mirror of
https://github.com/ezyang/htmlpurifier.git
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9a35dfa6b9
git-svn-id: http://htmlpurifier.org/svnroot/htmlpurifier/trunk@258 48356398-32a2-884e-a903-53898d9a118a
255 lines
8.5 KiB
PHP
255 lines
8.5 KiB
PHP
<?php
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require_once 'HTMLPurifier/Token.php';
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HTMLPurifier_ConfigDef::define(
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'Core', 'AcceptFullDocuments', true,
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'This parameter determines whether or not the filter should accept full '.
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'HTML documents, not just HTML fragments. When on, it will '.
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'drop all sections except the content between body. Depending on '.
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'the implementation in use, this may speed up document parse times.'
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);
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/**
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* Forgivingly lexes HTML (SGML-style) markup into tokens.
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*
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* A lexer parses a string of SGML-style markup and converts them into
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* corresponding tokens. It doesn't check for well-formedness, although its
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* internal mechanism may make this automatic (such as the case of
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* HTMLPurifier_Lexer_DOMLex). There are several implementations to choose
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* from.
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*
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* A lexer is HTML-oriented: it might work with XML, but it's not
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* recommended, as we adhere to a subset of the specification for optimization
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* reasons.
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*
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* This class should not be directly instantiated, but you may use create() to
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* retrieve a default copy of the lexer. Being a supertype, this class
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* does not actually define any implementation, but offers commonly used
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* convenience functions for subclasses.
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*
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* @note The unit tests will instantiate this class for testing purposes, as
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* many of the utility functions require a class to be instantiated.
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* Be careful when porting this class to PHP 5.
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*
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* @par
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*
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* @note
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* We use tokens rather than create a DOM representation because DOM would:
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*
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* @par
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* -# Require more processing power to create,
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* -# Require recursion to iterate,
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* -# Must be compatible with PHP 5's DOM (otherwise duplication),
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* -# Has the entire document structure (html and body not needed), and
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* -# Has unknown readability improvement.
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*
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* @par
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* What the last item means is that the functions for manipulating tokens are
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* already fairly compact, and when well-commented, more abstraction may not
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* be needed.
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*
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* @see HTMLPurifier_Token
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*/
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class HTMLPurifier_Lexer
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{
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/**
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* Lexes an HTML string into tokens.
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*
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* @param $string String HTML.
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* @return HTMLPurifier_Token array representation of HTML.
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*/
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function tokenizeHTML($string, $config = null) {
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trigger_error('Call to abstract class', E_USER_ERROR);
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}
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/**
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* Retrieves or sets the default Lexer as a Prototype Factory.
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*
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* Depending on what PHP version you are running, the abstract base
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* Lexer class will determine which concrete Lexer is best for you:
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* HTMLPurifier_Lexer_DirectLex for PHP 4, and HTMLPurifier_Lexer_DOMLex
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* for PHP 5 and beyond.
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*
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* Passing the optional prototype lexer parameter will override the
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* default with your own implementation. A copy/reference of the prototype
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* lexer will now be returned when you request a new lexer.
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*
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* @note
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* Though it is possible to call this factory method from subclasses,
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* such usage is not recommended.
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*
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* @param $prototype Optional prototype lexer.
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* @return Concrete lexer.
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*/
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function create($prototype = null) {
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// we don't really care if it's a reference or a copy
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static $lexer = null;
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if ($prototype) {
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$lexer = $prototype;
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}
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if (empty($lexer)) {
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if (version_compare(PHP_VERSION, '5', '>=')) {
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require_once 'HTMLPurifier/Lexer/DOMLex.php';
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$lexer = new HTMLPurifier_Lexer_DOMLex();
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} else {
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require_once 'HTMLPurifier/Lexer/DirectLex.php';
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$lexer = new HTMLPurifier_Lexer_DirectLex();
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}
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}
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return $lexer;
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}
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/**
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* Decimal to parsed string conversion table for special entities.
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* @protected
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*/
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var $_special_dec2str =
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array(
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34 => '"',
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38 => '&',
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39 => "'",
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60 => '<',
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62 => '>'
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);
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/**
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* Stripped entity names to decimal conversion table for special entities.
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* @protected
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*/
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var $_special_ent2dec =
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array(
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'quot' => 34,
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'amp' => 38,
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'lt' => 60,
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'gt' => 62
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);
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/**
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* Most common entity to raw value conversion table for special entities.
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* @protected
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*/
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var $_special_entity2str =
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array(
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'"' => '"',
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'&' => '&',
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'<' => '<',
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'>' => '>',
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''' => "'",
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''' => "'",
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''' => "'"
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);
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/**
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* Callback regex string for parsing entities.
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* @protected
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*/
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var $_substituteEntitiesRegex =
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'/&(?:[#]x([a-fA-F0-9]+)|[#]0*(\d+)|([A-Za-z]+));?/';
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// 1. hex 2. dec 3. string
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/**
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* Substitutes non-special entities with their parsed equivalents. Since
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* running this whenever you have parsed character is t3h 5uck, we run
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* it before everything else.
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*
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* @protected
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* @param $string String to have non-special entities parsed.
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* @returns Parsed string.
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*/
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function substituteNonSpecialEntities($string) {
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// it will try to detect missing semicolons, but don't rely on it
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return preg_replace_callback(
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$this->_substituteEntitiesRegex,
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array($this, 'nonSpecialEntityCallback'),
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$string
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);
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}
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/**
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* Callback function for substituteNonSpecialEntities() that does the work.
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*
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* @warning Though this is public in order to let the callback happen,
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* calling it directly is not recommended.
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* @param $matches PCRE matches array, with 0 the entire match, and
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* either index 1, 2 or 3 set with a hex value, dec value,
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* or string (respectively).
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* @returns Replacement string.
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* @todo Implement string translations
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*/
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function nonSpecialEntityCallback($matches) {
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// replaces all but big five
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$entity = $matches[0];
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$is_num = (@$matches[0][1] === '#');
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if ($is_num) {
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$is_hex = (@$entity[2] === 'x');
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$int = $is_hex ? hexdec($matches[1]) : (int) $matches[2];
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if (isset($this->_special_dec2str[$int])) return $entity;
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return chr($int);
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} else {
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if (isset($this->_special_ent2dec[$matches[3]])) return $entity;
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if (!$this->_entity_lookup) {
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require_once 'HTMLPurifier/EntityLookup.php';
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$this->_entity_lookup = HTMLPurifier_EntityLookup::instance();
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}
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if (isset($this->_entity_lookup->table[$matches[3]])) {
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return $this->_entity_lookup->table[$matches[3]];
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} else {
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return $entity;
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}
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}
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}
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/**
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* Contains a copy of the EntityLookup table.
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* @protected
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*/
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var $_entity_lookup;
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/**
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* Translates CDATA sections into regular sections (through escaping).
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*
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* @protected
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* @param $string HTML string to process.
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* @returns HTML with CDATA sections escaped.
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*/
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function escapeCDATA($string) {
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return preg_replace_callback(
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'/<!\[CDATA\[(.+?)\]\]>/',
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array('HTMLPurifier_Lexer', 'CDATACallback'),
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$string
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);
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}
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/**
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* Callback function for escapeCDATA() that does the work.
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*
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* @warning Though this is public in order to let the callback happen,
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* calling it directly is not recommended.
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* @params $matches PCRE matches array, with index 0 the entire match
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* and 1 the inside of the CDATA section.
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* @returns Escaped internals of the CDATA section.
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*/
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function CDATACallback($matches) {
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// not exactly sure why the character set is needed, but whatever
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return htmlspecialchars($matches[1], ENT_COMPAT, 'UTF-8');
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}
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/**
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* Takes a string of HTML (fragment or document) and returns the content
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*/
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function extractBody($html, $return_bool = false) {
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$matches = array();
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$result = preg_match('!<body[^>]*>(.+?)</body>!is', $html, $matches);
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if ($return_bool) return $result;
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if ($result) {
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return $matches[1];
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} else {
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return $html;
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}
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}
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}
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?>
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