includes/diff/DifferenceEngine.php

   1 <?php
   2 /**
   3  * User interface for the difference engine.
   4  *
   5  * This program is free software; you can redistribute it and/or modify
   6  * it under the terms of the GNU General Public License as published by
   7  * the Free Software Foundation; either version 2 of the License, or
   8  * (at your option) any later version.
   9  *
  10  * This program is distributed in the hope that it will be useful,
  11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  13  * GNU General Public License for more details.
  14  *
  15  * You should have received a copy of the GNU General Public License along
  16  * with this program; if not, write to the Free Software Foundation, Inc.,
  17  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
  18  * http://www.gnu.org/copyleft/gpl.html
  19  *
  20  * @file
  21  * @ingroup DifferenceEngine
  22  */
  23
  24 /**
  25  * Constant to indicate diff cache compatibility.
  26  * Bump this when changing the diff formatting in a way that
  27  * fixes important bugs or such to force cached diff views to
  28  * clear.
  29  */
  30 define( 'MW_DIFF_VERSION', '1.11a' );
  31
  32 /**
  33  * @todo document
  34  * @ingroup DifferenceEngine
  35  */
  36 class DifferenceEngine extends ContextSource {
  37         /**#@+
  38          * @private
  39          */
  40         var $mOldid, $mNewid;
  41         /**
  42          * @var Content
  43          */
  44         var $mOldContent, $mNewContent;
  45         protected $mDiffLang;
  46
  47         /**
  48          * @var Title
  49          */
  50         var $mOldPage, $mNewPage;
  51
  52         /**
  53          * @var Revision
  54          */
  55         var $mOldRev, $mNewRev;
  56         private $mRevisionsIdsLoaded = false; // Have the revisions IDs been loaded
  57         var $mRevisionsLoaded = false; // Have the revisions been loaded
  58         var $mTextLoaded = 0; // How many text blobs have been loaded, 0, 1 or 2?
  59         var $mCacheHit = false; // Was the diff fetched from cache?
  60
  61         /**
  62          * Set this to true to add debug info to the HTML output.
  63          * Warning: this may cause RSS readers to spuriously mark articles as "new"
  64          * (bug 20601)
  65          */
  66         var $enableDebugComment = false;
  67
  68         // If true, line X is not displayed when X is 1, for example to increase
  69         // readability and conserve space with many small diffs.
  70         protected $mReducedLineNumbers = false;
  71
  72         // Link to action=markpatrolled
  73         protected $mMarkPatrolledLink = null;
  74
  75         protected $unhide = false; # show rev_deleted content if allowed
  76         /**#@-*/
  77
  78         /**
  79          * Constructor
  80          * @param $context IContextSource context to use, anything else will be ignored
  81          * @param $old Integer old ID we want to show and diff with.
  82          * @param $new String either 'prev' or 'next'.
  83          * @param $rcid Integer Deprecated, no longer used!
  84          * @param $refreshCache boolean If set, refreshes the diff cache
  85          * @param $unhide boolean If set, allow viewing deleted revs
  86          */
  87         function __construct( $context = null, $old = 0, $new = 0, $rcid = 0,
  88                 $refreshCache = false, $unhide = false )
  89         {
  90                 if ( $context instanceof IContextSource ) {
  91                         $this->setContext( $context );
  92                 }
  93
  94                 wfDebug( "DifferenceEngine old '$old' new '$new' rcid '$rcid'\n" );
  95
  96                 $this->mOldid = $old;
  97                 $this->mNewid = $new;
  98                 $this->mRefreshCache = $refreshCache;
  99                 $this->unhide = $unhide;
 100         }
 101
 102         /**
 103          * @param $value bool
 104          */
 105         function setReducedLineNumbers( $value = true ) {
 106                 $this->mReducedLineNumbers = $value;
 107         }
 108
 109         /**
 110          * @return Language
 111          */
 112         function getDiffLang() {
 113                 if ( $this->mDiffLang === null ) {
 114                         # Default language in which the diff text is written.
 115                         $this->mDiffLang = $this->getTitle()->getPageLanguage();
 116                 }
 117                 return $this->mDiffLang;
 118         }
 119
 120         /**
 121          * @return bool
 122          */
 123         function wasCacheHit() {
 124                 return $this->mCacheHit;
 125         }
 126
 127         /**
 128          * @return int
 129          */
 130         function getOldid() {
 131                 $this->loadRevisionIds();
 132                 return $this->mOldid;
 133         }
 134
 135         /**
 136          * @return Bool|int
 137          */
 138         function getNewid() {
 139                 $this->loadRevisionIds();
 140                 return $this->mNewid;
 141         }
 142
 143         /**
 144          * Look up a special:Undelete link to the given deleted revision id,
 145          * as a workaround for being unable to load deleted diffs in currently.
 146          *
 147          * @param int $id revision ID
 148          * @return mixed URL or false
 149          */
 150         function deletedLink( $id ) {
 151                 if ( $this->getUser()->isAllowed( 'deletedhistory' ) ) {
 152                         $dbr = wfGetDB( DB_SLAVE );
 153                         $row = $dbr->selectRow( 'archive', '*',
 154                                 array( 'ar_rev_id' => $id ),
 155                                 __METHOD__ );
 156                         if ( $row ) {
 157                                 $rev = Revision::newFromArchiveRow( $row );
 158                                 $title = Title::makeTitleSafe( $row->ar_namespace, $row->ar_title );
 159                                 return SpecialPage::getTitleFor( 'Undelete' )->getFullURL( array(
 160                                         'target' => $title->getPrefixedText(),
 161                                         'timestamp' => $rev->getTimestamp()
 162                                 ));
 163                         }
 164                 }
 165                 return false;
 166         }
 167
 168         /**
 169          * Build a wikitext link toward a deleted revision, if viewable.
 170          *
 171          * @param int $id revision ID
 172          * @return string wikitext fragment
 173          */
 174         function deletedIdMarker( $id ) {
 175                 $link = $this->deletedLink( $id );
 176                 if ( $link ) {
 177                         return "[$link $id]";
 178                 } else {
 179                         return $id;
 180                 }
 181         }
 182
 183         private function showMissingRevision() {
 184                 $out = $this->getOutput();
 185
 186                 $missing = array();
 187                 if ( $this->mOldRev === null ) {
 188                         $missing[] = $this->deletedIdMarker( $this->mOldid );
 189                 }
 190                 if ( $this->mNewRev === null ) {
 191                         $missing[] = $this->deletedIdMarker( $this->mNewid );
 192                 }
 193
 194                 $out->setPageTitle( $this->msg( 'errorpagetitle' ) );
 195                 $out->addWikiMsg( 'difference-missing-revision',
 196                         $this->getLanguage()->listToText( $missing ), count( $missing ) );
 197         }
 198
 199         function showDiffPage( $diffOnly = false ) {
 200                 wfProfileIn( __METHOD__ );
 201
 202                 # Allow frames except in certain special cases
 203                 $out = $this->getOutput();
 204                 $out->allowClickjacking();
 205                 $out->setRobotPolicy( 'noindex,nofollow' );
 206
 207                 if ( !$this->loadRevisionData() ) {
 208                         $this->showMissingRevision();
 209                         wfProfileOut( __METHOD__ );
 210                         return;
 211                 }
 212
 213                 $user = $this->getUser();
 214                 $permErrors = $this->mNewPage->getUserPermissionsErrors( 'read', $user );
 215                 if ( $this->mOldPage ) { # mOldPage might not be set, see below.
 216                         $permErrors = wfMergeErrorArrays( $permErrors,
 217                                 $this->mOldPage->getUserPermissionsErrors( 'read', $user ) );
 218                 }
 219                 if ( count( $permErrors ) ) {
 220                         wfProfileOut( __METHOD__ );
 221                         throw new PermissionsError( 'read', $permErrors );
 222                 }
 223
 224                 $rollback = '';
 225                 $undoLink = '';
 226
 227                 $query = array();
 228                 # Carry over 'diffonly' param via navigation links
 229                 if ( $diffOnly != $user->getBoolOption( 'diffonly' ) ) {
 230                         $query['diffonly'] = $diffOnly;
 231                 }
 232                 # Cascade unhide param in links for easy deletion browsing
 233                 if ( $this->unhide ) {
 234                         $query['unhide'] = 1;
 235                 }
 236
 237                 # Check if one of the revisions is deleted/suppressed
 238                 $deleted = $suppressed = false;
 239                 $allowed = $this->mNewRev->userCan( Revision::DELETED_TEXT, $user );
 240
 241                 $revisionTools = array();
 242
 243                 # mOldRev is false if the difference engine is called with a "vague" query for
 244                 # a diff between a version V and its previous version V' AND the version V
 245                 # is the first version of that article. In that case, V' does not exist.
 246                 if ( $this->mOldRev === false ) {
 247                         $out->setPageTitle( $this->msg( 'difference-title', $this->mNewPage->getPrefixedText() ) );
 248                         $samePage = true;
 249                         $oldHeader = '';
 250                 } else {
 251                         wfRunHooks( 'DiffViewHeader', array( $this, $this->mOldRev, $this->mNewRev ) );
 252
 253                         if ( $this->mNewPage->equals( $this->mOldPage ) ) {
 254                                 $out->setPageTitle( $this->msg( 'difference-title', $this->mNewPage->getPrefixedText() ) );
 255                                 $samePage = true;
 256                         } else {
 257                                 $out->setPageTitle( $this->msg( 'difference-title-multipage', $this->mOldPage->getPrefixedText(),
 258                                         $this->mNewPage->getPrefixedText() ) );
 259                                 $out->addSubtitle( $this->msg( 'difference-multipage' ) );
 260                                 $samePage = false;
 261                         }
 262
 263                         if ( $samePage && $this->mNewPage->quickUserCan( 'edit', $user ) ) {
 264                                 if ( $this->mNewRev->isCurrent() && $this->mNewPage->userCan( 'rollback', $user ) ) {
 265                                         $rollbackLink = Linker::generateRollback( $this->mNewRev, $this->getContext() );
 266                                         if ( $rollbackLink ) {
 267                                                 $out->preventClickjacking();
 268                                                 $rollback = '&#160;&#160;&#160;' . $rollbackLink;
 269                                         }
 270                                 }
 271                                 if ( !$this->mOldRev->isDeleted( Revision::DELETED_TEXT ) && !$this->mNewRev->isDeleted( Revision::DELETED_TEXT ) ) {
 272                                         $undoLink = Html::element( 'a', array(
 273                                                         'href' => $this->mNewPage->getLocalURL( array(
 274                                                                 'action' => 'edit',
 275                                                                 'undoafter' => $this->mOldid,
 276                                                                 'undo' => $this->mNewid ) ),
 277                                                         'title' => Linker::titleAttrib( 'undo' )
 278                                                 ),
 279                                                 $this->msg( 'editundo' )->text()
 280                                         );
 281                                         $revisionTools[] = $undoLink;
 282                                 }
 283                         }
 284
 285                         # Make "previous revision link"
 286                         if ( $samePage && $this->mOldRev->getPrevious() ) {
 287                                 $prevlink = Linker::linkKnown(
 288                                         $this->mOldPage,
 289                                         $this->msg( 'previousdiff' )->escaped(),
 290                                         array( 'id' => 'differences-prevlink' ),
 291                                         array( 'diff' => 'prev', 'oldid' => $this->mOldid ) + $query
 292                                 );
 293                         } else {
 294                                 $prevlink = '&#160;';
 295                         }
 296
 297                         if ( $this->mOldRev->isMinor() ) {
 298                                 $oldminor = ChangesList::flag( 'minor' );
 299                         } else {
 300                                 $oldminor = '';
 301                         }
 302
 303                         $ldel = $this->revisionDeleteLink( $this->mOldRev );
 304                         $oldRevisionHeader = $this->getRevisionHeader( $this->mOldRev, 'complete' );
 305
 306                         $oldHeader = '<div id="mw-diff-otitle1"><strong>' . $oldRevisionHeader . '</strong></div>' .
 307                                 '<div id="mw-diff-otitle2">' .
 308                                         Linker::revUserTools( $this->mOldRev, !$this->unhide ) . '</div>' .
 309                                 '<div id="mw-diff-otitle3">' . $oldminor .
 310                                         Linker::revComment( $this->mOldRev, !$diffOnly, !$this->unhide ) . $ldel . '</div>' .
 311                                 '<div id="mw-diff-otitle4">' . $prevlink . '</div>';
 312
 313                         if ( $this->mOldRev->isDeleted( Revision::DELETED_TEXT ) ) {
 314                                 $deleted = true; // old revisions text is hidden
 315                                 if ( $this->mOldRev->isDeleted( Revision::DELETED_RESTRICTED ) ) {
 316                                         $suppressed = true; // also suppressed
 317                                 }
 318                         }
 319
 320                         # Check if this user can see the revisions
 321                         if ( !$this->mOldRev->userCan( Revision::DELETED_TEXT, $user ) ) {
 322                                 $allowed = false;
 323                         }
 324                 }
 325
 326                 # Make "next revision link"
 327                 # Skip next link on the top revision
 328                 if ( $samePage && !$this->mNewRev->isCurrent() ) {
 329                         $nextlink = Linker::linkKnown(
 330                                 $this->mNewPage,
 331                                 $this->msg( 'nextdiff' )->escaped(),
 332                                 array( 'id' => 'differences-nextlink' ),
 333                                 array( 'diff' => 'next', 'oldid' => $this->mNewid ) + $query
 334                         );
 335                 } else {
 336                         $nextlink = '&#160;';
 337                 }
 338
 339                 if ( $this->mNewRev->isMinor() ) {
 340                         $newminor = ChangesList::flag( 'minor' );
 341                 } else {
 342                         $newminor = '';
 343                 }
 344
 345                 # Handle RevisionDelete links...
 346                 $rdel = $this->revisionDeleteLink( $this->mNewRev );
 347
 348                 # Allow extensions to define their own revision tools
 349                 wfRunHooks( 'DiffRevisionTools', array( $this->mNewRev, &$revisionTools ) );
 350                 $formattedRevisionTools = array();
 351                 // Put each one in parentheses (poor man's button)
 352                 foreach ( $revisionTools as $tool ) {
 353                         $formattedRevisionTools[] = $this->msg( 'parentheses' )->rawParams( $tool )->escaped();
 354                 }
 355                 $newRevisionHeader = $this->getRevisionHeader( $this->mNewRev, 'complete' ) . ' ' . implode( ' ', $formattedRevisionTools );
 356
 357                 $newHeader = '<div id="mw-diff-ntitle1"><strong>' . $newRevisionHeader . '</strong></div>' .
 358                         '<div id="mw-diff-ntitle2">' . Linker::revUserTools( $this->mNewRev, !$this->unhide ) .
 359                                 " $rollback</div>" .
 360                         '<div id="mw-diff-ntitle3">' . $newminor .
 361                                 Linker::revComment( $this->mNewRev, !$diffOnly, !$this->unhide ) . $rdel . '</div>' .
 362                         '<div id="mw-diff-ntitle4">' . $nextlink . $this->markPatrolledLink() . '</div>';
 363
 364                 if ( $this->mNewRev->isDeleted( Revision::DELETED_TEXT ) ) {
 365                         $deleted = true; // new revisions text is hidden
 366                         if ( $this->mNewRev->isDeleted( Revision::DELETED_RESTRICTED ) ) {
 367                                 $suppressed = true; // also suppressed
 368                         }
 369                 }
 370
 371                 # If the diff cannot be shown due to a deleted revision, then output
 372                 # the diff header and links to unhide (if available)...
 373                 if ( $deleted && ( !$this->unhide || !$allowed ) ) {
 374                         $this->showDiffStyle();
 375                         $multi = $this->getMultiNotice();
 376                         $out->addHTML( $this->addHeader( '', $oldHeader, $newHeader, $multi ) );
 377                         if ( !$allowed ) {
 378                                 $msg = $suppressed ? 'rev-suppressed-no-diff' : 'rev-deleted-no-diff';
 379                                 # Give explanation for why revision is not visible
 380                                 $out->wrapWikiMsg( "<div id='mw-$msg' class='mw-warning plainlinks'>\n$1\n</div>\n",
 381                                         array( $msg ) );
 382                         } else {
 383                                 # Give explanation and add a link to view the diff...
 384                                 $link = $this->getTitle()->getFullURL( $this->getRequest()->appendQueryValue( 'unhide', '1', true ) );
 385                                 $msg = $suppressed ? 'rev-suppressed-unhide-diff' : 'rev-deleted-unhide-diff';
 386                                 $out->wrapWikiMsg( "<div id='mw-$msg' class='mw-warning plainlinks'>\n$1\n</div>\n", array( $msg, $link ) );
 387                         }
 388                 # Otherwise, output a regular diff...
 389                 } else {
 390                         # Add deletion notice if the user is viewing deleted content
 391                         $notice = '';
 392                         if ( $deleted ) {
 393                                 $msg = $suppressed ? 'rev-suppressed-diff-view' : 'rev-deleted-diff-view';
 394                                 $notice = "<div id='mw-$msg' class='mw-warning plainlinks'>\n" . $this->msg( $msg )->parse() . "</div>\n";
 395                         }
 396                         $this->showDiff( $oldHeader, $newHeader, $notice );
 397                         if ( !$diffOnly ) {
 398                                 $this->renderNewRevision();
 399                         }
 400                 }
 401                 wfProfileOut( __METHOD__ );
 402         }
 403
 404         /**
 405          * Get a link to mark the change as patrolled, or '' if there's either no
 406          * revision to patrol or the user is not allowed to to it.
 407          * Side effect: When the patrol link is build, this method will call
 408          * OutputPage::preventClickjacking() and load mediawiki.page.patrol.ajax.
 409          *
 410          * @return String
 411          */
 412         protected function markPatrolledLink() {
 413                 global $wgUseRCPatrol, $wgRCMaxAge, $wgEnableAPI, $wgEnableWriteAPI;
 414                 $cache = wfGetMainCache();
 415
 416                 if ( $this->mMarkPatrolledLink === null ) {
 417                         // Prepare a change patrol link, if applicable
 418                         if (
 419                                 // Is patrolling enabled and the user allowed to?
 420                                 $wgUseRCPatrol && $this->mNewPage->quickUserCan( 'patrol', $this->getUser() ) &&
 421                                 // Only do this if the revision isn't more than 6 hours older
 422                                 // than the Max RC age (6h because the RC might not be cleaned out regularly)
 423                                 RecentChange::isInRCLifespan( $this->mNewRev->getTimestamp(), 21600 ) &&
 424                                 // Maybe the result is cached
 425                                 !$cache->get( wfMemcKey( 'NotPatrollableRevId', $this->mNewid ) )
 426                         ) {
 427                                 // Look for an unpatrolled change corresponding to this diff
 428
 429                                 $db = wfGetDB( DB_SLAVE );
 430                                 $change = RecentChange::newFromConds(
 431                                         array(
 432                                                 'rc_timestamp' => $db->timestamp( $this->mNewRev->getTimestamp() ),
 433                                                 'rc_this_oldid' => $this->mNewid,
 434                                                 'rc_patrolled' => 0
 435                                         ),
 436                                         __METHOD__,
 437                                         array( 'USE INDEX' => 'rc_timestamp' )
 438                                 );
 439
 440                                 if ( $change ) {
 441                                         $rcid = $change->getAttribute( 'rc_id' );
 442                                 } else {
 443                                         // None found
 444                                         $rcid = 0;
 445                                 }
 446                                 // Build the link
 447                                 if ( $rcid ) {
 448                                         $this->getOutput()->preventClickjacking();
 449                                         if ( $wgEnableAPI && $wgEnableWriteAPI
 450                                                 && $this->getUser()->isAllowed( 'writeapi' )
 451                                         ) {
 452                                                 $this->getOutput()->addModules( 'mediawiki.page.patrol.ajax' );
 453                                         }
 454
 455                                         $token = $this->getUser()->getEditToken( $rcid );
 456                                         $this->mMarkPatrolledLink = ' <span class="patrollink">[' . Linker::linkKnown(
 457                                                 $this->mNewPage,
 458                                                 $this->msg( 'markaspatrolleddiff' )->escaped(),
 459                                                 array(),
 460                                                 array(
 461                                                         'action' => 'markpatrolled',
 462                                                         'rcid' => $rcid,
 463                                                         'token' => $token,
 464                                                 )
 465                                         ) . ']</span>';
 466                                 } else {
 467                                         $cache->set( wfMemcKey( 'NotPatrollableRevId', $this->mNewid ), '1', $wgRCMaxAge );
 468                                         $this->mMarkPatrolledLink = '';
 469                                 }
 470                         } else {
 471                                 $this->mMarkPatrolledLink = '';
 472                         }
 473                 }
 474
 475                 return $this->mMarkPatrolledLink;
 476         }
 477
 478         /**
 479          * @param $rev Revision
 480          * @return String
 481          */
 482         protected function revisionDeleteLink( $rev ) {
 483                 $link = Linker::getRevDeleteLink( $this->getUser(), $rev, $rev->getTitle() );
 484                 if ( $link !== '' ) {
 485                         $link = '&#160;&#160;&#160;' . $link . ' ';
 486                 }
 487                 return $link;
 488         }
 489
 490         /**
 491          * Show the new revision of the page.
 492          */
 493         function renderNewRevision() {
 494                 wfProfileIn( __METHOD__ );
 495                 $out = $this->getOutput();
 496                 $revHeader = $this->getRevisionHeader( $this->mNewRev );
 497                 # Add "current version as of X" title
 498                 $out->addHTML( "<hr class='diff-hr' />
 499                 <h2 class='diff-currentversion-title'>{$revHeader}</h2>\n" );
 500                 # Page content may be handled by a hooked call instead...
 501                 if ( wfRunHooks( 'ArticleContentOnDiff', array( $this, $out ) ) ) {
 502                         $this->loadNewText();
 503                         $out->setRevisionId( $this->mNewid );
 504                         $out->setRevisionTimestamp( $this->mNewRev->getTimestamp() );
 505                         $out->setArticleFlag( true );
 506
 507                         // NOTE: only needed for B/C: custom rendering of JS/CSS via hook
 508                         if ( $this->mNewPage->isCssJsSubpage() || $this->mNewPage->isCssOrJsPage() ) {
 509                                 // Stolen from Article::view --AG 2007-10-11
 510                                 // Give hooks a chance to customise the output
 511                                 // @todo standardize this crap into one function
 512                                 if ( ContentHandler::runLegacyHooks( 'ShowRawCssJs', array( $this->mNewContent, $this->mNewPage, $out ) ) ) {
 513                                         // NOTE: deprecated hook, B/C only
 514                                         // use the content object's own rendering
 515                                         $cnt = $this->mNewRev->getContent();
 516                                         $po = $cnt ? $cnt->getParserOutput( $this->mNewRev->getTitle(), $this->mNewRev->getId() ) : null;
 517                                         $txt = $po ? $po->getText() : '';
 518                                         $out->addHTML( $txt );
 519                                 }
 520                         } elseif ( !wfRunHooks( 'ArticleContentViewCustom', array( $this->mNewContent, $this->mNewPage, $out ) ) ) {
 521                                 // Handled by extension
 522                         } elseif ( !ContentHandler::runLegacyHooks( 'ArticleViewCustom', array( $this->mNewContent, $this->mNewPage, $out ) ) ) {
 523                                 // NOTE: deprecated hook, B/C only
 524                                 // Handled by extension
 525                         } else {
 526                                 // Normal page
 527                                 if ( $this->getTitle()->equals( $this->mNewPage ) ) {
 528                                         // If the Title stored in the context is the same as the one
 529                                         // of the new revision, we can use its associated WikiPage
 530                                         // object.
 531                                         $wikiPage = $this->getWikiPage();
 532                                 } else {
 533                                         // Otherwise we need to create our own WikiPage object
 534                                         $wikiPage = WikiPage::factory( $this->mNewPage );
 535                                 }
 536
 537                                 $parserOutput = $this->getParserOutput( $wikiPage, $this->mNewRev );
 538
 539                                 # Also try to load it as a redirect
 540                                 $rt = $this->mNewContent ? $this->mNewContent->getRedirectTarget() : null;
 541
 542                                 if ( $rt ) {
 543                                         $article = Article::newFromTitle( $this->mNewPage, $this->getContext() );
 544                                         $out->addHTML( $article->viewRedirect( $rt ) );
 545
 546                                         # WikiPage::getParserOutput() should not return false, but just in case
 547                                         if ( $parserOutput ) {
 548                                                 # Show categories etc.
 549                                                 $out->addParserOutputNoText( $parserOutput );
 550                                         }
 551                                 } elseif ( $parserOutput ) {
 552                                         $out->addParserOutput( $parserOutput );
 553                                 }
 554                         }
 555                 }
 556                 # Add redundant patrol link on bottom...
 557                 $out->addHTML( $this->markPatrolledLink() );
 558
 559                 wfProfileOut( __METHOD__ );
 560         }
 561
 562         protected function getParserOutput( WikiPage $page, Revision $rev ) {
 563                 $parserOptions = $page->makeParserOptions( $this->getContext() );
 564
 565                 if ( !$rev->isCurrent() || !$rev->getTitle()->quickUserCan( "edit" ) ) {
 566                         $parserOptions->setEditSection( false );
 567                 }
 568
 569                 $parserOutput = $page->getParserOutput( $parserOptions, $rev->getId() );
 570                 return $parserOutput;
 571         }
 572
 573         /**
 574          * Get the diff text, send it to the OutputPage object
 575          * Returns false if the diff could not be generated, otherwise returns true
 576          *
 577          * @return bool
 578          */
 579         function showDiff( $otitle, $ntitle, $notice = '' ) {
 580                 $diff = $this->getDiff( $otitle, $ntitle, $notice );
 581                 if ( $diff === false ) {
 582                         $this->showMissingRevision();
 583                         return false;
 584                 } else {
 585                         $this->showDiffStyle();
 586                         $this->getOutput()->addHTML( $diff );
 587                         return true;
 588                 }
 589         }
 590
 591         /**
 592          * Add style sheets and supporting JS for diff display.
 593          */
 594         function showDiffStyle() {
 595                 $this->getOutput()->addModuleStyles( 'mediawiki.action.history.diff' );
 596         }
 597
 598         /**
 599          * Get complete diff table, including header
 600          *
 601          * @param string|bool $otitle Header for old text or false
 602          * @param string|bool $ntitle Header for new text or false
 603          * @param string $notice HTML between diff header and body
 604          * @return mixed
 605          */
 606         function getDiff( $otitle, $ntitle, $notice = '' ) {
 607                 $body = $this->getDiffBody();
 608                 if ( $body === false ) {
 609                         return false;
 610                 } else {
 611                         $multi = $this->getMultiNotice();
 612                         return $this->addHeader( $body, $otitle, $ntitle, $multi, $notice );
 613                 }
 614         }
 615
 616         /**
 617          * Get the diff table body, without header
 618          *
 619          * @return mixed (string/false)
 620          */
 621         public function getDiffBody() {
 622                 global $wgMemc;
 623                 wfProfileIn( __METHOD__ );
 624                 $this->mCacheHit = true;
 625                 // Check if the diff should be hidden from this user
 626                 if ( !$this->loadRevisionData() ) {
 627                         wfProfileOut( __METHOD__ );
 628                         return false;
 629                 } elseif ( $this->mOldRev && !$this->mOldRev->userCan( Revision::DELETED_TEXT, $this->getUser() ) ) {
 630                         wfProfileOut( __METHOD__ );
 631                         return false;
 632                 } elseif ( $this->mNewRev && !$this->mNewRev->userCan( Revision::DELETED_TEXT, $this->getUser() ) ) {
 633                         wfProfileOut( __METHOD__ );
 634                         return false;
 635                 }
 636                 // Short-circuit
 637                 if ( $this->mOldRev === false || ( $this->mOldRev && $this->mNewRev
 638                         && $this->mOldRev->getID() == $this->mNewRev->getID() ) )
 639                 {
 640                         wfProfileOut( __METHOD__ );
 641                         return '';
 642                 }
 643                 // Cacheable?
 644                 $key = false;
 645                 if ( $this->mOldid && $this->mNewid ) {
 646                         $key = wfMemcKey( 'diff', 'version', MW_DIFF_VERSION,
 647                                 'oldid', $this->mOldid, 'newid', $this->mNewid );
 648                         // Try cache
 649                         if ( !$this->mRefreshCache ) {
 650                                 $difftext = $wgMemc->get( $key );
 651                                 if ( $difftext ) {
 652                                         wfIncrStats( 'diff_cache_hit' );
 653                                         $difftext = $this->localiseLineNumbers( $difftext );
 654                                         $difftext .= "\n<!-- diff cache key $key -->\n";
 655                                         wfProfileOut( __METHOD__ );
 656                                         return $difftext;
 657                                 }
 658                         } // don't try to load but save the result
 659                 }
 660                 $this->mCacheHit = false;
 661
 662                 // Loadtext is permission safe, this just clears out the diff
 663                 if ( !$this->loadText() ) {
 664                         wfProfileOut( __METHOD__ );
 665                         return false;
 666                 }
 667
 668                 $difftext = $this->generateContentDiffBody( $this->mOldContent, $this->mNewContent );
 669
 670                 // Save to cache for 7 days
 671                 if ( !wfRunHooks( 'AbortDiffCache', array( &$this ) ) ) {
 672                         wfIncrStats( 'diff_uncacheable' );
 673                 } elseif ( $key !== false && $difftext !== false ) {
 674                         wfIncrStats( 'diff_cache_miss' );
 675                         $wgMemc->set( $key, $difftext, 7 * 86400 );
 676                 } else {
 677                         wfIncrStats( 'diff_uncacheable' );
 678                 }
 679                 // Replace line numbers with the text in the user's language
 680                 if ( $difftext !== false ) {
 681                         $difftext = $this->localiseLineNumbers( $difftext );
 682                 }
 683                 wfProfileOut( __METHOD__ );
 684                 return $difftext;
 685         }
 686
 687         /**
 688          * Make sure the proper modules are loaded before we try to
 689          * make the diff
 690          */
 691         private function initDiffEngines() {
 692                 global $wgExternalDiffEngine;
 693                 if ( $wgExternalDiffEngine == 'wikidiff' && !function_exists( 'wikidiff_do_diff' ) ) {
 694                         wfProfileIn( __METHOD__ . '-php_wikidiff.so' );
 695                         wfDl( 'php_wikidiff' );
 696                         wfProfileOut( __METHOD__ . '-php_wikidiff.so' );
 697                 }
 698                 elseif ( $wgExternalDiffEngine == 'wikidiff2' && !function_exists( 'wikidiff2_do_diff' ) ) {
 699                         wfProfileIn( __METHOD__ . '-php_wikidiff2.so' );
 700                         wfDl( 'wikidiff2' );
 701                         wfProfileOut( __METHOD__ . '-php_wikidiff2.so' );
 702                 }
 703         }
 704
 705         /**
 706          * Generate a diff, no caching.
 707          *
 708          * This implementation uses generateTextDiffBody() to generate a diff based on the default
 709          * serialization of the given Content objects. This will fail if $old or $new are not
 710          * instances of TextContent.
 711          *
 712          * Subclasses may override this to provide a different rendering for the diff,
 713          * perhaps taking advantage of the content's native form. This is required for all content
 714          * models that are not text based.
 715          *
 716          * @param $old Content: old content
 717          * @param $new Content: new content
 718          *
 719          * @return bool|string
 720          * @since 1.21
 721          * @throws MWException if $old or $new are not instances of TextContent.
 722          */
 723         function generateContentDiffBody( Content $old, Content $new ) {
 724                 if ( !( $old instanceof TextContent ) ) {
 725                         throw new MWException( "Diff not implemented for " . get_class( $old ) . "; "
 726                                         . "override generateContentDiffBody to fix this." );
 727                 }
 728
 729                 if ( !( $new instanceof TextContent ) ) {
 730                         throw new MWException( "Diff not implemented for " . get_class( $new ) . "; "
 731                                 . "override generateContentDiffBody to fix this." );
 732                 }
 733
 734                 $otext = $old->serialize();
 735                 $ntext = $new->serialize();
 736
 737                 return $this->generateTextDiffBody( $otext, $ntext );
 738         }
 739
 740         /**
 741          * Generate a diff, no caching
 742          *
 743          * @param string $otext old text, must be already segmented
 744          * @param string $ntext new text, must be already segmented
 745          * @return bool|string
 746          * @deprecated since 1.21, use generateContentDiffBody() instead!
 747          */
 748         function generateDiffBody( $otext, $ntext ) {
 749                 ContentHandler::deprecated( __METHOD__, "1.21" );
 750
 751                 return $this->generateTextDiffBody( $otext, $ntext );
 752         }
 753
 754         /**
 755          * Generate a diff, no caching
 756          *
 757          * @todo move this to TextDifferenceEngine, make DifferenceEngine abstract. At some point.
 758          *
 759          * @param string $otext old text, must be already segmented
 760          * @param string $ntext new text, must be already segmented
 761          * @return bool|string
 762          */
 763         function generateTextDiffBody( $otext, $ntext ) {
 764                 global $wgExternalDiffEngine, $wgContLang;
 765
 766                 wfProfileIn( __METHOD__ );
 767
 768                 $otext = str_replace( "\r\n", "\n", $otext );
 769                 $ntext = str_replace( "\r\n", "\n", $ntext );
 770
 771                 $this->initDiffEngines();
 772
 773                 if ( $wgExternalDiffEngine == 'wikidiff' && function_exists( 'wikidiff_do_diff' ) ) {
 774                         # For historical reasons, external diff engine expects
 775                         # input text to be HTML-escaped already
 776                         $otext = htmlspecialchars ( $wgContLang->segmentForDiff( $otext ) );
 777                         $ntext = htmlspecialchars ( $wgContLang->segmentForDiff( $ntext ) );
 778                         wfProfileOut( __METHOD__ );
 779                         return $wgContLang->unsegmentForDiff( wikidiff_do_diff( $otext, $ntext, 2 ) ) .
 780                         $this->debug( 'wikidiff1' );
 781                 }
 782
 783                 if ( $wgExternalDiffEngine == 'wikidiff2' && function_exists( 'wikidiff2_do_diff' ) ) {
 784                         # Better external diff engine, the 2 may some day be dropped
 785                         # This one does the escaping and segmenting itself
 786                         wfProfileIn( 'wikidiff2_do_diff' );
 787                         $text = wikidiff2_do_diff( $otext, $ntext, 2 );
 788                         $text .= $this->debug( 'wikidiff2' );
 789                         wfProfileOut( 'wikidiff2_do_diff' );
 790                         wfProfileOut( __METHOD__ );
 791                         return $text;
 792                 }
 793                 if ( $wgExternalDiffEngine != 'wikidiff3' && $wgExternalDiffEngine !== false ) {
 794                         # Diff via the shell
 795                         $tmpDir = wfTempDir();
 796                         $tempName1 = tempnam( $tmpDir, 'diff_' );
 797                         $tempName2 = tempnam( $tmpDir, 'diff_' );
 798
 799                         $tempFile1 = fopen( $tempName1, "w" );
 800                         if ( !$tempFile1 ) {
 801                                 wfProfileOut( __METHOD__ );
 802                                 return false;
 803                         }
 804                         $tempFile2 = fopen( $tempName2, "w" );
 805                         if ( !$tempFile2 ) {
 806                                 wfProfileOut( __METHOD__ );
 807                                 return false;
 808                         }
 809                         fwrite( $tempFile1, $otext );
 810                         fwrite( $tempFile2, $ntext );
 811                         fclose( $tempFile1 );
 812                         fclose( $tempFile2 );
 813                         $cmd = wfEscapeShellArg( $wgExternalDiffEngine, $tempName1, $tempName2 );
 814                         wfProfileIn( __METHOD__ . "-shellexec" );
 815                         $difftext = wfShellExec( $cmd );
 816                         $difftext .= $this->debug( "external $wgExternalDiffEngine" );
 817                         wfProfileOut( __METHOD__ . "-shellexec" );
 818                         unlink( $tempName1 );
 819                         unlink( $tempName2 );
 820                         wfProfileOut( __METHOD__ );
 821                         return $difftext;
 822                 }
 823
 824                 # Native PHP diff
 825                 $ota = explode( "\n", $wgContLang->segmentForDiff( $otext ) );
 826                 $nta = explode( "\n", $wgContLang->segmentForDiff( $ntext ) );
 827                 $diffs = new Diff( $ota, $nta );
 828                 $formatter = new TableDiffFormatter();
 829                 $difftext = $wgContLang->unsegmentForDiff( $formatter->format( $diffs ) ) .
 830                 wfProfileOut( __METHOD__ );
 831                 return $difftext;
 832         }
 833
 834         /**
 835          * Generate a debug comment indicating diff generating time,
 836          * server node, and generator backend.
 837          * @return string
 838          */
 839         protected function debug( $generator = "internal" ) {
 840                 global $wgShowHostnames;
 841                 if ( !$this->enableDebugComment ) {
 842                         return '';
 843                 }
 844                 $data = array( $generator );
 845                 if ( $wgShowHostnames ) {
 846                         $data[] = wfHostname();
 847                 }
 848                 $data[] = wfTimestamp( TS_DB );
 849                 return "<!-- diff generator: " .
 850                 implode( " ",
 851                 array_map(
 852                                         "htmlspecialchars",
 853                 $data ) ) .
 854                         " -->\n";
 855         }
 856
 857         /**
 858          * Replace line numbers with the text in the user's language
 859          * @return mixed
 860          */
 861         function localiseLineNumbers( $text ) {
 862                 return preg_replace_callback( '/<!--LINE (\d+)-->/',
 863                 array( &$this, 'localiseLineNumbersCb' ), $text );
 864         }
 865
 866         function localiseLineNumbersCb( $matches ) {
 867                 if ( $matches[1] === '1' && $this->mReducedLineNumbers ) {
 868                         return '';
 869                 }
 870                 return $this->msg( 'lineno' )->numParams( $matches[1] )->escaped();
 871         }
 872
 873         /**
 874          * If there are revisions between the ones being compared, return a note saying so.
 875          * @return string
 876          */
 877         function getMultiNotice() {
 878                 if ( !is_object( $this->mOldRev ) || !is_object( $this->mNewRev ) ) {
 879                         return '';
 880                 } elseif ( !$this->mOldPage->equals( $this->mNewPage ) ) {
 881                         // Comparing two different pages? Count would be meaningless.
 882                         return '';
 883                 }
 884
 885                 if ( $this->mOldRev->getTimestamp() > $this->mNewRev->getTimestamp() ) {
 886                         $oldRev = $this->mNewRev; // flip
 887                         $newRev = $this->mOldRev; // flip
 888                 } else { // normal case
 889                         $oldRev = $this->mOldRev;
 890                         $newRev = $this->mNewRev;
 891                 }
 892
 893                 $nEdits = $this->mNewPage->countRevisionsBetween( $oldRev, $newRev );
 894                 if ( $nEdits > 0 ) {
 895                         $limit = 100; // use diff-multi-manyusers if too many users
 896                         $numUsers = $this->mNewPage->countAuthorsBetween( $oldRev, $newRev, $limit );
 897                         return self::intermediateEditsMsg( $nEdits, $numUsers, $limit );
 898                 }
 899                 return ''; // nothing
 900         }
 901
 902         /**
 903          * Get a notice about how many intermediate edits and users there are
 904          * @param $numEdits int
 905          * @param $numUsers int
 906          * @param $limit int
 907          * @return string
 908          */
 909         public static function intermediateEditsMsg( $numEdits, $numUsers, $limit ) {
 910                 if ( $numUsers > $limit ) {
 911                         $msg = 'diff-multi-manyusers';
 912                         $numUsers = $limit;
 913                 } else {
 914                         $msg = 'diff-multi';
 915                 }
 916                 return wfMessage( $msg )->numParams( $numEdits, $numUsers )->parse();
 917         }
 918
 919         /**
 920          * Get a header for a specified revision.
 921          *
 922          * @param $rev Revision
 923          * @param string $complete 'complete' to get the header wrapped depending
 924          *        the visibility of the revision and a link to edit the page.
 925          * @return String HTML fragment
 926          */
 927         protected function getRevisionHeader( Revision $rev, $complete = '' ) {
 928                 $lang = $this->getLanguage();
 929                 $user = $this->getUser();
 930                 $revtimestamp = $rev->getTimestamp();
 931                 $timestamp = $lang->userTimeAndDate( $revtimestamp, $user );
 932                 $dateofrev = $lang->userDate( $revtimestamp, $user );
 933                 $timeofrev = $lang->userTime( $revtimestamp, $user );
 934
 935                 $header = $this->msg(
 936                         $rev->isCurrent() ? 'currentrev-asof' : 'revisionasof',
 937                         $timestamp,
 938                         $dateofrev,
 939                         $timeofrev
 940                 )->escaped();
 941
 942                 if ( $complete !== 'complete' ) {
 943                         return $header;
 944                 }
 945
 946                 $title = $rev->getTitle();
 947
 948                 $header = Linker::linkKnown( $title, $header, array(),
 949                         array( 'oldid' => $rev->getID() ) );
 950
 951                 if ( $rev->userCan( Revision::DELETED_TEXT, $user ) ) {
 952                         $editQuery = array( 'action' => 'edit' );
 953                         if ( !$rev->isCurrent() ) {
 954                                 $editQuery['oldid'] = $rev->getID();
 955                         }
 956
 957                         $msg = $this->msg( $title->quickUserCan( 'edit', $user ) ? 'editold' : 'viewsourceold' )->escaped();
 958                         $header .= ' ' . $this->msg( 'parentheses' )->rawParams(
 959                                 Linker::linkKnown( $title, $msg, array(), $editQuery ) )->plain();
 960                         if ( $rev->isDeleted( Revision::DELETED_TEXT ) ) {
 961                                 $header = Html::rawElement( 'span', array( 'class' => 'history-deleted' ), $header );
 962                         }
 963                 } else {
 964                         $header = Html::rawElement( 'span', array( 'class' => 'history-deleted' ), $header );
 965                 }
 966
 967                 return $header;
 968         }
 969
 970         /**
 971          * Add the header to a diff body
 972          *
 973          * @return string
 974          */
 975         function addHeader( $diff, $otitle, $ntitle, $multi = '', $notice = '' ) {
 976                 // shared.css sets diff in interface language/dir, but the actual content
 977                 // is often in a different language, mostly the page content language/dir
 978                 $tableClass = 'diff diff-contentalign-' . htmlspecialchars( $this->getDiffLang()->alignStart() );
 979                 $header = "<table class='$tableClass'>";
 980
 981                 if ( !$diff && !$otitle ) {
 982                         $header .= "
 983                         <tr style='vertical-align: top;'>
 984                         <td class='diff-ntitle'>{$ntitle}</td>
 985                         </tr>";
 986                         $multiColspan = 1;
 987                 } else {
 988                         if ( $diff ) { // Safari/Chrome show broken output if cols not used
 989                                 $header .= "
 990                                 <col class='diff-marker' />
 991                                 <col class='diff-content' />
 992                                 <col class='diff-marker' />
 993                                 <col class='diff-content' />";
 994                                 $colspan = 2;
 995                                 $multiColspan = 4;
 996                         } else {
 997                                 $colspan = 1;
 998                                 $multiColspan = 2;
 999                         }
1000                         $header .= "
1001                         <tr style='vertical-align: top;'>
1002                         <td colspan='$colspan' class='diff-otitle'>{$otitle}</td>
1003                         <td colspan='$colspan' class='diff-ntitle'>{$ntitle}</td>
1004                         </tr>";
1005                 }
1006
1007                 if ( $multi != '' ) {
1008                         $header .= "<tr><td colspan='{$multiColspan}' style='text-align: center;' class='diff-multi'>{$multi}</td></tr>";
1009                 }
1010                 if ( $notice != '' ) {
1011                         $header .= "<tr><td colspan='{$multiColspan}' style='text-align: center;'>{$notice}</td></tr>";
1012                 }
1013
1014                 return $header . $diff . "</table>";
1015         }
1016
1017         /**
1018          * Use specified text instead of loading from the database
1019          * @deprecated since 1.21, use setContent() instead.
1020          */
1021         function setText( $oldText, $newText ) {
1022                 ContentHandler::deprecated( __METHOD__, "1.21" );
1023
1024                 $oldContent = ContentHandler::makeContent( $oldText, $this->getTitle() );
1025                 $newContent = ContentHandler::makeContent( $newText, $this->getTitle() );
1026
1027                 $this->setContent( $oldContent, $newContent );
1028         }
1029
1030         /**
1031          * Use specified text instead of loading from the database
1032          * @since 1.21
1033          */
1034         function setContent( Content $oldContent, Content $newContent ) {
1035                 $this->mOldContent = $oldContent;
1036                 $this->mNewContent = $newContent;
1037
1038                 $this->mTextLoaded = 2;
1039                 $this->mRevisionsLoaded = true;
1040         }
1041
1042         /**
1043          * Set the language in which the diff text is written
1044          * (Defaults to page content language).
1045          * @since 1.19
1046          */
1047         function setTextLanguage( $lang ) {
1048                 $this->mDiffLang = wfGetLangObj( $lang );
1049         }
1050
1051         /**
1052          * Load revision IDs
1053          */
1054         private function loadRevisionIds() {
1055                 if ( $this->mRevisionsIdsLoaded ) {
1056                         return;
1057                 }
1058
1059                 $this->mRevisionsIdsLoaded = true;
1060
1061                 $old = $this->mOldid;
1062                 $new = $this->mNewid;
1063
1064                 if ( $new === 'prev' ) {
1065                         # Show diff between revision $old and the previous one.
1066                         # Get previous one from DB.
1067                         $this->mNewid = intval( $old );
1068                         $this->mOldid = $this->getTitle()->getPreviousRevisionID( $this->mNewid );
1069                 } elseif ( $new === 'next' ) {
1070                         # Show diff between revision $old and the next one.
1071                         # Get next one from DB.
1072                         $this->mOldid = intval( $old );
1073                         $this->mNewid = $this->getTitle()->getNextRevisionID( $this->mOldid );
1074                         if ( $this->mNewid === false ) {
1075                                 # if no result, NewId points to the newest old revision. The only newer
1076                                 # revision is cur, which is "0".
1077                                 $this->mNewid = 0;
1078                         }
1079                 } else {
1080                         $this->mOldid = intval( $old );
1081                         $this->mNewid = intval( $new );
1082                         wfRunHooks( 'NewDifferenceEngine', array( $this->getTitle(), &$this->mOldid, &$this->mNewid, $old, $new ) );
1083                 }
1084         }
1085
1086         /**
1087          * Load revision metadata for the specified articles. If newid is 0, then compare
1088          * the old article in oldid to the current article; if oldid is 0, then
1089          * compare the current article to the immediately previous one (ignoring the
1090          * value of newid).
1091          *
1092          * If oldid is false, leave the corresponding revision object set
1093          * to false. This is impossible via ordinary user input, and is provided for
1094          * API convenience.
1095          *
1096          * @return bool
1097          */
1098         function loadRevisionData() {
1099                 if ( $this->mRevisionsLoaded ) {
1100                         return true;
1101                 }
1102
1103                 // Whether it succeeds or fails, we don't want to try again
1104                 $this->mRevisionsLoaded = true;
1105
1106                 $this->loadRevisionIds();
1107
1108                 // Load the new revision object
1109                 $this->mNewRev = $this->mNewid
1110                         ? Revision::newFromId( $this->mNewid )
1111                         : Revision::newFromTitle( $this->getTitle(), false, Revision::READ_NORMAL );
1112
1113                 if ( !$this->mNewRev instanceof Revision ) {
1114                         return false;
1115                 }
1116
1117                 // Update the new revision ID in case it was 0 (makes life easier doing UI stuff)
1118                 $this->mNewid = $this->mNewRev->getId();
1119                 $this->mNewPage = $this->mNewRev->getTitle();
1120
1121                 // Load the old revision object
1122                 $this->mOldRev = false;
1123                 if ( $this->mOldid ) {
1124                         $this->mOldRev = Revision::newFromId( $this->mOldid );
1125                 } elseif ( $this->mOldid === 0 ) {
1126                         $rev = $this->mNewRev->getPrevious();
1127                         if ( $rev ) {
1128                                 $this->mOldid = $rev->getId();
1129                                 $this->mOldRev = $rev;
1130                         } else {
1131                                 // No previous revision; mark to show as first-version only.
1132                                 $this->mOldid = false;
1133                                 $this->mOldRev = false;
1134                         }
1135                 } /* elseif ( $this->mOldid === false ) leave mOldRev false; */
1136
1137                 if ( is_null( $this->mOldRev ) ) {
1138                         return false;
1139                 }
1140
1141                 if ( $this->mOldRev ) {
1142                         $this->mOldPage = $this->mOldRev->getTitle();
1143                 }
1144
1145                 return true;
1146         }
1147
1148         /**
1149          * Load the text of the revisions, as well as revision data.
1150          *
1151          * @return bool
1152          */
1153         function loadText() {
1154                 if ( $this->mTextLoaded == 2 ) {
1155                         return true;
1156                 } else {
1157                         // Whether it succeeds or fails, we don't want to try again
1158                         $this->mTextLoaded = 2;
1159                 }
1160
1161                 if ( !$this->loadRevisionData() ) {
1162                         return false;
1163                 }
1164                 if ( $this->mOldRev ) {
1165                         $this->mOldContent = $this->mOldRev->getContent( Revision::FOR_THIS_USER, $this->getUser() );
1166                         if ( $this->mOldContent === null ) {
1167                                 return false;
1168                         }
1169                 }
1170                 if ( $this->mNewRev ) {
1171                         $this->mNewContent = $this->mNewRev->getContent( Revision::FOR_THIS_USER, $this->getUser() );
1172                         if ( $this->mNewContent === null ) {
1173                                 return false;
1174                         }
1175                 }
1176                 return true;
1177         }
1178
1179         /**
1180          * Load the text of the new revision, not the old one
1181          *
1182          * @return bool
1183          */
1184         function loadNewText() {
1185                 if ( $this->mTextLoaded >= 1 ) {
1186                         return true;
1187                 } else {
1188                         $this->mTextLoaded = 1;
1189                 }
1190                 if ( !$this->loadRevisionData() ) {
1191                         return false;
1192                 }
1193                 $this->mNewContent = $this->mNewRev->getContent( Revision::FOR_THIS_USER, $this->getUser() );
1194                 return true;
1195         }
1196 }