284 lines
		
	
	
		
			8.8 KiB
		
	
	
	
		
			PHP
		
	
	
			
		
		
	
	
			284 lines
		
	
	
		
			8.8 KiB
		
	
	
	
		
			PHP
		
	
	
<?php
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/**
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 * Injects tokens into the document while parsing for well-formedness.
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 * This enables "formatter-like" functionality such as auto-paragraphing,
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 * smiley-ification and linkification to take place.
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 *
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 * A note on how handlers create changes; this is done by assigning a new
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 * value to the $token reference. These values can take a variety of forms and
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 * are best described HTMLPurifier_Strategy_MakeWellFormed->processToken()
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 * documentation.
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 *
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 * @todo Allow injectors to request a re-run on their output. This
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 *       would help if an operation is recursive.
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 */
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abstract class HTMLPurifier_Injector
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{
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    /**
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     * Advisory name of injector, this is for friendly error messages.
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     * @type string
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     */
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    public $name;
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    /**
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     * @type HTMLPurifier_HTMLDefinition
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     */
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    protected $htmlDefinition;
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    /**
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     * Reference to CurrentNesting variable in Context. This is an array
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     * list of tokens that we are currently "inside"
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     * @type array
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     */
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    protected $currentNesting;
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    /**
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     * Reference to current token.
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     * @type HTMLPurifier_Token
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     */
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    protected $currentToken;
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    /**
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     * Reference to InputZipper variable in Context.
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     * @type HTMLPurifier_Zipper
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     */
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    protected $inputZipper;
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    /**
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     * Array of elements and attributes this injector creates and therefore
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     * need to be allowed by the definition. Takes form of
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     * array('element' => array('attr', 'attr2'), 'element2')
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     * @type array
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     */
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    public $needed = array();
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    /**
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     * Number of elements to rewind backwards (relative).
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     * @type bool|int
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     */
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    protected $rewindOffset = false;
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    /**
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     * Rewind to a spot to re-perform processing. This is useful if you
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     * deleted a node, and now need to see if this change affected any
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     * earlier nodes. Rewinding does not affect other injectors, and can
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     * result in infinite loops if not used carefully.
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     * @param bool|int $offset
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     * @warning HTML Purifier will prevent you from fast-forwarding with this
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     *          function.
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     */
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    public function rewindOffset($offset)
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    {
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        $this->rewindOffset = $offset;
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    }
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    /**
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     * Retrieves rewind offset, and then unsets it.
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     * @return bool|int
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     */
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    public function getRewindOffset()
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    {
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        $r = $this->rewindOffset;
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        $this->rewindOffset = false;
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        return $r;
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    }
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    /**
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     * Prepares the injector by giving it the config and context objects:
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     * this allows references to important variables to be made within
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     * the injector. This function also checks if the HTML environment
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     * will work with the Injector (see checkNeeded()).
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     * @param HTMLPurifier_Config $config
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     * @param HTMLPurifier_Context $context
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     * @return bool|string Boolean false if success, string of missing needed element/attribute if failure
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     */
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    public function prepare($config, $context)
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    {
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        $this->htmlDefinition = $config->getHTMLDefinition();
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        // Even though this might fail, some unit tests ignore this and
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        // still test checkNeeded, so be careful. Maybe get rid of that
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        // dependency.
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        $result = $this->checkNeeded($config);
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        if ($result !== false) {
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            return $result;
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        }
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        $this->currentNesting =& $context->get('CurrentNesting');
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        $this->currentToken   =& $context->get('CurrentToken');
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        $this->inputZipper    =& $context->get('InputZipper');
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        return false;
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    }
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    /**
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     * This function checks if the HTML environment
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     * will work with the Injector: if p tags are not allowed, the
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     * Auto-Paragraphing injector should not be enabled.
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     * @param HTMLPurifier_Config $config
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     * @return bool|string Boolean false if success, string of missing needed element/attribute if failure
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     */
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    public function checkNeeded($config)
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    {
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        $def = $config->getHTMLDefinition();
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        foreach ($this->needed as $element => $attributes) {
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            if (is_int($element)) {
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                $element = $attributes;
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            }
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            if (!isset($def->info[$element])) {
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                return $element;
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            }
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            if (!is_array($attributes)) {
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                continue;
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            }
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            foreach ($attributes as $name) {
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                if (!isset($def->info[$element]->attr[$name])) {
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                    return "$element.$name";
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                }
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            }
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        }
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        return false;
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    }
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    /**
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     * Tests if the context node allows a certain element
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     * @param string $name Name of element to test for
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     * @return bool True if element is allowed, false if it is not
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     */
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    public function allowsElement($name)
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    {
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        if (!empty($this->currentNesting)) {
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            $parent_token = array_pop($this->currentNesting);
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            $this->currentNesting[] = $parent_token;
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            $parent = $this->htmlDefinition->info[$parent_token->name];
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        } else {
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            $parent = $this->htmlDefinition->info_parent_def;
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        }
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        if (!isset($parent->child->elements[$name]) || isset($parent->excludes[$name])) {
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            return false;
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        }
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        // check for exclusion
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        if (!empty($this->currentNesting)) {
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            for ($i = count($this->currentNesting) - 2; $i >= 0; $i--) {
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                $node = $this->currentNesting[$i];
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                $def  = $this->htmlDefinition->info[$node->name];
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                if (isset($def->excludes[$name])) {
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                    return false;
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                }
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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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     * Iterator function, which starts with the next token and continues until
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     * you reach the end of the input tokens.
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     * @warning Please prevent previous references from interfering with this
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     *          functions by setting $i = null beforehand!
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     * @param int $i Current integer index variable for inputTokens
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     * @param HTMLPurifier_Token $current Current token variable.
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     *          Do NOT use $token, as that variable is also a reference
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     * @return bool
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     */
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    protected function forward(&$i, &$current)
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    {
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        if ($i === null) {
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            $i = count($this->inputZipper->back) - 1;
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        } else {
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            $i--;
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        }
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        if ($i < 0) {
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            return false;
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        }
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        $current = $this->inputZipper->back[$i];
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        return true;
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    }
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    /**
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     * Similar to _forward, but accepts a third parameter $nesting (which
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     * should be initialized at 0) and stops when we hit the end tag
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     * for the node $this->inputIndex starts in.
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     * @param int $i Current integer index variable for inputTokens
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     * @param HTMLPurifier_Token $current Current token variable.
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     *          Do NOT use $token, as that variable is also a reference
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     * @param int $nesting
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     * @return bool
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     */
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    protected function forwardUntilEndToken(&$i, &$current, &$nesting)
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    {
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        $result = $this->forward($i, $current);
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        if (!$result) {
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            return false;
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        }
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        if ($nesting === null) {
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            $nesting = 0;
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        }
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        if ($current instanceof HTMLPurifier_Token_Start) {
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            $nesting++;
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        } elseif ($current instanceof HTMLPurifier_Token_End) {
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            if ($nesting <= 0) {
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                return false;
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            }
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            $nesting--;
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        }
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        return true;
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    }
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    /**
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     * Iterator function, starts with the previous token and continues until
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     * you reach the beginning of input tokens.
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     * @warning Please prevent previous references from interfering with this
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     *          functions by setting $i = null beforehand!
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     * @param int $i Current integer index variable for inputTokens
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     * @param HTMLPurifier_Token $current Current token variable.
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     *          Do NOT use $token, as that variable is also a reference
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     * @return bool
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     */
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    protected function backward(&$i, &$current)
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    {
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        if ($i === null) {
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            $i = count($this->inputZipper->front) - 1;
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        } else {
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            $i--;
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        }
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        if ($i < 0) {
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            return false;
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        }
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        $current = $this->inputZipper->front[$i];
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        return true;
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    }
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    /**
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     * Handler that is called when a text token is processed
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     */
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    public function handleText(&$token)
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    {
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    }
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    /**
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     * Handler that is called when a start or empty token is processed
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     */
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    public function handleElement(&$token)
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    {
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    }
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    /**
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     * Handler that is called when an end token is processed
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     */
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    public function handleEnd(&$token)
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    {
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        $this->notifyEnd($token);
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    }
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    /**
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     * Notifier that is called when an end token is processed
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     * @param HTMLPurifier_Token $token Current token variable.
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     * @note This differs from handlers in that the token is read-only
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     * @deprecated
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     */
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    public function notifyEnd($token)
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    {
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    }
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}
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// vim: et sw=4 sts=4
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