📄 markupbase.py
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"""Shared support for scanning document type declarations in HTML and XHTML."""import reimport string_declname_match = re.compile(r'[a-zA-Z][-_.a-zA-Z0-9]*\s*').match_declstringlit_match = re.compile(r'(\'[^\']*\'|"[^"]*")\s*').matchdel reclass ParserBase: """Parser base class which provides some common support methods used by the SGML/HTML and XHTML parsers.""" def __init__(self): if self.__class__ is ParserBase: raise RuntimeError( "markupbase.ParserBase must be subclassed") def error(self, message): raise NotImplementedError( "subclasses of ParserBase must override error()") def reset(self): self.lineno = 1 self.offset = 0 def getpos(self): """Return current line number and offset.""" return self.lineno, self.offset # Internal -- update line number and offset. This should be # called for each piece of data exactly once, in order -- in other # words the concatenation of all the input strings to this # function should be exactly the entire input. def updatepos(self, i, j): if i >= j: return j rawdata = self.rawdata nlines = string.count(rawdata, "\n", i, j) if nlines: self.lineno = self.lineno + nlines pos = string.rindex(rawdata, "\n", i, j) # Should not fail self.offset = j-(pos+1) else: self.offset = self.offset + j-i return j _decl_otherchars = '' # Internal -- parse declaration (for use by subclasses). def parse_declaration(self, i): # This is some sort of declaration; in "HTML as # deployed," this should only be the document type # declaration ("<!DOCTYPE html...>"). rawdata = self.rawdata j = i + 2 assert rawdata[i:j] == "<!", "unexpected call to parse_declaration" if rawdata[j:j+1] in ("-", ""): # Start of comment followed by buffer boundary, # or just a buffer boundary. return -1 # in practice, this should look like: ((name|stringlit) S*)+ '>' n = len(rawdata) decltype, j = self._scan_name(j, i) if j < 0: return j if decltype == "doctype": self._decl_otherchars = '' while j < n: c = rawdata[j] if c == ">": # end of declaration syntax data = rawdata[i+2:j] if decltype == "doctype": self.handle_decl(data) else: self.unknown_decl(data) return j + 1 if c in "\"'": m = _declstringlit_match(rawdata, j) if not m: return -1 # incomplete j = m.end() elif c in "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ": name, j = self._scan_name(j, i) elif c in self._decl_otherchars: j = j + 1 elif c == "[": if decltype == "doctype": j = self._parse_doctype_subset(j + 1, i) else: self.error("unexpected '[' char in declaration") else: self.error( "unexpected %s char in declaration" % `rawdata[j]`) if j < 0: return j return -1 # incomplete # Internal -- scan past the internal subset in a <!DOCTYPE declaration, # returning the index just past any whitespace following the trailing ']'. def _parse_doctype_subset(self, i, declstartpos): rawdata = self.rawdata n = len(rawdata) j = i while j < n: c = rawdata[j] if c == "<": s = rawdata[j:j+2] if s == "<": # end of buffer; incomplete return -1 if s != "<!": self.updatepos(declstartpos, j + 1) self.error("unexpected char in internal subset (in %s)" % `s`) if (j + 2) == n: # end of buffer; incomplete return -1 if (j + 4) > n: # end of buffer; incomplete return -1 if rawdata[j:j+4] == "<!--": j = self.parse_comment(j, report=0) if j < 0: return j continue name, j = self._scan_name(j + 2, declstartpos) if j == -1: return -1 if name not in ("attlist", "element", "entity", "notation"): self.updatepos(declstartpos, j + 2) self.error( "unknown declaration %s in internal subset" % `name`) # handle the individual names meth = getattr(self, "_parse_doctype_" + name) j = meth(j, declstartpos) if j < 0: return j elif c == "%": # parameter entity reference if (j + 1) == n: # end of buffer; incomplete return -1 s, j = self._scan_name(j + 1, declstartpos) if j < 0: return j if rawdata[j] == ";": j = j + 1 elif c == "]": j = j + 1 while j < n and rawdata[j] in string.whitespace: j = j + 1 if j < n: if rawdata[j] == ">": return j self.updatepos(declstartpos, j) self.error("unexpected char after internal subset") else: return -1 elif c in string.whitespace: j = j + 1 else: self.updatepos(declstartpos, j) self.error("unexpected char %s in internal subset" % `c`) # end of buffer reached return -1 # Internal -- scan past <!ELEMENT declarations def _parse_doctype_element(self, i, declstartpos): name, j = self._scan_name(i, declstartpos) if j == -1: return -1 # style content model; just skip until '>' rawdata = self.rawdata if '>' in rawdata[j:]: return string.find(rawdata, ">", j) + 1 return -1 # Internal -- scan past <!ATTLIST declarations def _parse_doctype_attlist(self, i, declstartpos): rawdata = self.rawdata name, j = self._scan_name(i, declstartpos) c = rawdata[j:j+1] if c == "": return -1 if c == ">": return j + 1 while 1: # scan a series of attribute descriptions; simplified: # name type [value] [#constraint] name, j = self._scan_name(j, declstartpos) if j < 0: return j c = rawdata[j:j+1] if c == "": return -1 if c == "(": # an enumerated type; look for ')' if ")" in rawdata[j:]: j = string.find(rawdata, ")", j) + 1 else: return -1 while rawdata[j:j+1] in string.whitespace: j = j + 1 if not rawdata[j:]: # end of buffer, incomplete return -1 else: name, j = self._scan_name(j, declstartpos) c = rawdata[j:j+1] if not c: return -1 if c in "'\"": m = _declstringlit_match(rawdata, j) if m: j = m.end() else: return -1 c = rawdata[j:j+1] if not c: return -1 if c == "#": if rawdata[j:] == "#": # end of buffer return -1 name, j = self._scan_name(j + 1, declstartpos) if j < 0: return j c = rawdata[j:j+1] if not c: return -1 if c == '>': # all done return j + 1 # Internal -- scan past <!NOTATION declarations def _parse_doctype_notation(self, i, declstartpos): name, j = self._scan_name(i, declstartpos) if j < 0: return j rawdata = self.rawdata while 1: c = rawdata[j:j+1] if not c: # end of buffer; incomplete return -1 if c == '>': return j + 1 if c in "'\"": m = _declstringlit_match(rawdata, j) if not m: return -1 j = m.end() else: name, j = self._scan_name(j, declstartpos) if j < 0: return j # Internal -- scan past <!ENTITY declarations def _parse_doctype_entity(self, i, declstartpos): rawdata = self.rawdata if rawdata[i:i+1] == "%": j = i + 1 while 1: c = rawdata[j:j+1] if not c: return -1 if c in string.whitespace: j = j + 1 else: break else: j = i name, j = self._scan_name(j, declstartpos) if j < 0: return j while 1: c = self.rawdata[j:j+1] if not c: return -1 if c in "'\"": m = _declstringlit_match(rawdata, j) if m: j = m.end() else: return -1 # incomplete elif c == ">": return j + 1 else: name, j = self._scan_name(j, declstartpos) if j < 0: return j # Internal -- scan a name token and the new position and the token, or # return -1 if we've reached the end of the buffer. def _scan_name(self, i, declstartpos): rawdata = self.rawdata n = len(rawdata) if i == n: return None, -1 m = _declname_match(rawdata, i) if m: s = m.group() name = s.strip() if (i + len(s)) == n: return None, -1 # end of buffer return string.lower(name), m.end() else: self.updatepos(declstartpos, i) self.error("expected name token") # To be overridden -- handlers for unknown objects def unknown_decl(self, data): pass⌨️ 快捷键说明
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