<?php /** * Takes tokens makes them well-formed (balance end tags, etc.) */ class HTMLPurifier_Strategy_MakeWellFormed extends HTMLPurifier_Strategy { /** * Array stream of tokens being processed. */ protected $tokens; /** * Current index in $tokens. */ protected $t; /** * Current nesting of elements. */ protected $stack; /** * Injectors active in this stream processing. */ protected $injectors; /** * Current instance of HTMLPurifier_Config. */ protected $config; /** * Current instance of HTMLPurifier_Context. */ protected $context; public function execute($tokens, $config, $context) { $definition = $config->getHTMLDefinition(); // local variables $generator = new HTMLPurifier_Generator($config, $context); $escape_invalid_tags = $config->get('Core.EscapeInvalidTags'); $e = $context->get('ErrorCollector', true); $t = false; // token index $i = false; // injector index $token = false; // the current token $reprocess = false; // whether or not to reprocess the same token $stack = array(); // member variables $this->stack =& $stack; $this->t =& $t; $this->tokens =& $tokens; $this->config = $config; $this->context = $context; // context variables $context->register('CurrentNesting', $stack); $context->register('InputIndex', $t); $context->register('InputTokens', $tokens); $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 $error is not allowed", E_USER_WARNING); } // -- end INJECTOR -- // a note on punting: // In order to reduce code duplication, whenever some code needs // to make HTML changes in order to make things "correct", the // new HTML gets sent through the purifier, regardless of its // status. This means that if we add a start token, because it // was totally necessary, we don't have to update nesting; we just // punt ($reprocess = true; continue;) and it does that for us. // isset is in loop because $tokens size changes during loop exec for ( $t = 0; $t == 0 || isset($tokens[$t - 1]); // only increment if we don't need to reprocess $reprocess ? $reprocess = false : $t++ ) { // check for a rewind if (is_int($i) && $i >= 0) { // 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_to = $this->injectors[$i]->getRewind(); if (is_int($rewind_to) && $rewind_to < $t) { if ($rewind_to < 0) $rewind_to = 0; while ($t > $rewind_to) { $t--; $prev = $tokens[$t]; // indicate that other injectors should not process this token, // but we need to reprocess it unset($prev->skip[$i]); $prev->rewind = $i; if ($prev instanceof HTMLPurifier_Token_Start) array_pop($this->stack); elseif ($prev instanceof HTMLPurifier_Token_End) $this->stack[] = $prev->start; } } $i = false; } // handle case of document end if (!isset($tokens[$t])) { // kill processing if stack is empty if (empty($this->stack)) break; // peek $top_nesting = array_pop($this->stack); $this->stack[] = $top_nesting; // send error if ($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 $tokens[] = new HTMLPurifier_Token_End($top_nesting->name); // punt! $reprocess = true; continue; } $token = $tokens[$t]; //echo '<br>'; printTokens($tokens, $t); printTokens($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; $injector->handleText($token); $this->processToken($token, $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); $ok = true; } elseif ($type && $type !== 'empty' && $token instanceof HTMLPurifier_Token_Empty) { // claims to be empty but really is a start tag $this->swap(new HTMLPurifier_Token_End($token->name)); $this->insertBefore(new HTMLPurifier_Token_Start($token->name, $token->attr)); // 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)) { $parent = array_pop($this->stack); $this->stack[] = $parent; if (isset($definition->info[$parent->name])) { $elements = $definition->info[$parent->name]->child->getAllowedElements($config); $autoclose = !isset($elements[$token->name]); } else { $autoclose = false; } if ($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); $parent_elements = $definition->info[$parent->name]->child->getAllowedElements($config); if (isset($elements[$token->name]) && isset($parent_elements[$wrapname])) { $newtoken = new HTMLPurifier_Token_Start($wrapname); $this->insertBefore($newtoken); $reprocess = true; continue; } } $carryover = false; if ($autoclose && $definition->info[$parent->name]->formatting) { $carryover = true; } if ($autoclose) { // errors need to be updated $new_token = new HTMLPurifier_Token_End($parent->name); $new_token->start = $parent; if ($carryover) { $element = clone $parent; $element->armor['MakeWellFormed_TagClosedError'] = true; $element->carryover = true; $this->processToken(array($new_token, $token, $element)); } else { $this->insertBefore($new_token); } 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); } } $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; $injector->handleElement($token); $this->processToken($token, $i); $reprocess = true; break; } if (!$reprocess) { // ah, nothing interesting happened; do normal processing $this->swap($token); 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'); $this->swap(new HTMLPurifier_Token_Text( $generator->generateFromToken($token) )); } else { $this->remove(); if ($e) $e->send(E_WARNING, 'Strategy_MakeWellFormed: Unnecessary end tag removed'); } $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; $injector->handleEnd($token); $this->processToken($token, $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) { $this->swap(new HTMLPurifier_Token_Text( $generator->generateFromToken($token) )); if ($e) $e->send(E_WARNING, 'Strategy_MakeWellFormed: Stray end tag to text'); } else { $this->remove(); if ($e) $e->send(E_WARNING, 'Strategy_MakeWellFormed: Stray end tag removed'); } $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 $j == 0, i.e. the current ending tag, from // the errors... if (!isset($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) { $element = clone $skipped_tags[$j]; $element->carryover = true; $element->armor['MakeWellFormed_TagClosedError'] = true; $replace[] = $element; } } $this->processToken($replace); $reprocess = true; continue; } $context->destroy('CurrentNesting'); $context->destroy('InputTokens'); $context->destroy('InputIndex'); $context->destroy('CurrentToken'); unset($this->injectors, $this->stack, $this->tokens, $this->t); return $tokens; } /** * 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 $token Token substitution value * @param $injector Injector that performed the substitution; default is if * this is not an injector related operation. */ protected function processToken($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); $old = array_splice($this->tokens, $this->t, $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; } } } /** * Inserts a token before the current token. Cursor now points to this token */ private function insertBefore($token) { array_splice($this->tokens, $this->t, 0, array($token)); } /** * Removes current token. Cursor now points to new token occupying previously * occupied space. */ private function remove() { array_splice($this->tokens, $this->t, 1); } /** * Swap current token with new token. Cursor points to new token (no change). */ private function swap($token) { $this->tokens[$this->t] = $token; } } // vim: et sw=4 sts=4