includes/diff/DifferenceEngine.php

   1 <?php
   2 /**
   3  * User interface for the difference engine
   4  *
   5  * @file
   6  * @ingroup DifferenceEngine
   7  */
   8
   9 /**
  10  * Constant to indicate diff cache compatibility.
  11  * Bump this when changing the diff formatting in a way that
  12  * fixes important bugs or such to force cached diff views to
  13  * clear.
  14  */
  15 define( 'MW_DIFF_VERSION', '1.11a' );
  16
  17 /**
  18  * @todo document
  19  * @ingroup DifferenceEngine
  20  */
  21 class DifferenceEngine {
  22         /**#@+
  23          * @private
  24          */
  25         var $mOldid, $mNewid;
  26         var $mOldtitle, $mNewtitle, $mPagetitle;
  27         var $mOldtext, $mNewtext;
  28         var $mDiffLang;
  29
  30         /**
  31          * @var Title
  32          */
  33         var $mOldPage, $mNewPage, $mTitle;
  34         var $mRcidMarkPatrolled;
  35
  36         /**
  37          * @var Revision
  38          */
  39         var $mOldRev, $mNewRev;
  40         var $mRevisionsLoaded = false; // Have the revisions been loaded
  41         var $mTextLoaded = 0; // How many text blobs have been loaded, 0, 1 or 2?
  42         var $mCacheHit = false; // Was the diff fetched from cache?
  43
  44         /**
  45          * Set this to true to add debug info to the HTML output.
  46          * Warning: this may cause RSS readers to spuriously mark articles as "new"
  47          * (bug 20601)
  48          */
  49         var $enableDebugComment = false;
  50
  51         // If true, line X is not displayed when X is 1, for example to increase
  52         // readability and conserve space with many small diffs.
  53         protected $mReducedLineNumbers = false;
  54
  55         protected $unhide = false; # show rev_deleted content if allowed
  56         /**#@-*/
  57
  58         /**
  59          * Constructor
  60          * @param $titleObj Title object that the diff is associated with
  61          * @param $old Integer old ID we want to show and diff with.
  62          * @param $new String either 'prev' or 'next'.
  63          * @param $rcid Integer ??? FIXME (default 0)
  64          * @param $refreshCache boolean If set, refreshes the diff cache
  65          * @param $unhide boolean If set, allow viewing deleted revs
  66          */
  67         function __construct( $titleObj = null, $old = 0, $new = 0, $rcid = 0,
  68                 $refreshCache = false, $unhide = false )
  69         {
  70                 if ( $titleObj ) {
  71                         $this->mTitle = $titleObj;
  72                 } else {
  73                         global $wgTitle;
  74                         $this->mTitle = $wgTitle; // @TODO: get rid of this
  75                 }
  76                 wfDebug( "DifferenceEngine old '$old' new '$new' rcid '$rcid'\n" );
  77
  78                 # Default language in which the diff text is written.
  79                 $this->mDiffLang = $this->mTitle->getPageLanguage();
  80
  81                 if ( 'prev' === $new ) {
  82                         # Show diff between revision $old and the previous one.
  83                         # Get previous one from DB.
  84                         $this->mNewid = intval( $old );
  85                         $this->mOldid = $this->mTitle->getPreviousRevisionID( $this->mNewid );
  86                 } elseif ( 'next' === $new ) {
  87                         # Show diff between revision $old and the next one.
  88                         # Get next one from DB.
  89                         $this->mOldid = intval( $old );
  90                         $this->mNewid = $this->mTitle->getNextRevisionID( $this->mOldid );
  91                         if ( false === $this->mNewid ) {
  92                                 # if no result, NewId points to the newest old revision. The only newer
  93                                 # revision is cur, which is "0".
  94                                 $this->mNewid = 0;
  95                         }
  96                 } else {
  97                         $this->mOldid = intval( $old );
  98                         $this->mNewid = intval( $new );
  99                         wfRunHooks( 'NewDifferenceEngine', array( &$titleObj, &$this->mOldid, &$this->mNewid, $old, $new ) );
 100                 }
 101                 $this->mRcidMarkPatrolled = intval( $rcid );  # force it to be an integer
 102                 $this->mRefreshCache = $refreshCache;
 103                 $this->unhide = $unhide;
 104         }
 105
 106         /**
 107          * @param $value bool
 108          */
 109         function setReducedLineNumbers( $value = true ) {
 110                 $this->mReducedLineNumbers = $value;
 111         }
 112
 113         /**
 114          * @return Title
 115          */
 116         function getTitle() {
 117                 return $this->mTitle;
 118         }
 119
 120         /**
 121          * @return bool
 122          */
 123         function wasCacheHit() {
 124                 return $this->mCacheHit;
 125         }
 126
 127         /**
 128          * @return int
 129          */
 130         function getOldid() {
 131                 return $this->mOldid;
 132         }
 133
 134         /**
 135          * @return Bool|int
 136          */
 137         function getNewid() {
 138                 return $this->mNewid;
 139         }
 140
 141         /**
 142          * Look up a special:Undelete link to the given deleted revision id,
 143          * as a workaround for being unable to load deleted diffs in currently.
 144          *
 145          * @param int $id revision ID
 146          * @return mixed URL or false
 147          */
 148         function deletedLink( $id ) {
 149                 global $wgUser;
 150                 if ( $wgUser->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         function showDiffPage( $diffOnly = false ) {
 183                 global $wgUser, $wgOut, $wgUseExternalEditor, $wgUseRCPatrol;
 184                 wfProfileIn( __METHOD__ );
 185
 186                 # Allow frames except in certain special cases
 187                 $wgOut->allowClickjacking();
 188
 189                 # If external diffs are enabled both globally and for the user,
 190                 # we'll use the application/x-external-editor interface to call
 191                 # an external diff tool like kompare, kdiff3, etc.
 192                 if ( $wgUseExternalEditor && $wgUser->getOption( 'externaldiff' ) ) {
 193                         global $wgServer, $wgScript, $wgLang;
 194                         $wgOut->disable();
 195                         header ( "Content-type: application/x-external-editor; charset=UTF-8" );
 196                         $url1 = $this->mTitle->getFullURL( array(
 197                                 'action' => 'raw',
 198                                 'oldid' => $this->mOldid
 199                         ) );
 200                         $url2 = $this->mTitle->getFullURL( array(
 201                                 'action' => 'raw',
 202                                 'oldid' => $this->mNewid
 203                         ) );
 204                         $special = $wgLang->getNsText( NS_SPECIAL );
 205                         $control = <<<CONTROL
 206                         [Process]
 207                         Type=Diff text
 208                         Engine=MediaWiki
 209                         Script={$wgServer}{$wgScript}
 210                         Special namespace={$special}
 211
 212                         [File]
 213                         Extension=wiki
 214                         URL=$url1
 215
 216                         [File 2]
 217                         Extension=wiki
 218                         URL=$url2
 219 CONTROL;
 220                         echo( $control );
 221
 222                         wfProfileOut( __METHOD__ );
 223                         return;
 224                 }
 225
 226                 $wgOut->setArticleFlag( false );
 227                 if ( !$this->loadRevisionData() ) {
 228                         // Sounds like a deleted revision... Let's see what we can do.
 229                         $t = $this->mTitle->getPrefixedText();
 230                         $d = wfMsgExt( 'missingarticle-diff', array( 'escape' ),
 231                                 $this->deletedIdMarker( $this->mOldid ),
 232                                 $this->deletedIdMarker( $this->mNewid ) );
 233                         $wgOut->setPagetitle( wfMsg( 'errorpagetitle' ) );
 234                         $wgOut->addWikiMsg( 'missing-article', "<nowiki>$t</nowiki>", "<span class='plainlinks'>$d</span>" );
 235                         wfProfileOut( __METHOD__ );
 236                         return;
 237                 }
 238
 239                 wfRunHooks( 'DiffViewHeader', array( $this, $this->mOldRev, $this->mNewRev ) );
 240
 241                 if ( $this->mNewRev->isCurrent() ) {
 242                         $wgOut->setArticleFlag( true );
 243                 }
 244
 245                 # mOldid is false if the difference engine is called with a "vague" query for
 246                 # a diff between a version V and its previous version V' AND the version V
 247                 # is the first version of that article. In that case, V' does not exist.
 248                 if ( $this->mOldid === false ) {
 249                         $this->showFirstRevision();
 250                         $this->renderNewRevision();  // should we respect $diffOnly here or not?
 251                         wfProfileOut( __METHOD__ );
 252                         return;
 253                 }
 254
 255                 $oldTitle = $this->mOldPage->getPrefixedText();
 256                 $newTitle = $this->mNewPage->getPrefixedText();
 257                 if ( $oldTitle == $newTitle ) {
 258                         $wgOut->setPageTitle( $newTitle );
 259                 } else {
 260                         $wgOut->setPageTitle( $oldTitle . ', ' . $newTitle );
 261                 }
 262                 if ( $this->mNewPage->equals( $this->mOldPage ) ) {
 263                         $wgOut->setSubtitle( wfMsgExt( 'difference', array( 'parseinline' ) ) );
 264                 } else {
 265                         $wgOut->setSubtitle( wfMsgExt( 'difference-multipage', array( 'parseinline' ) ) );
 266                 }
 267                 $wgOut->setRobotPolicy( 'noindex,nofollow' );
 268
 269                 if ( !$this->mOldPage->userCanRead() || !$this->mNewPage->userCanRead() ) {
 270                         $wgOut->loginToUse();
 271                         $wgOut->output();
 272                         $wgOut->disable();
 273                         wfProfileOut( __METHOD__ );
 274                         return;
 275                 }
 276
 277                 $sk = $wgUser->getSkin();
 278                 if ( method_exists( $sk, 'suppressQuickbar' ) ) {
 279                         $sk->suppressQuickbar();
 280                 }
 281
 282                 // Check if page is editable
 283                 $editable = $this->mNewRev->getTitle()->userCan( 'edit' );
 284                 if ( $editable && $this->mNewRev->isCurrent() && $wgUser->isAllowed( 'rollback' ) ) {
 285                         $wgOut->preventClickjacking();
 286                         $rollback = '&#160;&#160;&#160;' . $sk->generateRollback( $this->mNewRev );
 287                 } else {
 288                         $rollback = '';
 289                 }
 290
 291                 // Prepare a change patrol link, if applicable
 292                 if ( $wgUseRCPatrol && $this->mTitle->userCan( 'patrol' ) ) {
 293                         // If we've been given an explicit change identifier, use it; saves time
 294                         if ( $this->mRcidMarkPatrolled ) {
 295                                 $rcid = $this->mRcidMarkPatrolled;
 296                                 $rc = RecentChange::newFromId( $rcid );
 297                                 // Already patrolled?
 298                                 $rcid = is_object( $rc ) && !$rc->getAttribute( 'rc_patrolled' ) ? $rcid : 0;
 299                         } else {
 300                                 // Look for an unpatrolled change corresponding to this diff
 301                                 $db = wfGetDB( DB_SLAVE );
 302                                 $change = RecentChange::newFromConds(
 303                                         array(
 304                                         // Redundant user,timestamp condition so we can use the existing index
 305                                                 'rc_user_text'  => $this->mNewRev->getRawUserText(),
 306                                                 'rc_timestamp'  => $db->timestamp( $this->mNewRev->getTimestamp() ),
 307                                                 'rc_this_oldid' => $this->mNewid,
 308                                                 'rc_last_oldid' => $this->mOldid,
 309                                                 'rc_patrolled'  => 0
 310                                         ),
 311                                         __METHOD__
 312                                 );
 313                                 if ( $change instanceof RecentChange ) {
 314                                         $rcid = $change->mAttribs['rc_id'];
 315                                         $this->mRcidMarkPatrolled = $rcid;
 316                                 } else {
 317                                         // None found
 318                                         $rcid = 0;
 319                                 }
 320                         }
 321                         // Build the link
 322                         if ( $rcid ) {
 323                                 $wgOut->preventClickjacking();
 324                                 $token = $wgUser->editToken( $rcid );
 325                                 $patrol = ' <span class="patrollink">[' . $sk->link(
 326                                         $this->mTitle,
 327                                         wfMsgHtml( 'markaspatrolleddiff' ),
 328                                         array(),
 329                                         array(
 330                                                 'action' => 'markpatrolled',
 331                                                 'rcid' => $rcid,
 332                                                 'token' => $token,
 333                                         ),
 334                                         array(
 335                                                 'known',
 336                                                 'noclasses'
 337                                         )
 338                                 ) . ']</span>';
 339                         } else {
 340                                 $patrol = '';
 341                         }
 342                 } else {
 343                         $patrol = '';
 344                 }
 345
 346                 # Carry over 'diffonly' param via navigation links
 347                 if ( $diffOnly != $wgUser->getBoolOption( 'diffonly' ) ) {
 348                         $query['diffonly'] = $diffOnly;
 349                 }
 350
 351                 # Make "previous revision link"
 352                 $query['diff'] = 'prev';
 353                 $query['oldid'] = $this->mOldid;
 354                 # Cascade unhide param in links for easy deletion browsing
 355                 if ( $this->unhide ) {
 356                         $query['unhide'] = 1;
 357                 }
 358                 if ( !$this->mOldRev->getPrevious() ) {
 359                         $prevlink = '&#160;';
 360                 } else {
 361                         $prevlink = $sk->link(
 362                                 $this->mTitle,
 363                                 wfMsgHtml( 'previousdiff' ),
 364                                 array(
 365                                         'id' => 'differences-prevlink'
 366                                 ),
 367                                 $query,
 368                                 array(
 369                                         'known',
 370                                         'noclasses'
 371                                 )
 372                         );
 373                 }
 374
 375                 # Make "next revision link"
 376                 $query['diff'] = 'next';
 377                 $query['oldid'] = $this->mNewid;
 378                 # Skip next link on the top revision
 379                 if ( $this->mNewRev->isCurrent() ) {
 380                         $nextlink = '&#160;';
 381                 } else {
 382                         $nextlink = $sk->link(
 383                                 $this->mTitle,
 384                                 wfMsgHtml( 'nextdiff' ),
 385                                 array(
 386                                         'id' => 'differences-nextlink'
 387                                 ),
 388                                 $query,
 389                                 array(
 390                                         'known',
 391                                         'noclasses'
 392                                 )
 393                         );
 394                 }
 395
 396                 $oldminor = '';
 397                 $newminor = '';
 398
 399                 if ( $this->mOldRev->isMinor() ) {
 400                         $oldminor = ChangesList::flag( 'minor' );
 401                 }
 402                 if ( $this->mNewRev->isMinor() ) {
 403                         $newminor = ChangesList::flag( 'minor' );
 404                 }
 405
 406                 # Handle RevisionDelete links...
 407                 $ldel = $this->revisionDeleteLink( $this->mOldRev );
 408                 $rdel = $this->revisionDeleteLink( $this->mNewRev );
 409
 410                 $oldHeader = '<div id="mw-diff-otitle1"><strong>' . $this->mOldtitle . '</strong></div>' .
 411                         '<div id="mw-diff-otitle2">' .
 412                                 $sk->revUserTools( $this->mOldRev, !$this->unhide ) . '</div>' .
 413                         '<div id="mw-diff-otitle3">' . $oldminor .
 414                                 $sk->revComment( $this->mOldRev, !$diffOnly, !$this->unhide ) . $ldel . '</div>' .
 415                         '<div id="mw-diff-otitle4">' . $prevlink . '</div>';
 416                 $newHeader = '<div id="mw-diff-ntitle1"><strong>' . $this->mNewtitle . '</strong></div>' .
 417                         '<div id="mw-diff-ntitle2">' . $sk->revUserTools( $this->mNewRev, !$this->unhide ) .
 418                                 " $rollback</div>" .
 419                         '<div id="mw-diff-ntitle3">' . $newminor .
 420                                 $sk->revComment( $this->mNewRev, !$diffOnly, !$this->unhide ) . $rdel . '</div>' .
 421                         '<div id="mw-diff-ntitle4">' . $nextlink . $patrol . '</div>';
 422
 423                 # Check if this user can see the revisions
 424                 $allowed = $this->mOldRev->userCan( Revision::DELETED_TEXT )
 425                         && $this->mNewRev->userCan( Revision::DELETED_TEXT );
 426                 # Check if one of the revisions is deleted/suppressed
 427                 $deleted = $suppressed = false;
 428                 if ( $this->mOldRev->isDeleted( Revision::DELETED_TEXT ) ) {
 429                         $deleted = true; // old revisions text is hidden
 430                         if ( $this->mOldRev->isDeleted( Revision::DELETED_RESTRICTED ) )
 431                                 $suppressed = true; // also suppressed
 432                 }
 433                 if ( $this->mNewRev->isDeleted( Revision::DELETED_TEXT ) ) {
 434                         $deleted = true; // new revisions text is hidden
 435                         if ( $this->mNewRev->isDeleted( Revision::DELETED_RESTRICTED ) )
 436                                 $suppressed = true; // also suppressed
 437                 }
 438                 # If the diff cannot be shown due to a deleted revision, then output
 439                 # the diff header and links to unhide (if available)...
 440                 if ( $deleted && ( !$this->unhide || !$allowed ) ) {
 441                         $this->showDiffStyle();
 442                         $multi = $this->getMultiNotice();
 443                         $wgOut->addHTML( $this->addHeader( '', $oldHeader, $newHeader, $multi ) );
 444                         if ( !$allowed ) {
 445                                 $msg = $suppressed ? 'rev-suppressed-no-diff' : 'rev-deleted-no-diff';
 446                                 # Give explanation for why revision is not visible
 447                                 $wgOut->wrapWikiMsg( "<div id='mw-$msg' class='mw-warning plainlinks'>\n$1\n</div>\n",
 448                                         array( $msg ) );
 449                         } else {
 450                                 # Give explanation and add a link to view the diff...
 451                                 $link = $this->mTitle->getFullUrl( array(
 452                                         'diff' => $this->mNewid,
 453                                         'oldid' => $this->mOldid,
 454                                         'unhide' => 1
 455                                 ) );
 456                                 $msg = $suppressed ? 'rev-suppressed-unhide-diff' : 'rev-deleted-unhide-diff';
 457                                 $wgOut->wrapWikiMsg( "<div id='mw-$msg' class='mw-warning plainlinks'>\n$1\n</div>\n", array( $msg, $link ) );
 458                         }
 459                 # Otherwise, output a regular diff...
 460                 } else {
 461                         # Add deletion notice if the user is viewing deleted content
 462                         $notice = '';
 463                         if ( $deleted ) {
 464                                 $msg = $suppressed ? 'rev-suppressed-diff-view' : 'rev-deleted-diff-view';
 465                                 $notice = "<div id='mw-$msg' class='mw-warning plainlinks'>\n" . wfMsgExt( $msg, 'parseinline' ) . "</div>\n";
 466                         }
 467                         $this->showDiff( $oldHeader, $newHeader, $notice );
 468                         if ( !$diffOnly ) {
 469                                 $this->renderNewRevision();
 470                         }
 471                 }
 472                 wfProfileOut( __METHOD__ );
 473         }
 474
 475         /**
 476          * @param $rev Revision
 477          * @return String
 478          */
 479         protected function revisionDeleteLink( $rev ) {
 480                 global $wgUser;
 481                 $link = '';
 482                 $canHide = $wgUser->isAllowed( 'deleterevision' );
 483                 // Show del/undel link if:
 484                 // (a) the user can delete revisions, or
 485                 // (b) the user can view deleted revision *and* this one is deleted
 486                 if ( $canHide || ( $rev->getVisibility() && $wgUser->isAllowed( 'deletedhistory' ) ) ) {
 487                         $sk = $wgUser->getSkin();
 488                         if ( !$rev->userCan( Revision::DELETED_RESTRICTED ) ) {
 489                                 $link = $sk->revDeleteLinkDisabled( $canHide ); // revision was hidden from sysops
 490                         } else {
 491                                 $query = array(
 492                                         'type'   => 'revision',
 493                                         'target' => $rev->mTitle->getPrefixedDbkey(),
 494                                         'ids'    => $rev->getId()
 495                                 );
 496                                 $link = $sk->revDeleteLink( $query,
 497                                         $rev->isDeleted( Revision::DELETED_RESTRICTED ), $canHide );
 498                         }
 499                         $link = '&#160;&#160;&#160;' . $link . ' ';
 500                 }
 501                 return $link;
 502         }
 503
 504         /**
 505          * Show the new revision of the page.
 506          */
 507         function renderNewRevision() {
 508                 global $wgOut, $wgUser;
 509                 wfProfileIn( __METHOD__ );
 510                 # Add "current version as of X" title
 511                 $wgOut->addHTML( "<hr class='diff-hr' />
 512                 <h2 class='diff-currentversion-title'>{$this->mPagetitle}</h2>\n" );
 513                 # Page content may be handled by a hooked call instead...
 514                 if ( wfRunHooks( 'ArticleContentOnDiff', array( $this, $wgOut ) ) ) {
 515                         # Use the current version parser cache if applicable
 516                         $pCache = true;
 517                         if ( !$this->mNewRev->isCurrent() ) {
 518                                 $oldEditSectionSetting = $wgOut->parserOptions()->setEditSection( false );
 519                                 $pCache = false;
 520                         }
 521
 522                         $this->loadNewText();
 523                         $wgOut->setRevisionId( $this->mNewRev->getId() );
 524
 525                         if ( $this->mTitle->isCssJsSubpage() || $this->mTitle->isCssOrJsPage() ) {
 526                                 // Stolen from Article::view --AG 2007-10-11
 527                                 // Give hooks a chance to customise the output
 528                                 // @TODO: standardize this crap into one function
 529                                 if ( wfRunHooks( 'ShowRawCssJs', array( $this->mNewtext, $this->mTitle, $wgOut ) ) ) {
 530                                         // Wrap the whole lot in a <pre> and don't parse
 531                                         $m = array();
 532                                         preg_match( '!\.(css|js)$!u', $this->mTitle->getText(), $m );
 533                                         $wgOut->addHTML( "<pre class=\"mw-code mw-{$m[1]}\" dir=\"ltr\">\n" );
 534                                         $wgOut->addHTML( htmlspecialchars( $this->mNewtext ) );
 535                                         $wgOut->addHTML( "\n</pre>\n" );
 536                                 }
 537                         } elseif ( $pCache ) {
 538                                 $article = new Article( $this->mTitle, 0 );
 539                                 $pOutput = ParserCache::singleton()->get( $article, $wgOut->parserOptions() );
 540                                 if( $pOutput ) {
 541                                         $wgOut->addParserOutput( $pOutput );
 542                                 } else {
 543                                         $article->doViewParse();
 544                                 }
 545                         } else {
 546                                 $wgOut->addWikiTextTidy( $this->mNewtext );
 547                         }
 548
 549                         if ( !$this->mNewRev->isCurrent() ) {
 550                                 $wgOut->parserOptions()->setEditSection( $oldEditSectionSetting );
 551                         }
 552                 }
 553                 # Add redundant patrol link on bottom...
 554                 if ( $this->mRcidMarkPatrolled && $this->mTitle->quickUserCan( 'patrol' ) ) {
 555                         $sk = $wgUser->getSkin();
 556                         $token = $wgUser->editToken( $this->mRcidMarkPatrolled );
 557                         $wgOut->preventClickjacking();
 558                         $wgOut->addHTML(
 559                                 "<div class='patrollink'>[" . $sk->link(
 560                                         $this->mTitle,
 561                                         wfMsgHtml( 'markaspatrolleddiff' ),
 562                                         array(),
 563                                         array(
 564                                                 'action'        => 'markpatrolled',
 565                                                 'rcid'          => $this->mRcidMarkPatrolled,
 566                                                 'token'         => $token,
 567                                         )
 568                                 ) . ']</div>'
 569                          );
 570                 }
 571
 572                 wfProfileOut( __METHOD__ );
 573         }
 574
 575         /**
 576          * Show the first revision of an article. Uses normal diff headers in
 577          * contrast to normal "old revision" display style.
 578          */
 579         function showFirstRevision() {
 580                 global $wgOut, $wgUser;
 581                 wfProfileIn( __METHOD__ );
 582
 583                 # Get article text from the DB
 584                 #
 585                 if ( ! $this->loadNewText() ) {
 586                         $t = $this->mTitle->getPrefixedText();
 587                         $d = wfMsgExt( 'missingarticle-diff', array( 'escape' ),
 588                                         $this->deletedIdMarker( $this->mOldid ),
 589                                         $this->deletedIdMarker( $this->mNewid ) );
 590                         $wgOut->setPagetitle( wfMsg( 'errorpagetitle' ) );
 591                         $wgOut->addWikiMsg( 'missing-article', "<nowiki>$t</nowiki>", "<span class='plainlinks'>$d</span>" );
 592                         wfProfileOut( __METHOD__ );
 593                         return;
 594                 }
 595                 if ( $this->mNewRev->isCurrent() ) {
 596                         $wgOut->setArticleFlag( true );
 597                 }
 598
 599                 # Check if user is allowed to look at this page. If not, bail out.
 600                 #
 601                 if ( !$this->mTitle->userCanRead() ) {
 602                         $wgOut->loginToUse();
 603                         $wgOut->output();
 604                         wfProfileOut( __METHOD__ );
 605                         throw new MWException( "Permission Error: you do not have access to view this page" );
 606                 }
 607
 608                 # Prepare the header box
 609                 #
 610                 $sk = $wgUser->getSkin();
 611
 612                 $next = $this->mTitle->getNextRevisionID( $this->mNewid );
 613                 if ( !$next ) {
 614                         $nextlink = '';
 615                 } else {
 616                         $nextlink = '<br />' . $sk->link(
 617                                 $this->mTitle,
 618                                 wfMsgHtml( 'nextdiff' ),
 619                                 array(
 620                                         'id' => 'differences-nextlink'
 621                                 ),
 622                                 array(
 623                                         'diff' => 'next',
 624                                         'oldid' => $this->mNewid,
 625                                 ),
 626                                 array(
 627                                         'known',
 628                                         'noclasses'
 629                                 )
 630                         );
 631                 }
 632                 $header = "<div class=\"firstrevisionheader\" style=\"text-align: center\">" .
 633                         $sk->revUserTools( $this->mNewRev ) . "<br />" . $sk->revComment( $this->mNewRev ) . $nextlink . "</div>\n";
 634
 635                 $wgOut->addHTML( $header );
 636
 637                 $wgOut->setSubtitle( wfMsgExt( 'difference', array( 'parseinline' ) ) );
 638                 $wgOut->setRobotPolicy( 'noindex,nofollow' );
 639
 640                 wfProfileOut( __METHOD__ );
 641         }
 642
 643         /**
 644          * Get the diff text, send it to $wgOut
 645          * Returns false if the diff could not be generated, otherwise returns true
 646          *
 647          * @return bool
 648          */
 649         function showDiff( $otitle, $ntitle, $notice = '' ) {
 650                 global $wgOut;
 651                 $diff = $this->getDiff( $otitle, $ntitle, $notice );
 652                 if ( $diff === false ) {
 653                         $wgOut->addWikiMsg( 'missing-article', "<nowiki>(fixme, bug)</nowiki>", '' );
 654                         return false;
 655                 } else {
 656                         $this->showDiffStyle();
 657                         $wgOut->addHTML( $diff );
 658                         return true;
 659                 }
 660         }
 661
 662         /**
 663          * Add style sheets and supporting JS for diff display.
 664          */
 665         function showDiffStyle() {
 666                 global $wgOut;
 667                 $wgOut->addModuleStyles( 'mediawiki.action.history.diff' );
 668         }
 669
 670         /**
 671          * Get complete diff table, including header
 672          *
 673          * @param $otitle Title: old title
 674          * @param $ntitle Title: new title
 675          * @param $notice String: HTML between diff header and body
 676          * @return mixed
 677          */
 678         function getDiff( $otitle, $ntitle, $notice = '' ) {
 679                 $body = $this->getDiffBody();
 680                 if ( $body === false ) {
 681                         return false;
 682                 } else {
 683                         $multi = $this->getMultiNotice();
 684                         return $this->addHeader( $body, $otitle, $ntitle, $multi, $notice );
 685                 }
 686         }
 687
 688         /**
 689          * Get the diff table body, without header
 690          *
 691          * @return mixed (string/false)
 692          */
 693         public function getDiffBody() {
 694                 global $wgMemc;
 695                 wfProfileIn( __METHOD__ );
 696                 $this->mCacheHit = true;
 697                 // Check if the diff should be hidden from this user
 698                 if ( !$this->loadRevisionData() ) {
 699                         wfProfileOut( __METHOD__ );
 700                         return false;
 701                 } elseif ( $this->mOldRev && !$this->mOldRev->userCan( Revision::DELETED_TEXT ) ) {
 702                         wfProfileOut( __METHOD__ );
 703                         return false;
 704                 } elseif ( $this->mNewRev && !$this->mNewRev->userCan( Revision::DELETED_TEXT ) ) {
 705                         wfProfileOut( __METHOD__ );
 706                         return false;
 707                 }
 708                 // Short-circuit
 709                 if ( $this->mOldRev && $this->mNewRev
 710                         && $this->mOldRev->getID() == $this->mNewRev->getID() )
 711                 {
 712                         wfProfileOut( __METHOD__ );
 713                         return '';
 714                 }
 715                 // Cacheable?
 716                 $key = false;
 717                 if ( $this->mOldid && $this->mNewid ) {
 718                         $key = wfMemcKey( 'diff', 'version', MW_DIFF_VERSION,
 719                                 'oldid', $this->mOldid, 'newid', $this->mNewid );
 720                         // Try cache
 721                         if ( !$this->mRefreshCache ) {
 722                                 $difftext = $wgMemc->get( $key );
 723                                 if ( $difftext ) {
 724                                         wfIncrStats( 'diff_cache_hit' );
 725                                         $difftext = $this->localiseLineNumbers( $difftext );
 726                                         $difftext .= "\n<!-- diff cache key $key -->\n";
 727                                         wfProfileOut( __METHOD__ );
 728                                         return $difftext;
 729                                 }
 730                         } // don't try to load but save the result
 731                 }
 732                 $this->mCacheHit = false;
 733
 734                 // Loadtext is permission safe, this just clears out the diff
 735                 if ( !$this->loadText() ) {
 736                         wfProfileOut( __METHOD__ );
 737                         return false;
 738                 }
 739
 740                 $difftext = $this->generateDiffBody( $this->mOldtext, $this->mNewtext );
 741
 742                 // Save to cache for 7 days
 743                 if ( !wfRunHooks( 'AbortDiffCache', array( &$this ) ) ) {
 744                         wfIncrStats( 'diff_uncacheable' );
 745                 } elseif ( $key !== false && $difftext !== false ) {
 746                         wfIncrStats( 'diff_cache_miss' );
 747                         $wgMemc->set( $key, $difftext, 7 * 86400 );
 748                 } else {
 749                         wfIncrStats( 'diff_uncacheable' );
 750                 }
 751                 // Replace line numbers with the text in the user's language
 752                 if ( $difftext !== false ) {
 753                         $difftext = $this->localiseLineNumbers( $difftext );
 754                 }
 755                 wfProfileOut( __METHOD__ );
 756                 return $difftext;
 757         }
 758
 759         /**
 760          * Make sure the proper modules are loaded before we try to
 761          * make the diff
 762          */
 763         private function initDiffEngines() {
 764                 global $wgExternalDiffEngine;
 765                 if ( $wgExternalDiffEngine == 'wikidiff' && !function_exists( 'wikidiff_do_diff' ) ) {
 766                         wfProfileIn( __METHOD__ . '-php_wikidiff.so' );
 767                         wfDl( 'php_wikidiff' );
 768                         wfProfileOut( __METHOD__ . '-php_wikidiff.so' );
 769                 }
 770                 elseif ( $wgExternalDiffEngine == 'wikidiff2' && !function_exists( 'wikidiff2_do_diff' ) ) {
 771                         wfProfileIn( __METHOD__ . '-php_wikidiff2.so' );
 772                         wfDl( 'wikidiff2' );
 773                         wfProfileOut( __METHOD__ . '-php_wikidiff2.so' );
 774                 }
 775         }
 776
 777         /**
 778          * Generate a diff, no caching
 779          *
 780          * @param $otext String: old text, must be already segmented
 781          * @param $ntext String: new text, must be already segmented
 782          */
 783         function generateDiffBody( $otext, $ntext ) {
 784                 global $wgExternalDiffEngine, $wgContLang;
 785
 786                 wfProfileIn( __METHOD__ );
 787
 788                 $otext = str_replace( "\r\n", "\n", $otext );
 789                 $ntext = str_replace( "\r\n", "\n", $ntext );
 790
 791                 $this->initDiffEngines();
 792
 793                 if ( $wgExternalDiffEngine == 'wikidiff' && function_exists( 'wikidiff_do_diff' ) ) {
 794                         # For historical reasons, external diff engine expects
 795                         # input text to be HTML-escaped already
 796                         $otext = htmlspecialchars ( $wgContLang->segmentForDiff( $otext ) );
 797                         $ntext = htmlspecialchars ( $wgContLang->segmentForDiff( $ntext ) );
 798                         wfProfileOut( __METHOD__ );
 799                         return $wgContLang->unsegmentForDiff( wikidiff_do_diff( $otext, $ntext, 2 ) ) .
 800                         $this->debug( 'wikidiff1' );
 801                 }
 802
 803                 if ( $wgExternalDiffEngine == 'wikidiff2' && function_exists( 'wikidiff2_do_diff' ) ) {
 804                         # Better external diff engine, the 2 may some day be dropped
 805                         # This one does the escaping and segmenting itself
 806                         wfProfileIn( 'wikidiff2_do_diff' );
 807                         $text = wikidiff2_do_diff( $otext, $ntext, 2 );
 808                         $text .= $this->debug( 'wikidiff2' );
 809                         wfProfileOut( 'wikidiff2_do_diff' );
 810                         wfProfileOut( __METHOD__ );
 811                         return $text;
 812                 }
 813                 if ( $wgExternalDiffEngine != 'wikidiff3' && $wgExternalDiffEngine !== false ) {
 814                         # Diff via the shell
 815                         global $wgTmpDirectory;
 816                         $tempName1 = tempnam( $wgTmpDirectory, 'diff_' );
 817                         $tempName2 = tempnam( $wgTmpDirectory, 'diff_' );
 818
 819                         $tempFile1 = fopen( $tempName1, "w" );
 820                         if ( !$tempFile1 ) {
 821                                 wfProfileOut( __METHOD__ );
 822                                 return false;
 823                         }
 824                         $tempFile2 = fopen( $tempName2, "w" );
 825                         if ( !$tempFile2 ) {
 826                                 wfProfileOut( __METHOD__ );
 827                                 return false;
 828                         }
 829                         fwrite( $tempFile1, $otext );
 830                         fwrite( $tempFile2, $ntext );
 831                         fclose( $tempFile1 );
 832                         fclose( $tempFile2 );
 833                         $cmd = wfEscapeShellArg( $wgExternalDiffEngine, $tempName1, $tempName2 );
 834                         wfProfileIn( __METHOD__ . "-shellexec" );
 835                         $difftext = wfShellExec( $cmd );
 836                         $difftext .= $this->debug( "external $wgExternalDiffEngine" );
 837                         wfProfileOut( __METHOD__ . "-shellexec" );
 838                         unlink( $tempName1 );
 839                         unlink( $tempName2 );
 840                         wfProfileOut( __METHOD__ );
 841                         return $difftext;
 842                 }
 843
 844                 # Native PHP diff
 845                 $ota = explode( "\n", $wgContLang->segmentForDiff( $otext ) );
 846                 $nta = explode( "\n", $wgContLang->segmentForDiff( $ntext ) );
 847                 $diffs = new Diff( $ota, $nta );
 848                 $formatter = new TableDiffFormatter();
 849                 $difftext = $wgContLang->unsegmentForDiff( $formatter->format( $diffs ) ) .
 850                 wfProfileOut( __METHOD__ );
 851                 return $difftext;
 852         }
 853
 854         /**
 855          * Generate a debug comment indicating diff generating time,
 856          * server node, and generator backend.
 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          */
 879         function localiseLineNumbers( $text ) {
 880                 return preg_replace_callback( '/<!--LINE (\d+)-->/',
 881                 array( &$this, 'localiseLineNumbersCb' ), $text );
 882         }
 883
 884         function localiseLineNumbersCb( $matches ) {
 885                 global $wgLang;
 886                 if ( $matches[1] === '1' && $this->mReducedLineNumbers ) return '';
 887                 return wfMsgExt( 'lineno', 'escape', $wgLang->formatNum( $matches[1] ) );
 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->mTitle->countRevisionsBetween( $oldRev, $newRev );
 912                 if ( $nEdits > 0 ) {
 913                         $limit = 100; // use diff-multi-manyusers if too many users
 914                         $numUsers = $this->mTitle->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                 global $wgLang;
 929                 if ( $numUsers > $limit ) {
 930                         $msg = 'diff-multi-manyusers';
 931                         $numUsers = $limit;
 932                 } else {
 933                         $msg = 'diff-multi';
 934                 }
 935                 return wfMsgExt( $msg, 'parseinline',
 936                         $wgLang->formatnum( $numEdits ), $wgLang->formatnum( $numUsers ) );
 937         }
 938
 939         /**
 940          * Add the header to a diff body
 941          *
 942          * @return string
 943          */
 944         function addHeader( $diff, $otitle, $ntitle, $multi = '', $notice = '' ) {
 945                 // shared.css sets diff in interface language/dir, but the actual content
 946                 // is often in a different language, mostly the page content language/dir
 947                 $tableClass = 'diff diff-contentalign-' . htmlspecialchars( $this->mDiffLang->alignStart() );
 948                 $header = "<table class='$tableClass'>";
 949                 if ( $diff ) { // Safari/Chrome show broken output if cols not used
 950                         $header .= "
 951                         <col class='diff-marker' />
 952                         <col class='diff-content' />
 953                         <col class='diff-marker' />
 954                         <col class='diff-content' />";
 955                         $colspan = 2;
 956                         $multiColspan = 4;
 957                 } else {
 958                         $colspan = 1;
 959                         $multiColspan = 2;
 960                 }
 961                 $header .= "
 962                 <tr valign='top'>
 963                 <td colspan='$colspan' class='diff-otitle'>{$otitle}</td>
 964                 <td colspan='$colspan' class='diff-ntitle'>{$ntitle}</td>
 965                 </tr>";
 966
 967                 if ( $multi != '' ) {
 968                         $header .= "<tr><td colspan='{$multiColspan}' align='center' class='diff-multi'>{$multi}</td></tr>";
 969                 }
 970                 if ( $notice != '' ) {
 971                         $header .= "<tr><td colspan='{$multiColspan}' align='center'>{$notice}</td></tr>";
 972                 }
 973
 974                 return $header . $diff . "</table>";
 975         }
 976
 977         /**
 978          * Use specified text instead of loading from the database
 979          */
 980         function setText( $oldText, $newText ) {
 981                 $this->mOldtext = $oldText;
 982                 $this->mNewtext = $newText;
 983                 $this->mTextLoaded = 2;
 984                 $this->mRevisionsLoaded = true;
 985         }
 986
 987         /**
 988          * Set the language in which the diff text is written
 989          * (Defaults to page content language).
 990          * @since 1.19
 991          */
 992         function setDiffLang( $lang ) {
 993                 $this->mDiffLang = wfGetLangObj( $lang );
 994         }
 995
 996         /**
 997          * Load revision metadata for the specified articles. If newid is 0, then compare
 998          * the old article in oldid to the current article; if oldid is 0, then
 999          * compare the current article to the immediately previous one (ignoring the
1000          * value of newid).
1001          *
1002          * If oldid is false, leave the corresponding revision object set
1003          * to false. This is impossible via ordinary user input, and is provided for
1004          * API convenience.
1005          *
1006          * @return bool
1007          */
1008         function loadRevisionData() {
1009                 global $wgLang, $wgUser;
1010                 if ( $this->mRevisionsLoaded ) {
1011                         return true;
1012                 } else {
1013                         // Whether it succeeds or fails, we don't want to try again
1014                         $this->mRevisionsLoaded = true;
1015                 }
1016
1017                 // Load the new revision object
1018                 $this->mNewRev = $this->mNewid
1019                         ? Revision::newFromId( $this->mNewid )
1020                         : Revision::newFromTitle( $this->mTitle );
1021                 if ( !$this->mNewRev instanceof Revision ) {
1022                         return false;
1023                 }
1024
1025                 // Update the new revision ID in case it was 0 (makes life easier doing UI stuff)
1026                 $this->mNewid = $this->mNewRev->getId();
1027
1028                 // Check if page is editable
1029                 $editable = $this->mNewRev->getTitle()->userCan( 'edit' );
1030
1031                 // Set assorted variables
1032                 $timestamp = $wgLang->timeanddate( $this->mNewRev->getTimestamp(), true );
1033                 $dateofrev = $wgLang->date( $this->mNewRev->getTimestamp(), true );
1034                 $timeofrev = $wgLang->time( $this->mNewRev->getTimestamp(), true );
1035                 $this->mNewPage = $this->mNewRev->getTitle();
1036                 if ( $this->mNewRev->isCurrent() ) {
1037                         $newLink = $this->mNewPage->escapeLocalUrl( array(
1038                                 'oldid' => $this->mNewid
1039                         ) );
1040                         $this->mPagetitle = htmlspecialchars( wfMsg(
1041                                 'currentrev-asof',
1042                                 $timestamp,
1043                                 $dateofrev,
1044                                 $timeofrev
1045                         ) );
1046                         $newEdit = $this->mNewPage->escapeLocalUrl( array(
1047                                 'action' => 'edit'
1048                         ) );
1049
1050                         $this->mNewtitle = "<a href='$newLink'>{$this->mPagetitle}</a>";
1051                         $this->mNewtitle .= " (<a href='$newEdit'>" . wfMsgHtml( $editable ? 'editold' : 'viewsourceold' ) . "</a>)";
1052                 } else {
1053                         $newLink = $this->mNewPage->escapeLocalUrl( array(
1054                                 'oldid' => $this->mNewid
1055                         ) );
1056                         $newEdit = $this->mNewPage->escapeLocalUrl( array(
1057                                 'action' => 'edit',
1058                                 'oldid' => $this->mNewid
1059                         ) );
1060                         $this->mPagetitle = htmlspecialchars( wfMsg(
1061                                 'revisionasof',
1062                                 $timestamp,
1063                                 $dateofrev,
1064                                 $timeofrev
1065                         ) );
1066
1067                         $this->mNewtitle = "<a href='$newLink'>{$this->mPagetitle}</a>";
1068                         $this->mNewtitle .= " (<a href='$newEdit'>" . wfMsgHtml( $editable ? 'editold' : 'viewsourceold' ) . "</a>)";
1069                 }
1070                 if ( !$this->mNewRev->userCan( Revision::DELETED_TEXT ) ) {
1071                         $this->mNewtitle = "<span class='history-deleted'>{$this->mPagetitle}</span>";
1072                 } elseif ( $this->mNewRev->isDeleted( Revision::DELETED_TEXT ) ) {
1073                         $this->mNewtitle = "<span class='history-deleted'>{$this->mNewtitle}</span>";
1074                 }
1075
1076                 // Load the old revision object
1077                 $this->mOldRev = false;
1078                 if ( $this->mOldid ) {
1079                         $this->mOldRev = Revision::newFromId( $this->mOldid );
1080                 } elseif ( $this->mOldid === 0 ) {
1081                         $rev = $this->mNewRev->getPrevious();
1082                         if ( $rev ) {
1083                                 $this->mOldid = $rev->getId();
1084                                 $this->mOldRev = $rev;
1085                         } else {
1086                                 // No previous revision; mark to show as first-version only.
1087                                 $this->mOldid = false;
1088                                 $this->mOldRev = false;
1089                         }
1090                 } /* elseif ( $this->mOldid === false ) leave mOldRev false; */
1091
1092                 if ( is_null( $this->mOldRev ) ) {
1093                         return false;
1094                 }
1095
1096                 if ( $this->mOldRev ) {
1097                         $this->mOldPage = $this->mOldRev->getTitle();
1098
1099                         $t = $wgLang->timeanddate( $this->mOldRev->getTimestamp(), true );
1100                         $dateofrev = $wgLang->date( $this->mOldRev->getTimestamp(), true );
1101                         $timeofrev = $wgLang->time( $this->mOldRev->getTimestamp(), true );
1102                         $oldLink = $this->mOldPage->escapeLocalUrl( array(
1103                                 'oldid' => $this->mOldid
1104                         ) );
1105                         $oldEdit = $this->mOldPage->escapeLocalUrl( array(
1106                                 'action' => 'edit',
1107                                 'oldid' => $this->mOldid
1108                         ) );
1109                         $this->mOldPagetitle = htmlspecialchars( wfMsg( 'revisionasof', $t, $dateofrev, $timeofrev ) );
1110
1111                         $this->mOldtitle = "<a href='$oldLink'>{$this->mOldPagetitle}</a>"
1112                         . " (<a href='$oldEdit'>" . wfMsgHtml( $editable ? 'editold' : 'viewsourceold' ) . "</a>)";
1113                         // Add an "undo" link
1114                         if ( $editable && !$this->mOldRev->isDeleted( Revision::DELETED_TEXT ) && !$this->mNewRev->isDeleted( Revision::DELETED_TEXT ) ) {
1115                                 $undoLink = Html::element( 'a', array(
1116                                         'href' => $this->mNewPage->getLocalUrl( array(
1117                                                 'action' => 'edit',
1118                                                 'undoafter' => $this->mOldid,
1119                                                 'undo' => $this->mNewid ) ),
1120                                         'title' => $wgUser->getSkin()->titleAttrib( 'undo' )
1121                                 ), wfMsg( 'editundo' ) );
1122                                 $this->mNewtitle .= ' (' . $undoLink . ')';
1123                         }
1124
1125                         if ( !$this->mOldRev->userCan( Revision::DELETED_TEXT ) ) {
1126                                 $this->mOldtitle = '<span class="history-deleted">' . $this->mOldPagetitle . '</span>';
1127                         } elseif ( $this->mOldRev->isDeleted( Revision::DELETED_TEXT ) ) {
1128                                 $this->mOldtitle = '<span class="history-deleted">' . $this->mOldtitle . '</span>';
1129                         }
1130                 }
1131
1132                 return true;
1133         }
1134
1135         /**
1136          * Load the text of the revisions, as well as revision data.
1137          *
1138          * @return bool
1139          */
1140         function loadText() {
1141                 if ( $this->mTextLoaded == 2 ) {
1142                         return true;
1143                 } else {
1144                         // Whether it succeeds or fails, we don't want to try again
1145                         $this->mTextLoaded = 2;
1146                 }
1147
1148                 if ( !$this->loadRevisionData() ) {
1149                         return false;
1150                 }
1151                 if ( $this->mOldRev ) {
1152                         $this->mOldtext = $this->mOldRev->getText( Revision::FOR_THIS_USER );
1153                         if ( $this->mOldtext === false ) {
1154                                 return false;
1155                         }
1156                 }
1157                 if ( $this->mNewRev ) {
1158                         $this->mNewtext = $this->mNewRev->getText( Revision::FOR_THIS_USER );
1159                         if ( $this->mNewtext === false ) {
1160                                 return false;
1161                         }
1162                 }
1163                 return true;
1164         }
1165
1166         /**
1167          * Load the text of the new revision, not the old one
1168          *
1169          * @return bool
1170          */
1171         function loadNewText() {
1172                 if ( $this->mTextLoaded >= 1 ) {
1173                         return true;
1174                 } else {
1175                         $this->mTextLoaded = 1;
1176                 }
1177                 if ( !$this->loadRevisionData() ) {
1178                         return false;
1179                 }
1180                 $this->mNewtext = $this->mNewRev->getText( Revision::FOR_THIS_USER );
1181                 return true;
1182         }
1183 }