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https://github.com/ezyang/htmlpurifier.git
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965be3bd73
The MakeWellFormed strategy uses metadata from HTMLDefinition in order to determine whether or not tokens need to be converted or tags need to be auto-closed. While this functionality is good to have, it is by no means essential, and MakeWellFormed should not error when this information is not available. Signed-off-by: Edward Z. Yang <edwardzyang@thewritingpot.com>
388 lines
16 KiB
PHP
388 lines
16 KiB
PHP
<?php
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/**
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* Takes tokens makes them well-formed (balance end tags, etc.)
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*/
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class HTMLPurifier_Strategy_MakeWellFormed extends HTMLPurifier_Strategy
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{
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/**
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* Locally shared variable references
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*/
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protected $inputTokens, $inputIndex, $outputTokens, $currentNesting,
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$currentInjector, $injectors;
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public function execute($tokens, $config, $context) {
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$definition = $config->getHTMLDefinition();
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// local variables
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$generator = new HTMLPurifier_Generator($config, $context);
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$escape_invalid_tags = $config->get('Core', 'EscapeInvalidTags');
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$e = $context->get('ErrorCollector', true);
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// member variables
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$this->currentNesting = array();
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$this->inputIndex = false;
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$this->inputTokens =& $tokens;
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// context variables
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$context->register('CurrentNesting', $this->currentNesting);
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$context->register('InputIndex', $this->inputIndex);
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$context->register('InputTokens', $tokens);
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// -- begin INJECTOR --
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$this->injectors = array();
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$injectors = $config->getBatch('AutoFormat');
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$def_injectors = $definition->info_injector;
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$custom_injectors = $injectors['Custom'];
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unset($injectors['Custom']); // special case
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foreach ($injectors as $injector => $b) {
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$injector = "HTMLPurifier_Injector_$injector";
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if (!$b) continue;
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$this->injectors[] = new $injector;
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}
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foreach ($def_injectors as $injector) {
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// assumed to be objects
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$this->injectors[] = $injector;
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}
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foreach ($custom_injectors as $injector) {
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if (is_string($injector)) {
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$injector = "HTMLPurifier_Injector_$injector";
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$injector = new $injector;
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}
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$this->injectors[] = $injector;
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}
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// array index of the injector that resulted in an array
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// substitution. This enables processTokens() to know which
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// injectors are affected by the added tokens and which are
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// not (namely, the ones after the current injector are not
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// affected)
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$this->currentInjector = false;
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// give the injectors references to the definition and context
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// variables for performance reasons
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foreach ($this->injectors as $i => $injector) {
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$error = $injector->prepare($config, $context);
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if (!$error) continue;
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array_splice($this->injectors, $i, 1); // rm the injector
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trigger_error("Cannot enable {$injector->name} injector because $error is not allowed", E_USER_WARNING);
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}
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// warning: most foreach loops follow the convention $i => $injector.
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// Don't define these as loop-wide variables, please!
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// -- end INJECTOR --
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$token = false;
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$context->register('CurrentToken', $token);
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// isset is in loop because $tokens size changes during loop exec
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for ($this->inputIndex = 0; isset($tokens[$this->inputIndex]); $this->inputIndex++) {
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// if all goes well, this token will be passed through unharmed
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$token = $tokens[$this->inputIndex];
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//echo '<hr>';
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//printTokens($tokens, $this->inputIndex);
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//var_dump($this->currentNesting);
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foreach ($this->injectors as $injector) {
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if ($injector->skip > 0) $injector->skip--;
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}
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// quick-check: if it's not a tag, no need to process
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if (empty( $token->is_tag )) {
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if ($token instanceof HTMLPurifier_Token_Text) {
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// injector handler code; duplicated for performance reasons
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foreach ($this->injectors as $i => $injector) {
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if (!$injector->skip) $injector->handleText($token);
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if (is_array($token) || is_int($token)) {
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$this->currentInjector = $i;
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break;
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}
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}
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}
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$this->processToken($token, $config, $context);
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continue;
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}
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if (isset($definition->info[$token->name])) {
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$type = $definition->info[$token->name]->child->type;
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} else {
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$type = false; // Type is unknown, treat accordingly
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}
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// quick tag checks: anything that's *not* an end tag
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$ok = false;
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if ($type === 'empty' && $token instanceof HTMLPurifier_Token_Start) {
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// test if it claims to be a start tag but is empty
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$token = new HTMLPurifier_Token_Empty($token->name, $token->attr);
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$ok = true;
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} elseif ($type && $type !== 'empty' && $token instanceof HTMLPurifier_Token_Empty) {
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// claims to be empty but really is a start tag
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$token = array(
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new HTMLPurifier_Token_Start($token->name, $token->attr),
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new HTMLPurifier_Token_End($token->name)
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);
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$ok = true;
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} elseif ($token instanceof HTMLPurifier_Token_Empty) {
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// real empty token
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$ok = true;
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} elseif ($token instanceof HTMLPurifier_Token_Start) {
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// start tag
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// ...unless they also have to close their parent
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if (!empty($this->currentNesting)) {
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$parent = array_pop($this->currentNesting);
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if (isset($definition->info[$parent->name])) {
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$elements = $definition->info[$parent->name]->child->elements;
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$autoclose = !isset($elements[$token->name]);
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} else {
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$autoclose = false;
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}
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if ($autoclose) {
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if ($e) $e->send(E_NOTICE, 'Strategy_MakeWellFormed: Tag auto closed', $parent);
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// insert parent end tag before this tag;
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// end tag isn't processed, but this tag is processed again
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$new_token = new HTMLPurifier_Token_End($parent->name);
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$new_token->start = $parent;
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$this->insertBefore($new_token);
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continue;
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}
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$this->currentNesting[] = $parent; // undo the pop
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}
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$ok = true;
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}
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// injector handler code; duplicated for performance reasons
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if ($ok) {
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foreach ($this->injectors as $i => $injector) {
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if (!$injector->skip) $injector->handleElement($token);
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if (is_array($token) || is_int($token)) {
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$this->currentInjector = $i;
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break;
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}
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}
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$this->processToken($token, $config, $context);
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continue;
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}
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// sanity check: we should be dealing with a closing tag
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if (!$token instanceof HTMLPurifier_Token_End) {
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$this->remove();
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continue;
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}
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// make sure that we have something open
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if (empty($this->currentNesting)) {
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if ($escape_invalid_tags) {
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if ($e) $e->send(E_WARNING, 'Strategy_MakeWellFormed: Unnecessary end tag to text');
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$this->swap(new HTMLPurifier_Token_Text(
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$generator->generateFromToken($token)
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));
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} else {
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$this->remove();
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if ($e) $e->send(E_WARNING, 'Strategy_MakeWellFormed: Unnecessary end tag removed');
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}
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continue;
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}
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// first, check for the simplest case: everything closes neatly
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$current_parent = array_pop($this->currentNesting);
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if ($current_parent->name == $token->name) {
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$token->start = $current_parent;
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foreach ($this->injectors as $i => $injector) {
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$injector->notifyEnd($token);
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}
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continue;
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}
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// okay, so we're trying to close the wrong tag
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// undo the pop previous pop
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$this->currentNesting[] = $current_parent;
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// scroll back the entire nest, trying to find our tag.
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// (feature could be to specify how far you'd like to go)
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$size = count($this->currentNesting);
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// -2 because -1 is the last element, but we already checked that
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$skipped_tags = false;
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for ($i = $size - 2; $i >= 0; $i--) {
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if ($this->currentNesting[$i]->name == $token->name) {
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// current nesting is modified
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$skipped_tags = array_splice($this->currentNesting, $i);
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break;
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}
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}
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// we still didn't find the tag, so remove
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if ($skipped_tags === false) {
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if ($escape_invalid_tags) {
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$this->swap(new HTMLPurifier_Token_Text(
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$generator->generateFromToken($token)
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));
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if ($e) $e->send(E_WARNING, 'Strategy_MakeWellFormed: Stray end tag to text');
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} else {
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$this->remove();
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if ($e) $e->send(E_WARNING, 'Strategy_MakeWellFormed: Stray end tag removed');
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}
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continue;
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}
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// okay, we found it, close all the skipped tags
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// note that skipped tags contains the element we need closed
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$this->remove();
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for ($i = count($skipped_tags) - 1; $i >= 0; $i--) {
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// please don't redefine $i!
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if ($i && $e && !isset($skipped_tags[$i]->armor['MakeWellFormed_TagClosedError'])) {
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$e->send(E_NOTICE, 'Strategy_MakeWellFormed: Tag closed by element end', $skipped_tags[$i]);
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}
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$new_token = new HTMLPurifier_Token_End($skipped_tags[$i]->name);
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$new_token->start = $skipped_tags[$i];
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$this->insertAfter($new_token);
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//printTokens($tokens, $this->inputIndex);
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//var_dump($this->currentNesting);
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foreach ($this->injectors as $injector) {
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$injector->notifyEnd($new_token);
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}
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}
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}
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$context->destroy('CurrentNesting');
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$context->destroy('InputTokens');
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$context->destroy('InputIndex');
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$context->destroy('CurrentToken');
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// we're at the end now, fix all still unclosed tags (this is
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// duplicated from the end of the loop with some slight modifications)
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// not using $skipped_tags since it would invariably be all of them
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if (!empty($this->currentNesting)) {
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for ($i = count($this->currentNesting) - 1; $i >= 0; $i--) {
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// please don't redefine $i!
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if ($e && !isset($this->currentNesting[$i]->armor['MakeWellFormed_TagClosedError'])) {
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$e->send(E_NOTICE, 'Strategy_MakeWellFormed: Tag closed by document end', $this->currentNesting[$i]);
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}
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// instead of splice, since we know this is the end
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$tokens[] = $new_token = new HTMLPurifier_Token_End($this->currentNesting[$i]->name);
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$new_token->start = $this->currentNesting[$i];
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foreach ($this->injectors as $injector) {
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$injector->notifyEnd($new_token);
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}
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}
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}
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unset($this->outputTokens, $this->injectors, $this->currentInjector,
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$this->currentNesting, $this->inputTokens, $this->inputIndex);
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return $tokens;
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}
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/**
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* Inserts a token before the current token. Cursor now points to this token.
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*/
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protected function insertBefore($token) {
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array_splice($this->inputTokens, $this->inputIndex, 0, array($token));
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}
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/**
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* Inserts a token after the current token. Cursor now points to this token.
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*/
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protected function insertAfter($token) {
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array_splice($this->inputTokens, ++$this->inputIndex, 0, array($token));
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}
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/**
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* Removes current token. Cursor now points to previous token.
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*/
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protected function remove() {
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array_splice($this->inputTokens, $this->inputIndex--, 1);
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}
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/**
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* Swap current token with new token. Cursor points to new token (no change).
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*/
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protected function swap($token) {
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array_splice($this->inputTokens, $this->inputIndex, 1, array($token));
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}
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/**
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* Processes arbitrary token values for complicated substitution patterns.
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* In general:
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*
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* If $token is an array, it is a list of tokens to substitute for the
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* current token. These tokens then get individually processed.
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*
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* If $token is a regular token, it is swapped with the current token,
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* and the stack is updated.
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*
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* If $token is false, the current token is deleted.
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*/
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protected function processToken($token, $config, $context) {
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if (is_array($token) || is_int($token)) {
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// the original token was overloaded by an injector, time
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// to some fancy acrobatics
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if (is_array($token)) {
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array_splice($this->inputTokens, $this->inputIndex, 1, $token);
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} else {
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array_splice($this->inputTokens, $this->inputIndex, $token, array());
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}
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if ($this->injectors) {
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$rewind = $this->injectors[$this->currentInjector]->getRewind();
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if ($rewind < 0) $rewind = 0;
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if ($rewind !== false) {
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$offset = $this->inputIndex - $rewind;
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if ($this->injectors) {
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foreach ($this->injectors as $i => $injector) {
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if ($i == $this->currentInjector) {
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$injector->skip = 0;
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} else {
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$injector->skip += $offset;
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}
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}
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}
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for ($this->inputIndex--; $this->inputIndex >= $rewind; $this->inputIndex--) {
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$prev = $this->inputTokens[$this->inputIndex];
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if ($prev instanceof HTMLPurifier_Token_Start) array_pop($this->currentNesting);
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elseif ($prev instanceof HTMLPurifier_Token_End) $this->currentNesting[] = $prev->start;
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}
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$this->inputIndex++;
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} else {
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// adjust the injector skips based on the array substitution
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$offset = is_array($token) ? count($token) : 0;
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for ($i = 0; $i <= $this->currentInjector; $i++) {
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// because of the skip back, we need to add one more
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// for uninitialized injectors. I'm not exactly
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// sure why this is the case, but I think it has to
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// do with the fact that we're decrementing skips
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// before re-checking text
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if (!$this->injectors[$i]->skip) $this->injectors[$i]->skip++;
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$this->injectors[$i]->skip += $offset;
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}
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}
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}
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// ensure that we reprocess these tokens with the other injectors
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--$this->inputIndex;
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} elseif ($token) {
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// regular case
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$this->swap($token);
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if ($token instanceof HTMLPurifier_Token_Start) {
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$this->currentNesting[] = $token;
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} elseif ($token instanceof HTMLPurifier_Token_End) {
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// not actually used
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$token->start = array_pop($this->currentNesting);
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}
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} else {
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$this->remove();
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}
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}
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}
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