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, $wgEnableAPI, $wgEnableWriteAPI;
 414
 415                 if ( $this->mMarkPatrolledLink === null ) {
 416                         // Prepare a change patrol link, if applicable
 417                         if (
 418                                 // Is patrolling enabled and the user allowed to?
 419                                 $wgUseRCPatrol && $this->mNewPage->quickUserCan( 'patrol', $this->getUser() ) &&
 420                                 // Only do this if the revision isn't more than 6 hours older
 421                                 // than the Max RC age (6h because the RC might not be cleaned out regularly)
 422                                 RecentChange::isInRCLifespan( $this->mNewRev->getTimestamp(), 21600 )
 423                         ) {
 424                                 // Look for an unpatrolled change corresponding to this diff
 425
 426                                 $db = wfGetDB( DB_SLAVE );
 427                                 $change = RecentChange::newFromConds(
 428                                         array(
 429                                                 'rc_timestamp' => $db->timestamp( $this->mNewRev->getTimestamp() ),
 430                                                 'rc_this_oldid' => $this->mNewid,
 431                                                 'rc_patrolled' => 0
 432                                         ),
 433                                         __METHOD__,
 434                                         array( 'USE INDEX' => 'rc_timestamp' )
 435                                 );
 436
 437                                 if ( $change ) {
 438                                         $rcid = $change->getAttribute( 'rc_id' );
 439                                 } else {
 440                                         // None found
 441                                         $rcid = 0;
 442                                 }
 443                                 // Build the link
 444                                 if ( $rcid ) {
 445                                         $this->getOutput()->preventClickjacking();
 446                                         if ( $wgEnableAPI && $wgEnableWriteAPI
 447                                                 && $this->getUser()->isAllowed( 'writeapi' )
 448                                         ) {
 449                                                 $this->getOutput()->addModules( 'mediawiki.page.patrol.ajax' );
 450                                         }
 451
 452                                         $token = $this->getUser()->getEditToken( $rcid );
 453                                         $this->mMarkPatrolledLink = ' <span class="patrollink">[' . Linker::linkKnown(
 454                                                 $this->mNewPage,
 455                                                 $this->msg( 'markaspatrolleddiff' )->escaped(),
 456                                                 array(),
 457                                                 array(
 458                                                         'action' => 'markpatrolled',
 459                                                         'rcid' => $rcid,
 460                                                         'token' => $token,
 461                                                 )
 462                                         ) . ']</span>';
 463                                 } else {
 464                                         $this->mMarkPatrolledLink = '';
 465                                 }
 466                         } else {
 467                                 $this->mMarkPatrolledLink = '';
 468                         }
 469                 }
 470
 471                 return $this->mMarkPatrolledLink;
 472         }
 473
 474         /**
 475          * @param $rev Revision
 476          * @return String
 477          */
 478         protected function revisionDeleteLink( $rev ) {
 479                 $link = Linker::getRevDeleteLink( $this->getUser(), $rev, $rev->getTitle() );
 480                 if ( $link !== '' ) {
 481                         $link = '&#160;&#160;&#160;' . $link . ' ';
 482                 }
 483                 return $link;
 484         }
 485
 486         /**
 487          * Show the new revision of the page.
 488          */
 489         function renderNewRevision() {
 490                 wfProfileIn( __METHOD__ );
 491                 $out = $this->getOutput();
 492                 $revHeader = $this->getRevisionHeader( $this->mNewRev );
 493                 # Add "current version as of X" title
 494                 $out->addHTML( "<hr class='diff-hr' />
 495                 <h2 class='diff-currentversion-title'>{$revHeader}</h2>\n" );
 496                 # Page content may be handled by a hooked call instead...
 497                 if ( wfRunHooks( 'ArticleContentOnDiff', array( $this, $out ) ) ) {
 498                         $this->loadNewText();
 499                         $out->setRevisionId( $this->mNewid );
 500                         $out->setRevisionTimestamp( $this->mNewRev->getTimestamp() );
 501                         $out->setArticleFlag( true );
 502
 503                         // NOTE: only needed for B/C: custom rendering of JS/CSS via hook
 504                         if ( $this->mNewPage->isCssJsSubpage() || $this->mNewPage->isCssOrJsPage() ) {
 505                                 // Stolen from Article::view --AG 2007-10-11
 506                                 // Give hooks a chance to customise the output
 507                                 // @todo standardize this crap into one function
 508                                 if ( ContentHandler::runLegacyHooks( 'ShowRawCssJs', array( $this->mNewContent, $this->mNewPage, $out ) ) ) {
 509                                         // NOTE: deprecated hook, B/C only
 510                                         // use the content object's own rendering
 511                                         $cnt = $this->mNewRev->getContent();
 512                                         $po = $cnt ? $cnt->getParserOutput( $this->mNewRev->getTitle(), $this->mNewRev->getId() ) : null;
 513                                         $txt = $po ? $po->getText() : '';
 514                                         $out->addHTML( $txt );
 515                                 }
 516                         } elseif ( !wfRunHooks( 'ArticleContentViewCustom', array( $this->mNewContent, $this->mNewPage, $out ) ) ) {
 517                                 // Handled by extension
 518                         } elseif ( !ContentHandler::runLegacyHooks( 'ArticleViewCustom', array( $this->mNewContent, $this->mNewPage, $out ) ) ) {
 519                                 // NOTE: deprecated hook, B/C only
 520                                 // Handled by extension
 521                         } else {
 522                                 // Normal page
 523                                 if ( $this->getTitle()->equals( $this->mNewPage ) ) {
 524                                         // If the Title stored in the context is the same as the one
 525                                         // of the new revision, we can use its associated WikiPage
 526                                         // object.
 527                                         $wikiPage = $this->getWikiPage();
 528                                 } else {
 529                                         // Otherwise we need to create our own WikiPage object
 530                                         $wikiPage = WikiPage::factory( $this->mNewPage );
 531                                 }
 532
 533                                 $parserOutput = $this->getParserOutput( $wikiPage, $this->mNewRev );
 534
 535                                 # Also try to load it as a redirect
 536                                 $rt = $this->mNewContent ? $this->mNewContent->getRedirectTarget() : null;
 537
 538                                 if ( $rt ) {
 539                                         $article = Article::newFromTitle( $this->mNewPage, $this->getContext() );
 540                                         $out->addHTML( $article->viewRedirect( $rt ) );
 541
 542                                         # WikiPage::getParserOutput() should not return false, but just in case
 543                                         if ( $parserOutput ) {
 544                                                 # Show categories etc.
 545                                                 $out->addParserOutputNoText( $parserOutput );
 546                                         }
 547                                 } elseif ( $parserOutput ) {
 548                                         $out->addParserOutput( $parserOutput );
 549                                 }
 550                         }
 551                 }
 552                 # Add redundant patrol link on bottom...
 553                 $out->addHTML( $this->markPatrolledLink() );
 554
 555                 wfProfileOut( __METHOD__ );
 556         }
 557
 558         protected function getParserOutput( WikiPage $page, Revision $rev ) {
 559                 $parserOptions = $page->makeParserOptions( $this->getContext() );
 560
 561                 if ( !$rev->isCurrent() || !$rev->getTitle()->quickUserCan( "edit" ) ) {
 562                         $parserOptions->setEditSection( false );
 563                 }
 564
 565                 $parserOutput = $page->getParserOutput( $parserOptions, $rev->getId() );
 566                 return $parserOutput;
 567         }
 568
 569         /**
 570          * Get the diff text, send it to the OutputPage object
 571          * Returns false if the diff could not be generated, otherwise returns true
 572          *
 573          * @return bool
 574          */
 575         function showDiff( $otitle, $ntitle, $notice = '' ) {
 576                 $diff = $this->getDiff( $otitle, $ntitle, $notice );
 577                 if ( $diff === false ) {
 578                         $this->showMissingRevision();
 579                         return false;
 580                 } else {
 581                         $this->showDiffStyle();
 582                         $this->getOutput()->addHTML( $diff );
 583                         return true;
 584                 }
 585         }
 586
 587         /**
 588          * Add style sheets and supporting JS for diff display.
 589          */
 590         function showDiffStyle() {
 591                 $this->getOutput()->addModuleStyles( 'mediawiki.action.history.diff' );
 592         }
 593
 594         /**
 595          * Get complete diff table, including header
 596          *
 597          * @param string|bool $otitle Header for old text or false
 598          * @param string|bool $ntitle Header for new text or false
 599          * @param string $notice HTML between diff header and body
 600          * @return mixed
 601          */
 602         function getDiff( $otitle, $ntitle, $notice = '' ) {
 603                 $body = $this->getDiffBody();
 604                 if ( $body === false ) {
 605                         return false;
 606                 } else {
 607                         $multi = $this->getMultiNotice();
 608                         return $this->addHeader( $body, $otitle, $ntitle, $multi, $notice );
 609                 }
 610         }
 611
 612         /**
 613          * Get the diff table body, without header
 614          *
 615          * @return mixed (string/false)
 616          */
 617         public function getDiffBody() {
 618                 global $wgMemc;
 619                 wfProfileIn( __METHOD__ );
 620                 $this->mCacheHit = true;
 621                 // Check if the diff should be hidden from this user
 622                 if ( !$this->loadRevisionData() ) {
 623                         wfProfileOut( __METHOD__ );
 624                         return false;
 625                 } elseif ( $this->mOldRev && !$this->mOldRev->userCan( Revision::DELETED_TEXT, $this->getUser() ) ) {
 626                         wfProfileOut( __METHOD__ );
 627                         return false;
 628                 } elseif ( $this->mNewRev && !$this->mNewRev->userCan( Revision::DELETED_TEXT, $this->getUser() ) ) {
 629                         wfProfileOut( __METHOD__ );
 630                         return false;
 631                 }
 632                 // Short-circuit
 633                 // If mOldRev is false, it means that the
 634                 if ( $this->mOldRev === false || ( $this->mOldRev && $this->mNewRev
 635                         && $this->mOldRev->getID() == $this->mNewRev->getID() ) )
 636                 {
 637                         wfProfileOut( __METHOD__ );
 638                         return '';
 639                 }
 640                 // Cacheable?
 641                 $key = false;
 642                 if ( $this->mOldid && $this->mNewid ) {
 643                         $key = wfMemcKey( 'diff', 'version', MW_DIFF_VERSION,
 644                                 'oldid', $this->mOldid, 'newid', $this->mNewid );
 645                         // Try cache
 646                         if ( !$this->mRefreshCache ) {
 647                                 $difftext = $wgMemc->get( $key );
 648                                 if ( $difftext ) {
 649                                         wfIncrStats( 'diff_cache_hit' );
 650                                         $difftext = $this->localiseLineNumbers( $difftext );
 651                                         $difftext .= "\n<!-- diff cache key $key -->\n";
 652                                         wfProfileOut( __METHOD__ );
 653                                         return $difftext;
 654                                 }
 655                         } // don't try to load but save the result
 656                 }
 657                 $this->mCacheHit = false;
 658
 659                 // Loadtext is permission safe, this just clears out the diff
 660                 if ( !$this->loadText() ) {
 661                         wfProfileOut( __METHOD__ );
 662                         return false;
 663                 }
 664
 665                 $difftext = $this->generateContentDiffBody( $this->mOldContent, $this->mNewContent );
 666
 667                 // Save to cache for 7 days
 668                 if ( !wfRunHooks( 'AbortDiffCache', array( &$this ) ) ) {
 669                         wfIncrStats( 'diff_uncacheable' );
 670                 } elseif ( $key !== false && $difftext !== false ) {
 671                         wfIncrStats( 'diff_cache_miss' );
 672                         $wgMemc->set( $key, $difftext, 7 * 86400 );
 673                 } else {
 674                         wfIncrStats( 'diff_uncacheable' );
 675                 }
 676                 // Replace line numbers with the text in the user's language
 677                 if ( $difftext !== false ) {
 678                         $difftext = $this->localiseLineNumbers( $difftext );
 679                 }
 680                 wfProfileOut( __METHOD__ );
 681                 return $difftext;
 682         }
 683
 684         /**
 685          * Make sure the proper modules are loaded before we try to
 686          * make the diff
 687          */
 688         private function initDiffEngines() {
 689                 global $wgExternalDiffEngine;
 690                 if ( $wgExternalDiffEngine == 'wikidiff' && !function_exists( 'wikidiff_do_diff' ) ) {
 691                         wfProfileIn( __METHOD__ . '-php_wikidiff.so' );
 692                         wfDl( 'php_wikidiff' );
 693                         wfProfileOut( __METHOD__ . '-php_wikidiff.so' );
 694                 }
 695                 elseif ( $wgExternalDiffEngine == 'wikidiff2' && !function_exists( 'wikidiff2_do_diff' ) ) {
 696                         wfProfileIn( __METHOD__ . '-php_wikidiff2.so' );
 697                         wfDl( 'wikidiff2' );
 698                         wfProfileOut( __METHOD__ . '-php_wikidiff2.so' );
 699                 }
 700         }
 701
 702         /**
 703          * Generate a diff, no caching.
 704          *
 705          * This implementation uses generateTextDiffBody() to generate a diff based on the default
 706          * serialization of the given Content objects. This will fail if $old or $new are not
 707          * instances of TextContent.
 708          *
 709          * Subclasses may override this to provide a different rendering for the diff,
 710          * perhaps taking advantage of the content's native form. This is required for all content
 711          * models that are not text based.
 712          *
 713          * @param $old Content: old content
 714          * @param $new Content: new content
 715          *
 716          * @return bool|string
 717          * @since 1.21
 718          * @throws MWException if $old or $new are not instances of TextContent.
 719          */
 720         function generateContentDiffBody( Content $old, Content $new ) {
 721                 if ( !( $old instanceof TextContent ) ) {
 722                         throw new MWException( "Diff not implemented for " . get_class( $old ) . "; "
 723                                         . "override generateContentDiffBody to fix this." );
 724                 }
 725
 726                 if ( !( $new instanceof TextContent ) ) {
 727                         throw new MWException( "Diff not implemented for " . get_class( $new ) . "; "
 728                                 . "override generateContentDiffBody to fix this." );
 729                 }
 730
 731                 $otext = $old->serialize();
 732                 $ntext = $new->serialize();
 733
 734                 return $this->generateTextDiffBody( $otext, $ntext );
 735         }
 736
 737         /**
 738          * Generate a diff, no caching
 739          *
 740          * @param string $otext old text, must be already segmented
 741          * @param string $ntext new text, must be already segmented
 742          * @return bool|string
 743          * @deprecated since 1.21, use generateContentDiffBody() instead!
 744          */
 745         function generateDiffBody( $otext, $ntext ) {
 746                 ContentHandler::deprecated( __METHOD__, "1.21" );
 747
 748                 return $this->generateTextDiffBody( $otext, $ntext );
 749         }
 750
 751         /**
 752          * Generate a diff, no caching
 753          *
 754          * @todo move this to TextDifferenceEngine, make DifferenceEngine abstract. At some point.
 755          *
 756          * @param string $otext old text, must be already segmented
 757          * @param string $ntext new text, must be already segmented
 758          * @return bool|string
 759          */
 760         function generateTextDiffBody( $otext, $ntext ) {
 761                 global $wgExternalDiffEngine, $wgContLang;
 762
 763                 wfProfileIn( __METHOD__ );
 764
 765                 $otext = str_replace( "\r\n", "\n", $otext );
 766                 $ntext = str_replace( "\r\n", "\n", $ntext );
 767
 768                 $this->initDiffEngines();
 769
 770                 if ( $wgExternalDiffEngine == 'wikidiff' && function_exists( 'wikidiff_do_diff' ) ) {
 771                         # For historical reasons, external diff engine expects
 772                         # input text to be HTML-escaped already
 773                         $otext = htmlspecialchars ( $wgContLang->segmentForDiff( $otext ) );
 774                         $ntext = htmlspecialchars ( $wgContLang->segmentForDiff( $ntext ) );
 775                         wfProfileOut( __METHOD__ );
 776                         return $wgContLang->unsegmentForDiff( wikidiff_do_diff( $otext, $ntext, 2 ) ) .
 777                         $this->debug( 'wikidiff1' );
 778                 }
 779
 780                 if ( $wgExternalDiffEngine == 'wikidiff2' && function_exists( 'wikidiff2_do_diff' ) ) {
 781                         # Better external diff engine, the 2 may some day be dropped
 782                         # This one does the escaping and segmenting itself
 783                         wfProfileIn( 'wikidiff2_do_diff' );
 784                         $text = wikidiff2_do_diff( $otext, $ntext, 2 );
 785                         $text .= $this->debug( 'wikidiff2' );
 786                         wfProfileOut( 'wikidiff2_do_diff' );
 787                         wfProfileOut( __METHOD__ );
 788                         return $text;
 789                 }
 790                 if ( $wgExternalDiffEngine != 'wikidiff3' && $wgExternalDiffEngine !== false ) {
 791                         # Diff via the shell
 792                         $tmpDir = wfTempDir();
 793                         $tempName1 = tempnam( $tmpDir, 'diff_' );
 794                         $tempName2 = tempnam( $tmpDir, 'diff_' );
 795
 796                         $tempFile1 = fopen( $tempName1, "w" );
 797                         if ( !$tempFile1 ) {
 798                                 wfProfileOut( __METHOD__ );
 799                                 return false;
 800                         }
 801                         $tempFile2 = fopen( $tempName2, "w" );
 802                         if ( !$tempFile2 ) {
 803                                 wfProfileOut( __METHOD__ );
 804                                 return false;
 805                         }
 806                         fwrite( $tempFile1, $otext );
 807                         fwrite( $tempFile2, $ntext );
 808                         fclose( $tempFile1 );
 809                         fclose( $tempFile2 );
 810                         $cmd = wfEscapeShellArg( $wgExternalDiffEngine, $tempName1, $tempName2 );
 811                         wfProfileIn( __METHOD__ . "-shellexec" );
 812                         $difftext = wfShellExec( $cmd );
 813                         $difftext .= $this->debug( "external $wgExternalDiffEngine" );
 814                         wfProfileOut( __METHOD__ . "-shellexec" );
 815                         unlink( $tempName1 );
 816                         unlink( $tempName2 );
 817                         wfProfileOut( __METHOD__ );
 818                         return $difftext;
 819                 }
 820
 821                 # Native PHP diff
 822                 $ota = explode( "\n", $wgContLang->segmentForDiff( $otext ) );
 823                 $nta = explode( "\n", $wgContLang->segmentForDiff( $ntext ) );
 824                 $diffs = new Diff( $ota, $nta );
 825                 $formatter = new TableDiffFormatter();
 826                 $difftext = $wgContLang->unsegmentForDiff( $formatter->format( $diffs ) ) .
 827                 wfProfileOut( __METHOD__ );
 828                 return $difftext;
 829         }
 830
 831         /**
 832          * Generate a debug comment indicating diff generating time,
 833          * server node, and generator backend.
 834          * @return string
 835          */
 836         protected function debug( $generator = "internal" ) {
 837                 global $wgShowHostnames;
 838                 if ( !$this->enableDebugComment ) {
 839                         return '';
 840                 }
 841                 $data = array( $generator );
 842                 if ( $wgShowHostnames ) {
 843                         $data[] = wfHostname();
 844                 }
 845                 $data[] = wfTimestamp( TS_DB );
 846                 return "<!-- diff generator: " .
 847                 implode( " ",
 848                 array_map(
 849                                         "htmlspecialchars",
 850                 $data ) ) .
 851                         " -->\n";
 852         }
 853
 854         /**
 855          * Replace line numbers with the text in the user's language
 856          * @return mixed
 857          */
 858         function localiseLineNumbers( $text ) {
 859                 return preg_replace_callback( '/<!--LINE (\d+)-->/',
 860                 array( &$this, 'localiseLineNumbersCb' ), $text );
 861         }
 862
 863         function localiseLineNumbersCb( $matches ) {
 864                 if ( $matches[1] === '1' && $this->mReducedLineNumbers ) {
 865                         return '';
 866                 }
 867                 return $this->msg( 'lineno' )->numParams( $matches[1] )->escaped();
 868         }
 869
 870         /**
 871          * If there are revisions between the ones being compared, return a note saying so.
 872          * @return string
 873          */
 874         function getMultiNotice() {
 875                 if ( !is_object( $this->mOldRev ) || !is_object( $this->mNewRev ) ) {
 876                         return '';
 877                 } elseif ( !$this->mOldPage->equals( $this->mNewPage ) ) {
 878                         // Comparing two different pages? Count would be meaningless.
 879                         return '';
 880                 }
 881
 882                 if ( $this->mOldRev->getTimestamp() > $this->mNewRev->getTimestamp() ) {
 883                         $oldRev = $this->mNewRev; // flip
 884                         $newRev = $this->mOldRev; // flip
 885                 } else { // normal case
 886                         $oldRev = $this->mOldRev;
 887                         $newRev = $this->mNewRev;
 888                 }
 889
 890                 $nEdits = $this->mNewPage->countRevisionsBetween( $oldRev, $newRev );
 891                 if ( $nEdits > 0 ) {
 892                         $limit = 100; // use diff-multi-manyusers if too many users
 893                         $numUsers = $this->mNewPage->countAuthorsBetween( $oldRev, $newRev, $limit );
 894                         return self::intermediateEditsMsg( $nEdits, $numUsers, $limit );
 895                 }
 896                 return ''; // nothing
 897         }
 898
 899         /**
 900          * Get a notice about how many intermediate edits and users there are
 901          * @param $numEdits int
 902          * @param $numUsers int
 903          * @param $limit int
 904          * @return string
 905          */
 906         public static function intermediateEditsMsg( $numEdits, $numUsers, $limit ) {
 907                 if ( $numUsers > $limit ) {
 908                         $msg = 'diff-multi-manyusers';
 909                         $numUsers = $limit;
 910                 } else {
 911                         $msg = 'diff-multi';
 912                 }
 913                 return wfMessage( $msg )->numParams( $numEdits, $numUsers )->parse();
 914         }
 915
 916         /**
 917          * Get a header for a specified revision.
 918          *
 919          * @param $rev Revision
 920          * @param string $complete 'complete' to get the header wrapped depending
 921          *        the visibility of the revision and a link to edit the page.
 922          * @return String HTML fragment
 923          */
 924         protected function getRevisionHeader( Revision $rev, $complete = '' ) {
 925                 $lang = $this->getLanguage();
 926                 $user = $this->getUser();
 927                 $revtimestamp = $rev->getTimestamp();
 928                 $timestamp = $lang->userTimeAndDate( $revtimestamp, $user );
 929                 $dateofrev = $lang->userDate( $revtimestamp, $user );
 930                 $timeofrev = $lang->userTime( $revtimestamp, $user );
 931
 932                 $header = $this->msg(
 933                         $rev->isCurrent() ? 'currentrev-asof' : 'revisionasof',
 934                         $timestamp,
 935                         $dateofrev,
 936                         $timeofrev
 937                 )->escaped();
 938
 939                 if ( $complete !== 'complete' ) {
 940                         return $header;
 941                 }
 942
 943                 $title = $rev->getTitle();
 944
 945                 $header = Linker::linkKnown( $title, $header, array(),
 946                         array( 'oldid' => $rev->getID() ) );
 947
 948                 if ( $rev->userCan( Revision::DELETED_TEXT, $user ) ) {
 949                         $editQuery = array( 'action' => 'edit' );
 950                         if ( !$rev->isCurrent() ) {
 951                                 $editQuery['oldid'] = $rev->getID();
 952                         }
 953
 954                         $msg = $this->msg( $title->quickUserCan( 'edit', $user ) ? 'editold' : 'viewsourceold' )->escaped();
 955                         $header .= ' ' . $this->msg( 'parentheses' )->rawParams(
 956                                 Linker::linkKnown( $title, $msg, array(), $editQuery ) )->plain();
 957                         if ( $rev->isDeleted( Revision::DELETED_TEXT ) ) {
 958                                 $header = Html::rawElement( 'span', array( 'class' => 'history-deleted' ), $header );
 959                         }
 960                 } else {
 961                         $header = Html::rawElement( 'span', array( 'class' => 'history-deleted' ), $header );
 962                 }
 963
 964                 return $header;
 965         }
 966
 967         /**
 968          * Add the header to a diff body
 969          *
 970          * @return string
 971          */
 972         function addHeader( $diff, $otitle, $ntitle, $multi = '', $notice = '' ) {
 973                 // shared.css sets diff in interface language/dir, but the actual content
 974                 // is often in a different language, mostly the page content language/dir
 975                 $tableClass = 'diff diff-contentalign-' . htmlspecialchars( $this->getDiffLang()->alignStart() );
 976                 $header = "<table class='$tableClass'>";
 977
 978                 if ( !$diff && !$otitle ) {
 979                         $header .= "
 980                         <tr style='vertical-align: top;'>
 981                         <td class='diff-ntitle'>{$ntitle}</td>
 982                         </tr>";
 983                         $multiColspan = 1;
 984                 } else {
 985                         if ( $diff ) { // Safari/Chrome show broken output if cols not used
 986                                 $header .= "
 987                                 <col class='diff-marker' />
 988                                 <col class='diff-content' />
 989                                 <col class='diff-marker' />
 990                                 <col class='diff-content' />";
 991                                 $colspan = 2;
 992                                 $multiColspan = 4;
 993                         } else {
 994                                 $colspan = 1;
 995                                 $multiColspan = 2;
 996                         }
 997                         $header .= "
 998                         <tr style='vertical-align: top;'>
 999                         <td colspan='$colspan' class='diff-otitle'>{$otitle}</td>
1000                         <td colspan='$colspan' class='diff-ntitle'>{$ntitle}</td>
1001                         </tr>";
1002                 }
1003
1004                 if ( $multi != '' ) {
1005                         $header .= "<tr><td colspan='{$multiColspan}' style='text-align: center;' class='diff-multi'>{$multi}</td></tr>";
1006                 }
1007                 if ( $notice != '' ) {
1008                         $header .= "<tr><td colspan='{$multiColspan}' style='text-align: center;'>{$notice}</td></tr>";
1009                 }
1010
1011                 return $header . $diff . "</table>";
1012         }
1013
1014         /**
1015          * Use specified text instead of loading from the database
1016          * @deprecated since 1.21, use setContent() instead.
1017          */
1018         function setText( $oldText, $newText ) {
1019                 ContentHandler::deprecated( __METHOD__, "1.21" );
1020
1021                 $oldContent = ContentHandler::makeContent( $oldText, $this->getTitle() );
1022                 $newContent = ContentHandler::makeContent( $newText, $this->getTitle() );
1023
1024                 $this->setContent( $oldContent, $newContent );
1025         }
1026
1027         /**
1028          * Use specified text instead of loading from the database
1029          * @since 1.21
1030          */
1031         function setContent( Content $oldContent, Content $newContent ) {
1032                 $this->mOldContent = $oldContent;
1033                 $this->mNewContent = $newContent;
1034
1035                 $this->mTextLoaded = 2;
1036                 $this->mRevisionsLoaded = true;
1037         }
1038
1039         /**
1040          * Set the language in which the diff text is written
1041          * (Defaults to page content language).
1042          * @since 1.19
1043          */
1044         function setTextLanguage( $lang ) {
1045                 $this->mDiffLang = wfGetLangObj( $lang );
1046         }
1047
1048         /**
1049          * Load revision IDs
1050          */
1051         private function loadRevisionIds() {
1052                 if ( $this->mRevisionsIdsLoaded ) {
1053                         return;
1054                 }
1055
1056                 $this->mRevisionsIdsLoaded = true;
1057
1058                 $old = $this->mOldid;
1059                 $new = $this->mNewid;
1060
1061                 if ( $new === 'prev' ) {
1062                         # Show diff between revision $old and the previous one.
1063                         # Get previous one from DB.
1064                         $this->mNewid = intval( $old );
1065                         $this->mOldid = $this->getTitle()->getPreviousRevisionID( $this->mNewid );
1066                 } elseif ( $new === 'next' ) {
1067                         # Show diff between revision $old and the next one.
1068                         # Get next one from DB.
1069                         $this->mOldid = intval( $old );
1070                         $this->mNewid = $this->getTitle()->getNextRevisionID( $this->mOldid );
1071                         if ( $this->mNewid === false ) {
1072                                 # if no result, NewId points to the newest old revision. The only newer
1073                                 # revision is cur, which is "0".
1074                                 $this->mNewid = 0;
1075                         }
1076                 } else {
1077                         $this->mOldid = intval( $old );
1078                         $this->mNewid = intval( $new );
1079                         wfRunHooks( 'NewDifferenceEngine', array( $this->getTitle(), &$this->mOldid, &$this->mNewid, $old, $new ) );
1080                 }
1081         }
1082
1083         /**
1084          * Load revision metadata for the specified articles. If newid is 0, then compare
1085          * the old article in oldid to the current article; if oldid is 0, then
1086          * compare the current article to the immediately previous one (ignoring the
1087          * value of newid).
1088          *
1089          * If oldid is false, leave the corresponding revision object set
1090          * to false. This is impossible via ordinary user input, and is provided for
1091          * API convenience.
1092          *
1093          * @return bool
1094          */
1095         function loadRevisionData() {
1096                 if ( $this->mRevisionsLoaded ) {
1097                         return true;
1098                 }
1099
1100                 // Whether it succeeds or fails, we don't want to try again
1101                 $this->mRevisionsLoaded = true;
1102
1103                 $this->loadRevisionIds();
1104
1105                 // Load the new revision object
1106                 $this->mNewRev = $this->mNewid
1107                         ? Revision::newFromId( $this->mNewid )
1108                         : Revision::newFromTitle( $this->getTitle(), false, Revision::READ_NORMAL );
1109
1110                 if ( !$this->mNewRev instanceof Revision ) {
1111                         return false;
1112                 }
1113
1114                 // Update the new revision ID in case it was 0 (makes life easier doing UI stuff)
1115                 $this->mNewid = $this->mNewRev->getId();
1116                 $this->mNewPage = $this->mNewRev->getTitle();
1117
1118                 // Load the old revision object
1119                 $this->mOldRev = false;
1120                 if ( $this->mOldid ) {
1121                         $this->mOldRev = Revision::newFromId( $this->mOldid );
1122                 } elseif ( $this->mOldid === 0 ) {
1123                         $rev = $this->mNewRev->getPrevious();
1124                         if ( $rev ) {
1125                                 $this->mOldid = $rev->getId();
1126                                 $this->mOldRev = $rev;
1127                         } else {
1128                                 // No previous revision; mark to show as first-version only.
1129                                 $this->mOldid = false;
1130                                 $this->mOldRev = false;
1131                         }
1132                 } /* elseif ( $this->mOldid === false ) leave mOldRev false; */
1133
1134                 if ( is_null( $this->mOldRev ) ) {
1135                         return false;
1136                 }
1137
1138                 if ( $this->mOldRev ) {
1139                         $this->mOldPage = $this->mOldRev->getTitle();
1140                 }
1141
1142                 return true;
1143         }
1144
1145         /**
1146          * Load the text of the revisions, as well as revision data.
1147          *
1148          * @return bool
1149          */
1150         function loadText() {
1151                 if ( $this->mTextLoaded == 2 ) {
1152                         return true;
1153                 } else {
1154                         // Whether it succeeds or fails, we don't want to try again
1155                         $this->mTextLoaded = 2;
1156                 }
1157
1158                 if ( !$this->loadRevisionData() ) {
1159                         return false;
1160                 }
1161                 if ( $this->mOldRev ) {
1162                         $this->mOldContent = $this->mOldRev->getContent( Revision::FOR_THIS_USER, $this->getUser() );
1163                         if ( $this->mOldContent === null ) {
1164                                 return false;
1165                         }
1166                 }
1167                 if ( $this->mNewRev ) {
1168                         $this->mNewContent = $this->mNewRev->getContent( Revision::FOR_THIS_USER, $this->getUser() );
1169                         if ( $this->mNewContent === null ) {
1170                                 return false;
1171                         }
1172                 }
1173                 return true;
1174         }
1175
1176         /**
1177          * Load the text of the new revision, not the old one
1178          *
1179          * @return bool
1180          */
1181         function loadNewText() {
1182                 if ( $this->mTextLoaded >= 1 ) {
1183                         return true;
1184                 } else {
1185                         $this->mTextLoaded = 1;
1186                 }
1187                 if ( !$this->loadRevisionData() ) {
1188                         return false;
1189                 }
1190                 $this->mNewContent = $this->mNewRev->getContent( Revision::FOR_THIS_USER, $this->getUser() );
1191                 return true;
1192         }
1193 }