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Long Term Support Release
1 <?php 2 3 /** 4 * Our in-house implementation of a parser. 5 * 6 * A pure PHP parser, DirectLex has absolutely no dependencies, making 7 * it a reasonably good default for PHP4. Written with efficiency in mind, 8 * it can be four times faster than HTMLPurifier_Lexer_PEARSax3, although it 9 * pales in comparison to HTMLPurifier_Lexer_DOMLex. 10 * 11 * @todo Reread XML spec and document differences. 12 */ 13 class HTMLPurifier_Lexer_DirectLex extends HTMLPurifier_Lexer 14 { 15 /** 16 * @type bool 17 */ 18 public $tracksLineNumbers = true; 19 20 /** 21 * Whitespace characters for str(c)spn. 22 * @type string 23 */ 24 protected $_whitespace = "\x20\x09\x0D\x0A"; 25 26 /** 27 * Callback function for script CDATA fudge 28 * @param array $matches, in form of array(opening tag, contents, closing tag) 29 * @return string 30 */ 31 protected function scriptCallback($matches) 32 { 33 return $matches[1] . htmlspecialchars($matches[2], ENT_COMPAT, 'UTF-8') . $matches[3]; 34 } 35 36 /** 37 * @param String $html 38 * @param HTMLPurifier_Config $config 39 * @param HTMLPurifier_Context $context 40 * @return array|HTMLPurifier_Token[] 41 */ 42 public function tokenizeHTML($html, $config, $context) 43 { 44 // special normalization for script tags without any armor 45 // our "armor" heurstic is a < sign any number of whitespaces after 46 // the first script tag 47 if ($config->get('HTML.Trusted')) { 48 $html = preg_replace_callback( 49 '#(<script[^>]*>)(\s*[^<].+?)(</script>)#si', 50 array($this, 'scriptCallback'), 51 $html 52 ); 53 } 54 55 $html = $this->normalize($html, $config, $context); 56 57 $cursor = 0; // our location in the text 58 $inside_tag = false; // whether or not we're parsing the inside of a tag 59 $array = array(); // result array 60 61 // This is also treated to mean maintain *column* numbers too 62 $maintain_line_numbers = $config->get('Core.MaintainLineNumbers'); 63 64 if ($maintain_line_numbers === null) { 65 // automatically determine line numbering by checking 66 // if error collection is on 67 $maintain_line_numbers = $config->get('Core.CollectErrors'); 68 } 69 70 if ($maintain_line_numbers) { 71 $current_line = 1; 72 $current_col = 0; 73 $length = strlen($html); 74 } else { 75 $current_line = false; 76 $current_col = false; 77 $length = false; 78 } 79 $context->register('CurrentLine', $current_line); 80 $context->register('CurrentCol', $current_col); 81 $nl = "\n"; 82 // how often to manually recalculate. This will ALWAYS be right, 83 // but it's pretty wasteful. Set to 0 to turn off 84 $synchronize_interval = $config->get('Core.DirectLexLineNumberSyncInterval'); 85 86 $e = false; 87 if ($config->get('Core.CollectErrors')) { 88 $e =& $context->get('ErrorCollector'); 89 } 90 91 // for testing synchronization 92 $loops = 0; 93 94 while (++$loops) { 95 // $cursor is either at the start of a token, or inside of 96 // a tag (i.e. there was a < immediately before it), as indicated 97 // by $inside_tag 98 99 if ($maintain_line_numbers) { 100 // $rcursor, however, is always at the start of a token. 101 $rcursor = $cursor - (int)$inside_tag; 102 103 // Column number is cheap, so we calculate it every round. 104 // We're interested at the *end* of the newline string, so 105 // we need to add strlen($nl) == 1 to $nl_pos before subtracting it 106 // from our "rcursor" position. 107 $nl_pos = strrpos($html, $nl, $rcursor - $length); 108 $current_col = $rcursor - (is_bool($nl_pos) ? 0 : $nl_pos + 1); 109 110 // recalculate lines 111 if ($synchronize_interval && // synchronization is on 112 $cursor > 0 && // cursor is further than zero 113 $loops % $synchronize_interval === 0) { // time to synchronize! 114 $current_line = 1 + $this->substrCount($html, $nl, 0, $cursor); 115 } 116 } 117 118 $position_next_lt = strpos($html, '<', $cursor); 119 $position_next_gt = strpos($html, '>', $cursor); 120 121 // triggers on "<b>asdf</b>" but not "asdf <b></b>" 122 // special case to set up context 123 if ($position_next_lt === $cursor) { 124 $inside_tag = true; 125 $cursor++; 126 } 127 128 if (!$inside_tag && $position_next_lt !== false) { 129 // We are not inside tag and there still is another tag to parse 130 $token = new 131 HTMLPurifier_Token_Text( 132 $this->parseText( 133 substr( 134 $html, 135 $cursor, 136 $position_next_lt - $cursor 137 ), $config 138 ) 139 ); 140 if ($maintain_line_numbers) { 141 $token->rawPosition($current_line, $current_col); 142 $current_line += $this->substrCount($html, $nl, $cursor, $position_next_lt - $cursor); 143 } 144 $array[] = $token; 145 $cursor = $position_next_lt + 1; 146 $inside_tag = true; 147 continue; 148 } elseif (!$inside_tag) { 149 // We are not inside tag but there are no more tags 150 // If we're already at the end, break 151 if ($cursor === strlen($html)) { 152 break; 153 } 154 // Create Text of rest of string 155 $token = new 156 HTMLPurifier_Token_Text( 157 $this->parseText( 158 substr( 159 $html, 160 $cursor 161 ), $config 162 ) 163 ); 164 if ($maintain_line_numbers) { 165 $token->rawPosition($current_line, $current_col); 166 } 167 $array[] = $token; 168 break; 169 } elseif ($inside_tag && $position_next_gt !== false) { 170 // We are in tag and it is well formed 171 // Grab the internals of the tag 172 $strlen_segment = $position_next_gt - $cursor; 173 174 if ($strlen_segment < 1) { 175 // there's nothing to process! 176 $token = new HTMLPurifier_Token_Text('<'); 177 $cursor++; 178 continue; 179 } 180 181 $segment = substr($html, $cursor, $strlen_segment); 182 183 if ($segment === false) { 184 // somehow, we attempted to access beyond the end of 185 // the string, defense-in-depth, reported by Nate Abele 186 break; 187 } 188 189 // Check if it's a comment 190 if (substr($segment, 0, 3) === '!--') { 191 // re-determine segment length, looking for --> 192 $position_comment_end = strpos($html, '-->', $cursor); 193 if ($position_comment_end === false) { 194 // uh oh, we have a comment that extends to 195 // infinity. Can't be helped: set comment 196 // end position to end of string 197 if ($e) { 198 $e->send(E_WARNING, 'Lexer: Unclosed comment'); 199 } 200 $position_comment_end = strlen($html); 201 $end = true; 202 } else { 203 $end = false; 204 } 205 $strlen_segment = $position_comment_end - $cursor; 206 $segment = substr($html, $cursor, $strlen_segment); 207 $token = new 208 HTMLPurifier_Token_Comment( 209 substr( 210 $segment, 211 3, 212 $strlen_segment - 3 213 ) 214 ); 215 if ($maintain_line_numbers) { 216 $token->rawPosition($current_line, $current_col); 217 $current_line += $this->substrCount($html, $nl, $cursor, $strlen_segment); 218 } 219 $array[] = $token; 220 $cursor = $end ? $position_comment_end : $position_comment_end + 3; 221 $inside_tag = false; 222 continue; 223 } 224 225 // Check if it's an end tag 226 $is_end_tag = (strpos($segment, '/') === 0); 227 if ($is_end_tag) { 228 $type = substr($segment, 1); 229 $token = new HTMLPurifier_Token_End($type); 230 if ($maintain_line_numbers) { 231 $token->rawPosition($current_line, $current_col); 232 $current_line += $this->substrCount($html, $nl, $cursor, $position_next_gt - $cursor); 233 } 234 $array[] = $token; 235 $inside_tag = false; 236 $cursor = $position_next_gt + 1; 237 continue; 238 } 239 240 // Check leading character is alnum, if not, we may 241 // have accidently grabbed an emoticon. Translate into 242 // text and go our merry way 243 if (!ctype_alpha($segment[0])) { 244 // XML: $segment[0] !== '_' && $segment[0] !== ':' 245 if ($e) { 246 $e->send(E_NOTICE, 'Lexer: Unescaped lt'); 247 } 248 $token = new HTMLPurifier_Token_Text('<'); 249 if ($maintain_line_numbers) { 250 $token->rawPosition($current_line, $current_col); 251 $current_line += $this->substrCount($html, $nl, $cursor, $position_next_gt - $cursor); 252 } 253 $array[] = $token; 254 $inside_tag = false; 255 continue; 256 } 257 258 // Check if it is explicitly self closing, if so, remove 259 // trailing slash. Remember, we could have a tag like <br>, so 260 // any later token processing scripts must convert improperly 261 // classified EmptyTags from StartTags. 262 $is_self_closing = (strrpos($segment, '/') === $strlen_segment - 1); 263 if ($is_self_closing) { 264 $strlen_segment--; 265 $segment = substr($segment, 0, $strlen_segment); 266 } 267 268 // Check if there are any attributes 269 $position_first_space = strcspn($segment, $this->_whitespace); 270 271 if ($position_first_space >= $strlen_segment) { 272 if ($is_self_closing) { 273 $token = new HTMLPurifier_Token_Empty($segment); 274 } else { 275 $token = new HTMLPurifier_Token_Start($segment); 276 } 277 if ($maintain_line_numbers) { 278 $token->rawPosition($current_line, $current_col); 279 $current_line += $this->substrCount($html, $nl, $cursor, $position_next_gt - $cursor); 280 } 281 $array[] = $token; 282 $inside_tag = false; 283 $cursor = $position_next_gt + 1; 284 continue; 285 } 286 287 // Grab out all the data 288 $type = substr($segment, 0, $position_first_space); 289 $attribute_string = 290 trim( 291 substr( 292 $segment, 293 $position_first_space 294 ) 295 ); 296 if ($attribute_string) { 297 $attr = $this->parseAttributeString( 298 $attribute_string, 299 $config, 300 $context 301 ); 302 } else { 303 $attr = array(); 304 } 305 306 if ($is_self_closing) { 307 $token = new HTMLPurifier_Token_Empty($type, $attr); 308 } else { 309 $token = new HTMLPurifier_Token_Start($type, $attr); 310 } 311 if ($maintain_line_numbers) { 312 $token->rawPosition($current_line, $current_col); 313 $current_line += $this->substrCount($html, $nl, $cursor, $position_next_gt - $cursor); 314 } 315 $array[] = $token; 316 $cursor = $position_next_gt + 1; 317 $inside_tag = false; 318 continue; 319 } else { 320 // inside tag, but there's no ending > sign 321 if ($e) { 322 $e->send(E_WARNING, 'Lexer: Missing gt'); 323 } 324 $token = new 325 HTMLPurifier_Token_Text( 326 '<' . 327 $this->parseText( 328 substr($html, $cursor), $config 329 ) 330 ); 331 if ($maintain_line_numbers) { 332 $token->rawPosition($current_line, $current_col); 333 } 334 // no cursor scroll? Hmm... 335 $array[] = $token; 336 break; 337 } 338 break; 339 } 340 341 $context->destroy('CurrentLine'); 342 $context->destroy('CurrentCol'); 343 return $array; 344 } 345 346 /** 347 * PHP 5.0.x compatible substr_count that implements offset and length 348 * @param string $haystack 349 * @param string $needle 350 * @param int $offset 351 * @param int $length 352 * @return int 353 */ 354 protected function substrCount($haystack, $needle, $offset, $length) 355 { 356 static $oldVersion; 357 if ($oldVersion === null) { 358 $oldVersion = version_compare(PHP_VERSION, '5.1', '<'); 359 } 360 if ($oldVersion) { 361 $haystack = substr($haystack, $offset, $length); 362 return substr_count($haystack, $needle); 363 } else { 364 return substr_count($haystack, $needle, $offset, $length); 365 } 366 } 367 368 /** 369 * Takes the inside of an HTML tag and makes an assoc array of attributes. 370 * 371 * @param string $string Inside of tag excluding name. 372 * @param HTMLPurifier_Config $config 373 * @param HTMLPurifier_Context $context 374 * @return array Assoc array of attributes. 375 */ 376 public function parseAttributeString($string, $config, $context) 377 { 378 $string = (string)$string; // quick typecast 379 380 if ($string == '') { 381 return array(); 382 } // no attributes 383 384 $e = false; 385 if ($config->get('Core.CollectErrors')) { 386 $e =& $context->get('ErrorCollector'); 387 } 388 389 // let's see if we can abort as quickly as possible 390 // one equal sign, no spaces => one attribute 391 $num_equal = substr_count($string, '='); 392 $has_space = strpos($string, ' '); 393 if ($num_equal === 0 && !$has_space) { 394 // bool attribute 395 return array($string => $string); 396 } elseif ($num_equal === 1 && !$has_space) { 397 // only one attribute 398 list($key, $quoted_value) = explode('=', $string); 399 $quoted_value = trim($quoted_value); 400 if (!$key) { 401 if ($e) { 402 $e->send(E_ERROR, 'Lexer: Missing attribute key'); 403 } 404 return array(); 405 } 406 if (!$quoted_value) { 407 return array($key => ''); 408 } 409 $first_char = @$quoted_value[0]; 410 $last_char = @$quoted_value[strlen($quoted_value) - 1]; 411 412 $same_quote = ($first_char == $last_char); 413 $open_quote = ($first_char == '"' || $first_char == "'"); 414 415 if ($same_quote && $open_quote) { 416 // well behaved 417 $value = substr($quoted_value, 1, strlen($quoted_value) - 2); 418 } else { 419 // not well behaved 420 if ($open_quote) { 421 if ($e) { 422 $e->send(E_ERROR, 'Lexer: Missing end quote'); 423 } 424 $value = substr($quoted_value, 1); 425 } else { 426 $value = $quoted_value; 427 } 428 } 429 if ($value === false) { 430 $value = ''; 431 } 432 return array($key => $this->parseAttr($value, $config)); 433 } 434 435 // setup loop environment 436 $array = array(); // return assoc array of attributes 437 $cursor = 0; // current position in string (moves forward) 438 $size = strlen($string); // size of the string (stays the same) 439 440 // if we have unquoted attributes, the parser expects a terminating 441 // space, so let's guarantee that there's always a terminating space. 442 $string .= ' '; 443 444 $old_cursor = -1; 445 while ($cursor < $size) { 446 if ($old_cursor >= $cursor) { 447 throw new Exception("Infinite loop detected"); 448 } 449 $old_cursor = $cursor; 450 451 $cursor += ($value = strspn($string, $this->_whitespace, $cursor)); 452 // grab the key 453 454 $key_begin = $cursor; //we're currently at the start of the key 455 456 // scroll past all characters that are the key (not whitespace or =) 457 $cursor += strcspn($string, $this->_whitespace . '=', $cursor); 458 459 $key_end = $cursor; // now at the end of the key 460 461 $key = substr($string, $key_begin, $key_end - $key_begin); 462 463 if (!$key) { 464 if ($e) { 465 $e->send(E_ERROR, 'Lexer: Missing attribute key'); 466 } 467 $cursor += 1 + strcspn($string, $this->_whitespace, $cursor + 1); // prevent infinite loop 468 continue; // empty key 469 } 470 471 // scroll past all whitespace 472 $cursor += strspn($string, $this->_whitespace, $cursor); 473 474 if ($cursor >= $size) { 475 $array[$key] = $key; 476 break; 477 } 478 479 // if the next character is an equal sign, we've got a regular 480 // pair, otherwise, it's a bool attribute 481 $first_char = @$string[$cursor]; 482 483 if ($first_char == '=') { 484 // key="value" 485 486 $cursor++; 487 $cursor += strspn($string, $this->_whitespace, $cursor); 488 489 if ($cursor === false) { 490 $array[$key] = ''; 491 break; 492 } 493 494 // we might be in front of a quote right now 495 496 $char = @$string[$cursor]; 497 498 if ($char == '"' || $char == "'") { 499 // it's quoted, end bound is $char 500 $cursor++; 501 $value_begin = $cursor; 502 $cursor = strpos($string, $char, $cursor); 503 $value_end = $cursor; 504 } else { 505 // it's not quoted, end bound is whitespace 506 $value_begin = $cursor; 507 $cursor += strcspn($string, $this->_whitespace, $cursor); 508 $value_end = $cursor; 509 } 510 511 // we reached a premature end 512 if ($cursor === false) { 513 $cursor = $size; 514 $value_end = $cursor; 515 } 516 517 $value = substr($string, $value_begin, $value_end - $value_begin); 518 if ($value === false) { 519 $value = ''; 520 } 521 $array[$key] = $this->parseAttr($value, $config); 522 $cursor++; 523 } else { 524 // boolattr 525 if ($key !== '') { 526 $array[$key] = $key; 527 } else { 528 // purely theoretical 529 if ($e) { 530 $e->send(E_ERROR, 'Lexer: Missing attribute key'); 531 } 532 } 533 } 534 } 535 return $array; 536 } 537 } 538 539 // vim: et sw=4 sts=4
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