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<?php
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/**
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 * Custom validation class, accepts DTD child definitions
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 *
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 * @warning Currently this class is an all or nothing proposition, that is,
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 *          it will only give a bool return value.
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 */
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class HTMLPurifier_ChildDef_Custom extends HTMLPurifier_ChildDef
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{
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    /**
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     * @type string
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     */
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    public $type = 'custom';
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    /**
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     * @type bool
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     */
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    public $allow_empty = false;
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    /**
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     * Allowed child pattern as defined by the DTD.
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     * @type string
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     */
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    public $dtd_regex;
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    /**
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     * PCRE regex derived from $dtd_regex.
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     * @type string
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     */
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    private $_pcre_regex;
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    /**
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     * @param $dtd_regex Allowed child pattern from the DTD
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     */
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    public function __construct($dtd_regex)
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    {
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        $this->dtd_regex = $dtd_regex;
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        $this->_compileRegex();
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    }
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    /**
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     * Compiles the PCRE regex from a DTD regex ($dtd_regex to $_pcre_regex)
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     */
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    protected function _compileRegex()
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    {
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        $raw = str_replace(' ', '', $this->dtd_regex);
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        if ($raw[0] != '(') {
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            $raw = "($raw)";
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        }
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        $el = '[#a-zA-Z0-9_.-]+';
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        $reg = $raw;
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        // COMPLICATED! AND MIGHT BE BUGGY! I HAVE NO CLUE WHAT I'M
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        // DOING! Seriously: if there's problems, please report them.
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        // collect all elements into the $elements array
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        preg_match_all("/$el/", $reg, $matches);
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        foreach ($matches[0] as $match) {
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            $this->elements[$match] = true;
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        }
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        // setup all elements as parentheticals with leading commas
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        $reg = preg_replace("/$el/", '(,\\0)', $reg);
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        // remove commas when they were not solicited
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        $reg = preg_replace("/([^,(|]\(+),/", '\\1', $reg);
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        // remove all non-paranthetical commas: they are handled by first regex
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        $reg = preg_replace("/,\(/", '(', $reg);
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        $this->_pcre_regex = $reg;
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    }
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    /**
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     * @param HTMLPurifier_Node[] $children
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     * @param HTMLPurifier_Config $config
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     * @param HTMLPurifier_Context $context
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     * @return bool
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     */
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    public function validateChildren($children, $config, $context)
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    {
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        $list_of_children = '';
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        $nesting = 0; // depth into the nest
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        foreach ($children as $node) {
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            if (!empty($node->is_whitespace)) {
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                continue;
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            }
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            $list_of_children .= $node->name . ',';
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        }
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        // add leading comma to deal with stray comma declarations
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        $list_of_children = ',' . rtrim($list_of_children, ',');
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        $okay =
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            preg_match(
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                '/^,?' . $this->_pcre_regex . '$/',
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                $list_of_children
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            );
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        return (bool)$okay;
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    }
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}
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// vim: et sw=4 sts=4