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         var $mOldContent, $mNewContent;
  42         protected $mDiffLang;
  43
  44         /**
  45          * @var Title
  46          */
  47         var $mOldPage, $mNewPage;
  48         var $mRcidMarkPatrolled;
  49
  50         /**
  51          * @var Revision
  52          */
  53         var $mOldRev, $mNewRev;
  54         private $mRevisionsIdsLoaded = false; // Have the revisions IDs been loaded
  55         var $mRevisionsLoaded = false; // Have the revisions been loaded
  56         var $mTextLoaded = 0; // How many text blobs have been loaded, 0, 1 or 2?
  57         var $mCacheHit = false; // Was the diff fetched from cache?
  58
  59         /**
  60          * Set this to true to add debug info to the HTML output.
  61          * Warning: this may cause RSS readers to spuriously mark articles as "new"
  62          * (bug 20601)
  63          */
  64         var $enableDebugComment = false;
  65
  66         // If true, line X is not displayed when X is 1, for example to increase
  67         // readability and conserve space with many small diffs.
  68         protected $mReducedLineNumbers = false;
  69
  70         // Link to action=markpatrolled
  71         protected $mMarkPatrolledLink = null;
  72
  73         protected $unhide = false; # show rev_deleted content if allowed
  74         /**#@-*/
  75
  76         /**
  77          * Constructor
  78          * @param $context IContextSource context to use, anything else will be ignored
  79          * @param $old Integer old ID we want to show and diff with.
  80          * @param $new String either 'prev' or 'next'.
  81          * @param $rcid Integer ??? FIXME (default 0)
  82          * @param $refreshCache boolean If set, refreshes the diff cache
  83          * @param $unhide boolean If set, allow viewing deleted revs
  84          */
  85         function __construct( $context = null, $old = 0, $new = 0, $rcid = 0,
  86                 $refreshCache = false, $unhide = false )
  87         {
  88                 if ( $context instanceof IContextSource ) {
  89                         $this->setContext( $context );
  90                 }
  91
  92                 wfDebug( "DifferenceEngine old '$old' new '$new' rcid '$rcid'\n" );
  93
  94                 $this->mOldid = $old;
  95                 $this->mNewid = $new;
  96                 $this->mRcidMarkPatrolled = intval( $rcid );  # force it to be an integer
  97                 $this->mRefreshCache = $refreshCache;
  98                 $this->unhide = $unhide;
  99         }
 100
 101         /**
 102          * @param $value bool
 103          */
 104         function setReducedLineNumbers( $value = true ) {
 105                 $this->mReducedLineNumbers = $value;
 106         }
 107
 108         /**
 109          * @return Language
 110          */
 111         function getDiffLang() {
 112                 if ( $this->mDiffLang === null ) {
 113                         # Default language in which the diff text is written.
 114                         $this->mDiffLang = $this->getTitle()->getPageLanguage();
 115                 }
 116                 return $this->mDiffLang;
 117         }
 118
 119         /**
 120          * @return bool
 121          */
 122         function wasCacheHit() {
 123                 return $this->mCacheHit;
 124         }
 125
 126         /**
 127          * @return int
 128          */
 129         function getOldid() {
 130                 $this->loadRevisionIds();
 131                 return $this->mOldid;
 132         }
 133
 134         /**
 135          * @return Bool|int
 136          */
 137         function getNewid() {
 138                 $this->loadRevisionIds();
 139                 return $this->mNewid;
 140         }
 141
 142         /**
 143          * Look up a special:Undelete link to the given deleted revision id,
 144          * as a workaround for being unable to load deleted diffs in currently.
 145          *
 146          * @param int $id revision ID
 147          * @return mixed URL or false
 148          */
 149         function deletedLink( $id ) {
 150                 if ( $this->getUser()->isAllowed( 'deletedhistory' ) ) {
 151                         $dbr = wfGetDB( DB_SLAVE );
 152                         $row = $dbr->selectRow('archive', '*',
 153                                 array( 'ar_rev_id' => $id ),
 154                                 __METHOD__ );
 155                         if ( $row ) {
 156                                 $rev = Revision::newFromArchiveRow( $row );
 157                                 $title = Title::makeTitleSafe( $row->ar_namespace, $row->ar_title );
 158                                 return SpecialPage::getTitleFor( 'Undelete' )->getFullURL( array(
 159                                         'target' => $title->getPrefixedText(),
 160                                         'timestamp' => $rev->getTimestamp()
 161                                 ));
 162                         }
 163                 }
 164                 return false;
 165         }
 166
 167         /**
 168          * Build a wikitext link toward a deleted revision, if viewable.
 169          *
 170          * @param int $id revision ID
 171          * @return string wikitext fragment
 172          */
 173         function deletedIdMarker( $id ) {
 174                 $link = $this->deletedLink( $id );
 175                 if ( $link ) {
 176                         return "[$link $id]";
 177                 } else {
 178                         return $id;
 179                 }
 180         }
 181
 182         private function showMissingRevision() {
 183                 $out = $this->getOutput();
 184
 185                 $missing = array();
 186                 if ( $this->mOldRev === null ) {
 187                         $missing[] = $this->deletedIdMarker( $this->mOldid );
 188                 }
 189                 if ( $this->mNewRev === null ) {
 190                         $missing[] = $this->deletedIdMarker( $this->mNewid );
 191                 }
 192
 193                 $out->setPageTitle( $this->msg( 'errorpagetitle' ) );
 194                 $out->addWikiMsg( 'difference-missing-revision',
 195                         $this->getLanguage()->listToText( $missing ), count( $missing ) );
 196         }
 197
 198         function showDiffPage( $diffOnly = false ) {
 199                 wfProfileIn( __METHOD__ );
 200
 201                 # Allow frames except in certain special cases
 202                 $out = $this->getOutput();
 203                 $out->allowClickjacking();
 204                 $out->setRobotPolicy( 'noindex,nofollow' );
 205
 206                 if ( !$this->loadRevisionData() ) {
 207                         $this->showMissingRevision();
 208                         wfProfileOut( __METHOD__ );
 209                         return;
 210                 }
 211
 212                 $user = $this->getUser();
 213                 $permErrors = $this->mNewPage->getUserPermissionsErrors( 'read', $user );
 214                 if ( $this->mOldPage ) { # mOldPage might not be set, see below.
 215                         $permErrors = wfMergeErrorArrays( $permErrors,
 216                                 $this->mOldPage->getUserPermissionsErrors( 'read', $user ) );
 217                 }
 218                 if ( count( $permErrors ) ) {
 219                         wfProfileOut( __METHOD__ );
 220                         throw new PermissionsError( 'read', $permErrors );
 221                 }
 222
 223                 # If external diffs are enabled both globally and for the user,
 224                 # we'll use the application/x-external-editor interface to call
 225                 # an external diff tool like kompare, kdiff3, etc.
 226                 if ( ExternalEdit::useExternalEngine( $this->getContext(), 'diff' ) ) {
 227                         //TODO: come up with a good solution for non-text content here.
 228                         //      at least, the content format needs to be passed to the client somehow.
 229                         //      Currently, action=raw will just fail for non-text content.
 230
 231                         $urls = array(
 232                                 'File' => array( 'Extension' => 'wiki', 'URL' =>
 233                                         # This should be mOldPage, but it may not be set, see below.
 234                                         $this->mNewPage->getCanonicalURL( array(
 235                                                 'action' => 'raw', 'oldid' => $this->mOldid ) )
 236                                 ),
 237                                 'File2' => array( 'Extension' => 'wiki', 'URL' =>
 238                                         $this->mNewPage->getCanonicalURL( array(
 239                                                 'action' => 'raw', 'oldid' => $this->mNewid ) )
 240                                 ),
 241                         );
 242
 243                         $externalEditor = new ExternalEdit( $this->getContext(), $urls );
 244                         $externalEditor->execute();
 245
 246                         wfProfileOut( __METHOD__ );
 247                         return;
 248                 }
 249
 250                 $rollback = '';
 251                 $undoLink = '';
 252
 253                 $query = array();
 254                 # Carry over 'diffonly' param via navigation links
 255                 if ( $diffOnly != $user->getBoolOption( 'diffonly' ) ) {
 256                         $query['diffonly'] = $diffOnly;
 257                 }
 258                 # Cascade unhide param in links for easy deletion browsing
 259                 if ( $this->unhide ) {
 260                         $query['unhide'] = 1;
 261                 }
 262
 263                 # Check if one of the revisions is deleted/suppressed
 264                 $deleted = $suppressed = false;
 265                 $allowed = $this->mNewRev->userCan( Revision::DELETED_TEXT, $user );
 266
 267                 # mOldRev is false if the difference engine is called with a "vague" query for
 268                 # a diff between a version V and its previous version V' AND the version V
 269                 # is the first version of that article. In that case, V' does not exist.
 270                 if ( $this->mOldRev === false ) {
 271                         $out->setPageTitle( $this->msg( 'difference-title', $this->mNewPage->getPrefixedText() ) );
 272                         $samePage = true;
 273                         $oldHeader = '';
 274                 } else {
 275                         wfRunHooks( 'DiffViewHeader', array( $this, $this->mOldRev, $this->mNewRev ) );
 276
 277                         $sk = $this->getSkin();
 278                         if ( method_exists( $sk, 'suppressQuickbar' ) ) {
 279                                 $sk->suppressQuickbar();
 280                         }
 281
 282                         if ( $this->mNewPage->equals( $this->mOldPage ) ) {
 283                                 $out->setPageTitle( $this->msg( 'difference-title', $this->mNewPage->getPrefixedText() ) );
 284                                 $samePage = true;
 285                         } else {
 286                                 $out->setPageTitle( $this->msg( 'difference-title-multipage', $this->mOldPage->getPrefixedText(),
 287                                         $this->mNewPage->getPrefixedText() ) );
 288                                 $out->addSubtitle( $this->msg( 'difference-multipage' ) );
 289                                 $samePage = false;
 290                         }
 291
 292                         if ( $samePage && $this->mNewPage->quickUserCan( 'edit', $user ) ) {
 293                                 if ( $this->mNewRev->isCurrent() && $this->mNewPage->userCan( 'rollback', $user ) ) {
 294                                         $out->preventClickjacking();
 295                                         $rollback = '&#160;&#160;&#160;' . Linker::generateRollback( $this->mNewRev, $this->getContext() );
 296                                 }
 297                                 if ( !$this->mOldRev->isDeleted( Revision::DELETED_TEXT ) && !$this->mNewRev->isDeleted( Revision::DELETED_TEXT ) ) {
 298                                         $undoLink = ' ' . $this->msg( 'parentheses' )->rawParams(
 299                                                 Html::element( 'a', array(
 300                                                         'href' => $this->mNewPage->getLocalUrl( array(
 301                                                                 'action' => 'edit',
 302                                                                 'undoafter' => $this->mOldid,
 303                                                                 'undo' => $this->mNewid ) ),
 304                                                         'title' => Linker::titleAttrib( 'undo' )
 305                                                 ),
 306                                                 $this->msg( 'editundo' )->text()
 307                                         ) )->escaped();
 308                                 }
 309                         }
 310
 311                         # Make "previous revision link"
 312                         if ( $samePage && $this->mOldRev->getPrevious() ) {
 313                                 $prevlink = Linker::linkKnown(
 314                                         $this->mOldPage,
 315                                         $this->msg( 'previousdiff' )->escaped(),
 316                                         array( 'id' => 'differences-prevlink' ),
 317                                         array( 'diff' => 'prev', 'oldid' => $this->mOldid ) + $query
 318                                 );
 319                         } else {
 320                                 $prevlink = '&#160;';
 321                         }
 322
 323                         if ( $this->mOldRev->isMinor() ) {
 324                                 $oldminor = ChangesList::flag( 'minor' );
 325                         } else {
 326                                 $oldminor = '';
 327                         }
 328
 329                         $ldel = $this->revisionDeleteLink( $this->mOldRev );
 330                         $oldRevisionHeader = $this->getRevisionHeader( $this->mOldRev, 'complete' );
 331
 332                         $oldHeader = '<div id="mw-diff-otitle1"><strong>' . $oldRevisionHeader . '</strong></div>' .
 333                                 '<div id="mw-diff-otitle2">' .
 334                                         Linker::revUserTools( $this->mOldRev, !$this->unhide ) . '</div>' .
 335                                 '<div id="mw-diff-otitle3">' . $oldminor .
 336                                         Linker::revComment( $this->mOldRev, !$diffOnly, !$this->unhide ) . $ldel . '</div>' .
 337                                 '<div id="mw-diff-otitle4">' . $prevlink . '</div>';
 338
 339                         if ( $this->mOldRev->isDeleted( Revision::DELETED_TEXT ) ) {
 340                                 $deleted = true; // old revisions text is hidden
 341                                 if ( $this->mOldRev->isDeleted( Revision::DELETED_RESTRICTED ) ) {
 342                                         $suppressed = true; // also suppressed
 343                                 }
 344                         }
 345
 346                         # Check if this user can see the revisions
 347                         if ( !$this->mOldRev->userCan( Revision::DELETED_TEXT, $user ) ) {
 348                                 $allowed = false;
 349                         }
 350                 }
 351
 352                 # Make "next revision link"
 353                 # Skip next link on the top revision
 354                 if ( $samePage && !$this->mNewRev->isCurrent() ) {
 355                         $nextlink = Linker::linkKnown(
 356                                 $this->mNewPage,
 357                                 $this->msg( 'nextdiff' )->escaped(),
 358                                 array( 'id' => 'differences-nextlink' ),
 359                                 array( 'diff' => 'next', 'oldid' => $this->mNewid ) + $query
 360                         );
 361                 } else {
 362                         $nextlink = '&#160;';
 363                 }
 364
 365                 if ( $this->mNewRev->isMinor() ) {
 366                         $newminor = ChangesList::flag( 'minor' );
 367                 } else {
 368                         $newminor = '';
 369                 }
 370
 371                 # Handle RevisionDelete links...
 372                 $rdel = $this->revisionDeleteLink( $this->mNewRev );
 373                 $newRevisionHeader = $this->getRevisionHeader( $this->mNewRev, 'complete' ) . $undoLink;
 374
 375                 $newHeader = '<div id="mw-diff-ntitle1"><strong>' . $newRevisionHeader . '</strong></div>' .
 376                         '<div id="mw-diff-ntitle2">' . Linker::revUserTools( $this->mNewRev, !$this->unhide ) .
 377                                 " $rollback</div>" .
 378                         '<div id="mw-diff-ntitle3">' . $newminor .
 379                                 Linker::revComment( $this->mNewRev, !$diffOnly, !$this->unhide ) . $rdel . '</div>' .
 380                         '<div id="mw-diff-ntitle4">' . $nextlink . $this->markPatrolledLink() . '</div>';
 381
 382                 if ( $this->mNewRev->isDeleted( Revision::DELETED_TEXT ) ) {
 383                         $deleted = true; // new revisions text is hidden
 384                         if ( $this->mNewRev->isDeleted( Revision::DELETED_RESTRICTED ) )
 385                                 $suppressed = true; // also suppressed
 386                 }
 387
 388                 # If the diff cannot be shown due to a deleted revision, then output
 389                 # the diff header and links to unhide (if available)...
 390                 if ( $deleted && ( !$this->unhide || !$allowed ) ) {
 391                         $this->showDiffStyle();
 392                         $multi = $this->getMultiNotice();
 393                         $out->addHTML( $this->addHeader( '', $oldHeader, $newHeader, $multi ) );
 394                         if ( !$allowed ) {
 395                                 $msg = $suppressed ? 'rev-suppressed-no-diff' : 'rev-deleted-no-diff';
 396                                 # Give explanation for why revision is not visible
 397                                 $out->wrapWikiMsg( "<div id='mw-$msg' class='mw-warning plainlinks'>\n$1\n</div>\n",
 398                                         array( $msg ) );
 399                         } else {
 400                                 # Give explanation and add a link to view the diff...
 401                                 $link = $this->getTitle()->getFullUrl( $this->getRequest()->appendQueryValue( 'unhide', '1', true ) );
 402                                 $msg = $suppressed ? 'rev-suppressed-unhide-diff' : 'rev-deleted-unhide-diff';
 403                                 $out->wrapWikiMsg( "<div id='mw-$msg' class='mw-warning plainlinks'>\n$1\n</div>\n", array( $msg, $link ) );
 404                         }
 405                 # Otherwise, output a regular diff...
 406                 } else {
 407                         # Add deletion notice if the user is viewing deleted content
 408                         $notice = '';
 409                         if ( $deleted ) {
 410                                 $msg = $suppressed ? 'rev-suppressed-diff-view' : 'rev-deleted-diff-view';
 411                                 $notice = "<div id='mw-$msg' class='mw-warning plainlinks'>\n" . $this->msg( $msg )->parse() . "</div>\n";
 412                         }
 413                         $this->showDiff( $oldHeader, $newHeader, $notice );
 414                         if ( !$diffOnly ) {
 415                                 $this->renderNewRevision();
 416                         }
 417                 }
 418                 wfProfileOut( __METHOD__ );
 419         }
 420
 421         /**
 422          * Get a link to mark the change as patrolled, or '' if there's either no
 423          * revision to patrol or the user is not allowed to to it.
 424          * Side effect: When the patrol link is build, this method will call
 425          * OutputPage::preventClickjacking() and load mediawiki.page.patrol.ajax.
 426          *
 427          * @return String
 428          */
 429         protected function markPatrolledLink() {
 430                 global $wgUseRCPatrol;
 431
 432                 if ( $this->mMarkPatrolledLink === null ) {
 433                         // Prepare a change patrol link, if applicable
 434                         if ( $wgUseRCPatrol && $this->mNewPage->quickUserCan( 'patrol', $this->getUser() ) ) {
 435                                 // If we've been given an explicit change identifier, use it; saves time
 436                                 if ( $this->mRcidMarkPatrolled ) {
 437                                         $rcid = $this->mRcidMarkPatrolled;
 438                                         $rc = RecentChange::newFromId( $rcid );
 439                                         // Already patrolled?
 440                                         $rcid = is_object( $rc ) && !$rc->getAttribute( 'rc_patrolled' ) ? $rcid : 0;
 441                                 } else {
 442                                         // Look for an unpatrolled change corresponding to this diff
 443                                         $db = wfGetDB( DB_SLAVE );
 444                                         $change = RecentChange::newFromConds(
 445                                                 array(
 446                                                 // Redundant user,timestamp condition so we can use the existing index
 447                                                         'rc_user_text'  => $this->mNewRev->getRawUserText(),
 448                                                         'rc_timestamp'  => $db->timestamp( $this->mNewRev->getTimestamp() ),
 449                                                         'rc_this_oldid' => $this->mNewid,
 450                                                         'rc_last_oldid' => $this->mOldid,
 451                                                         'rc_patrolled'  => 0
 452                                                 ),
 453                                                 __METHOD__
 454                                         );
 455                                         if ( $change instanceof RecentChange ) {
 456                                                 $rcid = $change->mAttribs['rc_id'];
 457                                                 $this->mRcidMarkPatrolled = $rcid;
 458                                         } else {
 459                                                 // None found
 460                                                 $rcid = 0;
 461                                         }
 462                                 }
 463                                 // Build the link
 464                                 if ( $rcid ) {
 465                                         $this->getOutput()->preventClickjacking();
 466                                         $this->getOutput()->addModules( 'mediawiki.page.patrol.ajax' );
 467
 468                                         $token = $this->getUser()->getEditToken( $rcid );
 469                                         $this->mMarkPatrolledLink = ' <span class="patrollink">[' . Linker::linkKnown(
 470                                                 $this->mNewPage,
 471                                                 $this->msg( 'markaspatrolleddiff' )->escaped(),
 472                                                 array(),
 473                                                 array(
 474                                                         'action' => 'markpatrolled',
 475                                                         'rcid' => $rcid,
 476                                                         'token' => $token,
 477                                                 )
 478                                         ) . ']</span>';
 479                                 } else {
 480                                         $this->mMarkPatrolledLink = '';
 481                                 }
 482                         } else {
 483                                 $this->mMarkPatrolledLink = '';
 484                         }
 485                 }
 486
 487                 return $this->mMarkPatrolledLink;
 488         }
 489
 490         /**
 491          * @param $rev Revision
 492          * @return String
 493          */
 494         protected function revisionDeleteLink( $rev ) {
 495                 $link = Linker::getRevDeleteLink( $this->getUser(), $rev, $rev->getTitle() );
 496                 if ( $link !== '' ) {
 497                         $link = '&#160;&#160;&#160;' . $link . ' ';
 498                 }
 499                 return $link;
 500         }
 501
 502         /**
 503          * Show the new revision of the page.
 504          */
 505         function renderNewRevision() {
 506                 wfProfileIn( __METHOD__ );
 507                 $out = $this->getOutput();
 508                 $revHeader = $this->getRevisionHeader( $this->mNewRev );
 509                 # Add "current version as of X" title
 510                 $out->addHTML( "<hr class='diff-hr' />
 511                 <h2 class='diff-currentversion-title'>{$revHeader}</h2>\n" );
 512                 # Page content may be handled by a hooked call instead...
 513                 if ( wfRunHooks( 'ArticleContentOnDiff', array( $this, $out ) ) ) {
 514                         $this->loadNewText();
 515                         $out->setRevisionId( $this->mNewid );
 516                         $out->setRevisionTimestamp( $this->mNewRev->getTimestamp() );
 517                         $out->setArticleFlag( true );
 518
 519                         // NOTE: only needed for B/C: custom rendering of JS/CSS via hook
 520                         if ( $this->mNewPage->isCssJsSubpage() || $this->mNewPage->isCssOrJsPage() ) {
 521                                 // Stolen from Article::view --AG 2007-10-11
 522                                 // Give hooks a chance to customise the output
 523                                 // @TODO: standardize this crap into one function
 524                                 if ( ContentHandler::runLegacyHooks( 'ShowRawCssJs', array( $this->mNewContent, $this->mNewPage, $out ) ) ) {
 525                                         // NOTE: deprecated hook, B/C only
 526                                         // use the content object's own rendering
 527                                         $cnt = $this->mNewRev->getContent();
 528                                         $po = $cnt ? $cnt->getParserOutput( $this->mNewRev->getTitle(), $this->mNewRev->getId() ) : null;
 529                                         $txt = $po ? $po->getText() : '';
 530                                         $out->addHTML( $txt );
 531                                 }
 532                         } elseif( !wfRunHooks( 'ArticleContentViewCustom', array( $this->mNewContent, $this->mNewPage, $out ) ) ) {
 533                                 // Handled by extension
 534                         } elseif( !ContentHandler::runLegacyHooks( 'ArticleViewCustom', array( $this->mNewContent, $this->mNewPage, $out ) ) ) {
 535                                 // NOTE: deprecated hook, B/C only
 536                                 // Handled by extension
 537                         } else {
 538                                 // Normal page
 539                                 if ( $this->getTitle()->equals( $this->mNewPage ) ) {
 540                                         // If the Title stored in the context is the same as the one
 541                                         // of the new revision, we can use its associated WikiPage
 542                                         // object.
 543                                         $wikiPage = $this->getWikiPage();
 544                                 } else {
 545                                         // Otherwise we need to create our own WikiPage object
 546                                         $wikiPage = WikiPage::factory( $this->mNewPage );
 547                                 }
 548
 549                                 $parserOutput = $this->getParserOutput( $wikiPage, $this->mNewRev );
 550
 551                                 # Also try to load it as a redirect
 552                                 $rt = $this->mNewContent ? $this->mNewContent->getRedirectTarget() : null;
 553
 554                                 if ( $rt ) {
 555                                         $article = Article::newFromTitle( $this->mNewPage, $this->getContext() );
 556                                         $out->addHTML( $article->viewRedirect( $rt ) );
 557
 558                                         # WikiPage::getParserOutput() should not return false, but just in case
 559                                         if ( $parserOutput ) {
 560                                                 # Show categories etc.
 561                                                 $out->addParserOutputNoText( $parserOutput );
 562                                         }
 563                                 } else if ( $parserOutput ) {
 564                                         $out->addParserOutput( $parserOutput );
 565                                 }
 566                         }
 567                 }
 568                 # Add redundant patrol link on bottom...
 569                 $out->addHTML( $this->markPatrolledLink() );
 570
 571                 wfProfileOut( __METHOD__ );
 572         }
 573
 574         protected function getParserOutput( WikiPage $page, Revision $rev ) {
 575                 $parserOptions = $page->makeParserOptions( $this->getContext() );
 576
 577                 if ( !$rev->isCurrent() || !$rev->getTitle()->quickUserCan( "edit" ) ) {
 578                         $parserOptions->setEditSection( false );
 579                 }
 580
 581                 $parserOutput = $page->getParserOutput( $parserOptions, $rev->getId() );
 582                 return $parserOutput;
 583         }
 584
 585         /**
 586          * Get the diff text, send it to the OutputPage object
 587          * Returns false if the diff could not be generated, otherwise returns true
 588          *
 589          * @return bool
 590          */
 591         function showDiff( $otitle, $ntitle, $notice = '' ) {
 592                 $diff = $this->getDiff( $otitle, $ntitle, $notice );
 593                 if ( $diff === false ) {
 594                         $this->showMissingRevision();
 595                         return false;
 596                 } else {
 597                         $this->showDiffStyle();
 598                         $this->getOutput()->addHTML( $diff );
 599                         return true;
 600                 }
 601         }
 602
 603         /**
 604          * Add style sheets and supporting JS for diff display.
 605          */
 606         function showDiffStyle() {
 607                 $this->getOutput()->addModuleStyles( 'mediawiki.action.history.diff' );
 608         }
 609
 610         /**
 611          * Get complete diff table, including header
 612          *
 613          * @param $otitle Title: old title
 614          * @param $ntitle Title: new title
 615          * @param $notice String: HTML between diff header and body
 616          * @return mixed
 617          */
 618         function getDiff( $otitle, $ntitle, $notice = '' ) {
 619                 $body = $this->getDiffBody();
 620                 if ( $body === false ) {
 621                         return false;
 622                 } else {
 623                         $multi = $this->getMultiNotice();
 624                         return $this->addHeader( $body, $otitle, $ntitle, $multi, $notice );
 625                 }
 626         }
 627
 628         /**
 629          * Get the diff table body, without header
 630          *
 631          * @return mixed (string/false)
 632          */
 633         public function getDiffBody() {
 634                 global $wgMemc;
 635                 wfProfileIn( __METHOD__ );
 636                 $this->mCacheHit = true;
 637                 // Check if the diff should be hidden from this user
 638                 if ( !$this->loadRevisionData() ) {
 639                         wfProfileOut( __METHOD__ );
 640                         return false;
 641                 } elseif ( $this->mOldRev && !$this->mOldRev->userCan( Revision::DELETED_TEXT, $this->getUser() ) ) {
 642                         wfProfileOut( __METHOD__ );
 643                         return false;
 644                 } elseif ( $this->mNewRev && !$this->mNewRev->userCan( Revision::DELETED_TEXT, $this->getUser() ) ) {
 645                         wfProfileOut( __METHOD__ );
 646                         return false;
 647                 }
 648                 // Short-circuit
 649                 // If mOldRev is false, it means that the
 650                 if ( $this->mOldRev === false || ( $this->mOldRev && $this->mNewRev
 651                         && $this->mOldRev->getID() == $this->mNewRev->getID() ) )
 652                 {
 653                         wfProfileOut( __METHOD__ );
 654                         return '';
 655                 }
 656                 // Cacheable?
 657                 $key = false;
 658                 if ( $this->mOldid && $this->mNewid ) {
 659                         $key = wfMemcKey( 'diff', 'version', MW_DIFF_VERSION,
 660                                 'oldid', $this->mOldid, 'newid', $this->mNewid );
 661                         // Try cache
 662                         if ( !$this->mRefreshCache ) {
 663                                 $difftext = $wgMemc->get( $key );
 664                                 if ( $difftext ) {
 665                                         wfIncrStats( 'diff_cache_hit' );
 666                                         $difftext = $this->localiseLineNumbers( $difftext );
 667                                         $difftext .= "\n<!-- diff cache key $key -->\n";
 668                                         wfProfileOut( __METHOD__ );
 669                                         return $difftext;
 670                                 }
 671                         } // don't try to load but save the result
 672                 }
 673                 $this->mCacheHit = false;
 674
 675                 // Loadtext is permission safe, this just clears out the diff
 676                 if ( !$this->loadText() ) {
 677                         wfProfileOut( __METHOD__ );
 678                         return false;
 679                 }
 680
 681                 $difftext = $this->generateContentDiffBody( $this->mOldContent, $this->mNewContent );
 682
 683                 // Save to cache for 7 days
 684                 if ( !wfRunHooks( 'AbortDiffCache', array( &$this ) ) ) {
 685                         wfIncrStats( 'diff_uncacheable' );
 686                 } elseif ( $key !== false && $difftext !== false ) {
 687                         wfIncrStats( 'diff_cache_miss' );
 688                         $wgMemc->set( $key, $difftext, 7 * 86400 );
 689                 } else {
 690                         wfIncrStats( 'diff_uncacheable' );
 691                 }
 692                 // Replace line numbers with the text in the user's language
 693                 if ( $difftext !== false ) {
 694                         $difftext = $this->localiseLineNumbers( $difftext );
 695                 }
 696                 wfProfileOut( __METHOD__ );
 697                 return $difftext;
 698         }
 699
 700         /**
 701          * Make sure the proper modules are loaded before we try to
 702          * make the diff
 703          */
 704         private function initDiffEngines() {
 705                 global $wgExternalDiffEngine;
 706                 if ( $wgExternalDiffEngine == 'wikidiff' && !function_exists( 'wikidiff_do_diff' ) ) {
 707                         wfProfileIn( __METHOD__ . '-php_wikidiff.so' );
 708                         wfDl( 'php_wikidiff' );
 709                         wfProfileOut( __METHOD__ . '-php_wikidiff.so' );
 710                 }
 711                 elseif ( $wgExternalDiffEngine == 'wikidiff2' && !function_exists( 'wikidiff2_do_diff' ) ) {
 712                         wfProfileIn( __METHOD__ . '-php_wikidiff2.so' );
 713                         wfDl( 'wikidiff2' );
 714                         wfProfileOut( __METHOD__ . '-php_wikidiff2.so' );
 715                 }
 716         }
 717
 718         /**
 719          * Generate a diff, no caching.
 720          *
 721          * This implementation uses generateTextDiffBody() to generate a diff based on the default
 722          * serialization of the given Content objects. This will fail if $old or $new are not
 723          * instances of TextContent.
 724          *
 725          * Subclasses may override this to provide a different rendering for the diff,
 726          * perhaps taking advantage of the content's native form. This is required for all content
 727          * models that are not text based.
 728          *
 729          * @param $old Content: old content
 730          * @param $new Content: new content
 731          *
 732          * @since 1.21
 733          * @throws MWException if $old or $new are not instances of TextContent.
 734          */
 735         function generateContentDiffBody( Content $old, Content $new ) {
 736                 if ( !( $old instanceof TextContent ) ) {
 737                         throw new MWException( "Diff not implemented for " . get_class( $old ) . "; "
 738                                         . "override generateContentDiffBody to fix this." );
 739                 }
 740
 741                 if ( !( $new instanceof TextContent ) ) {
 742                         throw new MWException( "Diff not implemented for " . get_class( $new ) . "; "
 743                                 . "override generateContentDiffBody to fix this." );
 744                 }
 745
 746                 $otext = $old->serialize();
 747                 $ntext = $new->serialize();
 748
 749                 return $this->generateTextDiffBody( $otext, $ntext );
 750         }
 751
 752         /**
 753          * Generate a diff, no caching
 754          *
 755          * @param $otext String: old text, must be already segmented
 756          * @param $ntext String: new text, must be already segmented
 757          * @deprecated since 1.21, use generateContentDiffBody() instead!
 758          */
 759         function generateDiffBody( $otext, $ntext ) {
 760                 ContentHandler::deprecated( __METHOD__, "1.21" );
 761
 762                 return $this->generateTextDiffBody( $otext, $ntext );
 763         }
 764
 765         /**
 766          * Generate a diff, no caching
 767          *
 768          * @todo move this to TextDifferenceEngine, make DifferenceEngine abstract. At some point.
 769          *
 770          * @param $otext String: old text, must be already segmented
 771          * @param $ntext String: new text, must be already segmented
 772          * @return bool|string
 773          */
 774         function generateTextDiffBody( $otext, $ntext ) {
 775                 global $wgExternalDiffEngine, $wgContLang;
 776
 777                 wfProfileIn( __METHOD__ );
 778
 779                 $otext = str_replace( "\r\n", "\n", $otext );
 780                 $ntext = str_replace( "\r\n", "\n", $ntext );
 781
 782                 $this->initDiffEngines();
 783
 784                 if ( $wgExternalDiffEngine == 'wikidiff' && function_exists( 'wikidiff_do_diff' ) ) {
 785                         # For historical reasons, external diff engine expects
 786                         # input text to be HTML-escaped already
 787                         $otext = htmlspecialchars ( $wgContLang->segmentForDiff( $otext ) );
 788                         $ntext = htmlspecialchars ( $wgContLang->segmentForDiff( $ntext ) );
 789                         wfProfileOut( __METHOD__ );
 790                         return $wgContLang->unsegmentForDiff( wikidiff_do_diff( $otext, $ntext, 2 ) ) .
 791                         $this->debug( 'wikidiff1' );
 792                 }
 793
 794                 if ( $wgExternalDiffEngine == 'wikidiff2' && function_exists( 'wikidiff2_do_diff' ) ) {
 795                         # Better external diff engine, the 2 may some day be dropped
 796                         # This one does the escaping and segmenting itself
 797                         wfProfileIn( 'wikidiff2_do_diff' );
 798                         $text = wikidiff2_do_diff( $otext, $ntext, 2 );
 799                         $text .= $this->debug( 'wikidiff2' );
 800                         wfProfileOut( 'wikidiff2_do_diff' );
 801                         wfProfileOut( __METHOD__ );
 802                         return $text;
 803                 }
 804                 if ( $wgExternalDiffEngine != 'wikidiff3' && $wgExternalDiffEngine !== false ) {
 805                         # Diff via the shell
 806                         $tmpDir = wfTempDir();
 807                         $tempName1 = tempnam( $tmpDir, 'diff_' );
 808                         $tempName2 = tempnam( $tmpDir, 'diff_' );
 809
 810                         $tempFile1 = fopen( $tempName1, "w" );
 811                         if ( !$tempFile1 ) {
 812                                 wfProfileOut( __METHOD__ );
 813                                 return false;
 814                         }
 815                         $tempFile2 = fopen( $tempName2, "w" );
 816                         if ( !$tempFile2 ) {
 817                                 wfProfileOut( __METHOD__ );
 818                                 return false;
 819                         }
 820                         fwrite( $tempFile1, $otext );
 821                         fwrite( $tempFile2, $ntext );
 822                         fclose( $tempFile1 );
 823                         fclose( $tempFile2 );
 824                         $cmd = wfEscapeShellArg( $wgExternalDiffEngine, $tempName1, $tempName2 );
 825                         wfProfileIn( __METHOD__ . "-shellexec" );
 826                         $difftext = wfShellExec( $cmd );
 827                         $difftext .= $this->debug( "external $wgExternalDiffEngine" );
 828                         wfProfileOut( __METHOD__ . "-shellexec" );
 829                         unlink( $tempName1 );
 830                         unlink( $tempName2 );
 831                         wfProfileOut( __METHOD__ );
 832                         return $difftext;
 833                 }
 834
 835                 # Native PHP diff
 836                 $ota = explode( "\n", $wgContLang->segmentForDiff( $otext ) );
 837                 $nta = explode( "\n", $wgContLang->segmentForDiff( $ntext ) );
 838                 $diffs = new Diff( $ota, $nta );
 839                 $formatter = new TableDiffFormatter();
 840                 $difftext = $wgContLang->unsegmentForDiff( $formatter->format( $diffs ) ) .
 841                 wfProfileOut( __METHOD__ );
 842                 return $difftext;
 843         }
 844
 845         /**
 846          * Generate a debug comment indicating diff generating time,
 847          * server node, and generator backend.
 848          * @return string
 849          */
 850         protected function debug( $generator = "internal" ) {
 851                 global $wgShowHostnames;
 852                 if ( !$this->enableDebugComment ) {
 853                         return '';
 854                 }
 855                 $data = array( $generator );
 856                 if ( $wgShowHostnames ) {
 857                         $data[] = wfHostname();
 858                 }
 859                 $data[] = wfTimestamp( TS_DB );
 860                 return "<!-- diff generator: " .
 861                 implode( " ",
 862                 array_map(
 863                                         "htmlspecialchars",
 864                 $data ) ) .
 865                         " -->\n";
 866         }
 867
 868         /**
 869          * Replace line numbers with the text in the user's language
 870          * @return mixed
 871          */
 872         function localiseLineNumbers( $text ) {
 873                 return preg_replace_callback( '/<!--LINE (\d+)-->/',
 874                 array( &$this, 'localiseLineNumbersCb' ), $text );
 875         }
 876
 877         function localiseLineNumbersCb( $matches ) {
 878                 if ( $matches[1] === '1' && $this->mReducedLineNumbers ) return '';
 879                 return $this->msg( 'lineno' )->numParams( $matches[1] )->escaped();
 880         }
 881
 882
 883         /**
 884          * If there are revisions between the ones being compared, return a note saying so.
 885          * @return string
 886          */
 887         function getMultiNotice() {
 888                 if ( !is_object( $this->mOldRev ) || !is_object( $this->mNewRev ) ) {
 889                         return '';
 890                 } elseif ( !$this->mOldPage->equals( $this->mNewPage ) ) {
 891                         // Comparing two different pages? Count would be meaningless.
 892                         return '';
 893                 }
 894
 895                 if ( $this->mOldRev->getTimestamp() > $this->mNewRev->getTimestamp() ) {
 896                         $oldRev = $this->mNewRev; // flip
 897                         $newRev = $this->mOldRev; // flip
 898                 } else { // normal case
 899                         $oldRev = $this->mOldRev;
 900                         $newRev = $this->mNewRev;
 901                 }
 902
 903                 $nEdits = $this->mNewPage->countRevisionsBetween( $oldRev, $newRev );
 904                 if ( $nEdits > 0 ) {
 905                         $limit = 100; // use diff-multi-manyusers if too many users
 906                         $numUsers = $this->mNewPage->countAuthorsBetween( $oldRev, $newRev, $limit );
 907                         return self::intermediateEditsMsg( $nEdits, $numUsers, $limit );
 908                 }
 909                 return ''; // nothing
 910         }
 911
 912         /**
 913          * Get a notice about how many intermediate edits and users there are
 914          * @param $numEdits int
 915          * @param $numUsers int
 916          * @param $limit int
 917          * @return string
 918          */
 919         public static function intermediateEditsMsg( $numEdits, $numUsers, $limit ) {
 920                 if ( $numUsers > $limit ) {
 921                         $msg = 'diff-multi-manyusers';
 922                         $numUsers = $limit;
 923                 } else {
 924                         $msg = 'diff-multi';
 925                 }
 926                 return wfMessage( $msg )->numParams( $numEdits, $numUsers )->parse();
 927         }
 928
 929         /**
 930          * Get a header for a specified revision.
 931          *
 932          * @param $rev Revision
 933          * @param $complete String: 'complete' to get the header wrapped depending
 934          *        the visibility of the revision and a link to edit the page.
 935          * @return String HTML fragment
 936          */
 937         protected function getRevisionHeader( Revision $rev, $complete = '' ) {
 938                 $lang = $this->getLanguage();
 939                 $user = $this->getUser();
 940                 $revtimestamp = $rev->getTimestamp();
 941                 $timestamp = $lang->userTimeAndDate( $revtimestamp, $user );
 942                 $dateofrev = $lang->userDate( $revtimestamp, $user );
 943                 $timeofrev = $lang->userTime( $revtimestamp, $user );
 944
 945                 $header = $this->msg(
 946                         $rev->isCurrent() ? 'currentrev-asof' : 'revisionasof',
 947                         $timestamp,
 948                         $dateofrev,
 949                         $timeofrev
 950                 )->escaped();
 951
 952                 if ( $complete !== 'complete' ) {
 953                         return $header;
 954                 }
 955
 956                 $title = $rev->getTitle();
 957
 958                 $header = Linker::linkKnown( $title, $header, array(),
 959                         array( 'oldid' => $rev->getID() ) );
 960
 961                 if ( $rev->userCan( Revision::DELETED_TEXT, $user ) ) {
 962                         $editQuery = array( 'action' => 'edit' );
 963                         if ( !$rev->isCurrent() ) {
 964                                 $editQuery['oldid'] = $rev->getID();
 965                         }
 966
 967                         $msg = $this->msg( $title->quickUserCan( 'edit', $user ) ? 'editold' : 'viewsourceold' )->escaped();
 968                         $header .= ' ' . $this->msg( 'parentheses' )->rawParams(
 969                                 Linker::linkKnown( $title, $msg, array(), $editQuery ) )->plain();
 970                         if ( $rev->isDeleted( Revision::DELETED_TEXT ) ) {
 971                                 $header = Html::rawElement( 'span', array( 'class' => 'history-deleted' ), $header );
 972                         }
 973                 } else {
 974                         $header = Html::rawElement( 'span', array( 'class' => 'history-deleted' ), $header );
 975                 }
 976
 977                 return $header;
 978         }
 979
 980         /**
 981          * Add the header to a diff body
 982          *
 983          * @return string
 984          */
 985         function addHeader( $diff, $otitle, $ntitle, $multi = '', $notice = '' ) {
 986                 // shared.css sets diff in interface language/dir, but the actual content
 987                 // is often in a different language, mostly the page content language/dir
 988                 $tableClass = 'diff diff-contentalign-' . htmlspecialchars( $this->getDiffLang()->alignStart() );
 989                 $header = "<table class='$tableClass'>";
 990
 991                 if ( !$diff && !$otitle ) {
 992                         $header .= "
 993                         <tr style='vertical-align: top;'>
 994                         <td class='diff-ntitle'>{$ntitle}</td>
 995                         </tr>";
 996                         $multiColspan = 1;
 997                 } else {
 998                         if ( $diff ) { // Safari/Chrome show broken output if cols not used
 999                                 $header .= "
1000                                 <col class='diff-marker' />
1001                                 <col class='diff-content' />
1002                                 <col class='diff-marker' />
1003                                 <col class='diff-content' />";
1004                                 $colspan = 2;
1005                                 $multiColspan = 4;
1006                         } else {
1007                                 $colspan = 1;
1008                                 $multiColspan = 2;
1009                         }
1010                         $header .= "
1011                         <tr style='vertical-align: top;'>
1012                         <td colspan='$colspan' class='diff-otitle'>{$otitle}</td>
1013                         <td colspan='$colspan' class='diff-ntitle'>{$ntitle}</td>
1014                         </tr>";
1015                 }
1016
1017                 if ( $multi != '' ) {
1018                         $header .= "<tr><td colspan='{$multiColspan}' style='text-align: center;' class='diff-multi'>{$multi}</td></tr>";
1019                 }
1020                 if ( $notice != '' ) {
1021                         $header .= "<tr><td colspan='{$multiColspan}' style='text-align: center;'>{$notice}</td></tr>";
1022                 }
1023
1024                 return $header . $diff . "</table>";
1025         }
1026
1027         /**
1028          * Use specified text instead of loading from the database
1029          * @deprecated since 1.21, use setContent() instead.
1030          */
1031         function setText( $oldText, $newText ) {
1032                 ContentHandler::deprecated( __METHOD__, "1.21" );
1033
1034                 $oldContent = ContentHandler::makeContent( $oldText, $this->getTitle() );
1035                 $newContent = ContentHandler::makeContent( $newText, $this->getTitle() );
1036
1037                 $this->setContent( $oldContent, $newContent );
1038         }
1039
1040         /**
1041          * Use specified text instead of loading from the database
1042          * @since 1.21
1043          */
1044         function setContent( Content $oldContent, Content $newContent ) {
1045                 $this->mOldContent = $oldContent;
1046                 $this->mNewContent = $newContent;
1047
1048                 $this->mTextLoaded = 2;
1049                 $this->mRevisionsLoaded = true;
1050         }
1051
1052         /**
1053          * Set the language in which the diff text is written
1054          * (Defaults to page content language).
1055          * @since 1.19
1056          */
1057         function setTextLanguage( $lang ) {
1058                 $this->mDiffLang = wfGetLangObj( $lang );
1059         }
1060
1061         /**
1062          * Load revision IDs
1063          */
1064         private function loadRevisionIds() {
1065                 if ( $this->mRevisionsIdsLoaded ) {
1066                         return;
1067                 }
1068
1069                 $this->mRevisionsIdsLoaded = true;
1070
1071                 $old = $this->mOldid;
1072                 $new = $this->mNewid;
1073
1074                 if ( $new === 'prev' ) {
1075                         # Show diff between revision $old and the previous one.
1076                         # Get previous one from DB.
1077                         $this->mNewid = intval( $old );
1078                         $this->mOldid = $this->getTitle()->getPreviousRevisionID( $this->mNewid );
1079                 } elseif ( $new === 'next' ) {
1080                         # Show diff between revision $old and the next one.
1081                         # Get next one from DB.
1082                         $this->mOldid = intval( $old );
1083                         $this->mNewid = $this->getTitle()->getNextRevisionID( $this->mOldid );
1084                         if ( $this->mNewid === false ) {
1085                                 # if no result, NewId points to the newest old revision. The only newer
1086                                 # revision is cur, which is "0".
1087                                 $this->mNewid = 0;
1088                         }
1089                 } else {
1090                         $this->mOldid = intval( $old );
1091                         $this->mNewid = intval( $new );
1092                         wfRunHooks( 'NewDifferenceEngine', array( $this->getTitle(), &$this->mOldid, &$this->mNewid, $old, $new ) );
1093                 }
1094         }
1095
1096         /**
1097          * Load revision metadata for the specified articles. If newid is 0, then compare
1098          * the old article in oldid to the current article; if oldid is 0, then
1099          * compare the current article to the immediately previous one (ignoring the
1100          * value of newid).
1101          *
1102          * If oldid is false, leave the corresponding revision object set
1103          * to false. This is impossible via ordinary user input, and is provided for
1104          * API convenience.
1105          *
1106          * @return bool
1107          */
1108         function loadRevisionData() {
1109                 if ( $this->mRevisionsLoaded ) {
1110                         return true;
1111                 }
1112
1113                 // Whether it succeeds or fails, we don't want to try again
1114                 $this->mRevisionsLoaded = true;
1115
1116                 $this->loadRevisionIds();
1117
1118                 // Load the new revision object
1119                 $this->mNewRev = $this->mNewid
1120                         ? Revision::newFromId( $this->mNewid )
1121                         : Revision::newFromTitle( $this->getTitle(), false, Revision::READ_NORMAL );
1122
1123                 if ( !$this->mNewRev instanceof Revision ) {
1124                         return false;
1125                 }
1126
1127                 // Update the new revision ID in case it was 0 (makes life easier doing UI stuff)
1128                 $this->mNewid = $this->mNewRev->getId();
1129                 $this->mNewPage = $this->mNewRev->getTitle();
1130
1131                 // Load the old revision object
1132                 $this->mOldRev = false;
1133                 if ( $this->mOldid ) {
1134                         $this->mOldRev = Revision::newFromId( $this->mOldid );
1135                 } elseif ( $this->mOldid === 0 ) {
1136                         $rev = $this->mNewRev->getPrevious();
1137                         if ( $rev ) {
1138                                 $this->mOldid = $rev->getId();
1139                                 $this->mOldRev = $rev;
1140                         } else {
1141                                 // No previous revision; mark to show as first-version only.
1142                                 $this->mOldid = false;
1143                                 $this->mOldRev = false;
1144                         }
1145                 } /* elseif ( $this->mOldid === false ) leave mOldRev false; */
1146
1147                 if ( is_null( $this->mOldRev ) ) {
1148                         return false;
1149                 }
1150
1151                 if ( $this->mOldRev ) {
1152                         $this->mOldPage = $this->mOldRev->getTitle();
1153                 }
1154
1155                 return true;
1156         }
1157
1158         /**
1159          * Load the text of the revisions, as well as revision data.
1160          *
1161          * @return bool
1162          */
1163         function loadText() {
1164                 if ( $this->mTextLoaded == 2 ) {
1165                         return true;
1166                 } else {
1167                         // Whether it succeeds or fails, we don't want to try again
1168                         $this->mTextLoaded = 2;
1169                 }
1170
1171                 if ( !$this->loadRevisionData() ) {
1172                         return false;
1173                 }
1174                 if ( $this->mOldRev ) {
1175                         $this->mOldContent = $this->mOldRev->getContent( Revision::FOR_THIS_USER, $this->getUser() );
1176                         if ( $this->mOldContent === null ) {
1177                                 return false;
1178                         }
1179                 }
1180                 if ( $this->mNewRev ) {
1181                         $this->mNewContent = $this->mNewRev->getContent( Revision::FOR_THIS_USER, $this->getUser() );
1182                         if ( $this->mNewContent === null ) {
1183                                 return false;
1184                         }
1185                 }
1186                 return true;
1187         }
1188
1189         /**
1190          * Load the text of the new revision, not the old one
1191          *
1192          * @return bool
1193          */
1194         function loadNewText() {
1195                 if ( $this->mTextLoaded >= 1 ) {
1196                         return true;
1197                 } else {
1198                         $this->mTextLoaded = 1;
1199                 }
1200                 if ( !$this->loadRevisionData() ) {
1201                         return false;
1202                 }
1203                 $this->mNewContent = $this->mNewRev->getContent( Revision::FOR_THIS_USER, $this->getUser() );
1204                 return true;
1205         }
1206 }