mirror of
https://github.com/ezyang/htmlpurifier.git
synced 2024-12-22 08:21:52 +00:00
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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