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 $new String 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                 # If external diffs are enabled both globally and for the user,
 227                 # we'll use the application/x-external-editor interface to call
 228                 # an external diff tool like kompare, kdiff3, etc.
 229                 if ( ExternalEdit::useExternalEngine( $this->getContext(), 'diff' ) ) {
 230                         //TODO: come up with a good solution for non-text content here.
 231                         //      at least, the content format needs to be passed to the client somehow.
 232                         //      Currently, action=raw will just fail for non-text content.
 233
 234                         $urls = array(
 235                                 'File' => array( 'Extension' => 'wiki', 'URL' =>
 236                                         # This should be mOldPage, but it may not be set, see below.
 237                                         $this->mNewPage->getCanonicalURL( array(
 238                                                 'action' => 'raw', 'oldid' => $this->mOldid ) )
 239                                 ),
 240                                 'File2' => array( 'Extension' => 'wiki', 'URL' =>
 241                                         $this->mNewPage->getCanonicalURL( array(
 242                                                 'action' => 'raw', 'oldid' => $this->mNewid ) )
 243                                 ),
 244                         );
 245
 246                         $externalEditor = new ExternalEdit( $this->getContext(), $urls );
 247                         $externalEditor->execute();
 248
 249                         wfProfileOut( __METHOD__ );
 250                         return;
 251                 }
 252
 253                 $rollback = '';
 254                 $undoLink = '';
 255
 256                 $query = array();
 257                 # Carry over 'diffonly' param via navigation links
 258                 if ( $diffOnly != $user->getBoolOption( 'diffonly' ) ) {
 259                         $query['diffonly'] = $diffOnly;
 260                 }
 261                 # Cascade unhide param in links for easy deletion browsing
 262                 if ( $this->unhide ) {
 263                         $query['unhide'] = 1;
 264                 }
 265
 266                 # Check if one of the revisions is deleted/suppressed
 267                 $deleted = $suppressed = false;
 268                 $allowed = $this->mNewRev->userCan( Revision::DELETED_TEXT, $user );
 269
 270                 # mOldRev is false if the difference engine is called with a "vague" query for
 271                 # a diff between a version V and its previous version V' AND the version V
 272                 # is the first version of that article. In that case, V' does not exist.
 273                 if ( $this->mOldRev === false ) {
 274                         $out->setPageTitle( $this->msg( 'difference-title', $this->mNewPage->getPrefixedText() ) );
 275                         $samePage = true;
 276                         $oldHeader = '';
 277                 } else {
 278                         wfRunHooks( 'DiffViewHeader', array( $this, $this->mOldRev, $this->mNewRev ) );
 279
 280                         $sk = $this->getSkin();
 281                         if ( method_exists( $sk, 'suppressQuickbar' ) ) {
 282                                 $sk->suppressQuickbar();
 283                         }
 284
 285                         if ( $this->mNewPage->equals( $this->mOldPage ) ) {
 286                                 $out->setPageTitle( $this->msg( 'difference-title', $this->mNewPage->getPrefixedText() ) );
 287                                 $samePage = true;
 288                         } else {
 289                                 $out->setPageTitle( $this->msg( 'difference-title-multipage', $this->mOldPage->getPrefixedText(),
 290                                         $this->mNewPage->getPrefixedText() ) );
 291                                 $out->addSubtitle( $this->msg( 'difference-multipage' ) );
 292                                 $samePage = false;
 293                         }
 294
 295                         if ( $samePage && $this->mNewPage->quickUserCan( 'edit', $user ) ) {
 296                                 if ( $this->mNewRev->isCurrent() && $this->mNewPage->userCan( 'rollback', $user ) ) {
 297                                         $rollbackLink = Linker::generateRollback( $this->mNewRev, $this->getContext() );
 298                                         if ( $rollbackLink ) {
 299                                                 $out->preventClickjacking();
 300                                                 $rollback = '&#160;&#160;&#160;' . $rollbackLink;
 301                                         }
 302                                 }
 303                                 if ( !$this->mOldRev->isDeleted( Revision::DELETED_TEXT ) && !$this->mNewRev->isDeleted( Revision::DELETED_TEXT ) ) {
 304                                         $undoLink = ' ' . $this->msg( 'parentheses' )->rawParams(
 305                                                 Html::element( 'a', array(
 306                                                         'href' => $this->mNewPage->getLocalUrl( array(
 307                                                                 'action' => 'edit',
 308                                                                 'undoafter' => $this->mOldid,
 309                                                                 'undo' => $this->mNewid ) ),
 310                                                         'title' => Linker::titleAttrib( 'undo' )
 311                                                 ),
 312                                                 $this->msg( 'editundo' )->text()
 313                                         ) )->escaped();
 314                                 }
 315                         }
 316
 317                         # Make "previous revision link"
 318                         if ( $samePage && $this->mOldRev->getPrevious() ) {
 319                                 $prevlink = Linker::linkKnown(
 320                                         $this->mOldPage,
 321                                         $this->msg( 'previousdiff' )->escaped(),
 322                                         array( 'id' => 'differences-prevlink' ),
 323                                         array( 'diff' => 'prev', 'oldid' => $this->mOldid ) + $query
 324                                 );
 325                         } else {
 326                                 $prevlink = '&#160;';
 327                         }
 328
 329                         if ( $this->mOldRev->isMinor() ) {
 330                                 $oldminor = ChangesList::flag( 'minor' );
 331                         } else {
 332                                 $oldminor = '';
 333                         }
 334
 335                         $ldel = $this->revisionDeleteLink( $this->mOldRev );
 336                         $oldRevisionHeader = $this->getRevisionHeader( $this->mOldRev, 'complete' );
 337
 338                         $oldHeader = '<div id="mw-diff-otitle1"><strong>' . $oldRevisionHeader . '</strong></div>' .
 339                                 '<div id="mw-diff-otitle2">' .
 340                                         Linker::revUserTools( $this->mOldRev, !$this->unhide ) . '</div>' .
 341                                 '<div id="mw-diff-otitle3">' . $oldminor .
 342                                         Linker::revComment( $this->mOldRev, !$diffOnly, !$this->unhide ) . $ldel . '</div>' .
 343                                 '<div id="mw-diff-otitle4">' . $prevlink . '</div>';
 344
 345                         if ( $this->mOldRev->isDeleted( Revision::DELETED_TEXT ) ) {
 346                                 $deleted = true; // old revisions text is hidden
 347                                 if ( $this->mOldRev->isDeleted( Revision::DELETED_RESTRICTED ) ) {
 348                                         $suppressed = true; // also suppressed
 349                                 }
 350                         }
 351
 352                         # Check if this user can see the revisions
 353                         if ( !$this->mOldRev->userCan( Revision::DELETED_TEXT, $user ) ) {
 354                                 $allowed = false;
 355                         }
 356                 }
 357
 358                 # Make "next revision link"
 359                 # Skip next link on the top revision
 360                 if ( $samePage && !$this->mNewRev->isCurrent() ) {
 361                         $nextlink = Linker::linkKnown(
 362                                 $this->mNewPage,
 363                                 $this->msg( 'nextdiff' )->escaped(),
 364                                 array( 'id' => 'differences-nextlink' ),
 365                                 array( 'diff' => 'next', 'oldid' => $this->mNewid ) + $query
 366                         );
 367                 } else {
 368                         $nextlink = '&#160;';
 369                 }
 370
 371                 if ( $this->mNewRev->isMinor() ) {
 372                         $newminor = ChangesList::flag( 'minor' );
 373                 } else {
 374                         $newminor = '';
 375                 }
 376
 377                 # Handle RevisionDelete links...
 378                 $rdel = $this->revisionDeleteLink( $this->mNewRev );
 379                 $newRevisionHeader = $this->getRevisionHeader( $this->mNewRev, 'complete' ) . $undoLink;
 380
 381                 $newHeader = '<div id="mw-diff-ntitle1"><strong>' . $newRevisionHeader . '</strong></div>' .
 382                         '<div id="mw-diff-ntitle2">' . Linker::revUserTools( $this->mNewRev, !$this->unhide ) .
 383                                 " $rollback</div>" .
 384                         '<div id="mw-diff-ntitle3">' . $newminor .
 385                                 Linker::revComment( $this->mNewRev, !$diffOnly, !$this->unhide ) . $rdel . '</div>' .
 386                         '<div id="mw-diff-ntitle4">' . $nextlink . $this->markPatrolledLink() . '</div>';
 387
 388                 if ( $this->mNewRev->isDeleted( Revision::DELETED_TEXT ) ) {
 389                         $deleted = true; // new revisions text is hidden
 390                         if ( $this->mNewRev->isDeleted( Revision::DELETED_RESTRICTED ) )
 391                                 $suppressed = true; // also suppressed
 392                 }
 393
 394                 # If the diff cannot be shown due to a deleted revision, then output
 395                 # the diff header and links to unhide (if available)...
 396                 if ( $deleted && ( !$this->unhide || !$allowed ) ) {
 397                         $this->showDiffStyle();
 398                         $multi = $this->getMultiNotice();
 399                         $out->addHTML( $this->addHeader( '', $oldHeader, $newHeader, $multi ) );
 400                         if ( !$allowed ) {
 401                                 $msg = $suppressed ? 'rev-suppressed-no-diff' : 'rev-deleted-no-diff';
 402                                 # Give explanation for why revision is not visible
 403                                 $out->wrapWikiMsg( "<div id='mw-$msg' class='mw-warning plainlinks'>\n$1\n</div>\n",
 404                                         array( $msg ) );
 405                         } else {
 406                                 # Give explanation and add a link to view the diff...
 407                                 $link = $this->getTitle()->getFullUrl( $this->getRequest()->appendQueryValue( 'unhide', '1', true ) );
 408                                 $msg = $suppressed ? 'rev-suppressed-unhide-diff' : 'rev-deleted-unhide-diff';
 409                                 $out->wrapWikiMsg( "<div id='mw-$msg' class='mw-warning plainlinks'>\n$1\n</div>\n", array( $msg, $link ) );
 410                         }
 411                 # Otherwise, output a regular diff...
 412                 } else {
 413                         # Add deletion notice if the user is viewing deleted content
 414                         $notice = '';
 415                         if ( $deleted ) {
 416                                 $msg = $suppressed ? 'rev-suppressed-diff-view' : 'rev-deleted-diff-view';
 417                                 $notice = "<div id='mw-$msg' class='mw-warning plainlinks'>\n" . $this->msg( $msg )->parse() . "</div>\n";
 418                         }
 419                         $this->showDiff( $oldHeader, $newHeader, $notice );
 420                         if ( !$diffOnly ) {
 421                                 $this->renderNewRevision();
 422                         }
 423                 }
 424                 wfProfileOut( __METHOD__ );
 425         }
 426
 427         /**
 428          * Get a link to mark the change as patrolled, or '' if there's either no
 429          * revision to patrol or the user is not allowed to to it.
 430          * Side effect: When the patrol link is build, this method will call
 431          * OutputPage::preventClickjacking() and load mediawiki.page.patrol.ajax.
 432          *
 433          * @return String
 434          */
 435         protected function markPatrolledLink() {
 436                 global $wgUseRCPatrol;
 437
 438                 if ( $this->mMarkPatrolledLink === null ) {
 439                         // Prepare a change patrol link, if applicable
 440                         if ( $wgUseRCPatrol && $this->mNewPage->quickUserCan( 'patrol', $this->getUser() ) ) {
 441                                 // If we've been given an explicit change identifier, use it; saves time
 442                                 if ( $this->mRcidMarkPatrolled ) {
 443                                         $rcid = $this->mRcidMarkPatrolled;
 444                                         $rc = RecentChange::newFromId( $rcid );
 445                                         // Already patrolled?
 446                                         $rcid = is_object( $rc ) && !$rc->getAttribute( 'rc_patrolled' ) ? $rcid : 0;
 447                                 } else {
 448                                         // Look for an unpatrolled change corresponding to this diff
 449                                         $db = wfGetDB( DB_SLAVE );
 450                                         $change = RecentChange::newFromConds(
 451                                                 array(
 452                                                 // Redundant user,timestamp condition so we can use the existing index
 453                                                         'rc_user_text'  => $this->mNewRev->getRawUserText(),
 454                                                         'rc_timestamp'  => $db->timestamp( $this->mNewRev->getTimestamp() ),
 455                                                         'rc_this_oldid' => $this->mNewid,
 456                                                         'rc_last_oldid' => $this->mOldid,
 457                                                         'rc_patrolled'  => 0
 458                                                 ),
 459                                                 __METHOD__
 460                                         );
 461                                         if ( $change instanceof RecentChange ) {
 462                                                 $rcid = $change->mAttribs['rc_id'];
 463                                                 $this->mRcidMarkPatrolled = $rcid;
 464                                         } else {
 465                                                 // None found
 466                                                 $rcid = 0;
 467                                         }
 468                                 }
 469                                 // Build the link
 470                                 if ( $rcid ) {
 471                                         $this->getOutput()->preventClickjacking();
 472                                         $this->getOutput()->addModules( 'mediawiki.page.patrol.ajax' );
 473
 474                                         $token = $this->getUser()->getEditToken( $rcid );
 475                                         $this->mMarkPatrolledLink = ' <span class="patrollink">[' . Linker::linkKnown(
 476                                                 $this->mNewPage,
 477                                                 $this->msg( 'markaspatrolleddiff' )->escaped(),
 478                                                 array(),
 479                                                 array(
 480                                                         'action' => 'markpatrolled',
 481                                                         'rcid' => $rcid,
 482                                                         'token' => $token,
 483                                                 )
 484                                         ) . ']</span>';
 485                                 } else {
 486                                         $this->mMarkPatrolledLink = '';
 487                                 }
 488                         } else {
 489                                 $this->mMarkPatrolledLink = '';
 490                         }
 491                 }
 492
 493                 return $this->mMarkPatrolledLink;
 494         }
 495
 496         /**
 497          * @param $rev Revision
 498          * @return String
 499          */
 500         protected function revisionDeleteLink( $rev ) {
 501                 $link = Linker::getRevDeleteLink( $this->getUser(), $rev, $rev->getTitle() );
 502                 if ( $link !== '' ) {
 503                         $link = '&#160;&#160;&#160;' . $link . ' ';
 504                 }
 505                 return $link;
 506         }
 507
 508         /**
 509          * Show the new revision of the page.
 510          */
 511         function renderNewRevision() {
 512                 wfProfileIn( __METHOD__ );
 513                 $out = $this->getOutput();
 514                 $revHeader = $this->getRevisionHeader( $this->mNewRev );
 515                 # Add "current version as of X" title
 516                 $out->addHTML( "<hr class='diff-hr' />
 517                 <h2 class='diff-currentversion-title'>{$revHeader}</h2>\n" );
 518                 # Page content may be handled by a hooked call instead...
 519                 if ( wfRunHooks( 'ArticleContentOnDiff', array( $this, $out ) ) ) {
 520                         $this->loadNewText();
 521                         $out->setRevisionId( $this->mNewid );
 522                         $out->setRevisionTimestamp( $this->mNewRev->getTimestamp() );
 523                         $out->setArticleFlag( true );
 524
 525                         // NOTE: only needed for B/C: custom rendering of JS/CSS via hook
 526                         if ( $this->mNewPage->isCssJsSubpage() || $this->mNewPage->isCssOrJsPage() ) {
 527                                 // Stolen from Article::view --AG 2007-10-11
 528                                 // Give hooks a chance to customise the output
 529                                 // @TODO: standardize this crap into one function
 530                                 if ( ContentHandler::runLegacyHooks( 'ShowRawCssJs', array( $this->mNewContent, $this->mNewPage, $out ) ) ) {
 531                                         // NOTE: deprecated hook, B/C only
 532                                         // use the content object's own rendering
 533                                         $cnt = $this->mNewRev->getContent();
 534                                         $po = $cnt ? $cnt->getParserOutput( $this->mNewRev->getTitle(), $this->mNewRev->getId() ) : null;
 535                                         $txt = $po ? $po->getText() : '';
 536                                         $out->addHTML( $txt );
 537                                 }
 538                         } elseif( !wfRunHooks( 'ArticleContentViewCustom', array( $this->mNewContent, $this->mNewPage, $out ) ) ) {
 539                                 // Handled by extension
 540                         } elseif( !ContentHandler::runLegacyHooks( 'ArticleViewCustom', array( $this->mNewContent, $this->mNewPage, $out ) ) ) {
 541                                 // NOTE: deprecated hook, B/C only
 542                                 // Handled by extension
 543                         } else {
 544                                 // Normal page
 545                                 if ( $this->getTitle()->equals( $this->mNewPage ) ) {
 546                                         // If the Title stored in the context is the same as the one
 547                                         // of the new revision, we can use its associated WikiPage
 548                                         // object.
 549                                         $wikiPage = $this->getWikiPage();
 550                                 } else {
 551                                         // Otherwise we need to create our own WikiPage object
 552                                         $wikiPage = WikiPage::factory( $this->mNewPage );
 553                                 }
 554
 555                                 $parserOutput = $this->getParserOutput( $wikiPage, $this->mNewRev );
 556
 557                                 # Also try to load it as a redirect
 558                                 $rt = $this->mNewContent ? $this->mNewContent->getRedirectTarget() : null;
 559
 560                                 if ( $rt ) {
 561                                         $article = Article::newFromTitle( $this->mNewPage, $this->getContext() );
 562                                         $out->addHTML( $article->viewRedirect( $rt ) );
 563
 564                                         # WikiPage::getParserOutput() should not return false, but just in case
 565                                         if ( $parserOutput ) {
 566                                                 # Show categories etc.
 567                                                 $out->addParserOutputNoText( $parserOutput );
 568                                         }
 569                                 } else if ( $parserOutput ) {
 570                                         $out->addParserOutput( $parserOutput );
 571                                 }
 572                         }
 573                 }
 574                 # Add redundant patrol link on bottom...
 575                 $out->addHTML( $this->markPatrolledLink() );
 576
 577                 wfProfileOut( __METHOD__ );
 578         }
 579
 580         protected function getParserOutput( WikiPage $page, Revision $rev ) {
 581                 $parserOptions = $page->makeParserOptions( $this->getContext() );
 582
 583                 if ( !$rev->isCurrent() || !$rev->getTitle()->quickUserCan( "edit" ) ) {
 584                         $parserOptions->setEditSection( false );
 585                 }
 586
 587                 $parserOutput = $page->getParserOutput( $parserOptions, $rev->getId() );
 588                 return $parserOutput;
 589         }
 590
 591         /**
 592          * Get the diff text, send it to the OutputPage object
 593          * Returns false if the diff could not be generated, otherwise returns true
 594          *
 595          * @return bool
 596          */
 597         function showDiff( $otitle, $ntitle, $notice = '' ) {
 598                 $diff = $this->getDiff( $otitle, $ntitle, $notice );
 599                 if ( $diff === false ) {
 600                         $this->showMissingRevision();
 601                         return false;
 602                 } else {
 603                         $this->showDiffStyle();
 604                         $this->getOutput()->addHTML( $diff );
 605                         return true;
 606                 }
 607         }
 608
 609         /**
 610          * Add style sheets and supporting JS for diff display.
 611          */
 612         function showDiffStyle() {
 613                 $this->getOutput()->addModuleStyles( 'mediawiki.action.history.diff' );
 614         }
 615
 616         /**
 617          * Get complete diff table, including header
 618          *
 619          * @param string|bool $otitle Header for old text or false
 620          * @param string|bool $ntitle Header for new text or false
 621          * @param $notice String: HTML between diff header and body
 622          * @return mixed
 623          */
 624         function getDiff( $otitle, $ntitle, $notice = '' ) {
 625                 $body = $this->getDiffBody();
 626                 if ( $body === false ) {
 627                         return false;
 628                 } else {
 629                         $multi = $this->getMultiNotice();
 630                         return $this->addHeader( $body, $otitle, $ntitle, $multi, $notice );
 631                 }
 632         }
 633
 634         /**
 635          * Get the diff table body, without header
 636          *
 637          * @return mixed (string/false)
 638          */
 639         public function getDiffBody() {
 640                 global $wgMemc;
 641                 wfProfileIn( __METHOD__ );
 642                 $this->mCacheHit = true;
 643                 // Check if the diff should be hidden from this user
 644                 if ( !$this->loadRevisionData() ) {
 645                         wfProfileOut( __METHOD__ );
 646                         return false;
 647                 } elseif ( $this->mOldRev && !$this->mOldRev->userCan( Revision::DELETED_TEXT, $this->getUser() ) ) {
 648                         wfProfileOut( __METHOD__ );
 649                         return false;
 650                 } elseif ( $this->mNewRev && !$this->mNewRev->userCan( Revision::DELETED_TEXT, $this->getUser() ) ) {
 651                         wfProfileOut( __METHOD__ );
 652                         return false;
 653                 }
 654                 // Short-circuit
 655                 // If mOldRev is false, it means that the
 656                 if ( $this->mOldRev === false || ( $this->mOldRev && $this->mNewRev
 657                         && $this->mOldRev->getID() == $this->mNewRev->getID() ) )
 658                 {
 659                         wfProfileOut( __METHOD__ );
 660                         return '';
 661                 }
 662                 // Cacheable?
 663                 $key = false;
 664                 if ( $this->mOldid && $this->mNewid ) {
 665                         $key = wfMemcKey( 'diff', 'version', MW_DIFF_VERSION,
 666                                 'oldid', $this->mOldid, 'newid', $this->mNewid );
 667                         // Try cache
 668                         if ( !$this->mRefreshCache ) {
 669                                 $difftext = $wgMemc->get( $key );
 670                                 if ( $difftext ) {
 671                                         wfIncrStats( 'diff_cache_hit' );
 672                                         $difftext = $this->localiseLineNumbers( $difftext );
 673                                         $difftext .= "\n<!-- diff cache key $key -->\n";
 674                                         wfProfileOut( __METHOD__ );
 675                                         return $difftext;
 676                                 }
 677                         } // don't try to load but save the result
 678                 }
 679                 $this->mCacheHit = false;
 680
 681                 // Loadtext is permission safe, this just clears out the diff
 682                 if ( !$this->loadText() ) {
 683                         wfProfileOut( __METHOD__ );
 684                         return false;
 685                 }
 686
 687                 $difftext = $this->generateContentDiffBody( $this->mOldContent, $this->mNewContent );
 688
 689                 // Save to cache for 7 days
 690                 if ( !wfRunHooks( 'AbortDiffCache', array( &$this ) ) ) {
 691                         wfIncrStats( 'diff_uncacheable' );
 692                 } elseif ( $key !== false && $difftext !== false ) {
 693                         wfIncrStats( 'diff_cache_miss' );
 694                         $wgMemc->set( $key, $difftext, 7 * 86400 );
 695                 } else {
 696                         wfIncrStats( 'diff_uncacheable' );
 697                 }
 698                 // Replace line numbers with the text in the user's language
 699                 if ( $difftext !== false ) {
 700                         $difftext = $this->localiseLineNumbers( $difftext );
 701                 }
 702                 wfProfileOut( __METHOD__ );
 703                 return $difftext;
 704         }
 705
 706         /**
 707          * Make sure the proper modules are loaded before we try to
 708          * make the diff
 709          */
 710         private function initDiffEngines() {
 711                 global $wgExternalDiffEngine;
 712                 if ( $wgExternalDiffEngine == 'wikidiff' && !function_exists( 'wikidiff_do_diff' ) ) {
 713                         wfProfileIn( __METHOD__ . '-php_wikidiff.so' );
 714                         wfDl( 'php_wikidiff' );
 715                         wfProfileOut( __METHOD__ . '-php_wikidiff.so' );
 716                 }
 717                 elseif ( $wgExternalDiffEngine == 'wikidiff2' && !function_exists( 'wikidiff2_do_diff' ) ) {
 718                         wfProfileIn( __METHOD__ . '-php_wikidiff2.so' );
 719                         wfDl( 'wikidiff2' );
 720                         wfProfileOut( __METHOD__ . '-php_wikidiff2.so' );
 721                 }
 722         }
 723
 724         /**
 725          * Generate a diff, no caching.
 726          *
 727          * This implementation uses generateTextDiffBody() to generate a diff based on the default
 728          * serialization of the given Content objects. This will fail if $old or $new are not
 729          * instances of TextContent.
 730          *
 731          * Subclasses may override this to provide a different rendering for the diff,
 732          * perhaps taking advantage of the content's native form. This is required for all content
 733          * models that are not text based.
 734          *
 735          * @param $old Content: old content
 736          * @param $new Content: new content
 737          *
 738          * @return bool|string
 739          * @since 1.21
 740          * @throws MWException if $old or $new are not instances of TextContent.
 741          */
 742         function generateContentDiffBody( Content $old, Content $new ) {
 743                 if ( !( $old instanceof TextContent ) ) {
 744                         throw new MWException( "Diff not implemented for " . get_class( $old ) . "; "
 745                                         . "override generateContentDiffBody to fix this." );
 746                 }
 747
 748                 if ( !( $new instanceof TextContent ) ) {
 749                         throw new MWException( "Diff not implemented for " . get_class( $new ) . "; "
 750                                 . "override generateContentDiffBody to fix this." );
 751                 }
 752
 753                 $otext = $old->serialize();
 754                 $ntext = $new->serialize();
 755
 756                 return $this->generateTextDiffBody( $otext, $ntext );
 757         }
 758
 759         /**
 760          * Generate a diff, no caching
 761          *
 762          * @param $otext String: old text, must be already segmented
 763          * @param $ntext String: new text, must be already segmented
 764          * @return bool|string
 765          * @deprecated since 1.21, use generateContentDiffBody() instead!
 766          */
 767         function generateDiffBody( $otext, $ntext ) {
 768                 ContentHandler::deprecated( __METHOD__, "1.21" );
 769
 770                 return $this->generateTextDiffBody( $otext, $ntext );
 771         }
 772
 773         /**
 774          * Generate a diff, no caching
 775          *
 776          * @todo move this to TextDifferenceEngine, make DifferenceEngine abstract. At some point.
 777          *
 778          * @param $otext String: old text, must be already segmented
 779          * @param $ntext String: new text, must be already segmented
 780          * @return bool|string
 781          */
 782         function generateTextDiffBody( $otext, $ntext ) {
 783                 global $wgExternalDiffEngine, $wgContLang;
 784
 785                 wfProfileIn( __METHOD__ );
 786
 787                 $otext = str_replace( "\r\n", "\n", $otext );
 788                 $ntext = str_replace( "\r\n", "\n", $ntext );
 789
 790                 $this->initDiffEngines();
 791
 792                 if ( $wgExternalDiffEngine == 'wikidiff' && function_exists( 'wikidiff_do_diff' ) ) {
 793                         # For historical reasons, external diff engine expects
 794                         # input text to be HTML-escaped already
 795                         $otext = htmlspecialchars ( $wgContLang->segmentForDiff( $otext ) );
 796                         $ntext = htmlspecialchars ( $wgContLang->segmentForDiff( $ntext ) );
 797                         wfProfileOut( __METHOD__ );
 798                         return $wgContLang->unsegmentForDiff( wikidiff_do_diff( $otext, $ntext, 2 ) ) .
 799                         $this->debug( 'wikidiff1' );
 800                 }
 801
 802                 if ( $wgExternalDiffEngine == 'wikidiff2' && function_exists( 'wikidiff2_do_diff' ) ) {
 803                         # Better external diff engine, the 2 may some day be dropped
 804                         # This one does the escaping and segmenting itself
 805                         wfProfileIn( 'wikidiff2_do_diff' );
 806                         $text = wikidiff2_do_diff( $otext, $ntext, 2 );
 807                         $text .= $this->debug( 'wikidiff2' );
 808                         wfProfileOut( 'wikidiff2_do_diff' );
 809                         wfProfileOut( __METHOD__ );
 810                         return $text;
 811                 }
 812                 if ( $wgExternalDiffEngine != 'wikidiff3' && $wgExternalDiffEngine !== false ) {
 813                         # Diff via the shell
 814                         $tmpDir = wfTempDir();
 815                         $tempName1 = tempnam( $tmpDir, 'diff_' );
 816                         $tempName2 = tempnam( $tmpDir, 'diff_' );
 817
 818                         $tempFile1 = fopen( $tempName1, "w" );
 819                         if ( !$tempFile1 ) {
 820                                 wfProfileOut( __METHOD__ );
 821                                 return false;
 822                         }
 823                         $tempFile2 = fopen( $tempName2, "w" );
 824                         if ( !$tempFile2 ) {
 825                                 wfProfileOut( __METHOD__ );
 826                                 return false;
 827                         }
 828                         fwrite( $tempFile1, $otext );
 829                         fwrite( $tempFile2, $ntext );
 830                         fclose( $tempFile1 );
 831                         fclose( $tempFile2 );
 832                         $cmd = wfEscapeShellArg( $wgExternalDiffEngine, $tempName1, $tempName2 );
 833                         wfProfileIn( __METHOD__ . "-shellexec" );
 834                         $difftext = wfShellExec( $cmd );
 835                         $difftext .= $this->debug( "external $wgExternalDiffEngine" );
 836                         wfProfileOut( __METHOD__ . "-shellexec" );
 837                         unlink( $tempName1 );
 838                         unlink( $tempName2 );
 839                         wfProfileOut( __METHOD__ );
 840                         return $difftext;
 841                 }
 842
 843                 # Native PHP diff
 844                 $ota = explode( "\n", $wgContLang->segmentForDiff( $otext ) );
 845                 $nta = explode( "\n", $wgContLang->segmentForDiff( $ntext ) );
 846                 $diffs = new Diff( $ota, $nta );
 847                 $formatter = new TableDiffFormatter();
 848                 $difftext = $wgContLang->unsegmentForDiff( $formatter->format( $diffs ) ) .
 849                 wfProfileOut( __METHOD__ );
 850                 return $difftext;
 851         }
 852
 853         /**
 854          * Generate a debug comment indicating diff generating time,
 855          * server node, and generator backend.
 856          * @return string
 857          */
 858         protected function debug( $generator = "internal" ) {
 859                 global $wgShowHostnames;
 860                 if ( !$this->enableDebugComment ) {
 861                         return '';
 862                 }
 863                 $data = array( $generator );
 864                 if ( $wgShowHostnames ) {
 865                         $data[] = wfHostname();
 866                 }
 867                 $data[] = wfTimestamp( TS_DB );
 868                 return "<!-- diff generator: " .
 869                 implode( " ",
 870                 array_map(
 871                                         "htmlspecialchars",
 872                 $data ) ) .
 873                         " -->\n";
 874         }
 875
 876         /**
 877          * Replace line numbers with the text in the user's language
 878          * @return mixed
 879          */
 880         function localiseLineNumbers( $text ) {
 881                 return preg_replace_callback( '/<!--LINE (\d+)-->/',
 882                 array( &$this, 'localiseLineNumbersCb' ), $text );
 883         }
 884
 885         function localiseLineNumbersCb( $matches ) {
 886                 if ( $matches[1] === '1' && $this->mReducedLineNumbers ) return '';
 887                 return $this->msg( 'lineno' )->numParams( $matches[1] )->escaped();
 888         }
 889
 890
 891         /**
 892          * If there are revisions between the ones being compared, return a note saying so.
 893          * @return string
 894          */
 895         function getMultiNotice() {
 896                 if ( !is_object( $this->mOldRev ) || !is_object( $this->mNewRev ) ) {
 897                         return '';
 898                 } elseif ( !$this->mOldPage->equals( $this->mNewPage ) ) {
 899                         // Comparing two different pages? Count would be meaningless.
 900                         return '';
 901                 }
 902
 903                 if ( $this->mOldRev->getTimestamp() > $this->mNewRev->getTimestamp() ) {
 904                         $oldRev = $this->mNewRev; // flip
 905                         $newRev = $this->mOldRev; // flip
 906                 } else { // normal case
 907                         $oldRev = $this->mOldRev;
 908                         $newRev = $this->mNewRev;
 909                 }
 910
 911                 $nEdits = $this->mNewPage->countRevisionsBetween( $oldRev, $newRev );
 912                 if ( $nEdits > 0 ) {
 913                         $limit = 100; // use diff-multi-manyusers if too many users
 914                         $numUsers = $this->mNewPage->countAuthorsBetween( $oldRev, $newRev, $limit );
 915                         return self::intermediateEditsMsg( $nEdits, $numUsers, $limit );
 916                 }
 917                 return ''; // nothing
 918         }
 919
 920         /**
 921          * Get a notice about how many intermediate edits and users there are
 922          * @param $numEdits int
 923          * @param $numUsers int
 924          * @param $limit int
 925          * @return string
 926          */
 927         public static function intermediateEditsMsg( $numEdits, $numUsers, $limit ) {
 928                 if ( $numUsers > $limit ) {
 929                         $msg = 'diff-multi-manyusers';
 930                         $numUsers = $limit;
 931                 } else {
 932                         $msg = 'diff-multi';
 933                 }
 934                 return wfMessage( $msg )->numParams( $numEdits, $numUsers )->parse();
 935         }
 936
 937         /**
 938          * Get a header for a specified revision.
 939          *
 940          * @param $rev Revision
 941          * @param $complete String: 'complete' to get the header wrapped depending
 942          *        the visibility of the revision and a link to edit the page.
 943          * @return String HTML fragment
 944          */
 945         protected function getRevisionHeader( Revision $rev, $complete = '' ) {
 946                 $lang = $this->getLanguage();
 947                 $user = $this->getUser();
 948                 $revtimestamp = $rev->getTimestamp();
 949                 $timestamp = $lang->userTimeAndDate( $revtimestamp, $user );
 950                 $dateofrev = $lang->userDate( $revtimestamp, $user );
 951                 $timeofrev = $lang->userTime( $revtimestamp, $user );
 952
 953                 $header = $this->msg(
 954                         $rev->isCurrent() ? 'currentrev-asof' : 'revisionasof',
 955                         $timestamp,
 956                         $dateofrev,
 957                         $timeofrev
 958                 )->escaped();
 959
 960                 if ( $complete !== 'complete' ) {
 961                         return $header;
 962                 }
 963
 964                 $title = $rev->getTitle();
 965
 966                 $header = Linker::linkKnown( $title, $header, array(),
 967                         array( 'oldid' => $rev->getID() ) );
 968
 969                 if ( $rev->userCan( Revision::DELETED_TEXT, $user ) ) {
 970                         $editQuery = array( 'action' => 'edit' );
 971                         if ( !$rev->isCurrent() ) {
 972                                 $editQuery['oldid'] = $rev->getID();
 973                         }
 974
 975                         $msg = $this->msg( $title->quickUserCan( 'edit', $user ) ? 'editold' : 'viewsourceold' )->escaped();
 976                         $header .= ' ' . $this->msg( 'parentheses' )->rawParams(
 977                                 Linker::linkKnown( $title, $msg, array(), $editQuery ) )->plain();
 978                         if ( $rev->isDeleted( Revision::DELETED_TEXT ) ) {
 979                                 $header = Html::rawElement( 'span', array( 'class' => 'history-deleted' ), $header );
 980                         }
 981                 } else {
 982                         $header = Html::rawElement( 'span', array( 'class' => 'history-deleted' ), $header );
 983                 }
 984
 985                 return $header;
 986         }
 987
 988         /**
 989          * Add the header to a diff body
 990          *
 991          * @return string
 992          */
 993         function addHeader( $diff, $otitle, $ntitle, $multi = '', $notice = '' ) {
 994                 // shared.css sets diff in interface language/dir, but the actual content
 995                 // is often in a different language, mostly the page content language/dir
 996                 $tableClass = 'diff diff-contentalign-' . htmlspecialchars( $this->getDiffLang()->alignStart() );
 997                 $header = "<table class='$tableClass'>";
 998
 999                 if ( !$diff && !$otitle ) {
1000                         $header .= "
1001                         <tr style='vertical-align: top;'>
1002                         <td class='diff-ntitle'>{$ntitle}</td>
1003                         </tr>";
1004                         $multiColspan = 1;
1005                 } else {
1006                         if ( $diff ) { // Safari/Chrome show broken output if cols not used
1007                                 $header .= "
1008                                 <col class='diff-marker' />
1009                                 <col class='diff-content' />
1010                                 <col class='diff-marker' />
1011                                 <col class='diff-content' />";
1012                                 $colspan = 2;
1013                                 $multiColspan = 4;
1014                         } else {
1015                                 $colspan = 1;
1016                                 $multiColspan = 2;
1017                         }
1018                         $header .= "
1019                         <tr style='vertical-align: top;'>
1020                         <td colspan='$colspan' class='diff-otitle'>{$otitle}</td>
1021                         <td colspan='$colspan' class='diff-ntitle'>{$ntitle}</td>
1022                         </tr>";
1023                 }
1024
1025                 if ( $multi != '' ) {
1026                         $header .= "<tr><td colspan='{$multiColspan}' style='text-align: center;' class='diff-multi'>{$multi}</td></tr>";
1027                 }
1028                 if ( $notice != '' ) {
1029                         $header .= "<tr><td colspan='{$multiColspan}' style='text-align: center;'>{$notice}</td></tr>";
1030                 }
1031
1032                 return $header . $diff . "</table>";
1033         }
1034
1035         /**
1036          * Use specified text instead of loading from the database
1037          * @deprecated since 1.21, use setContent() instead.
1038          */
1039         function setText( $oldText, $newText ) {
1040                 ContentHandler::deprecated( __METHOD__, "1.21" );
1041
1042                 $oldContent = ContentHandler::makeContent( $oldText, $this->getTitle() );
1043                 $newContent = ContentHandler::makeContent( $newText, $this->getTitle() );
1044
1045                 $this->setContent( $oldContent, $newContent );
1046         }
1047
1048         /**
1049          * Use specified text instead of loading from the database
1050          * @since 1.21
1051          */
1052         function setContent( Content $oldContent, Content $newContent ) {
1053                 $this->mOldContent = $oldContent;
1054                 $this->mNewContent = $newContent;
1055
1056                 $this->mTextLoaded = 2;
1057                 $this->mRevisionsLoaded = true;
1058         }
1059
1060         /**
1061          * Set the language in which the diff text is written
1062          * (Defaults to page content language).
1063          * @since 1.19
1064          */
1065         function setTextLanguage( $lang ) {
1066                 $this->mDiffLang = wfGetLangObj( $lang );
1067         }
1068
1069         /**
1070          * Load revision IDs
1071          */
1072         private function loadRevisionIds() {
1073                 if ( $this->mRevisionsIdsLoaded ) {
1074                         return;
1075                 }
1076
1077                 $this->mRevisionsIdsLoaded = true;
1078
1079                 $old = $this->mOldid;
1080                 $new = $this->mNewid;
1081
1082                 if ( $new === 'prev' ) {
1083                         # Show diff between revision $old and the previous one.
1084                         # Get previous one from DB.
1085                         $this->mNewid = intval( $old );
1086                         $this->mOldid = $this->getTitle()->getPreviousRevisionID( $this->mNewid );
1087                 } elseif ( $new === 'next' ) {
1088                         # Show diff between revision $old and the next one.
1089                         # Get next one from DB.
1090                         $this->mOldid = intval( $old );
1091                         $this->mNewid = $this->getTitle()->getNextRevisionID( $this->mOldid );
1092                         if ( $this->mNewid === false ) {
1093                                 # if no result, NewId points to the newest old revision. The only newer
1094                                 # revision is cur, which is "0".
1095                                 $this->mNewid = 0;
1096                         }
1097                 } else {
1098                         $this->mOldid = intval( $old );
1099                         $this->mNewid = intval( $new );
1100                         wfRunHooks( 'NewDifferenceEngine', array( $this->getTitle(), &$this->mOldid, &$this->mNewid, $old, $new ) );
1101                 }
1102         }
1103
1104         /**
1105          * Load revision metadata for the specified articles. If newid is 0, then compare
1106          * the old article in oldid to the current article; if oldid is 0, then
1107          * compare the current article to the immediately previous one (ignoring the
1108          * value of newid).
1109          *
1110          * If oldid is false, leave the corresponding revision object set
1111          * to false. This is impossible via ordinary user input, and is provided for
1112          * API convenience.
1113          *
1114          * @return bool
1115          */
1116         function loadRevisionData() {
1117                 if ( $this->mRevisionsLoaded ) {
1118                         return true;
1119                 }
1120
1121                 // Whether it succeeds or fails, we don't want to try again
1122                 $this->mRevisionsLoaded = true;
1123
1124                 $this->loadRevisionIds();
1125
1126                 // Load the new revision object
1127                 $this->mNewRev = $this->mNewid
1128                         ? Revision::newFromId( $this->mNewid )
1129                         : Revision::newFromTitle( $this->getTitle(), false, Revision::READ_NORMAL );
1130
1131                 if ( !$this->mNewRev instanceof Revision ) {
1132                         return false;
1133                 }
1134
1135                 // Update the new revision ID in case it was 0 (makes life easier doing UI stuff)
1136                 $this->mNewid = $this->mNewRev->getId();
1137                 $this->mNewPage = $this->mNewRev->getTitle();
1138
1139                 // Load the old revision object
1140                 $this->mOldRev = false;
1141                 if ( $this->mOldid ) {
1142                         $this->mOldRev = Revision::newFromId( $this->mOldid );
1143                 } elseif ( $this->mOldid === 0 ) {
1144                         $rev = $this->mNewRev->getPrevious();
1145                         if ( $rev ) {
1146                                 $this->mOldid = $rev->getId();
1147                                 $this->mOldRev = $rev;
1148                         } else {
1149                                 // No previous revision; mark to show as first-version only.
1150                                 $this->mOldid = false;
1151                                 $this->mOldRev = false;
1152                         }
1153                 } /* elseif ( $this->mOldid === false ) leave mOldRev false; */
1154
1155                 if ( is_null( $this->mOldRev ) ) {
1156                         return false;
1157                 }
1158
1159                 if ( $this->mOldRev ) {
1160                         $this->mOldPage = $this->mOldRev->getTitle();
1161                 }
1162
1163                 return true;
1164         }
1165
1166         /**
1167          * Load the text of the revisions, as well as revision data.
1168          *
1169          * @return bool
1170          */
1171         function loadText() {
1172                 if ( $this->mTextLoaded == 2 ) {
1173                         return true;
1174                 } else {
1175                         // Whether it succeeds or fails, we don't want to try again
1176                         $this->mTextLoaded = 2;
1177                 }
1178
1179                 if ( !$this->loadRevisionData() ) {
1180                         return false;
1181                 }
1182                 if ( $this->mOldRev ) {
1183                         $this->mOldContent = $this->mOldRev->getContent( Revision::FOR_THIS_USER, $this->getUser() );
1184                         if ( $this->mOldContent === null ) {
1185                                 return false;
1186                         }
1187                 }
1188                 if ( $this->mNewRev ) {
1189                         $this->mNewContent = $this->mNewRev->getContent( Revision::FOR_THIS_USER, $this->getUser() );
1190                         if ( $this->mNewContent === null ) {
1191                                 return false;
1192                         }
1193                 }
1194                 return true;
1195         }
1196
1197         /**
1198          * Load the text of the new revision, not the old one
1199          *
1200          * @return bool
1201          */
1202         function loadNewText() {
1203                 if ( $this->mTextLoaded >= 1 ) {
1204                         return true;
1205                 } else {
1206                         $this->mTextLoaded = 1;
1207                 }
1208                 if ( !$this->loadRevisionData() ) {
1209                         return false;
1210                 }
1211                 $this->mNewContent = $this->mNewRev->getContent( Revision::FOR_THIS_USER, $this->getUser() );
1212                 return true;
1213         }
1214 }