includes/DifferenceEngine.php

   1 <?php
   2 /**
   3  * See diff.doc
   4  * @package MediaWiki
   5  * @subpackage DifferenceEngine
   6  */
   7
   8 /** */
   9 require_once( 'Revision.php' );
  10
  11 /**
  12  * @todo document
  13  * @access public
  14  * @package MediaWiki
  15  * @subpackage DifferenceEngine
  16  */
  17 class DifferenceEngine {
  18         /**#@+
  19          * @access private
  20          */
  21         var $mOldid, $mNewid;
  22         var $mOldtitle, $mNewtitle, $mPagetitle;
  23         var $mOldtext, $mNewtext;
  24         var $mOldUser, $mNewUser;
  25         var $mOldComment, $mNewComment;
  26         var $mOldPage, $mNewPage;
  27         var $mRcidMarkPatrolled;
  28         /**#@-*/
  29
  30         /**
  31          * Constructor
  32          * @param integer $old Old ID we want to show and diff with.
  33          * @param string $new Either 'prev' or 'next'.
  34          * @param integer $rcid ??? (default 0)
  35          */
  36         function DifferenceEngine( $old, $new, $rcid = 0 ) {
  37                 global $wgTitle;
  38
  39                 if ( 'prev' == $new ) {
  40                         # Show diff between revision $old and the previous one.
  41                         # Get previous one from DB.
  42                         #
  43                         $this->mNewid = intval($old);
  44
  45                         $this->mOldid = $wgTitle->getPreviousRevisionID( $this->mNewid );
  46
  47                 } elseif ( 'next' == $new ) {
  48                         # Show diff between revision $old and the previous one.
  49                         # Get previous one from DB.
  50                         #
  51                         $this->mOldid = intval($old);
  52                         $this->mNewid = $wgTitle->getNextRevisionID( $this->mOldid );
  53                         if ( false === $this->mNewid ) {
  54                                 # if no result, NewId points to the newest old revision. The only newer
  55                                 # revision is cur, which is "0".
  56                                 $this->mNewid = 0;
  57                         }
  58
  59                 } else {
  60                         $this->mOldid = intval($old);
  61                         $this->mNewid = intval($new);
  62                 }
  63                 $this->mRcidMarkPatrolled = intval($rcid);  # force it to be an integer
  64         }
  65
  66         function showDiffPage() {
  67                 global $wgUser, $wgTitle, $wgOut, $wgContLang, $wgOnlySysopsCanPatrol,
  68                        $wgUseExternalEditor, $wgUseRCPatrol;
  69                 $fname = 'DifferenceEngine::showDiffPage';
  70                 wfProfileIn( $fname );
  71
  72                 # If external diffs are enabled both globally and for the user,
  73                 # we'll use the application/x-external-editor interface to call
  74                 # an external diff tool like kompare, kdiff3, etc.
  75                 if($wgUseExternalEditor && $wgUser->getOption('externaldiff')) {
  76                         global $wgInputEncoding,$wgServer,$wgScript,$wgLang;
  77                         $wgOut->disable();
  78                         header ( "Content-type: application/x-external-editor; charset=".$wgInputEncoding );
  79                         $url1=$wgTitle->getFullURL("action=raw&oldid=".$this->mOldid);
  80                         $url2=$wgTitle->getFullURL("action=raw&oldid=".$this->mNewid);
  81                         $special=$wgLang->getNsText(NS_SPECIAL);
  82                         $control=<<<CONTROL
  83 [Process]
  84 Type=Diff text
  85 Engine=MediaWiki
  86 Script={$wgServer}{$wgScript}
  87 Special namespace={$special}
  88
  89 [File]
  90 Extension=wiki
  91 URL=$url1
  92
  93 [File 2]
  94 Extension=wiki
  95 URL=$url2
  96 CONTROL;
  97                         echo($control);
  98                         return;
  99                 }
 100
 101                 # mOldid is false if the difference engine is called with a "vague" query for
 102                 # a diff between a version V and its previous version V' AND the version V
 103                 # is the first version of that article. In that case, V' does not exist.
 104                 if ( $this->mOldid === false ) {
 105                         $this->showFirstRevision();
 106                         wfProfileOut( $fname );
 107                         return;
 108                 }
 109
 110                 $t = $wgTitle->getPrefixedText() . " (Diff: {$this->mOldid}, " .
 111                   "{$this->mNewid})";
 112                 $mtext = wfMsg( 'missingarticle', $t );
 113
 114                 $wgOut->setArticleFlag( false );
 115                 if ( ! $this->loadText() ) {
 116                         $wgOut->setPagetitle( wfMsg( 'errorpagetitle' ) );
 117                         $wgOut->addHTML( $mtext );
 118                         wfProfileOut( $fname );
 119                         return;
 120                 }
 121                 $wgOut->suppressQuickbar();
 122
 123                 $oldTitle = $this->mOldPage->getPrefixedText();
 124                 $newTitle = $this->mNewPage->getPrefixedText();
 125                 if( $oldTitle == $newTitle ) {
 126                         $wgOut->setPageTitle( $newTitle );
 127                 } else {
 128                         $wgOut->setPageTitle( $oldTitle . ', ' . $newTitle );
 129                 }
 130                 $wgOut->setSubtitle( wfMsg( 'difference' ) );
 131                 $wgOut->setRobotpolicy( 'noindex,follow' );
 132
 133                 if ( !( $this->mOldPage->userCanRead() && $this->mNewPage->userCanRead() ) ) {
 134                         $wgOut->loginToUse();
 135                         $wgOut->output();
 136                         wfProfileOut( $fname );
 137                         exit;
 138                 }
 139
 140                 $sk = $wgUser->getSkin();
 141                 $talk = $wgContLang->getNsText( NS_TALK );
 142                 $contribs = wfMsg( 'contribslink' );
 143
 144                 $this->mOldComment = $sk->formatComment($this->mOldComment);
 145                 $this->mNewComment = $sk->formatComment($this->mNewComment);
 146
 147                 $oldUserLink = $sk->makeLinkObj( Title::makeTitleSafe( NS_USER, $this->mOldUser ), $this->mOldUser );
 148                 $newUserLink = $sk->makeLinkObj( Title::makeTitleSafe( NS_USER, $this->mNewUser ), $this->mNewUser );
 149                 $oldUTLink = $sk->makeLinkObj( Title::makeTitleSafe( NS_USER_TALK, $this->mOldUser ), $talk );
 150                 $newUTLink = $sk->makeLinkObj( Title::makeTitleSafe( NS_USER_TALK, $this->mNewUser ), $talk );
 151                 $oldContribs = $sk->makeKnownLinkObj( Title::makeTitle( NS_SPECIAL, 'Contributions' ), $contribs,
 152                         'target=' . urlencode($this->mOldUser) );
 153                 $newContribs = $sk->makeKnownLinkObj( Title::makeTitle( NS_SPECIAL, 'Contributions' ), $contribs,
 154                         'target=' . urlencode($this->mNewUser) );
 155                 if ( $this->newRev->isCurrent() && $wgUser->isAllowed('rollback') ) {
 156                         $rollback = '&nbsp;&nbsp;&nbsp;<strong>[' . $sk->makeKnownLinkObj( $wgTitle, wfMsg( 'rollbacklink' ),
 157                                 'action=rollback&from=' . urlencode($this->mNewUser) .
 158                                 '&token=' . urlencode( $wgUser->editToken( array( $wgTitle->getPrefixedText(), $this->mNewUser ) ) ) ) .
 159                                 ']</strong>';
 160                 } else {
 161                         $rollback = '';
 162                 }
 163                 if ( $wgUseRCPatrol && $this->mRcidMarkPatrolled != 0 && $wgUser->isLoggedIn() &&
 164                      ( $wgUser->isAllowed('rollback') || !$wgOnlySysopsCanPatrol ) )
 165                 {
 166                         $patrol = ' [' . $sk->makeKnownLinkObj( $wgTitle, wfMsg( 'markaspatrolleddiff' ),
 167                                 "action=markpatrolled&rcid={$this->mRcidMarkPatrolled}" ) . ']';
 168                 } else {
 169                         $patrol = '';
 170                 }
 171
 172                 $prevlink = $sk->makeKnownLinkObj( $wgTitle, wfMsg( 'previousdiff' ), 'diff=prev&oldid='.$this->mOldid );
 173                 if ( $this->mNewid == 0 ) {
 174                         $nextlink = '';
 175                 } else {
 176                         $nextlink = $sk->makeKnownLinkObj( $wgTitle, wfMsg( 'nextdiff' ), 'diff=next&oldid='.$this->mNewid );
 177                 }
 178
 179                 $oldHeader = "<strong>{$this->mOldtitle}</strong><br />$oldUserLink " .
 180                         "($oldUTLink | $oldContribs)<br />" . $this->mOldComment .
 181                         '<br />' . $prevlink;
 182                 $newHeader = "<strong>{$this->mNewtitle}</strong><br />$newUserLink " .
 183                         "($newUTLink | $newContribs) $rollback<br />" . $this->mNewComment .
 184                         '<br />' . $nextlink . $patrol;
 185
 186                 DifferenceEngine::showDiff( $this->mOldtext, $this->mNewtext,
 187                   $oldHeader, $newHeader );
 188                 $wgOut->addHTML( "<hr /><h2>{$this->mPagetitle}</h2>\n" );
 189                 $wgOut->addWikiText( $this->mNewtext );
 190
 191                 wfProfileOut( $fname );
 192         }
 193
 194         /**
 195          * Show the first revision of an article. Uses normal diff headers in
 196          * contrast to normal "old revision" display style.
 197          */
 198         function showFirstRevision() {
 199                 global $wgOut, $wgTitle, $wgUser, $wgLang;
 200
 201                 $fname = 'DifferenceEngine::showFirstRevision';
 202                 wfProfileIn( $fname );
 203
 204
 205                 $this->mOldid = $this->mNewid; # hack to make loadText() work.
 206
 207                 # Get article text from the DB
 208                 #
 209                 if ( ! $this->loadText() ) {
 210                         $t = $wgTitle->getPrefixedText() . " (Diff: {$this->mOldid}, " .
 211                           "{$this->mNewid})";
 212                         $mtext = wfMsg( 'missingarticle', $t );
 213                         $wgOut->setPagetitle( wfMsg( 'errorpagetitle' ) );
 214                         $wgOut->addHTML( $mtext );
 215                         wfProfileOut( $fname );
 216                         return;
 217                 }
 218
 219                 # Check if user is allowed to look at this page. If not, bail out.
 220                 #
 221                 if ( !( $this->mOldPage->userCanRead() ) ) {
 222                         $wgOut->loginToUse();
 223                         $wgOut->output();
 224                         wfProfileOut( $fname );
 225                         exit;
 226                 }
 227
 228                 # Prepare the header box
 229                 #
 230                 $sk = $wgUser->getSkin();
 231
 232                 $uTLink = $sk->makeLinkObj( Title::makeTitleSafe( NS_USER_TALK, $this->mOldUser ),  $wgLang->getNsText( NS_TALK ) );
 233                 $userLink = $sk->makeLinkObj( Title::makeTitleSafe( NS_USER, $this->mOldUser ), $this->mOldUser );
 234                 $contribs = $sk->makeKnownLinkObj( Title::makeTitle( NS_SPECIAL, 'Contributions' ), wfMsg( 'contribslink' ),
 235                         'target=' . urlencode($this->mOldUser) );
 236                 $nextlink = $sk->makeKnownLinkObj( $wgTitle, wfMsg( 'nextdiff' ), 'diff=next&oldid='.$this->mNewid );
 237                 $header = "<div class=\"firstrevisionheader\" style=\"text-align: center\"><strong>{$this->mOldtitle}</strong><br />$userLink " .
 238                         "($uTLink | $contribs)<br />" . $this->mOldComment .
 239                         '<br />' . $nextlink. "</div>\n";
 240
 241                 $wgOut->addHTML( $header );
 242
 243                 $wgOut->setSubtitle( wfMsg( 'difference' ) );
 244                 $wgOut->setRobotpolicy( 'noindex,follow' );
 245
 246
 247                 # Show current revision
 248                 #
 249                 $wgOut->addHTML( "<hr /><h2>{$this->mPagetitle}</h2>\n" );
 250                 $wgOut->addWikiText( $this->mNewtext );
 251
 252                 wfProfileOut( $fname );
 253         }
 254
 255         function showDiff( $otext, $ntext, $otitle, $ntitle ) {
 256                 global $wgOut;
 257                 $wgOut->addHTML( DifferenceEngine::getDiff( $otext, $ntext, $otitle, $ntitle ) );
 258         }
 259
 260         function getDiff( $otext, $ntext, $otitle, $ntitle ) {
 261                 global $wgUseExternalDiffEngine, $wgContLang;
 262                 $out = "
 263                         <table border='0' width='98%' cellpadding='0' cellspacing='4' class='diff'>
 264                         <tr>
 265                                 <td colspan='2' width='50%' align='center' class='diff-otitle'>{$otitle}</td>
 266                                 <td colspan='2' width='50%' align='center' class='diff-ntitle'>{$ntitle}</td>
 267                         </tr>
 268                 ";
 269                 $otext = $wgContLang->segmentForDiff($otext);
 270                 $ntext = $wgContLang->segmentForDiff($ntext);
 271                 $difftext='';
 272                 if ( $wgUseExternalDiffEngine ) {
 273                         # For historical reasons, external diff engine expects
 274                         # input text to be HTML-escaped already
 275                         $otext = str_replace( "\r\n", "\n", htmlspecialchars ( $otext ) );
 276                         $ntext = str_replace( "\r\n", "\n", htmlspecialchars ( $ntext ) );
 277                         if( !function_exists( 'wikidiff_do_diff' ) ) {
 278                                 dl('php_wikidiff.so');
 279                         }
 280                         $difftext = wikidiff_do_diff( $otext, $ntext, 2 );
 281                 } else {
 282                         $ota = explode( "\n", str_replace( "\r\n", "\n", $otext ) );
 283                         $nta = explode( "\n", str_replace( "\r\n", "\n", $ntext ) );
 284                         $diffs =& new Diff( $ota, $nta );
 285                         $formatter =& new TableDiffFormatter();
 286                         $difftext = $formatter->format( $diffs );
 287                 }
 288                 $difftext = $wgContLang->unsegmentForDiff($difftext);
 289                 $out .= $difftext."</table>\n";
 290                 return $out;
 291         }
 292
 293         /**
 294          * Load the text of the articles to compare.  If newid is 0, then compare
 295          * the old article in oldid to the current article; if oldid is 0, then
 296          * compare the current article to the immediately previous one (ignoring the
 297          * value of newid).
 298          */
 299         function loadText() {
 300                 global $wgTitle, $wgOut, $wgLang;
 301                 $fname = 'DifferenceEngine::loadText';
 302
 303                 $dbr =& wfGetDB( DB_SLAVE );
 304                 if( $this->mNewid ) {
 305                         $this->newRev =& Revision::newFromId( $this->mNewid );
 306                 } else {
 307                         $this->newRev =& Revision::newFromTitle( $wgTitle );
 308                 }
 309                 if( is_null( $this->newRev ) ) {
 310                         return false;
 311                 }
 312
 313                 if( $this->newRev->isCurrent() ) {
 314                         $this->mPagetitle = htmlspecialchars( wfMsg( 'currentrev' ) );
 315                         $this->mNewPage = $wgTitle;
 316                         $newLink = $this->mNewPage->escapeLocalUrl();
 317                         $this->mNewtitle = "<a href='$newLink'>{$this->mPagetitle}</a>";
 318                 } else {
 319                         $this->mNewPage = $this->newRev->getTitle();
 320                         $newLink = $this->mNewPage->escapeLocalUrl ('oldid=' . $this->mNewid );
 321                         $t = $wgLang->timeanddate( $this->newRev->getTimestamp(), true );
 322                         $this->mPagetitle = htmlspecialchars( wfMsg( 'revisionasof', $t ) );
 323                         $this->mNewtitle = "<a href='$newLink'>{$this->mPagetitle}</a>";
 324                 }
 325
 326                 if( $this->mOldid ) {
 327                         $this->oldRev =& Revision::newFromId( $this->mOldid );
 328                 } else {
 329                         $this->oldRev =& $this->newRev->getPrevious();
 330                         $this->mOldid = $this->oldRev->getId();
 331                 }
 332                 if( is_null( $this->oldRev ) ) {
 333                         return false;
 334                 }
 335
 336                 $this->mOldPage = $this->oldRev->getTitle();
 337
 338                 $t = $wgLang->timeanddate( $this->oldRev->getTimestamp(), true );
 339                 $oldLink = $this->mOldPage->escapeLocalUrl( 'oldid=' . $this->mOldid );
 340                 $this->mOldtitle = "<a href='$oldLink'>" . htmlspecialchars( wfMsg( 'revisionasof', $t ) ) . '</a>';
 341
 342                 $this->mNewUser = $this->newRev->getUserText();
 343                 $this->mNewComment = $this->newRev->getComment();
 344                 $this->mNewtext = $this->newRev->getText();
 345
 346                 $this->mOldUser = $this->oldRev->getUserText();
 347                 $this->mOldComment = $this->oldRev->getComment();
 348                 $this->mOldtext = $this->oldRev->getText();
 349
 350                 return true;
 351         }
 352 }
 353
 354 // A PHP diff engine for phpwiki. (Taken from phpwiki-1.3.3)
 355 //
 356 // Copyright (C) 2000, 2001 Geoffrey T. Dairiki <dairiki@dairiki.org>
 357 // You may copy this code freely under the conditions of the GPL.
 358 //
 359
 360 define('USE_ASSERTS', function_exists('assert'));
 361
 362 /**
 363  * @todo document
 364  * @access private
 365  * @package MediaWiki
 366  * @subpackage DifferenceEngine
 367  */
 368 class _DiffOp {
 369         var $type;
 370         var $orig;
 371         var $closing;
 372
 373         function reverse() {
 374                 trigger_error('pure virtual', E_USER_ERROR);
 375         }
 376
 377         function norig() {
 378                 return $this->orig ? sizeof($this->orig) : 0;
 379         }
 380
 381         function nclosing() {
 382                 return $this->closing ? sizeof($this->closing) : 0;
 383         }
 384 }
 385
 386 /**
 387  * @todo document
 388  * @access private
 389  * @package MediaWiki
 390  * @subpackage DifferenceEngine
 391  */
 392 class _DiffOp_Copy extends _DiffOp {
 393         var $type = 'copy';
 394
 395         function _DiffOp_Copy ($orig, $closing = false) {
 396                 if (!is_array($closing))
 397                         $closing = $orig;
 398                 $this->orig = $orig;
 399                 $this->closing = $closing;
 400         }
 401
 402         function reverse() {
 403                 return new _DiffOp_Copy($this->closing, $this->orig);
 404         }
 405 }
 406
 407 /**
 408  * @todo document
 409  * @access private
 410  * @package MediaWiki
 411  * @subpackage DifferenceEngine
 412  */
 413 class _DiffOp_Delete extends _DiffOp {
 414         var $type = 'delete';
 415
 416         function _DiffOp_Delete ($lines) {
 417                 $this->orig = $lines;
 418                 $this->closing = false;
 419         }
 420
 421         function reverse() {
 422                 return new _DiffOp_Add($this->orig);
 423         }
 424 }
 425
 426 /**
 427  * @todo document
 428  * @access private
 429  * @package MediaWiki
 430  * @subpackage DifferenceEngine
 431  */
 432 class _DiffOp_Add extends _DiffOp {
 433         var $type = 'add';
 434
 435         function _DiffOp_Add ($lines) {
 436                 $this->closing = $lines;
 437                 $this->orig = false;
 438         }
 439
 440         function reverse() {
 441                 return new _DiffOp_Delete($this->closing);
 442         }
 443 }
 444
 445 /**
 446  * @todo document
 447  * @access private
 448  * @package MediaWiki
 449  * @subpackage DifferenceEngine
 450  */
 451 class _DiffOp_Change extends _DiffOp {
 452         var $type = 'change';
 453
 454         function _DiffOp_Change ($orig, $closing) {
 455                 $this->orig = $orig;
 456                 $this->closing = $closing;
 457         }
 458
 459         function reverse() {
 460                 return new _DiffOp_Change($this->closing, $this->orig);
 461         }
 462 }
 463
 464
 465 /**
 466  * Class used internally by Diff to actually compute the diffs.
 467  *
 468  * The algorithm used here is mostly lifted from the perl module
 469  * Algorithm::Diff (version 1.06) by Ned Konz, which is available at:
 470  *       http://www.perl.com/CPAN/authors/id/N/NE/NEDKONZ/Algorithm-Diff-1.06.zip
 471  *
 472  * More ideas are taken from:
 473  *       http://www.ics.uci.edu/~eppstein/161/960229.html
 474  *
 475  * Some ideas are (and a bit of code) are from from analyze.c, from GNU
 476  * diffutils-2.7, which can be found at:
 477  *       ftp://gnudist.gnu.org/pub/gnu/diffutils/diffutils-2.7.tar.gz
 478  *
 479  * closingly, some ideas (subdivision by NCHUNKS > 2, and some optimizations)
 480  * are my own.
 481  *
 482  * @author Geoffrey T. Dairiki
 483  * @access private
 484  * @package MediaWiki
 485  * @subpackage DifferenceEngine
 486  */
 487 class _DiffEngine
 488 {
 489         function diff ($from_lines, $to_lines) {
 490                 $fname = '_DiffEngine::diff';
 491                 wfProfileIn( $fname );
 492
 493                 $n_from = sizeof($from_lines);
 494                 $n_to = sizeof($to_lines);
 495
 496                 $this->xchanged = $this->ychanged = array();
 497                 $this->xv = $this->yv = array();
 498                 $this->xind = $this->yind = array();
 499                 unset($this->seq);
 500                 unset($this->in_seq);
 501                 unset($this->lcs);
 502
 503                 // Skip leading common lines.
 504                 for ($skip = 0; $skip < $n_from && $skip < $n_to; $skip++) {
 505                         if ($from_lines[$skip] != $to_lines[$skip])
 506                                 break;
 507                         $this->xchanged[$skip] = $this->ychanged[$skip] = false;
 508                 }
 509                 // Skip trailing common lines.
 510                 $xi = $n_from; $yi = $n_to;
 511                 for ($endskip = 0; --$xi > $skip && --$yi > $skip; $endskip++) {
 512                         if ($from_lines[$xi] != $to_lines[$yi])
 513                                 break;
 514                         $this->xchanged[$xi] = $this->ychanged[$yi] = false;
 515                 }
 516
 517                 // Ignore lines which do not exist in both files.
 518                 for ($xi = $skip; $xi < $n_from - $endskip; $xi++)
 519                         $xhash[$from_lines[$xi]] = 1;
 520                 for ($yi = $skip; $yi < $n_to - $endskip; $yi++) {
 521                         $line = $to_lines[$yi];
 522                         if ( ($this->ychanged[$yi] = empty($xhash[$line])) )
 523                                 continue;
 524                         $yhash[$line] = 1;
 525                         $this->yv[] = $line;
 526                         $this->yind[] = $yi;
 527                 }
 528                 for ($xi = $skip; $xi < $n_from - $endskip; $xi++) {
 529                         $line = $from_lines[$xi];
 530                         if ( ($this->xchanged[$xi] = empty($yhash[$line])) )
 531                                 continue;
 532                         $this->xv[] = $line;
 533                         $this->xind[] = $xi;
 534                 }
 535
 536                 // Find the LCS.
 537                 $this->_compareseq(0, sizeof($this->xv), 0, sizeof($this->yv));
 538
 539                 // Merge edits when possible
 540                 $this->_shift_boundaries($from_lines, $this->xchanged, $this->ychanged);
 541                 $this->_shift_boundaries($to_lines, $this->ychanged, $this->xchanged);
 542
 543                 // Compute the edit operations.
 544                 $edits = array();
 545                 $xi = $yi = 0;
 546                 while ($xi < $n_from || $yi < $n_to) {
 547                         USE_ASSERTS && assert($yi < $n_to || $this->xchanged[$xi]);
 548                         USE_ASSERTS && assert($xi < $n_from || $this->ychanged[$yi]);
 549
 550                         // Skip matching "snake".
 551                         $copy = array();
 552                         while ( $xi < $n_from && $yi < $n_to
 553                                         && !$this->xchanged[$xi] && !$this->ychanged[$yi]) {
 554                                 $copy[] = $from_lines[$xi++];
 555                                 ++$yi;
 556                         }
 557                         if ($copy)
 558                                 $edits[] = new _DiffOp_Copy($copy);
 559
 560                         // Find deletes & adds.
 561                         $delete = array();
 562                         while ($xi < $n_from && $this->xchanged[$xi])
 563                                 $delete[] = $from_lines[$xi++];
 564
 565                         $add = array();
 566                         while ($yi < $n_to && $this->ychanged[$yi])
 567                                 $add[] = $to_lines[$yi++];
 568
 569                         if ($delete && $add)
 570                                 $edits[] = new _DiffOp_Change($delete, $add);
 571                         elseif ($delete)
 572                                 $edits[] = new _DiffOp_Delete($delete);
 573                         elseif ($add)
 574                                 $edits[] = new _DiffOp_Add($add);
 575                 }
 576                 wfProfileOut( $fname );
 577                 return $edits;
 578         }
 579
 580
 581         /* Divide the Largest Common Subsequence (LCS) of the sequences
 582          * [XOFF, XLIM) and [YOFF, YLIM) into NCHUNKS approximately equally
 583          * sized segments.
 584          *
 585          * Returns (LCS, PTS).  LCS is the length of the LCS. PTS is an
 586          * array of NCHUNKS+1 (X, Y) indexes giving the diving points between
 587          * sub sequences.  The first sub-sequence is contained in [X0, X1),
 588          * [Y0, Y1), the second in [X1, X2), [Y1, Y2) and so on.  Note
 589          * that (X0, Y0) == (XOFF, YOFF) and
 590          * (X[NCHUNKS], Y[NCHUNKS]) == (XLIM, YLIM).
 591          *
 592          * This function assumes that the first lines of the specified portions
 593          * of the two files do not match, and likewise that the last lines do not
 594          * match.  The caller must trim matching lines from the beginning and end
 595          * of the portions it is going to specify.
 596          */
 597         function _diag ($xoff, $xlim, $yoff, $ylim, $nchunks) {
 598                 $fname = '_DiffEngine::_diag';
 599                 wfProfileIn( $fname );
 600                 $flip = false;
 601
 602                 if ($xlim - $xoff > $ylim - $yoff) {
 603                         // Things seems faster (I'm not sure I understand why)
 604                                 // when the shortest sequence in X.
 605                                 $flip = true;
 606                         list ($xoff, $xlim, $yoff, $ylim)
 607                         = array( $yoff, $ylim, $xoff, $xlim);
 608                 }
 609
 610                 if ($flip)
 611                         for ($i = $ylim - 1; $i >= $yoff; $i--)
 612                                 $ymatches[$this->xv[$i]][] = $i;
 613                 else
 614                         for ($i = $ylim - 1; $i >= $yoff; $i--)
 615                                 $ymatches[$this->yv[$i]][] = $i;
 616
 617                 $this->lcs = 0;
 618                 $this->seq[0]= $yoff - 1;
 619                 $this->in_seq = array();
 620                 $ymids[0] = array();
 621
 622                 $numer = $xlim - $xoff + $nchunks - 1;
 623                 $x = $xoff;
 624                 for ($chunk = 0; $chunk < $nchunks; $chunk++) {
 625                         wfProfileIn( "$fname-chunk" );
 626                         if ($chunk > 0)
 627                                 for ($i = 0; $i <= $this->lcs; $i++)
 628                                         $ymids[$i][$chunk-1] = $this->seq[$i];
 629
 630                         $x1 = $xoff + (int)(($numer + ($xlim-$xoff)*$chunk) / $nchunks);
 631                         for ( ; $x < $x1; $x++) {
 632                                 $line = $flip ? $this->yv[$x] : $this->xv[$x];
 633                                         if (empty($ymatches[$line]))
 634                                                 continue;
 635                                 $matches = $ymatches[$line];
 636                                 reset($matches);
 637                                 while (list ($junk, $y) = each($matches))
 638                                         if (empty($this->in_seq[$y])) {
 639                                                 $k = $this->_lcs_pos($y);
 640                                                 USE_ASSERTS && assert($k > 0);
 641                                                 $ymids[$k] = $ymids[$k-1];
 642                                                 break;
 643                                         }
 644                                 while (list ($junk, $y) = each($matches)) {
 645                                         if ($y > $this->seq[$k-1]) {
 646                                                 USE_ASSERTS && assert($y < $this->seq[$k]);
 647                                                 // Optimization: this is a common case:
 648                                                 //      next match is just replacing previous match.
 649                                                 $this->in_seq[$this->seq[$k]] = false;
 650                                                 $this->seq[$k] = $y;
 651                                                 $this->in_seq[$y] = 1;
 652                                         } else if (empty($this->in_seq[$y])) {
 653                                                 $k = $this->_lcs_pos($y);
 654                                                 USE_ASSERTS && assert($k > 0);
 655                                                 $ymids[$k] = $ymids[$k-1];
 656                                         }
 657                                 }
 658                         }
 659                         wfProfileOut( "$fname-chunk" );
 660                 }
 661
 662                 $seps[] = $flip ? array($yoff, $xoff) : array($xoff, $yoff);
 663                 $ymid = $ymids[$this->lcs];
 664                 for ($n = 0; $n < $nchunks - 1; $n++) {
 665                         $x1 = $xoff + (int)(($numer + ($xlim - $xoff) * $n) / $nchunks);
 666                         $y1 = $ymid[$n] + 1;
 667                         $seps[] = $flip ? array($y1, $x1) : array($x1, $y1);
 668                 }
 669                 $seps[] = $flip ? array($ylim, $xlim) : array($xlim, $ylim);
 670
 671                 wfProfileOut( $fname );
 672                 return array($this->lcs, $seps);
 673         }
 674
 675         function _lcs_pos ($ypos) {
 676                 $fname = '_DiffEngine::_lcs_pos';
 677                 wfProfileIn( $fname );
 678
 679                 $end = $this->lcs;
 680                 if ($end == 0 || $ypos > $this->seq[$end]) {
 681                         $this->seq[++$this->lcs] = $ypos;
 682                         $this->in_seq[$ypos] = 1;
 683                         wfProfileOut( $fname );
 684                         return $this->lcs;
 685                 }
 686
 687                 $beg = 1;
 688                 while ($beg < $end) {
 689                         $mid = (int)(($beg + $end) / 2);
 690                         if ( $ypos > $this->seq[$mid] )
 691                                 $beg = $mid + 1;
 692                         else
 693                                 $end = $mid;
 694                 }
 695
 696                 USE_ASSERTS && assert($ypos != $this->seq[$end]);
 697
 698                 $this->in_seq[$this->seq[$end]] = false;
 699                 $this->seq[$end] = $ypos;
 700                 $this->in_seq[$ypos] = 1;
 701                 wfProfileOut( $fname );
 702                 return $end;
 703         }
 704
 705         /* Find LCS of two sequences.
 706          *
 707          * The results are recorded in the vectors $this->{x,y}changed[], by
 708          * storing a 1 in the element for each line that is an insertion
 709          * or deletion (ie. is not in the LCS).
 710          *
 711          * The subsequence of file 0 is [XOFF, XLIM) and likewise for file 1.
 712          *
 713          * Note that XLIM, YLIM are exclusive bounds.
 714          * All line numbers are origin-0 and discarded lines are not counted.
 715          */
 716         function _compareseq ($xoff, $xlim, $yoff, $ylim) {
 717                 $fname = '_DiffEngine::_compareseq';
 718                 wfProfileIn( $fname );
 719
 720                 // Slide down the bottom initial diagonal.
 721                 while ($xoff < $xlim && $yoff < $ylim
 722                            && $this->xv[$xoff] == $this->yv[$yoff]) {
 723                         ++$xoff;
 724                         ++$yoff;
 725                 }
 726
 727                 // Slide up the top initial diagonal.
 728                 while ($xlim > $xoff && $ylim > $yoff
 729                            && $this->xv[$xlim - 1] == $this->yv[$ylim - 1]) {
 730                         --$xlim;
 731                         --$ylim;
 732                 }
 733
 734                 if ($xoff == $xlim || $yoff == $ylim)
 735                         $lcs = 0;
 736                 else {
 737                         // This is ad hoc but seems to work well.
 738                         //$nchunks = sqrt(min($xlim - $xoff, $ylim - $yoff) / 2.5);
 739                         //$nchunks = max(2,min(8,(int)$nchunks));
 740                         $nchunks = min(7, $xlim - $xoff, $ylim - $yoff) + 1;
 741                         list ($lcs, $seps)
 742                         = $this->_diag($xoff,$xlim,$yoff, $ylim,$nchunks);
 743                 }
 744
 745                 if ($lcs == 0) {
 746                         // X and Y sequences have no common subsequence:
 747                         // mark all changed.
 748                         while ($yoff < $ylim)
 749                                 $this->ychanged[$this->yind[$yoff++]] = 1;
 750                         while ($xoff < $xlim)
 751                                 $this->xchanged[$this->xind[$xoff++]] = 1;
 752                 } else {
 753                         // Use the partitions to split this problem into subproblems.
 754                         reset($seps);
 755                         $pt1 = $seps[0];
 756                         while ($pt2 = next($seps)) {
 757                                 $this->_compareseq ($pt1[0], $pt2[0], $pt1[1], $pt2[1]);
 758                                 $pt1 = $pt2;
 759                         }
 760                 }
 761                 wfProfileOut( $fname );
 762         }
 763
 764         /* Adjust inserts/deletes of identical lines to join changes
 765          * as much as possible.
 766          *
 767          * We do something when a run of changed lines include a
 768          * line at one end and has an excluded, identical line at the other.
 769          * We are free to choose which identical line is included.
 770          * `compareseq' usually chooses the one at the beginning,
 771          * but usually it is cleaner to consider the following identical line
 772          * to be the "change".
 773          *
 774          * This is extracted verbatim from analyze.c (GNU diffutils-2.7).
 775          */
 776         function _shift_boundaries ($lines, &$changed, $other_changed) {
 777                 $fname = '_DiffEngine::_shift_boundaries';
 778                 wfProfileIn( $fname );
 779                 $i = 0;
 780                 $j = 0;
 781
 782                 USE_ASSERTS && assert('sizeof($lines) == sizeof($changed)');
 783                 $len = sizeof($lines);
 784                 $other_len = sizeof($other_changed);
 785
 786                 while (1) {
 787                         /*
 788                          * Scan forwards to find beginning of another run of changes.
 789                          * Also keep track of the corresponding point in the other file.
 790                          *
 791                          * Throughout this code, $i and $j are adjusted together so that
 792                          * the first $i elements of $changed and the first $j elements
 793                          * of $other_changed both contain the same number of zeros
 794                          * (unchanged lines).
 795                          * Furthermore, $j is always kept so that $j == $other_len or
 796                          * $other_changed[$j] == false.
 797                          */
 798                         while ($j < $other_len && $other_changed[$j])
 799                                 $j++;
 800
 801                         while ($i < $len && ! $changed[$i]) {
 802                                 USE_ASSERTS && assert('$j < $other_len && ! $other_changed[$j]');
 803                                 $i++; $j++;
 804                                 while ($j < $other_len && $other_changed[$j])
 805                                         $j++;
 806                         }
 807
 808                         if ($i == $len)
 809                                 break;
 810
 811                         $start = $i;
 812
 813                         // Find the end of this run of changes.
 814                         while (++$i < $len && $changed[$i])
 815                                 continue;
 816
 817                         do {
 818                                 /*
 819                                  * Record the length of this run of changes, so that
 820                                  * we can later determine whether the run has grown.
 821                                  */
 822                                 $runlength = $i - $start;
 823
 824                                 /*
 825                                  * Move the changed region back, so long as the
 826                                  * previous unchanged line matches the last changed one.
 827                                  * This merges with previous changed regions.
 828                                  */
 829                                 while ($start > 0 && $lines[$start - 1] == $lines[$i - 1]) {
 830                                         $changed[--$start] = 1;
 831                                         $changed[--$i] = false;
 832                                         while ($start > 0 && $changed[$start - 1])
 833                                                 $start--;
 834                                         USE_ASSERTS && assert('$j > 0');
 835                                         while ($other_changed[--$j])
 836                                                 continue;
 837                                         USE_ASSERTS && assert('$j >= 0 && !$other_changed[$j]');
 838                                 }
 839
 840                                 /*
 841                                  * Set CORRESPONDING to the end of the changed run, at the last
 842                                  * point where it corresponds to a changed run in the other file.
 843                                  * CORRESPONDING == LEN means no such point has been found.
 844                                  */
 845                                 $corresponding = $j < $other_len ? $i : $len;
 846
 847                                 /*
 848                                  * Move the changed region forward, so long as the
 849                                  * first changed line matches the following unchanged one.
 850                                  * This merges with following changed regions.
 851                                  * Do this second, so that if there are no merges,
 852                                  * the changed region is moved forward as far as possible.
 853                                  */
 854                                 while ($i < $len && $lines[$start] == $lines[$i]) {
 855                                         $changed[$start++] = false;
 856                                         $changed[$i++] = 1;
 857                                         while ($i < $len && $changed[$i])
 858                                                 $i++;
 859
 860                                         USE_ASSERTS && assert('$j < $other_len && ! $other_changed[$j]');
 861                                         $j++;
 862                                         if ($j < $other_len && $other_changed[$j]) {
 863                                                 $corresponding = $i;
 864                                                 while ($j < $other_len && $other_changed[$j])
 865                                                         $j++;
 866                                         }
 867                                 }
 868                         } while ($runlength != $i - $start);
 869
 870                         /*
 871                          * If possible, move the fully-merged run of changes
 872                          * back to a corresponding run in the other file.
 873                          */
 874                         while ($corresponding < $i) {
 875                                 $changed[--$start] = 1;
 876                                 $changed[--$i] = 0;
 877                                 USE_ASSERTS && assert('$j > 0');
 878                                 while ($other_changed[--$j])
 879                                         continue;
 880                                 USE_ASSERTS && assert('$j >= 0 && !$other_changed[$j]');
 881                         }
 882                 }
 883                 wfProfileOut( $fname );
 884         }
 885 }
 886
 887 /**
 888  * Class representing a 'diff' between two sequences of strings.
 889  * @todo document
 890  * @access private
 891  * @package MediaWiki
 892  * @subpackage DifferenceEngine
 893  */
 894 class Diff
 895 {
 896         var $edits;
 897
 898         /**
 899          * Constructor.
 900          * Computes diff between sequences of strings.
 901          *
 902          * @param $from_lines array An array of strings.
 903          *                (Typically these are lines from a file.)
 904          * @param $to_lines array An array of strings.
 905          */
 906         function Diff($from_lines, $to_lines) {
 907                 $eng = new _DiffEngine;
 908                 $this->edits = $eng->diff($from_lines, $to_lines);
 909                 //$this->_check($from_lines, $to_lines);
 910         }
 911
 912         /**
 913          * Compute reversed Diff.
 914          *
 915          * SYNOPSIS:
 916          *
 917          *      $diff = new Diff($lines1, $lines2);
 918          *      $rev = $diff->reverse();
 919          * @return object A Diff object representing the inverse of the
 920          *                                original diff.
 921          */
 922         function reverse () {
 923                 $rev = $this;
 924                 $rev->edits = array();
 925                 foreach ($this->edits as $edit) {
 926                         $rev->edits[] = $edit->reverse();
 927                 }
 928                 return $rev;
 929         }
 930
 931         /**
 932          * Check for empty diff.
 933          *
 934          * @return bool True iff two sequences were identical.
 935          */
 936         function isEmpty () {
 937                 foreach ($this->edits as $edit) {
 938                         if ($edit->type != 'copy')
 939                                 return false;
 940                 }
 941                 return true;
 942         }
 943
 944         /**
 945          * Compute the length of the Longest Common Subsequence (LCS).
 946          *
 947          * This is mostly for diagnostic purposed.
 948          *
 949          * @return int The length of the LCS.
 950          */
 951         function lcs () {
 952                 $lcs = 0;
 953                 foreach ($this->edits as $edit) {
 954                         if ($edit->type == 'copy')
 955                                 $lcs += sizeof($edit->orig);
 956                 }
 957                 return $lcs;
 958         }
 959
 960         /**
 961          * Get the original set of lines.
 962          *
 963          * This reconstructs the $from_lines parameter passed to the
 964          * constructor.
 965          *
 966          * @return array The original sequence of strings.
 967          */
 968         function orig() {
 969                 $lines = array();
 970
 971                 foreach ($this->edits as $edit) {
 972                         if ($edit->orig)
 973                                 array_splice($lines, sizeof($lines), 0, $edit->orig);
 974                 }
 975                 return $lines;
 976         }
 977
 978         /**
 979          * Get the closing set of lines.
 980          *
 981          * This reconstructs the $to_lines parameter passed to the
 982          * constructor.
 983          *
 984          * @return array The sequence of strings.
 985          */
 986         function closing() {
 987                 $lines = array();
 988
 989                 foreach ($this->edits as $edit) {
 990                         if ($edit->closing)
 991                                 array_splice($lines, sizeof($lines), 0, $edit->closing);
 992                 }
 993                 return $lines;
 994         }
 995
 996         /**
 997          * Check a Diff for validity.
 998          *
 999          * This is here only for debugging purposes.
1000          */
1001         function _check ($from_lines, $to_lines) {
1002                 $fname = 'Diff::_check';
1003                 wfProfileIn( $fname );
1004                 if (serialize($from_lines) != serialize($this->orig()))
1005                         trigger_error("Reconstructed original doesn't match", E_USER_ERROR);
1006                 if (serialize($to_lines) != serialize($this->closing()))
1007                         trigger_error("Reconstructed closing doesn't match", E_USER_ERROR);
1008
1009                 $rev = $this->reverse();
1010                 if (serialize($to_lines) != serialize($rev->orig()))
1011                         trigger_error("Reversed original doesn't match", E_USER_ERROR);
1012                 if (serialize($from_lines) != serialize($rev->closing()))
1013                         trigger_error("Reversed closing doesn't match", E_USER_ERROR);
1014
1015
1016                 $prevtype = 'none';
1017                 foreach ($this->edits as $edit) {
1018                         if ( $prevtype == $edit->type )
1019                                 trigger_error("Edit sequence is non-optimal", E_USER_ERROR);
1020                         $prevtype = $edit->type;
1021                 }
1022
1023                 $lcs = $this->lcs();
1024                 trigger_error('Diff okay: LCS = '.$lcs, E_USER_NOTICE);
1025                 wfProfileOut( $fname );
1026         }
1027 }
1028
1029 /**
1030  * FIXME: bad name.
1031  * @todo document
1032  * @access private
1033  * @package MediaWiki
1034  * @subpackage DifferenceEngine
1035  */
1036 class MappedDiff extends Diff
1037 {
1038         /**
1039          * Constructor.
1040          *
1041          * Computes diff between sequences of strings.
1042          *
1043          * This can be used to compute things like
1044          * case-insensitve diffs, or diffs which ignore
1045          * changes in white-space.
1046          *
1047          * @param $from_lines array An array of strings.
1048          *      (Typically these are lines from a file.)
1049          *
1050          * @param $to_lines array An array of strings.
1051          *
1052          * @param $mapped_from_lines array This array should
1053          *      have the same size number of elements as $from_lines.
1054          *      The elements in $mapped_from_lines and
1055          *      $mapped_to_lines are what is actually compared
1056          *      when computing the diff.
1057          *
1058          * @param $mapped_to_lines array This array should
1059          *      have the same number of elements as $to_lines.
1060          */
1061         function MappedDiff($from_lines, $to_lines,
1062                                                 $mapped_from_lines, $mapped_to_lines) {
1063                 $fname = 'MappedDiff::MappedDiff';
1064                 wfProfileIn( $fname );
1065
1066                 assert(sizeof($from_lines) == sizeof($mapped_from_lines));
1067                 assert(sizeof($to_lines) == sizeof($mapped_to_lines));
1068
1069                 $this->Diff($mapped_from_lines, $mapped_to_lines);
1070
1071                 $xi = $yi = 0;
1072                 for ($i = 0; $i < sizeof($this->edits); $i++) {
1073                         $orig = &$this->edits[$i]->orig;
1074                         if (is_array($orig)) {
1075                                 $orig = array_slice($from_lines, $xi, sizeof($orig));
1076                                 $xi += sizeof($orig);
1077                         }
1078
1079                         $closing = &$this->edits[$i]->closing;
1080                         if (is_array($closing)) {
1081                                 $closing = array_slice($to_lines, $yi, sizeof($closing));
1082                                 $yi += sizeof($closing);
1083                         }
1084                 }
1085                 wfProfileOut( $fname );
1086         }
1087 }
1088
1089 /**
1090  * A class to format Diffs
1091  *
1092  * This class formats the diff in classic diff format.
1093  * It is intended that this class be customized via inheritance,
1094  * to obtain fancier outputs.
1095  * @todo document
1096  * @access private
1097  * @package MediaWiki
1098  * @subpackage DifferenceEngine
1099  */
1100 class DiffFormatter
1101 {
1102         /**
1103          * Number of leading context "lines" to preserve.
1104          *
1105          * This should be left at zero for this class, but subclasses
1106          * may want to set this to other values.
1107          */
1108         var $leading_context_lines = 0;
1109
1110         /**
1111          * Number of trailing context "lines" to preserve.
1112          *
1113          * This should be left at zero for this class, but subclasses
1114          * may want to set this to other values.
1115          */
1116         var $trailing_context_lines = 0;
1117
1118         /**
1119          * Format a diff.
1120          *
1121          * @param $diff object A Diff object.
1122          * @return string The formatted output.
1123          */
1124         function format($diff) {
1125                 $fname = 'DiffFormatter::format';
1126                 wfProfileIn( $fname );
1127
1128                 $xi = $yi = 1;
1129                 $block = false;
1130                 $context = array();
1131
1132                 $nlead = $this->leading_context_lines;
1133                 $ntrail = $this->trailing_context_lines;
1134
1135                 $this->_start_diff();
1136
1137                 foreach ($diff->edits as $edit) {
1138                         if ($edit->type == 'copy') {
1139                                 if (is_array($block)) {
1140                                         if (sizeof($edit->orig) <= $nlead + $ntrail) {
1141                                                 $block[] = $edit;
1142                                         }
1143                                         else{
1144                                                 if ($ntrail) {
1145                                                         $context = array_slice($edit->orig, 0, $ntrail);
1146                                                         $block[] = new _DiffOp_Copy($context);
1147                                                 }
1148                                                 $this->_block($x0, $ntrail + $xi - $x0,
1149                                                                           $y0, $ntrail + $yi - $y0,
1150                                                                           $block);
1151                                                 $block = false;
1152                                         }
1153                                 }
1154                                 $context = $edit->orig;
1155                         }
1156                         else {
1157                                 if (! is_array($block)) {
1158                                         $context = array_slice($context, sizeof($context) - $nlead);
1159                                         $x0 = $xi - sizeof($context);
1160                                         $y0 = $yi - sizeof($context);
1161                                         $block = array();
1162                                         if ($context)
1163                                                 $block[] = new _DiffOp_Copy($context);
1164                                 }
1165                                 $block[] = $edit;
1166                         }
1167
1168                         if ($edit->orig)
1169                                 $xi += sizeof($edit->orig);
1170                         if ($edit->closing)
1171                                 $yi += sizeof($edit->closing);
1172                 }
1173
1174                 if (is_array($block))
1175                         $this->_block($x0, $xi - $x0,
1176                                                   $y0, $yi - $y0,
1177                                                   $block);
1178
1179                 $end = $this->_end_diff();
1180                 wfProfileOut( $fname );
1181                 return $end;
1182         }
1183
1184         function _block($xbeg, $xlen, $ybeg, $ylen, &$edits) {
1185                 $fname = 'DiffFormatter::_block';
1186                 wfProfileIn( $fname );
1187                 $this->_start_block($this->_block_header($xbeg, $xlen, $ybeg, $ylen));
1188                 foreach ($edits as $edit) {
1189                         if ($edit->type == 'copy')
1190                                 $this->_context($edit->orig);
1191                         elseif ($edit->type == 'add')
1192                                 $this->_added($edit->closing);
1193                         elseif ($edit->type == 'delete')
1194                                 $this->_deleted($edit->orig);
1195                         elseif ($edit->type == 'change')
1196                                 $this->_changed($edit->orig, $edit->closing);
1197                         else
1198                                 trigger_error('Unknown edit type', E_USER_ERROR);
1199                 }
1200                 $this->_end_block();
1201                 wfProfileOut( $fname );
1202         }
1203
1204         function _start_diff() {
1205                 ob_start();
1206         }
1207
1208         function _end_diff() {
1209                 $val = ob_get_contents();
1210                 ob_end_clean();
1211                 return $val;
1212         }
1213
1214         function _block_header($xbeg, $xlen, $ybeg, $ylen) {
1215                 if ($xlen > 1)
1216                         $xbeg .= "," . ($xbeg + $xlen - 1);
1217                 if ($ylen > 1)
1218                         $ybeg .= "," . ($ybeg + $ylen - 1);
1219
1220                 return $xbeg . ($xlen ? ($ylen ? 'c' : 'd') : 'a') . $ybeg;
1221         }
1222
1223         function _start_block($header) {
1224                 echo $header;
1225         }
1226
1227         function _end_block() {
1228         }
1229
1230         function _lines($lines, $prefix = ' ') {
1231                 foreach ($lines as $line)
1232                         echo "$prefix $line\n";
1233         }
1234
1235         function _context($lines) {
1236                 $this->_lines($lines);
1237         }
1238
1239         function _added($lines) {
1240                 $this->_lines($lines, '>');
1241         }
1242         function _deleted($lines) {
1243                 $this->_lines($lines, '<');
1244         }
1245
1246         function _changed($orig, $closing) {
1247                 $this->_deleted($orig);
1248                 echo "---\n";
1249                 $this->_added($closing);
1250         }
1251 }
1252
1253
1254 /**
1255  *      Additions by Axel Boldt follow, partly taken from diff.php, phpwiki-1.3.3
1256  *
1257  */
1258
1259 define('NBSP', '&#160;');                       // iso-8859-x non-breaking space.
1260
1261 /**
1262  * @todo document
1263  * @access private
1264  * @package MediaWiki
1265  * @subpackage DifferenceEngine
1266  */
1267 class _HWLDF_WordAccumulator {
1268         function _HWLDF_WordAccumulator () {
1269                 $this->_lines = array();
1270                 $this->_line = '';
1271                 $this->_group = '';
1272                 $this->_tag = '';
1273         }
1274
1275         function _flushGroup ($new_tag) {
1276                 if ($this->_group !== '') {
1277                         if ($this->_tag == 'mark')
1278                                 $this->_line .= '<span class="diffchange">' .
1279                                         htmlspecialchars ( $this->_group ) . '</span>';
1280                         else
1281                                 $this->_line .= htmlspecialchars ( $this->_group );
1282                 }
1283                 $this->_group = '';
1284                 $this->_tag = $new_tag;
1285         }
1286
1287         function _flushLine ($new_tag) {
1288                 $this->_flushGroup($new_tag);
1289                 if ($this->_line != '')
1290                         array_push ( $this->_lines, $this->_line );
1291                 else
1292                         # make empty lines visible by inserting an NBSP
1293                         array_push ( $this->_lines, NBSP );
1294                 $this->_line = '';
1295         }
1296
1297         function addWords ($words, $tag = '') {
1298                 if ($tag != $this->_tag)
1299                         $this->_flushGroup($tag);
1300
1301                 foreach ($words as $word) {
1302                         // new-line should only come as first char of word.
1303                         if ($word == '')
1304                                 continue;
1305                         if ($word[0] == "\n") {
1306                                 $this->_flushLine($tag);
1307                                 $word = substr($word, 1);
1308                         }
1309                         assert(!strstr($word, "\n"));
1310                         $this->_group .= $word;
1311                 }
1312         }
1313
1314         function getLines() {
1315                 $this->_flushLine('~done');
1316                 return $this->_lines;
1317         }
1318 }
1319
1320 /**
1321  * @todo document
1322  * @access private
1323  * @package MediaWiki
1324  * @subpackage DifferenceEngine
1325  */
1326 class WordLevelDiff extends MappedDiff
1327 {
1328         function WordLevelDiff ($orig_lines, $closing_lines) {
1329                 $fname = 'WordLevelDiff::WordLevelDiff';
1330                 wfProfileIn( $fname );
1331
1332                 list ($orig_words, $orig_stripped) = $this->_split($orig_lines);
1333                 list ($closing_words, $closing_stripped) = $this->_split($closing_lines);
1334
1335
1336                 $this->MappedDiff($orig_words, $closing_words,
1337                                                   $orig_stripped, $closing_stripped);
1338                 wfProfileOut( $fname );
1339         }
1340
1341         function _split($lines) {
1342                 $fname = 'WordLevelDiff::_split';
1343                 wfProfileIn( $fname );
1344                 if (!preg_match_all('/ ( [^\S\n]+ | [0-9_A-Za-z\x80-\xff]+ | . ) (?: (?!< \n) [^\S\n])? /xs',
1345                                                         implode("\n", $lines),
1346                                                         $m)) {
1347                         wfProfileOut( $fname );
1348                         return array(array(''), array(''));
1349                 }
1350                 wfProfileOut( $fname );
1351                 return array($m[0], $m[1]);
1352         }
1353
1354         function orig () {
1355                 $fname = 'WordLevelDiff::orig';
1356                 wfProfileIn( $fname );
1357                 $orig = new _HWLDF_WordAccumulator;
1358
1359                 foreach ($this->edits as $edit) {
1360                         if ($edit->type == 'copy')
1361                                 $orig->addWords($edit->orig);
1362                         elseif ($edit->orig)
1363                                 $orig->addWords($edit->orig, 'mark');
1364                 }
1365                 $lines = $orig->getLines();
1366                 wfProfileOut( $fname );
1367                 return $lines;
1368         }
1369
1370         function closing () {
1371                 $fname = 'WordLevelDiff::closing';
1372                 wfProfileIn( $fname );
1373                 $closing = new _HWLDF_WordAccumulator;
1374
1375                 foreach ($this->edits as $edit) {
1376                         if ($edit->type == 'copy')
1377                                 $closing->addWords($edit->closing);
1378                         elseif ($edit->closing)
1379                                 $closing->addWords($edit->closing, 'mark');
1380                 }
1381                 $lines = $closing->getLines();
1382                 wfProfileOut( $fname );
1383                 return $lines;
1384         }
1385 }
1386
1387 /**
1388  *      Wikipedia Table style diff formatter.
1389  * @todo document
1390  * @access private
1391  * @package MediaWiki
1392  * @subpackage DifferenceEngine
1393  */
1394 class TableDiffFormatter extends DiffFormatter
1395 {
1396         function TableDiffFormatter() {
1397                 $this->leading_context_lines = 2;
1398                 $this->trailing_context_lines = 2;
1399         }
1400
1401         function _block_header( $xbeg, $xlen, $ybeg, $ylen ) {
1402                 $l1 = wfMsg( 'lineno', $xbeg );
1403                 $l2 = wfMsg( 'lineno', $ybeg );
1404
1405                 $r = '<tr><td colspan="2" align="left"><strong>'.$l1."</strong></td>\n" .
1406                   '<td colspan="2" align="left"><strong>'.$l2."</strong></td></tr>\n";
1407                 return $r;
1408         }
1409
1410         function _start_block( $header ) {
1411                 global $wgOut;
1412                 echo $header;
1413         }
1414
1415         function _end_block() {
1416         }
1417
1418         function _lines( $lines, $prefix=' ', $color='white' ) {
1419         }
1420
1421         # HTML-escape parameter before calling this
1422         function addedLine( $line ) {
1423                 return "<td>+</td><td class='diff-addedline'>{$line}</td>";
1424         }
1425
1426         # HTML-escape parameter before calling this
1427         function deletedLine( $line ) {
1428                 return "<td>-</td><td class='diff-deletedline'>{$line}</td>";
1429         }
1430
1431         # HTML-escape parameter before calling this
1432         function contextLine( $line ) {
1433                 return "<td> </td><td class='diff-context'>{$line}</td>";
1434         }
1435
1436         function emptyLine() {
1437                 return '<td colspan="2">&nbsp;</td>';
1438         }
1439
1440         function _added( $lines ) {
1441                 foreach ($lines as $line) {
1442                         echo '<tr>' . $this->emptyLine() .
1443                                 $this->addedLine( htmlspecialchars ( $line ) ) . "</tr>\n";
1444                 }
1445         }
1446
1447         function _deleted($lines) {
1448                 foreach ($lines as $line) {
1449                         echo '<tr>' . $this->deletedLine( htmlspecialchars ( $line ) ) .
1450                           $this->emptyLine() . "</tr>\n";
1451                 }
1452         }
1453
1454         function _context( $lines ) {
1455                 foreach ($lines as $line) {
1456                         echo '<tr>' .
1457                                 $this->contextLine( htmlspecialchars ( $line ) ) .
1458                                 $this->contextLine( htmlspecialchars ( $line ) ) . "</tr>\n";
1459                 }
1460         }
1461
1462         function _changed( $orig, $closing ) {
1463                 $fname = 'TableDiffFormatter::_changed';
1464                 wfProfileIn( $fname );
1465
1466                 $diff = new WordLevelDiff( $orig, $closing );
1467                 $del = $diff->orig();
1468                 $add = $diff->closing();
1469
1470                 # Notice that WordLevelDiff returns HTML-escaped output.
1471                 # Hence, we will be calling addedLine/deletedLine without HTML-escaping.
1472
1473                 while ( $line = array_shift( $del ) ) {
1474                         $aline = array_shift( $add );
1475                         echo '<tr>' . $this->deletedLine( $line ) .
1476                                 $this->addedLine( $aline ) . "</tr>\n";
1477                 }
1478                 foreach ($add as $line) {       # If any leftovers
1479                         echo '<tr>' . $this->emptyLine() .
1480                                 $this->addedLine( $line ) . "</tr>\n";
1481                 }
1482                 wfProfileOut( $fname );
1483         }
1484 }
1485
1486 ?>