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https://github.com/ezyang/htmlpurifier.git
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a3d71fe606
There are some deep DOMs you can hit the maximum nesting level limit in tokenizeDOM (we've experienced this even with maximum nesting level of 300). Here is an iterative version of the same function with simple queue/dequeue approach. Signed-off-by: Maxim Krizhanovsky <darhazer@gmail.com>
244 lines
9.3 KiB
PHP
244 lines
9.3 KiB
PHP
<?php
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/**
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* Parser that uses PHP 5's DOM extension (part of the core).
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*
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* In PHP 5, the DOM XML extension was revamped into DOM and added to the core.
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* It gives us a forgiving HTML parser, which we use to transform the HTML
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* into a DOM, and then into the tokens. It is blazingly fast (for large
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* documents, it performs twenty times faster than
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* HTMLPurifier_Lexer_DirectLex,and is the default choice for PHP 5.
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*
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* @note Any empty elements will have empty tokens associated with them, even if
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* this is prohibited by the spec. This is cannot be fixed until the spec
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* comes into play.
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*
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* @note PHP's DOM extension does not actually parse any entities, we use
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* our own function to do that.
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*
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* @warning DOM tends to drop whitespace, which may wreak havoc on indenting.
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* If this is a huge problem, due to the fact that HTML is hand
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* edited and you are unable to get a parser cache that caches the
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* the output of HTML Purifier while keeping the original HTML lying
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* around, you may want to run Tidy on the resulting output or use
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* HTMLPurifier_DirectLex
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*/
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class HTMLPurifier_Lexer_DOMLex extends HTMLPurifier_Lexer
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{
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private $factory;
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public function __construct() {
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// setup the factory
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parent::__construct();
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$this->factory = new HTMLPurifier_TokenFactory();
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}
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public function tokenizeHTML($html, $config, $context) {
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$html = $this->normalize($html, $config, $context);
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// attempt to armor stray angled brackets that cannot possibly
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// form tags and thus are probably being used as emoticons
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if ($config->get('Core.AggressivelyFixLt')) {
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$char = '[^a-z!\/]';
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$comment = "/<!--(.*?)(-->|\z)/is";
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$html = preg_replace_callback($comment, array($this, 'callbackArmorCommentEntities'), $html);
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do {
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$old = $html;
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$html = preg_replace("/<($char)/i", '<\\1', $html);
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} while ($html !== $old);
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$html = preg_replace_callback($comment, array($this, 'callbackUndoCommentSubst'), $html); // fix comments
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}
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// preprocess html, essential for UTF-8
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$html = $this->wrapHTML($html, $config, $context);
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$doc = new DOMDocument();
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$doc->encoding = 'UTF-8'; // theoretically, the above has this covered
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set_error_handler(array($this, 'muteErrorHandler'));
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$doc->loadHTML($html);
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restore_error_handler();
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$tokens = array();
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$this->tokenizeDOM(
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$doc->getElementsByTagName('html')->item(0)-> // <html>
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getElementsByTagName('body')->item(0)-> // <body>
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getElementsByTagName('div')->item(0) // <div>
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, $tokens);
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return $tokens;
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}
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/**
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* Iterative function that tokenizes a node, putting it into an accumulator.
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* To iterate is human, to recurse divine - L. Peter Deutsch
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* @param $node DOMNode to be tokenized.
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* @param $tokens Array-list of already tokenized tokens.
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* @returns Tokens of node appended to previously passed tokens.
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*/
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protected function tokenizeDOM($node, &$tokens) {
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$level = 0;
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$nodes = array($level => array($node));
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$closingNodes = array();
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do {
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while (!empty($nodes[$level])) {
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$node = array_shift($nodes[$level]); // FIFO
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$collect = $level > 0 ? true : false;
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$needEndingTag = $this->createStartNode($node, $tokens, $collect);
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if ($needEndingTag) {
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$closingNodes[$level][] = $node;
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}
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if ($node->childNodes && $node->childNodes->length) {
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$level++;
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$nodes[$level] = array();
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foreach ($node->childNodes as $childNode) {
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array_push($nodes[$level], $childNode);
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}
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}
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}
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$level--;
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if ($level && isset($closingNodes[$level])) {
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while($node = array_pop($closingNodes[$level])) {
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$this->createEndNode($node, $tokens);
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}
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}
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} while ($level > 0);
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}
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/**
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* @param $node DOMNode to be tokenized.
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* @param $tokens Array-list of already tokenized tokens.
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* @param $collect Says whether or start and close are collected, set to
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* false at first recursion because it's the implicit DIV
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* tag you're dealing with.
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* @returns bool if the token needs an endtoken
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*/
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protected function createStartNode($node, &$tokens, $collect) {
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// intercept non element nodes. WE MUST catch all of them,
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// but we're not getting the character reference nodes because
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// those should have been preprocessed
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if ($node->nodeType === XML_TEXT_NODE) {
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$tokens[] = $this->factory->createText($node->data);
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return false;
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} elseif ($node->nodeType === XML_CDATA_SECTION_NODE) {
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// undo libxml's special treatment of <script> and <style> tags
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$last = end($tokens);
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$data = $node->data;
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// (note $node->tagname is already normalized)
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if ($last instanceof HTMLPurifier_Token_Start && ($last->name == 'script' || $last->name == 'style')) {
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$new_data = trim($data);
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if (substr($new_data, 0, 4) === '<!--') {
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$data = substr($new_data, 4);
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if (substr($data, -3) === '-->') {
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$data = substr($data, 0, -3);
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} else {
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// Highly suspicious! Not sure what to do...
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}
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}
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}
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$tokens[] = $this->factory->createText($this->parseData($data));
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return false;
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} elseif ($node->nodeType === XML_COMMENT_NODE) {
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// this is code is only invoked for comments in script/style in versions
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// of libxml pre-2.6.28 (regular comments, of course, are still
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// handled regularly)
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$tokens[] = $this->factory->createComment($node->data);
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return false;
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} elseif (
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// not-well tested: there may be other nodes we have to grab
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$node->nodeType !== XML_ELEMENT_NODE
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) {
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return false;
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}
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$attr = $node->hasAttributes() ? $this->transformAttrToAssoc($node->attributes) : array();
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// We still have to make sure that the element actually IS empty
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if (!$node->childNodes->length) {
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if ($collect) {
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$tokens[] = $this->factory->createEmpty($node->tagName, $attr);
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}
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return false;
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} else {
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if ($collect) {
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$tokens[] = $this->factory->createStart(
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$tag_name = $node->tagName, // somehow, it get's dropped
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$attr
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);
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}
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return true;
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}
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}
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protected function createEndNode($node, &$tokens) {
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$tokens[] = $this->factory->createEnd($node->tagName);
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}
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/**
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* Converts a DOMNamedNodeMap of DOMAttr objects into an assoc array.
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*
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* @param $attribute_list DOMNamedNodeMap of DOMAttr objects.
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* @returns Associative array of attributes.
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*/
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protected function transformAttrToAssoc($node_map) {
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// NamedNodeMap is documented very well, so we're using undocumented
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// features, namely, the fact that it implements Iterator and
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// has a ->length attribute
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if ($node_map->length === 0) return array();
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$array = array();
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foreach ($node_map as $attr) {
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$array[$attr->name] = $attr->value;
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}
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return $array;
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}
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/**
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* An error handler that mutes all errors
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*/
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public function muteErrorHandler($errno, $errstr) {}
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/**
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* Callback function for undoing escaping of stray angled brackets
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* in comments
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*/
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public function callbackUndoCommentSubst($matches) {
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return '<!--' . strtr($matches[1], array('&'=>'&','<'=>'<')) . $matches[2];
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}
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/**
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* Callback function that entity-izes ampersands in comments so that
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* callbackUndoCommentSubst doesn't clobber them
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*/
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public function callbackArmorCommentEntities($matches) {
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return '<!--' . str_replace('&', '&', $matches[1]) . $matches[2];
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}
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/**
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* Wraps an HTML fragment in the necessary HTML
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*/
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protected function wrapHTML($html, $config, $context) {
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$def = $config->getDefinition('HTML');
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$ret = '';
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if (!empty($def->doctype->dtdPublic) || !empty($def->doctype->dtdSystem)) {
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$ret .= '<!DOCTYPE html ';
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if (!empty($def->doctype->dtdPublic)) $ret .= 'PUBLIC "' . $def->doctype->dtdPublic . '" ';
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if (!empty($def->doctype->dtdSystem)) $ret .= '"' . $def->doctype->dtdSystem . '" ';
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$ret .= '>';
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}
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$ret .= '<html><head>';
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$ret .= '<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />';
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// No protection if $html contains a stray </div>!
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$ret .= '</head><body><div>'.$html.'</div></body></html>';
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return $ret;
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}
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}
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// vim: et sw=4 sts=4
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