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