includes/parser/BlockLevelPass.php

   1 <?php
   2
   3 /**
   4  * This is the part of the wikitext parser which handles automatic paragraphs
   5  * and conversion of start-of-line prefixes to HTML lists.
   6  *
   7  * This program is free software; you can redistribute it and/or modify
   8  * it under the terms of the GNU General Public License as published by
   9  * the Free Software Foundation; either version 2 of the License, or
  10  * (at your option) any later version.
  11  *
  12  * This program is distributed in the hope that it will be useful,
  13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  15  * GNU General Public License for more details.
  16  *
  17  * You should have received a copy of the GNU General Public License along
  18  * with this program; if not, write to the Free Software Foundation, Inc.,
  19  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
  20  * http://www.gnu.org/copyleft/gpl.html
  21  *
  22  * @file
  23  * @ingroup Parser
  24  */
  25 class BlockLevelPass {
  26         private $DTopen = false;
  27         private $inPre = false;
  28         private $lastParagraph = '';
  29         private $lineStart;
  30         private $text;
  31
  32         # State constants for the definition list colon extraction
  33         const COLON_STATE_TEXT = 0;
  34         const COLON_STATE_TAG = 1;
  35         const COLON_STATE_TAGSTART = 2;
  36         const COLON_STATE_CLOSETAG = 3;
  37         const COLON_STATE_TAGSLASH = 4;
  38         const COLON_STATE_COMMENT = 5;
  39         const COLON_STATE_COMMENTDASH = 6;
  40         const COLON_STATE_COMMENTDASHDASH = 7;
  41         const COLON_STATE_LC = 8;
  42
  43         /**
  44          * Make lists from lines starting with ':', '*', '#', etc.
  45          *
  46          * @param string $text
  47          * @param bool $lineStart Whether or not this is at the start of a line.
  48          * @return string The lists rendered as HTML
  49          */
  50         public static function doBlockLevels( $text, $lineStart ) {
  51                 $pass = new self( $text, $lineStart );
  52                 return $pass->execute();
  53         }
  54
  55         /**
  56          * @param string $text
  57          * @param bool $lineStart
  58          */
  59         private function __construct( $text, $lineStart ) {
  60                 $this->text = $text;
  61                 $this->lineStart = $lineStart;
  62         }
  63
  64         /**
  65          * @return bool
  66          */
  67         private function hasOpenParagraph() {
  68                 return $this->lastParagraph !== '';
  69         }
  70
  71         /**
  72          * If a pre or p is open, return the corresponding close tag and update
  73          * the state. If no tag is open, return an empty string.
  74          * @param bool $atTheEnd Omit trailing newline if we've reached the end.
  75          * @return string
  76          */
  77         private function closeParagraph( $atTheEnd = false ) {
  78                 $result = '';
  79                 if ( $this->hasOpenParagraph() ) {
  80                         $result = '</' . $this->lastParagraph . '>';
  81                         if ( !$atTheEnd ) {
  82                                 $result .= "\n";
  83                         }
  84                 }
  85                 $this->inPre = false;
  86                 $this->lastParagraph = '';
  87                 return $result;
  88         }
  89
  90         /**
  91          * getCommon() returns the length of the longest common substring
  92          * of both arguments, starting at the beginning of both.
  93          *
  94          * @param string $st1
  95          * @param string $st2
  96          *
  97          * @return int
  98          */
  99         private function getCommon( $st1, $st2 ) {
 100                 $shorter = min( strlen( $st1 ), strlen( $st2 ) );
 101
 102                 for ( $i = 0; $i < $shorter; ++$i ) {
 103                         if ( $st1[$i] !== $st2[$i] ) {
 104                                 break;
 105                         }
 106                 }
 107                 return $i;
 108         }
 109
 110         /**
 111          * Open the list item element identified by the prefix character.
 112          *
 113          * @param string $char
 114          *
 115          * @return string
 116          */
 117         private function openList( $char ) {
 118                 $result = $this->closeParagraph();
 119
 120                 if ( $char === '*' ) {
 121                         $result .= "<ul><li>";
 122                 } elseif ( $char === '#' ) {
 123                         $result .= "<ol><li>";
 124                 } elseif ( $char === ':' ) {
 125                         $result .= "<dl><dd>";
 126                 } elseif ( $char === ';' ) {
 127                         $result .= "<dl><dt>";
 128                         $this->DTopen = true;
 129                 } else {
 130                         $result = '<!-- ERR 1 -->';
 131                 }
 132
 133                 return $result;
 134         }
 135
 136         /**
 137          * Close the current list item and open the next one.
 138          * @param string $char
 139          *
 140          * @return string
 141          */
 142         private function nextItem( $char ) {
 143                 if ( $char === '*' || $char === '#' ) {
 144                         return "</li>\n<li>";
 145                 } elseif ( $char === ':' || $char === ';' ) {
 146                         $close = "</dd>\n";
 147                         if ( $this->DTopen ) {
 148                                 $close = "</dt>\n";
 149                         }
 150                         if ( $char === ';' ) {
 151                                 $this->DTopen = true;
 152                                 return $close . '<dt>';
 153                         } else {
 154                                 $this->DTopen = false;
 155                                 return $close . '<dd>';
 156                         }
 157                 }
 158                 return '<!-- ERR 2 -->';
 159         }
 160
 161         /**
 162          * Close the current list item identified by the prefix character.
 163          * @param string $char
 164          *
 165          * @return string
 166          */
 167         private function closeList( $char ) {
 168                 if ( $char === '*' ) {
 169                         $text = "</li></ul>";
 170                 } elseif ( $char === '#' ) {
 171                         $text = "</li></ol>";
 172                 } elseif ( $char === ':' ) {
 173                         if ( $this->DTopen ) {
 174                                 $this->DTopen = false;
 175                                 $text = "</dt></dl>";
 176                         } else {
 177                                 $text = "</dd></dl>";
 178                         }
 179                 } else {
 180                         return '<!-- ERR 3 -->';
 181                 }
 182                 return $text;
 183         }
 184
 185         /**
 186          * Execute the pass.
 187          * @return string
 188          */
 189         private function execute() {
 190                 $text = $this->text;
 191                 # Parsing through the text line by line.  The main thing
 192                 # happening here is handling of block-level elements p, pre,
 193                 # and making lists from lines starting with * # : etc.
 194                 $textLines = StringUtils::explode( "\n", $text );
 195
 196                 $lastPrefix = $output = '';
 197                 $this->DTopen = $inBlockElem = false;
 198                 $prefixLength = 0;
 199                 $pendingPTag = false;
 200                 $inBlockquote = false;
 201
 202                 for ( $textLines->rewind(); $textLines->valid(); ) {
 203                         $inputLine = $textLines->current();
 204                         $textLines->next();
 205                         $notLastLine = $textLines->valid();
 206
 207                         # Fix up $lineStart
 208                         if ( !$this->lineStart ) {
 209                                 $output .= $inputLine;
 210                                 $this->lineStart = true;
 211                                 continue;
 212                         }
 213                         # * = ul
 214                         # # = ol
 215                         # ; = dt
 216                         # : = dd
 217
 218                         $lastPrefixLength = strlen( $lastPrefix );
 219                         $preCloseMatch = preg_match( '/<\\/pre/i', $inputLine );
 220                         $preOpenMatch = preg_match( '/<pre/i', $inputLine );
 221                         # If not in a <pre> element, scan for and figure out what prefixes are there.
 222                         if ( !$this->inPre ) {
 223                                 # Multiple prefixes may abut each other for nested lists.
 224                                 $prefixLength = strspn( $inputLine, '*#:;' );
 225                                 $prefix = substr( $inputLine, 0, $prefixLength );
 226
 227                                 # eh?
 228                                 # ; and : are both from definition-lists, so they're equivalent
 229                                 #  for the purposes of determining whether or not we need to open/close
 230                                 #  elements.
 231                                 $prefix2 = str_replace( ';', ':', $prefix );
 232                                 $t = substr( $inputLine, $prefixLength );
 233                                 $this->inPre = (bool)$preOpenMatch;
 234                         } else {
 235                                 # Don't interpret any other prefixes in preformatted text
 236                                 $prefixLength = 0;
 237                                 $prefix = $prefix2 = '';
 238                                 $t = $inputLine;
 239                         }
 240
 241                         # List generation
 242                         if ( $prefixLength && $lastPrefix === $prefix2 ) {
 243                                 # Same as the last item, so no need to deal with nesting or opening stuff
 244                                 $output .= $this->nextItem( substr( $prefix, -1 ) );
 245                                 $pendingPTag = false;
 246
 247                                 if ( substr( $prefix, -1 ) === ';' ) {
 248                                         # The one nasty exception: definition lists work like this:
 249                                         # ; title : definition text
 250                                         # So we check for : in the remainder text to split up the
 251                                         # title and definition, without b0rking links.
 252                                         $term = $t2 = '';
 253                                         if ( $this->findColonNoLinks( $t, $term, $t2 ) !== false ) {
 254                                                 $t = $t2;
 255                                                 // Trim whitespace in list items
 256                                                 $output .= trim( $term ) . $this->nextItem( ':' );
 257                                         }
 258                                 }
 259                         } elseif ( $prefixLength || $lastPrefixLength ) {
 260                                 # We need to open or close prefixes, or both.
 261
 262                                 # Either open or close a level...
 263                                 $commonPrefixLength = $this->getCommon( $prefix, $lastPrefix );
 264                                 $pendingPTag = false;
 265
 266                                 # Close all the prefixes which aren't shared.
 267                                 while ( $commonPrefixLength < $lastPrefixLength ) {
 268                                         $output .= $this->closeList( $lastPrefix[$lastPrefixLength - 1] );
 269                                         --$lastPrefixLength;
 270                                 }
 271
 272                                 # Continue the current prefix if appropriate.
 273                                 if ( $prefixLength <= $commonPrefixLength && $commonPrefixLength > 0 ) {
 274                                         $output .= $this->nextItem( $prefix[$commonPrefixLength - 1] );
 275                                 }
 276
 277                                 # Close an open <dt> if we have a <dd> (":") starting on this line
 278                                 if ( $this->DTopen && $commonPrefixLength > 0 && $prefix[$commonPrefixLength - 1] === ':' ) {
 279                                         $output .= $this->nextItem( ':' );
 280                                 }
 281
 282                                 # Open prefixes where appropriate.
 283                                 if ( $lastPrefix && $prefixLength > $commonPrefixLength ) {
 284                                         $output .= "\n";
 285                                 }
 286                                 while ( $prefixLength > $commonPrefixLength ) {
 287                                         $char = $prefix[$commonPrefixLength];
 288                                         $output .= $this->openList( $char );
 289
 290                                         if ( $char === ';' ) {
 291                                                 # @todo FIXME: This is dupe of code above
 292                                                 if ( $this->findColonNoLinks( $t, $term, $t2 ) !== false ) {
 293                                                         $t = $t2;
 294                                                         // Trim whitespace in list items
 295                                                         $output .= trim( $term ) . $this->nextItem( ':' );
 296                                                 }
 297                                         }
 298                                         ++$commonPrefixLength;
 299                                 }
 300                                 if ( !$prefixLength && $lastPrefix ) {
 301                                         $output .= "\n";
 302                                 }
 303                                 $lastPrefix = $prefix2;
 304                         }
 305
 306                         # If we have no prefixes, go to paragraph mode.
 307                         if ( $prefixLength == 0 ) {
 308                                 # No prefix (not in list)--go to paragraph mode
 309                                 # @todo consider using a stack for nestable elements like span, table and div
 310
 311                                 // P-wrapping and indent-pre are suppressed inside, not outside
 312                                 $blockElems = 'table|h1|h2|h3|h4|h5|h6|pre|p|ul|ol|dl';
 313                                 // P-wrapping and indent-pre are suppressed outside, not inside
 314                                 $antiBlockElems = 'td|th';
 315
 316                                 $openMatch = preg_match(
 317                                         '/<('
 318                                                 . "({$blockElems})|\\/({$antiBlockElems})|"
 319                                                 // Always suppresses
 320                                                 . '\\/?(tr|dt|dd|li)'
 321                                                 . ')\\b/iS',
 322                                         $t
 323                                 );
 324                                 $closeMatch = preg_match(
 325                                         '/<('
 326                                                 . "\\/({$blockElems})|({$antiBlockElems})|"
 327                                                 // Never suppresses
 328                                                 . '\\/?(center|blockquote|div|hr|mw:)'
 329                                                 . ')\\b/iS',
 330                                         $t
 331                                 );
 332
 333                                 // Any match closes the paragraph, but only when `!$closeMatch`
 334                                 // do we enter block mode.  The oddities with table rows and
 335                                 // cells are to avoid paragraph wrapping in interstitial spaces
 336                                 // leading to fostered content.
 337
 338                                 if ( $openMatch || $closeMatch ) {
 339                                         $pendingPTag = false;
 340                                         // Only close the paragraph if we're not inside a <pre> tag, or if
 341                                         // that <pre> tag has just been opened
 342                                         if ( !$this->inPre || $preOpenMatch ) {
 343                                                 // @todo T7718: paragraph closed
 344                                                 $output .= $this->closeParagraph();
 345                                         }
 346                                         if ( $preOpenMatch && !$preCloseMatch ) {
 347                                                 $this->inPre = true;
 348                                         }
 349                                         $bqOffset = 0;
 350                                         while ( preg_match( '/<(\\/?)blockquote[\s>]/i', $t,
 351                                                 $bqMatch, PREG_OFFSET_CAPTURE, $bqOffset )
 352                                         ) {
 353                                                 $inBlockquote = !$bqMatch[1][0]; // is this a close tag?
 354                                                 $bqOffset = $bqMatch[0][1] + strlen( $bqMatch[0][0] );
 355                                         }
 356                                         $inBlockElem = !$closeMatch;
 357                                 } elseif ( !$inBlockElem && !$this->inPre ) {
 358                                         if ( substr( $t, 0, 1 ) == ' '
 359                                                 && ( $this->lastParagraph === 'pre' || trim( $t ) != '' )
 360                                                 && !$inBlockquote
 361                                         ) {
 362                                                 # pre
 363                                                 if ( $this->lastParagraph !== 'pre' ) {
 364                                                         $pendingPTag = false;
 365                                                         $output .= $this->closeParagraph() . '<pre>';
 366                                                         $this->lastParagraph = 'pre';
 367                                                 }
 368                                                 $t = substr( $t, 1 );
 369                                         } elseif ( preg_match( '/^(?:<style\\b[^>]*>.*?<\\/style>\s*|<link\\b[^>]*>\s*)+$/iS', $t ) ) {
 370                                                 # T186965: <style> or <link> by itself on a line shouldn't open or close paragraphs.
 371                                                 # But it should clear $pendingPTag.
 372                                                 if ( $pendingPTag ) {
 373                                                         $output .= $this->closeParagraph();
 374                                                         $pendingPTag = false;
 375                                                 }
 376                                         } else {
 377                                                 # paragraph
 378                                                 if ( trim( $t ) === '' ) {
 379                                                         if ( $pendingPTag ) {
 380                                                                 $output .= $pendingPTag . '<br />';
 381                                                                 $pendingPTag = false;
 382                                                                 $this->lastParagraph = 'p';
 383                                                         } else {
 384                                                                 if ( $this->lastParagraph !== 'p' ) {
 385                                                                         $output .= $this->closeParagraph();
 386                                                                         $pendingPTag = '<p>';
 387                                                                 } else {
 388                                                                         $pendingPTag = '</p><p>';
 389                                                                 }
 390                                                         }
 391                                                 } else {
 392                                                         if ( $pendingPTag ) {
 393                                                                 $output .= $pendingPTag;
 394                                                                 $pendingPTag = false;
 395                                                                 $this->lastParagraph = 'p';
 396                                                         } elseif ( $this->lastParagraph !== 'p' ) {
 397                                                                 $output .= $this->closeParagraph() . '<p>';
 398                                                                 $this->lastParagraph = 'p';
 399                                                         }
 400                                                 }
 401                                         }
 402                                 }
 403                         }
 404                         # somewhere above we forget to get out of pre block (T2785)
 405                         if ( $preCloseMatch && $this->inPre ) {
 406                                 $this->inPre = false;
 407                         }
 408                         if ( $pendingPTag === false ) {
 409                                 if ( $prefixLength === 0 ) {
 410                                         $output .= $t;
 411                                         // Add a newline if there's an open paragraph
 412                                         // or we've yet to reach the last line.
 413                                         if ( $notLastLine || $this->hasOpenParagraph() ) {
 414                                                 $output .= "\n";
 415                                         }
 416                                 } else {
 417                                         // Trim whitespace in list items
 418                                         $output .= trim( $t );
 419                                 }
 420                         }
 421                 }
 422                 while ( $prefixLength ) {
 423                         $output .= $this->closeList( $prefix2[$prefixLength - 1] );
 424                         --$prefixLength;
 425                         // Note that a paragraph is only ever opened when `prefixLength`
 426                         // is zero, but we'll choose to be overly cautious.
 427                         if ( !$prefixLength && $this->hasOpenParagraph() ) {
 428                                 $output .= "\n";
 429                         }
 430                 }
 431                 $output .= $this->closeParagraph( true );
 432                 return $output;
 433         }
 434
 435         /**
 436          * Split up a string on ':', ignoring any occurrences inside tags
 437          * to prevent illegal overlapping.
 438          *
 439          * @param string $str The string to split
 440          * @param string &$before Set to everything before the ':'
 441          * @param string &$after Set to everything after the ':'
 442          * @throws MWException
 443          * @return string The position of the ':', or false if none found
 444          */
 445         private function findColonNoLinks( $str, &$before, &$after ) {
 446                 if ( !preg_match( '/:|<|-\{/', $str, $m, PREG_OFFSET_CAPTURE ) ) {
 447                         # Nothing to find!
 448                         return false;
 449                 }
 450
 451                 if ( $m[0][0] === ':' ) {
 452                         # Easy; no tag nesting to worry about
 453                         $colonPos = $m[0][1];
 454                         $before = substr( $str, 0, $colonPos );
 455                         $after = substr( $str, $colonPos + 1 );
 456                         return $colonPos;
 457                 }
 458
 459                 # Ugly state machine to walk through avoiding tags.
 460                 $state = self::COLON_STATE_TEXT;
 461                 $ltLevel = 0;
 462                 $lcLevel = 0;
 463                 $len = strlen( $str );
 464                 for ( $i = $m[0][1]; $i < $len; $i++ ) {
 465                         $c = $str[$i];
 466
 467                         switch ( $state ) {
 468                                 case self::COLON_STATE_TEXT:
 469                                         switch ( $c ) {
 470                                                 case "<":
 471                                                         # Could be either a <start> tag or an </end> tag
 472                                                         $state = self::COLON_STATE_TAGSTART;
 473                                                         break;
 474                                                 case ":":
 475                                                         if ( $ltLevel === 0 ) {
 476                                                                 # We found it!
 477                                                                 $before = substr( $str, 0, $i );
 478                                                                 $after = substr( $str, $i + 1 );
 479                                                                 return $i;
 480                                                         }
 481                                                         # Embedded in a tag; don't break it.
 482                                                         break;
 483                                                 default:
 484                                                         # Skip ahead looking for something interesting
 485                                                         if ( !preg_match( '/:|<|-\{/', $str, $m, PREG_OFFSET_CAPTURE, $i ) ) {
 486                                                                 # Nothing else interesting
 487                                                                 return false;
 488                                                         }
 489                                                         if ( $m[0][0] === '-{' ) {
 490                                                                 $state = self::COLON_STATE_LC;
 491                                                                 $lcLevel++;
 492                                                                 $i = $m[0][1] + 1;
 493                                                         } else {
 494                                                                 # Skip ahead to next interesting character.
 495                                                                 $i = $m[0][1] - 1;
 496                                                         }
 497                                                         break;
 498                                         }
 499                                         break;
 500                                 case self::COLON_STATE_LC:
 501                                         # In language converter markup -{ ... }-
 502                                         if ( !preg_match( '/-\{|\}-/', $str, $m, PREG_OFFSET_CAPTURE, $i ) ) {
 503                                                 # Nothing else interesting to find; abort!
 504                                                 # We're nested in language converter markup, but there
 505                                                 # are no close tags left.  Abort!
 506                                                 break 2;
 507                                         } elseif ( $m[0][0] === '-{' ) {
 508                                                 $i = $m[0][1] + 1;
 509                                                 $lcLevel++;
 510                                         } elseif ( $m[0][0] === '}-' ) {
 511                                                 $i = $m[0][1] + 1;
 512                                                 $lcLevel--;
 513                                                 if ( $lcLevel === 0 ) {
 514                                                         $state = self::COLON_STATE_TEXT;
 515                                                 }
 516                                         }
 517                                         break;
 518                                 case self::COLON_STATE_TAG:
 519                                         # In a <tag>
 520                                         switch ( $c ) {
 521                                                 case ">":
 522                                                         $ltLevel++;
 523                                                         $state = self::COLON_STATE_TEXT;
 524                                                         break;
 525                                                 case "/":
 526                                                         # Slash may be followed by >?
 527                                                         $state = self::COLON_STATE_TAGSLASH;
 528                                                         break;
 529                                                 default:
 530                                                         # ignore
 531                                         }
 532                                         break;
 533                                 case self::COLON_STATE_TAGSTART:
 534                                         switch ( $c ) {
 535                                                 case "/":
 536                                                         $state = self::COLON_STATE_CLOSETAG;
 537                                                         break;
 538                                                 case "!":
 539                                                         $state = self::COLON_STATE_COMMENT;
 540                                                         break;
 541                                                 case ">":
 542                                                         # Illegal early close? This shouldn't happen D:
 543                                                         $state = self::COLON_STATE_TEXT;
 544                                                         break;
 545                                                 default:
 546                                                         $state = self::COLON_STATE_TAG;
 547                                         }
 548                                         break;
 549                                 case self::COLON_STATE_CLOSETAG:
 550                                         # In a </tag>
 551                                         if ( $c === ">" ) {
 552                                                 if ( $ltLevel > 0 ) {
 553                                                         $ltLevel--;
 554                                                 } else {
 555                                                         # ignore the excess close tag, but keep looking for
 556                                                         # colons. (This matches Parsoid behavior.)
 557                                                         wfDebug( __METHOD__ . ": Invalid input; too many close tags\n" );
 558                                                 }
 559                                                 $state = self::COLON_STATE_TEXT;
 560                                         }
 561                                         break;
 562                                 case self::COLON_STATE_TAGSLASH:
 563                                         if ( $c === ">" ) {
 564                                                 # Yes, a self-closed tag <blah/>
 565                                                 $state = self::COLON_STATE_TEXT;
 566                                         } else {
 567                                                 # Probably we're jumping the gun, and this is an attribute
 568                                                 $state = self::COLON_STATE_TAG;
 569                                         }
 570                                         break;
 571                                 case self::COLON_STATE_COMMENT:
 572                                         if ( $c === "-" ) {
 573                                                 $state = self::COLON_STATE_COMMENTDASH;
 574                                         }
 575                                         break;
 576                                 case self::COLON_STATE_COMMENTDASH:
 577                                         if ( $c === "-" ) {
 578                                                 $state = self::COLON_STATE_COMMENTDASHDASH;
 579                                         } else {
 580                                                 $state = self::COLON_STATE_COMMENT;
 581                                         }
 582                                         break;
 583                                 case self::COLON_STATE_COMMENTDASHDASH:
 584                                         if ( $c === ">" ) {
 585                                                 $state = self::COLON_STATE_TEXT;
 586                                         } else {
 587                                                 $state = self::COLON_STATE_COMMENT;
 588                                         }
 589                                         break;
 590                                 default:
 591                                         throw new MWException( "State machine error in " . __METHOD__ );
 592                         }
 593                 }
 594                 if ( $ltLevel > 0 || $lcLevel > 0 ) {
 595                         wfDebug(
 596                                 __METHOD__ . ": Invalid input; not enough close tags " .
 597                                 "(level $ltLevel/$lcLevel, state $state)\n"
 598                         );
 599                         return false;
 600                 }
 601                 return false;
 602         }
 603 }