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
  29         /**
  30          * @var Title
  31          */
  32         var $mOldPage, $mNewPage, $mTitle;
  33         var $mRcidMarkPatrolled;
  34
  35         /**
  36          * @var Revision
  37          */
  38         var $mOldRev, $mNewRev;
  39         var $mRevisionsLoaded = false; // Have the revisions been loaded
  40         var $mTextLoaded = 0; // How many text blobs have been loaded, 0, 1 or 2?
  41         var $mCacheHit = false; // Was the diff fetched from cache?
  42
  43         /**
  44          * Set this to true to add debug info to the HTML output.
  45          * Warning: this may cause RSS readers to spuriously mark articles as "new"
  46          * (bug 20601)
  47          */
  48         var $enableDebugComment = false;
  49
  50         // If true, line X is not displayed when X is 1, for example to increase
  51         // readability and conserve space with many small diffs.
  52         protected $mReducedLineNumbers = false;
  53
  54         protected $unhide = false; # show rev_deleted content if allowed
  55         /**#@-*/
  56
  57         /**
  58          * Constructor
  59          * @param $titleObj Title object that the diff is associated with
  60          * @param $old Integer old ID we want to show and diff with.
  61          * @param $new String either 'prev' or 'next'.
  62          * @param $rcid Integer ??? FIXME (default 0)
  63          * @param $refreshCache boolean If set, refreshes the diff cache
  64          * @param $unhide boolean If set, allow viewing deleted revs
  65          */
  66         function __construct( $titleObj = null, $old = 0, $new = 0, $rcid = 0,
  67                 $refreshCache = false, $unhide = false )
  68         {
  69                 if ( $titleObj ) {
  70                         $this->mTitle = $titleObj;
  71                 } else {
  72                         global $wgTitle;
  73                         $this->mTitle = $wgTitle; // @TODO: get rid of this
  74                 }
  75                 wfDebug( "DifferenceEngine old '$old' new '$new' rcid '$rcid'\n" );
  76
  77                 if ( 'prev' === $new ) {
  78                         # Show diff between revision $old and the previous one.
  79                         # Get previous one from DB.
  80                         $this->mNewid = intval( $old );
  81                         $this->mOldid = $this->mTitle->getPreviousRevisionID( $this->mNewid );
  82                 } elseif ( 'next' === $new ) {
  83                         # Show diff between revision $old and the next one.
  84                         # Get next one from DB.
  85                         $this->mOldid = intval( $old );
  86                         $this->mNewid = $this->mTitle->getNextRevisionID( $this->mOldid );
  87                         if ( false === $this->mNewid ) {
  88                                 # if no result, NewId points to the newest old revision. The only newer
  89                                 # revision is cur, which is "0".
  90                                 $this->mNewid = 0;
  91                         }
  92                 } else {
  93                         $this->mOldid = intval( $old );
  94                         $this->mNewid = intval( $new );
  95                         wfRunHooks( 'NewDifferenceEngine', array( &$titleObj, &$this->mOldid, &$this->mNewid, $old, $new ) );
  96                 }
  97                 $this->mRcidMarkPatrolled = intval( $rcid );  # force it to be an integer
  98                 $this->mRefreshCache = $refreshCache;
  99                 $this->unhide = $unhide;
 100         }
 101
 102         /**
 103          * @param $value bool
 104          */
 105         function setReducedLineNumbers( $value = true ) {
 106                 $this->mReducedLineNumbers = $value;
 107         }
 108
 109         /**
 110          * @return Title
 111          */
 112         function getTitle() {
 113                 return $this->mTitle;
 114         }
 115
 116         /**
 117          * @return bool
 118          */
 119         function wasCacheHit() {
 120                 return $this->mCacheHit;
 121         }
 122
 123         /**
 124          * @return int
 125          */
 126         function getOldid() {
 127                 return $this->mOldid;
 128         }
 129
 130         /**
 131          * @return Bool|int
 132          */
 133         function getNewid() {
 134                 return $this->mNewid;
 135         }
 136
 137         /**
 138          * Look up a special:Undelete link to the given deleted revision id,
 139          * as a workaround for being unable to load deleted diffs in currently.
 140          *
 141          * @param int $id revision ID
 142          * @return mixed URL or false
 143          */
 144         function deletedLink( $id ) {
 145                 global $wgUser;
 146                 if ( $wgUser->isAllowed( 'deletedhistory' ) ) {
 147                         $dbr = wfGetDB( DB_SLAVE );
 148                         $row = $dbr->selectRow('archive', '*',
 149                                 array( 'ar_rev_id' => $id ),
 150                                 __METHOD__ );
 151                         if ( $row ) {
 152                                 $rev = Revision::newFromArchiveRow( $row );
 153                                 $title = Title::makeTitleSafe( $row->ar_namespace, $row->ar_title );
 154                                 return SpecialPage::getTitleFor( 'Undelete' )->getFullURL( array(
 155                                         'target' => $title->getPrefixedText(),
 156                                         'timestamp' => $rev->getTimestamp()
 157                                 ));
 158                         }
 159                 }
 160                 return false;
 161         }
 162
 163         /**
 164          * Build a wikitext link toward a deleted revision, if viewable.
 165          *
 166          * @param int $id revision ID
 167          * @return string wikitext fragment
 168          */
 169         function deletedIdMarker( $id ) {
 170                 $link = $this->deletedLink( $id );
 171                 if ( $link ) {
 172                         return "[$link $id]";
 173                 } else {
 174                         return $id;
 175                 }
 176         }
 177
 178         function showDiffPage( $diffOnly = false ) {
 179                 global $wgUser, $wgOut, $wgUseExternalEditor, $wgUseRCPatrol;
 180                 wfProfileIn( __METHOD__ );
 181
 182                 # Allow frames except in certain special cases
 183                 $wgOut->allowClickjacking();
 184
 185                 # If external diffs are enabled both globally and for the user,
 186                 # we'll use the application/x-external-editor interface to call
 187                 # an external diff tool like kompare, kdiff3, etc.
 188                 if ( $wgUseExternalEditor && $wgUser->getOption( 'externaldiff' ) ) {
 189                         global $wgServer, $wgScript, $wgLang;
 190                         $wgOut->disable();
 191                         header ( "Content-type: application/x-external-editor; charset=UTF-8" );
 192                         $url1 = $this->mTitle->getFullURL( array(
 193                                 'action' => 'raw',
 194                                 'oldid' => $this->mOldid
 195                         ) );
 196                         $url2 = $this->mTitle->getFullURL( array(
 197                                 'action' => 'raw',
 198                                 'oldid' => $this->mNewid
 199                         ) );
 200                         $special = $wgLang->getNsText( NS_SPECIAL );
 201                         $control = <<<CONTROL
 202                         [Process]
 203                         Type=Diff text
 204                         Engine=MediaWiki
 205                         Script={$wgServer}{$wgScript}
 206                         Special namespace={$special}
 207
 208                         [File]
 209                         Extension=wiki
 210                         URL=$url1
 211
 212                         [File 2]
 213                         Extension=wiki
 214                         URL=$url2
 215 CONTROL;
 216                         echo( $control );
 217
 218                         wfProfileOut( __METHOD__ );
 219                         return;
 220                 }
 221
 222                 $wgOut->setArticleFlag( false );
 223                 if ( !$this->loadRevisionData() ) {
 224                         // Sounds like a deleted revision... Let's see what we can do.
 225                         $deletedLink = $this->deletedLink( $this->mNewid );
 226
 227                         $t = $this->mTitle->getPrefixedText();
 228                         $d = wfMsgExt( 'missingarticle-diff', array( 'escape' ),
 229                                         $this->deletedIdMarker( $this->mOldid ),
 230                                         $this->deletedIdMarker( $this->mNewid ) );
 231                         $wgOut->setPagetitle( wfMsg( 'errorpagetitle' ) );
 232                         $wgOut->addWikiMsg( 'missing-article', "<nowiki>$t</nowiki>", "<span class='plainlinks'>$d</span>" );
 233                         wfProfileOut( __METHOD__ );
 234                         return;
 235                 }
 236
 237                 wfRunHooks( 'DiffViewHeader', array( $this, $this->mOldRev, $this->mNewRev ) );
 238
 239                 if ( $this->mNewRev->isCurrent() ) {
 240                         $wgOut->setArticleFlag( true );
 241                 }
 242
 243                 # mOldid is false if the difference engine is called with a "vague" query for
 244                 # a diff between a version V and its previous version V' AND the version V
 245                 # is the first version of that article. In that case, V' does not exist.
 246                 if ( $this->mOldid === false ) {
 247                         $this->showFirstRevision();
 248                         $this->renderNewRevision();  // should we respect $diffOnly here or not?
 249                         wfProfileOut( __METHOD__ );
 250                         return;
 251                 }
 252
 253                 $oldTitle = $this->mOldPage->getPrefixedText();
 254                 $newTitle = $this->mNewPage->getPrefixedText();
 255                 if ( $oldTitle == $newTitle ) {
 256                         $wgOut->setPageTitle( $newTitle );
 257                 } else {
 258                         $wgOut->setPageTitle( $oldTitle . ', ' . $newTitle );
 259                 }
 260                 if ( $this->mNewPage->equals( $this->mOldPage ) ) {
 261                         $wgOut->setSubtitle( wfMsgExt( 'difference', array( 'parseinline' ) ) );
 262                 } else {
 263                         $wgOut->setSubtitle( wfMsgExt( 'difference-multipage', array( 'parseinline' ) ) );
 264                 }
 265                 $wgOut->setRobotPolicy( 'noindex,nofollow' );
 266
 267                 if ( !$this->mOldPage->userCanRead() || !$this->mNewPage->userCanRead() ) {
 268                         $wgOut->loginToUse();
 269                         $wgOut->output();
 270                         $wgOut->disable();
 271                         wfProfileOut( __METHOD__ );
 272                         return;
 273                 }
 274
 275                 $sk = $wgUser->getSkin();
 276                 if ( method_exists( $sk, 'suppressQuickbar' ) ) {
 277                         $sk->suppressQuickbar();
 278                 }
 279
 280                 // Check if page is editable
 281                 $editable = $this->mNewRev->getTitle()->userCan( 'edit' );
 282                 if ( $editable && $this->mNewRev->isCurrent() && $wgUser->isAllowed( 'rollback' ) ) {
 283                         $wgOut->preventClickjacking();
 284                         $rollback = '&#160;&#160;&#160;' . $sk->generateRollback( $this->mNewRev );
 285                 } else {
 286                         $rollback = '';
 287                 }
 288
 289                 // Prepare a change patrol link, if applicable
 290                 if ( $wgUseRCPatrol && $this->mTitle->userCan( 'patrol' ) ) {
 291                         // If we've been given an explicit change identifier, use it; saves time
 292                         if ( $this->mRcidMarkPatrolled ) {
 293                                 $rcid = $this->mRcidMarkPatrolled;
 294                                 $rc = RecentChange::newFromId( $rcid );
 295                                 // Already patrolled?
 296                                 $rcid = is_object( $rc ) && !$rc->getAttribute( 'rc_patrolled' ) ? $rcid : 0;
 297                         } else {
 298                                 // Look for an unpatrolled change corresponding to this diff
 299                                 $db = wfGetDB( DB_SLAVE );
 300                                 $change = RecentChange::newFromConds(
 301                                         array(
 302                                         // Redundant user,timestamp condition so we can use the existing index
 303                                                 'rc_user_text'  => $this->mNewRev->getRawUserText(),
 304                                                 'rc_timestamp'  => $db->timestamp( $this->mNewRev->getTimestamp() ),
 305                                                 'rc_this_oldid' => $this->mNewid,
 306                                                 'rc_last_oldid' => $this->mOldid,
 307                                                 'rc_patrolled'  => 0
 308                                         ),
 309                                         __METHOD__
 310                                 );
 311                                 if ( $change instanceof RecentChange ) {
 312                                         $rcid = $change->mAttribs['rc_id'];
 313                                         $this->mRcidMarkPatrolled = $rcid;
 314                                 } else {
 315                                         // None found
 316                                         $rcid = 0;
 317                                 }
 318                         }
 319                         // Build the link
 320                         if ( $rcid ) {
 321                                 $wgOut->preventClickjacking();
 322                                 $token = $wgUser->editToken( $rcid );
 323                                 $patrol = ' <span class="patrollink">[' . $sk->link(
 324                                         $this->mTitle,
 325                                         wfMsgHtml( 'markaspatrolleddiff' ),
 326                                         array(),
 327                                         array(
 328                                                 'action' => 'markpatrolled',
 329                                                 'rcid' => $rcid,
 330                                                 'token' => $token,
 331                                         ),
 332                                         array(
 333                                                 'known',
 334                                                 'noclasses'
 335                                         )
 336                                 ) . ']</span>';
 337                         } else {
 338                                 $patrol = '';
 339                         }
 340                 } else {
 341                         $patrol = '';
 342                 }
 343
 344                 # Carry over 'diffonly' param via navigation links
 345                 if ( $diffOnly != $wgUser->getBoolOption( 'diffonly' ) ) {
 346                         $query['diffonly'] = $diffOnly;
 347                 }
 348
 349                 # Make "previous revision link"
 350                 $query['diff'] = 'prev';
 351                 $query['oldid'] = $this->mOldid;
 352                 # Cascade unhide param in links for easy deletion browsing
 353                 if ( $this->unhide ) {
 354                         $query['unhide'] = 1;
 355                 }
 356                 if ( !$this->mOldRev->getPrevious() ) {
 357                         $prevlink = '&#160;';
 358                 } else {
 359                         $prevlink = $sk->link(
 360                                 $this->mTitle,
 361                                 wfMsgHtml( 'previousdiff' ),
 362                                 array(
 363                                         'id' => 'differences-prevlink'
 364                                 ),
 365                                 $query,
 366                                 array(
 367                                         'known',
 368                                         'noclasses'
 369                                 )
 370                         );
 371                 }
 372
 373                 # Make "next revision link"
 374                 $query['diff'] = 'next';
 375                 $query['oldid'] = $this->mNewid;
 376                 # Skip next link on the top revision
 377                 if ( $this->mNewRev->isCurrent() ) {
 378                         $nextlink = '&#160;';
 379                 } else {
 380                         $nextlink = $sk->link(
 381                                 $this->mTitle,
 382                                 wfMsgHtml( 'nextdiff' ),
 383                                 array(
 384                                         'id' => 'differences-nextlink'
 385                                 ),
 386                                 $query,
 387                                 array(
 388                                         'known',
 389                                         'noclasses'
 390                                 )
 391                         );
 392                 }
 393
 394                 $oldminor = '';
 395                 $newminor = '';
 396
 397                 if ( $this->mOldRev->isMinor() ) {
 398                         $oldminor = ChangesList::flag( 'minor' );
 399                 }
 400                 if ( $this->mNewRev->isMinor() ) {
 401                         $newminor = ChangesList::flag( 'minor' );
 402                 }
 403
 404                 # Handle RevisionDelete links...
 405                 $ldel = $this->revisionDeleteLink( $this->mOldRev );
 406                 $rdel = $this->revisionDeleteLink( $this->mNewRev );
 407
 408                 $oldHeader = '<div id="mw-diff-otitle1"><strong>' . $this->mOldtitle . '</strong></div>' .
 409                         '<div id="mw-diff-otitle2">' .
 410                                 $sk->revUserTools( $this->mOldRev, !$this->unhide ) . '</div>' .
 411                         '<div id="mw-diff-otitle3">' . $oldminor .
 412                                 $sk->revComment( $this->mOldRev, !$diffOnly, !$this->unhide ) . $ldel . '</div>' .
 413                         '<div id="mw-diff-otitle4">' . $prevlink . '</div>';
 414                 $newHeader = '<div id="mw-diff-ntitle1"><strong>' . $this->mNewtitle . '</strong></div>' .
 415                         '<div id="mw-diff-ntitle2">' . $sk->revUserTools( $this->mNewRev, !$this->unhide ) .
 416                                 " $rollback</div>" .
 417                         '<div id="mw-diff-ntitle3">' . $newminor .
 418                                 $sk->revComment( $this->mNewRev, !$diffOnly, !$this->unhide ) . $rdel . '</div>' .
 419                         '<div id="mw-diff-ntitle4">' . $nextlink . $patrol . '</div>';
 420
 421                 # Check if this user can see the revisions
 422                 $allowed = $this->mOldRev->userCan( Revision::DELETED_TEXT )
 423                         && $this->mNewRev->userCan( Revision::DELETED_TEXT );
 424                 # Check if one of the revisions is deleted/suppressed
 425                 $deleted = $suppressed = false;
 426                 if ( $this->mOldRev->isDeleted( Revision::DELETED_TEXT ) ) {
 427                         $deleted = true; // old revisions text is hidden
 428                         if ( $this->mOldRev->isDeleted( Revision::DELETED_RESTRICTED ) )
 429                                 $suppressed = true; // also suppressed
 430                 }
 431                 if ( $this->mNewRev->isDeleted( Revision::DELETED_TEXT ) ) {
 432                         $deleted = true; // new revisions text is hidden
 433                         if ( $this->mNewRev->isDeleted( Revision::DELETED_RESTRICTED ) )
 434                                 $suppressed = true; // also suppressed
 435                 }
 436                 # If the diff cannot be shown due to a deleted revision, then output
 437                 # the diff header and links to unhide (if available)...
 438                 if ( $deleted && ( !$this->unhide || !$allowed ) ) {
 439                         $this->showDiffStyle();
 440                         $multi = $this->getMultiNotice();
 441                         $wgOut->addHTML( $this->addHeader( '', $oldHeader, $newHeader, $multi ) );
 442                         if ( !$allowed ) {
 443                                 $msg = $suppressed ? 'rev-suppressed-no-diff' : 'rev-deleted-no-diff';
 444                                 # Give explanation for why revision is not visible
 445                                 $wgOut->wrapWikiMsg( "<div id='mw-$msg' class='mw-warning plainlinks'>\n$1\n</div>\n",
 446                                         array( $msg ) );
 447                         } else {
 448                                 # Give explanation and add a link to view the diff...
 449                                 $link = $this->mTitle->getFullUrl( array(
 450                                         'diff' => $this->mNewid,
 451                                         'oldid' => $this->mOldid,
 452                                         'unhide' => 1
 453                                 ) );
 454                                 $msg = $suppressed ? 'rev-suppressed-unhide-diff' : 'rev-deleted-unhide-diff';
 455                                 $wgOut->wrapWikiMsg( "<div id='mw-$msg' class='mw-warning plainlinks'>\n$1\n</div>\n", array( $msg, $link ) );
 456                         }
 457                 # Otherwise, output a regular diff...
 458                 } else {
 459                         # Add deletion notice if the user is viewing deleted content
 460                         $notice = '';
 461                         if ( $deleted ) {
 462                                 $msg = $suppressed ? 'rev-suppressed-diff-view' : 'rev-deleted-diff-view';
 463                                 $notice = "<div id='mw-$msg' class='mw-warning plainlinks'>\n" . wfMsgExt( $msg, 'parseinline' ) . "</div>\n";
 464                         }
 465                         $this->showDiff( $oldHeader, $newHeader, $notice );
 466                         if ( !$diffOnly ) {
 467                                 $this->renderNewRevision();
 468                         }
 469                 }
 470                 wfProfileOut( __METHOD__ );
 471         }
 472
 473         /**
 474          * @param $rev Revision
 475          * @return String
 476          */
 477         protected function revisionDeleteLink( $rev ) {
 478                 global $wgUser;
 479                 $link = '';
 480                 $canHide = $wgUser->isAllowed( 'deleterevision' );
 481                 // Show del/undel link if:
 482                 // (a) the user can delete revisions, or
 483                 // (b) the user can view deleted revision *and* this one is deleted
 484                 if ( $canHide || ( $rev->getVisibility() && $wgUser->isAllowed( 'deletedhistory' ) ) ) {
 485                         $sk = $wgUser->getSkin();
 486                         if ( !$rev->userCan( Revision::DELETED_RESTRICTED ) ) {
 487                                 $link = $sk->revDeleteLinkDisabled( $canHide ); // revision was hidden from sysops
 488                         } else {
 489                                 $query = array(
 490                                         'type'   => 'revision',
 491                                         'target' => $rev->mTitle->getPrefixedDbkey(),
 492                                         'ids'    => $rev->getId()
 493                                 );
 494                                 $link = $sk->revDeleteLink( $query,
 495                                         $rev->isDeleted( Revision::DELETED_RESTRICTED ), $canHide );
 496                         }
 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                 global $wgOut, $wgUser;
 507                 wfProfileIn( __METHOD__ );
 508                 # Add "current version as of X" title
 509                 $wgOut->addHTML( "<hr /><h2>{$this->mPagetitle}</h2>\n" );
 510                 # Page content may be handled by a hooked call instead...
 511                 if ( wfRunHooks( 'ArticleContentOnDiff', array( $this, $wgOut ) ) ) {
 512                         # Use the current version parser cache if applicable
 513                         $pCache = true;
 514                         if ( !$this->mNewRev->isCurrent() ) {
 515                                 $oldEditSectionSetting = $wgOut->parserOptions()->setEditSection( false );
 516                                 $pCache = false;
 517                         }
 518
 519                         $this->loadNewText();
 520                         $wgOut->setRevisionId( $this->mNewRev->getId() );
 521
 522                         if ( $this->mTitle->isCssJsSubpage() || $this->mTitle->isCssOrJsPage() ) {
 523                                 // Stolen from Article::view --AG 2007-10-11
 524                                 // Give hooks a chance to customise the output
 525                                 // @TODO: standardize this crap into one function
 526                                 if ( wfRunHooks( 'ShowRawCssJs', array( $this->mNewtext, $this->mTitle, $wgOut ) ) ) {
 527                                         // Wrap the whole lot in a <pre> and don't parse
 528                                         $m = array();
 529                                         preg_match( '!\.(css|js)$!u', $this->mTitle->getText(), $m );
 530                                         $wgOut->addHTML( "<pre class=\"mw-code mw-{$m[1]}\" dir=\"ltr\">\n" );
 531                                         $wgOut->addHTML( htmlspecialchars( $this->mNewtext ) );
 532                                         $wgOut->addHTML( "\n</pre>\n" );
 533                                 }
 534                         } elseif ( $pCache ) {
 535                                 $article = new Article( $this->mTitle, 0 );
 536                                 $pOutput = ParserCache::singleton()->get( $article, $wgOut->parserOptions() );
 537                                 if( $pOutput ) {
 538                                         $wgOut->addParserOutput( $pOutput );
 539                                 } else {
 540                                         $article->doViewParse();
 541                                 }
 542                         } else {
 543                                 $wgOut->addWikiTextTidy( $this->mNewtext );
 544                         }
 545
 546                         if ( !$this->mNewRev->isCurrent() ) {
 547                                 $wgOut->parserOptions()->setEditSection( $oldEditSectionSetting );
 548                         }
 549                 }
 550                 # Add redundant patrol link on bottom...
 551                 if ( $this->mRcidMarkPatrolled && $this->mTitle->quickUserCan( 'patrol' ) ) {
 552                         $sk = $wgUser->getSkin();
 553                         $token = $wgUser->editToken( $this->mRcidMarkPatrolled );
 554                         $wgOut->preventClickjacking();
 555                         $wgOut->addHTML(
 556                                 "<div class='patrollink'>[" . $sk->link(
 557                                         $this->mTitle,
 558                                         wfMsgHtml( 'markaspatrolleddiff' ),
 559                                         array(),
 560                                         array(
 561                                                 'action'        => 'markpatrolled',
 562                                                 'rcid'          => $this->mRcidMarkPatrolled,
 563                                                 'token'         => $token,
 564                                         )
 565                                 ) . ']</div>'
 566                          );
 567                 }
 568
 569                 wfProfileOut( __METHOD__ );
 570         }
 571
 572         /**
 573          * Show the first revision of an article. Uses normal diff headers in
 574          * contrast to normal "old revision" display style.
 575          */
 576         function showFirstRevision() {
 577                 global $wgOut, $wgUser;
 578                 wfProfileIn( __METHOD__ );
 579
 580                 # Get article text from the DB
 581                 #
 582                 if ( ! $this->loadNewText() ) {
 583                         $t = $this->mTitle->getPrefixedText();
 584                         $d = wfMsgExt( 'missingarticle-diff', array( 'escape' ),
 585                                         $this->deletedIdMarker( $this->mOldid ),
 586                                         $this->deletedIdMarker( $this->mNewid ) );
 587                         $wgOut->setPagetitle( wfMsg( 'errorpagetitle' ) );
 588                         $wgOut->addWikiMsg( 'missing-article', "<nowiki>$t</nowiki>", "<span class='plainlinks'>$d</span>" );
 589                         wfProfileOut( __METHOD__ );
 590                         return;
 591                 }
 592                 if ( $this->mNewRev->isCurrent() ) {
 593                         $wgOut->setArticleFlag( true );
 594                 }
 595
 596                 # Check if user is allowed to look at this page. If not, bail out.
 597                 #
 598                 if ( !$this->mTitle->userCanRead() ) {
 599                         $wgOut->loginToUse();
 600                         $wgOut->output();
 601                         wfProfileOut( __METHOD__ );
 602                         throw new MWException( "Permission Error: you do not have access to view this page" );
 603                 }
 604
 605                 # Prepare the header box
 606                 #
 607                 $sk = $wgUser->getSkin();
 608
 609                 $next = $this->mTitle->getNextRevisionID( $this->mNewid );
 610                 if ( !$next ) {
 611                         $nextlink = '';
 612                 } else {
 613                         $nextlink = '<br />' . $sk->link(
 614                                 $this->mTitle,
 615                                 wfMsgHtml( 'nextdiff' ),
 616                                 array(
 617                                         'id' => 'differences-nextlink'
 618                                 ),
 619                                 array(
 620                                         'diff' => 'next',
 621                                         'oldid' => $this->mNewid,
 622                                 ),
 623                                 array(
 624                                         'known',
 625                                         'noclasses'
 626                                 )
 627                         );
 628                 }
 629                 $header = "<div class=\"firstrevisionheader\" style=\"text-align: center\">" .
 630                         $sk->revUserTools( $this->mNewRev ) . "<br />" . $sk->revComment( $this->mNewRev ) . $nextlink . "</div>\n";
 631
 632                 $wgOut->addHTML( $header );
 633
 634                 $wgOut->setSubtitle( wfMsgExt( 'difference', array( 'parseinline' ) ) );
 635                 $wgOut->setRobotPolicy( 'noindex,nofollow' );
 636
 637                 wfProfileOut( __METHOD__ );
 638         }
 639
 640         /**
 641          * Get the diff text, send it to $wgOut
 642          * Returns false if the diff could not be generated, otherwise returns true
 643          *
 644          * @return bool
 645          */
 646         function showDiff( $otitle, $ntitle, $notice = '' ) {
 647                 global $wgOut;
 648                 $diff = $this->getDiff( $otitle, $ntitle, $notice );
 649                 if ( $diff === false ) {
 650                         $wgOut->addWikiMsg( 'missing-article', "<nowiki>(fixme, bug)</nowiki>", '' );
 651                         return false;
 652                 } else {
 653                         $this->showDiffStyle();
 654                         $wgOut->addHTML( $diff );
 655                         return true;
 656                 }
 657         }
 658
 659         /**
 660          * Add style sheets and supporting JS for diff display.
 661          */
 662         function showDiffStyle() {
 663                 global $wgOut;
 664                 $wgOut->addModuleStyles( 'mediawiki.legacy.diff' );
 665         }
 666
 667         /**
 668          * Get complete diff table, including header
 669          *
 670          * @param $otitle Title: old title
 671          * @param $ntitle Title: new title
 672          * @param $notice String: HTML between diff header and body
 673          * @return mixed
 674          */
 675         function getDiff( $otitle, $ntitle, $notice = '' ) {
 676                 $body = $this->getDiffBody();
 677                 if ( $body === false ) {
 678                         return false;
 679                 } else {
 680                         $multi = $this->getMultiNotice();
 681                         return $this->addHeader( $body, $otitle, $ntitle, $multi, $notice );
 682                 }
 683         }
 684
 685         /**
 686          * Get the diff table body, without header
 687          *
 688          * @return mixed (string/false)
 689          */
 690         public function getDiffBody() {
 691                 global $wgMemc;
 692                 wfProfileIn( __METHOD__ );
 693                 $this->mCacheHit = true;
 694                 // Check if the diff should be hidden from this user
 695                 if ( !$this->loadRevisionData() ) {
 696                         wfProfileOut( __METHOD__ );
 697                         return false;
 698                 } elseif ( $this->mOldRev && !$this->mOldRev->userCan( Revision::DELETED_TEXT ) ) {
 699                         wfProfileOut( __METHOD__ );
 700                         return false;
 701                 } elseif ( $this->mNewRev && !$this->mNewRev->userCan( Revision::DELETED_TEXT ) ) {
 702                         wfProfileOut( __METHOD__ );
 703                         return false;
 704                 }
 705                 // Short-circuit
 706                 if ( $this->mOldRev && $this->mNewRev
 707                         && $this->mOldRev->getID() == $this->mNewRev->getID() )
 708                 {
 709                         wfProfileOut( __METHOD__ );
 710                         return '';
 711                 }
 712                 // Cacheable?
 713                 $key = false;
 714                 if ( $this->mOldid && $this->mNewid ) {
 715                         $key = wfMemcKey( 'diff', 'version', MW_DIFF_VERSION,
 716                                 'oldid', $this->mOldid, 'newid', $this->mNewid );
 717                         // Try cache
 718                         if ( !$this->mRefreshCache ) {
 719                                 $difftext = $wgMemc->get( $key );
 720                                 if ( $difftext ) {
 721                                         wfIncrStats( 'diff_cache_hit' );
 722                                         $difftext = $this->localiseLineNumbers( $difftext );
 723                                         $difftext .= "\n<!-- diff cache key $key -->\n";
 724                                         wfProfileOut( __METHOD__ );
 725                                         return $difftext;
 726                                 }
 727                         } // don't try to load but save the result
 728                 }
 729                 $this->mCacheHit = false;
 730
 731                 // Loadtext is permission safe, this just clears out the diff
 732                 if ( !$this->loadText() ) {
 733                         wfProfileOut( __METHOD__ );
 734                         return false;
 735                 }
 736
 737                 $difftext = $this->generateDiffBody( $this->mOldtext, $this->mNewtext );
 738
 739                 // Save to cache for 7 days
 740                 if ( !wfRunHooks( 'AbortDiffCache', array( &$this ) ) ) {
 741                         wfIncrStats( 'diff_uncacheable' );
 742                 } elseif ( $key !== false && $difftext !== false ) {
 743                         wfIncrStats( 'diff_cache_miss' );
 744                         $wgMemc->set( $key, $difftext, 7 * 86400 );
 745                 } else {
 746                         wfIncrStats( 'diff_uncacheable' );
 747                 }
 748                 // Replace line numbers with the text in the user's language
 749                 if ( $difftext !== false ) {
 750                         $difftext = $this->localiseLineNumbers( $difftext );
 751                 }
 752                 wfProfileOut( __METHOD__ );
 753                 return $difftext;
 754         }
 755
 756         /**
 757          * Make sure the proper modules are loaded before we try to
 758          * make the diff
 759          */
 760         private function initDiffEngines() {
 761                 global $wgExternalDiffEngine;
 762                 if ( $wgExternalDiffEngine == 'wikidiff' && !function_exists( 'wikidiff_do_diff' ) ) {
 763                         wfProfileIn( __METHOD__ . '-php_wikidiff.so' );
 764                         wfDl( 'php_wikidiff' );
 765                         wfProfileOut( __METHOD__ . '-php_wikidiff.so' );
 766                 }
 767                 else if ( $wgExternalDiffEngine == 'wikidiff2' && !function_exists( 'wikidiff2_do_diff' ) ) {
 768                         wfProfileIn( __METHOD__ . '-php_wikidiff2.so' );
 769                         wfDl( 'wikidiff2' );
 770                         wfProfileOut( __METHOD__ . '-php_wikidiff2.so' );
 771                 }
 772         }
 773
 774         /**
 775          * Generate a diff, no caching
 776          *
 777          * @param $otext String: old text, must be already segmented
 778          * @param $ntext String: new text, must be already segmented
 779          */
 780         function generateDiffBody( $otext, $ntext ) {
 781                 global $wgExternalDiffEngine, $wgContLang;
 782
 783                 $otext = str_replace( "\r\n", "\n", $otext );
 784                 $ntext = str_replace( "\r\n", "\n", $ntext );
 785
 786                 $this->initDiffEngines();
 787
 788                 if ( $wgExternalDiffEngine == 'wikidiff' && function_exists( 'wikidiff_do_diff' ) ) {
 789                         # For historical reasons, external diff engine expects
 790                         # input text to be HTML-escaped already
 791                         $otext = htmlspecialchars ( $wgContLang->segmentForDiff( $otext ) );
 792                         $ntext = htmlspecialchars ( $wgContLang->segmentForDiff( $ntext ) );
 793                         return $wgContLang->unsegmentForDiff( wikidiff_do_diff( $otext, $ntext, 2 ) ) .
 794                         $this->debug( 'wikidiff1' );
 795                 }
 796
 797                 if ( $wgExternalDiffEngine == 'wikidiff2' && function_exists( 'wikidiff2_do_diff' ) ) {
 798                         # Better external diff engine, the 2 may some day be dropped
 799                         # This one does the escaping and segmenting itself
 800                         wfProfileIn( 'wikidiff2_do_diff' );
 801                         $text = wikidiff2_do_diff( $otext, $ntext, 2 );
 802                         $text .= $this->debug( 'wikidiff2' );
 803                         wfProfileOut( 'wikidiff2_do_diff' );
 804                         return $text;
 805                 }
 806                 if ( $wgExternalDiffEngine != 'wikidiff3' && $wgExternalDiffEngine !== false ) {
 807                         # Diff via the shell
 808                         global $wgTmpDirectory;
 809                         $tempName1 = tempnam( $wgTmpDirectory, 'diff_' );
 810                         $tempName2 = tempnam( $wgTmpDirectory, 'diff_' );
 811
 812                         $tempFile1 = fopen( $tempName1, "w" );
 813                         if ( !$tempFile1 ) {
 814                                 wfProfileOut( __METHOD__ );
 815                                 return false;
 816                         }
 817                         $tempFile2 = fopen( $tempName2, "w" );
 818                         if ( !$tempFile2 ) {
 819                                 wfProfileOut( __METHOD__ );
 820                                 return false;
 821                         }
 822                         fwrite( $tempFile1, $otext );
 823                         fwrite( $tempFile2, $ntext );
 824                         fclose( $tempFile1 );
 825                         fclose( $tempFile2 );
 826                         $cmd = wfEscapeShellArg( $wgExternalDiffEngine, $tempName1, $tempName2 );
 827                         wfProfileIn( __METHOD__ . "-shellexec" );
 828                         $difftext = wfShellExec( $cmd );
 829                         $difftext .= $this->debug( "external $wgExternalDiffEngine" );
 830                         wfProfileOut( __METHOD__ . "-shellexec" );
 831                         unlink( $tempName1 );
 832                         unlink( $tempName2 );
 833                         wfProfileOut( __METHOD__ );
 834                         return $difftext;
 835                 }
 836
 837                 # Native PHP diff
 838                 $ota = explode( "\n", $wgContLang->segmentForDiff( $otext ) );
 839                 $nta = explode( "\n", $wgContLang->segmentForDiff( $ntext ) );
 840                 $diffs = new Diff( $ota, $nta );
 841                 $formatter = new TableDiffFormatter();
 842                 $difftext = $wgContLang->unsegmentForDiff( $formatter->format( $diffs ) ) .
 843                 wfProfileOut( __METHOD__ );
 844                 return $difftext;
 845         }
 846
 847         /**
 848          * Generate a debug comment indicating diff generating time,
 849          * server node, and generator backend.
 850          */
 851         protected function debug( $generator = "internal" ) {
 852                 global $wgShowHostnames;
 853                 if ( !$this->enableDebugComment ) {
 854                         return '';
 855                 }
 856                 $data = array( $generator );
 857                 if ( $wgShowHostnames ) {
 858                         $data[] = wfHostname();
 859                 }
 860                 $data[] = wfTimestamp( TS_DB );
 861                 return "<!-- diff generator: " .
 862                 implode( " ",
 863                 array_map(
 864                                         "htmlspecialchars",
 865                 $data ) ) .
 866                         " -->\n";
 867         }
 868
 869         /**
 870          * Replace line numbers with the text in the user's language
 871          */
 872         function localiseLineNumbers( $text ) {
 873                 return preg_replace_callback( '/<!--LINE (\d+)-->/',
 874                 array( &$this, 'localiseLineNumbersCb' ), $text );
 875         }
 876
 877         function localiseLineNumbersCb( $matches ) {
 878                 global $wgLang;
 879                 if ( $matches[1] === '1' && $this->mReducedLineNumbers ) return '';
 880                 return wfMsgExt( 'lineno', 'escape', $wgLang->formatNum( $matches[1] ) );
 881         }
 882
 883
 884         /**
 885          * If there are revisions between the ones being compared, return a note saying so.
 886          * @return string
 887          */
 888         function getMultiNotice() {
 889                 if ( !is_object( $this->mOldRev ) || !is_object( $this->mNewRev ) ) {
 890                         return '';
 891                 } elseif ( !$this->mOldPage->equals( $this->mNewPage ) ) {
 892                         // Comparing two different pages? Count would be meaningless.
 893                         return '';
 894                 }
 895
 896                 if ( $this->mOldRev->getTimestamp() > $this->mNewRev->getTimestamp() ) {
 897                         $oldRev = $this->mNewRev; // flip
 898                         $newRev = $this->mOldRev; // flip
 899                 } else { // normal case
 900                         $oldRev = $this->mOldRev;
 901                         $newRev = $this->mNewRev;
 902                 }
 903
 904                 $nEdits = $this->mTitle->countRevisionsBetween( $oldRev, $newRev );
 905                 if ( $nEdits > 0 ) {
 906                         $limit = 100; // use diff-multi-manyusers if too many users
 907                         $numUsers = $this->mTitle->countAuthorsBetween( $oldRev, $newRev, $limit );
 908                         return self::intermediateEditsMsg( $nEdits, $numUsers, $limit );
 909                 }
 910                 return ''; // nothing
 911         }
 912
 913         /**
 914          * Get a notice about how many intermediate edits and users there are
 915          * @param $numEdits int
 916          * @param $numUsers int
 917          * @param $limit int
 918          * @return string
 919          */
 920         public static function intermediateEditsMsg( $numEdits, $numUsers, $limit ) {
 921                 global $wgLang;
 922                 if ( $numUsers > $limit ) {
 923                         $msg = 'diff-multi-manyusers';
 924                         $numUsers = $limit;
 925                 } else {
 926                         $msg = 'diff-multi';
 927                 }
 928                 return wfMsgExt( $msg, 'parseinline',
 929                         $wgLang->formatnum( $numEdits ), $wgLang->formatnum( $numUsers ) );
 930         }
 931
 932         /**
 933          * Add the header to a diff body
 934          *
 935          * @return string
 936          */
 937         static function addHeader( $diff, $otitle, $ntitle, $multi = '', $notice = '' ) {
 938                 $header = "<table class='diff'>";
 939                 if ( $diff ) { // Safari/Chrome show broken output if cols not used
 940                         $header .= "
 941                         <col class='diff-marker' />
 942                         <col class='diff-content' />
 943                         <col class='diff-marker' />
 944                         <col class='diff-content' />";
 945                         $colspan = 2;
 946                         $multiColspan = 4;
 947                 } else {
 948                         $colspan = 1;
 949                         $multiColspan = 2;
 950                 }
 951                 $header .= "
 952                 <tr valign='top'>
 953                 <td colspan='$colspan' class='diff-otitle'>{$otitle}</td>
 954                 <td colspan='$colspan' class='diff-ntitle'>{$ntitle}</td>
 955                 </tr>";
 956
 957                 if ( $multi != '' ) {
 958                         $header .= "<tr><td colspan='{$multiColspan}' align='center' class='diff-multi'>{$multi}</td></tr>";
 959                 }
 960                 if ( $notice != '' ) {
 961                         $header .= "<tr><td colspan='{$multiColspan}' align='center'>{$notice}</td></tr>";
 962                 }
 963
 964                 return $header . $diff . "</table>";
 965         }
 966
 967         /**
 968          * Use specified text instead of loading from the database
 969          */
 970         function setText( $oldText, $newText ) {
 971                 $this->mOldtext = $oldText;
 972                 $this->mNewtext = $newText;
 973                 $this->mTextLoaded = 2;
 974                 $this->mRevisionsLoaded = true;
 975         }
 976
 977         /**
 978          * Load revision metadata for the specified articles. If newid is 0, then compare
 979          * the old article in oldid to the current article; if oldid is 0, then
 980          * compare the current article to the immediately previous one (ignoring the
 981          * value of newid).
 982          *
 983          * If oldid is false, leave the corresponding revision object set
 984          * to false. This is impossible via ordinary user input, and is provided for
 985          * API convenience.
 986          *
 987          * @return bool
 988          */
 989         function loadRevisionData() {
 990                 global $wgLang, $wgUser;
 991                 if ( $this->mRevisionsLoaded ) {
 992                         return true;
 993                 } else {
 994                         // Whether it succeeds or fails, we don't want to try again
 995                         $this->mRevisionsLoaded = true;
 996                 }
 997
 998                 // Load the new revision object
 999                 $this->mNewRev = $this->mNewid
1000                         ? Revision::newFromId( $this->mNewid )
1001                         : Revision::newFromTitle( $this->mTitle );
1002                 if ( !$this->mNewRev instanceof Revision ) {
1003                         return false;
1004                 }
1005
1006                 // Update the new revision ID in case it was 0 (makes life easier doing UI stuff)
1007                 $this->mNewid = $this->mNewRev->getId();
1008
1009                 // Check if page is editable
1010                 $editable = $this->mNewRev->getTitle()->userCan( 'edit' );
1011
1012                 // Set assorted variables
1013                 $timestamp = $wgLang->timeanddate( $this->mNewRev->getTimestamp(), true );
1014                 $dateofrev = $wgLang->date( $this->mNewRev->getTimestamp(), true );
1015                 $timeofrev = $wgLang->time( $this->mNewRev->getTimestamp(), true );
1016                 $this->mNewPage = $this->mNewRev->getTitle();
1017                 if ( $this->mNewRev->isCurrent() ) {
1018                         $newLink = $this->mNewPage->escapeLocalUrl( array(
1019                                 'oldid' => $this->mNewid
1020                         ) );
1021                         $this->mPagetitle = htmlspecialchars( wfMsg(
1022                                 'currentrev-asof',
1023                                 $timestamp,
1024                                 $dateofrev,
1025                                 $timeofrev
1026                         ) );
1027                         $newEdit = $this->mNewPage->escapeLocalUrl( array(
1028                                 'action' => 'edit'
1029                         ) );
1030
1031                         $this->mNewtitle = "<a href='$newLink'>{$this->mPagetitle}</a>";
1032                         $this->mNewtitle .= " (<a href='$newEdit'>" . wfMsgHtml( $editable ? 'editold' : 'viewsourceold' ) . "</a>)";
1033                 } else {
1034                         $newLink = $this->mNewPage->escapeLocalUrl( array(
1035                                 'oldid' => $this->mNewid
1036                         ) );
1037                         $newEdit = $this->mNewPage->escapeLocalUrl( array(
1038                                 'action' => 'edit',
1039                                 'oldid' => $this->mNewid
1040                         ) );
1041                         $this->mPagetitle = htmlspecialchars( wfMsg(
1042                                 'revisionasof',
1043                                 $timestamp,
1044                                 $dateofrev,
1045                                 $timeofrev
1046                         ) );
1047
1048                         $this->mNewtitle = "<a href='$newLink'>{$this->mPagetitle}</a>";
1049                         $this->mNewtitle .= " (<a href='$newEdit'>" . wfMsgHtml( $editable ? 'editold' : 'viewsourceold' ) . "</a>)";
1050                 }
1051                 if ( !$this->mNewRev->userCan( Revision::DELETED_TEXT ) ) {
1052                         $this->mNewtitle = "<span class='history-deleted'>{$this->mPagetitle}</span>";
1053                 } else if ( $this->mNewRev->isDeleted( Revision::DELETED_TEXT ) ) {
1054                         $this->mNewtitle = "<span class='history-deleted'>{$this->mNewtitle}</span>";
1055                 }
1056
1057                 // Load the old revision object
1058                 $this->mOldRev = false;
1059                 if ( $this->mOldid ) {
1060                         $this->mOldRev = Revision::newFromId( $this->mOldid );
1061                 } elseif ( $this->mOldid === 0 ) {
1062                         $rev = $this->mNewRev->getPrevious();
1063                         if ( $rev ) {
1064                                 $this->mOldid = $rev->getId();
1065                                 $this->mOldRev = $rev;
1066                         } else {
1067                                 // No previous revision; mark to show as first-version only.
1068                                 $this->mOldid = false;
1069                                 $this->mOldRev = false;
1070                         }
1071                 } /* elseif ( $this->mOldid === false ) leave mOldRev false; */
1072
1073                 if ( is_null( $this->mOldRev ) ) {
1074                         return false;
1075                 }
1076
1077                 if ( $this->mOldRev ) {
1078                         $this->mOldPage = $this->mOldRev->getTitle();
1079
1080                         $t = $wgLang->timeanddate( $this->mOldRev->getTimestamp(), true );
1081                         $dateofrev = $wgLang->date( $this->mOldRev->getTimestamp(), true );
1082                         $timeofrev = $wgLang->time( $this->mOldRev->getTimestamp(), true );
1083                         $oldLink = $this->mOldPage->escapeLocalUrl( array(
1084                                 'oldid' => $this->mOldid
1085                         ) );
1086                         $oldEdit = $this->mOldPage->escapeLocalUrl( array(
1087                                 'action' => 'edit',
1088                                 'oldid' => $this->mOldid
1089                         ) );
1090                         $this->mOldPagetitle = htmlspecialchars( wfMsg( 'revisionasof', $t, $dateofrev, $timeofrev ) );
1091
1092                         $this->mOldtitle = "<a href='$oldLink'>{$this->mOldPagetitle}</a>"
1093                         . " (<a href='$oldEdit'>" . wfMsgHtml( $editable ? 'editold' : 'viewsourceold' ) . "</a>)";
1094                         // Add an "undo" link
1095                         if ( $editable && !$this->mOldRev->isDeleted( Revision::DELETED_TEXT ) && !$this->mNewRev->isDeleted( Revision::DELETED_TEXT ) ) {
1096                                 $undoLink = Html::element( 'a', array(
1097                                         'href' => $this->mNewPage->getLocalUrl( array(
1098                                                 'action' => 'edit',
1099                                                 'undoafter' => $this->mOldid,
1100                                                 'undo' => $this->mNewid ) ),
1101                                         'title' => $wgUser->getSkin()->titleAttrib( 'undo' )
1102                                 ), wfMsg( 'editundo' ) );
1103                                 $this->mNewtitle .= ' (' . $undoLink . ')';
1104                         }
1105
1106                         if ( !$this->mOldRev->userCan( Revision::DELETED_TEXT ) ) {
1107                                 $this->mOldtitle = '<span class="history-deleted">' . $this->mOldPagetitle . '</span>';
1108                         } else if ( $this->mOldRev->isDeleted( Revision::DELETED_TEXT ) ) {
1109                                 $this->mOldtitle = '<span class="history-deleted">' . $this->mOldtitle . '</span>';
1110                         }
1111                 }
1112
1113                 return true;
1114         }
1115
1116         /**
1117          * Load the text of the revisions, as well as revision data.
1118          *
1119          * @return bool
1120          */
1121         function loadText() {
1122                 if ( $this->mTextLoaded == 2 ) {
1123                         return true;
1124                 } else {
1125                         // Whether it succeeds or fails, we don't want to try again
1126                         $this->mTextLoaded = 2;
1127                 }
1128
1129                 if ( !$this->loadRevisionData() ) {
1130                         return false;
1131                 }
1132                 if ( $this->mOldRev ) {
1133                         $this->mOldtext = $this->mOldRev->getText( Revision::FOR_THIS_USER );
1134                         if ( $this->mOldtext === false ) {
1135                                 return false;
1136                         }
1137                 }
1138                 if ( $this->mNewRev ) {
1139                         $this->mNewtext = $this->mNewRev->getText( Revision::FOR_THIS_USER );
1140                         if ( $this->mNewtext === false ) {
1141                                 return false;
1142                         }
1143                 }
1144                 return true;
1145         }
1146
1147         /**
1148          * Load the text of the new revision, not the old one
1149          *
1150          * @return bool
1151          */
1152         function loadNewText() {
1153                 if ( $this->mTextLoaded >= 1 ) {
1154                         return true;
1155                 } else {
1156                         $this->mTextLoaded = 1;
1157                 }
1158                 if ( !$this->loadRevisionData() ) {
1159                         return false;
1160                 }
1161                 $this->mNewtext = $this->mNewRev->getText( Revision::FOR_THIS_USER );
1162                 return true;
1163         }
1164 }