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<?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

{

/**

* @type HTMLPurifier_TokenFactory

private $factory;

public function __construct()

{

// setup the factory

parent::__construct();

$this->factory = new HTMLPurifier_TokenFactory();

}

/**

* @param string $html

* @param HTMLPurifier_Config $config

* @param HTMLPurifier_Context $context

* @return HTMLPurifier_Token[]

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", '&lt;\\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;

}

/**

* Iterative function that tokenizes a node, putting it into an accumulator.

* To iterate is human, to recurse divine - L. Peter Deutsch

* @param DOMNode $node DOMNode to be tokenized.

* @param HTMLPurifier_Token[] $tokens   Array-list of already tokenized tokens.

* @return HTMLPurifier_Token of node appended to previously passed tokens.

protected function tokenizeDOM($node, &$tokens)

{

$level = 0;

$nodes = array($level => new HTMLPurifier_Queue(array($node)));

$closingNodes = array();

do {

while (!$nodes[$level]->isEmpty()) {

$node = $nodes[$level]->shift(); // FIFO

$collect = $level > 0 ? true : false;

$needEndingTag = $this->createStartNode($node, $tokens, $collect);

if ($needEndingTag) {

$closingNodes[$level][] = $node;

}

if ($node->childNodes && $node->childNodes->length) {

$level++;

$nodes[$level] = new HTMLPurifier_Queue();

foreach ($node->childNodes as $childNode) {

$nodes[$level]->push($childNode);

}

$level--;

if ($level && isset($closingNodes[$level])) {

while ($node = array_pop($closingNodes[$level])) {

$this->createEndNode($node, $tokens);

}

} while ($level > 0);

}

/**

* @param DOMNode $node DOMNode to be tokenized.

* @param HTMLPurifier_Token[] $tokens   Array-list of already tokenized tokens.

* @param bool $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.

* @return bool if the token needs an endtoken

* @todo data and tagName properties don't seem to exist in DOMNode?

protected function createStartNode($node, &$tokens, $collect)

{

// 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 false;

} 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 false;

} 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 false;

} elseif ($node->nodeType !== XML_ELEMENT_NODE) {

// not-well tested: there may be other nodes we have to grab

return false;

}

$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);

}

return false;

} else {

if ($collect) {

$tokens[] = $this->factory->createStart(

$tag_name = $node->tagName, // somehow, it get's dropped

$attr

);

}

return true;

}

/**

* @param DOMNode $node

* @param HTMLPurifier_Token[] $tokens

protected function createEndNode($node, &$tokens)

{

$tokens[] = $this->factory->createEnd($node->tagName);

}

/**

* Converts a DOMNamedNodeMap of DOMAttr objects into an assoc array.

* @param DOMNamedNodeMap $node_map DOMNamedNodeMap of DOMAttr objects.

* @return array 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

* @param int $errno

* @param string $errstr

public function muteErrorHandler($errno, $errstr)

{

}

/**

* Callback function for undoing escaping of stray angled brackets

* in comments

* @param array $matches

* @return string

public function callbackUndoCommentSubst($matches)

{

return '<!--' . strtr($matches[1], array('&amp;' => '&', '&lt;' => '<')) . $matches[2];

}

/**

* Callback function that entity-izes ampersands in comments so that

* callbackUndoCommentSubst doesn't clobber them

* @param array $matches

* @return string

public function callbackArmorCommentEntities($matches)

{

return '<!--' . str_replace('&', '&amp;', $matches[1]) . $matches[2];

}

/**

* Wraps an HTML fragment in the necessary HTML

* @param string $html

* @param HTMLPurifier_Config $config

* @param HTMLPurifier_Context $context

* @return string

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

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