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Diffstat (limited to 'library/HTMLPurifier/Lexer/DOMLex.php')
| -rw-r--r-- | library/HTMLPurifier/Lexer/DOMLex.php | 213 |
1 files changed, 213 insertions, 0 deletions
diff --git a/library/HTMLPurifier/Lexer/DOMLex.php b/library/HTMLPurifier/Lexer/DOMLex.php new file mode 100644 index 000000000..20dc2ed48 --- /dev/null +++ b/library/HTMLPurifier/Lexer/DOMLex.php @@ -0,0 +1,213 @@ +<?php + +/** + * Parser that uses PHP 5's DOM extension (part of the core). + * + * In PHP 5, the DOM XML extension was revamped into DOM and added to the core. + * It gives us a forgiving HTML parser, which we use to transform the HTML + * into a DOM, and then into the tokens. It is blazingly fast (for large + * documents, it performs twenty times faster than + * HTMLPurifier_Lexer_DirectLex,and is the default choice for PHP 5. + * + * @note Any empty elements will have empty tokens associated with them, even if + * this is prohibited by the spec. This is cannot be fixed until the spec + * comes into play. + * + * @note PHP's DOM extension does not actually parse any entities, we use + * our own function to do that. + * + * @warning DOM tends to drop whitespace, which may wreak havoc on indenting. + * If this is a huge problem, due to the fact that HTML is hand + * edited and you are unable to get a parser cache that caches the + * the output of HTML Purifier while keeping the original HTML lying + * around, you may want to run Tidy on the resulting output or use + * HTMLPurifier_DirectLex + */ + +class HTMLPurifier_Lexer_DOMLex extends HTMLPurifier_Lexer +{ + + private $factory; + + public function __construct() { + // setup the factory + parent::__construct(); + $this->factory = new HTMLPurifier_TokenFactory(); + } + + public function tokenizeHTML($html, $config, $context) { + + $html = $this->normalize($html, $config, $context); + + // attempt to armor stray angled brackets that cannot possibly + // form tags and thus are probably being used as emoticons + if ($config->get('Core.AggressivelyFixLt')) { + $char = '[^a-z!\/]'; + $comment = "/<!--(.*?)(-->|\z)/is"; + $html = preg_replace_callback($comment, array($this, 'callbackArmorCommentEntities'), $html); + do { + $old = $html; + $html = preg_replace("/<($char)/i", '<\\1', $html); + } while ($html !== $old); + $html = preg_replace_callback($comment, array($this, 'callbackUndoCommentSubst'), $html); // fix comments + } + + // preprocess html, essential for UTF-8 + $html = $this->wrapHTML($html, $config, $context); + + $doc = new DOMDocument(); + $doc->encoding = 'UTF-8'; // theoretically, the above has this covered + + set_error_handler(array($this, 'muteErrorHandler')); + $doc->loadHTML($html); + restore_error_handler(); + + $tokens = array(); + $this->tokenizeDOM( + $doc->getElementsByTagName('html')->item(0)-> // <html> + getElementsByTagName('body')->item(0)-> // <body> + getElementsByTagName('div')->item(0) // <div> + , $tokens); + return $tokens; + } + + /** + * Recursive function that tokenizes a node, putting it into an accumulator. + * + * @param $node DOMNode to be tokenized. + * @param $tokens Array-list of already tokenized tokens. + * @param $collect Says whether or start and close are collected, set to + * false at first recursion because it's the implicit DIV + * tag you're dealing with. + * @returns Tokens of node appended to previously passed tokens. + */ + protected function tokenizeDOM($node, &$tokens, $collect = false) { + + // intercept non element nodes. WE MUST catch all of them, + // but we're not getting the character reference nodes because + // those should have been preprocessed + if ($node->nodeType === XML_TEXT_NODE) { + $tokens[] = $this->factory->createText($node->data); + return; + } elseif ($node->nodeType === XML_CDATA_SECTION_NODE) { + // undo libxml's special treatment of <script> and <style> tags + $last = end($tokens); + $data = $node->data; + // (note $node->tagname is already normalized) + if ($last instanceof HTMLPurifier_Token_Start && ($last->name == 'script' || $last->name == 'style')) { + $new_data = trim($data); + if (substr($new_data, 0, 4) === '<!--') { + $data = substr($new_data, 4); + if (substr($data, -3) === '-->') { + $data = substr($data, 0, -3); + } else { + // Highly suspicious! Not sure what to do... + } + } + } + $tokens[] = $this->factory->createText($this->parseData($data)); + return; + } elseif ($node->nodeType === XML_COMMENT_NODE) { + // this is code is only invoked for comments in script/style in versions + // of libxml pre-2.6.28 (regular comments, of course, are still + // handled regularly) + $tokens[] = $this->factory->createComment($node->data); + return; + } elseif ( + // not-well tested: there may be other nodes we have to grab + $node->nodeType !== XML_ELEMENT_NODE + ) { + return; + } + + $attr = $node->hasAttributes() ? + $this->transformAttrToAssoc($node->attributes) : + array(); + + // We still have to make sure that the element actually IS empty + if (!$node->childNodes->length) { + if ($collect) { + $tokens[] = $this->factory->createEmpty($node->tagName, $attr); + } + } else { + if ($collect) { // don't wrap on first iteration + $tokens[] = $this->factory->createStart( + $tag_name = $node->tagName, // somehow, it get's dropped + $attr + ); + } + foreach ($node->childNodes as $node) { + // remember, it's an accumulator. Otherwise, we'd have + // to use array_merge + $this->tokenizeDOM($node, $tokens, true); + } + if ($collect) { + $tokens[] = $this->factory->createEnd($tag_name); + } + } + + } + + /** + * Converts a DOMNamedNodeMap of DOMAttr objects into an assoc array. + * + * @param $attribute_list DOMNamedNodeMap of DOMAttr objects. + * @returns Associative array of attributes. + */ + protected function transformAttrToAssoc($node_map) { + // NamedNodeMap is documented very well, so we're using undocumented + // features, namely, the fact that it implements Iterator and + // has a ->length attribute + if ($node_map->length === 0) return array(); + $array = array(); + foreach ($node_map as $attr) { + $array[$attr->name] = $attr->value; + } + return $array; + } + + /** + * An error handler that mutes all errors + */ + public function muteErrorHandler($errno, $errstr) {} + + /** + * Callback function for undoing escaping of stray angled brackets + * in comments + */ + public function callbackUndoCommentSubst($matches) { + return '<!--' . strtr($matches[1], array('&'=>'&','<'=>'<')) . $matches[2]; + } + + /** + * Callback function that entity-izes ampersands in comments so that + * callbackUndoCommentSubst doesn't clobber them + */ + public function callbackArmorCommentEntities($matches) { + return '<!--' . str_replace('&', '&', $matches[1]) . $matches[2]; + } + + /** + * Wraps an HTML fragment in the necessary HTML + */ + protected function wrapHTML($html, $config, $context) { + $def = $config->getDefinition('HTML'); + $ret = ''; + + if (!empty($def->doctype->dtdPublic) || !empty($def->doctype->dtdSystem)) { + $ret .= '<!DOCTYPE html '; + if (!empty($def->doctype->dtdPublic)) $ret .= 'PUBLIC "' . $def->doctype->dtdPublic . '" '; + if (!empty($def->doctype->dtdSystem)) $ret .= '"' . $def->doctype->dtdSystem . '" '; + $ret .= '>'; + } + + $ret .= '<html><head>'; + $ret .= '<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />'; + // No protection if $html contains a stray </div>! + $ret .= '</head><body><div>'.$html.'</div></body></html>'; + return $ret; + } + +} + +// vim: et sw=4 sts=4 |