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->newRev->isCurrent() ) {
 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
 190                 if( !$this->newRev->isCurrent() ) {
 191                         $oldEditSectionSetting = $wgOut->mParserOptions->setEditSection( false );
 192                 }
 193                 $wgOut->addWikiText( $this->mNewtext );
 194                 if( !$this->newRev->isCurrent() ) {
 195                         $wgOut->mParserOptions->setEditSection( $oldEditSectionSetting );
 196                 }
 197
 198                 wfProfileOut( $fname );
 199         }
 200
 201         /**
 202          * Show the first revision of an article. Uses normal diff headers in
 203          * contrast to normal "old revision" display style.
 204          */
 205         function showFirstRevision() {
 206                 global $wgOut, $wgTitle, $wgUser, $wgLang;
 207
 208                 $fname = 'DifferenceEngine::showFirstRevision';
 209                 wfProfileIn( $fname );
 210
 211
 212                 $this->mOldid = $this->mNewid; # hack to make loadText() work.
 213
 214                 # Get article text from the DB
 215                 #
 216                 if ( ! $this->loadText() ) {
 217                         $t = $wgTitle->getPrefixedText() . " (Diff: {$this->mOldid}, " .
 218                           "{$this->mNewid})";
 219                         $mtext = wfMsg( 'missingarticle', $t );
 220                         $wgOut->setPagetitle( wfMsg( 'errorpagetitle' ) );
 221                         $wgOut->addHTML( $mtext );
 222                         wfProfileOut( $fname );
 223                         return;
 224                 }
 225
 226                 # Check if user is allowed to look at this page. If not, bail out.
 227                 #
 228                 if ( !( $this->mOldPage->userCanRead() ) ) {
 229                         $wgOut->loginToUse();
 230                         $wgOut->output();
 231                         wfProfileOut( $fname );
 232                         exit;
 233                 }
 234
 235                 # Prepare the header box
 236                 #
 237                 $sk = $wgUser->getSkin();
 238
 239                 $uTLink = $sk->makeLinkObj( Title::makeTitleSafe( NS_USER_TALK, $this->mOldUser ),  $wgLang->getNsText( NS_TALK ) );
 240                 $userLink = $sk->makeLinkObj( Title::makeTitleSafe( NS_USER, $this->mOldUser ), $this->mOldUser );
 241                 $contribs = $sk->makeKnownLinkObj( Title::makeTitle( NS_SPECIAL, 'Contributions' ), wfMsg( 'contribslink' ),
 242                         'target=' . urlencode($this->mOldUser) );
 243                 $nextlink = $sk->makeKnownLinkObj( $wgTitle, wfMsg( 'nextdiff' ), 'diff=next&oldid='.$this->mNewid );
 244                 $header = "<div class=\"firstrevisionheader\" style=\"text-align: center\"><strong>{$this->mOldtitle}</strong><br />$userLink " .
 245                         "($uTLink | $contribs)<br />" . $this->mOldComment .
 246                         '<br />' . $nextlink. "</div>\n";
 247
 248                 $wgOut->addHTML( $header );
 249
 250                 $wgOut->setSubtitle( wfMsg( 'difference' ) );
 251                 $wgOut->setRobotpolicy( 'noindex,follow' );
 252
 253
 254                 # Show current revision
 255                 #
 256                 $wgOut->addHTML( "<hr /><h2>{$this->mPagetitle}</h2>\n" );
 257                 $wgOut->addWikiText( $this->mNewtext );
 258
 259                 wfProfileOut( $fname );
 260         }
 261
 262         function showDiff( $otext, $ntext, $otitle, $ntitle ) {
 263                 global $wgOut;
 264                 $wgOut->addHTML( DifferenceEngine::getDiff( $otext, $ntext, $otitle, $ntitle ) );
 265         }
 266
 267         function getDiff( $otext, $ntext, $otitle, $ntitle ) {
 268                 global $wgUseExternalDiffEngine, $wgContLang;
 269                 $out = "
 270                         <table border='0' width='98%' cellpadding='0' cellspacing='4' class='diff'>
 271                         <tr>
 272                                 <td colspan='2' width='50%' align='center' class='diff-otitle'>{$otitle}</td>
 273                                 <td colspan='2' width='50%' align='center' class='diff-ntitle'>{$ntitle}</td>
 274                         </tr>
 275                 ";
 276                 $otext = $wgContLang->segmentForDiff($otext);
 277                 $ntext = $wgContLang->segmentForDiff($ntext);
 278                 $difftext='';
 279                 if ( $wgUseExternalDiffEngine ) {
 280                         # For historical reasons, external diff engine expects
 281                         # input text to be HTML-escaped already
 282                         $otext = str_replace( "\r\n", "\n", htmlspecialchars ( $otext ) );
 283                         $ntext = str_replace( "\r\n", "\n", htmlspecialchars ( $ntext ) );
 284                         if( !function_exists( 'wikidiff_do_diff' ) ) {
 285                                 dl('php_wikidiff.so');
 286                         }
 287                         $difftext = wikidiff_do_diff( $otext, $ntext, 2 );
 288                 } else {
 289                         $ota = explode( "\n", str_replace( "\r\n", "\n", $otext ) );
 290                         $nta = explode( "\n", str_replace( "\r\n", "\n", $ntext ) );
 291                         $diffs =& new Diff( $ota, $nta );
 292                         $formatter =& new TableDiffFormatter();
 293                         $difftext = $formatter->format( $diffs );
 294                 }
 295                 $difftext = $wgContLang->unsegmentForDiff($difftext);
 296                 $out .= $difftext."</table>\n";
 297                 return $out;
 298         }
 299
 300         /**
 301          * Load the text of the articles to compare.  If newid is 0, then compare
 302          * the old article in oldid to the current article; if oldid is 0, then
 303          * compare the current article to the immediately previous one (ignoring the
 304          * value of newid).
 305          */
 306         function loadText() {
 307                 global $wgTitle, $wgOut, $wgLang;
 308                 $fname = 'DifferenceEngine::loadText';
 309
 310                 $dbr =& wfGetDB( DB_SLAVE );
 311                 if( $this->mNewid ) {
 312                         $this->newRev = Revision::newFromId( $this->mNewid );
 313                 } else {
 314                         $this->newRev = Revision::newFromTitle( $wgTitle );
 315                 }
 316                 if( is_null( $this->newRev ) ) {
 317                         return false;
 318                 }
 319
 320                 if( $this->newRev->isCurrent() ) {
 321                         $wgOut->setArticleFlag( true );
 322                         $this->mPagetitle = htmlspecialchars( wfMsg( 'currentrev' ) );
 323                         $this->mNewPage = $wgTitle;
 324                         $newLink = $this->mNewPage->escapeLocalUrl();
 325                         $this->mNewtitle = "<a href='$newLink'>{$this->mPagetitle}</a>";
 326                 } else {
 327                         $this->mNewPage = $this->newRev->getTitle();
 328                         $newLink = $this->mNewPage->escapeLocalUrl ('oldid=' . $this->mNewid );
 329                         $t = $wgLang->timeanddate( $this->newRev->getTimestamp(), true );
 330                         $this->mPagetitle = htmlspecialchars( wfMsg( 'revisionasof', $t ) );
 331                         $this->mNewtitle = "<a href='$newLink'>{$this->mPagetitle}</a>";
 332                 }
 333
 334                 if( $this->mOldid ) {
 335                         $this->oldRev = Revision::newFromId( $this->mOldid );
 336                 } else {
 337                         $this->oldRev = $this->newRev->getPrevious();
 338                         $this->mOldid = $this->oldRev->getId();
 339                 }
 340                 if( is_null( $this->oldRev ) ) {
 341                         return false;
 342                 }
 343
 344                 $this->mOldPage = $this->oldRev->getTitle();
 345
 346                 $t = $wgLang->timeanddate( $this->oldRev->getTimestamp(), true );
 347                 $oldLink = $this->mOldPage->escapeLocalUrl( 'oldid=' . $this->mOldid );
 348                 $this->mOldtitle = "<a href='$oldLink'>" . htmlspecialchars( wfMsg( 'revisionasof', $t ) ) . '</a>';
 349
 350                 $this->mNewUser = $this->newRev->getUserText();
 351                 $this->mNewComment = $this->newRev->getComment();
 352                 $this->mNewtext = $this->newRev->getText();
 353
 354                 $this->mOldUser = $this->oldRev->getUserText();
 355                 $this->mOldComment = $this->oldRev->getComment();
 356                 $this->mOldtext = $this->oldRev->getText();
 357
 358                 return true;
 359         }
 360 }
 361
 362 // A PHP diff engine for phpwiki. (Taken from phpwiki-1.3.3)
 363 //
 364 // Copyright (C) 2000, 2001 Geoffrey T. Dairiki <dairiki@dairiki.org>
 365 // You may copy this code freely under the conditions of the GPL.
 366 //
 367
 368 define('USE_ASSERTS', function_exists('assert'));
 369
 370 /**
 371  * @todo document
 372  * @access private
 373  * @package MediaWiki
 374  * @subpackage DifferenceEngine
 375  */
 376 class _DiffOp {
 377         var $type;
 378         var $orig;
 379         var $closing;
 380
 381         function reverse() {
 382                 trigger_error('pure virtual', E_USER_ERROR);
 383         }
 384
 385         function norig() {
 386                 return $this->orig ? sizeof($this->orig) : 0;
 387         }
 388
 389         function nclosing() {
 390                 return $this->closing ? sizeof($this->closing) : 0;
 391         }
 392 }
 393
 394 /**
 395  * @todo document
 396  * @access private
 397  * @package MediaWiki
 398  * @subpackage DifferenceEngine
 399  */
 400 class _DiffOp_Copy extends _DiffOp {
 401         var $type = 'copy';
 402
 403         function _DiffOp_Copy ($orig, $closing = false) {
 404                 if (!is_array($closing))
 405                         $closing = $orig;
 406                 $this->orig = $orig;
 407                 $this->closing = $closing;
 408         }
 409
 410         function reverse() {
 411                 return new _DiffOp_Copy($this->closing, $this->orig);
 412         }
 413 }
 414
 415 /**
 416  * @todo document
 417  * @access private
 418  * @package MediaWiki
 419  * @subpackage DifferenceEngine
 420  */
 421 class _DiffOp_Delete extends _DiffOp {
 422         var $type = 'delete';
 423
 424         function _DiffOp_Delete ($lines) {
 425                 $this->orig = $lines;
 426                 $this->closing = false;
 427         }
 428
 429         function reverse() {
 430                 return new _DiffOp_Add($this->orig);
 431         }
 432 }
 433
 434 /**
 435  * @todo document
 436  * @access private
 437  * @package MediaWiki
 438  * @subpackage DifferenceEngine
 439  */
 440 class _DiffOp_Add extends _DiffOp {
 441         var $type = 'add';
 442
 443         function _DiffOp_Add ($lines) {
 444                 $this->closing = $lines;
 445                 $this->orig = false;
 446         }
 447
 448         function reverse() {
 449                 return new _DiffOp_Delete($this->closing);
 450         }
 451 }
 452
 453 /**
 454  * @todo document
 455  * @access private
 456  * @package MediaWiki
 457  * @subpackage DifferenceEngine
 458  */
 459 class _DiffOp_Change extends _DiffOp {
 460         var $type = 'change';
 461
 462         function _DiffOp_Change ($orig, $closing) {
 463                 $this->orig = $orig;
 464                 $this->closing = $closing;
 465         }
 466
 467         function reverse() {
 468                 return new _DiffOp_Change($this->closing, $this->orig);
 469         }
 470 }
 471
 472
 473 /**
 474  * Class used internally by Diff to actually compute the diffs.
 475  *
 476  * The algorithm used here is mostly lifted from the perl module
 477  * Algorithm::Diff (version 1.06) by Ned Konz, which is available at:
 478  *       http://www.perl.com/CPAN/authors/id/N/NE/NEDKONZ/Algorithm-Diff-1.06.zip
 479  *
 480  * More ideas are taken from:
 481  *       http://www.ics.uci.edu/~eppstein/161/960229.html
 482  *
 483  * Some ideas are (and a bit of code) are from from analyze.c, from GNU
 484  * diffutils-2.7, which can be found at:
 485  *       ftp://gnudist.gnu.org/pub/gnu/diffutils/diffutils-2.7.tar.gz
 486  *
 487  * closingly, some ideas (subdivision by NCHUNKS > 2, and some optimizations)
 488  * are my own.
 489  *
 490  * @author Geoffrey T. Dairiki
 491  * @access private
 492  * @package MediaWiki
 493  * @subpackage DifferenceEngine
 494  */
 495 class _DiffEngine
 496 {
 497         function diff ($from_lines, $to_lines) {
 498                 $fname = '_DiffEngine::diff';
 499                 wfProfileIn( $fname );
 500
 501                 $n_from = sizeof($from_lines);
 502                 $n_to = sizeof($to_lines);
 503
 504                 $this->xchanged = $this->ychanged = array();
 505                 $this->xv = $this->yv = array();
 506                 $this->xind = $this->yind = array();
 507                 unset($this->seq);
 508                 unset($this->in_seq);
 509                 unset($this->lcs);
 510
 511                 // Skip leading common lines.
 512                 for ($skip = 0; $skip < $n_from && $skip < $n_to; $skip++) {
 513                         if ($from_lines[$skip] != $to_lines[$skip])
 514                                 break;
 515                         $this->xchanged[$skip] = $this->ychanged[$skip] = false;
 516                 }
 517                 // Skip trailing common lines.
 518                 $xi = $n_from; $yi = $n_to;
 519                 for ($endskip = 0; --$xi > $skip && --$yi > $skip; $endskip++) {
 520                         if ($from_lines[$xi] != $to_lines[$yi])
 521                                 break;
 522                         $this->xchanged[$xi] = $this->ychanged[$yi] = false;
 523                 }
 524
 525                 // Ignore lines which do not exist in both files.
 526                 for ($xi = $skip; $xi < $n_from - $endskip; $xi++)
 527                         $xhash[$from_lines[$xi]] = 1;
 528                 for ($yi = $skip; $yi < $n_to - $endskip; $yi++) {
 529                         $line = $to_lines[$yi];
 530                         if ( ($this->ychanged[$yi] = empty($xhash[$line])) )
 531                                 continue;
 532                         $yhash[$line] = 1;
 533                         $this->yv[] = $line;
 534                         $this->yind[] = $yi;
 535                 }
 536                 for ($xi = $skip; $xi < $n_from - $endskip; $xi++) {
 537                         $line = $from_lines[$xi];
 538                         if ( ($this->xchanged[$xi] = empty($yhash[$line])) )
 539                                 continue;
 540                         $this->xv[] = $line;
 541                         $this->xind[] = $xi;
 542                 }
 543
 544                 // Find the LCS.
 545                 $this->_compareseq(0, sizeof($this->xv), 0, sizeof($this->yv));
 546
 547                 // Merge edits when possible
 548                 $this->_shift_boundaries($from_lines, $this->xchanged, $this->ychanged);
 549                 $this->_shift_boundaries($to_lines, $this->ychanged, $this->xchanged);
 550
 551                 // Compute the edit operations.
 552                 $edits = array();
 553                 $xi = $yi = 0;
 554                 while ($xi < $n_from || $yi < $n_to) {
 555                         USE_ASSERTS && assert($yi < $n_to || $this->xchanged[$xi]);
 556                         USE_ASSERTS && assert($xi < $n_from || $this->ychanged[$yi]);
 557
 558                         // Skip matching "snake".
 559                         $copy = array();
 560                         while ( $xi < $n_from && $yi < $n_to
 561                                         && !$this->xchanged[$xi] && !$this->ychanged[$yi]) {
 562                                 $copy[] = $from_lines[$xi++];
 563                                 ++$yi;
 564                         }
 565                         if ($copy)
 566                                 $edits[] = new _DiffOp_Copy($copy);
 567
 568                         // Find deletes & adds.
 569                         $delete = array();
 570                         while ($xi < $n_from && $this->xchanged[$xi])
 571                                 $delete[] = $from_lines[$xi++];
 572
 573                         $add = array();
 574                         while ($yi < $n_to && $this->ychanged[$yi])
 575                                 $add[] = $to_lines[$yi++];
 576
 577                         if ($delete && $add)
 578                                 $edits[] = new _DiffOp_Change($delete, $add);
 579                         elseif ($delete)
 580                                 $edits[] = new _DiffOp_Delete($delete);
 581                         elseif ($add)
 582                                 $edits[] = new _DiffOp_Add($add);
 583                 }
 584                 wfProfileOut( $fname );
 585                 return $edits;
 586         }
 587
 588
 589         /* Divide the Largest Common Subsequence (LCS) of the sequences
 590          * [XOFF, XLIM) and [YOFF, YLIM) into NCHUNKS approximately equally
 591          * sized segments.
 592          *
 593          * Returns (LCS, PTS).  LCS is the length of the LCS. PTS is an
 594          * array of NCHUNKS+1 (X, Y) indexes giving the diving points between
 595          * sub sequences.  The first sub-sequence is contained in [X0, X1),
 596          * [Y0, Y1), the second in [X1, X2), [Y1, Y2) and so on.  Note
 597          * that (X0, Y0) == (XOFF, YOFF) and
 598          * (X[NCHUNKS], Y[NCHUNKS]) == (XLIM, YLIM).
 599          *
 600          * This function assumes that the first lines of the specified portions
 601          * of the two files do not match, and likewise that the last lines do not
 602          * match.  The caller must trim matching lines from the beginning and end
 603          * of the portions it is going to specify.
 604          */
 605         function _diag ($xoff, $xlim, $yoff, $ylim, $nchunks) {
 606                 $fname = '_DiffEngine::_diag';
 607                 wfProfileIn( $fname );
 608                 $flip = false;
 609
 610                 if ($xlim - $xoff > $ylim - $yoff) {
 611                         // Things seems faster (I'm not sure I understand why)
 612                                 // when the shortest sequence in X.
 613                                 $flip = true;
 614                         list ($xoff, $xlim, $yoff, $ylim)
 615                         = array( $yoff, $ylim, $xoff, $xlim);
 616                 }
 617
 618                 if ($flip)
 619                         for ($i = $ylim - 1; $i >= $yoff; $i--)
 620                                 $ymatches[$this->xv[$i]][] = $i;
 621                 else
 622                         for ($i = $ylim - 1; $i >= $yoff; $i--)
 623                                 $ymatches[$this->yv[$i]][] = $i;
 624
 625                 $this->lcs = 0;
 626                 $this->seq[0]= $yoff - 1;
 627                 $this->in_seq = array();
 628                 $ymids[0] = array();
 629
 630                 $numer = $xlim - $xoff + $nchunks - 1;
 631                 $x = $xoff;
 632                 for ($chunk = 0; $chunk < $nchunks; $chunk++) {
 633                         wfProfileIn( "$fname-chunk" );
 634                         if ($chunk > 0)
 635                                 for ($i = 0; $i <= $this->lcs; $i++)
 636                                         $ymids[$i][$chunk-1] = $this->seq[$i];
 637
 638                         $x1 = $xoff + (int)(($numer + ($xlim-$xoff)*$chunk) / $nchunks);
 639                         for ( ; $x < $x1; $x++) {
 640                                 $line = $flip ? $this->yv[$x] : $this->xv[$x];
 641                                         if (empty($ymatches[$line]))
 642                                                 continue;
 643                                 $matches = $ymatches[$line];
 644                                 reset($matches);
 645                                 while (list ($junk, $y) = each($matches))
 646                                         if (empty($this->in_seq[$y])) {
 647                                                 $k = $this->_lcs_pos($y);
 648                                                 USE_ASSERTS && assert($k > 0);
 649                                                 $ymids[$k] = $ymids[$k-1];
 650                                                 break;
 651                                         }
 652                                 while (list ($junk, $y) = each($matches)) {
 653                                         if ($y > $this->seq[$k-1]) {
 654                                                 USE_ASSERTS && assert($y < $this->seq[$k]);
 655                                                 // Optimization: this is a common case:
 656                                                 //      next match is just replacing previous match.
 657                                                 $this->in_seq[$this->seq[$k]] = false;
 658                                                 $this->seq[$k] = $y;
 659                                                 $this->in_seq[$y] = 1;
 660                                         } else if (empty($this->in_seq[$y])) {
 661                                                 $k = $this->_lcs_pos($y);
 662                                                 USE_ASSERTS && assert($k > 0);
 663                                                 $ymids[$k] = $ymids[$k-1];
 664                                         }
 665                                 }
 666                         }
 667                         wfProfileOut( "$fname-chunk" );
 668                 }
 669
 670                 $seps[] = $flip ? array($yoff, $xoff) : array($xoff, $yoff);
 671                 $ymid = $ymids[$this->lcs];
 672                 for ($n = 0; $n < $nchunks - 1; $n++) {
 673                         $x1 = $xoff + (int)(($numer + ($xlim - $xoff) * $n) / $nchunks);
 674                         $y1 = $ymid[$n] + 1;
 675                         $seps[] = $flip ? array($y1, $x1) : array($x1, $y1);
 676                 }
 677                 $seps[] = $flip ? array($ylim, $xlim) : array($xlim, $ylim);
 678
 679                 wfProfileOut( $fname );
 680                 return array($this->lcs, $seps);
 681         }
 682
 683         function _lcs_pos ($ypos) {
 684                 $fname = '_DiffEngine::_lcs_pos';
 685                 wfProfileIn( $fname );
 686
 687                 $end = $this->lcs;
 688                 if ($end == 0 || $ypos > $this->seq[$end]) {
 689                         $this->seq[++$this->lcs] = $ypos;
 690                         $this->in_seq[$ypos] = 1;
 691                         wfProfileOut( $fname );
 692                         return $this->lcs;
 693                 }
 694
 695                 $beg = 1;
 696                 while ($beg < $end) {
 697                         $mid = (int)(($beg + $end) / 2);
 698                         if ( $ypos > $this->seq[$mid] )
 699                                 $beg = $mid + 1;
 700                         else
 701                                 $end = $mid;
 702                 }
 703
 704                 USE_ASSERTS && assert($ypos != $this->seq[$end]);
 705
 706                 $this->in_seq[$this->seq[$end]] = false;
 707                 $this->seq[$end] = $ypos;
 708                 $this->in_seq[$ypos] = 1;
 709                 wfProfileOut( $fname );
 710                 return $end;
 711         }
 712
 713         /* Find LCS of two sequences.
 714          *
 715          * The results are recorded in the vectors $this->{x,y}changed[], by
 716          * storing a 1 in the element for each line that is an insertion
 717          * or deletion (ie. is not in the LCS).
 718          *
 719          * The subsequence of file 0 is [XOFF, XLIM) and likewise for file 1.
 720          *
 721          * Note that XLIM, YLIM are exclusive bounds.
 722          * All line numbers are origin-0 and discarded lines are not counted.
 723          */
 724         function _compareseq ($xoff, $xlim, $yoff, $ylim) {
 725                 $fname = '_DiffEngine::_compareseq';
 726                 wfProfileIn( $fname );
 727
 728                 // Slide down the bottom initial diagonal.
 729                 while ($xoff < $xlim && $yoff < $ylim
 730                            && $this->xv[$xoff] == $this->yv[$yoff]) {
 731                         ++$xoff;
 732                         ++$yoff;
 733                 }
 734
 735                 // Slide up the top initial diagonal.
 736                 while ($xlim > $xoff && $ylim > $yoff
 737                            && $this->xv[$xlim - 1] == $this->yv[$ylim - 1]) {
 738                         --$xlim;
 739                         --$ylim;
 740                 }
 741
 742                 if ($xoff == $xlim || $yoff == $ylim)
 743                         $lcs = 0;
 744                 else {
 745                         // This is ad hoc but seems to work well.
 746                         //$nchunks = sqrt(min($xlim - $xoff, $ylim - $yoff) / 2.5);
 747                         //$nchunks = max(2,min(8,(int)$nchunks));
 748                         $nchunks = min(7, $xlim - $xoff, $ylim - $yoff) + 1;
 749                         list ($lcs, $seps)
 750                         = $this->_diag($xoff,$xlim,$yoff, $ylim,$nchunks);
 751                 }
 752
 753                 if ($lcs == 0) {
 754                         // X and Y sequences have no common subsequence:
 755                         // mark all changed.
 756                         while ($yoff < $ylim)
 757                                 $this->ychanged[$this->yind[$yoff++]] = 1;
 758                         while ($xoff < $xlim)
 759                                 $this->xchanged[$this->xind[$xoff++]] = 1;
 760                 } else {
 761                         // Use the partitions to split this problem into subproblems.
 762                         reset($seps);
 763                         $pt1 = $seps[0];
 764                         while ($pt2 = next($seps)) {
 765                                 $this->_compareseq ($pt1[0], $pt2[0], $pt1[1], $pt2[1]);
 766                                 $pt1 = $pt2;
 767                         }
 768                 }
 769                 wfProfileOut( $fname );
 770         }
 771
 772         /* Adjust inserts/deletes of identical lines to join changes
 773          * as much as possible.
 774          *
 775          * We do something when a run of changed lines include a
 776          * line at one end and has an excluded, identical line at the other.
 777          * We are free to choose which identical line is included.
 778          * `compareseq' usually chooses the one at the beginning,
 779          * but usually it is cleaner to consider the following identical line
 780          * to be the "change".
 781          *
 782          * This is extracted verbatim from analyze.c (GNU diffutils-2.7).
 783          */
 784         function _shift_boundaries ($lines, &$changed, $other_changed) {
 785                 $fname = '_DiffEngine::_shift_boundaries';
 786                 wfProfileIn( $fname );
 787                 $i = 0;
 788                 $j = 0;
 789
 790                 USE_ASSERTS && assert('sizeof($lines) == sizeof($changed)');
 791                 $len = sizeof($lines);
 792                 $other_len = sizeof($other_changed);
 793
 794                 while (1) {
 795                         /*
 796                          * Scan forwards to find beginning of another run of changes.
 797                          * Also keep track of the corresponding point in the other file.
 798                          *
 799                          * Throughout this code, $i and $j are adjusted together so that
 800                          * the first $i elements of $changed and the first $j elements
 801                          * of $other_changed both contain the same number of zeros
 802                          * (unchanged lines).
 803                          * Furthermore, $j is always kept so that $j == $other_len or
 804                          * $other_changed[$j] == false.
 805                          */
 806                         while ($j < $other_len && $other_changed[$j])
 807                                 $j++;
 808
 809                         while ($i < $len && ! $changed[$i]) {
 810                                 USE_ASSERTS && assert('$j < $other_len && ! $other_changed[$j]');
 811                                 $i++; $j++;
 812                                 while ($j < $other_len && $other_changed[$j])
 813                                         $j++;
 814                         }
 815
 816                         if ($i == $len)
 817                                 break;
 818
 819                         $start = $i;
 820
 821                         // Find the end of this run of changes.
 822                         while (++$i < $len && $changed[$i])
 823                                 continue;
 824
 825                         do {
 826                                 /*
 827                                  * Record the length of this run of changes, so that
 828                                  * we can later determine whether the run has grown.
 829                                  */
 830                                 $runlength = $i - $start;
 831
 832                                 /*
 833                                  * Move the changed region back, so long as the
 834                                  * previous unchanged line matches the last changed one.
 835                                  * This merges with previous changed regions.
 836                                  */
 837                                 while ($start > 0 && $lines[$start - 1] == $lines[$i - 1]) {
 838                                         $changed[--$start] = 1;
 839                                         $changed[--$i] = false;
 840                                         while ($start > 0 && $changed[$start - 1])
 841                                                 $start--;
 842                                         USE_ASSERTS && assert('$j > 0');
 843                                         while ($other_changed[--$j])
 844                                                 continue;
 845                                         USE_ASSERTS && assert('$j >= 0 && !$other_changed[$j]');
 846                                 }
 847
 848                                 /*
 849                                  * Set CORRESPONDING to the end of the changed run, at the last
 850                                  * point where it corresponds to a changed run in the other file.
 851                                  * CORRESPONDING == LEN means no such point has been found.
 852                                  */
 853                                 $corresponding = $j < $other_len ? $i : $len;
 854
 855                                 /*
 856                                  * Move the changed region forward, so long as the
 857                                  * first changed line matches the following unchanged one.
 858                                  * This merges with following changed regions.
 859                                  * Do this second, so that if there are no merges,
 860                                  * the changed region is moved forward as far as possible.
 861                                  */
 862                                 while ($i < $len && $lines[$start] == $lines[$i]) {
 863                                         $changed[$start++] = false;
 864                                         $changed[$i++] = 1;
 865                                         while ($i < $len && $changed[$i])
 866                                                 $i++;
 867
 868                                         USE_ASSERTS && assert('$j < $other_len && ! $other_changed[$j]');
 869                                         $j++;
 870                                         if ($j < $other_len && $other_changed[$j]) {
 871                                                 $corresponding = $i;
 872                                                 while ($j < $other_len && $other_changed[$j])
 873                                                         $j++;
 874                                         }
 875                                 }
 876                         } while ($runlength != $i - $start);
 877
 878                         /*
 879                          * If possible, move the fully-merged run of changes
 880                          * back to a corresponding run in the other file.
 881                          */
 882                         while ($corresponding < $i) {
 883                                 $changed[--$start] = 1;
 884                                 $changed[--$i] = 0;
 885                                 USE_ASSERTS && assert('$j > 0');
 886                                 while ($other_changed[--$j])
 887                                         continue;
 888                                 USE_ASSERTS && assert('$j >= 0 && !$other_changed[$j]');
 889                         }
 890                 }
 891                 wfProfileOut( $fname );
 892         }
 893 }
 894
 895 /**
 896  * Class representing a 'diff' between two sequences of strings.
 897  * @todo document
 898  * @access private
 899  * @package MediaWiki
 900  * @subpackage DifferenceEngine
 901  */
 902 class Diff
 903 {
 904         var $edits;
 905
 906         /**
 907          * Constructor.
 908          * Computes diff between sequences of strings.
 909          *
 910          * @param $from_lines array An array of strings.
 911          *                (Typically these are lines from a file.)
 912          * @param $to_lines array An array of strings.
 913          */
 914         function Diff($from_lines, $to_lines) {
 915                 $eng = new _DiffEngine;
 916                 $this->edits = $eng->diff($from_lines, $to_lines);
 917                 //$this->_check($from_lines, $to_lines);
 918         }
 919
 920         /**
 921          * Compute reversed Diff.
 922          *
 923          * SYNOPSIS:
 924          *
 925          *      $diff = new Diff($lines1, $lines2);
 926          *      $rev = $diff->reverse();
 927          * @return object A Diff object representing the inverse of the
 928          *                                original diff.
 929          */
 930         function reverse () {
 931                 $rev = $this;
 932                 $rev->edits = array();
 933                 foreach ($this->edits as $edit) {
 934                         $rev->edits[] = $edit->reverse();
 935                 }
 936                 return $rev;
 937         }
 938
 939         /**
 940          * Check for empty diff.
 941          *
 942          * @return bool True iff two sequences were identical.
 943          */
 944         function isEmpty () {
 945                 foreach ($this->edits as $edit) {
 946                         if ($edit->type != 'copy')
 947                                 return false;
 948                 }
 949                 return true;
 950         }
 951
 952         /**
 953          * Compute the length of the Longest Common Subsequence (LCS).
 954          *
 955          * This is mostly for diagnostic purposed.
 956          *
 957          * @return int The length of the LCS.
 958          */
 959         function lcs () {
 960                 $lcs = 0;
 961                 foreach ($this->edits as $edit) {
 962                         if ($edit->type == 'copy')
 963                                 $lcs += sizeof($edit->orig);
 964                 }
 965                 return $lcs;
 966         }
 967
 968         /**
 969          * Get the original set of lines.
 970          *
 971          * This reconstructs the $from_lines parameter passed to the
 972          * constructor.
 973          *
 974          * @return array The original sequence of strings.
 975          */
 976         function orig() {
 977                 $lines = array();
 978
 979                 foreach ($this->edits as $edit) {
 980                         if ($edit->orig)
 981                                 array_splice($lines, sizeof($lines), 0, $edit->orig);
 982                 }
 983                 return $lines;
 984         }
 985
 986         /**
 987          * Get the closing set of lines.
 988          *
 989          * This reconstructs the $to_lines parameter passed to the
 990          * constructor.
 991          *
 992          * @return array The sequence of strings.
 993          */
 994         function closing() {
 995                 $lines = array();
 996
 997                 foreach ($this->edits as $edit) {
 998                         if ($edit->closing)
 999                                 array_splice($lines, sizeof($lines), 0, $edit->closing);
1000                 }
1001                 return $lines;
1002         }
1003
1004         /**
1005          * Check a Diff for validity.
1006          *
1007          * This is here only for debugging purposes.
1008          */
1009         function _check ($from_lines, $to_lines) {
1010                 $fname = 'Diff::_check';
1011                 wfProfileIn( $fname );
1012                 if (serialize($from_lines) != serialize($this->orig()))
1013                         trigger_error("Reconstructed original doesn't match", E_USER_ERROR);
1014                 if (serialize($to_lines) != serialize($this->closing()))
1015                         trigger_error("Reconstructed closing doesn't match", E_USER_ERROR);
1016
1017                 $rev = $this->reverse();
1018                 if (serialize($to_lines) != serialize($rev->orig()))
1019                         trigger_error("Reversed original doesn't match", E_USER_ERROR);
1020                 if (serialize($from_lines) != serialize($rev->closing()))
1021                         trigger_error("Reversed closing doesn't match", E_USER_ERROR);
1022
1023
1024                 $prevtype = 'none';
1025                 foreach ($this->edits as $edit) {
1026                         if ( $prevtype == $edit->type )
1027                                 trigger_error("Edit sequence is non-optimal", E_USER_ERROR);
1028                         $prevtype = $edit->type;
1029                 }
1030
1031                 $lcs = $this->lcs();
1032                 trigger_error('Diff okay: LCS = '.$lcs, E_USER_NOTICE);
1033                 wfProfileOut( $fname );
1034         }
1035 }
1036
1037 /**
1038  * FIXME: bad name.
1039  * @todo document
1040  * @access private
1041  * @package MediaWiki
1042  * @subpackage DifferenceEngine
1043  */
1044 class MappedDiff extends Diff
1045 {
1046         /**
1047          * Constructor.
1048          *
1049          * Computes diff between sequences of strings.
1050          *
1051          * This can be used to compute things like
1052          * case-insensitve diffs, or diffs which ignore
1053          * changes in white-space.
1054          *
1055          * @param $from_lines array An array of strings.
1056          *      (Typically these are lines from a file.)
1057          *
1058          * @param $to_lines array An array of strings.
1059          *
1060          * @param $mapped_from_lines array This array should
1061          *      have the same size number of elements as $from_lines.
1062          *      The elements in $mapped_from_lines and
1063          *      $mapped_to_lines are what is actually compared
1064          *      when computing the diff.
1065          *
1066          * @param $mapped_to_lines array This array should
1067          *      have the same number of elements as $to_lines.
1068          */
1069         function MappedDiff($from_lines, $to_lines,
1070                                                 $mapped_from_lines, $mapped_to_lines) {
1071                 $fname = 'MappedDiff::MappedDiff';
1072                 wfProfileIn( $fname );
1073
1074                 assert(sizeof($from_lines) == sizeof($mapped_from_lines));
1075                 assert(sizeof($to_lines) == sizeof($mapped_to_lines));
1076
1077                 $this->Diff($mapped_from_lines, $mapped_to_lines);
1078
1079                 $xi = $yi = 0;
1080                 for ($i = 0; $i < sizeof($this->edits); $i++) {
1081                         $orig = &$this->edits[$i]->orig;
1082                         if (is_array($orig)) {
1083                                 $orig = array_slice($from_lines, $xi, sizeof($orig));
1084                                 $xi += sizeof($orig);
1085                         }
1086
1087                         $closing = &$this->edits[$i]->closing;
1088                         if (is_array($closing)) {
1089                                 $closing = array_slice($to_lines, $yi, sizeof($closing));
1090                                 $yi += sizeof($closing);
1091                         }
1092                 }
1093                 wfProfileOut( $fname );
1094         }
1095 }
1096
1097 /**
1098  * A class to format Diffs
1099  *
1100  * This class formats the diff in classic diff format.
1101  * It is intended that this class be customized via inheritance,
1102  * to obtain fancier outputs.
1103  * @todo document
1104  * @access private
1105  * @package MediaWiki
1106  * @subpackage DifferenceEngine
1107  */
1108 class DiffFormatter
1109 {
1110         /**
1111          * Number of leading 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 $leading_context_lines = 0;
1117
1118         /**
1119          * Number of trailing context "lines" to preserve.
1120          *
1121          * This should be left at zero for this class, but subclasses
1122          * may want to set this to other values.
1123          */
1124         var $trailing_context_lines = 0;
1125
1126         /**
1127          * Format a diff.
1128          *
1129          * @param $diff object A Diff object.
1130          * @return string The formatted output.
1131          */
1132         function format($diff) {
1133                 $fname = 'DiffFormatter::format';
1134                 wfProfileIn( $fname );
1135
1136                 $xi = $yi = 1;
1137                 $block = false;
1138                 $context = array();
1139
1140                 $nlead = $this->leading_context_lines;
1141                 $ntrail = $this->trailing_context_lines;
1142
1143                 $this->_start_diff();
1144
1145                 foreach ($diff->edits as $edit) {
1146                         if ($edit->type == 'copy') {
1147                                 if (is_array($block)) {
1148                                         if (sizeof($edit->orig) <= $nlead + $ntrail) {
1149                                                 $block[] = $edit;
1150                                         }
1151                                         else{
1152                                                 if ($ntrail) {
1153                                                         $context = array_slice($edit->orig, 0, $ntrail);
1154                                                         $block[] = new _DiffOp_Copy($context);
1155                                                 }
1156                                                 $this->_block($x0, $ntrail + $xi - $x0,
1157                                                                           $y0, $ntrail + $yi - $y0,
1158                                                                           $block);
1159                                                 $block = false;
1160                                         }
1161                                 }
1162                                 $context = $edit->orig;
1163                         }
1164                         else {
1165                                 if (! is_array($block)) {
1166                                         $context = array_slice($context, sizeof($context) - $nlead);
1167                                         $x0 = $xi - sizeof($context);
1168                                         $y0 = $yi - sizeof($context);
1169                                         $block = array();
1170                                         if ($context)
1171                                                 $block[] = new _DiffOp_Copy($context);
1172                                 }
1173                                 $block[] = $edit;
1174                         }
1175
1176                         if ($edit->orig)
1177                                 $xi += sizeof($edit->orig);
1178                         if ($edit->closing)
1179                                 $yi += sizeof($edit->closing);
1180                 }
1181
1182                 if (is_array($block))
1183                         $this->_block($x0, $xi - $x0,
1184                                                   $y0, $yi - $y0,
1185                                                   $block);
1186
1187                 $end = $this->_end_diff();
1188                 wfProfileOut( $fname );
1189                 return $end;
1190         }
1191
1192         function _block($xbeg, $xlen, $ybeg, $ylen, &$edits) {
1193                 $fname = 'DiffFormatter::_block';
1194                 wfProfileIn( $fname );
1195                 $this->_start_block($this->_block_header($xbeg, $xlen, $ybeg, $ylen));
1196                 foreach ($edits as $edit) {
1197                         if ($edit->type == 'copy')
1198                                 $this->_context($edit->orig);
1199                         elseif ($edit->type == 'add')
1200                                 $this->_added($edit->closing);
1201                         elseif ($edit->type == 'delete')
1202                                 $this->_deleted($edit->orig);
1203                         elseif ($edit->type == 'change')
1204                                 $this->_changed($edit->orig, $edit->closing);
1205                         else
1206                                 trigger_error('Unknown edit type', E_USER_ERROR);
1207                 }
1208                 $this->_end_block();
1209                 wfProfileOut( $fname );
1210         }
1211
1212         function _start_diff() {
1213                 ob_start();
1214         }
1215
1216         function _end_diff() {
1217                 $val = ob_get_contents();
1218                 ob_end_clean();
1219                 return $val;
1220         }
1221
1222         function _block_header($xbeg, $xlen, $ybeg, $ylen) {
1223                 if ($xlen > 1)
1224                         $xbeg .= "," . ($xbeg + $xlen - 1);
1225                 if ($ylen > 1)
1226                         $ybeg .= "," . ($ybeg + $ylen - 1);
1227
1228                 return $xbeg . ($xlen ? ($ylen ? 'c' : 'd') : 'a') . $ybeg;
1229         }
1230
1231         function _start_block($header) {
1232                 echo $header;
1233         }
1234
1235         function _end_block() {
1236         }
1237
1238         function _lines($lines, $prefix = ' ') {
1239                 foreach ($lines as $line)
1240                         echo "$prefix $line\n";
1241         }
1242
1243         function _context($lines) {
1244                 $this->_lines($lines);
1245         }
1246
1247         function _added($lines) {
1248                 $this->_lines($lines, '>');
1249         }
1250         function _deleted($lines) {
1251                 $this->_lines($lines, '<');
1252         }
1253
1254         function _changed($orig, $closing) {
1255                 $this->_deleted($orig);
1256                 echo "---\n";
1257                 $this->_added($closing);
1258         }
1259 }
1260
1261
1262 /**
1263  *      Additions by Axel Boldt follow, partly taken from diff.php, phpwiki-1.3.3
1264  *
1265  */
1266
1267 define('NBSP', '&#160;');                       // iso-8859-x non-breaking space.
1268
1269 /**
1270  * @todo document
1271  * @access private
1272  * @package MediaWiki
1273  * @subpackage DifferenceEngine
1274  */
1275 class _HWLDF_WordAccumulator {
1276         function _HWLDF_WordAccumulator () {
1277                 $this->_lines = array();
1278                 $this->_line = '';
1279                 $this->_group = '';
1280                 $this->_tag = '';
1281         }
1282
1283         function _flushGroup ($new_tag) {
1284                 if ($this->_group !== '') {
1285                         if ($this->_tag == 'mark')
1286                                 $this->_line .= '<span class="diffchange">' .
1287                                         htmlspecialchars ( $this->_group ) . '</span>';
1288                         else
1289                                 $this->_line .= htmlspecialchars ( $this->_group );
1290                 }
1291                 $this->_group = '';
1292                 $this->_tag = $new_tag;
1293         }
1294
1295         function _flushLine ($new_tag) {
1296                 $this->_flushGroup($new_tag);
1297                 if ($this->_line != '')
1298                         array_push ( $this->_lines, $this->_line );
1299                 else
1300                         # make empty lines visible by inserting an NBSP
1301                         array_push ( $this->_lines, NBSP );
1302                 $this->_line = '';
1303         }
1304
1305         function addWords ($words, $tag = '') {
1306                 if ($tag != $this->_tag)
1307                         $this->_flushGroup($tag);
1308
1309                 foreach ($words as $word) {
1310                         // new-line should only come as first char of word.
1311                         if ($word == '')
1312                                 continue;
1313                         if ($word[0] == "\n") {
1314                                 $this->_flushLine($tag);
1315                                 $word = substr($word, 1);
1316                         }
1317                         assert(!strstr($word, "\n"));
1318                         $this->_group .= $word;
1319                 }
1320         }
1321
1322         function getLines() {
1323                 $this->_flushLine('~done');
1324                 return $this->_lines;
1325         }
1326 }
1327
1328 /**
1329  * @todo document
1330  * @access private
1331  * @package MediaWiki
1332  * @subpackage DifferenceEngine
1333  */
1334 class WordLevelDiff extends MappedDiff
1335 {
1336         function WordLevelDiff ($orig_lines, $closing_lines) {
1337                 $fname = 'WordLevelDiff::WordLevelDiff';
1338                 wfProfileIn( $fname );
1339
1340                 list ($orig_words, $orig_stripped) = $this->_split($orig_lines);
1341                 list ($closing_words, $closing_stripped) = $this->_split($closing_lines);
1342
1343
1344                 $this->MappedDiff($orig_words, $closing_words,
1345                                                   $orig_stripped, $closing_stripped);
1346                 wfProfileOut( $fname );
1347         }
1348
1349         function _split($lines) {
1350                 $fname = 'WordLevelDiff::_split';
1351                 wfProfileIn( $fname );
1352                 if (!preg_match_all('/ ( [^\S\n]+ | [0-9_A-Za-z\x80-\xff]+ | . ) (?: (?!< \n) [^\S\n])? /xs',
1353                                                         implode("\n", $lines),
1354                                                         $m)) {
1355                         wfProfileOut( $fname );
1356                         return array(array(''), array(''));
1357                 }
1358                 wfProfileOut( $fname );
1359                 return array($m[0], $m[1]);
1360         }
1361
1362         function orig () {
1363                 $fname = 'WordLevelDiff::orig';
1364                 wfProfileIn( $fname );
1365                 $orig = new _HWLDF_WordAccumulator;
1366
1367                 foreach ($this->edits as $edit) {
1368                         if ($edit->type == 'copy')
1369                                 $orig->addWords($edit->orig);
1370                         elseif ($edit->orig)
1371                                 $orig->addWords($edit->orig, 'mark');
1372                 }
1373                 $lines = $orig->getLines();
1374                 wfProfileOut( $fname );
1375                 return $lines;
1376         }
1377
1378         function closing () {
1379                 $fname = 'WordLevelDiff::closing';
1380                 wfProfileIn( $fname );
1381                 $closing = new _HWLDF_WordAccumulator;
1382
1383                 foreach ($this->edits as $edit) {
1384                         if ($edit->type == 'copy')
1385                                 $closing->addWords($edit->closing);
1386                         elseif ($edit->closing)
1387                                 $closing->addWords($edit->closing, 'mark');
1388                 }
1389                 $lines = $closing->getLines();
1390                 wfProfileOut( $fname );
1391                 return $lines;
1392         }
1393 }
1394
1395 /**
1396  *      Wikipedia Table style diff formatter.
1397  * @todo document
1398  * @access private
1399  * @package MediaWiki
1400  * @subpackage DifferenceEngine
1401  */
1402 class TableDiffFormatter extends DiffFormatter
1403 {
1404         function TableDiffFormatter() {
1405                 $this->leading_context_lines = 2;
1406                 $this->trailing_context_lines = 2;
1407         }
1408
1409         function _block_header( $xbeg, $xlen, $ybeg, $ylen ) {
1410                 $l1 = wfMsg( 'lineno', $xbeg );
1411                 $l2 = wfMsg( 'lineno', $ybeg );
1412
1413                 $r = '<tr><td colspan="2" align="left"><strong>'.$l1."</strong></td>\n" .
1414                   '<td colspan="2" align="left"><strong>'.$l2."</strong></td></tr>\n";
1415                 return $r;
1416         }
1417
1418         function _start_block( $header ) {
1419                 global $wgOut;
1420                 echo $header;
1421         }
1422
1423         function _end_block() {
1424         }
1425
1426         function _lines( $lines, $prefix=' ', $color='white' ) {
1427         }
1428
1429         # HTML-escape parameter before calling this
1430         function addedLine( $line ) {
1431                 return "<td>+</td><td class='diff-addedline'>{$line}</td>";
1432         }
1433
1434         # HTML-escape parameter before calling this
1435         function deletedLine( $line ) {
1436                 return "<td>-</td><td class='diff-deletedline'>{$line}</td>";
1437         }
1438
1439         # HTML-escape parameter before calling this
1440         function contextLine( $line ) {
1441                 return "<td> </td><td class='diff-context'>{$line}</td>";
1442         }
1443
1444         function emptyLine() {
1445                 return '<td colspan="2">&nbsp;</td>';
1446         }
1447
1448         function _added( $lines ) {
1449                 foreach ($lines as $line) {
1450                         echo '<tr>' . $this->emptyLine() .
1451                                 $this->addedLine( htmlspecialchars ( $line ) ) . "</tr>\n";
1452                 }
1453         }
1454
1455         function _deleted($lines) {
1456                 foreach ($lines as $line) {
1457                         echo '<tr>' . $this->deletedLine( htmlspecialchars ( $line ) ) .
1458                           $this->emptyLine() . "</tr>\n";
1459                 }
1460         }
1461
1462         function _context( $lines ) {
1463                 foreach ($lines as $line) {
1464                         echo '<tr>' .
1465                                 $this->contextLine( htmlspecialchars ( $line ) ) .
1466                                 $this->contextLine( htmlspecialchars ( $line ) ) . "</tr>\n";
1467                 }
1468         }
1469
1470         function _changed( $orig, $closing ) {
1471                 $fname = 'TableDiffFormatter::_changed';
1472                 wfProfileIn( $fname );
1473
1474                 $diff = new WordLevelDiff( $orig, $closing );
1475                 $del = $diff->orig();
1476                 $add = $diff->closing();
1477
1478                 # Notice that WordLevelDiff returns HTML-escaped output.
1479                 # Hence, we will be calling addedLine/deletedLine without HTML-escaping.
1480
1481                 while ( $line = array_shift( $del ) ) {
1482                         $aline = array_shift( $add );
1483                         echo '<tr>' . $this->deletedLine( $line ) .
1484                                 $this->addedLine( $aline ) . "</tr>\n";
1485                 }
1486                 foreach ($add as $line) {       # If any leftovers
1487                         echo '<tr>' . $this->emptyLine() .
1488                                 $this->addedLine( $line ) . "</tr>\n";
1489                 }
1490                 wfProfileOut( $fname );
1491         }
1492 }
1493
1494 ?>