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