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