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
  42         /**
  43          * Make lists from lines starting with ':', '*', '#', etc.
  44          *
  45          * @param string $text
  46          * @param bool $lineStart Whether or not this is at the start of a line.
  47          * @return string The lists rendered as HTML
  48          */
  49         public static function doBlockLevels( $text, $lineStart ) {
  50                 $pass = new self( $text, $lineStart );
  51                 return $pass->execute();
  52         }
  53
  54         /**
  55          * Private constructor
  56          */
  57         private function __construct( $text, $lineStart ) {
  58                 $this->text = $text;
  59                 $this->lineStart = $lineStart;
  60         }
  61
  62         /**
  63          * If a pre or p is open, return the corresponding close tag and update
  64          * the state. If no tag is open, return an empty string.
  65          * @return string
  66          */
  67         private function closeParagraph() {
  68                 $result = '';
  69                 if ( $this->lastSection !== '' ) {
  70                         $result = '</' . $this->lastSection . ">\n";
  71                 }
  72                 $this->inPre = false;
  73                 $this->lastSection = '';
  74                 return $result;
  75         }
  76
  77         /**
  78          * getCommon() returns the length of the longest common substring
  79          * of both arguments, starting at the beginning of both.
  80          *
  81          * @param string $st1
  82          * @param string $st2
  83          *
  84          * @return int
  85          */
  86         private function getCommon( $st1, $st2 ) {
  87                 $shorter = min( strlen( $st1 ), strlen( $st2 ) );
  88
  89                 for ( $i = 0; $i < $shorter; ++$i ) {
  90                         if ( $st1[$i] !== $st2[$i] ) {
  91                                 break;
  92                         }
  93                 }
  94                 return $i;
  95         }
  96
  97         /**
  98          * Open the list item element identified by the prefix character.
  99          *
 100          * @param string $char
 101          *
 102          * @return string
 103          */
 104         private function openList( $char ) {
 105                 $result = $this->closeParagraph();
 106
 107                 if ( '*' === $char ) {
 108                         $result .= "<ul><li>";
 109                 } elseif ( '#' === $char ) {
 110                         $result .= "<ol><li>";
 111                 } elseif ( ':' === $char ) {
 112                         $result .= "<dl><dd>";
 113                 } elseif ( ';' === $char ) {
 114                         $result .= "<dl><dt>";
 115                         $this->DTopen = true;
 116                 } else {
 117                         $result = '<!-- ERR 1 -->';
 118                 }
 119
 120                 return $result;
 121         }
 122
 123         /**
 124          * Close the current list item and open the next one.
 125          * @param string $char
 126          *
 127          * @return string
 128          */
 129         private function nextItem( $char ) {
 130                 if ( '*' === $char || '#' === $char ) {
 131                         return "</li>\n<li>";
 132                 } elseif ( ':' === $char || ';' === $char ) {
 133                         $close = "</dd>\n";
 134                         if ( $this->DTopen ) {
 135                                 $close = "</dt>\n";
 136                         }
 137                         if ( ';' === $char ) {
 138                                 $this->DTopen = true;
 139                                 return $close . '<dt>';
 140                         } else {
 141                                 $this->DTopen = false;
 142                                 return $close . '<dd>';
 143                         }
 144                 }
 145                 return '<!-- ERR 2 -->';
 146         }
 147
 148         /**
 149          * Close the current list item identified by the prefix character.
 150          * @param string $char
 151          *
 152          * @return string
 153          */
 154         private function closeList( $char ) {
 155                 if ( '*' === $char ) {
 156                         $text = "</li></ul>";
 157                 } elseif ( '#' === $char ) {
 158                         $text = "</li></ol>";
 159                 } elseif ( ':' === $char ) {
 160                         if ( $this->DTopen ) {
 161                                 $this->DTopen = false;
 162                                 $text = "</dt></dl>";
 163                         } else {
 164                                 $text = "</dd></dl>";
 165                         }
 166                 } else {
 167                         return '<!-- ERR 3 -->';
 168                 }
 169                 return $text;
 170         }
 171
 172         /**
 173          * Execute the pass.
 174          * @return string
 175          */
 176         private function execute() {
 177                 $text = $this->text;
 178                 # Parsing through the text line by line.  The main thing
 179                 # happening here is handling of block-level elements p, pre,
 180                 # and making lists from lines starting with * # : etc.
 181                 $textLines = StringUtils::explode( "\n", $text );
 182
 183                 $lastPrefix = $output = '';
 184                 $this->DTopen = $inBlockElem = false;
 185                 $prefixLength = 0;
 186                 $pendingPTag = false;
 187                 $inBlockquote = false;
 188
 189                 foreach ( $textLines as $inputLine ) {
 190                         # Fix up $lineStart
 191                         if ( !$this->lineStart ) {
 192                                 $output .= $inputLine;
 193                                 $this->lineStart = true;
 194                                 continue;
 195                         }
 196                         # * = ul
 197                         # # = ol
 198                         # ; = dt
 199                         # : = dd
 200
 201                         $lastPrefixLength = strlen( $lastPrefix );
 202                         $preCloseMatch = preg_match( '/<\\/pre/i', $inputLine );
 203                         $preOpenMatch = preg_match( '/<pre/i', $inputLine );
 204                         # If not in a <pre> element, scan for and figure out what prefixes are there.
 205                         if ( !$this->inPre ) {
 206                                 # Multiple prefixes may abut each other for nested lists.
 207                                 $prefixLength = strspn( $inputLine, '*#:;' );
 208                                 $prefix = substr( $inputLine, 0, $prefixLength );
 209
 210                                 # eh?
 211                                 # ; and : are both from definition-lists, so they're equivalent
 212                                 #  for the purposes of determining whether or not we need to open/close
 213                                 #  elements.
 214                                 $prefix2 = str_replace( ';', ':', $prefix );
 215                                 $t = substr( $inputLine, $prefixLength );
 216                                 $this->inPre = (bool)$preOpenMatch;
 217                         } else {
 218                                 # Don't interpret any other prefixes in preformatted text
 219                                 $prefixLength = 0;
 220                                 $prefix = $prefix2 = '';
 221                                 $t = $inputLine;
 222                         }
 223
 224                         # List generation
 225                         if ( $prefixLength && $lastPrefix === $prefix2 ) {
 226                                 # Same as the last item, so no need to deal with nesting or opening stuff
 227                                 $output .= $this->nextItem( substr( $prefix, -1 ) );
 228                                 $pendingPTag = false;
 229
 230                                 if ( substr( $prefix, -1 ) === ';' ) {
 231                                         # The one nasty exception: definition lists work like this:
 232                                         # ; title : definition text
 233                                         # So we check for : in the remainder text to split up the
 234                                         # title and definition, without b0rking links.
 235                                         $term = $t2 = '';
 236                                         if ( $this->findColonNoLinks( $t, $term, $t2 ) !== false ) {
 237                                                 $t = $t2;
 238                                                 $output .= $term . $this->nextItem( ':' );
 239                                         }
 240                                 }
 241                         } elseif ( $prefixLength || $lastPrefixLength ) {
 242                                 # We need to open or close prefixes, or both.
 243
 244                                 # Either open or close a level...
 245                                 $commonPrefixLength = $this->getCommon( $prefix, $lastPrefix );
 246                                 $pendingPTag = false;
 247
 248                                 # Close all the prefixes which aren't shared.
 249                                 while ( $commonPrefixLength < $lastPrefixLength ) {
 250                                         $output .= $this->closeList( $lastPrefix[$lastPrefixLength - 1] );
 251                                         --$lastPrefixLength;
 252                                 }
 253
 254                                 # Continue the current prefix if appropriate.
 255                                 if ( $prefixLength <= $commonPrefixLength && $commonPrefixLength > 0 ) {
 256                                         $output .= $this->nextItem( $prefix[$commonPrefixLength - 1] );
 257                                 }
 258
 259                                 # Open prefixes where appropriate.
 260                                 if ( $lastPrefix && $prefixLength > $commonPrefixLength ) {
 261                                         $output .= "\n";
 262                                 }
 263                                 while ( $prefixLength > $commonPrefixLength ) {
 264                                         $char = substr( $prefix, $commonPrefixLength, 1 );
 265                                         $output .= $this->openList( $char );
 266
 267                                         if ( ';' === $char ) {
 268                                                 # @todo FIXME: This is dupe of code above
 269                                                 if ( $this->findColonNoLinks( $t, $term, $t2 ) !== false ) {
 270                                                         $t = $t2;
 271                                                         $output .= $term . $this->nextItem( ':' );
 272                                                 }
 273                                         }
 274                                         ++$commonPrefixLength;
 275                                 }
 276                                 if ( !$prefixLength && $lastPrefix ) {
 277                                         $output .= "\n";
 278                                 }
 279                                 $lastPrefix = $prefix2;
 280                         }
 281
 282                         # If we have no prefixes, go to paragraph mode.
 283                         if ( 0 == $prefixLength ) {
 284                                 # No prefix (not in list)--go to paragraph mode
 285                                 # @todo consider using a stack for nestable elements like span, table and div
 286                                 $openMatch = preg_match(
 287                                         '/(?:<table|<h1|<h2|<h3|<h4|<h5|<h6|<pre|<tr|'
 288                                                 . '<p|<ul|<ol|<dl|<li|<\\/tr|<\\/td|<\\/th)/iS',
 289                                         $t
 290                                 );
 291                                 $closeMatch = preg_match(
 292                                         '/(?:<\\/table|<\\/h1|<\\/h2|<\\/h3|<\\/h4|<\\/h5|<\\/h6|'
 293                                                 . '<td|<th|<\\/?blockquote|<\\/?div|<hr|<\\/pre|<\\/p|<\\/mw:|'
 294                                                 . Parser::MARKER_PREFIX
 295                                                 . '-pre|<\\/li|<\\/ul|<\\/ol|<\\/dl|<\\/?center)/iS',
 296                                         $t
 297                                 );
 298
 299                                 if ( $openMatch || $closeMatch ) {
 300                                         $pendingPTag = false;
 301                                         # @todo bug 5718: paragraph closed
 302                                         $output .= $this->closeParagraph();
 303                                         if ( $preOpenMatch && !$preCloseMatch ) {
 304                                                 $this->inPre = true;
 305                                         }
 306                                         $bqOffset = 0;
 307                                         while ( preg_match( '/<(\\/?)blockquote[\s>]/i', $t,
 308                                                 $bqMatch, PREG_OFFSET_CAPTURE, $bqOffset )
 309                                         ) {
 310                                                 $inBlockquote = !$bqMatch[1][0]; // is this a close tag?
 311                                                 $bqOffset = $bqMatch[0][1] + strlen( $bqMatch[0][0] );
 312                                         }
 313                                         $inBlockElem = !$closeMatch;
 314                                 } elseif ( !$inBlockElem && !$this->inPre ) {
 315                                         if ( ' ' == substr( $t, 0, 1 )
 316                                                 && ( $this->lastSection === 'pre' || trim( $t ) != '' )
 317                                                 && !$inBlockquote
 318                                         ) {
 319                                                 # pre
 320                                                 if ( $this->lastSection !== 'pre' ) {
 321                                                         $pendingPTag = false;
 322                                                         $output .= $this->closeParagraph() . '<pre>';
 323                                                         $this->lastSection = 'pre';
 324                                                 }
 325                                                 $t = substr( $t, 1 );
 326                                         } else {
 327                                                 # paragraph
 328                                                 if ( trim( $t ) === '' ) {
 329                                                         if ( $pendingPTag ) {
 330                                                                 $output .= $pendingPTag . '<br />';
 331                                                                 $pendingPTag = false;
 332                                                                 $this->lastSection = 'p';
 333                                                         } else {
 334                                                                 if ( $this->lastSection !== 'p' ) {
 335                                                                         $output .= $this->closeParagraph();
 336                                                                         $this->lastSection = '';
 337                                                                         $pendingPTag = '<p>';
 338                                                                 } else {
 339                                                                         $pendingPTag = '</p><p>';
 340                                                                 }
 341                                                         }
 342                                                 } else {
 343                                                         if ( $pendingPTag ) {
 344                                                                 $output .= $pendingPTag;
 345                                                                 $pendingPTag = false;
 346                                                                 $this->lastSection = 'p';
 347                                                         } elseif ( $this->lastSection !== 'p' ) {
 348                                                                 $output .= $this->closeParagraph() . '<p>';
 349                                                                 $this->lastSection = 'p';
 350                                                         }
 351                                                 }
 352                                         }
 353                                 }
 354                         }
 355                         # somewhere above we forget to get out of pre block (bug 785)
 356                         if ( $preCloseMatch && $this->inPre ) {
 357                                 $this->inPre = false;
 358                         }
 359                         if ( $pendingPTag === false ) {
 360                                 $output .= $t;
 361                                 if ( $prefixLength === 0 ) {
 362                                         $output .= "\n";
 363                                 }
 364                         }
 365                 }
 366                 while ( $prefixLength ) {
 367                         $output .= $this->closeList( $prefix2[$prefixLength - 1] );
 368                         --$prefixLength;
 369                         if ( !$prefixLength ) {
 370                                 $output .= "\n";
 371                         }
 372                 }
 373                 if ( $this->lastSection !== '' ) {
 374                         $output .= '</' . $this->lastSection . '>';
 375                         $this->lastSection = '';
 376                 }
 377
 378                 return $output;
 379         }
 380
 381         /**
 382          * Split up a string on ':', ignoring any occurrences inside tags
 383          * to prevent illegal overlapping.
 384          *
 385          * @param string $str The string to split
 386          * @param string &$before Set to everything before the ':'
 387          * @param string &$after Set to everything after the ':'
 388          * @throws MWException
 389          * @return string The position of the ':', or false if none found
 390          */
 391         private function findColonNoLinks( $str, &$before, &$after ) {
 392                 $colonPos = strpos( $str, ':' );
 393                 if ( $colonPos === false ) {
 394                         # Nothing to find!
 395                         return false;
 396                 }
 397
 398                 $ltPos = strpos( $str, '<' );
 399                 if ( $ltPos === false || $ltPos > $colonPos ) {
 400                         # Easy; no tag nesting to worry about
 401                         $before = substr( $str, 0, $colonPos );
 402                         $after = substr( $str, $colonPos + 1 );
 403                         return $colonPos;
 404                 }
 405
 406                 # Ugly state machine to walk through avoiding tags.
 407                 $state = self::COLON_STATE_TEXT;
 408                 $level = 0;
 409                 $len = strlen( $str );
 410                 for ( $i = 0; $i < $len; $i++ ) {
 411                         $c = $str[$i];
 412
 413                         switch ( $state ) {
 414                         case self::COLON_STATE_TEXT:
 415                                 switch ( $c ) {
 416                                 case "<":
 417                                         # Could be either a <start> tag or an </end> tag
 418                                         $state = self::COLON_STATE_TAGSTART;
 419                                         break;
 420                                 case ":":
 421                                         if ( $level === 0 ) {
 422                                                 # We found it!
 423                                                 $before = substr( $str, 0, $i );
 424                                                 $after = substr( $str, $i + 1 );
 425                                                 return $i;
 426                                         }
 427                                         # Embedded in a tag; don't break it.
 428                                         break;
 429                                 default:
 430                                         # Skip ahead looking for something interesting
 431                                         $colonPos = strpos( $str, ':', $i );
 432                                         if ( $colonPos === false ) {
 433                                                 # Nothing else interesting
 434                                                 return false;
 435                                         }
 436                                         $ltPos = strpos( $str, '<', $i );
 437                                         if ( $level === 0 ) {
 438                                                 if ( $ltPos === false || $colonPos < $ltPos ) {
 439                                                         # We found it!
 440                                                         $before = substr( $str, 0, $colonPos );
 441                                                         $after = substr( $str, $colonPos + 1 );
 442                                                         return $i;
 443                                                 }
 444                                         }
 445                                         if ( $ltPos === false ) {
 446                                                 # Nothing else interesting to find; abort!
 447                                                 # We're nested, but there's no close tags left. Abort!
 448                                                 break 2;
 449                                         }
 450                                         # Skip ahead to next tag start
 451                                         $i = $ltPos;
 452                                         $state = self::COLON_STATE_TAGSTART;
 453                                 }
 454                                 break;
 455                         case self::COLON_STATE_TAG:
 456                                 # In a <tag>
 457                                 switch ( $c ) {
 458                                 case ">":
 459                                         $level++;
 460                                         $state = self::COLON_STATE_TEXT;
 461                                         break;
 462                                 case "/":
 463                                         # Slash may be followed by >?
 464                                         $state = self::COLON_STATE_TAGSLASH;
 465                                         break;
 466                                 default:
 467                                         # ignore
 468                                 }
 469                                 break;
 470                         case self::COLON_STATE_TAGSTART:
 471                                 switch ( $c ) {
 472                                 case "/":
 473                                         $state = self::COLON_STATE_CLOSETAG;
 474                                         break;
 475                                 case "!":
 476                                         $state = self::COLON_STATE_COMMENT;
 477                                         break;
 478                                 case ">":
 479                                         # Illegal early close? This shouldn't happen D:
 480                                         $state = self::COLON_STATE_TEXT;
 481                                         break;
 482                                 default:
 483                                         $state = self::COLON_STATE_TAG;
 484                                 }
 485                                 break;
 486                         case self::COLON_STATE_CLOSETAG:
 487                                 # In a </tag>
 488                                 if ( $c === ">" ) {
 489                                         $level--;
 490                                         if ( $level < 0 ) {
 491                                                 wfDebug( __METHOD__ . ": Invalid input; too many close tags\n" );
 492                                                 return false;
 493                                         }
 494                                         $state = self::COLON_STATE_TEXT;
 495                                 }
 496                                 break;
 497                         case self::COLON_STATE_TAGSLASH:
 498                                 if ( $c === ">" ) {
 499                                         # Yes, a self-closed tag <blah/>
 500                                         $state = self::COLON_STATE_TEXT;
 501                                 } else {
 502                                         # Probably we're jumping the gun, and this is an attribute
 503                                         $state = self::COLON_STATE_TAG;
 504                                 }
 505                                 break;
 506                         case self::COLON_STATE_COMMENT:
 507                                 if ( $c === "-" ) {
 508                                         $state = self::COLON_STATE_COMMENTDASH;
 509                                 }
 510                                 break;
 511                         case self::COLON_STATE_COMMENTDASH:
 512                                 if ( $c === "-" ) {
 513                                         $state = self::COLON_STATE_COMMENTDASHDASH;
 514                                 } else {
 515                                         $state = self::COLON_STATE_COMMENT;
 516                                 }
 517                                 break;
 518                         case self::COLON_STATE_COMMENTDASHDASH:
 519                                 if ( $c === ">" ) {
 520                                         $state = self::COLON_STATE_TEXT;
 521                                 } else {
 522                                         $state = self::COLON_STATE_COMMENT;
 523                                 }
 524                                 break;
 525                         default:
 526                                 throw new MWException( "State machine error in " . __METHOD__ );
 527                         }
 528                 }
 529                 if ( $level > 0 ) {
 530                         wfDebug( __METHOD__ . ": Invalid input; not enough close tags (level $level, state $state)\n" );
 531                         return false;
 532                 }
 533                 return false;
 534         }
 535 }