<?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", '<\\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('&' => '&', '<' => '<')) . $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('&', '&', $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
