<?php /** * Takes tokens makes them well-formed (balance end tags, etc.) * * Specification of the armor attributes this strategy uses: * * - MakeWellFormed_TagClosedError: This armor field is used to * suppress tag closed errors for certain tokens [TagClosedSuppress], * in particular, if a tag was generated automatically by HTML * Purifier, we may rely on our infrastructure to close it for us * and shouldn't report an error to the user [TagClosedAuto]. */ class HTMLPurifier_Strategy_MakeWellFormed extends HTMLPurifier_Strategy { /** * Array stream of tokens being processed. * @type HTMLPurifier_Token[] */ protected $tokens; /** * Current token. * @type HTMLPurifier_Token */ protected $token; /** * Zipper managing the true state. * @type HTMLPurifier_Zipper */ protected $zipper; /** * Current nesting of elements. * @type array */ protected $stack; /** * Injectors active in this stream processing. * @type HTMLPurifier_Injector[] */ protected $injectors; /** * Current instance of HTMLPurifier_Config. * @type HTMLPurifier_Config */ protected $config; /** * Current instance of HTMLPurifier_Context. * @type HTMLPurifier_Context */ protected $context; /** * @param HTMLPurifier_Token[] $tokens * @param HTMLPurifier_Config $config * @param HTMLPurifier_Context $context * @return HTMLPurifier_Token[] * @throws HTMLPurifier_Exception */ public function execute($tokens, $config, $context) { $definition = $config->getHTMLDefinition(); // local variables $generator = new HTMLPurifier_Generator($config, $context); $escape_invalid_tags = $config->get('Core.EscapeInvalidTags'); // used for autoclose early abortion $global_parent_allowed_elements = $definition->info_parent_def->child->getAllowedElements($config); $e = $context->get('ErrorCollector', true); $i = false; // injector index list($zipper, $token) = HTMLPurifier_Zipper::fromArray($tokens); if ($token === NULL) { return array(); } $reprocess = false; // whether or not to reprocess the same token $stack = array(); // member variables $this->stack =& $stack; $this->tokens =& $tokens; $this->token =& $token; $this->zipper =& $zipper; $this->config = $config; $this->context = $context; // context variables $context->register('CurrentNesting', $stack); $context->register('InputZipper', $zipper); $context->register('CurrentToken', $token); // -- begin INJECTOR -- $this->injectors = array(); $injectors = $config->getBatch('AutoFormat'); $def_injectors = $definition->info_injector; $custom_injectors = $injectors['Custom']; unset($injectors['Custom']); // special case foreach ($injectors as $injector => $b) { // XXX: Fix with a legitimate lookup table of enabled filters if (strpos($injector, '.') !== false) { continue; } $injector = "HTMLPurifier_Injector_$injector"; if (!$b) { continue; } $this->injectors[] = new $injector; } foreach ($def_injectors as $injector) { // assumed to be objects $this->injectors[] = $injector; } foreach ($custom_injectors as $injector) { if (!$injector) { continue; } if (is_string($injector)) { $injector = "HTMLPurifier_Injector_$injector"; $injector = new $injector; } $this->injectors[] = $injector; } // give the injectors references to the definition and context // variables for performance reasons foreach ($this->injectors as $ix => $injector) { $error = $injector->prepare($config, $context); if (!$error) { continue; } array_splice($this->injectors, $ix, 1); // rm the injector trigger_error("Cannot enable {$injector->name} injector because $error is not allowed", E_USER_WARNING); } // -- end INJECTOR -- // a note on reprocessing: // In order to reduce code duplication, whenever some code needs // to make HTML changes in order to make things "correct", the // new HTML gets sent through the purifier, regardless of its // status. This means that if we add a start token, because it // was totally necessary, we don't have to update nesting; we just // punt ($reprocess = true; continue;) and it does that for us. // isset is in loop because $tokens size changes during loop exec for (;; // only increment if we don't need to reprocess $reprocess ? $reprocess = false : $token = $zipper->next($token)) { // check for a rewind if (is_int($i)) { // possibility: disable rewinding if the current token has a // rewind set on it already. This would offer protection from // infinite loop, but might hinder some advanced rewinding. $rewind_offset = $this->injectors[$i]->getRewindOffset(); if (is_int($rewind_offset)) { for ($j = 0; $j < $rewind_offset; $j++) { if (empty($zipper->front)) break; $token = $zipper->prev($token); // indicate that other injectors should not process this token, // but we need to reprocess it unset($token->skip[$i]); $token->rewind = $i; if ($token instanceof HTMLPurifier_Token_Start) { array_pop($this->stack); } elseif ($token instanceof HTMLPurifier_Token_End) { $this->stack[] = $token->start; } } } $i = false; } // handle case of document end if ($token === NULL) { // kill processing if stack is empty if (empty($this->stack)) { break; } // peek $top_nesting = array_pop($this->stack); $this->stack[] = $top_nesting; // send error [TagClosedSuppress] if ($e && !isset($top_nesting->armor['MakeWellFormed_TagClosedError'])) { $e->send(E_NOTICE, 'Strategy_MakeWellFormed: Tag closed by document end', $top_nesting); } // append, don't splice, since this is the end $token = new HTMLPurifier_Token_End($top_nesting->name); // punt! $reprocess = true; continue; } //echo '<br>'; printZipper($zipper, $token);//printTokens($this->stack); //flush(); // quick-check: if it's not a tag, no need to process if (empty($token->is_tag)) { if ($token instanceof HTMLPurifier_Token_Text) { foreach ($this->injectors as $i => $injector) { if (isset($token->skip[$i])) { continue; } if ($token->rewind !== null && $token->rewind !== $i) { continue; } // XXX fuckup $r = $token; $injector->handleText($r); $token = $this->processToken($r, $i); $reprocess = true; break; } } // another possibility is a comment continue; } if (isset($definition->info[$token->name])) { $type = $definition->info[$token->name]->child->type; } else { $type = false; // Type is unknown, treat accordingly } // quick tag checks: anything that's *not* an end tag $ok = false; if ($type === 'empty' && $token instanceof HTMLPurifier_Token_Start) { // claims to be a start tag but is empty $token = new HTMLPurifier_Token_Empty( $token->name, $token->attr, $token->line, $token->col, $token->armor ); $ok = true; } elseif ($type && $type !== 'empty' && $token instanceof HTMLPurifier_Token_Empty) { // claims to be empty but really is a start tag // NB: this assignment is required $old_token = $token; $token = new HTMLPurifier_Token_End($token->name); $token = $this->insertBefore( new HTMLPurifier_Token_Start($old_token->name, $old_token->attr, $old_token->line, $old_token->col, $old_token->armor) ); // punt (since we had to modify the input stream in a non-trivial way) $reprocess = true; continue; } elseif ($token instanceof HTMLPurifier_Token_Empty) { // real empty token $ok = true; } elseif ($token instanceof HTMLPurifier_Token_Start) { // start tag // ...unless they also have to close their parent if (!empty($this->stack)) { // Performance note: you might think that it's rather // inefficient, recalculating the autoclose information // for every tag that a token closes (since when we // do an autoclose, we push a new token into the // stream and then /process/ that, before // re-processing this token.) But this is // necessary, because an injector can make an // arbitrary transformations to the autoclosing // tokens we introduce, so things may have changed // in the meantime. Also, doing the inefficient thing is // "easy" to reason about (for certain perverse definitions // of "easy") $parent = array_pop($this->stack); $this->stack[] = $parent; $parent_def = null; $parent_elements = null; $autoclose = false; if (isset($definition->info[$parent->name])) { $parent_def = $definition->info[$parent->name]; $parent_elements = $parent_def->child->getAllowedElements($config); $autoclose = !isset($parent_elements[$token->name]); } if ($autoclose && $definition->info[$token->name]->wrap) { // Check if an element can be wrapped by another // element to make it valid in a context (for // example, <ul><ul> needs a <li> in between) $wrapname = $definition->info[$token->name]->wrap; $wrapdef = $definition->info[$wrapname]; $elements = $wrapdef->child->getAllowedElements($config); if (isset($elements[$token->name]) && isset($parent_elements[$wrapname])) { $newtoken = new HTMLPurifier_Token_Start($wrapname); $token = $this->insertBefore($newtoken); $reprocess = true; continue; } } $carryover = false; if ($autoclose && $parent_def->formatting) { $carryover = true; } if ($autoclose) { // check if this autoclose is doomed to fail // (this rechecks $parent, which his harmless) $autoclose_ok = isset($global_parent_allowed_elements[$token->name]); if (!$autoclose_ok) { foreach ($this->stack as $ancestor) { $elements = $definition->info[$ancestor->name]->child->getAllowedElements($config); if (isset($elements[$token->name])) { $autoclose_ok = true; break; } if ($definition->info[$token->name]->wrap) { $wrapname = $definition->info[$token->name]->wrap; $wrapdef = $definition->info[$wrapname]; $wrap_elements = $wrapdef->child->getAllowedElements($config); if (isset($wrap_elements[$token->name]) && isset($elements[$wrapname])) { $autoclose_ok = true; break; } } } } if ($autoclose_ok) { // errors need to be updated $new_token = new HTMLPurifier_Token_End($parent->name); $new_token->start = $parent; // [TagClosedSuppress] if ($e && !isset($parent->armor['MakeWellFormed_TagClosedError'])) { if (!$carryover) { $e->send(E_NOTICE, 'Strategy_MakeWellFormed: Tag auto closed', $parent); } else { $e->send(E_NOTICE, 'Strategy_MakeWellFormed: Tag carryover', $parent); } } if ($carryover) { $element = clone $parent; // [TagClosedAuto] $element->armor['MakeWellFormed_TagClosedError'] = true; $element->carryover = true; $token = $this->processToken(array($new_token, $token, $element)); } else { $token = $this->insertBefore($new_token); } } else { $token = $this->remove(); } $reprocess = true; continue; } } $ok = true; } if ($ok) { foreach ($this->injectors as $i => $injector) { if (isset($token->skip[$i])) { continue; } if ($token->rewind !== null && $token->rewind !== $i) { continue; } $r = $token; $injector->handleElement($r); $token = $this->processToken($r, $i); $reprocess = true; break; } if (!$reprocess) { // ah, nothing interesting happened; do normal processing if ($token instanceof HTMLPurifier_Token_Start) { $this->stack[] = $token; } elseif ($token instanceof HTMLPurifier_Token_End) { throw new HTMLPurifier_Exception( 'Improper handling of end tag in start code; possible error in MakeWellFormed' ); } } continue; } // sanity check: we should be dealing with a closing tag if (!$token instanceof HTMLPurifier_Token_End) { throw new HTMLPurifier_Exception('Unaccounted for tag token in input stream, bug in HTML Purifier'); } // make sure that we have something open if (empty($this->stack)) { if ($escape_invalid_tags) { if ($e) { $e->send(E_WARNING, 'Strategy_MakeWellFormed: Unnecessary end tag to text'); } $token = new HTMLPurifier_Token_Text($generator->generateFromToken($token)); } else { if ($e) { $e->send(E_WARNING, 'Strategy_MakeWellFormed: Unnecessary end tag removed'); } $token = $this->remove(); } $reprocess = true; continue; } // first, check for the simplest case: everything closes neatly. // Eventually, everything passes through here; if there are problems // we modify the input stream accordingly and then punt, so that // the tokens get processed again. $current_parent = array_pop($this->stack); if ($current_parent->name == $token->name) { $token->start = $current_parent; foreach ($this->injectors as $i => $injector) { if (isset($token->skip[$i])) { continue; } if ($token->rewind !== null && $token->rewind !== $i) { continue; } $r = $token; $injector->handleEnd($r); $token = $this->processToken($r, $i); $this->stack[] = $current_parent; $reprocess = true; break; } continue; } // okay, so we're trying to close the wrong tag // undo the pop previous pop $this->stack[] = $current_parent; // scroll back the entire nest, trying to find our tag. // (feature could be to specify how far you'd like to go) $size = count($this->stack); // -2 because -1 is the last element, but we already checked that $skipped_tags = false; for ($j = $size - 2; $j >= 0; $j--) { if ($this->stack[$j]->name == $token->name) { $skipped_tags = array_slice($this->stack, $j); break; } } // we didn't find the tag, so remove if ($skipped_tags === false) { if ($escape_invalid_tags) { if ($e) { $e->send(E_WARNING, 'Strategy_MakeWellFormed: Stray end tag to text'); } $token = new HTMLPurifier_Token_Text($generator->generateFromToken($token)); } else { if ($e) { $e->send(E_WARNING, 'Strategy_MakeWellFormed: Stray end tag removed'); } $token = $this->remove(); } $reprocess = true; continue; } // do errors, in REVERSE $j order: a,b,c with </a></b></c> $c = count($skipped_tags); if ($e) { for ($j = $c - 1; $j > 0; $j--) { // notice we exclude $j == 0, i.e. the current ending tag, from // the errors... [TagClosedSuppress] if (!isset($skipped_tags[$j]->armor['MakeWellFormed_TagClosedError'])) { $e->send(E_NOTICE, 'Strategy_MakeWellFormed: Tag closed by element end', $skipped_tags[$j]); } } } // insert tags, in FORWARD $j order: c,b,a with </a></b></c> $replace = array($token); for ($j = 1; $j < $c; $j++) { // ...as well as from the insertions $new_token = new HTMLPurifier_Token_End($skipped_tags[$j]->name); $new_token->start = $skipped_tags[$j]; array_unshift($replace, $new_token); if (isset($definition->info[$new_token->name]) && $definition->info[$new_token->name]->formatting) { // [TagClosedAuto] $element = clone $skipped_tags[$j]; $element->carryover = true; $element->armor['MakeWellFormed_TagClosedError'] = true; $replace[] = $element; } } $token = $this->processToken($replace); $reprocess = true; continue; } $context->destroy('CurrentToken'); $context->destroy('CurrentNesting'); $context->destroy('InputZipper'); unset($this->injectors, $this->stack, $this->tokens); return $zipper->toArray($token); } /** * Processes arbitrary token values for complicated substitution patterns. * In general: * * If $token is an array, it is a list of tokens to substitute for the * current token. These tokens then get individually processed. If there * is a leading integer in the list, that integer determines how many * tokens from the stream should be removed. * * If $token is a regular token, it is swapped with the current token. * * If $token is false, the current token is deleted. * * If $token is an integer, that number of tokens (with the first token * being the current one) will be deleted. * * @param HTMLPurifier_Token|array|int|bool $token Token substitution value * @param HTMLPurifier_Injector|int $injector Injector that performed the substitution; default is if * this is not an injector related operation. * @throws HTMLPurifier_Exception */ protected function processToken($token, $injector = -1) { // normalize forms of token if (is_object($token)) { $token = array(1, $token); } if (is_int($token)) { $token = array($token); } if ($token === false) { $token = array(1); } if (!is_array($token)) { throw new HTMLPurifier_Exception('Invalid token type from injector'); } if (!is_int($token[0])) { array_unshift($token, 1); } if ($token[0] === 0) { throw new HTMLPurifier_Exception('Deleting zero tokens is not valid'); } // $token is now an array with the following form: // array(number nodes to delete, new node 1, new node 2, ...) $delete = array_shift($token); list($old, $r) = $this->zipper->splice($this->token, $delete, $token); if ($injector > -1) { // determine appropriate skips $oldskip = isset($old[0]) ? $old[0]->skip : array(); foreach ($token as $object) { $object->skip = $oldskip; $object->skip[$injector] = true; } } return $r; } /** * Inserts a token before the current token. Cursor now points to * this token. You must reprocess after this. * @param HTMLPurifier_Token $token */ private function insertBefore($token) { // NB not $this->zipper->insertBefore(), due to positioning // differences $splice = $this->zipper->splice($this->token, 0, array($token)); return $splice[1]; } /** * Removes current token. Cursor now points to new token occupying previously * occupied space. You must reprocess after this. */ private function remove() { return $this->zipper->delete(); } } // vim: et sw=4 sts=4