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          * Private constructor
  57          */
  58         private function __construct( $text, $lineStart ) {
  59                 $this->text = $text;
  60                 $this->lineStart = $lineStart;
  61         }
  62
  63         /**
  64          * If a pre or p is open, return the corresponding close tag and update
  65          * the state. If no tag is open, return an empty string.
  66          * @return string
  67          */
  68         private function closeParagraph() {
  69                 $result = '';
  70                 if ( $this->lastSection !== '' ) {
  71                         $result = '</' . $this->lastSection . ">\n";
  72                 }
  73                 $this->inPre = false;
  74                 $this->lastSection = '';
  75                 return $result;
  76         }
  77
  78         /**
  79          * getCommon() returns the length of the longest common substring
  80          * of both arguments, starting at the beginning of both.
  81          *
  82          * @param string $st1
  83          * @param string $st2
  84          *
  85          * @return int
  86          */
  87         private function getCommon( $st1, $st2 ) {
  88                 $shorter = min( strlen( $st1 ), strlen( $st2 ) );
  89
  90                 for ( $i = 0; $i < $shorter; ++$i ) {
  91                         if ( $st1[$i] !== $st2[$i] ) {
  92                                 break;
  93                         }
  94                 }
  95                 return $i;
  96         }
  97
  98         /**
  99          * Open the list item element identified by the prefix character.
 100          *
 101          * @param string $char
 102          *
 103          * @return string
 104          */
 105         private function openList( $char ) {
 106                 $result = $this->closeParagraph();
 107
 108                 if ( '*' === $char ) {
 109                         $result .= "<ul><li>";
 110                 } elseif ( '#' === $char ) {
 111                         $result .= "<ol><li>";
 112                 } elseif ( ':' === $char ) {
 113                         $result .= "<dl><dd>";
 114                 } elseif ( ';' === $char ) {
 115                         $result .= "<dl><dt>";
 116                         $this->DTopen = true;
 117                 } else {
 118                         $result = '<!-- ERR 1 -->';
 119                 }
 120
 121                 return $result;
 122         }
 123
 124         /**
 125          * Close the current list item and open the next one.
 126          * @param string $char
 127          *
 128          * @return string
 129          */
 130         private function nextItem( $char ) {
 131                 if ( '*' === $char || '#' === $char ) {
 132                         return "</li>\n<li>";
 133                 } elseif ( ':' === $char || ';' === $char ) {
 134                         $close = "</dd>\n";
 135                         if ( $this->DTopen ) {
 136                                 $close = "</dt>\n";
 137                         }
 138                         if ( ';' === $char ) {
 139                                 $this->DTopen = true;
 140                                 return $close . '<dt>';
 141                         } else {
 142                                 $this->DTopen = false;
 143                                 return $close . '<dd>';
 144                         }
 145                 }
 146                 return '<!-- ERR 2 -->';
 147         }
 148
 149         /**
 150          * Close the current list item identified by the prefix character.
 151          * @param string $char
 152          *
 153          * @return string
 154          */
 155         private function closeList( $char ) {
 156                 if ( '*' === $char ) {
 157                         $text = "</li></ul>";
 158                 } elseif ( '#' === $char ) {
 159                         $text = "</li></ol>";
 160                 } elseif ( ':' === $char ) {
 161                         if ( $this->DTopen ) {
 162                                 $this->DTopen = false;
 163                                 $text = "</dt></dl>";
 164                         } else {
 165                                 $text = "</dd></dl>";
 166                         }
 167                 } else {
 168                         return '<!-- ERR 3 -->';
 169                 }
 170                 return $text;
 171         }
 172
 173         /**
 174          * Execute the pass.
 175          * @return string
 176          */
 177         private function execute() {
 178                 $text = $this->text;
 179                 # Parsing through the text line by line.  The main thing
 180                 # happening here is handling of block-level elements p, pre,
 181                 # and making lists from lines starting with * # : etc.
 182                 $textLines = StringUtils::explode( "\n", $text );
 183
 184                 $lastPrefix = $output = '';
 185                 $this->DTopen = $inBlockElem = false;
 186                 $prefixLength = 0;
 187                 $pendingPTag = false;
 188                 $inBlockquote = false;
 189
 190                 foreach ( $textLines as $inputLine ) {
 191                         # Fix up $lineStart
 192                         if ( !$this->lineStart ) {
 193                                 $output .= $inputLine;
 194                                 $this->lineStart = true;
 195                                 continue;
 196                         }
 197                         # * = ul
 198                         # # = ol
 199                         # ; = dt
 200                         # : = dd
 201
 202                         $lastPrefixLength = strlen( $lastPrefix );
 203                         $preCloseMatch = preg_match( '/<\\/pre/i', $inputLine );
 204                         $preOpenMatch = preg_match( '/<pre/i', $inputLine );
 205                         # If not in a <pre> element, scan for and figure out what prefixes are there.
 206                         if ( !$this->inPre ) {
 207                                 # Multiple prefixes may abut each other for nested lists.
 208                                 $prefixLength = strspn( $inputLine, '*#:;' );
 209                                 $prefix = substr( $inputLine, 0, $prefixLength );
 210
 211                                 # eh?
 212                                 # ; and : are both from definition-lists, so they're equivalent
 213                                 #  for the purposes of determining whether or not we need to open/close
 214                                 #  elements.
 215                                 $prefix2 = str_replace( ';', ':', $prefix );
 216                                 $t = substr( $inputLine, $prefixLength );
 217                                 $this->inPre = (bool)$preOpenMatch;
 218                         } else {
 219                                 # Don't interpret any other prefixes in preformatted text
 220                                 $prefixLength = 0;
 221                                 $prefix = $prefix2 = '';
 222                                 $t = $inputLine;
 223                         }
 224
 225                         # List generation
 226                         if ( $prefixLength && $lastPrefix === $prefix2 ) {
 227                                 # Same as the last item, so no need to deal with nesting or opening stuff
 228                                 $output .= $this->nextItem( substr( $prefix, -1 ) );
 229                                 $pendingPTag = false;
 230
 231                                 if ( substr( $prefix, -1 ) === ';' ) {
 232                                         # The one nasty exception: definition lists work like this:
 233                                         # ; title : definition text
 234                                         # So we check for : in the remainder text to split up the
 235                                         # title and definition, without b0rking links.
 236                                         $term = $t2 = '';
 237                                         if ( $this->findColonNoLinks( $t, $term, $t2 ) !== false ) {
 238                                                 $t = $t2;
 239                                                 // Trim whitespace in list items
 240                                                 $output .= trim( $term ) . $this->nextItem( ':' );
 241                                         }
 242                                 }
 243                         } elseif ( $prefixLength || $lastPrefixLength ) {
 244                                 # We need to open or close prefixes, or both.
 245
 246                                 # Either open or close a level...
 247                                 $commonPrefixLength = $this->getCommon( $prefix, $lastPrefix );
 248                                 $pendingPTag = false;
 249
 250                                 # Close all the prefixes which aren't shared.
 251                                 while ( $commonPrefixLength < $lastPrefixLength ) {
 252                                         $output .= $this->closeList( $lastPrefix[$lastPrefixLength - 1] );
 253                                         --$lastPrefixLength;
 254                                 }
 255
 256                                 # Continue the current prefix if appropriate.
 257                                 if ( $prefixLength <= $commonPrefixLength && $commonPrefixLength > 0 ) {
 258                                         $output .= $this->nextItem( $prefix[$commonPrefixLength - 1] );
 259                                 }
 260
 261                                 # Close an open <dt> if we have a <dd> (":") starting on this line
 262                                 if ( $this->DTopen && $commonPrefixLength > 0 && $prefix[$commonPrefixLength - 1] === ':' ) {
 263                                         $output .= $this->nextItem( ':' );
 264                                 }
 265
 266                                 # Open prefixes where appropriate.
 267                                 if ( $lastPrefix && $prefixLength > $commonPrefixLength ) {
 268                                         $output .= "\n";
 269                                 }
 270                                 while ( $prefixLength > $commonPrefixLength ) {
 271                                         $char = $prefix[$commonPrefixLength];
 272                                         $output .= $this->openList( $char );
 273
 274                                         if ( ';' === $char ) {
 275                                                 # @todo FIXME: This is dupe of code above
 276                                                 if ( $this->findColonNoLinks( $t, $term, $t2 ) !== false ) {
 277                                                         $t = $t2;
 278                                                         // Trim whitespace in list items
 279                                                         $output .= trim( $term ) . $this->nextItem( ':' );
 280                                                 }
 281                                         }
 282                                         ++$commonPrefixLength;
 283                                 }
 284                                 if ( !$prefixLength && $lastPrefix ) {
 285                                         $output .= "\n";
 286                                 }
 287                                 $lastPrefix = $prefix2;
 288                         }
 289
 290                         # If we have no prefixes, go to paragraph mode.
 291                         if ( 0 == $prefixLength ) {
 292                                 # No prefix (not in list)--go to paragraph mode
 293                                 # @todo consider using a stack for nestable elements like span, table and div
 294                                 $openMatch = preg_match(
 295                                         '/(?:<table|<h1|<h2|<h3|<h4|<h5|<h6|<pre|<tr|'
 296                                                 . '<p|<ul|<ol|<dl|<li|<\\/tr|<\\/td|<\\/th)\\b/iS',
 297                                         $t
 298                                 );
 299                                 $closeMatch = preg_match(
 300                                         '/(?:<\\/table|<\\/h1|<\\/h2|<\\/h3|<\\/h4|<\\/h5|<\\/h6|'
 301                                                 . '<td|<th|<\\/?blockquote|<\\/?div|<hr|<\\/pre|<\\/p|<\\/mw:|'
 302                                                 . Parser::MARKER_PREFIX
 303                                                 . '-pre|<\\/li|<\\/ul|<\\/ol|<\\/dl|<\\/?center)\\b/iS',
 304                                         $t
 305                                 );
 306
 307                                 if ( $openMatch || $closeMatch ) {
 308                                         $pendingPTag = false;
 309                                         # @todo T7718: paragraph closed
 310                                         $output .= $this->closeParagraph();
 311                                         if ( $preOpenMatch && !$preCloseMatch ) {
 312                                                 $this->inPre = true;
 313                                         }
 314                                         $bqOffset = 0;
 315                                         while ( preg_match( '/<(\\/?)blockquote[\s>]/i', $t,
 316                                                 $bqMatch, PREG_OFFSET_CAPTURE, $bqOffset )
 317                                         ) {
 318                                                 $inBlockquote = !$bqMatch[1][0]; // is this a close tag?
 319                                                 $bqOffset = $bqMatch[0][1] + strlen( $bqMatch[0][0] );
 320                                         }
 321                                         $inBlockElem = !$closeMatch;
 322                                 } elseif ( !$inBlockElem && !$this->inPre ) {
 323                                         if ( ' ' == substr( $t, 0, 1 )
 324                                                 && ( $this->lastSection === 'pre' || trim( $t ) != '' )
 325                                                 && !$inBlockquote
 326                                         ) {
 327                                                 # pre
 328                                                 if ( $this->lastSection !== 'pre' ) {
 329                                                         $pendingPTag = false;
 330                                                         $output .= $this->closeParagraph() . '<pre>';
 331                                                         $this->lastSection = 'pre';
 332                                                 }
 333                                                 $t = substr( $t, 1 );
 334                                         } elseif ( preg_match( '/^(?:<style\\b[^>]*>.*?<\\/style>\s*|<link\\b[^>]*>\s*)+$/iS', $t ) ) {
 335                                                 # T186965: <style> or <link> by itself on a line shouldn't open or close paragraphs.
 336                                                 # But it should clear $pendingPTag.
 337                                                 if ( $pendingPTag ) {
 338                                                         $output .= $this->closeParagraph();
 339                                                         $pendingPTag = false;
 340                                                         $this->lastSection = '';
 341                                                 }
 342                                         } else {
 343                                                 # paragraph
 344                                                 if ( trim( $t ) === '' ) {
 345                                                         if ( $pendingPTag ) {
 346                                                                 $output .= $pendingPTag . '<br />';
 347                                                                 $pendingPTag = false;
 348                                                                 $this->lastSection = 'p';
 349                                                         } else {
 350                                                                 if ( $this->lastSection !== 'p' ) {
 351                                                                         $output .= $this->closeParagraph();
 352                                                                         $this->lastSection = '';
 353                                                                         $pendingPTag = '<p>';
 354                                                                 } else {
 355                                                                         $pendingPTag = '</p><p>';
 356                                                                 }
 357                                                         }
 358                                                 } else {
 359                                                         if ( $pendingPTag ) {
 360                                                                 $output .= $pendingPTag;
 361                                                                 $pendingPTag = false;
 362                                                                 $this->lastSection = 'p';
 363                                                         } elseif ( $this->lastSection !== 'p' ) {
 364                                                                 $output .= $this->closeParagraph() . '<p>';
 365                                                                 $this->lastSection = 'p';
 366                                                         }
 367                                                 }
 368                                         }
 369                                 }
 370                         }
 371                         # somewhere above we forget to get out of pre block (T2785)
 372                         if ( $preCloseMatch && $this->inPre ) {
 373                                 $this->inPre = false;
 374                         }
 375                         if ( $pendingPTag === false ) {
 376                                 if ( $prefixLength === 0 ) {
 377                                         $output .= $t;
 378                                         $output .= "\n";
 379                                 } else {
 380                                         // Trim whitespace in list items
 381                                         $output .= trim( $t );
 382                                 }
 383                         }
 384                 }
 385                 while ( $prefixLength ) {
 386                         $output .= $this->closeList( $prefix2[$prefixLength - 1] );
 387                         --$prefixLength;
 388                         if ( !$prefixLength ) {
 389                                 $output .= "\n";
 390                         }
 391                 }
 392                 if ( $this->lastSection !== '' ) {
 393                         $output .= '</' . $this->lastSection . '>';
 394                         $this->lastSection = '';
 395                 }
 396
 397                 return $output;
 398         }
 399
 400         /**
 401          * Split up a string on ':', ignoring any occurrences inside tags
 402          * to prevent illegal overlapping.
 403          *
 404          * @param string $str The string to split
 405          * @param string &$before Set to everything before the ':'
 406          * @param string &$after Set to everything after the ':'
 407          * @throws MWException
 408          * @return string The position of the ':', or false if none found
 409          */
 410         private function findColonNoLinks( $str, &$before, &$after ) {
 411                 if ( !preg_match( '/:|<|-\{/', $str, $m, PREG_OFFSET_CAPTURE ) ) {
 412                         # Nothing to find!
 413                         return false;
 414                 }
 415
 416                 if ( $m[0][0] === ':' ) {
 417                         # Easy; no tag nesting to worry about
 418                         $colonPos = $m[0][1];
 419                         $before = substr( $str, 0, $colonPos );
 420                         $after = substr( $str, $colonPos + 1 );
 421                         return $colonPos;
 422                 }
 423
 424                 # Ugly state machine to walk through avoiding tags.
 425                 $state = self::COLON_STATE_TEXT;
 426                 $ltLevel = 0;
 427                 $lcLevel = 0;
 428                 $len = strlen( $str );
 429                 for ( $i = $m[0][1]; $i < $len; $i++ ) {
 430                         $c = $str[$i];
 431
 432                         switch ( $state ) {
 433                                 case self::COLON_STATE_TEXT:
 434                                         switch ( $c ) {
 435                                                 case "<":
 436                                                         # Could be either a <start> tag or an </end> tag
 437                                                         $state = self::COLON_STATE_TAGSTART;
 438                                                         break;
 439                                                 case ":":
 440                                                         if ( $ltLevel === 0 ) {
 441                                                                 # We found it!
 442                                                                 $before = substr( $str, 0, $i );
 443                                                                 $after = substr( $str, $i + 1 );
 444                                                                 return $i;
 445                                                         }
 446                                                         # Embedded in a tag; don't break it.
 447                                                         break;
 448                                                 default:
 449                                                         # Skip ahead looking for something interesting
 450                                                         if ( !preg_match( '/:|<|-\{/', $str, $m, PREG_OFFSET_CAPTURE, $i ) ) {
 451                                                                 # Nothing else interesting
 452                                                                 return false;
 453                                                         }
 454                                                         if ( $m[0][0] === '-{' ) {
 455                                                                 $state = self::COLON_STATE_LC;
 456                                                                 $lcLevel++;
 457                                                                 $i = $m[0][1] + 1;
 458                                                         } else {
 459                                                                 # Skip ahead to next interesting character.
 460                                                                 $i = $m[0][1] - 1;
 461                                                         }
 462                                                         break;
 463                                         }
 464                                         break;
 465                                 case self::COLON_STATE_LC:
 466                                         # In language converter markup -{ ... }-
 467                                         if ( !preg_match( '/-\{|\}-/', $str, $m, PREG_OFFSET_CAPTURE, $i ) ) {
 468                                                 # Nothing else interesting to find; abort!
 469                                                 # We're nested in language converter markup, but there
 470                                                 # are no close tags left.  Abort!
 471                                                 break 2;
 472                                         } elseif ( $m[0][0] === '-{' ) {
 473                                                 $i = $m[0][1] + 1;
 474                                                 $lcLevel++;
 475                                         } elseif ( $m[0][0] === '}-' ) {
 476                                                 $i = $m[0][1] + 1;
 477                                                 $lcLevel--;
 478                                                 if ( $lcLevel === 0 ) {
 479                                                         $state = self::COLON_STATE_TEXT;
 480                                                 }
 481                                         }
 482                                         break;
 483                                 case self::COLON_STATE_TAG:
 484                                         # In a <tag>
 485                                         switch ( $c ) {
 486                                                 case ">":
 487                                                         $ltLevel++;
 488                                                         $state = self::COLON_STATE_TEXT;
 489                                                         break;
 490                                                 case "/":
 491                                                         # Slash may be followed by >?
 492                                                         $state = self::COLON_STATE_TAGSLASH;
 493                                                         break;
 494                                                 default:
 495                                                         # ignore
 496                                         }
 497                                         break;
 498                                 case self::COLON_STATE_TAGSTART:
 499                                         switch ( $c ) {
 500                                                 case "/":
 501                                                         $state = self::COLON_STATE_CLOSETAG;
 502                                                         break;
 503                                                 case "!":
 504                                                         $state = self::COLON_STATE_COMMENT;
 505                                                         break;
 506                                                 case ">":
 507                                                         # Illegal early close? This shouldn't happen D:
 508                                                         $state = self::COLON_STATE_TEXT;
 509                                                         break;
 510                                                 default:
 511                                                         $state = self::COLON_STATE_TAG;
 512                                         }
 513                                         break;
 514                                 case self::COLON_STATE_CLOSETAG:
 515                                         # In a </tag>
 516                                         if ( $c === ">" ) {
 517                                                 if ( $ltLevel > 0 ) {
 518                                                         $ltLevel--;
 519                                                 } else {
 520                                                         # ignore the excess close tag, but keep looking for
 521                                                         # colons. (This matches Parsoid behavior.)
 522                                                         wfDebug( __METHOD__ . ": Invalid input; too many close tags\n" );
 523                                                 }
 524                                                 $state = self::COLON_STATE_TEXT;
 525                                         }
 526                                         break;
 527                                 case self::COLON_STATE_TAGSLASH:
 528                                         if ( $c === ">" ) {
 529                                                 # Yes, a self-closed tag <blah/>
 530                                                 $state = self::COLON_STATE_TEXT;
 531                                         } else {
 532                                                 # Probably we're jumping the gun, and this is an attribute
 533                                                 $state = self::COLON_STATE_TAG;
 534                                         }
 535                                         break;
 536                                 case self::COLON_STATE_COMMENT:
 537                                         if ( $c === "-" ) {
 538                                                 $state = self::COLON_STATE_COMMENTDASH;
 539                                         }
 540                                         break;
 541                                 case self::COLON_STATE_COMMENTDASH:
 542                                         if ( $c === "-" ) {
 543                                                 $state = self::COLON_STATE_COMMENTDASHDASH;
 544                                         } else {
 545                                                 $state = self::COLON_STATE_COMMENT;
 546                                         }
 547                                         break;
 548                                 case self::COLON_STATE_COMMENTDASHDASH:
 549                                         if ( $c === ">" ) {
 550                                                 $state = self::COLON_STATE_TEXT;
 551                                         } else {
 552                                                 $state = self::COLON_STATE_COMMENT;
 553                                         }
 554                                         break;
 555                                 default:
 556                                         throw new MWException( "State machine error in " . __METHOD__ );
 557                         }
 558                 }
 559                 if ( $ltLevel > 0 || $lcLevel > 0 ) {
 560                         wfDebug(
 561                                 __METHOD__ . ": Invalid input; not enough close tags " .
 562                                 "(level $ltLevel/$lcLevel, state $state)\n"
 563                         );
 564                         return false;
 565                 }
 566                 return false;
 567         }
 568 }