Namespaces

Classes

Interfaces

Exceptions

Functions

1: <?php
2:
3: /**
4: * Takes tokens makes them well-formed (balance end tags, etc.)
5: *
6: * Specification of the armor attributes this strategy uses:
7: *
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].
13: */
14: class HTMLPurifier_Strategy_MakeWellFormed extends HTMLPurifier_Strategy
15: {
16:
17: /**
18: * Array stream of tokens being processed.
19: * @type HTMLPurifier_Token[]
20: */
21: protected $tokens;
22:
23: /**
24: * Current token.
25: * @type HTMLPurifier_Token
26: */
27: protected $token;
28:
29: /**
30: * Zipper managing the true state.
31: * @type HTMLPurifier_Zipper
32: */
33: protected $zipper;
34:
35: /**
36: * Current nesting of elements.
37: * @type array
38: */
39: protected $stack;
40:
41: /**
42: * Injectors active in this stream processing.
43: * @type HTMLPurifier_Injector[]
44: */
45: protected $injectors;
46:
47: /**
48: * Current instance of HTMLPurifier_Config.
49: * @type HTMLPurifier_Config
50: */
51: protected $config;
52:
53: /**
54: * Current instance of HTMLPurifier_Context.
55: * @type HTMLPurifier_Context
56: */
57: protected $context;
58:
59: /**
60: * @param HTMLPurifier_Token[] $tokens
61: * @param HTMLPurifier_Config $config
62: * @param HTMLPurifier_Context $context
63: * @return HTMLPurifier_Token[]
64: * @throws HTMLPurifier_Exception
65: */
66: public function execute($tokens, $config, $context)
67: {
68: $definition = $config->getHTMLDefinition();
69:
70: // local variables
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) {
79: return array();
80: }
81: $reprocess = false; // whether or not to reprocess the same token
82: $stack = array();
83:
84: // member variables
85: $this->stack =& $stack;
86: $this->tokens =& $tokens;
87: $this->token =& $token;
88: $this->zipper =& $zipper;
89: $this->config = $config;
90: $this->context = $context;
91:
92: // context variables
93: $context->register('CurrentNesting', $stack);
94: $context->register('InputZipper', $zipper);
95: $context->register('CurrentToken', $token);
96:
97: // -- begin INJECTOR --
98:
99: $this->injectors = array();
100:
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) {
108: continue;
109: }
110: $injector = "HTMLPurifier_Injector_$injector";
111: if (!$b) {
112: continue;
113: }
114: $this->injectors[] = new $injector;
115: }
116: foreach ($def_injectors as $injector) {
117: // assumed to be objects
118: $this->injectors[] = $injector;
119: }
120: foreach ($custom_injectors as $injector) {
121: if (!$injector) {
122: continue;
123: }
124: if (is_string($injector)) {
125: $injector = "HTMLPurifier_Injector_$injector";
126: $injector = new $injector;
127: }
128: $this->injectors[] = $injector;
129: }
130:
131: // give the injectors references to the definition and context
132: // variables for performance reasons
133: foreach ($this->injectors as $ix => $injector) {
134: $error = $injector->prepare($config, $context);
135: if (!$error) {
136: continue;
137: }
138: array_splice($this->injectors, $ix, 1); // rm the injector
139: trigger_error("Cannot enable {$injector->name} injector because $error is not allowed", E_USER_WARNING);
140: }
141:
142: // -- end INJECTOR --
143:
144: // a note on reprocessing:
145: // In order to reduce code duplication, whenever some code needs
146: // to make HTML changes in order to make things "correct", the
147: // new HTML gets sent through the purifier, regardless of its
148: // status. This means that if we add a start token, because it
149: // was totally necessary, we don't have to update nesting; we just
150: // punt ($reprocess = true; continue;) and it does that for us.
151:
152: // isset is in loop because $tokens size changes during loop exec
153: for (;;
154: // only increment if we don't need to reprocess
155: $reprocess ? $reprocess = false : $token = $zipper->next($token)) {
156:
157: // check for a rewind
158: if (is_int($i)) {
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. See Note [Injector skips]
169: unset($token->skip[$i]);
170: $token->rewind = $i;
171: if ($token instanceof HTMLPurifier_Token_Start) {
172: array_pop($this->stack);
173: } elseif ($token instanceof HTMLPurifier_Token_End) {
174: $this->stack[] = $token->start;
175: }
176: }
177: }
178: $i = false;
179: }
180:
181: // handle case of document end
182: if ($token === NULL) {
183: // kill processing if stack is empty
184: if (empty($this->stack)) {
185: break;
186: }
187:
188: // peek
189: $top_nesting = array_pop($this->stack);
190: $this->stack[] = $top_nesting;
191:
192: // send error [TagClosedSuppress]
193: if ($e && !isset($top_nesting->armor['MakeWellFormed_TagClosedError'])) {
194: $e->send(E_NOTICE, 'Strategy_MakeWellFormed: Tag closed by document end', $top_nesting);
195: }
196:
197: // append, don't splice, since this is the end
198: $token = new HTMLPurifier_Token_End($top_nesting->name);
199:
200: // punt!
201: $reprocess = true;
202: continue;
203: }
204:
205: //echo '<br>'; printZipper($zipper, $token);//printTokens($this->stack);
206: //flush();
207:
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[$i])) {
213: // See Note [Injector skips]
214: continue;
215: }
216: if ($token->rewind !== null && $token->rewind !== $i) {
217: continue;
218: }
219: // XXX fuckup
220: $r = $token;
221: $injector->handleText($r);
222: $token = $this->processToken($r, $i);
223: $reprocess = true;
224: break;
225: }
226: }
227: // another possibility is a comment
228: continue;
229: }
230:
231: if (isset($definition->info[$token->name])) {
232: $type = $definition->info[$token->name]->child->type;
233: } else {
234: $type = false; // Type is unknown, treat accordingly
235: }
236:
237: // quick tag checks: anything that's *not* an end tag
238: $ok = false;
239: if ($type === 'empty' && $token instanceof HTMLPurifier_Token_Start) {
240: // claims to be a start tag but is empty
241: $token = new HTMLPurifier_Token_Empty(
242: $token->name,
243: $token->attr,
244: $token->line,
245: $token->col,
246: $token->armor
247: );
248: $ok = true;
249: } elseif ($type && $type !== 'empty' && $token instanceof HTMLPurifier_Token_Empty) {
250: // claims to be empty but really is a start tag
251: // NB: this assignment is required
252: $old_token = $token;
253: $token = new HTMLPurifier_Token_End($token->name);
254: $token = $this->insertBefore(
255: new HTMLPurifier_Token_Start($old_token->name, $old_token->attr, $old_token->line, $old_token->col, $old_token->armor)
256: );
257: // punt (since we had to modify the input stream in a non-trivial way)
258: $reprocess = true;
259: continue;
260: } elseif ($token instanceof HTMLPurifier_Token_Empty) {
261: // real empty token
262: $ok = true;
263: } elseif ($token instanceof HTMLPurifier_Token_Start) {
264: // start tag
265:
266: // ...unless they also have to close their parent
267: if (!empty($this->stack)) {
268:
269: // Performance note: you might think that it's rather
270: // inefficient, recalculating the autoclose information
271: // for every tag that a token closes (since when we
272: // do an autoclose, we push a new token into the
273: // stream and then /process/ that, before
274: // re-processing this token.) But this is
275: // necessary, because an injector can make an
276: // arbitrary transformations to the autoclosing
277: // tokens we introduce, so things may have changed
278: // in the meantime. Also, doing the inefficient thing is
279: // "easy" to reason about (for certain perverse definitions
280: // of "easy")
281:
282: $parent = array_pop($this->stack);
283: $this->stack[] = $parent;
284:
285: $parent_def = null;
286: $parent_elements = null;
287: $autoclose = false;
288: if (isset($definition->info[$parent->name])) {
289: $parent_def = $definition->info[$parent->name];
290: $parent_elements = $parent_def->child->getAllowedElements($config);
291: $autoclose = !isset($parent_elements[$token->name]);
292: }
293:
294: if ($autoclose && $definition->info[$token->name]->wrap) {
295: // Check if an element can be wrapped by another
296: // element to make it valid in a context (for
297: // example, <ul><ul> needs a <li> in between)
298: $wrapname = $definition->info[$token->name]->wrap;
299: $wrapdef = $definition->info[$wrapname];
300: $elements = $wrapdef->child->getAllowedElements($config);
301: if (isset($elements[$token->name]) && isset($parent_elements[$wrapname])) {
302: $newtoken = new HTMLPurifier_Token_Start($wrapname);
303: $token = $this->insertBefore($newtoken);
304: $reprocess = true;
305: continue;
306: }
307: }
308:
309: $carryover = false;
310: if ($autoclose && $parent_def->formatting) {
311: $carryover = true;
312: }
313:
314: if ($autoclose) {
315: // check if this autoclose is doomed to fail
316: // (this rechecks $parent, which is harmless)
317: $autoclose_ok = isset($global_parent_allowed_elements[$token->name]);
318: if (!$autoclose_ok) {
319: foreach ($this->stack as $ancestor) {
320: $elements = $definition->info[$ancestor->name]->child->getAllowedElements($config);
321: if (isset($elements[$token->name])) {
322: $autoclose_ok = true;
323: break;
324: }
325: if ($definition->info[$token->name]->wrap) {
326: $wrapname = $definition->info[$token->name]->wrap;
327: $wrapdef = $definition->info[$wrapname];
328: $wrap_elements = $wrapdef->child->getAllowedElements($config);
329: if (isset($wrap_elements[$token->name]) && isset($elements[$wrapname])) {
330: $autoclose_ok = true;
331: break;
332: }
333: }
334: }
335: }
336: if ($autoclose_ok) {
337: // errors need to be updated
338: $new_token = new HTMLPurifier_Token_End($parent->name);
339: $new_token->start = $parent;
340: // [TagClosedSuppress]
341: if ($e && !isset($parent->armor['MakeWellFormed_TagClosedError'])) {
342: if (!$carryover) {
343: $e->send(E_NOTICE, 'Strategy_MakeWellFormed: Tag auto closed', $parent);
344: } else {
345: $e->send(E_NOTICE, 'Strategy_MakeWellFormed: Tag carryover', $parent);
346: }
347: }
348: if ($carryover) {
349: $element = clone $parent;
350: // [TagClosedAuto]
351: $element->armor['MakeWellFormed_TagClosedError'] = true;
352: $element->carryover = true;
353: $token = $this->processToken(array($new_token, $token, $element));
354: } else {
355: $token = $this->insertBefore($new_token);
356: }
357: } else {
358: $token = $this->remove();
359: }
360: $reprocess = true;
361: continue;
362: }
363:
364: }
365: $ok = true;
366: }
367:
368: if ($ok) {
369: foreach ($this->injectors as $i => $injector) {
370: if (isset($token->skip[$i])) {
371: // See Note [Injector skips]
372: continue;
373: }
374: if ($token->rewind !== null && $token->rewind !== $i) {
375: continue;
376: }
377: $r = $token;
378: $injector->handleElement($r);
379: $token = $this->processToken($r, $i);
380: $reprocess = true;
381: break;
382: }
383: if (!$reprocess) {
384: // ah, nothing interesting happened; do normal processing
385: if ($token instanceof HTMLPurifier_Token_Start) {
386: $this->stack[] = $token;
387: } elseif ($token instanceof HTMLPurifier_Token_End) {
388: throw new HTMLPurifier_Exception(
389: 'Improper handling of end tag in start code; possible error in MakeWellFormed'
390: );
391: }
392: }
393: continue;
394: }
395:
396: // sanity check: we should be dealing with a closing tag
397: if (!$token instanceof HTMLPurifier_Token_End) {
398: throw new HTMLPurifier_Exception('Unaccounted for tag token in input stream, bug in HTML Purifier');
399: }
400:
401: // make sure that we have something open
402: if (empty($this->stack)) {
403: if ($escape_invalid_tags) {
404: if ($e) {
405: $e->send(E_WARNING, 'Strategy_MakeWellFormed: Unnecessary end tag to text');
406: }
407: $token = new HTMLPurifier_Token_Text($generator->generateFromToken($token));
408: } else {
409: if ($e) {
410: $e->send(E_WARNING, 'Strategy_MakeWellFormed: Unnecessary end tag removed');
411: }
412: $token = $this->remove();
413: }
414: $reprocess = true;
415: continue;
416: }
417:
418: // first, check for the simplest case: everything closes neatly.
419: // Eventually, everything passes through here; if there are problems
420: // we modify the input stream accordingly and then punt, so that
421: // the tokens get processed again.
422: $current_parent = array_pop($this->stack);
423: if ($current_parent->name == $token->name) {
424: $token->start = $current_parent;
425: foreach ($this->injectors as $i => $injector) {
426: if (isset($token->skip[$i])) {
427: // See Note [Injector skips]
428: continue;
429: }
430: if ($token->rewind !== null && $token->rewind !== $i) {
431: continue;
432: }
433: $r = $token;
434: $injector->handleEnd($r);
435: $token = $this->processToken($r, $i);
436: $this->stack[] = $current_parent;
437: $reprocess = true;
438: break;
439: }
440: continue;
441: }
442:
443: // okay, so we're trying to close the wrong tag
444:
445: // undo the pop previous pop
446: $this->stack[] = $current_parent;
447:
448: // scroll back the entire nest, trying to find our tag.
449: // (feature could be to specify how far you'd like to go)
450: $size = count($this->stack);
451: // -2 because -1 is the last element, but we already checked that
452: $skipped_tags = false;
453: for ($j = $size - 2; $j >= 0; $j--) {
454: if ($this->stack[$j]->name == $token->name) {
455: $skipped_tags = array_slice($this->stack, $j);
456: break;
457: }
458: }
459:
460: // we didn't find the tag, so remove
461: if ($skipped_tags === false) {
462: if ($escape_invalid_tags) {
463: if ($e) {
464: $e->send(E_WARNING, 'Strategy_MakeWellFormed: Stray end tag to text');
465: }
466: $token = new HTMLPurifier_Token_Text($generator->generateFromToken($token));
467: } else {
468: if ($e) {
469: $e->send(E_WARNING, 'Strategy_MakeWellFormed: Stray end tag removed');
470: }
471: $token = $this->remove();
472: }
473: $reprocess = true;
474: continue;
475: }
476:
477: // do errors, in REVERSE $j order: a,b,c with </a></b></c>
478: $c = count($skipped_tags);
479: if ($e) {
480: for ($j = $c - 1; $j > 0; $j--) {
481: // notice we exclude $j == 0, i.e. the current ending tag, from
482: // the errors... [TagClosedSuppress]
483: if (!isset($skipped_tags[$j]->armor['MakeWellFormed_TagClosedError'])) {
484: $e->send(E_NOTICE, 'Strategy_MakeWellFormed: Tag closed by element end', $skipped_tags[$j]);
485: }
486: }
487: }
488:
489: // insert tags, in FORWARD $j order: c,b,a with </a></b></c>
490: $replace = array($token);
491: for ($j = 1; $j < $c; $j++) {
492: // ...as well as from the insertions
493: $new_token = new HTMLPurifier_Token_End($skipped_tags[$j]->name);
494: $new_token->start = $skipped_tags[$j];
495: array_unshift($replace, $new_token);
496: if (isset($definition->info[$new_token->name]) && $definition->info[$new_token->name]->formatting) {
497: // [TagClosedAuto]
498: $element = clone $skipped_tags[$j];
499: $element->carryover = true;
500: $element->armor['MakeWellFormed_TagClosedError'] = true;
501: $replace[] = $element;
502: }
503: }
504: $token = $this->processToken($replace);
505: $reprocess = true;
506: continue;
507: }
508:
509: $context->destroy('CurrentToken');
510: $context->destroy('CurrentNesting');
511: $context->destroy('InputZipper');
512:
513: unset($this->injectors, $this->stack, $this->tokens);
514: return $zipper->toArray($token);
515: }
516:
517: /**
518: * Processes arbitrary token values for complicated substitution patterns.
519: * In general:
520: *
521: * If $token is an array, it is a list of tokens to substitute for the
522: * current token. These tokens then get individually processed. If there
523: * is a leading integer in the list, that integer determines how many
524: * tokens from the stream should be removed.
525: *
526: * If $token is a regular token, it is swapped with the current token.
527: *
528: * If $token is false, the current token is deleted.
529: *
530: * If $token is an integer, that number of tokens (with the first token
531: * being the current one) will be deleted.
532: *
533: * @param HTMLPurifier_Token|array|int|bool $token Token substitution value
534: * @param HTMLPurifier_Injector|int $injector Injector that performed the substitution; default is if
535: * this is not an injector related operation.
536: * @throws HTMLPurifier_Exception
537: */
538: protected function processToken($token, $injector = -1)
539: {
540: // Zend OpCache miscompiles $token = array($token), so
541: // avoid this pattern. See: https://github.com/ezyang/htmlpurifier/issues/108
542:
543: // normalize forms of token
544: if (is_object($token)) {
545: $tmp = $token;
546: $token = array(1, $tmp);
547: }
548: if (is_int($token)) {
549: $tmp = $token;
550: $token = array($tmp);
551: }
552: if ($token === false) {
553: $token = array(1);
554: }
555: if (!is_array($token)) {
556: throw new HTMLPurifier_Exception('Invalid token type from injector');
557: }
558: if (!is_int($token[0])) {
559: array_unshift($token, 1);
560: }
561: if ($token[0] === 0) {
562: throw new HTMLPurifier_Exception('Deleting zero tokens is not valid');
563: }
564:
565: // $token is now an array with the following form:
566: // array(number nodes to delete, new node 1, new node 2, ...)
567:
568: $delete = array_shift($token);
569: list($old, $r) = $this->zipper->splice($this->token, $delete, $token);
570:
571: if ($injector > -1) {
572: // See Note [Injector skips]
573: // Determine appropriate skips. Here's what the code does:
574: // *If* we deleted one or more tokens, copy the skips
575: // of those tokens into the skips of the new tokens (in $token).
576: // Also, mark the newly inserted tokens as having come from
577: // $injector.
578: $oldskip = isset($old[0]) ? $old[0]->skip : array();
579: foreach ($token as $object) {
580: $object->skip = $oldskip;
581: $object->skip[$injector] = true;
582: }
583: }
584:
585: return $r;
586:
587: }
588:
589: /**
590: * Inserts a token before the current token. Cursor now points to
591: * this token. You must reprocess after this.
592: * @param HTMLPurifier_Token $token
593: */
594: private function insertBefore($token)
595: {
596: // NB not $this->zipper->insertBefore(), due to positioning
597: // differences
598: $splice = $this->zipper->splice($this->token, 0, array($token));
599:
600: return $splice[1];
601: }
602:
603: /**
604: * Removes current token. Cursor now points to new token occupying previously
605: * occupied space. You must reprocess after this.
606: */
607: private function remove()
608: {
609: return $this->zipper->delete();
610: }
611: }
612:
613: // Note [Injector skips]
614: // ~~~~~~~~~~~~~~~~~~~~~
615: // When I originally designed this class, the idea behind the 'skip'
616: // property of HTMLPurifier_Token was to help avoid infinite loops
617: // in injector processing. For example, suppose you wrote an injector
618: // that bolded swear words. Naively, you might write it so that
619: // whenever you saw ****, you replaced it with <strong>****</strong>.
620: //
621: // When this happens, we will reprocess all of the tokens with the
622: // other injectors. Now there is an opportunity for infinite loop:
623: // if we rerun the swear-word injector on these tokens, we might
624: // see **** and then reprocess again to get
625: // <strong><strong>****</strong></strong> ad infinitum.
626: //
627: // Thus, the idea of a skip is that once we process a token with
628: // an injector, we mark all of those tokens as having "come from"
629: // the injector, and we never run the injector again on these
630: // tokens.
631: //
632: // There were two more complications, however:
633: //
634: // - With HTMLPurifier_Injector_RemoveEmpty, we noticed that if
635: // you had <b><i></i></b>, after you removed the <i></i>, you
636: // really would like this injector to go back and reprocess
637: // the <b> tag, discovering that it is now empty and can be
638: // removed. So we reintroduced the possibility of infinite looping
639: // by adding a "rewind" function, which let you go back to an
640: // earlier point in the token stream and reprocess it with injectors.
641: // Needless to say, we need to UN-skip the token so it gets
642: // reprocessed.
643: //
644: // - Suppose that you successfuly process a token, replace it with
645: // one with your skip mark, but now another injector wants to
646: // process the skipped token with another token. Should you continue
647: // to skip that new token, or reprocess it? If you reprocess,
648: // you can end up with an infinite loop where one injector converts
649: // <a> to <b>, and then another injector converts it back. So
650: // we inherit the skips, but for some reason, I thought that we
651: // should inherit the skip from the first token of the token
652: // that we deleted. Why? Well, it seems to work OK.
653: //
654: // If I were to redesign this functionality, I would absolutely not
655: // go about doing it this way: the semantics are just not very well
656: // defined, and in any case you probably wanted to operate on trees,
657: // not token streams.
658:
659: // vim: et sw=4 sts=4
660:
API documentation generated by ApiGen v7.0.0-alpha.6