diff options
Diffstat (limited to 'library/HTMLPurifier/Strategy/MakeWellFormed.php')
| -rw-r--r-- | library/HTMLPurifier/Strategy/MakeWellFormed.php | 475 |
1 files changed, 475 insertions, 0 deletions
diff --git a/library/HTMLPurifier/Strategy/MakeWellFormed.php b/library/HTMLPurifier/Strategy/MakeWellFormed.php new file mode 100644 index 000000000..c73658400 --- /dev/null +++ b/library/HTMLPurifier/Strategy/MakeWellFormed.php @@ -0,0 +1,475 @@ +<?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 |