4 * Takes tokens makes them well-formed (balance end tags, etc.)
6 * Specification of the armor attributes this strategy uses:
8 * - MakeWellFormed_TagClosedError: This armor field is used to
9 * suppress tag closed errors for certain tokens [TagClosedSuppress],
10 * in particular, if a tag was generated automatically by HTML
11 * Purifier, we may rely on our infrastructure to close it for us
12 * and shouldn't report an error to the user [TagClosedAuto].
14 class HTMLPurifier_Strategy_MakeWellFormed extends HTMLPurifier_Strategy
18 * Array stream of tokens being processed.
19 * @type HTMLPurifier_Token[]
25 * @type HTMLPurifier_Token
30 * Zipper managing the true state.
31 * @type HTMLPurifier_Zipper
36 * Current nesting of elements.
42 * Injectors active in this stream processing.
43 * @type HTMLPurifier_Injector[]
48 * Current instance of HTMLPurifier_Config.
49 * @type HTMLPurifier_Config
54 * Current instance of HTMLPurifier_Context.
55 * @type HTMLPurifier_Context
60 * @param HTMLPurifier_Token[] $tokens
61 * @param HTMLPurifier_Config $config
62 * @param HTMLPurifier_Context $context
63 * @return HTMLPurifier_Token[]
64 * @throws HTMLPurifier_Exception
66 public function execute($tokens, $config, $context)
68 $definition = $config->getHTMLDefinition();
71 $generator = new HTMLPurifier_Generator($config, $context);
72 $escape_invalid_tags = $config->get('Core.EscapeInvalidTags');
73 // used for autoclose early abortion
74 $global_parent_allowed_elements = $definition->info_parent_def->child->getAllowedElements($config);
75 $e = $context->get('ErrorCollector', true);
76 $i = false; // injector index
77 list($zipper, $token) = HTMLPurifier_Zipper::fromArray($tokens);
78 if ($token === NULL) {
81 $reprocess = false; // whether or not to reprocess the same token
85 $this->stack =& $stack;
86 $this->tokens =& $tokens;
87 $this->token =& $token;
88 $this->zipper =& $zipper;
89 $this->config = $config;
90 $this->context = $context;
93 $context->register('CurrentNesting', $stack);
94 $context->register('InputZipper', $zipper);
95 $context->register('CurrentToken', $token);
97 // -- begin INJECTOR --
99 $this->injectors = array();
101 $injectors = $config->getBatch('AutoFormat');
102 $def_injectors = $definition->info_injector;
103 $custom_injectors = $injectors['Custom'];
104 unset($injectors['Custom']); // special case
105 foreach ($injectors as $injector => $b) {
106 // XXX: Fix with a legitimate lookup table of enabled filters
107 if (strpos($injector, '.') !== false) {
110 $injector = "HTMLPurifier_Injector_$injector";
114 $this->injectors[] = new $injector;
116 foreach ($def_injectors as $injector) {
117 // assumed to be objects
118 $this->injectors[] = $injector;
120 foreach ($custom_injectors as $injector) {
124 if (is_string($injector)) {
125 $injector = "HTMLPurifier_Injector_$injector";
126 $injector = new $injector;
128 $this->injectors[] = $injector;
131 // give the injectors references to the definition and context
132 // variables for performance reasons
133 foreach ($this->injectors as $ix => $injector) {
134 $error = $injector->prepare($config, $context);
138 array_splice($this->injectors, $ix, 1); // rm the injector
139 trigger_error("Cannot enable {$injector->name} injector because $error is not allowed", E_USER_WARNING);
142 // -- end INJECTOR --
144 // a note on reprocessing:
145 // In order to reduce code duplication, whenever some code needs
146 // to make HTML changes in order to make things "correct", the
147 // new HTML gets sent through the purifier, regardless of its
148 // status. This means that if we add a start token, because it
149 // was totally necessary, we don't have to update nesting; we just
150 // punt ($reprocess = true; continue;) and it does that for us.
152 // isset is in loop because $tokens size changes during loop exec
154 // only increment if we don't need to reprocess
155 $reprocess ? $reprocess = false : $token = $zipper->next($token)) {
157 // check for a rewind
159 // possibility: disable rewinding if the current token has a
160 // rewind set on it already. This would offer protection from
161 // infinite loop, but might hinder some advanced rewinding.
162 $rewind_offset = $this->injectors[$i]->getRewindOffset();
163 if (is_int($rewind_offset)) {
164 for ($j = 0; $j < $rewind_offset; $j++) {
165 if (empty($zipper->front)) break;
166 $token = $zipper->prev($token);
167 // indicate that other injectors should not process this token,
168 // but we need to reprocess it
169 unset($token->skip[$i]);
171 if ($token instanceof HTMLPurifier_Token_Start) {
172 array_pop($this->stack);
173 } elseif ($token instanceof HTMLPurifier_Token_End) {
174 $this->stack[] = $token->start;
181 // handle case of document end
182 if ($token === NULL) {
183 // kill processing if stack is empty
184 if (empty($this->stack)) {
189 $top_nesting = array_pop($this->stack);
190 $this->stack[] = $top_nesting;
192 // send error [TagClosedSuppress]
193 if ($e && !isset($top_nesting->armor['MakeWellFormed_TagClosedError'])) {
194 $e->send(E_NOTICE, 'Strategy_MakeWellFormed: Tag closed by document end', $top_nesting);
197 // append, don't splice, since this is the end
198 $token = new HTMLPurifier_Token_End($top_nesting->name);
205 //echo '<br>'; printZipper($zipper, $token);//printTokens($this->stack);
208 // quick-check: if it's not a tag, no need to process
209 if (empty($token->is_tag)) {
210 if ($token instanceof HTMLPurifier_Token_Text) {
211 foreach ($this->injectors as $i => $injector) {
212 if (isset($token->skip[$i])) {
215 if ($token->rewind !== null && $token->rewind !== $i) {
220 $injector->handleText($r);
221 $token = $this->processToken($r, $i);
226 // another possibility is a comment
230 if (isset($definition->info[$token->name])) {
231 $type = $definition->info[$token->name]->child->type;
233 $type = false; // Type is unknown, treat accordingly
236 // quick tag checks: anything that's *not* an end tag
238 if ($type === 'empty' && $token instanceof HTMLPurifier_Token_Start) {
239 // claims to be a start tag but is empty
240 $token = new HTMLPurifier_Token_Empty(
248 } elseif ($type && $type !== 'empty' && $token instanceof HTMLPurifier_Token_Empty) {
249 // claims to be empty but really is a start tag
250 // NB: this assignment is required
252 $token = new HTMLPurifier_Token_End($token->name);
253 $token = $this->insertBefore(
254 new HTMLPurifier_Token_Start($old_token->name, $old_token->attr, $old_token->line, $old_token->col, $old_token->armor)
256 // punt (since we had to modify the input stream in a non-trivial way)
259 } elseif ($token instanceof HTMLPurifier_Token_Empty) {
262 } elseif ($token instanceof HTMLPurifier_Token_Start) {
265 // ...unless they also have to close their parent
266 if (!empty($this->stack)) {
268 // Performance note: you might think that it's rather
269 // inefficient, recalculating the autoclose information
270 // for every tag that a token closes (since when we
271 // do an autoclose, we push a new token into the
272 // stream and then /process/ that, before
273 // re-processing this token.) But this is
274 // necessary, because an injector can make an
275 // arbitrary transformations to the autoclosing
276 // tokens we introduce, so things may have changed
277 // in the meantime. Also, doing the inefficient thing is
278 // "easy" to reason about (for certain perverse definitions
281 $parent = array_pop($this->stack);
282 $this->stack[] = $parent;
285 $parent_elements = null;
287 if (isset($definition->info[$parent->name])) {
288 $parent_def = $definition->info[$parent->name];
289 $parent_elements = $parent_def->child->getAllowedElements($config);
290 $autoclose = !isset($parent_elements[$token->name]);
293 if ($autoclose && $definition->info[$token->name]->wrap) {
294 // Check if an element can be wrapped by another
295 // element to make it valid in a context (for
296 // example, <ul><ul> needs a <li> in between)
297 $wrapname = $definition->info[$token->name]->wrap;
298 $wrapdef = $definition->info[$wrapname];
299 $elements = $wrapdef->child->getAllowedElements($config);
300 if (isset($elements[$token->name]) && isset($parent_elements[$wrapname])) {
301 $newtoken = new HTMLPurifier_Token_Start($wrapname);
302 $token = $this->insertBefore($newtoken);
309 if ($autoclose && $parent_def->formatting) {
314 // check if this autoclose is doomed to fail
315 // (this rechecks $parent, which his harmless)
316 $autoclose_ok = isset($global_parent_allowed_elements[$token->name]);
317 if (!$autoclose_ok) {
318 foreach ($this->stack as $ancestor) {
319 $elements = $definition->info[$ancestor->name]->child->getAllowedElements($config);
320 if (isset($elements[$token->name])) {
321 $autoclose_ok = true;
324 if ($definition->info[$token->name]->wrap) {
325 $wrapname = $definition->info[$token->name]->wrap;
326 $wrapdef = $definition->info[$wrapname];
327 $wrap_elements = $wrapdef->child->getAllowedElements($config);
328 if (isset($wrap_elements[$token->name]) && isset($elements[$wrapname])) {
329 $autoclose_ok = true;
336 // errors need to be updated
337 $new_token = new HTMLPurifier_Token_End($parent->name);
338 $new_token->start = $parent;
339 // [TagClosedSuppress]
340 if ($e && !isset($parent->armor['MakeWellFormed_TagClosedError'])) {
342 $e->send(E_NOTICE, 'Strategy_MakeWellFormed: Tag auto closed', $parent);
344 $e->send(E_NOTICE, 'Strategy_MakeWellFormed: Tag carryover', $parent);
348 $element = clone $parent;
350 $element->armor['MakeWellFormed_TagClosedError'] = true;
351 $element->carryover = true;
352 $token = $this->processToken(array($new_token, $token, $element));
354 $token = $this->insertBefore($new_token);
357 $token = $this->remove();
368 foreach ($this->injectors as $i => $injector) {
369 if (isset($token->skip[$i])) {
372 if ($token->rewind !== null && $token->rewind !== $i) {
376 $injector->handleElement($r);
377 $token = $this->processToken($r, $i);
382 // ah, nothing interesting happened; do normal processing
383 if ($token instanceof HTMLPurifier_Token_Start) {
384 $this->stack[] = $token;
385 } elseif ($token instanceof HTMLPurifier_Token_End) {
386 throw new HTMLPurifier_Exception(
387 'Improper handling of end tag in start code; possible error in MakeWellFormed'
394 // sanity check: we should be dealing with a closing tag
395 if (!$token instanceof HTMLPurifier_Token_End) {
396 throw new HTMLPurifier_Exception('Unaccounted for tag token in input stream, bug in HTML Purifier');
399 // make sure that we have something open
400 if (empty($this->stack)) {
401 if ($escape_invalid_tags) {
403 $e->send(E_WARNING, 'Strategy_MakeWellFormed: Unnecessary end tag to text');
405 $token = new HTMLPurifier_Token_Text($generator->generateFromToken($token));
408 $e->send(E_WARNING, 'Strategy_MakeWellFormed: Unnecessary end tag removed');
410 $token = $this->remove();
416 // first, check for the simplest case: everything closes neatly.
417 // Eventually, everything passes through here; if there are problems
418 // we modify the input stream accordingly and then punt, so that
419 // the tokens get processed again.
420 $current_parent = array_pop($this->stack);
421 if ($current_parent->name == $token->name) {
422 $token->start = $current_parent;
423 foreach ($this->injectors as $i => $injector) {
424 if (isset($token->skip[$i])) {
427 if ($token->rewind !== null && $token->rewind !== $i) {
431 $injector->handleEnd($r);
432 $token = $this->processToken($r, $i);
433 $this->stack[] = $current_parent;
440 // okay, so we're trying to close the wrong tag
442 // undo the pop previous pop
443 $this->stack[] = $current_parent;
445 // scroll back the entire nest, trying to find our tag.
446 // (feature could be to specify how far you'd like to go)
447 $size = count($this->stack);
448 // -2 because -1 is the last element, but we already checked that
449 $skipped_tags = false;
450 for ($j = $size - 2; $j >= 0; $j--) {
451 if ($this->stack[$j]->name == $token->name) {
452 $skipped_tags = array_slice($this->stack, $j);
457 // we didn't find the tag, so remove
458 if ($skipped_tags === false) {
459 if ($escape_invalid_tags) {
461 $e->send(E_WARNING, 'Strategy_MakeWellFormed: Stray end tag to text');
463 $token = new HTMLPurifier_Token_Text($generator->generateFromToken($token));
466 $e->send(E_WARNING, 'Strategy_MakeWellFormed: Stray end tag removed');
468 $token = $this->remove();
474 // do errors, in REVERSE $j order: a,b,c with </a></b></c>
475 $c = count($skipped_tags);
477 for ($j = $c - 1; $j > 0; $j--) {
478 // notice we exclude $j == 0, i.e. the current ending tag, from
479 // the errors... [TagClosedSuppress]
480 if (!isset($skipped_tags[$j]->armor['MakeWellFormed_TagClosedError'])) {
481 $e->send(E_NOTICE, 'Strategy_MakeWellFormed: Tag closed by element end', $skipped_tags[$j]);
486 // insert tags, in FORWARD $j order: c,b,a with </a></b></c>
487 $replace = array($token);
488 for ($j = 1; $j < $c; $j++) {
489 // ...as well as from the insertions
490 $new_token = new HTMLPurifier_Token_End($skipped_tags[$j]->name);
491 $new_token->start = $skipped_tags[$j];
492 array_unshift($replace, $new_token);
493 if (isset($definition->info[$new_token->name]) && $definition->info[$new_token->name]->formatting) {
495 $element = clone $skipped_tags[$j];
496 $element->carryover = true;
497 $element->armor['MakeWellFormed_TagClosedError'] = true;
498 $replace[] = $element;
501 $token = $this->processToken($replace);
506 $context->destroy('CurrentToken');
507 $context->destroy('CurrentNesting');
508 $context->destroy('InputZipper');
510 unset($this->injectors, $this->stack, $this->tokens);
511 return $zipper->toArray($token);
515 * Processes arbitrary token values for complicated substitution patterns.
518 * If $token is an array, it is a list of tokens to substitute for the
519 * current token. These tokens then get individually processed. If there
520 * is a leading integer in the list, that integer determines how many
521 * tokens from the stream should be removed.
523 * If $token is a regular token, it is swapped with the current token.
525 * If $token is false, the current token is deleted.
527 * If $token is an integer, that number of tokens (with the first token
528 * being the current one) will be deleted.
530 * @param HTMLPurifier_Token|array|int|bool $token Token substitution value
531 * @param HTMLPurifier_Injector|int $injector Injector that performed the substitution; default is if
532 * this is not an injector related operation.
533 * @throws HTMLPurifier_Exception
535 protected function processToken($token, $injector = -1)
537 // normalize forms of token
538 if (is_object($token)) {
539 $token = array(1, $token);
541 if (is_int($token)) {
542 $token = array($token);
544 if ($token === false) {
547 if (!is_array($token)) {
548 throw new HTMLPurifier_Exception('Invalid token type from injector');
550 if (!is_int($token[0])) {
551 array_unshift($token, 1);
553 if ($token[0] === 0) {
554 throw new HTMLPurifier_Exception('Deleting zero tokens is not valid');
557 // $token is now an array with the following form:
558 // array(number nodes to delete, new node 1, new node 2, ...)
560 $delete = array_shift($token);
561 list($old, $r) = $this->zipper->splice($this->token, $delete, $token);
563 if ($injector > -1) {
564 // determine appropriate skips
565 $oldskip = isset($old[0]) ? $old[0]->skip : array();
566 foreach ($token as $object) {
567 $object->skip = $oldskip;
568 $object->skip[$injector] = true;
577 * Inserts a token before the current token. Cursor now points to
578 * this token. You must reprocess after this.
579 * @param HTMLPurifier_Token $token
581 private function insertBefore($token)
583 // NB not $this->zipper->insertBefore(), due to positioning
585 $splice = $this->zipper->splice($this->token, 0, array($token));
591 * Removes current token. Cursor now points to new token occupying previously
592 * occupied space. You must reprocess after this.
594 private function remove()
596 return $this->zipper->delete();
600 // vim: et sw=4 sts=4