between tags is passed to the parser by calling self.handle_data()
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+# with some data as argument (the data may be split up in arbitrary
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+# chunks). Entity references are passed by calling
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+# self.handle_entityref() with the entity reference as argument.
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+
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+class SGMLParser(_markupbase.ParserBase):
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+ # Definition of entities -- derived classes may override
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+ entity_or_charref = re.compile('&(?:'
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+ '([a-zA-Z][-.a-zA-Z0-9]*)|#([0-9]+)'
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+ ')(;?)')
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+
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+ def __init__(self, verbose=0):
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+ """Initialize and reset this instance."""
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+ self.verbose = verbose
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+ self.reset()
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+
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+ def reset(self):
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+ """Reset this instance. Loses all unprocessed data."""
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+ self.__starttag_text = None
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+ self.rawdata = ''
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+ self.stack = []
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+ self.lasttag = '???'
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+ self.nomoretags = 0
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+ self.literal = 0
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+ _markupbase.ParserBase.reset(self)
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+
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+ def setnomoretags(self):
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+ """Enter literal mode (CDATA) till EOF.
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+
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+ Intended for derived classes only.
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+ """
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+ self.nomoretags = self.literal = 1
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+
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+ def setliteral(self, *args):
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+ """Enter literal mode (CDATA).
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+
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+ Intended for derived classes only.
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+ """
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+ self.literal = 1
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+
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+ def feed(self, data):
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+ """Feed some data to the parser.
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+
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+ Call this as often as you want, with as little or as much text
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+ as you want (may include '\n'). (This just saves the text,
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+ all the processing is done by goahead().)
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+ """
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+
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+ self.rawdata = self.rawdata + data
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+ self.goahead(0)
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+
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+ def close(self):
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+ """Handle the remaining data."""
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+ self.goahead(1)
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+
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+ def error(self, message):
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+ raise SGMLParseError(message)
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+
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+ # Internal -- handle data as far as reasonable. May leave state
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+ # and data to be processed by a subsequent call. If 'end' is
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+ # true, force handling all data as if followed by EOF marker.
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+ def goahead(self, end):
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+ rawdata = self.rawdata
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+ i = 0
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+ n = len(rawdata)
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+ while i < n:
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+ if self.nomoretags:
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+ self.handle_data(rawdata[i:n])
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+ i = n
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+ break
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+ match = interesting.search(rawdata, i)
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+ if match: j = match.start()
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+ else: j = n
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+ if i < j:
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+ self.handle_data(rawdata[i:j])
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+ i = j
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+ if i == n: break
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+ if rawdata[i] == '<':
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+ if starttagopen.match(rawdata, i):
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+ if self.literal:
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+ self.handle_data(rawdata[i])
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+ i = i+1
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+ continue
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+ k = self.parse_starttag(i)
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+ if k < 0: break
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+ i = k
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+ continue
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+ if rawdata.startswith("</", i):
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+ k = self.parse_endtag(i)
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+ if k < 0: break
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+ i = k
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+ self.literal = 0
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+ continue
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+ if self.literal:
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+ if n > (i + 1):
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+ self.handle_data("<")
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+ i = i+1
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+ else:
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+ # incomplete
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+ break
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+ continue
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+ if rawdata.startswith("<!--", i):
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+ # Strictly speaking, a comment is --.*--
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+ # within a declaration tag <!...>.
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+ # This should be removed,
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+ # and comments handled only in parse_declaration.
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+ k = self.parse_comment(i)
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+ if k < 0: break
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+ i = k
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+ continue
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+ if rawdata.startswith("<?", i):
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+ k = self.parse_pi(i)
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+ if k < 0: break
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+ i = i+k
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+ continue
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+ if rawdata.startswith("<!", i):
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+ # This is some sort of declaration; in "HTML as
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+ # deployed," this should only be the document type
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+ # declaration ("<!DOCTYPE html...>").
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+ k = self.parse_declaration(i)
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+ if k < 0: break
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+ i = k
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+ continue
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+ elif rawdata[i] == '&':
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+ if self.literal:
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+ self.handle_data(rawdata[i])
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+ i = i+1
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+ continue
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+ match = charref.match(rawdata, i)
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+ if match:
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+ name = match.group(1)
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+ self.handle_charref(name)
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+ i = match.end(0)
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+ if rawdata[i-1] != ';': i = i-1
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+ continue
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+ match = entityref.match(rawdata, i)
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+ if match:
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+ name = match.group(1)
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+ self.handle_entityref(name)
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+ i = match.end(0)
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+ if rawdata[i-1] != ';': i = i-1
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+ continue
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+ else:
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+ self.error('neither < nor & ??')
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+ # We get here only if incomplete matches but
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+ # nothing else
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+ match = incomplete.match(rawdata, i)
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+ if not match:
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+ self.handle_data(rawdata[i])
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+ i = i+1
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+ continue
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+ j = match.end(0)
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+ if j == n:
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+ break # Really incomplete
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+ self.handle_data(rawdata[i:j])
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+ i = j
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+ # end while
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+ if end and i < n:
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+ self.handle_data(rawdata[i:n])
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+ i = n
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+ self.rawdata = rawdata[i:]
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+ # XXX if end: check for empty stack
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+
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+ # Extensions for the DOCTYPE scanner:
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+ _decl_otherchars = '='
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+
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+ # Internal -- parse processing instr, return length or -1 if not terminated
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+ def parse_pi(self, i):
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+ rawdata = self.rawdata
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+ if rawdata[i:i+2] != '<?':
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+ self.error('unexpected call to parse_pi()')
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+ match = piclose.search(rawdata, i+2)
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+ if not match:
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+ return -1
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+ j = match.start(0)
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+ self.handle_pi(rawdata[i+2: j])
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+ j = match.end(0)
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+ return j-i
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+
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+ def get_starttag_text(self):
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+ return self.__starttag_text
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+
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+ # Internal -- handle starttag, return length or -1 if not terminated
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+ def parse_starttag(self, i):
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+ self.__starttag_text = None
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+ start_pos = i
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+ rawdata = self.rawdata
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+ if shorttagopen.match(rawdata, i):
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+ # SGML shorthand: <tag/data/ == <tag>data</tag>
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+ # XXX Can data contain &... (entity or char refs)?
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+ # XXX Can data contain < or > (tag characters)?
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+ # XXX Can there be whitespace before the first /?
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+ match = shorttag.match(rawdata, i)
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+ if not match:
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+ return -1
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+ tag, data = match.group(1, 2)
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+ self.__starttag_text = '<%s/' % tag
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+ tag = tag.lower()
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+ k = match.end(0)
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+ self.finish_shorttag(tag, data)
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+ self.__starttag_text = rawdata[start_pos:match.end(1) + 1]
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+ return k
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+ # XXX The following should skip matching quotes (' or ")
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+ # As a shortcut way to exit, this isn't so bad, but shouldn't
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+ # be used to locate the actual end of the start tag since the
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+ # < or > characters may be embedded in an attribute value.
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+ match = endbracket.search(rawdata, i+1)
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+ if not match:
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+ return -1
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+ j = match.start(0)
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+ # Now parse the data between i+1 and j into a tag and attrs
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+ attrs = []
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+ if rawdata[i:i+2] == '<>':
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+ # SGML shorthand: <> == <last open tag seen>
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+ k = j
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+ tag = self.lasttag
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+ else:
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+ match = tagfind.match(rawdata, i+1)
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+ if not match:
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+ self.error('unexpected call to parse_starttag')
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+ k = match.end(0)
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+ tag = rawdata[i+1:k].lower()
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+ self.lasttag = tag
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+ while k < j:
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+ match = attrfind.match(rawdata, k)
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+ if not match: break
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+ attrname, rest, attrvalue = match.group(1, 2, 3)
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+ if not rest:
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+ attrvalue = attrname
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+ else:
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+ if (attrvalue[:1] == "'" == attrvalue[-1:] or
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+ attrvalue[:1] == '"' == attrvalue[-1:]):
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+ # strip quotes
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+ attrvalue = attrvalue[1:-1]
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+ attrvalue = self.entity_or_charref.sub(
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+ self._convert_ref, attrvalue)
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+ attrs.append((attrname.lower(), attrvalue))
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+ k = match.end(0)
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+ if rawdata[j] == '>':
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+ j = j+1
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+ self.__starttag_text = rawdata[start_pos:j]
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+ self.finish_starttag(tag, attrs)
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+ return j
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+
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+ # Internal -- convert entity or character reference
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+ def _convert_ref(self, match):
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+ if match.group(2):
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+ return self.convert_charref(match.group(2)) or \
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+ '&#%s%s' % match.groups()[1:]
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+ elif match.group(3):
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+ return self.convert_entityref(match.group(1)) or \
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+ '&%s;' % match.group(1)
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+ else:
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+ return '&%s' % match.group(1)
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+
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+ # Internal -- parse endtag
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+ def parse_endtag(self, i):
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+ rawdata = self.rawdata
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+ match = endbracket.search(rawdata, i+1)
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+ if not match:
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+ return -1
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+ j = match.start(0)
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+ tag = rawdata[i+2:j].strip().lower()
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+ if rawdata[j] == '>':
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+ j = j+1
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+ self.finish_endtag(tag)
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+ return j
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+
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+ # Internal -- finish parsing of <tag/data/ (same as <tag>data</tag>)
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+ def finish_shorttag(self, tag, data):
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+ self.finish_starttag(tag, [])
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+ self.handle_data(data)
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+ self.finish_endtag(tag)
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+
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+ # Internal -- finish processing of start tag
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+ # Return -1 for unknown tag, 0 for open-only tag, 1 for balanced tag
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+ def finish_starttag(self, tag, attrs):
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+ try:
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+ method = getattr(self, 'start_' + tag)
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+ except AttributeError:
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+ try:
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+ method = getattr(self, 'do_' + tag)
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+ except AttributeError:
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+ self.unknown_starttag(tag, attrs)
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+ return -1
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+ else:
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+ self.handle_starttag(tag, method, attrs)
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+ return 0
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+ else:
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+ self.stack.append(tag)
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+ self.handle_starttag(tag, method, attrs)
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+ return 1
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+
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+ # Internal -- finish processing of end tag
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+ def finish_endtag(self, tag):
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+ if not tag:
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+ found = len(self.stack) - 1
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+ if found < 0:
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+ self.unknown_endtag(tag)
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+ return
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+ else:
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+ if tag not in self.stack:
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+ try:
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+ method = getattr(self, 'end_' + tag)
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+ except AttributeError:
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+ self.unknown_endtag(tag)
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+ else:
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+ self.report_unbalanced(tag)
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+ return
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+ found = len(self.stack)
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+ for i in range(found):
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+ if self.stack[i] == tag: found = i
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+ while len(self.stack) > found:
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+ tag = self.stack[-1]
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+ try:
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+ method = getattr(self, 'end_' + tag)
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+ except AttributeError:
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+ method = None
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+ if method:
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+ self.handle_endtag(tag, method)
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+ else:
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+ self.unknown_endtag(tag)
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+ del self.stack[-1]
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+
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+ # Overridable -- handle start tag
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+ def handle_starttag(self, tag, method, attrs):
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+ method(attrs)
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+
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+ # Overridable -- handle end tag
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+ def handle_endtag(self, tag, method):
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+ method()
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+
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+ # Example -- report an unbalanced </...> tag.
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+ def report_unbalanced(self, tag):
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+ if self.verbose:
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+ print('*** Unbalanced </' + tag + '>')
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+ print('*** Stack:', self.stack)
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+
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+ def convert_charref(self, name):
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+ """Convert character reference, may be overridden."""
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+ try:
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+ n = int(name)
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+ except ValueError:
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+ return
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+ if not 0 <= n <= 127:
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+ return
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+ return self.convert_codepoint(n)
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+
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+ def convert_codepoint(self, codepoint):
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+ return chr(codepoint)
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+
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+ def handle_charref(self, name):
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+ """Handle character reference, no need to override."""
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+ replacement = self.convert_charref(name)
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+ if replacement is None:
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+ self.unknown_charref(name)
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+ else:
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+ self.handle_data(replacement)
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+
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+ # Definition of entities -- derived classes may override
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+ entitydefs = \
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+ {'lt': '<', 'gt': '>', 'amp': '&', 'quot': '"', 'apos': '\''}
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+
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+ def convert_entityref(self, name):
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+ """Convert entity references.
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+
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+ As an alternative to overriding this method; one can tailor the
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+ results by setting up the self.entitydefs mapping appropriately.
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+ """
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+ table = self.entitydefs
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+ if name in table:
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+ return table[name]
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+ else:
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+ return
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+
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+ def handle_entityref(self, name):
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+ """Handle entity references, no need to override."""
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+ replacement = self.convert_entityref(name)
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+ if replacement is None:
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+ self.unknown_entityref(name)
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+ else:
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+ self.handle_data(replacement)
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+
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+ # Example -- handle data, should be overridden
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+ def handle_data(self, data):
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+ pass
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+
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+ # Example -- handle comment, could be overridden
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+ def handle_comment(self, data):
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+ pass
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+
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+ # Example -- handle declaration, could be overridden
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+ def handle_decl(self, decl):
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+ pass
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+
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+ # Example -- handle processing instruction, could be overridden
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+ def handle_pi(self, data):
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+ pass
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+
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+ # To be overridden -- handlers for unknown objects
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+ def unknown_starttag(self, tag, attrs): pass
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+ def unknown_endtag(self, tag): pass
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+ def unknown_charref(self, ref): pass
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+ def unknown_entityref(self, ref): pass
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+
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+
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+class TestSGMLParser(SGMLParser):
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+
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+ def __init__(self, verbose=0):
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+ self.testdata = ""
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+ SGMLParser.__init__(self, verbose)
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+
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+ def handle_data(self, data):
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+ self.testdata = self.testdata + data
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+ if len(repr(self.testdata)) >= 70:
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+ self.flush()
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+
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+ def flush(self):
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+ data = self.testdata
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+ if data:
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+ self.testdata = ""
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+ print('data:', repr(data))
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+
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+ def handle_comment(self, data):
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+ self.flush()
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+ r = repr(data)
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+ if len(r) > 68:
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+ r = r[:32] + '...' + r[-32:]
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+ print('comment:', r)
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+
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+ def unknown_starttag(self, tag, attrs):
|
|
+ self.flush()
|
|
+ if not attrs:
|
|
+ print('start tag: <' + tag + '>')
|
|
+ else:
|
|
+ print('start tag: <' + tag, end=' ')
|
|
+ for name, value in attrs:
|
|
+ print(name + '=' + '"' + value + '"', end=' ')
|
|
+ print('>')
|
|
+
|
|
+ def unknown_endtag(self, tag):
|
|
+ self.flush()
|
|
+ print('end tag: </' + tag + '>')
|
|
+
|
|
+ def unknown_entityref(self, ref):
|
|
+ self.flush()
|
|
+ print('*** unknown entity ref: &' + ref + ';')
|
|
+
|
|
+ def unknown_charref(self, ref):
|
|
+ self.flush()
|
|
+ print('*** unknown char ref: &#' + ref + ';')
|
|
+
|
|
+ def unknown_decl(self, data):
|
|
+ self.flush()
|
|
+ print('*** unknown decl: [' + data + ']')
|
|
+
|
|
+ def close(self):
|
|
+ SGMLParser.close(self)
|
|
+ self.flush()
|
|
+
|
|
+
|
|
+def test(args = None):
|
|
+ import sys
|
|
+
|
|
+ if args is None:
|
|
+ args = sys.argv[1:]
|
|
+
|
|
+ if args and args[0] == '-s':
|
|
+ args = args[1:]
|
|
+ klass = SGMLParser
|
|
+ else:
|
|
+ klass = TestSGMLParser
|
|
+
|
|
+ if args:
|
|
+ file = args[0]
|
|
+ else:
|
|
+ file = 'test.html'
|
|
+
|
|
+ if file == '-':
|
|
+ f = sys.stdin
|
|
+ else:
|
|
+ try:
|
|
+ f = open(file, 'r')
|
|
+ except IOError as msg:
|
|
+ print(file, ":", msg)
|
|
+ sys.exit(1)
|
|
+
|
|
+ data = f.read()
|
|
+ if f is not sys.stdin:
|
|
+ f.close()
|
|
+
|
|
+ x = klass()
|
|
+ for c in data:
|
|
+ x.feed(c)
|
|
+ x.close()
|
|
+
|
|
+
|
|
+if __name__ == '__main__':
|
|
+ test()
|