includes/tidy/RemexCompatMunger.php

   1 <?php
   2
   3 namespace MediaWiki\Tidy;
   4
   5 use RemexHtml\HTMLData;
   6 use RemexHtml\Serializer\Serializer;
   7 use RemexHtml\Serializer\SerializerNode;
   8 use RemexHtml\Tokenizer\Attributes;
   9 use RemexHtml\Tokenizer\PlainAttributes;
  10 use RemexHtml\TreeBuilder\TreeBuilder;
  11 use RemexHtml\TreeBuilder\TreeHandler;
  12 use RemexHtml\TreeBuilder\Element;
  13
  14 /**
  15  * @internal
  16  */
  17 class RemexCompatMunger implements TreeHandler {
  18         private static $onlyInlineElements = [
  19                 "a" => true,
  20                 "abbr" => true,
  21                 "acronym" => true,
  22                 "applet" => true,
  23                 "b" => true,
  24                 "basefont" => true,
  25                 "bdo" => true,
  26                 "big" => true,
  27                 "br" => true,
  28                 "button" => true,
  29                 "cite" => true,
  30                 "code" => true,
  31                 "del" => true,
  32                 "dfn" => true,
  33                 "em" => true,
  34                 "font" => true,
  35                 "i" => true,
  36                 "iframe" => true,
  37                 "img" => true,
  38                 "input" => true,
  39                 "ins" => true,
  40                 "kbd" => true,
  41                 "label" => true,
  42                 "legend" => true,
  43                 "map" => true,
  44                 "object" => true,
  45                 "param" => true,
  46                 "q" => true,
  47                 "rb" => true,
  48                 "rbc" => true,
  49                 "rp" => true,
  50                 "rt" => true,
  51                 "rtc" => true,
  52                 "ruby" => true,
  53                 "s" => true,
  54                 "samp" => true,
  55                 "select" => true,
  56                 "small" => true,
  57                 "span" => true,
  58                 "strike" => true,
  59                 "strong" => true,
  60                 "sub" => true,
  61                 "sup" => true,
  62                 "textarea" => true,
  63                 "tt" => true,
  64                 "u" => true,
  65                 "var" => true,
  66                 // Those defined in tidy.conf
  67                 "video" => true,
  68                 "audio" => true,
  69                 "bdi" => true,
  70                 "data" => true,
  71                 "time" => true,
  72                 "mark" => true,
  73         ];
  74
  75         /**
  76          * For the purposes of this class, "metadata" elements are those that
  77          * should neither trigger p-wrapping nor stop an outer p-wrapping,
  78          * typically those that are themselves invisible in a browser's rendering.
  79          * This isn't a complete list, it's just the tags that we're likely to
  80          * encounter in practice.
  81          * @var array
  82          */
  83         private static $metadataElements = [
  84                 'style' => true,
  85                 'script' => true,
  86                 'link' => true,
  87                 'meta' => true,
  88         ];
  89
  90         private static $formattingElements = [
  91                 'a' => true,
  92                 'b' => true,
  93                 'big' => true,
  94                 'code' => true,
  95                 'em' => true,
  96                 'font' => true,
  97                 'i' => true,
  98                 'nobr' => true,
  99                 's' => true,
 100                 'small' => true,
 101                 'strike' => true,
 102                 'strong' => true,
 103                 'tt' => true,
 104                 'u' => true,
 105         ];
 106
 107         /** @var Serializer */
 108         private $serializer;
 109
 110         /** @var bool */
 111         private $trace;
 112
 113         /**
 114          * @param Serializer $serializer
 115          * @param bool $trace
 116          */
 117         public function __construct( Serializer $serializer, $trace = false ) {
 118                 $this->serializer = $serializer;
 119                 $this->trace = $trace;
 120         }
 121
 122         public function startDocument( $fragmentNamespace, $fragmentName ) {
 123                 $this->serializer->startDocument( $fragmentNamespace, $fragmentName );
 124                 $root = $this->serializer->getRootNode();
 125                 $root->snData = new RemexMungerData;
 126                 $root->snData->needsPWrapping = true;
 127         }
 128
 129         public function endDocument( $pos ) {
 130                 $this->serializer->endDocument( $pos );
 131         }
 132
 133         private function getParentForInsert( $preposition, $refElement ) {
 134                 if ( $preposition === TreeBuilder::ROOT ) {
 135                         return [ $this->serializer->getRootNode(), null ];
 136                 } elseif ( $preposition === TreeBuilder::BEFORE ) {
 137                         $refNode = $refElement->userData;
 138                         return [ $this->serializer->getParentNode( $refNode ), $refNode ];
 139                 } else {
 140                         $refNode = $refElement->userData;
 141                         $refData = $refNode->snData;
 142                         if ( $refData->currentCloneElement ) {
 143                                 // Follow a chain of clone links if necessary
 144                                 $origRefData = $refData;
 145                                 while ( $refData->currentCloneElement ) {
 146                                         $refElement = $refData->currentCloneElement;
 147                                         $refNode = $refElement->userData;
 148                                         $refData = $refNode->snData;
 149                                 }
 150                                 // Cache the end of the chain in the requested element
 151                                 $origRefData->currentCloneElement = $refElement;
 152                         } elseif ( $refData->childPElement ) {
 153                                 $refElement = $refData->childPElement;
 154                                 $refNode = $refElement->userData;
 155                         }
 156                         return [ $refNode, $refNode ];
 157                 }
 158         }
 159
 160         /**
 161          * Insert a p-wrapper
 162          *
 163          * @param SerializerNode $parent
 164          * @param int $sourceStart
 165          * @return SerializerNode
 166          */
 167         private function insertPWrapper( SerializerNode $parent, $sourceStart ) {
 168                 $pWrap = new Element( HTMLData::NS_HTML, 'mw:p-wrap', new PlainAttributes );
 169                 $this->serializer->insertElement( TreeBuilder::UNDER, $parent, $pWrap, false,
 170                         $sourceStart, 0 );
 171                 $data = new RemexMungerData;
 172                 $data->isPWrapper = true;
 173                 $data->wrapBaseNode = $parent;
 174                 $pWrap->userData->snData = $data;
 175                 $parent->snData->childPElement = $pWrap;
 176                 return $pWrap->userData;
 177         }
 178
 179         public function characters( $preposition, $refElement, $text, $start, $length,
 180                 $sourceStart, $sourceLength
 181         ) {
 182                 $isBlank = strspn( $text, "\t\n\f\r ", $start, $length ) === $length;
 183
 184                 list( $parent, $refNode ) = $this->getParentForInsert( $preposition, $refElement );
 185                 $parentData = $parent->snData;
 186
 187                 if ( $preposition === TreeBuilder::UNDER ) {
 188                         if ( $parentData->needsPWrapping && !$isBlank ) {
 189                                 // Add a p-wrapper for bare text under body/blockquote
 190                                 $refNode = $this->insertPWrapper( $refNode, $sourceStart );
 191                                 $parent = $refNode;
 192                                 $parentData = $parent->snData;
 193                         } elseif ( $parentData->isSplittable && !$parentData->ancestorPNode ) {
 194                                 // The parent is splittable and in block mode, so split the tag stack
 195                                 $refNode = $this->splitTagStack( $refNode, true, $sourceStart );
 196                                 $parent = $refNode;
 197                                 $parentData = $parent->snData;
 198                         }
 199                 }
 200
 201                 if ( !$isBlank ) {
 202                         // Non-whitespace characters detected
 203                         $parentData->nonblankNodeCount++;
 204                 }
 205                 $this->serializer->characters( $preposition, $refNode, $text, $start,
 206                         $length, $sourceStart, $sourceLength );
 207         }
 208
 209         private function trace( $msg ) {
 210                 if ( $this->trace ) {
 211                         wfDebug( "[RCM] $msg" );
 212                 }
 213         }
 214
 215         /**
 216          * Insert or reparent an element. Create p-wrappers or split the tag stack
 217          * as necessary.
 218          *
 219          * Consider the following insertion locations. The parent may be:
 220          *
 221          *   - A: A body or blockquote (!!needsPWrapping)
 222          *   - B: A p-wrapper (!!isPWrapper)
 223          *   - C: A descendant of a p-wrapper (!!ancestorPNode)
 224          *     - CS: With splittable formatting elements in the stack region up to
 225          *       the p-wrapper
 226          *     - CU: With one or more unsplittable elements in the stack region up
 227          *       to the p-wrapper
 228          *   - D: Not a descendant of a p-wrapper (!ancestorNode)
 229          *     - DS: With splittable formatting elements in the stack region up to
 230          *       the body or blockquote
 231          *     - DU: With one or more unsplittable elements in the stack region up
 232          *       to the body or blockquote
 233          *
 234          * And consider that we may insert two types of element:
 235          *   - b: block
 236          *   - i: inline
 237          *
 238          * We handle the insertion as follows:
 239          *
 240          *   - A/i: Create a p-wrapper, insert under it
 241          *   - A/b: Insert as normal
 242          *   - B/i: Insert as normal
 243          *   - B/b: Close the p-wrapper, insert under the body/blockquote (wrap
 244          *     base) instead)
 245          *   - C/i: Insert as normal
 246          *   - CS/b: Split the tag stack, insert the block under cloned formatting
 247          *     elements which have the wrap base (the parent of the p-wrap) as
 248          *     their ultimate parent.
 249          *   - CU/b: Disable the p-wrap, by reparenting the currently open child
 250          *     of the p-wrap under the p-wrap's parent. Then insert the block as
 251          *     normal.
 252          *   - D/b: Insert as normal
 253          *   - DS/i: Split the tag stack, creating a new p-wrapper as the ultimate
 254          *     parent of the formatting elements thus cloned. The parent of the
 255          *     p-wrapper is the body or blockquote.
 256          *   - DU/i: Insert as normal
 257          *
 258          * FIXME: fostering ($preposition == BEFORE) is mostly done by inserting as
 259          * normal, the full algorithm is not followed.
 260          *
 261          * @param int $preposition
 262          * @param Element|SerializerNode|null $refElement
 263          * @param Element $element
 264          * @param bool $void
 265          * @param int $sourceStart
 266          * @param int $sourceLength
 267          */
 268         public function insertElement( $preposition, $refElement, Element $element, $void,
 269                 $sourceStart, $sourceLength
 270         ) {
 271                 list( $parent, $newRef ) = $this->getParentForInsert( $preposition, $refElement );
 272                 $parentData = $parent->snData;
 273                 $elementName = $element->htmlName;
 274
 275                 $inline = isset( self::$onlyInlineElements[$elementName] );
 276                 $under = $preposition === TreeBuilder::UNDER;
 277                 $elementToEnd = null;
 278
 279                 if ( isset( self::$metadataElements[$elementName] ) ) {
 280                         // The element is a metadata element, that we allow to appear in
 281                         // both inline and block contexts.
 282                         $this->trace( 'insert metadata' );
 283                 } elseif ( $under && $parentData->isPWrapper && !$inline ) {
 284                         // [B/b] The element is non-inline and the parent is a p-wrapper,
 285                         // close the parent and insert into its parent instead
 286                         $this->trace( 'insert B/b' );
 287                         $newParent = $this->serializer->getParentNode( $parent );
 288                         $parent = $newParent;
 289                         $parentData = $parent->snData;
 290                         $parentData->childPElement = null;
 291                         $newRef = $refElement->userData;
 292                 } elseif ( $under && $parentData->isSplittable
 293                         && (bool)$parentData->ancestorPNode !== $inline
 294                 ) {
 295                         // [CS/b, DS/i] The parent is splittable and the current element is
 296                         // inline in block context, or if the current element is a block
 297                         // under a p-wrapper, split the tag stack.
 298                         $this->trace( $inline ? 'insert DS/i' : 'insert CS/b' );
 299                         $newRef = $this->splitTagStack( $newRef, $inline, $sourceStart );
 300                         $parent = $newRef;
 301                         $parentData = $parent->snData;
 302                 } elseif ( $under && $parentData->needsPWrapping && $inline ) {
 303                         // [A/i] If the element is inline and we are in body/blockquote,
 304                         // we need to create a p-wrapper
 305                         $this->trace( 'insert A/i' );
 306                         $newRef = $this->insertPWrapper( $newRef, $sourceStart );
 307                         $parent = $newRef;
 308                         $parentData = $parent->snData;
 309                 } elseif ( $parentData->ancestorPNode && !$inline ) {
 310                         // [CU/b] If the element is non-inline and (despite attempting to
 311                         // split above) there is still an ancestor p-wrap, disable that
 312                         // p-wrap
 313                         $this->trace( 'insert CU/b' );
 314                         $this->disablePWrapper( $parent, $sourceStart );
 315                 } else {
 316                         // [A/b, B/i, C/i, D/b, DU/i] insert as normal
 317                         $this->trace( 'insert normal' );
 318                 }
 319
 320                 // An element with element children is a non-blank element
 321                 $parentData->nonblankNodeCount++;
 322
 323                 // Insert the element downstream and so initialise its userData
 324                 $this->serializer->insertElement( $preposition, $newRef,
 325                         $element, $void, $sourceStart, $sourceLength );
 326
 327                 // Initialise snData
 328                 if ( !$element->userData->snData ) {
 329                         $elementData = $element->userData->snData = new RemexMungerData;
 330                 } else {
 331                         $elementData = $element->userData->snData;
 332                 }
 333                 if ( ( $parentData->isPWrapper || $parentData->isSplittable )
 334                         && isset( self::$formattingElements[$elementName] )
 335                 ) {
 336                         $elementData->isSplittable = true;
 337                 }
 338                 if ( $parentData->isPWrapper ) {
 339                         $elementData->ancestorPNode = $parent;
 340                 } elseif ( $parentData->ancestorPNode ) {
 341                         $elementData->ancestorPNode = $parentData->ancestorPNode;
 342                 }
 343                 if ( $parentData->wrapBaseNode ) {
 344                         $elementData->wrapBaseNode = $parentData->wrapBaseNode;
 345                 } elseif ( $parentData->needsPWrapping ) {
 346                         $elementData->wrapBaseNode = $parent;
 347                 }
 348                 if ( $elementName === 'body'
 349                         || $elementName === 'blockquote'
 350                         || $elementName === 'html'
 351                 ) {
 352                         $elementData->needsPWrapping = true;
 353                 }
 354         }
 355
 356         /**
 357          * Clone nodes in a stack range and return the new parent
 358          *
 359          * @param SerializerNode $parentNode
 360          * @param bool $inline
 361          * @param int $pos The source position
 362          * @return SerializerNode
 363          */
 364         private function splitTagStack( SerializerNode $parentNode, $inline, $pos ) {
 365                 $parentData = $parentNode->snData;
 366                 $wrapBase = $parentData->wrapBaseNode;
 367                 $pWrap = $parentData->ancestorPNode;
 368                 if ( !$pWrap ) {
 369                         $cloneEnd = $wrapBase;
 370                 } else {
 371                         $cloneEnd = $parentData->ancestorPNode;
 372                 }
 373
 374                 $serializer = $this->serializer;
 375                 $node = $parentNode;
 376                 $root = $serializer->getRootNode();
 377                 $nodes = [];
 378                 $removableNodes = [];
 379                 while ( $node !== $cloneEnd ) {
 380                         $nextParent = $serializer->getParentNode( $node );
 381                         if ( $nextParent === $root ) {
 382                                 throw new \Exception( 'Did not find end of clone range' );
 383                         }
 384                         $nodes[] = $node;
 385                         if ( $node->snData->nonblankNodeCount === 0 ) {
 386                                 $removableNodes[] = $node;
 387                                 $nextParent->snData->nonblankNodeCount--;
 388                         }
 389                         $node = $nextParent;
 390                 }
 391
 392                 if ( $inline ) {
 393                         $pWrap = $this->insertPWrapper( $wrapBase, $pos );
 394                         $node = $pWrap;
 395                 } else {
 396                         if ( $pWrap ) {
 397                                 // End the p-wrap which was open, cancel the diversion
 398                                 $wrapBase->snData->childPElement = null;
 399                         }
 400                         $pWrap = null;
 401                         $node = $wrapBase;
 402                 }
 403
 404                 for ( $i = count( $nodes ) - 1; $i >= 0; $i-- ) {
 405                         $oldNode = $nodes[$i];
 406                         $oldData = $oldNode->snData;
 407                         $nodeParent = $node;
 408                         $element = new Element( $oldNode->namespace, $oldNode->name, $oldNode->attrs );
 409                         $this->serializer->insertElement( TreeBuilder::UNDER, $nodeParent,
 410                                 $element, false, $pos, 0 );
 411                         $oldData->currentCloneElement = $element;
 412
 413                         $newNode = $element->userData;
 414                         $newData = $newNode->snData = new RemexMungerData;
 415                         if ( $pWrap ) {
 416                                 $newData->ancestorPNode = $pWrap;
 417                         }
 418                         $newData->isSplittable = true;
 419                         $newData->wrapBaseNode = $wrapBase;
 420                         $newData->isPWrapper = $oldData->isPWrapper;
 421
 422                         $nodeParent->snData->nonblankNodeCount++;
 423
 424                         $node = $newNode;
 425                 }
 426                 foreach ( $removableNodes as $rNode ) {
 427                         $fakeElement = new Element( $rNode->namespace, $rNode->name, $rNode->attrs );
 428                         $fakeElement->userData = $rNode;
 429                         $this->serializer->removeNode( $fakeElement, $pos );
 430                 }
 431                 return $node;
 432         }
 433
 434         /**
 435          * Find the ancestor of $node which is a child of a p-wrapper, and
 436          * reparent that node so that it is placed after the end of the p-wrapper
 437          */
 438         private function disablePWrapper( SerializerNode $node, $sourceStart ) {
 439                 $nodeData = $node->snData;
 440                 $pWrapNode = $nodeData->ancestorPNode;
 441                 $newParent = $this->serializer->getParentNode( $pWrapNode );
 442                 if ( $pWrapNode !== $this->serializer->getLastChild( $newParent ) ) {
 443                         // Fostering or something? Abort!
 444                         return;
 445                 }
 446
 447                 $nextParent = $node;
 448                 do {
 449                         $victim = $nextParent;
 450                         $victim->snData->ancestorPNode = null;
 451                         $nextParent = $this->serializer->getParentNode( $victim );
 452                 } while ( $nextParent !== $pWrapNode );
 453
 454                 // Make a fake Element to use in a reparenting operation
 455                 $victimElement = new Element( $victim->namespace, $victim->name, $victim->attrs );
 456                 $victimElement->userData = $victim;
 457
 458                 // Reparent
 459                 $this->serializer->insertElement( TreeBuilder::UNDER, $newParent, $victimElement,
 460                         false, $sourceStart, 0 );
 461
 462                 // Decrement nonblank node count
 463                 $pWrapNode->snData->nonblankNodeCount--;
 464
 465                 // Cancel the diversion so that no more elements are inserted under this p-wrap
 466                 $newParent->snData->childPElement = null;
 467         }
 468
 469         public function endTag( Element $element, $sourceStart, $sourceLength ) {
 470                 $data = $element->userData->snData;
 471                 if ( $data->childPElement ) {
 472                         $this->endTag( $data->childPElement, $sourceStart, 0 );
 473                 }
 474                 $this->serializer->endTag( $element, $sourceStart, $sourceLength );
 475                 $element->userData->snData = null;
 476                 $element->userData = null;
 477         }
 478
 479         public function doctype( $name, $public, $system, $quirks, $sourceStart, $sourceLength ) {
 480                 $this->serializer->doctype( $name, $public,  $system, $quirks,
 481                         $sourceStart, $sourceLength );
 482         }
 483
 484         public function comment( $preposition, $refElement, $text, $sourceStart, $sourceLength ) {
 485                 list( , $refNode ) = $this->getParentForInsert( $preposition, $refElement );
 486                 $this->serializer->comment( $preposition, $refNode, $text, $sourceStart, $sourceLength );
 487         }
 488
 489         public function error( $text, $pos ) {
 490                 $this->serializer->error( $text, $pos );
 491         }
 492
 493         public function mergeAttributes( Element $element, Attributes $attrs, $sourceStart ) {
 494                 $this->serializer->mergeAttributes( $element, $attrs, $sourceStart );
 495         }
 496
 497         public function removeNode( Element $element, $sourceStart ) {
 498                 $this->serializer->removeNode( $element, $sourceStart );
 499         }
 500
 501         public function reparentChildren( Element $element, Element $newParent, $sourceStart ) {
 502                 $self = $element->userData;
 503                 if ( $self->snData->childPElement ) {
 504                         // Reparent under the p-wrapper instead, so that e.g.
 505                         //   <blockquote><mw:p-wrap>...</mw:p-wrap></blockquote>
 506                         // becomes
 507                         //   <blockquote><mw:p-wrap><i>...</i></mw:p-wrap></blockquote>
 508
 509                         // The formatting element should not be the parent of the p-wrap.
 510                         // Without this special case, the insertElement() of the <i> below
 511                         // would be diverted into the p-wrapper, causing infinite recursion
 512                         // (T178632)
 513                         $this->reparentChildren( $self->snData->childPElement, $newParent, $sourceStart );
 514                         return;
 515                 }
 516
 517                 $children = $self->children;
 518                 $self->children = [];
 519                 $this->insertElement( TreeBuilder::UNDER, $element, $newParent, false, $sourceStart, 0 );
 520                 $newParentNode = $newParent->userData;
 521                 $newParentId = $newParentNode->id;
 522                 foreach ( $children as $child ) {
 523                         if ( is_object( $child ) ) {
 524                                 $this->trace( "reparent <{$child->name}>" );
 525                                 $child->parentId = $newParentId;
 526                         }
 527                 }
 528                 $newParentNode->children = $children;
 529         }
 530 }