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1 <?php 2 3 /** 4 * Parser that uses PHP 5's DOM extension (part of the core). 5 * 6 * In PHP 5, the DOM XML extension was revamped into DOM and added to the core. 7 * It gives us a forgiving HTML parser, which we use to transform the HTML 8 * into a DOM, and then into the tokens. It is blazingly fast (for large 9 * documents, it performs twenty times faster than 10 * HTMLPurifier_Lexer_DirectLex,and is the default choice for PHP 5. 11 * 12 * @note Any empty elements will have empty tokens associated with them, even if 13 * this is prohibited by the spec. This is cannot be fixed until the spec 14 * comes into play. 15 * 16 * @note PHP's DOM extension does not actually parse any entities, we use 17 * our own function to do that. 18 * 19 * @warning DOM tends to drop whitespace, which may wreak havoc on indenting. 20 * If this is a huge problem, due to the fact that HTML is hand 21 * edited and you are unable to get a parser cache that caches the 22 * the output of HTML Purifier while keeping the original HTML lying 23 * around, you may want to run Tidy on the resulting output or use 24 * HTMLPurifier_DirectLex 25 */ 26 27 class HTMLPurifier_Lexer_DOMLex extends HTMLPurifier_Lexer 28 { 29 30 /** 31 * @type HTMLPurifier_TokenFactory 32 */ 33 private $factory; 34 35 public function __construct() 36 { 37 // setup the factory 38 parent::__construct(); 39 $this->factory = new HTMLPurifier_TokenFactory(); 40 } 41 42 /** 43 * @param string $html 44 * @param HTMLPurifier_Config $config 45 * @param HTMLPurifier_Context $context 46 * @return HTMLPurifier_Token[] 47 */ 48 public function tokenizeHTML($html, $config, $context) 49 { 50 $html = $this->normalize($html, $config, $context); 51 52 // attempt to armor stray angled brackets that cannot possibly 53 // form tags and thus are probably being used as emoticons 54 if ($config->get('Core.AggressivelyFixLt')) { 55 $char = '[^a-z!\/]'; 56 $comment = "/<!--(.*?)(-->|\z)/is"; 57 $html = preg_replace_callback($comment, array($this, 'callbackArmorCommentEntities'), $html); 58 do { 59 $old = $html; 60 $html = preg_replace("/<($char)/i", '<\\1', $html); 61 } while ($html !== $old); 62 $html = preg_replace_callback($comment, array($this, 'callbackUndoCommentSubst'), $html); // fix comments 63 } 64 65 // preprocess html, essential for UTF-8 66 $html = $this->wrapHTML($html, $config, $context); 67 68 $doc = new DOMDocument(); 69 $doc->encoding = 'UTF-8'; // theoretically, the above has this covered 70 71 set_error_handler(array($this, 'muteErrorHandler')); 72 $doc->loadHTML($html); 73 restore_error_handler(); 74 75 $tokens = array(); 76 $this->tokenizeDOM( 77 $doc->getElementsByTagName('html')->item(0)-> // <html> 78 getElementsByTagName('body')->item(0)-> // <body> 79 getElementsByTagName('div')->item(0), // <div> 80 $tokens 81 ); 82 return $tokens; 83 } 84 85 /** 86 * Iterative function that tokenizes a node, putting it into an accumulator. 87 * To iterate is human, to recurse divine - L. Peter Deutsch 88 * @param DOMNode $node DOMNode to be tokenized. 89 * @param HTMLPurifier_Token[] $tokens Array-list of already tokenized tokens. 90 * @return HTMLPurifier_Token of node appended to previously passed tokens. 91 */ 92 protected function tokenizeDOM($node, &$tokens) 93 { 94 $level = 0; 95 $nodes = array($level => new HTMLPurifier_Queue(array($node))); 96 $closingNodes = array(); 97 do { 98 while (!$nodes[$level]->isEmpty()) { 99 $node = $nodes[$level]->shift(); // FIFO 100 $collect = $level > 0 ? true : false; 101 $needEndingTag = $this->createStartNode($node, $tokens, $collect); 102 if ($needEndingTag) { 103 $closingNodes[$level][] = $node; 104 } 105 if ($node->childNodes && $node->childNodes->length) { 106 $level++; 107 $nodes[$level] = new HTMLPurifier_Queue(); 108 foreach ($node->childNodes as $childNode) { 109 $nodes[$level]->push($childNode); 110 } 111 } 112 } 113 $level--; 114 if ($level && isset($closingNodes[$level])) { 115 while ($node = array_pop($closingNodes[$level])) { 116 $this->createEndNode($node, $tokens); 117 } 118 } 119 } while ($level > 0); 120 } 121 122 /** 123 * @param DOMNode $node DOMNode to be tokenized. 124 * @param HTMLPurifier_Token[] $tokens Array-list of already tokenized tokens. 125 * @param bool $collect Says whether or start and close are collected, set to 126 * false at first recursion because it's the implicit DIV 127 * tag you're dealing with. 128 * @return bool if the token needs an endtoken 129 * @todo data and tagName properties don't seem to exist in DOMNode? 130 */ 131 protected function createStartNode($node, &$tokens, $collect) 132 { 133 // intercept non element nodes. WE MUST catch all of them, 134 // but we're not getting the character reference nodes because 135 // those should have been preprocessed 136 if ($node->nodeType === XML_TEXT_NODE) { 137 $tokens[] = $this->factory->createText($node->data); 138 return false; 139 } elseif ($node->nodeType === XML_CDATA_SECTION_NODE) { 140 // undo libxml's special treatment of <script> and <style> tags 141 $last = end($tokens); 142 $data = $node->data; 143 // (note $node->tagname is already normalized) 144 if ($last instanceof HTMLPurifier_Token_Start && ($last->name == 'script' || $last->name == 'style')) { 145 $new_data = trim($data); 146 if (substr($new_data, 0, 4) === '<!--') { 147 $data = substr($new_data, 4); 148 if (substr($data, -3) === '-->') { 149 $data = substr($data, 0, -3); 150 } else { 151 // Highly suspicious! Not sure what to do... 152 } 153 } 154 } 155 $tokens[] = $this->factory->createText($this->parseData($data)); 156 return false; 157 } elseif ($node->nodeType === XML_COMMENT_NODE) { 158 // this is code is only invoked for comments in script/style in versions 159 // of libxml pre-2.6.28 (regular comments, of course, are still 160 // handled regularly) 161 $tokens[] = $this->factory->createComment($node->data); 162 return false; 163 } elseif ($node->nodeType !== XML_ELEMENT_NODE) { 164 // not-well tested: there may be other nodes we have to grab 165 return false; 166 } 167 168 $attr = $node->hasAttributes() ? $this->transformAttrToAssoc($node->attributes) : array(); 169 170 // We still have to make sure that the element actually IS empty 171 if (!$node->childNodes->length) { 172 if ($collect) { 173 $tokens[] = $this->factory->createEmpty($node->tagName, $attr); 174 } 175 return false; 176 } else { 177 if ($collect) { 178 $tokens[] = $this->factory->createStart( 179 $tag_name = $node->tagName, // somehow, it get's dropped 180 $attr 181 ); 182 } 183 return true; 184 } 185 } 186 187 /** 188 * @param DOMNode $node 189 * @param HTMLPurifier_Token[] $tokens 190 */ 191 protected function createEndNode($node, &$tokens) 192 { 193 $tokens[] = $this->factory->createEnd($node->tagName); 194 } 195 196 197 /** 198 * Converts a DOMNamedNodeMap of DOMAttr objects into an assoc array. 199 * 200 * @param DOMNamedNodeMap $node_map DOMNamedNodeMap of DOMAttr objects. 201 * @return array Associative array of attributes. 202 */ 203 protected function transformAttrToAssoc($node_map) 204 { 205 // NamedNodeMap is documented very well, so we're using undocumented 206 // features, namely, the fact that it implements Iterator and 207 // has a ->length attribute 208 if ($node_map->length === 0) { 209 return array(); 210 } 211 $array = array(); 212 foreach ($node_map as $attr) { 213 $array[$attr->name] = $attr->value; 214 } 215 return $array; 216 } 217 218 /** 219 * An error handler that mutes all errors 220 * @param int $errno 221 * @param string $errstr 222 */ 223 public function muteErrorHandler($errno, $errstr) 224 { 225 } 226 227 /** 228 * Callback function for undoing escaping of stray angled brackets 229 * in comments 230 * @param array $matches 231 * @return string 232 */ 233 public function callbackUndoCommentSubst($matches) 234 { 235 return '<!--' . strtr($matches[1], array('&' => '&', '<' => '<')) . $matches[2]; 236 } 237 238 /** 239 * Callback function that entity-izes ampersands in comments so that 240 * callbackUndoCommentSubst doesn't clobber them 241 * @param array $matches 242 * @return string 243 */ 244 public function callbackArmorCommentEntities($matches) 245 { 246 return '<!--' . str_replace('&', '&', $matches[1]) . $matches[2]; 247 } 248 249 /** 250 * Wraps an HTML fragment in the necessary HTML 251 * @param string $html 252 * @param HTMLPurifier_Config $config 253 * @param HTMLPurifier_Context $context 254 * @return string 255 */ 256 protected function wrapHTML($html, $config, $context) 257 { 258 $def = $config->getDefinition('HTML'); 259 $ret = ''; 260 261 if (!empty($def->doctype->dtdPublic) || !empty($def->doctype->dtdSystem)) { 262 $ret .= '<!DOCTYPE html '; 263 if (!empty($def->doctype->dtdPublic)) { 264 $ret .= 'PUBLIC "' . $def->doctype->dtdPublic . '" '; 265 } 266 if (!empty($def->doctype->dtdSystem)) { 267 $ret .= '"' . $def->doctype->dtdSystem . '" '; 268 } 269 $ret .= '>'; 270 } 271 272 $ret .= '<html><head>'; 273 $ret .= '<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />'; 274 // No protection if $html contains a stray </div>! 275 $ret .= '</head><body><div>' . $html . '</div></body></html>'; 276 return $ret; 277 } 278 } 279 280 // vim: et sw=4 sts=4
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Generated: Tue Mar 17 22:47:18 2015 | Cross-referenced by PHPXref 0.7.1 |