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 define( 'MAX_DIFF_LINE', 10000 );
  12 define( 'MAX_DIFF_XREF_LENGTH', 10000 );
  13
  14 /**
  15  * @todo document
  16  * @access public
  17  * @package MediaWiki
  18  * @subpackage DifferenceEngine
  19  */
  20 class DifferenceEngine {
  21         /**#@+
  22          * @access private
  23          */
  24         var $mOldid, $mNewid;
  25         var $mOldtitle, $mNewtitle, $mPagetitle;
  26         var $mOldtext, $mNewtext;
  27         var $mOldUser, $mNewUser;
  28         var $mOldComment, $mNewComment;
  29         var $mOldPage, $mNewPage;
  30         var $mRcidMarkPatrolled;
  31         /**#@-*/
  32
  33         /**
  34          * Constructor
  35          * @param integer $old Old ID we want to show and diff with.
  36          * @param string $new Either 'prev' or 'next'.
  37          * @param integer $rcid ??? (default 0)
  38          */
  39         function DifferenceEngine( $old, $new, $rcid = 0 ) {
  40                 global $wgTitle;
  41
  42                 if ( 'prev' == $new ) {
  43                         # Show diff between revision $old and the previous one.
  44                         # Get previous one from DB.
  45                         #
  46                         $this->mNewid = intval($old);
  47
  48                         $this->mOldid = $wgTitle->getPreviousRevisionID( $this->mNewid );
  49
  50                 } elseif ( 'next' == $new ) {
  51                         # Show diff between revision $old and the previous one.
  52                         # Get previous one from DB.
  53                         #
  54                         $this->mOldid = intval($old);
  55                         $this->mNewid = $wgTitle->getNextRevisionID( $this->mOldid );
  56                         if ( false === $this->mNewid ) {
  57                                 # if no result, NewId points to the newest old revision. The only newer
  58                                 # revision is cur, which is "0".
  59                                 $this->mNewid = 0;
  60                         }
  61
  62                 } else {
  63                         $this->mOldid = intval($old);
  64                         $this->mNewid = intval($new);
  65                 }
  66                 $this->mRcidMarkPatrolled = intval($rcid);  # force it to be an integer
  67         }
  68
  69         function showDiffPage() {
  70                 global $wgUser, $wgTitle, $wgOut, $wgContLang, $wgOnlySysopsCanPatrol,
  71                        $wgUseExternalEditor, $wgUseRCPatrol;
  72                 $fname = 'DifferenceEngine::showDiffPage';
  73                 wfProfileIn( $fname );
  74
  75                 # If external diffs are enabled both globally and for the user,
  76                 # we'll use the application/x-external-editor interface to call
  77                 # an external diff tool like kompare, kdiff3, etc.
  78                 if($wgUseExternalEditor && $wgUser->getOption('externaldiff')) {
  79                         global $wgInputEncoding,$wgServer,$wgScript,$wgLang;
  80                         $wgOut->disable();
  81                         header ( "Content-type: application/x-external-editor; charset=".$wgInputEncoding );
  82                         $url1=$wgTitle->getFullURL("action=raw&oldid=".$this->mOldid);
  83                         $url2=$wgTitle->getFullURL("action=raw&oldid=".$this->mNewid);
  84                         $special=$wgLang->getNsText(NS_SPECIAL);
  85                         $control=<<<CONTROL
  86 [Process]
  87 Type=Diff text
  88 Engine=MediaWiki
  89 Script={$wgServer}{$wgScript}
  90 Special namespace={$special}
  91
  92 [File]
  93 Extension=wiki
  94 URL=$url1
  95
  96 [File 2]
  97 Extension=wiki
  98 URL=$url2
  99 CONTROL;
 100                         echo($control);
 101                         return;
 102                 }
 103
 104                 # mOldid is false if the difference engine is called with a "vague" query for
 105                 # a diff between a version V and its previous version V' AND the version V
 106                 # is the first version of that article. In that case, V' does not exist.
 107                 if ( $this->mOldid === false ) {
 108                         $this->showFirstRevision();
 109                         wfProfileOut( $fname );
 110                         return;
 111                 }
 112
 113                 $t = $wgTitle->getPrefixedText() . " (Diff: {$this->mOldid}, " .
 114                   "{$this->mNewid})";
 115                 $mtext = wfMsg( 'missingarticle', $t );
 116
 117                 $wgOut->setArticleFlag( false );
 118                 if ( ! $this->loadText() ) {
 119                         $wgOut->setPagetitle( wfMsg( 'errorpagetitle' ) );
 120                         $wgOut->addHTML( $mtext );
 121                         wfProfileOut( $fname );
 122                         return;
 123                 }
 124                 $wgOut->suppressQuickbar();
 125
 126                 $oldTitle = $this->mOldPage->getPrefixedText();
 127                 $newTitle = $this->mNewPage->getPrefixedText();
 128                 if( $oldTitle == $newTitle ) {
 129                         $wgOut->setPageTitle( $newTitle );
 130                 } else {
 131                         $wgOut->setPageTitle( $oldTitle . ', ' . $newTitle );
 132                 }
 133                 $wgOut->setSubtitle( wfMsg( 'difference' ) );
 134                 $wgOut->setRobotpolicy( 'noindex,follow' );
 135
 136                 if ( !( $this->mOldPage->userCanRead() && $this->mNewPage->userCanRead() ) ) {
 137                         $wgOut->loginToUse();
 138                         $wgOut->output();
 139                         wfProfileOut( $fname );
 140                         exit;
 141                 }
 142
 143                 $sk = $wgUser->getSkin();
 144                 $talk = $wgContLang->getNsText( NS_TALK );
 145                 $contribs = wfMsg( 'contribslink' );
 146
 147                 $this->mOldComment = $sk->formatComment($this->mOldComment);
 148                 $this->mNewComment = $sk->formatComment($this->mNewComment);
 149
 150                 $oldUserLink = $sk->makeLinkObj( Title::makeTitleSafe( NS_USER, $this->mOldUser ), $this->mOldUser );
 151                 $newUserLink = $sk->makeLinkObj( Title::makeTitleSafe( NS_USER, $this->mNewUser ), $this->mNewUser );
 152                 $oldUTLink = $sk->makeLinkObj( Title::makeTitleSafe( NS_USER_TALK, $this->mOldUser ), $talk );
 153                 $newUTLink = $sk->makeLinkObj( Title::makeTitleSafe( NS_USER_TALK, $this->mNewUser ), $talk );
 154                 $oldContribs = $sk->makeKnownLinkObj( Title::makeTitle( NS_SPECIAL, 'Contributions' ), $contribs,
 155                         'target=' . urlencode($this->mOldUser) );
 156                 $newContribs = $sk->makeKnownLinkObj( Title::makeTitle( NS_SPECIAL, 'Contributions' ), $contribs,
 157                         'target=' . urlencode($this->mNewUser) );
 158                 if ( $this->newRev->isCurrent() && $wgUser->isAllowed('rollback') ) {
 159                         $rollback = '&nbsp;&nbsp;&nbsp;<strong>[' . $sk->makeKnownLinkObj( $wgTitle, wfMsg( 'rollbacklink' ),
 160                                 'action=rollback&from=' . urlencode($this->mNewUser) .
 161                                 '&token=' . urlencode( $wgUser->editToken( array( $wgTitle->getPrefixedText(), $this->mNewUser ) ) ) ) .
 162                                 ']</strong>';
 163                 } else {
 164                         $rollback = '';
 165                 }
 166                 if ( $wgUseRCPatrol && $this->mRcidMarkPatrolled != 0 && $wgUser->isLoggedIn() &&
 167                      ( $wgUser->isAllowed('rollback') || !$wgOnlySysopsCanPatrol ) )
 168                 {
 169                         $patrol = ' [' . $sk->makeKnownLinkObj( $wgTitle, wfMsg( 'markaspatrolleddiff' ),
 170                                 "action=markpatrolled&rcid={$this->mRcidMarkPatrolled}" ) . ']';
 171                 } else {
 172                         $patrol = '';
 173                 }
 174
 175                 $prevlink = $sk->makeKnownLinkObj( $wgTitle, wfMsgHtml( 'previousdiff' ),
 176                         'diff=prev&oldid='.$this->mOldid, '', '', 'id="differences-prevlink"' );
 177                 if ( $this->newRev->isCurrent() ) {
 178                         $nextlink = '';
 179                 } else {
 180                         $nextlink = $sk->makeKnownLinkObj( $wgTitle, wfMsgHtml( 'nextdiff' ),
 181                                 'diff=next&oldid='.$this->mNewid, '', '', 'id="differences-nextlink"' );
 182                 }
 183
 184                 $oldHeader = "<strong>{$this->mOldtitle}</strong><br />$oldUserLink " .
 185                         "($oldUTLink | $oldContribs)<br />" . $this->mOldComment .
 186                         '<br />' . $prevlink;
 187                 $newHeader = "<strong>{$this->mNewtitle}</strong><br />$newUserLink " .
 188                         "($newUTLink | $newContribs) $rollback<br />" . $this->mNewComment .
 189                         '<br />' . $nextlink . $patrol;
 190
 191                 DifferenceEngine::showDiff( $this->mOldtext, $this->mNewtext,
 192                   $oldHeader, $newHeader );
 193                 $wgOut->addHTML( "<hr /><h2>{$this->mPagetitle}</h2>\n" );
 194
 195                 if( !$this->newRev->isCurrent() ) {
 196                         $oldEditSectionSetting = $wgOut->mParserOptions->setEditSection( false );
 197                 }
 198                 $wgOut->addWikiText( $this->mNewtext );
 199                 if( !$this->newRev->isCurrent() ) {
 200                         $wgOut->mParserOptions->setEditSection( $oldEditSectionSetting );
 201                 }
 202
 203                 wfProfileOut( $fname );
 204         }
 205
 206         /**
 207          * Show the first revision of an article. Uses normal diff headers in
 208          * contrast to normal "old revision" display style.
 209          */
 210         function showFirstRevision() {
 211                 global $wgOut, $wgTitle, $wgUser, $wgLang;
 212
 213                 $fname = 'DifferenceEngine::showFirstRevision';
 214                 wfProfileIn( $fname );
 215
 216
 217                 $this->mOldid = $this->mNewid; # hack to make loadText() work.
 218
 219                 # Get article text from the DB
 220                 #
 221                 if ( ! $this->loadText() ) {
 222                         $t = $wgTitle->getPrefixedText() . " (Diff: {$this->mOldid}, " .
 223                           "{$this->mNewid})";
 224                         $mtext = wfMsg( 'missingarticle', $t );
 225                         $wgOut->setPagetitle( wfMsg( 'errorpagetitle' ) );
 226                         $wgOut->addHTML( $mtext );
 227                         wfProfileOut( $fname );
 228                         return;
 229                 }
 230
 231                 # Check if user is allowed to look at this page. If not, bail out.
 232                 #
 233                 if ( !( $this->mOldPage->userCanRead() ) ) {
 234                         $wgOut->loginToUse();
 235                         $wgOut->output();
 236                         wfProfileOut( $fname );
 237                         exit;
 238                 }
 239
 240                 # Prepare the header box
 241                 #
 242                 $sk = $wgUser->getSkin();
 243
 244                 $uTLink = $sk->makeLinkObj( Title::makeTitleSafe( NS_USER_TALK, $this->mOldUser ),  $wgLang->getNsText( NS_TALK ) );
 245                 $userLink = $sk->makeLinkObj( Title::makeTitleSafe( NS_USER, $this->mOldUser ), $this->mOldUser );
 246                 $contribs = $sk->makeKnownLinkObj( Title::makeTitle( NS_SPECIAL, 'Contributions' ), wfMsg( 'contribslink' ),
 247                         'target=' . urlencode($this->mOldUser) );
 248                 $nextlink = $sk->makeKnownLinkObj( $wgTitle, wfMsgHtml( 'nextdiff' ), 'diff=next&oldid='.$this->mNewid, '', '', 'id="differences-nextlink"' );
 249                 $header = "<div class=\"firstrevisionheader\" style=\"text-align: center\"><strong>{$this->mOldtitle}</strong><br />$userLink " .
 250                         "($uTLink | $contribs)<br />" . $this->mOldComment .
 251                         '<br />' . $nextlink. "</div>\n";
 252
 253                 $wgOut->addHTML( $header );
 254
 255                 $wgOut->setSubtitle( wfMsg( 'difference' ) );
 256                 $wgOut->setRobotpolicy( 'noindex,follow' );
 257
 258
 259                 # Show current revision
 260                 #
 261                 $wgOut->addHTML( "<hr /><h2>{$this->mPagetitle}</h2>\n" );
 262                 $wgOut->addWikiText( $this->mNewtext );
 263
 264                 wfProfileOut( $fname );
 265         }
 266
 267         function showDiff( $otext, $ntext, $otitle, $ntitle ) {
 268                 global $wgOut;
 269                 $wgOut->addHTML( DifferenceEngine::getDiff( $otext, $ntext, $otitle, $ntitle ) );
 270         }
 271
 272         function getDiff( $otext, $ntext, $otitle, $ntitle ) {
 273                 global $wgUseExternalDiffEngine, $wgContLang;
 274                 $out = "
 275                         <table border='0' width='98%' cellpadding='0' cellspacing='4' class='diff'>
 276                         <tr>
 277                                 <td colspan='2' width='50%' align='center' class='diff-otitle'>{$otitle}</td>
 278                                 <td colspan='2' width='50%' align='center' class='diff-ntitle'>{$ntitle}</td>
 279                         </tr>
 280                 ";
 281                 $otext = $wgContLang->segmentForDiff($otext);
 282                 $ntext = $wgContLang->segmentForDiff($ntext);
 283                 $difftext='';
 284                 if ( $wgUseExternalDiffEngine ) {
 285                         # For historical reasons, external diff engine expects
 286                         # input text to be HTML-escaped already
 287                         $otext = str_replace( "\r\n", "\n", htmlspecialchars ( $otext ) );
 288                         $ntext = str_replace( "\r\n", "\n", htmlspecialchars ( $ntext ) );
 289                         if( !function_exists( 'wikidiff_do_diff' ) ) {
 290                                 dl('php_wikidiff.so');
 291                         }
 292                         $difftext = wikidiff_do_diff( $otext, $ntext, 2 );
 293                 } else {
 294                         $ota = explode( "\n", str_replace( "\r\n", "\n", $otext ) );
 295                         $nta = explode( "\n", str_replace( "\r\n", "\n", $ntext ) );
 296                         $diffs =& new Diff( $ota, $nta );
 297                         $formatter =& new TableDiffFormatter();
 298                         $difftext = $formatter->format( $diffs );
 299                 }
 300                 $difftext = $wgContLang->unsegmentForDiff($difftext);
 301                 $out .= $difftext."</table>\n";
 302                 return $out;
 303         }
 304
 305         /**
 306          * Load the text of the articles to compare.  If newid is 0, then compare
 307          * the old article in oldid to the current article; if oldid is 0, then
 308          * compare the current article to the immediately previous one (ignoring the
 309          * value of newid).
 310          */
 311         function loadText() {
 312                 global $wgTitle, $wgOut, $wgLang;
 313                 $fname = 'DifferenceEngine::loadText';
 314
 315                 $dbr =& wfGetDB( DB_SLAVE );
 316                 if( $this->mNewid ) {
 317                         $this->newRev = Revision::newFromId( $this->mNewid );
 318                 } else {
 319                         $this->newRev = Revision::newFromTitle( $wgTitle );
 320                 }
 321                 if( is_null( $this->newRev ) ) {
 322                         return false;
 323                 }
 324
 325                 if( $this->newRev->isCurrent() ) {
 326                         $wgOut->setArticleFlag( true );
 327                         $this->mPagetitle = htmlspecialchars( wfMsg( 'currentrev' ) );
 328                         $this->mNewPage = $wgTitle;
 329                         $newLink = $this->mNewPage->escapeLocalUrl();
 330                         $this->mNewtitle = "<a href='$newLink'>{$this->mPagetitle}</a>";
 331                 } else {
 332                         $this->mNewPage = $this->newRev->getTitle();
 333                         $newLink = $this->mNewPage->escapeLocalUrl ('oldid=' . $this->mNewid );
 334                         $t = $wgLang->timeanddate( $this->newRev->getTimestamp(), true );
 335                         $this->mPagetitle = htmlspecialchars( wfMsg( 'revisionasof', $t ) );
 336                         $this->mNewtitle = "<a href='$newLink'>{$this->mPagetitle}</a>";
 337                 }
 338
 339                 if( $this->mOldid ) {
 340                         $this->oldRev = Revision::newFromId( $this->mOldid );
 341                 } else {
 342                         $this->oldRev = $this->newRev->getPrevious();
 343                         $this->mOldid = $this->oldRev->getId();
 344                 }
 345                 if( is_null( $this->oldRev ) ) {
 346                         return false;
 347                 }
 348
 349                 $this->mOldPage = $this->oldRev->getTitle();
 350
 351                 $t = $wgLang->timeanddate( $this->oldRev->getTimestamp(), true );
 352                 $oldLink = $this->mOldPage->escapeLocalUrl( 'oldid=' . $this->mOldid );
 353                 $this->mOldtitle = "<a href='$oldLink'>" . htmlspecialchars( wfMsg( 'revisionasof', $t ) ) . '</a>';
 354
 355                 $this->mNewUser = $this->newRev->getUserText();
 356                 $this->mNewComment = $this->newRev->getComment();
 357                 $this->mNewtext = $this->newRev->getText();
 358
 359                 $this->mOldUser = $this->oldRev->getUserText();
 360                 $this->mOldComment = $this->oldRev->getComment();
 361                 $this->mOldtext = $this->oldRev->getText();
 362
 363                 return true;
 364         }
 365 }
 366
 367 // A PHP diff engine for phpwiki. (Taken from phpwiki-1.3.3)
 368 //
 369 // Copyright (C) 2000, 2001 Geoffrey T. Dairiki <dairiki@dairiki.org>
 370 // You may copy this code freely under the conditions of the GPL.
 371 //
 372
 373 define('USE_ASSERTS', function_exists('assert'));
 374
 375 /**
 376  * @todo document
 377  * @access private
 378  * @package MediaWiki
 379  * @subpackage DifferenceEngine
 380  */
 381 class _DiffOp {
 382         var $type;
 383         var $orig;
 384         var $closing;
 385
 386         function reverse() {
 387                 trigger_error('pure virtual', E_USER_ERROR);
 388         }
 389
 390         function norig() {
 391                 return $this->orig ? sizeof($this->orig) : 0;
 392         }
 393
 394         function nclosing() {
 395                 return $this->closing ? sizeof($this->closing) : 0;
 396         }
 397 }
 398
 399 /**
 400  * @todo document
 401  * @access private
 402  * @package MediaWiki
 403  * @subpackage DifferenceEngine
 404  */
 405 class _DiffOp_Copy extends _DiffOp {
 406         var $type = 'copy';
 407
 408         function _DiffOp_Copy ($orig, $closing = false) {
 409                 if (!is_array($closing))
 410                         $closing = $orig;
 411                 $this->orig = $orig;
 412                 $this->closing = $closing;
 413         }
 414
 415         function reverse() {
 416                 return new _DiffOp_Copy($this->closing, $this->orig);
 417         }
 418 }
 419
 420 /**
 421  * @todo document
 422  * @access private
 423  * @package MediaWiki
 424  * @subpackage DifferenceEngine
 425  */
 426 class _DiffOp_Delete extends _DiffOp {
 427         var $type = 'delete';
 428
 429         function _DiffOp_Delete ($lines) {
 430                 $this->orig = $lines;
 431                 $this->closing = false;
 432         }
 433
 434         function reverse() {
 435                 return new _DiffOp_Add($this->orig);
 436         }
 437 }
 438
 439 /**
 440  * @todo document
 441  * @access private
 442  * @package MediaWiki
 443  * @subpackage DifferenceEngine
 444  */
 445 class _DiffOp_Add extends _DiffOp {
 446         var $type = 'add';
 447
 448         function _DiffOp_Add ($lines) {
 449                 $this->closing = $lines;
 450                 $this->orig = false;
 451         }
 452
 453         function reverse() {
 454                 return new _DiffOp_Delete($this->closing);
 455         }
 456 }
 457
 458 /**
 459  * @todo document
 460  * @access private
 461  * @package MediaWiki
 462  * @subpackage DifferenceEngine
 463  */
 464 class _DiffOp_Change extends _DiffOp {
 465         var $type = 'change';
 466
 467         function _DiffOp_Change ($orig, $closing) {
 468                 $this->orig = $orig;
 469                 $this->closing = $closing;
 470         }
 471
 472         function reverse() {
 473                 return new _DiffOp_Change($this->closing, $this->orig);
 474         }
 475 }
 476
 477
 478 /**
 479  * Class used internally by Diff to actually compute the diffs.
 480  *
 481  * The algorithm used here is mostly lifted from the perl module
 482  * Algorithm::Diff (version 1.06) by Ned Konz, which is available at:
 483  *       http://www.perl.com/CPAN/authors/id/N/NE/NEDKONZ/Algorithm-Diff-1.06.zip
 484  *
 485  * More ideas are taken from:
 486  *       http://www.ics.uci.edu/~eppstein/161/960229.html
 487  *
 488  * Some ideas are (and a bit of code) are from from analyze.c, from GNU
 489  * diffutils-2.7, which can be found at:
 490  *       ftp://gnudist.gnu.org/pub/gnu/diffutils/diffutils-2.7.tar.gz
 491  *
 492  * closingly, some ideas (subdivision by NCHUNKS > 2, and some optimizations)
 493  * are my own.
 494  *
 495  * Line length limits for robustness added by Tim Starling, 2005-08-31
 496  *
 497  * @author Geoffrey T. Dairiki, Tim Starling
 498  * @access private
 499  * @package MediaWiki
 500  * @subpackage DifferenceEngine
 501  */
 502 class _DiffEngine
 503 {
 504         function diff ($from_lines, $to_lines) {
 505                 $fname = '_DiffEngine::diff';
 506                 wfProfileIn( $fname );
 507
 508                 $n_from = sizeof($from_lines);
 509                 $n_to = sizeof($to_lines);
 510
 511                 $this->xchanged = $this->ychanged = array();
 512                 $this->xv = $this->yv = array();
 513                 $this->xind = $this->yind = array();
 514                 unset($this->seq);
 515                 unset($this->in_seq);
 516                 unset($this->lcs);
 517
 518                 // Skip leading common lines.
 519                 for ($skip = 0; $skip < $n_from && $skip < $n_to; $skip++) {
 520                         if ($from_lines[$skip] != $to_lines[$skip])
 521                                 break;
 522                         $this->xchanged[$skip] = $this->ychanged[$skip] = false;
 523                 }
 524                 // Skip trailing common lines.
 525                 $xi = $n_from; $yi = $n_to;
 526                 for ($endskip = 0; --$xi > $skip && --$yi > $skip; $endskip++) {
 527                         if ($from_lines[$xi] != $to_lines[$yi])
 528                                 break;
 529                         $this->xchanged[$xi] = $this->ychanged[$yi] = false;
 530                 }
 531
 532                 // Ignore lines which do not exist in both files.
 533                 for ($xi = $skip; $xi < $n_from - $endskip; $xi++) {
 534                         $xhash[$this->_line_hash($from_lines[$xi])] = 1;
 535                 }
 536
 537                 for ($yi = $skip; $yi < $n_to - $endskip; $yi++) {
 538                         $line = $to_lines[$yi];
 539                         if ( ($this->ychanged[$yi] = empty($xhash[$this->_line_hash($line)])) )
 540                                 continue;
 541                         $yhash[$this->_line_hash($line)] = 1;
 542                         $this->yv[] = $line;
 543                         $this->yind[] = $yi;
 544                 }
 545                 for ($xi = $skip; $xi < $n_from - $endskip; $xi++) {
 546                         $line = $from_lines[$xi];
 547                         if ( ($this->xchanged[$xi] = empty($yhash[$this->_line_hash($line)])) )
 548                                 continue;
 549                         $this->xv[] = $line;
 550                         $this->xind[] = $xi;
 551                 }
 552
 553                 // Find the LCS.
 554                 $this->_compareseq(0, sizeof($this->xv), 0, sizeof($this->yv));
 555
 556                 // Merge edits when possible
 557                 $this->_shift_boundaries($from_lines, $this->xchanged, $this->ychanged);
 558                 $this->_shift_boundaries($to_lines, $this->ychanged, $this->xchanged);
 559
 560                 // Compute the edit operations.
 561                 $edits = array();
 562                 $xi = $yi = 0;
 563                 while ($xi < $n_from || $yi < $n_to) {
 564                         USE_ASSERTS && assert($yi < $n_to || $this->xchanged[$xi]);
 565                         USE_ASSERTS && assert($xi < $n_from || $this->ychanged[$yi]);
 566
 567                         // Skip matching "snake".
 568                         $copy = array();
 569                         while ( $xi < $n_from && $yi < $n_to
 570                                         && !$this->xchanged[$xi] && !$this->ychanged[$yi]) {
 571                                 $copy[] = $from_lines[$xi++];
 572                                 ++$yi;
 573                         }
 574                         if ($copy)
 575                                 $edits[] = new _DiffOp_Copy($copy);
 576
 577                         // Find deletes & adds.
 578                         $delete = array();
 579                         while ($xi < $n_from && $this->xchanged[$xi])
 580                                 $delete[] = $from_lines[$xi++];
 581
 582                         $add = array();
 583                         while ($yi < $n_to && $this->ychanged[$yi])
 584                                 $add[] = $to_lines[$yi++];
 585
 586                         if ($delete && $add)
 587                                 $edits[] = new _DiffOp_Change($delete, $add);
 588                         elseif ($delete)
 589                                 $edits[] = new _DiffOp_Delete($delete);
 590                         elseif ($add)
 591                                 $edits[] = new _DiffOp_Add($add);
 592                 }
 593                 wfProfileOut( $fname );
 594                 return $edits;
 595         }
 596
 597         /**
 598          * Returns the whole line if it's small enough, or the MD5 hash otherwise
 599          */
 600         function _line_hash( $line ) {
 601                 if ( strlen( $line ) > MAX_DIFF_XREF_LENGTH ) {
 602                         return md5( $line );
 603                 } else {
 604                         return $line;
 605                 }
 606         }
 607
 608
 609         /* Divide the Largest Common Subsequence (LCS) of the sequences
 610          * [XOFF, XLIM) and [YOFF, YLIM) into NCHUNKS approximately equally
 611          * sized segments.
 612          *
 613          * Returns (LCS, PTS).  LCS is the length of the LCS. PTS is an
 614          * array of NCHUNKS+1 (X, Y) indexes giving the diving points between
 615          * sub sequences.  The first sub-sequence is contained in [X0, X1),
 616          * [Y0, Y1), the second in [X1, X2), [Y1, Y2) and so on.  Note
 617          * that (X0, Y0) == (XOFF, YOFF) and
 618          * (X[NCHUNKS], Y[NCHUNKS]) == (XLIM, YLIM).
 619          *
 620          * This function assumes that the first lines of the specified portions
 621          * of the two files do not match, and likewise that the last lines do not
 622          * match.  The caller must trim matching lines from the beginning and end
 623          * of the portions it is going to specify.
 624          */
 625         function _diag ($xoff, $xlim, $yoff, $ylim, $nchunks) {
 626                 $fname = '_DiffEngine::_diag';
 627                 wfProfileIn( $fname );
 628                 $flip = false;
 629
 630                 if ($xlim - $xoff > $ylim - $yoff) {
 631                         // Things seems faster (I'm not sure I understand why)
 632                                 // when the shortest sequence in X.
 633                                 $flip = true;
 634                         list ($xoff, $xlim, $yoff, $ylim)
 635                         = array( $yoff, $ylim, $xoff, $xlim);
 636                 }
 637
 638                 if ($flip)
 639                         for ($i = $ylim - 1; $i >= $yoff; $i--)
 640                                 $ymatches[$this->xv[$i]][] = $i;
 641                 else
 642                         for ($i = $ylim - 1; $i >= $yoff; $i--)
 643                                 $ymatches[$this->yv[$i]][] = $i;
 644
 645                 $this->lcs = 0;
 646                 $this->seq[0]= $yoff - 1;
 647                 $this->in_seq = array();
 648                 $ymids[0] = array();
 649
 650                 $numer = $xlim - $xoff + $nchunks - 1;
 651                 $x = $xoff;
 652                 for ($chunk = 0; $chunk < $nchunks; $chunk++) {
 653                         wfProfileIn( "$fname-chunk" );
 654                         if ($chunk > 0)
 655                                 for ($i = 0; $i <= $this->lcs; $i++)
 656                                         $ymids[$i][$chunk-1] = $this->seq[$i];
 657
 658                         $x1 = $xoff + (int)(($numer + ($xlim-$xoff)*$chunk) / $nchunks);
 659                         for ( ; $x < $x1; $x++) {
 660                                 $line = $flip ? $this->yv[$x] : $this->xv[$x];
 661                                         if (empty($ymatches[$line]))
 662                                                 continue;
 663                                 $matches = $ymatches[$line];
 664                                 reset($matches);
 665                                 while (list ($junk, $y) = each($matches))
 666                                         if (empty($this->in_seq[$y])) {
 667                                                 $k = $this->_lcs_pos($y);
 668                                                 USE_ASSERTS && assert($k > 0);
 669                                                 $ymids[$k] = $ymids[$k-1];
 670                                                 break;
 671                                         }
 672                                 while (list ($junk, $y) = each($matches)) {
 673                                         if ($y > $this->seq[$k-1]) {
 674                                                 USE_ASSERTS && assert($y < $this->seq[$k]);
 675                                                 // Optimization: this is a common case:
 676                                                 //      next match is just replacing previous match.
 677                                                 $this->in_seq[$this->seq[$k]] = false;
 678                                                 $this->seq[$k] = $y;
 679                                                 $this->in_seq[$y] = 1;
 680                                         } else if (empty($this->in_seq[$y])) {
 681                                                 $k = $this->_lcs_pos($y);
 682                                                 USE_ASSERTS && assert($k > 0);
 683                                                 $ymids[$k] = $ymids[$k-1];
 684                                         }
 685                                 }
 686                         }
 687                         wfProfileOut( "$fname-chunk" );
 688                 }
 689
 690                 $seps[] = $flip ? array($yoff, $xoff) : array($xoff, $yoff);
 691                 $ymid = $ymids[$this->lcs];
 692                 for ($n = 0; $n < $nchunks - 1; $n++) {
 693                         $x1 = $xoff + (int)(($numer + ($xlim - $xoff) * $n) / $nchunks);
 694                         $y1 = $ymid[$n] + 1;
 695                         $seps[] = $flip ? array($y1, $x1) : array($x1, $y1);
 696                 }
 697                 $seps[] = $flip ? array($ylim, $xlim) : array($xlim, $ylim);
 698
 699                 wfProfileOut( $fname );
 700                 return array($this->lcs, $seps);
 701         }
 702
 703         function _lcs_pos ($ypos) {
 704                 $fname = '_DiffEngine::_lcs_pos';
 705                 wfProfileIn( $fname );
 706
 707                 $end = $this->lcs;
 708                 if ($end == 0 || $ypos > $this->seq[$end]) {
 709                         $this->seq[++$this->lcs] = $ypos;
 710                         $this->in_seq[$ypos] = 1;
 711                         wfProfileOut( $fname );
 712                         return $this->lcs;
 713                 }
 714
 715                 $beg = 1;
 716                 while ($beg < $end) {
 717                         $mid = (int)(($beg + $end) / 2);
 718                         if ( $ypos > $this->seq[$mid] )
 719                                 $beg = $mid + 1;
 720                         else
 721                                 $end = $mid;
 722                 }
 723
 724                 USE_ASSERTS && assert($ypos != $this->seq[$end]);
 725
 726                 $this->in_seq[$this->seq[$end]] = false;
 727                 $this->seq[$end] = $ypos;
 728                 $this->in_seq[$ypos] = 1;
 729                 wfProfileOut( $fname );
 730                 return $end;
 731         }
 732
 733         /* Find LCS of two sequences.
 734          *
 735          * The results are recorded in the vectors $this->{x,y}changed[], by
 736          * storing a 1 in the element for each line that is an insertion
 737          * or deletion (ie. is not in the LCS).
 738          *
 739          * The subsequence of file 0 is [XOFF, XLIM) and likewise for file 1.
 740          *
 741          * Note that XLIM, YLIM are exclusive bounds.
 742          * All line numbers are origin-0 and discarded lines are not counted.
 743          */
 744         function _compareseq ($xoff, $xlim, $yoff, $ylim) {
 745                 $fname = '_DiffEngine::_compareseq';
 746                 wfProfileIn( $fname );
 747
 748                 // Slide down the bottom initial diagonal.
 749                 while ($xoff < $xlim && $yoff < $ylim
 750                            && $this->xv[$xoff] == $this->yv[$yoff]) {
 751                         ++$xoff;
 752                         ++$yoff;
 753                 }
 754
 755                 // Slide up the top initial diagonal.
 756                 while ($xlim > $xoff && $ylim > $yoff
 757                            && $this->xv[$xlim - 1] == $this->yv[$ylim - 1]) {
 758                         --$xlim;
 759                         --$ylim;
 760                 }
 761
 762                 if ($xoff == $xlim || $yoff == $ylim)
 763                         $lcs = 0;
 764                 else {
 765                         // This is ad hoc but seems to work well.
 766                         //$nchunks = sqrt(min($xlim - $xoff, $ylim - $yoff) / 2.5);
 767                         //$nchunks = max(2,min(8,(int)$nchunks));
 768                         $nchunks = min(7, $xlim - $xoff, $ylim - $yoff) + 1;
 769                         list ($lcs, $seps)
 770                         = $this->_diag($xoff,$xlim,$yoff, $ylim,$nchunks);
 771                 }
 772
 773                 if ($lcs == 0) {
 774                         // X and Y sequences have no common subsequence:
 775                         // mark all changed.
 776                         while ($yoff < $ylim)
 777                                 $this->ychanged[$this->yind[$yoff++]] = 1;
 778                         while ($xoff < $xlim)
 779                                 $this->xchanged[$this->xind[$xoff++]] = 1;
 780                 } else {
 781                         // Use the partitions to split this problem into subproblems.
 782                         reset($seps);
 783                         $pt1 = $seps[0];
 784                         while ($pt2 = next($seps)) {
 785                                 $this->_compareseq ($pt1[0], $pt2[0], $pt1[1], $pt2[1]);
 786                                 $pt1 = $pt2;
 787                         }
 788                 }
 789                 wfProfileOut( $fname );
 790         }
 791
 792         /* Adjust inserts/deletes of identical lines to join changes
 793          * as much as possible.
 794          *
 795          * We do something when a run of changed lines include a
 796          * line at one end and has an excluded, identical line at the other.
 797          * We are free to choose which identical line is included.
 798          * `compareseq' usually chooses the one at the beginning,
 799          * but usually it is cleaner to consider the following identical line
 800          * to be the "change".
 801          *
 802          * This is extracted verbatim from analyze.c (GNU diffutils-2.7).
 803          */
 804         function _shift_boundaries ($lines, &$changed, $other_changed) {
 805                 $fname = '_DiffEngine::_shift_boundaries';
 806                 wfProfileIn( $fname );
 807                 $i = 0;
 808                 $j = 0;
 809
 810                 USE_ASSERTS && assert('sizeof($lines) == sizeof($changed)');
 811                 $len = sizeof($lines);
 812                 $other_len = sizeof($other_changed);
 813
 814                 while (1) {
 815                         /*
 816                          * Scan forwards to find beginning of another run of changes.
 817                          * Also keep track of the corresponding point in the other file.
 818                          *
 819                          * Throughout this code, $i and $j are adjusted together so that
 820                          * the first $i elements of $changed and the first $j elements
 821                          * of $other_changed both contain the same number of zeros
 822                          * (unchanged lines).
 823                          * Furthermore, $j is always kept so that $j == $other_len or
 824                          * $other_changed[$j] == false.
 825                          */
 826                         while ($j < $other_len && $other_changed[$j])
 827                                 $j++;
 828
 829                         while ($i < $len && ! $changed[$i]) {
 830                                 USE_ASSERTS && assert('$j < $other_len && ! $other_changed[$j]');
 831                                 $i++; $j++;
 832                                 while ($j < $other_len && $other_changed[$j])
 833                                         $j++;
 834                         }
 835
 836                         if ($i == $len)
 837                                 break;
 838
 839                         $start = $i;
 840
 841                         // Find the end of this run of changes.
 842                         while (++$i < $len && $changed[$i])
 843                                 continue;
 844
 845                         do {
 846                                 /*
 847                                  * Record the length of this run of changes, so that
 848                                  * we can later determine whether the run has grown.
 849                                  */
 850                                 $runlength = $i - $start;
 851
 852                                 /*
 853                                  * Move the changed region back, so long as the
 854                                  * previous unchanged line matches the last changed one.
 855                                  * This merges with previous changed regions.
 856                                  */
 857                                 while ($start > 0 && $lines[$start - 1] == $lines[$i - 1]) {
 858                                         $changed[--$start] = 1;
 859                                         $changed[--$i] = false;
 860                                         while ($start > 0 && $changed[$start - 1])
 861                                                 $start--;
 862                                         USE_ASSERTS && assert('$j > 0');
 863                                         while ($other_changed[--$j])
 864                                                 continue;
 865                                         USE_ASSERTS && assert('$j >= 0 && !$other_changed[$j]');
 866                                 }
 867
 868                                 /*
 869                                  * Set CORRESPONDING to the end of the changed run, at the last
 870                                  * point where it corresponds to a changed run in the other file.
 871                                  * CORRESPONDING == LEN means no such point has been found.
 872                                  */
 873                                 $corresponding = $j < $other_len ? $i : $len;
 874
 875                                 /*
 876                                  * Move the changed region forward, so long as the
 877                                  * first changed line matches the following unchanged one.
 878                                  * This merges with following changed regions.
 879                                  * Do this second, so that if there are no merges,
 880                                  * the changed region is moved forward as far as possible.
 881                                  */
 882                                 while ($i < $len && $lines[$start] == $lines[$i]) {
 883                                         $changed[$start++] = false;
 884                                         $changed[$i++] = 1;
 885                                         while ($i < $len && $changed[$i])
 886                                                 $i++;
 887
 888                                         USE_ASSERTS && assert('$j < $other_len && ! $other_changed[$j]');
 889                                         $j++;
 890                                         if ($j < $other_len && $other_changed[$j]) {
 891                                                 $corresponding = $i;
 892                                                 while ($j < $other_len && $other_changed[$j])
 893                                                         $j++;
 894                                         }
 895                                 }
 896                         } while ($runlength != $i - $start);
 897
 898                         /*
 899                          * If possible, move the fully-merged run of changes
 900                          * back to a corresponding run in the other file.
 901                          */
 902                         while ($corresponding < $i) {
 903                                 $changed[--$start] = 1;
 904                                 $changed[--$i] = 0;
 905                                 USE_ASSERTS && assert('$j > 0');
 906                                 while ($other_changed[--$j])
 907                                         continue;
 908                                 USE_ASSERTS && assert('$j >= 0 && !$other_changed[$j]');
 909                         }
 910                 }
 911                 wfProfileOut( $fname );
 912         }
 913 }
 914
 915 /**
 916  * Class representing a 'diff' between two sequences of strings.
 917  * @todo document
 918  * @access private
 919  * @package MediaWiki
 920  * @subpackage DifferenceEngine
 921  */
 922 class Diff
 923 {
 924         var $edits;
 925
 926         /**
 927          * Constructor.
 928          * Computes diff between sequences of strings.
 929          *
 930          * @param $from_lines array An array of strings.
 931          *                (Typically these are lines from a file.)
 932          * @param $to_lines array An array of strings.
 933          */
 934         function Diff($from_lines, $to_lines) {
 935                 $eng = new _DiffEngine;
 936                 $this->edits = $eng->diff($from_lines, $to_lines);
 937                 //$this->_check($from_lines, $to_lines);
 938         }
 939
 940         /**
 941          * Compute reversed Diff.
 942          *
 943          * SYNOPSIS:
 944          *
 945          *      $diff = new Diff($lines1, $lines2);
 946          *      $rev = $diff->reverse();
 947          * @return object A Diff object representing the inverse of the
 948          *                                original diff.
 949          */
 950         function reverse () {
 951                 $rev = $this;
 952                 $rev->edits = array();
 953                 foreach ($this->edits as $edit) {
 954                         $rev->edits[] = $edit->reverse();
 955                 }
 956                 return $rev;
 957         }
 958
 959         /**
 960          * Check for empty diff.
 961          *
 962          * @return bool True iff two sequences were identical.
 963          */
 964         function isEmpty () {
 965                 foreach ($this->edits as $edit) {
 966                         if ($edit->type != 'copy')
 967                                 return false;
 968                 }
 969                 return true;
 970         }
 971
 972         /**
 973          * Compute the length of the Longest Common Subsequence (LCS).
 974          *
 975          * This is mostly for diagnostic purposed.
 976          *
 977          * @return int The length of the LCS.
 978          */
 979         function lcs () {
 980                 $lcs = 0;
 981                 foreach ($this->edits as $edit) {
 982                         if ($edit->type == 'copy')
 983                                 $lcs += sizeof($edit->orig);
 984                 }
 985                 return $lcs;
 986         }
 987
 988         /**
 989          * Get the original set of lines.
 990          *
 991          * This reconstructs the $from_lines parameter passed to the
 992          * constructor.
 993          *
 994          * @return array The original sequence of strings.
 995          */
 996         function orig() {
 997                 $lines = array();
 998
 999                 foreach ($this->edits as $edit) {
1000                         if ($edit->orig)
1001                                 array_splice($lines, sizeof($lines), 0, $edit->orig);
1002                 }
1003                 return $lines;
1004         }
1005
1006         /**
1007          * Get the closing set of lines.
1008          *
1009          * This reconstructs the $to_lines parameter passed to the
1010          * constructor.
1011          *
1012          * @return array The sequence of strings.
1013          */
1014         function closing() {
1015                 $lines = array();
1016
1017                 foreach ($this->edits as $edit) {
1018                         if ($edit->closing)
1019                                 array_splice($lines, sizeof($lines), 0, $edit->closing);
1020                 }
1021                 return $lines;
1022         }
1023
1024         /**
1025          * Check a Diff for validity.
1026          *
1027          * This is here only for debugging purposes.
1028          */
1029         function _check ($from_lines, $to_lines) {
1030                 $fname = 'Diff::_check';
1031                 wfProfileIn( $fname );
1032                 if (serialize($from_lines) != serialize($this->orig()))
1033                         trigger_error("Reconstructed original doesn't match", E_USER_ERROR);
1034                 if (serialize($to_lines) != serialize($this->closing()))
1035                         trigger_error("Reconstructed closing doesn't match", E_USER_ERROR);
1036
1037                 $rev = $this->reverse();
1038                 if (serialize($to_lines) != serialize($rev->orig()))
1039                         trigger_error("Reversed original doesn't match", E_USER_ERROR);
1040                 if (serialize($from_lines) != serialize($rev->closing()))
1041                         trigger_error("Reversed closing doesn't match", E_USER_ERROR);
1042
1043
1044                 $prevtype = 'none';
1045                 foreach ($this->edits as $edit) {
1046                         if ( $prevtype == $edit->type )
1047                                 trigger_error("Edit sequence is non-optimal", E_USER_ERROR);
1048                         $prevtype = $edit->type;
1049                 }
1050
1051                 $lcs = $this->lcs();
1052                 trigger_error('Diff okay: LCS = '.$lcs, E_USER_NOTICE);
1053                 wfProfileOut( $fname );
1054         }
1055 }
1056
1057 /**
1058  * FIXME: bad name.
1059  * @todo document
1060  * @access private
1061  * @package MediaWiki
1062  * @subpackage DifferenceEngine
1063  */
1064 class MappedDiff extends Diff
1065 {
1066         /**
1067          * Constructor.
1068          *
1069          * Computes diff between sequences of strings.
1070          *
1071          * This can be used to compute things like
1072          * case-insensitve diffs, or diffs which ignore
1073          * changes in white-space.
1074          *
1075          * @param $from_lines array An array of strings.
1076          *      (Typically these are lines from a file.)
1077          *
1078          * @param $to_lines array An array of strings.
1079          *
1080          * @param $mapped_from_lines array This array should
1081          *      have the same size number of elements as $from_lines.
1082          *      The elements in $mapped_from_lines and
1083          *      $mapped_to_lines are what is actually compared
1084          *      when computing the diff.
1085          *
1086          * @param $mapped_to_lines array This array should
1087          *      have the same number of elements as $to_lines.
1088          */
1089         function MappedDiff($from_lines, $to_lines,
1090                                                 $mapped_from_lines, $mapped_to_lines) {
1091                 $fname = 'MappedDiff::MappedDiff';
1092                 wfProfileIn( $fname );
1093
1094                 assert(sizeof($from_lines) == sizeof($mapped_from_lines));
1095                 assert(sizeof($to_lines) == sizeof($mapped_to_lines));
1096
1097                 $this->Diff($mapped_from_lines, $mapped_to_lines);
1098
1099                 $xi = $yi = 0;
1100                 for ($i = 0; $i < sizeof($this->edits); $i++) {
1101                         $orig = &$this->edits[$i]->orig;
1102                         if (is_array($orig)) {
1103                                 $orig = array_slice($from_lines, $xi, sizeof($orig));
1104                                 $xi += sizeof($orig);
1105                         }
1106
1107                         $closing = &$this->edits[$i]->closing;
1108                         if (is_array($closing)) {
1109                                 $closing = array_slice($to_lines, $yi, sizeof($closing));
1110                                 $yi += sizeof($closing);
1111                         }
1112                 }
1113                 wfProfileOut( $fname );
1114         }
1115 }
1116
1117 /**
1118  * A class to format Diffs
1119  *
1120  * This class formats the diff in classic diff format.
1121  * It is intended that this class be customized via inheritance,
1122  * to obtain fancier outputs.
1123  * @todo document
1124  * @access private
1125  * @package MediaWiki
1126  * @subpackage DifferenceEngine
1127  */
1128 class DiffFormatter
1129 {
1130         /**
1131          * Number of leading context "lines" to preserve.
1132          *
1133          * This should be left at zero for this class, but subclasses
1134          * may want to set this to other values.
1135          */
1136         var $leading_context_lines = 0;
1137
1138         /**
1139          * Number of trailing context "lines" to preserve.
1140          *
1141          * This should be left at zero for this class, but subclasses
1142          * may want to set this to other values.
1143          */
1144         var $trailing_context_lines = 0;
1145
1146         /**
1147          * Format a diff.
1148          *
1149          * @param $diff object A Diff object.
1150          * @return string The formatted output.
1151          */
1152         function format($diff) {
1153                 $fname = 'DiffFormatter::format';
1154                 wfProfileIn( $fname );
1155
1156                 $xi = $yi = 1;
1157                 $block = false;
1158                 $context = array();
1159
1160                 $nlead = $this->leading_context_lines;
1161                 $ntrail = $this->trailing_context_lines;
1162
1163                 $this->_start_diff();
1164
1165                 foreach ($diff->edits as $edit) {
1166                         if ($edit->type == 'copy') {
1167                                 if (is_array($block)) {
1168                                         if (sizeof($edit->orig) <= $nlead + $ntrail) {
1169                                                 $block[] = $edit;
1170                                         }
1171                                         else{
1172                                                 if ($ntrail) {
1173                                                         $context = array_slice($edit->orig, 0, $ntrail);
1174                                                         $block[] = new _DiffOp_Copy($context);
1175                                                 }
1176                                                 $this->_block($x0, $ntrail + $xi - $x0,
1177                                                                           $y0, $ntrail + $yi - $y0,
1178                                                                           $block);
1179                                                 $block = false;
1180                                         }
1181                                 }
1182                                 $context = $edit->orig;
1183                         }
1184                         else {
1185                                 if (! is_array($block)) {
1186                                         $context = array_slice($context, sizeof($context) - $nlead);
1187                                         $x0 = $xi - sizeof($context);
1188                                         $y0 = $yi - sizeof($context);
1189                                         $block = array();
1190                                         if ($context)
1191                                                 $block[] = new _DiffOp_Copy($context);
1192                                 }
1193                                 $block[] = $edit;
1194                         }
1195
1196                         if ($edit->orig)
1197                                 $xi += sizeof($edit->orig);
1198                         if ($edit->closing)
1199                                 $yi += sizeof($edit->closing);
1200                 }
1201
1202                 if (is_array($block))
1203                         $this->_block($x0, $xi - $x0,
1204                                                   $y0, $yi - $y0,
1205                                                   $block);
1206
1207                 $end = $this->_end_diff();
1208                 wfProfileOut( $fname );
1209                 return $end;
1210         }
1211
1212         function _block($xbeg, $xlen, $ybeg, $ylen, &$edits) {
1213                 $fname = 'DiffFormatter::_block';
1214                 wfProfileIn( $fname );
1215                 $this->_start_block($this->_block_header($xbeg, $xlen, $ybeg, $ylen));
1216                 foreach ($edits as $edit) {
1217                         if ($edit->type == 'copy')
1218                                 $this->_context($edit->orig);
1219                         elseif ($edit->type == 'add')
1220                                 $this->_added($edit->closing);
1221                         elseif ($edit->type == 'delete')
1222                                 $this->_deleted($edit->orig);
1223                         elseif ($edit->type == 'change')
1224                                 $this->_changed($edit->orig, $edit->closing);
1225                         else
1226                                 trigger_error('Unknown edit type', E_USER_ERROR);
1227                 }
1228                 $this->_end_block();
1229                 wfProfileOut( $fname );
1230         }
1231
1232         function _start_diff() {
1233                 ob_start();
1234         }
1235
1236         function _end_diff() {
1237                 $val = ob_get_contents();
1238                 ob_end_clean();
1239                 return $val;
1240         }
1241
1242         function _block_header($xbeg, $xlen, $ybeg, $ylen) {
1243                 if ($xlen > 1)
1244                         $xbeg .= "," . ($xbeg + $xlen - 1);
1245                 if ($ylen > 1)
1246                         $ybeg .= "," . ($ybeg + $ylen - 1);
1247
1248                 return $xbeg . ($xlen ? ($ylen ? 'c' : 'd') : 'a') . $ybeg;
1249         }
1250
1251         function _start_block($header) {
1252                 echo $header;
1253         }
1254
1255         function _end_block() {
1256         }
1257
1258         function _lines($lines, $prefix = ' ') {
1259                 foreach ($lines as $line)
1260                         echo "$prefix $line\n";
1261         }
1262
1263         function _context($lines) {
1264                 $this->_lines($lines);
1265         }
1266
1267         function _added($lines) {
1268                 $this->_lines($lines, '>');
1269         }
1270         function _deleted($lines) {
1271                 $this->_lines($lines, '<');
1272         }
1273
1274         function _changed($orig, $closing) {
1275                 $this->_deleted($orig);
1276                 echo "---\n";
1277                 $this->_added($closing);
1278         }
1279 }
1280
1281
1282 /**
1283  *      Additions by Axel Boldt follow, partly taken from diff.php, phpwiki-1.3.3
1284  *
1285  */
1286
1287 define('NBSP', '&#160;');                       // iso-8859-x non-breaking space.
1288
1289 /**
1290  * @todo document
1291  * @access private
1292  * @package MediaWiki
1293  * @subpackage DifferenceEngine
1294  */
1295 class _HWLDF_WordAccumulator {
1296         function _HWLDF_WordAccumulator () {
1297                 $this->_lines = array();
1298                 $this->_line = '';
1299                 $this->_group = '';
1300                 $this->_tag = '';
1301         }
1302
1303         function _flushGroup ($new_tag) {
1304                 if ($this->_group !== '') {
1305                         if ($this->_tag == 'mark')
1306                                 $this->_line .= '<span class="diffchange">' .
1307                                         htmlspecialchars ( $this->_group ) . '</span>';
1308                         else
1309                                 $this->_line .= htmlspecialchars ( $this->_group );
1310                 }
1311                 $this->_group = '';
1312                 $this->_tag = $new_tag;
1313         }
1314
1315         function _flushLine ($new_tag) {
1316                 $this->_flushGroup($new_tag);
1317                 if ($this->_line != '')
1318                         array_push ( $this->_lines, $this->_line );
1319                 else
1320                         # make empty lines visible by inserting an NBSP
1321                         array_push ( $this->_lines, NBSP );
1322                 $this->_line = '';
1323         }
1324
1325         function addWords ($words, $tag = '') {
1326                 if ($tag != $this->_tag)
1327                         $this->_flushGroup($tag);
1328
1329                 foreach ($words as $word) {
1330                         // new-line should only come as first char of word.
1331                         if ($word == '')
1332                                 continue;
1333                         if ($word[0] == "\n") {
1334                                 $this->_flushLine($tag);
1335                                 $word = substr($word, 1);
1336                         }
1337                         assert(!strstr($word, "\n"));
1338                         $this->_group .= $word;
1339                 }
1340         }
1341
1342         function getLines() {
1343                 $this->_flushLine('~done');
1344                 return $this->_lines;
1345         }
1346 }
1347
1348 /**
1349  * @todo document
1350  * @access private
1351  * @package MediaWiki
1352  * @subpackage DifferenceEngine
1353  */
1354 class WordLevelDiff extends MappedDiff
1355 {
1356         function WordLevelDiff ($orig_lines, $closing_lines) {
1357                 $fname = 'WordLevelDiff::WordLevelDiff';
1358                 wfProfileIn( $fname );
1359
1360                 list ($orig_words, $orig_stripped) = $this->_split($orig_lines);
1361                 list ($closing_words, $closing_stripped) = $this->_split($closing_lines);
1362
1363                 $this->MappedDiff($orig_words, $closing_words,
1364                                                   $orig_stripped, $closing_stripped);
1365                 wfProfileOut( $fname );
1366         }
1367
1368         function _split($lines) {
1369                 $fname = 'WordLevelDiff::_split';
1370                 wfProfileIn( $fname );
1371
1372                 $words = array();
1373                 $stripped = array();
1374                 $first = true;
1375                 foreach ( $lines as $line ) {
1376                         # If the line is too long, just pretend the entire line is one big word
1377                         # This prevents resource exhaustion problems
1378                         if ( $first ) {
1379                                 $first = false;
1380                         } else {
1381                                 $words[] = "\n";
1382                                 $stripped[] = "\n";
1383                         }
1384                         if ( strlen( $line ) > MAX_DIFF_LINE ) {
1385                                 $words[] = $line;
1386                                 $stripped[] = $line;
1387                         } else {
1388                                 if (preg_match_all('/ ( [^\S\n]+ | [0-9_A-Za-z\x80-\xff]+ | . ) (?: (?!< \n) [^\S\n])? /xs',
1389                                         $line, $m))
1390                                 {
1391                                         $words = array_merge( $words, $m[0] );
1392                                         $stripped = array_merge( $stripped, $m[1] );
1393                                 }
1394                         }
1395                 }
1396                 wfProfileOut( $fname );
1397                 return array($words, $stripped);
1398         }
1399
1400         function orig () {
1401                 $fname = 'WordLevelDiff::orig';
1402                 wfProfileIn( $fname );
1403                 $orig = new _HWLDF_WordAccumulator;
1404
1405                 foreach ($this->edits as $edit) {
1406                         if ($edit->type == 'copy')
1407                                 $orig->addWords($edit->orig);
1408                         elseif ($edit->orig)
1409                                 $orig->addWords($edit->orig, 'mark');
1410                 }
1411                 $lines = $orig->getLines();
1412                 wfProfileOut( $fname );
1413                 return $lines;
1414         }
1415
1416         function closing () {
1417                 $fname = 'WordLevelDiff::closing';
1418                 wfProfileIn( $fname );
1419                 $closing = new _HWLDF_WordAccumulator;
1420
1421                 foreach ($this->edits as $edit) {
1422                         if ($edit->type == 'copy')
1423                                 $closing->addWords($edit->closing);
1424                         elseif ($edit->closing)
1425                                 $closing->addWords($edit->closing, 'mark');
1426                 }
1427                 $lines = $closing->getLines();
1428                 wfProfileOut( $fname );
1429                 return $lines;
1430         }
1431 }
1432
1433 /**
1434  *      Wikipedia Table style diff formatter.
1435  * @todo document
1436  * @access private
1437  * @package MediaWiki
1438  * @subpackage DifferenceEngine
1439  */
1440 class TableDiffFormatter extends DiffFormatter
1441 {
1442         function TableDiffFormatter() {
1443                 $this->leading_context_lines = 2;
1444                 $this->trailing_context_lines = 2;
1445         }
1446
1447         function _block_header( $xbeg, $xlen, $ybeg, $ylen ) {
1448                 $l1 = wfMsg( 'lineno', $xbeg );
1449                 $l2 = wfMsg( 'lineno', $ybeg );
1450
1451                 $r = '<tr><td colspan="2" align="left"><strong>'.$l1."</strong></td>\n" .
1452                   '<td colspan="2" align="left"><strong>'.$l2."</strong></td></tr>\n";
1453                 return $r;
1454         }
1455
1456         function _start_block( $header ) {
1457                 global $wgOut;
1458                 echo $header;
1459         }
1460
1461         function _end_block() {
1462         }
1463
1464         function _lines( $lines, $prefix=' ', $color='white' ) {
1465         }
1466
1467         # HTML-escape parameter before calling this
1468         function addedLine( $line ) {
1469                 return "<td>+</td><td class='diff-addedline'>{$line}</td>";
1470         }
1471
1472         # HTML-escape parameter before calling this
1473         function deletedLine( $line ) {
1474                 return "<td>-</td><td class='diff-deletedline'>{$line}</td>";
1475         }
1476
1477         # HTML-escape parameter before calling this
1478         function contextLine( $line ) {
1479                 return "<td> </td><td class='diff-context'>{$line}</td>";
1480         }
1481
1482         function emptyLine() {
1483                 return '<td colspan="2">&nbsp;</td>';
1484         }
1485
1486         function _added( $lines ) {
1487                 foreach ($lines as $line) {
1488                         echo '<tr>' . $this->emptyLine() .
1489                                 $this->addedLine( htmlspecialchars ( $line ) ) . "</tr>\n";
1490                 }
1491         }
1492
1493         function _deleted($lines) {
1494                 foreach ($lines as $line) {
1495                         echo '<tr>' . $this->deletedLine( htmlspecialchars ( $line ) ) .
1496                           $this->emptyLine() . "</tr>\n";
1497                 }
1498         }
1499
1500         function _context( $lines ) {
1501                 foreach ($lines as $line) {
1502                         echo '<tr>' .
1503                                 $this->contextLine( htmlspecialchars ( $line ) ) .
1504                                 $this->contextLine( htmlspecialchars ( $line ) ) . "</tr>\n";
1505                 }
1506         }
1507
1508         function _changed( $orig, $closing ) {
1509                 $fname = 'TableDiffFormatter::_changed';
1510                 wfProfileIn( $fname );
1511
1512                 $diff = new WordLevelDiff( $orig, $closing );
1513                 $del = $diff->orig();
1514                 $add = $diff->closing();
1515
1516                 # Notice that WordLevelDiff returns HTML-escaped output.
1517                 # Hence, we will be calling addedLine/deletedLine without HTML-escaping.
1518
1519                 while ( $line = array_shift( $del ) ) {
1520                         $aline = array_shift( $add );
1521                         echo '<tr>' . $this->deletedLine( $line ) .
1522                                 $this->addedLine( $aline ) . "</tr>\n";
1523                 }
1524                 foreach ($add as $line) {       # If any leftovers
1525                         echo '<tr>' . $this->emptyLine() .
1526                                 $this->addedLine( $line ) . "</tr>\n";
1527                 }
1528                 wfProfileOut( $fname );
1529         }
1530 }
1531
1532 ?>