| Fred Drake | 68f8a80 | 2001-09-24 20:01:28 +0000 | [diff] [blame] | 1 | """Shared support for scanning document type declarations in HTML and XHTML.""" |
| 2 | |
| 3 | import re |
| 4 | import string |
| 5 | |
| 6 | _declname_match = re.compile(r'[a-zA-Z][-_.a-zA-Z0-9]*\s*').match |
| 7 | _declstringlit_match = re.compile(r'(\'[^\']*\'|"[^"]*")\s*').match |
| 8 | |
| 9 | del re |
| 10 | |
| 11 | |
| 12 | class ParserBase: |
| 13 | """Parser base class which provides some common support methods used |
| 14 | by the SGML/HTML and XHTML parsers.""" |
| 15 | |
| Fred Drake | 5445f07 | 2001-10-26 18:02:28 +0000 | [diff] [blame] | 16 | def __init__(self): |
| 17 | if self.__class__ is ParserBase: |
| 18 | raise RuntimeError( |
| 19 | "markupbase.ParserBase must be subclassed") |
| 20 | |
| 21 | def error(self, message): |
| 22 | raise NotImplementedError( |
| 23 | "subclasses of ParserBase must override error()") |
| 24 | |
| Fred Drake | 68f8a80 | 2001-09-24 20:01:28 +0000 | [diff] [blame] | 25 | def reset(self): |
| 26 | self.lineno = 1 |
| 27 | self.offset = 0 |
| 28 | |
| 29 | def getpos(self): |
| 30 | """Return current line number and offset.""" |
| 31 | return self.lineno, self.offset |
| 32 | |
| 33 | # Internal -- update line number and offset. This should be |
| 34 | # called for each piece of data exactly once, in order -- in other |
| 35 | # words the concatenation of all the input strings to this |
| 36 | # function should be exactly the entire input. |
| 37 | def updatepos(self, i, j): |
| 38 | if i >= j: |
| 39 | return j |
| 40 | rawdata = self.rawdata |
| 41 | nlines = string.count(rawdata, "\n", i, j) |
| 42 | if nlines: |
| 43 | self.lineno = self.lineno + nlines |
| 44 | pos = string.rindex(rawdata, "\n", i, j) # Should not fail |
| 45 | self.offset = j-(pos+1) |
| 46 | else: |
| 47 | self.offset = self.offset + j-i |
| 48 | return j |
| 49 | |
| 50 | _decl_otherchars = '' |
| 51 | |
| 52 | # Internal -- parse declaration (for use by subclasses). |
| 53 | def parse_declaration(self, i): |
| 54 | # This is some sort of declaration; in "HTML as |
| 55 | # deployed," this should only be the document type |
| 56 | # declaration ("<!DOCTYPE html...>"). |
| 57 | rawdata = self.rawdata |
| Fred Drake | 68f8a80 | 2001-09-24 20:01:28 +0000 | [diff] [blame] | 58 | j = i + 2 |
| 59 | assert rawdata[i:j] == "<!", "unexpected call to parse_declaration" |
| 60 | if rawdata[j:j+1] in ("-", ""): |
| 61 | # Start of comment followed by buffer boundary, |
| 62 | # or just a buffer boundary. |
| 63 | return -1 |
| 64 | # in practice, this should look like: ((name|stringlit) S*)+ '>' |
| 65 | n = len(rawdata) |
| 66 | decltype, j = self._scan_name(j, i) |
| 67 | if j < 0: |
| 68 | return j |
| 69 | if decltype == "doctype": |
| 70 | self._decl_otherchars = '' |
| 71 | while j < n: |
| 72 | c = rawdata[j] |
| 73 | if c == ">": |
| 74 | # end of declaration syntax |
| 75 | data = rawdata[i+2:j] |
| 76 | if decltype == "doctype": |
| 77 | self.handle_decl(data) |
| 78 | else: |
| 79 | self.unknown_decl(data) |
| 80 | return j + 1 |
| 81 | if c in "\"'": |
| 82 | m = _declstringlit_match(rawdata, j) |
| 83 | if not m: |
| 84 | return -1 # incomplete |
| 85 | j = m.end() |
| 86 | elif c in "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ": |
| 87 | name, j = self._scan_name(j, i) |
| 88 | elif c in self._decl_otherchars: |
| 89 | j = j + 1 |
| 90 | elif c == "[": |
| 91 | if decltype == "doctype": |
| 92 | j = self._parse_doctype_subset(j + 1, i) |
| 93 | else: |
| 94 | self.error("unexpected '[' char in declaration") |
| 95 | else: |
| 96 | self.error( |
| 97 | "unexpected %s char in declaration" % `rawdata[j]`) |
| 98 | if j < 0: |
| 99 | return j |
| 100 | return -1 # incomplete |
| 101 | |
| 102 | # Internal -- scan past the internal subset in a <!DOCTYPE declaration, |
| 103 | # returning the index just past any whitespace following the trailing ']'. |
| 104 | def _parse_doctype_subset(self, i, declstartpos): |
| 105 | rawdata = self.rawdata |
| 106 | n = len(rawdata) |
| 107 | j = i |
| 108 | while j < n: |
| 109 | c = rawdata[j] |
| 110 | if c == "<": |
| 111 | s = rawdata[j:j+2] |
| 112 | if s == "<": |
| 113 | # end of buffer; incomplete |
| 114 | return -1 |
| 115 | if s != "<!": |
| 116 | self.updatepos(declstartpos, j + 1) |
| 117 | self.error("unexpected char in internal subset (in %s)" |
| 118 | % `s`) |
| 119 | if (j + 2) == n: |
| 120 | # end of buffer; incomplete |
| 121 | return -1 |
| 122 | if (j + 4) > n: |
| 123 | # end of buffer; incomplete |
| 124 | return -1 |
| 125 | if rawdata[j:j+4] == "<!--": |
| 126 | j = self.parse_comment(j, report=0) |
| 127 | if j < 0: |
| 128 | return j |
| 129 | continue |
| 130 | name, j = self._scan_name(j + 2, declstartpos) |
| 131 | if j == -1: |
| 132 | return -1 |
| 133 | if name not in ("attlist", "element", "entity", "notation"): |
| 134 | self.updatepos(declstartpos, j + 2) |
| 135 | self.error( |
| 136 | "unknown declaration %s in internal subset" % `name`) |
| 137 | # handle the individual names |
| 138 | meth = getattr(self, "_parse_doctype_" + name) |
| 139 | j = meth(j, declstartpos) |
| 140 | if j < 0: |
| 141 | return j |
| 142 | elif c == "%": |
| 143 | # parameter entity reference |
| 144 | if (j + 1) == n: |
| 145 | # end of buffer; incomplete |
| 146 | return -1 |
| 147 | s, j = self._scan_name(j + 1, declstartpos) |
| 148 | if j < 0: |
| 149 | return j |
| 150 | if rawdata[j] == ";": |
| 151 | j = j + 1 |
| 152 | elif c == "]": |
| 153 | j = j + 1 |
| 154 | while j < n and rawdata[j] in string.whitespace: |
| 155 | j = j + 1 |
| 156 | if j < n: |
| 157 | if rawdata[j] == ">": |
| 158 | return j |
| 159 | self.updatepos(declstartpos, j) |
| 160 | self.error("unexpected char after internal subset") |
| 161 | else: |
| 162 | return -1 |
| 163 | elif c in string.whitespace: |
| 164 | j = j + 1 |
| 165 | else: |
| 166 | self.updatepos(declstartpos, j) |
| 167 | self.error("unexpected char %s in internal subset" % `c`) |
| 168 | # end of buffer reached |
| 169 | return -1 |
| 170 | |
| 171 | # Internal -- scan past <!ELEMENT declarations |
| 172 | def _parse_doctype_element(self, i, declstartpos): |
| Fred Drake | 68f8a80 | 2001-09-24 20:01:28 +0000 | [diff] [blame] | 173 | name, j = self._scan_name(i, declstartpos) |
| 174 | if j == -1: |
| 175 | return -1 |
| 176 | # style content model; just skip until '>' |
| Fred Drake | 5445f07 | 2001-10-26 18:02:28 +0000 | [diff] [blame] | 177 | rawdata = self.rawdata |
| Fred Drake | 68f8a80 | 2001-09-24 20:01:28 +0000 | [diff] [blame] | 178 | if '>' in rawdata[j:]: |
| 179 | return string.find(rawdata, ">", j) + 1 |
| 180 | return -1 |
| 181 | |
| 182 | # Internal -- scan past <!ATTLIST declarations |
| 183 | def _parse_doctype_attlist(self, i, declstartpos): |
| 184 | rawdata = self.rawdata |
| 185 | name, j = self._scan_name(i, declstartpos) |
| 186 | c = rawdata[j:j+1] |
| 187 | if c == "": |
| 188 | return -1 |
| 189 | if c == ">": |
| 190 | return j + 1 |
| 191 | while 1: |
| 192 | # scan a series of attribute descriptions; simplified: |
| 193 | # name type [value] [#constraint] |
| 194 | name, j = self._scan_name(j, declstartpos) |
| 195 | if j < 0: |
| 196 | return j |
| 197 | c = rawdata[j:j+1] |
| 198 | if c == "": |
| 199 | return -1 |
| 200 | if c == "(": |
| 201 | # an enumerated type; look for ')' |
| 202 | if ")" in rawdata[j:]: |
| 203 | j = string.find(rawdata, ")", j) + 1 |
| 204 | else: |
| 205 | return -1 |
| 206 | while rawdata[j:j+1] in string.whitespace: |
| 207 | j = j + 1 |
| 208 | if not rawdata[j:]: |
| 209 | # end of buffer, incomplete |
| 210 | return -1 |
| 211 | else: |
| 212 | name, j = self._scan_name(j, declstartpos) |
| 213 | c = rawdata[j:j+1] |
| 214 | if not c: |
| 215 | return -1 |
| 216 | if c in "'\"": |
| 217 | m = _declstringlit_match(rawdata, j) |
| 218 | if m: |
| 219 | j = m.end() |
| 220 | else: |
| 221 | return -1 |
| 222 | c = rawdata[j:j+1] |
| 223 | if not c: |
| 224 | return -1 |
| 225 | if c == "#": |
| 226 | if rawdata[j:] == "#": |
| 227 | # end of buffer |
| 228 | return -1 |
| 229 | name, j = self._scan_name(j + 1, declstartpos) |
| 230 | if j < 0: |
| 231 | return j |
| 232 | c = rawdata[j:j+1] |
| 233 | if not c: |
| 234 | return -1 |
| 235 | if c == '>': |
| 236 | # all done |
| 237 | return j + 1 |
| 238 | |
| 239 | # Internal -- scan past <!NOTATION declarations |
| 240 | def _parse_doctype_notation(self, i, declstartpos): |
| 241 | name, j = self._scan_name(i, declstartpos) |
| 242 | if j < 0: |
| 243 | return j |
| 244 | rawdata = self.rawdata |
| 245 | while 1: |
| 246 | c = rawdata[j:j+1] |
| 247 | if not c: |
| 248 | # end of buffer; incomplete |
| 249 | return -1 |
| 250 | if c == '>': |
| 251 | return j + 1 |
| 252 | if c in "'\"": |
| 253 | m = _declstringlit_match(rawdata, j) |
| 254 | if not m: |
| 255 | return -1 |
| 256 | j = m.end() |
| 257 | else: |
| 258 | name, j = self._scan_name(j, declstartpos) |
| 259 | if j < 0: |
| 260 | return j |
| 261 | |
| 262 | # Internal -- scan past <!ENTITY declarations |
| 263 | def _parse_doctype_entity(self, i, declstartpos): |
| 264 | rawdata = self.rawdata |
| 265 | if rawdata[i:i+1] == "%": |
| 266 | j = i + 1 |
| 267 | while 1: |
| 268 | c = rawdata[j:j+1] |
| 269 | if not c: |
| 270 | return -1 |
| 271 | if c in string.whitespace: |
| 272 | j = j + 1 |
| 273 | else: |
| 274 | break |
| 275 | else: |
| 276 | j = i |
| 277 | name, j = self._scan_name(j, declstartpos) |
| 278 | if j < 0: |
| 279 | return j |
| 280 | while 1: |
| 281 | c = self.rawdata[j:j+1] |
| 282 | if not c: |
| 283 | return -1 |
| 284 | if c in "'\"": |
| 285 | m = _declstringlit_match(rawdata, j) |
| 286 | if m: |
| 287 | j = m.end() |
| 288 | else: |
| 289 | return -1 # incomplete |
| 290 | elif c == ">": |
| 291 | return j + 1 |
| 292 | else: |
| 293 | name, j = self._scan_name(j, declstartpos) |
| 294 | if j < 0: |
| 295 | return j |
| 296 | |
| 297 | # Internal -- scan a name token and the new position and the token, or |
| 298 | # return -1 if we've reached the end of the buffer. |
| 299 | def _scan_name(self, i, declstartpos): |
| 300 | rawdata = self.rawdata |
| 301 | n = len(rawdata) |
| 302 | if i == n: |
| 303 | return None, -1 |
| 304 | m = _declname_match(rawdata, i) |
| 305 | if m: |
| 306 | s = m.group() |
| 307 | name = s.strip() |
| 308 | if (i + len(s)) == n: |
| 309 | return None, -1 # end of buffer |
| Fred Drake | 1cffd5c | 2001-09-24 20:04:29 +0000 | [diff] [blame] | 310 | return string.lower(name), m.end() |
| Fred Drake | 68f8a80 | 2001-09-24 20:01:28 +0000 | [diff] [blame] | 311 | else: |
| 312 | self.updatepos(declstartpos, i) |
| Fred Drake | 3d32be1 | 2001-10-13 15:59:47 +0000 | [diff] [blame] | 313 | self.error("expected name token") |
| Fred Drake | 5445f07 | 2001-10-26 18:02:28 +0000 | [diff] [blame] | 314 | |
| 315 | # To be overridden -- handlers for unknown objects |
| 316 | def unknown_decl(self, data): |
| 317 | pass |