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 ( $wgUser->isAllowed( 'deletedhistory' ) && !$wgUser->isBlocked() ) {
 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 $wgCanonicalServer, $wgScript, $wgLang;
 194                         $wgOut->disable();
 195                         header ( "Content-type: application/x-external-editor; charset=UTF-8" );
 196                         $url1 = $this->mTitle->getCanonical( array(
 197                                 'action' => 'raw',
 198                                 'oldid' => $this->mOldid
 199                         ) );
 200                         $url2 = $this->mTitle->getCanonical( array(
 201                                 'action' => 'raw',
 202                                 'oldid' => $this->mNewid
 203                         ) );
 204                         $special = $wgLang->getNsText( NS_SPECIAL );
 205                         $control = <<<CONTROL
 206                         [Process]
 207                         Type=Diff text
 208                         Engine=MediaWiki
 209                         Script={$wgCanonicalServer}{$wgScript}
 210                         Special namespace={$special}
 211
 212                         [File]
 213                         Extension=wiki
 214                         URL=$url1
 215
 216                         [File 2]
 217                         Extension=wiki
 218                         URL=$url2
 219 CONTROL;
 220                         echo( $control );
 221
 222                         wfProfileOut( __METHOD__ );
 223                         return;
 224                 }
 225
 226                 if ( !$this->loadRevisionData() ) {
 227                         // Sounds like a deleted revision... Let's see what we can do.
 228                         $t = $this->mTitle->getPrefixedText();
 229                         $d = wfMsgExt( 'missingarticle-diff', array( 'escape' ),
 230                                 $this->deletedIdMarker( $this->mOldid ),
 231                                 $this->deletedIdMarker( $this->mNewid ) );
 232                         $wgOut->setPagetitle( wfMsg( 'errorpagetitle' ) );
 233                         $wgOut->addWikiMsg( 'missing-article', "<nowiki>$t</nowiki>", "<span class='plainlinks'>$d</span>" );
 234                         wfProfileOut( __METHOD__ );
 235                         return;
 236                 }
 237
 238                 wfRunHooks( 'DiffViewHeader', array( $this, $this->mOldRev, $this->mNewRev ) );
 239
 240                 # mOldid is false if the difference engine is called with a "vague" query for
 241                 # a diff between a version V and its previous version V' AND the version V
 242                 # is the first version of that article. In that case, V' does not exist.
 243                 if ( $this->mOldid === false ) {
 244                         $this->showFirstRevision();
 245                         $this->renderNewRevision();  // should we respect $diffOnly here or not?
 246                         wfProfileOut( __METHOD__ );
 247                         return;
 248                 }
 249
 250                 $oldTitle = $this->mOldPage->getPrefixedText();
 251                 $newTitle = $this->mNewPage->getPrefixedText();
 252                 if ( $oldTitle == $newTitle ) {
 253                         $wgOut->setPageTitle( $newTitle );
 254                 } else {
 255                         $wgOut->setPageTitle( $oldTitle . ', ' . $newTitle );
 256                 }
 257                 if ( $this->mNewPage->equals( $this->mOldPage ) ) {
 258                         $wgOut->setSubtitle( wfMsgExt( 'difference', array( 'parseinline' ) ) );
 259                 } else {
 260                         $wgOut->setSubtitle( wfMsgExt( 'difference-multipage', array( 'parseinline' ) ) );
 261                 }
 262                 $wgOut->setRobotPolicy( 'noindex,nofollow' );
 263
 264                 if ( !$this->mOldPage->userCanRead() || !$this->mNewPage->userCanRead() ) {
 265                         $wgOut->loginToUse();
 266                         $wgOut->output();
 267                         $wgOut->disable();
 268                         wfProfileOut( __METHOD__ );
 269                         return;
 270                 }
 271
 272                 $sk = $wgUser->getSkin();
 273                 if ( method_exists( $sk, 'suppressQuickbar' ) ) {
 274                         $sk->suppressQuickbar();
 275                 }
 276
 277                 // Check if page is editable
 278                 $editable = $this->mNewRev->getTitle()->userCan( 'edit' );
 279                 if ( $editable && $this->mNewRev->isCurrent() && $wgUser->isAllowed( 'rollback' ) ) {
 280                         $wgOut->preventClickjacking();
 281                         $rollback = '&#160;&#160;&#160;' . $sk->generateRollback( $this->mNewRev );
 282                 } else {
 283                         $rollback = '';
 284                 }
 285
 286                 // Prepare a change patrol link, if applicable
 287                 if ( $wgUseRCPatrol && $this->mTitle->userCan( 'patrol' ) ) {
 288                         // If we've been given an explicit change identifier, use it; saves time
 289                         if ( $this->mRcidMarkPatrolled ) {
 290                                 $rcid = $this->mRcidMarkPatrolled;
 291                                 $rc = RecentChange::newFromId( $rcid );
 292                                 // Already patrolled?
 293                                 $rcid = is_object( $rc ) && !$rc->getAttribute( 'rc_patrolled' ) ? $rcid : 0;
 294                         } else {
 295                                 // Look for an unpatrolled change corresponding to this diff
 296                                 $db = wfGetDB( DB_SLAVE );
 297                                 $change = RecentChange::newFromConds(
 298                                         array(
 299                                         // Redundant user,timestamp condition so we can use the existing index
 300                                                 'rc_user_text'  => $this->mNewRev->getRawUserText(),
 301                                                 'rc_timestamp'  => $db->timestamp( $this->mNewRev->getTimestamp() ),
 302                                                 'rc_this_oldid' => $this->mNewid,
 303                                                 'rc_last_oldid' => $this->mOldid,
 304                                                 'rc_patrolled'  => 0
 305                                         ),
 306                                         __METHOD__
 307                                 );
 308                                 if ( $change instanceof RecentChange ) {
 309                                         $rcid = $change->mAttribs['rc_id'];
 310                                         $this->mRcidMarkPatrolled = $rcid;
 311                                 } else {
 312                                         // None found
 313                                         $rcid = 0;
 314                                 }
 315                         }
 316                         // Build the link
 317                         if ( $rcid ) {
 318                                 $wgOut->preventClickjacking();
 319                                 $token = $wgUser->editToken( $rcid );
 320                                 $patrol = ' <span class="patrollink">[' . $sk->link(
 321                                         $this->mTitle,
 322                                         wfMsgHtml( 'markaspatrolleddiff' ),
 323                                         array(),
 324                                         array(
 325                                                 'action' => 'markpatrolled',
 326                                                 'rcid' => $rcid,
 327                                                 'token' => $token,
 328                                         ),
 329                                         array(
 330                                                 'known',
 331                                                 'noclasses'
 332                                         )
 333                                 ) . ']</span>';
 334                         } else {
 335                                 $patrol = '';
 336                         }
 337                 } else {
 338                         $patrol = '';
 339                 }
 340
 341                 # Carry over 'diffonly' param via navigation links
 342                 if ( $diffOnly != $wgUser->getBoolOption( 'diffonly' ) ) {
 343                         $query['diffonly'] = $diffOnly;
 344                 }
 345
 346                 # Make "previous revision link"
 347                 $query['diff'] = 'prev';
 348                 $query['oldid'] = $this->mOldid;
 349                 # Cascade unhide param in links for easy deletion browsing
 350                 if ( $this->unhide ) {
 351                         $query['unhide'] = 1;
 352                 }
 353                 if ( !$this->mOldRev->getPrevious() ) {
 354                         $prevlink = '&#160;';
 355                 } else {
 356                         $prevlink = $sk->link(
 357                                 $this->mTitle,
 358                                 wfMsgHtml( 'previousdiff' ),
 359                                 array(
 360                                         'id' => 'differences-prevlink'
 361                                 ),
 362                                 $query,
 363                                 array(
 364                                         'known',
 365                                         'noclasses'
 366                                 )
 367                         );
 368                 }
 369
 370                 # Make "next revision link"
 371                 $query['diff'] = 'next';
 372                 $query['oldid'] = $this->mNewid;
 373                 # Skip next link on the top revision
 374                 if ( $this->mNewRev->isCurrent() ) {
 375                         $nextlink = '&#160;';
 376                 } else {
 377                         $nextlink = $sk->link(
 378                                 $this->mTitle,
 379                                 wfMsgHtml( 'nextdiff' ),
 380                                 array(
 381                                         'id' => 'differences-nextlink'
 382                                 ),
 383                                 $query,
 384                                 array(
 385                                         'known',
 386                                         'noclasses'
 387                                 )
 388                         );
 389                 }
 390
 391                 $oldminor = '';
 392                 $newminor = '';
 393
 394                 if ( $this->mOldRev->isMinor() ) {
 395                         $oldminor = ChangesList::flag( 'minor' );
 396                 }
 397                 if ( $this->mNewRev->isMinor() ) {
 398                         $newminor = ChangesList::flag( 'minor' );
 399                 }
 400
 401                 # Handle RevisionDelete links...
 402                 $ldel = $this->revisionDeleteLink( $this->mOldRev );
 403                 $rdel = $this->revisionDeleteLink( $this->mNewRev );
 404
 405                 $oldHeader = '<div id="mw-diff-otitle1"><strong>' . $this->mOldtitle . '</strong></div>' .
 406                         '<div id="mw-diff-otitle2">' .
 407                                 $sk->revUserTools( $this->mOldRev, !$this->unhide ) . '</div>' .
 408                         '<div id="mw-diff-otitle3">' . $oldminor .
 409                                 $sk->revComment( $this->mOldRev, !$diffOnly, !$this->unhide ) . $ldel . '</div>' .
 410                         '<div id="mw-diff-otitle4">' . $prevlink . '</div>';
 411                 $newHeader = '<div id="mw-diff-ntitle1"><strong>' . $this->mNewtitle . '</strong></div>' .
 412                         '<div id="mw-diff-ntitle2">' . $sk->revUserTools( $this->mNewRev, !$this->unhide ) .
 413                                 " $rollback</div>" .
 414                         '<div id="mw-diff-ntitle3">' . $newminor .
 415                                 $sk->revComment( $this->mNewRev, !$diffOnly, !$this->unhide ) . $rdel . '</div>' .
 416                         '<div id="mw-diff-ntitle4">' . $nextlink . $patrol . '</div>';
 417
 418                 # Check if this user can see the revisions
 419                 $allowed = $this->mOldRev->userCan( Revision::DELETED_TEXT )
 420                         && $this->mNewRev->userCan( Revision::DELETED_TEXT );
 421                 # Check if one of the revisions is deleted/suppressed
 422                 $deleted = $suppressed = false;
 423                 if ( $this->mOldRev->isDeleted( Revision::DELETED_TEXT ) ) {
 424                         $deleted = true; // old revisions text is hidden
 425                         if ( $this->mOldRev->isDeleted( Revision::DELETED_RESTRICTED ) )
 426                                 $suppressed = true; // also suppressed
 427                 }
 428                 if ( $this->mNewRev->isDeleted( Revision::DELETED_TEXT ) ) {
 429                         $deleted = true; // new revisions text is hidden
 430                         if ( $this->mNewRev->isDeleted( Revision::DELETED_RESTRICTED ) )
 431                                 $suppressed = true; // also suppressed
 432                 }
 433                 # If the diff cannot be shown due to a deleted revision, then output
 434                 # the diff header and links to unhide (if available)...
 435                 if ( $deleted && ( !$this->unhide || !$allowed ) ) {
 436                         $this->showDiffStyle();
 437                         $multi = $this->getMultiNotice();
 438                         $wgOut->addHTML( $this->addHeader( '', $oldHeader, $newHeader, $multi ) );
 439                         if ( !$allowed ) {
 440                                 $msg = $suppressed ? 'rev-suppressed-no-diff' : 'rev-deleted-no-diff';
 441                                 # Give explanation for why revision is not visible
 442                                 $wgOut->wrapWikiMsg( "<div id='mw-$msg' class='mw-warning plainlinks'>\n$1\n</div>\n",
 443                                         array( $msg ) );
 444                         } else {
 445                                 # Give explanation and add a link to view the diff...
 446                                 $link = $this->mTitle->getFullUrl( array(
 447                                         'diff' => $this->mNewid,
 448                                         'oldid' => $this->mOldid,
 449                                         'unhide' => 1
 450                                 ) );
 451                                 $msg = $suppressed ? 'rev-suppressed-unhide-diff' : 'rev-deleted-unhide-diff';
 452                                 $wgOut->wrapWikiMsg( "<div id='mw-$msg' class='mw-warning plainlinks'>\n$1\n</div>\n", array( $msg, $link ) );
 453                         }
 454                 # Otherwise, output a regular diff...
 455                 } else {
 456                         # Add deletion notice if the user is viewing deleted content
 457                         $notice = '';
 458                         if ( $deleted ) {
 459                                 $msg = $suppressed ? 'rev-suppressed-diff-view' : 'rev-deleted-diff-view';
 460                                 $notice = "<div id='mw-$msg' class='mw-warning plainlinks'>\n" . wfMsgExt( $msg, 'parseinline' ) . "</div>\n";
 461                         }
 462                         $this->showDiff( $oldHeader, $newHeader, $notice );
 463                         if ( !$diffOnly ) {
 464                                 $this->renderNewRevision();
 465                         }
 466                 }
 467                 wfProfileOut( __METHOD__ );
 468         }
 469
 470         /**
 471          * @param $rev Revision
 472          * @return String
 473          */
 474         protected function revisionDeleteLink( $rev ) {
 475                 global $wgUser;
 476                 $link = '';
 477                 $canHide = $wgUser->isAllowed( 'deleterevision' );
 478                 // Show del/undel link if:
 479                 // (a) the user can delete revisions, or
 480                 // (b) the user can view deleted revision *and* this one is deleted
 481                 if ( $canHide || ( $rev->getVisibility() && $wgUser->isAllowed( 'deletedhistory' ) ) ) {
 482                         $sk = $wgUser->getSkin();
 483                         if ( !$rev->userCan( Revision::DELETED_RESTRICTED ) ) {
 484                                 $link = $sk->revDeleteLinkDisabled( $canHide ); // revision was hidden from sysops
 485                         } else {
 486                                 $query = array(
 487                                         'type'   => 'revision',
 488                                         'target' => $rev->mTitle->getPrefixedDbkey(),
 489                                         'ids'    => $rev->getId()
 490                                 );
 491                                 $link = $sk->revDeleteLink( $query,
 492                                         $rev->isDeleted( Revision::DELETED_RESTRICTED ), $canHide );
 493                         }
 494                         $link = '&#160;&#160;&#160;' . $link . ' ';
 495                 }
 496                 return $link;
 497         }
 498
 499         /**
 500          * Show the new revision of the page.
 501          */
 502         function renderNewRevision() {
 503                 global $wgOut, $wgUser;
 504                 wfProfileIn( __METHOD__ );
 505                 # Add "current version as of X" title
 506                 $wgOut->addHTML( "<hr class='diff-hr' />
 507                 <h2 class='diff-currentversion-title'>{$this->mPagetitle}</h2>\n" );
 508                 # Page content may be handled by a hooked call instead...
 509                 if ( wfRunHooks( 'ArticleContentOnDiff', array( $this, $wgOut ) ) ) {
 510                         # Use the current version parser cache if applicable
 511                         $pCache = true;
 512                         if ( !$this->mNewRev->isCurrent() ) {
 513                                 $oldEditSectionSetting = $wgOut->parserOptions()->setEditSection( false );
 514                                 $pCache = false;
 515                         }
 516
 517                         $this->loadNewText();
 518                         $wgOut->setRevisionId( $this->mNewRev->getId() );
 519                         $wgOut->setArticleFlag( true );
 520
 521                         if ( $this->mTitle->isCssJsSubpage() || $this->mTitle->isCssOrJsPage() ) {
 522                                 // Stolen from Article::view --AG 2007-10-11
 523                                 // Give hooks a chance to customise the output
 524                                 // @TODO: standardize this crap into one function
 525                                 if ( wfRunHooks( 'ShowRawCssJs', array( $this->mNewtext, $this->mTitle, $wgOut ) ) ) {
 526                                         // Wrap the whole lot in a <pre> and don't parse
 527                                         $m = array();
 528                                         preg_match( '!\.(css|js)$!u', $this->mTitle->getText(), $m );
 529                                         $wgOut->addHTML( "<pre class=\"mw-code mw-{$m[1]}\" dir=\"ltr\">\n" );
 530                                         $wgOut->addHTML( htmlspecialchars( $this->mNewtext ) );
 531                                         $wgOut->addHTML( "\n</pre>\n" );
 532                                 }
 533                         } elseif ( $pCache ) {
 534                                 $article = new Article( $this->mTitle, 0 );
 535                                 $pOutput = ParserCache::singleton()->get( $article, $wgOut->parserOptions() );
 536                                 if( $pOutput ) {
 537                                         $wgOut->addParserOutput( $pOutput );
 538                                 } else {
 539                                         $article->doViewParse();
 540                                 }
 541                         } else {
 542                                 $wgOut->addWikiTextTidy( $this->mNewtext );
 543                         }
 544
 545                         if ( !$this->mNewRev->isCurrent() ) {
 546                                 $wgOut->parserOptions()->setEditSection( $oldEditSectionSetting );
 547                         }
 548                 }
 549                 # Add redundant patrol link on bottom...
 550                 if ( $this->mRcidMarkPatrolled && $this->mTitle->quickUserCan( 'patrol' ) ) {
 551                         $sk = $wgUser->getSkin();
 552                         $token = $wgUser->editToken( $this->mRcidMarkPatrolled );
 553                         $wgOut->preventClickjacking();
 554                         $wgOut->addHTML(
 555                                 "<div class='patrollink'>[" . $sk->link(
 556                                         $this->mTitle,
 557                                         wfMsgHtml( 'markaspatrolleddiff' ),
 558                                         array(),
 559                                         array(
 560                                                 'action'        => 'markpatrolled',
 561                                                 'rcid'          => $this->mRcidMarkPatrolled,
 562                                                 'token'         => $token,
 563                                         )
 564                                 ) . ']</div>'
 565                          );
 566                 }
 567
 568                 wfProfileOut( __METHOD__ );
 569         }
 570
 571         /**
 572          * Show the first revision of an article. Uses normal diff headers in
 573          * contrast to normal "old revision" display style.
 574          */
 575         function showFirstRevision() {
 576                 global $wgOut, $wgUser;
 577                 wfProfileIn( __METHOD__ );
 578
 579                 # Get article text from the DB
 580                 #
 581                 if ( ! $this->loadNewText() ) {
 582                         $t = $this->mTitle->getPrefixedText();
 583                         $d = wfMsgExt( 'missingarticle-diff', array( 'escape' ),
 584                                         $this->deletedIdMarker( $this->mOldid ),
 585                                         $this->deletedIdMarker( $this->mNewid ) );
 586                         $wgOut->setPagetitle( wfMsg( 'errorpagetitle' ) );
 587                         $wgOut->addWikiMsg( 'missing-article', "<nowiki>$t</nowiki>", "<span class='plainlinks'>$d</span>" );
 588                         wfProfileOut( __METHOD__ );
 589                         return;
 590                 }
 591
 592                 # Check if user is allowed to look at this page. If not, bail out.
 593                 if ( !$this->mTitle->userCanRead() ) {
 594                         $wgOut->loginToUse();
 595                         $wgOut->output();
 596                         wfProfileOut( __METHOD__ );
 597                         throw new MWException( "Permission Error: you do not have access to view this page" );
 598                 }
 599
 600                 # Prepare the header box
 601                 #
 602                 $sk = $wgUser->getSkin();
 603
 604                 $next = $this->mTitle->getNextRevisionID( $this->mNewid );
 605                 if ( !$next ) {
 606                         $nextlink = '';
 607                 } else {
 608                         $nextlink = '<br />' . $sk->link(
 609                                 $this->mTitle,
 610                                 wfMsgHtml( 'nextdiff' ),
 611                                 array(
 612                                         'id' => 'differences-nextlink'
 613                                 ),
 614                                 array(
 615                                         'diff' => 'next',
 616                                         'oldid' => $this->mNewid,
 617                                 ),
 618                                 array(
 619                                         'known',
 620                                         'noclasses'
 621                                 )
 622                         );
 623                 }
 624                 $header = "<div class=\"firstrevisionheader\" style=\"text-align: center\">" .
 625                         $sk->revUserTools( $this->mNewRev ) . "<br />" . $sk->revComment( $this->mNewRev ) . $nextlink . "</div>\n";
 626
 627                 $wgOut->addHTML( $header );
 628
 629                 $wgOut->setSubtitle( wfMsgExt( 'difference', array( 'parseinline' ) ) );
 630                 $wgOut->setRobotPolicy( 'noindex,nofollow' );
 631
 632                 wfProfileOut( __METHOD__ );
 633         }
 634
 635         /**
 636          * Get the diff text, send it to $wgOut
 637          * Returns false if the diff could not be generated, otherwise returns true
 638          *
 639          * @return bool
 640          */
 641         function showDiff( $otitle, $ntitle, $notice = '' ) {
 642                 global $wgOut;
 643                 $diff = $this->getDiff( $otitle, $ntitle, $notice );
 644                 if ( $diff === false ) {
 645                         $wgOut->addWikiMsg( 'missing-article', "<nowiki>(fixme, bug)</nowiki>", '' );
 646                         return false;
 647                 } else {
 648                         $this->showDiffStyle();
 649                         $wgOut->addHTML( $diff );
 650                         return true;
 651                 }
 652         }
 653
 654         /**
 655          * Add style sheets and supporting JS for diff display.
 656          */
 657         function showDiffStyle() {
 658                 global $wgOut;
 659                 $wgOut->addModuleStyles( 'mediawiki.action.history.diff' );
 660         }
 661
 662         /**
 663          * Get complete diff table, including header
 664          *
 665          * @param $otitle Title: old title
 666          * @param $ntitle Title: new title
 667          * @param $notice String: HTML between diff header and body
 668          * @return mixed
 669          */
 670         function getDiff( $otitle, $ntitle, $notice = '' ) {
 671                 $body = $this->getDiffBody();
 672                 if ( $body === false ) {
 673                         return false;
 674                 } else {
 675                         $multi = $this->getMultiNotice();
 676                         return $this->addHeader( $body, $otitle, $ntitle, $multi, $notice );
 677                 }
 678         }
 679
 680         /**
 681          * Get the diff table body, without header
 682          *
 683          * @return mixed (string/false)
 684          */
 685         public function getDiffBody() {
 686                 global $wgMemc;
 687                 wfProfileIn( __METHOD__ );
 688                 $this->mCacheHit = true;
 689                 // Check if the diff should be hidden from this user
 690                 if ( !$this->loadRevisionData() ) {
 691                         wfProfileOut( __METHOD__ );
 692                         return false;
 693                 } elseif ( $this->mOldRev && !$this->mOldRev->userCan( Revision::DELETED_TEXT ) ) {
 694                         wfProfileOut( __METHOD__ );
 695                         return false;
 696                 } elseif ( $this->mNewRev && !$this->mNewRev->userCan( Revision::DELETED_TEXT ) ) {
 697                         wfProfileOut( __METHOD__ );
 698                         return false;
 699                 }
 700                 // Short-circuit
 701                 if ( $this->mOldRev && $this->mNewRev
 702                         && $this->mOldRev->getID() == $this->mNewRev->getID() )
 703                 {
 704                         wfProfileOut( __METHOD__ );
 705                         return '';
 706                 }
 707                 // Cacheable?
 708                 $key = false;
 709                 if ( $this->mOldid && $this->mNewid ) {
 710                         $key = wfMemcKey( 'diff', 'version', MW_DIFF_VERSION,
 711                                 'oldid', $this->mOldid, 'newid', $this->mNewid );
 712                         // Try cache
 713                         if ( !$this->mRefreshCache ) {
 714                                 $difftext = $wgMemc->get( $key );
 715                                 if ( $difftext ) {
 716                                         wfIncrStats( 'diff_cache_hit' );
 717                                         $difftext = $this->localiseLineNumbers( $difftext );
 718                                         $difftext .= "\n<!-- diff cache key $key -->\n";
 719                                         wfProfileOut( __METHOD__ );
 720                                         return $difftext;
 721                                 }
 722                         } // don't try to load but save the result
 723                 }
 724                 $this->mCacheHit = false;
 725
 726                 // Loadtext is permission safe, this just clears out the diff
 727                 if ( !$this->loadText() ) {
 728                         wfProfileOut( __METHOD__ );
 729                         return false;
 730                 }
 731
 732                 $difftext = $this->generateDiffBody( $this->mOldtext, $this->mNewtext );
 733
 734                 // Save to cache for 7 days
 735                 if ( !wfRunHooks( 'AbortDiffCache', array( &$this ) ) ) {
 736                         wfIncrStats( 'diff_uncacheable' );
 737                 } elseif ( $key !== false && $difftext !== false ) {
 738                         wfIncrStats( 'diff_cache_miss' );
 739                         $wgMemc->set( $key, $difftext, 7 * 86400 );
 740                 } else {
 741                         wfIncrStats( 'diff_uncacheable' );
 742                 }
 743                 // Replace line numbers with the text in the user's language
 744                 if ( $difftext !== false ) {
 745                         $difftext = $this->localiseLineNumbers( $difftext );
 746                 }
 747                 wfProfileOut( __METHOD__ );
 748                 return $difftext;
 749         }
 750
 751         /**
 752          * Make sure the proper modules are loaded before we try to
 753          * make the diff
 754          */
 755         private function initDiffEngines() {
 756                 global $wgExternalDiffEngine;
 757                 if ( $wgExternalDiffEngine == 'wikidiff' && !function_exists( 'wikidiff_do_diff' ) ) {
 758                         wfProfileIn( __METHOD__ . '-php_wikidiff.so' );
 759                         wfDl( 'php_wikidiff' );
 760                         wfProfileOut( __METHOD__ . '-php_wikidiff.so' );
 761                 }
 762                 elseif ( $wgExternalDiffEngine == 'wikidiff2' && !function_exists( 'wikidiff2_do_diff' ) ) {
 763                         wfProfileIn( __METHOD__ . '-php_wikidiff2.so' );
 764                         wfDl( 'wikidiff2' );
 765                         wfProfileOut( __METHOD__ . '-php_wikidiff2.so' );
 766                 }
 767         }
 768
 769         /**
 770          * Generate a diff, no caching
 771          *
 772          * @param $otext String: old text, must be already segmented
 773          * @param $ntext String: new text, must be already segmented
 774          */
 775         function generateDiffBody( $otext, $ntext ) {
 776                 global $wgExternalDiffEngine, $wgContLang;
 777
 778                 wfProfileIn( __METHOD__ );
 779
 780                 $otext = str_replace( "\r\n", "\n", $otext );
 781                 $ntext = str_replace( "\r\n", "\n", $ntext );
 782
 783                 $this->initDiffEngines();
 784
 785                 if ( $wgExternalDiffEngine == 'wikidiff' && function_exists( 'wikidiff_do_diff' ) ) {
 786                         # For historical reasons, external diff engine expects
 787                         # input text to be HTML-escaped already
 788                         $otext = htmlspecialchars ( $wgContLang->segmentForDiff( $otext ) );
 789                         $ntext = htmlspecialchars ( $wgContLang->segmentForDiff( $ntext ) );
 790                         wfProfileOut( __METHOD__ );
 791                         return $wgContLang->unsegmentForDiff( wikidiff_do_diff( $otext, $ntext, 2 ) ) .
 792                         $this->debug( 'wikidiff1' );
 793                 }
 794
 795                 if ( $wgExternalDiffEngine == 'wikidiff2' && function_exists( 'wikidiff2_do_diff' ) ) {
 796                         # Better external diff engine, the 2 may some day be dropped
 797                         # This one does the escaping and segmenting itself
 798                         wfProfileIn( 'wikidiff2_do_diff' );
 799                         $text = wikidiff2_do_diff( $otext, $ntext, 2 );
 800                         $text .= $this->debug( 'wikidiff2' );
 801                         wfProfileOut( 'wikidiff2_do_diff' );
 802                         wfProfileOut( __METHOD__ );
 803                         return $text;
 804                 }
 805                 if ( $wgExternalDiffEngine != 'wikidiff3' && $wgExternalDiffEngine !== false ) {
 806                         # Diff via the shell
 807                         global $wgTmpDirectory;
 808                         $tempName1 = tempnam( $wgTmpDirectory, 'diff_' );
 809                         $tempName2 = tempnam( $wgTmpDirectory, 'diff_' );
 810
 811                         $tempFile1 = fopen( $tempName1, "w" );
 812                         if ( !$tempFile1 ) {
 813                                 wfProfileOut( __METHOD__ );
 814                                 return false;
 815                         }
 816                         $tempFile2 = fopen( $tempName2, "w" );
 817                         if ( !$tempFile2 ) {
 818                                 wfProfileOut( __METHOD__ );
 819                                 return false;
 820                         }
 821                         fwrite( $tempFile1, $otext );
 822                         fwrite( $tempFile2, $ntext );
 823                         fclose( $tempFile1 );
 824                         fclose( $tempFile2 );
 825                         $cmd = wfEscapeShellArg( $wgExternalDiffEngine, $tempName1, $tempName2 );
 826                         wfProfileIn( __METHOD__ . "-shellexec" );
 827                         $difftext = wfShellExec( $cmd );
 828                         $difftext .= $this->debug( "external $wgExternalDiffEngine" );
 829                         wfProfileOut( __METHOD__ . "-shellexec" );
 830                         unlink( $tempName1 );
 831                         unlink( $tempName2 );
 832                         wfProfileOut( __METHOD__ );
 833                         return $difftext;
 834                 }
 835
 836                 # Native PHP diff
 837                 $ota = explode( "\n", $wgContLang->segmentForDiff( $otext ) );
 838                 $nta = explode( "\n", $wgContLang->segmentForDiff( $ntext ) );
 839                 $diffs = new Diff( $ota, $nta );
 840                 $formatter = new TableDiffFormatter();
 841                 $difftext = $wgContLang->unsegmentForDiff( $formatter->format( $diffs ) ) .
 842                 wfProfileOut( __METHOD__ );
 843                 return $difftext;
 844         }
 845
 846         /**
 847          * Generate a debug comment indicating diff generating time,
 848          * server node, and generator backend.
 849          */
 850         protected function debug( $generator = "internal" ) {
 851                 global $wgShowHostnames;
 852                 if ( !$this->enableDebugComment ) {
 853                         return '';
 854                 }
 855                 $data = array( $generator );
 856                 if ( $wgShowHostnames ) {
 857                         $data[] = wfHostname();
 858                 }
 859                 $data[] = wfTimestamp( TS_DB );
 860                 return "<!-- diff generator: " .
 861                 implode( " ",
 862                 array_map(
 863                                         "htmlspecialchars",
 864                 $data ) ) .
 865                         " -->\n";
 866         }
 867
 868         /**
 869          * Replace line numbers with the text in the user's language
 870          */
 871         function localiseLineNumbers( $text ) {
 872                 return preg_replace_callback( '/<!--LINE (\d+)-->/',
 873                 array( &$this, 'localiseLineNumbersCb' ), $text );
 874         }
 875
 876         function localiseLineNumbersCb( $matches ) {
 877                 global $wgLang;
 878                 if ( $matches[1] === '1' && $this->mReducedLineNumbers ) return '';
 879                 return wfMsgExt( 'lineno', 'escape', $wgLang->formatNum( $matches[1] ) );
 880         }
 881
 882
 883         /**
 884          * If there are revisions between the ones being compared, return a note saying so.
 885          * @return string
 886          */
 887         function getMultiNotice() {
 888                 if ( !is_object( $this->mOldRev ) || !is_object( $this->mNewRev ) ) {
 889                         return '';
 890                 } elseif ( !$this->mOldPage->equals( $this->mNewPage ) ) {
 891                         // Comparing two different pages? Count would be meaningless.
 892                         return '';
 893                 }
 894
 895                 if ( $this->mOldRev->getTimestamp() > $this->mNewRev->getTimestamp() ) {
 896                         $oldRev = $this->mNewRev; // flip
 897                         $newRev = $this->mOldRev; // flip
 898                 } else { // normal case
 899                         $oldRev = $this->mOldRev;
 900                         $newRev = $this->mNewRev;
 901                 }
 902
 903                 $nEdits = $this->mTitle->countRevisionsBetween( $oldRev, $newRev );
 904                 if ( $nEdits > 0 ) {
 905                         $limit = 100; // use diff-multi-manyusers if too many users
 906                         $numUsers = $this->mTitle->countAuthorsBetween( $oldRev, $newRev, $limit );
 907                         return self::intermediateEditsMsg( $nEdits, $numUsers, $limit );
 908                 }
 909                 return ''; // nothing
 910         }
 911
 912         /**
 913          * Get a notice about how many intermediate edits and users there are
 914          * @param $numEdits int
 915          * @param $numUsers int
 916          * @param $limit int
 917          * @return string
 918          */
 919         public static function intermediateEditsMsg( $numEdits, $numUsers, $limit ) {
 920                 global $wgLang;
 921                 if ( $numUsers > $limit ) {
 922                         $msg = 'diff-multi-manyusers';
 923                         $numUsers = $limit;
 924                 } else {
 925                         $msg = 'diff-multi';
 926                 }
 927                 return wfMsgExt( $msg, 'parseinline',
 928                         $wgLang->formatnum( $numEdits ), $wgLang->formatnum( $numUsers ) );
 929         }
 930
 931         /**
 932          * Add the header to a diff body
 933          *
 934          * @return string
 935          */
 936         function addHeader( $diff, $otitle, $ntitle, $multi = '', $notice = '' ) {
 937                 // shared.css sets diff in interface language/dir, but the actual content
 938                 // is often in a different language, mostly the page content language/dir
 939                 $tableClass = 'diff diff-contentalign-' . htmlspecialchars( $this->mDiffLang->alignStart() );
 940                 $header = "<table class='$tableClass'>";
 941                 if ( $diff ) { // Safari/Chrome show broken output if cols not used
 942                         $header .= "
 943                         <col class='diff-marker' />
 944                         <col class='diff-content' />
 945                         <col class='diff-marker' />
 946                         <col class='diff-content' />";
 947                         $colspan = 2;
 948                         $multiColspan = 4;
 949                 } else {
 950                         $colspan = 1;
 951                         $multiColspan = 2;
 952                 }
 953                 $header .= "
 954                 <tr valign='top'>
 955                 <td colspan='$colspan' class='diff-otitle'>{$otitle}</td>
 956                 <td colspan='$colspan' class='diff-ntitle'>{$ntitle}</td>
 957                 </tr>";
 958
 959                 if ( $multi != '' ) {
 960                         $header .= "<tr><td colspan='{$multiColspan}' align='center' class='diff-multi'>{$multi}</td></tr>";
 961                 }
 962                 if ( $notice != '' ) {
 963                         $header .= "<tr><td colspan='{$multiColspan}' align='center'>{$notice}</td></tr>";
 964                 }
 965
 966                 return $header . $diff . "</table>";
 967         }
 968
 969         /**
 970          * Use specified text instead of loading from the database
 971          */
 972         function setText( $oldText, $newText ) {
 973                 $this->mOldtext = $oldText;
 974                 $this->mNewtext = $newText;
 975                 $this->mTextLoaded = 2;
 976                 $this->mRevisionsLoaded = true;
 977         }
 978
 979         /**
 980          * Set the language in which the diff text is written
 981          * (Defaults to page content language).
 982          * @since 1.19
 983          */
 984         function setDiffLang( $lang ) {
 985                 $this->mDiffLang = wfGetLangObj( $lang );
 986         }
 987
 988         /**
 989          * Load revision metadata for the specified articles. If newid is 0, then compare
 990          * the old article in oldid to the current article; if oldid is 0, then
 991          * compare the current article to the immediately previous one (ignoring the
 992          * value of newid).
 993          *
 994          * If oldid is false, leave the corresponding revision object set
 995          * to false. This is impossible via ordinary user input, and is provided for
 996          * API convenience.
 997          *
 998          * @return bool
 999          */
1000         function loadRevisionData() {
1001                 global $wgLang, $wgUser;
1002                 if ( $this->mRevisionsLoaded ) {
1003                         return true;
1004                 } else {
1005                         // Whether it succeeds or fails, we don't want to try again
1006                         $this->mRevisionsLoaded = true;
1007                 }
1008
1009                 // Load the new revision object
1010                 $this->mNewRev = $this->mNewid
1011                         ? Revision::newFromId( $this->mNewid )
1012                         : Revision::newFromTitle( $this->mTitle );
1013                 if ( !$this->mNewRev instanceof Revision ) {
1014                         return false;
1015                 }
1016
1017                 // Update the new revision ID in case it was 0 (makes life easier doing UI stuff)
1018                 $this->mNewid = $this->mNewRev->getId();
1019
1020                 // Check if page is editable
1021                 $editable = $this->mNewRev->getTitle()->userCan( 'edit' );
1022
1023                 // Set assorted variables
1024                 $timestamp = $wgLang->timeanddate( $this->mNewRev->getTimestamp(), true );
1025                 $dateofrev = $wgLang->date( $this->mNewRev->getTimestamp(), true );
1026                 $timeofrev = $wgLang->time( $this->mNewRev->getTimestamp(), true );
1027                 $this->mNewPage = $this->mNewRev->getTitle();
1028                 if ( $this->mNewRev->isCurrent() ) {
1029                         $newLink = $this->mNewPage->escapeLocalUrl( array(
1030                                 'oldid' => $this->mNewid
1031                         ) );
1032                         $this->mPagetitle = htmlspecialchars( wfMsg(
1033                                 'currentrev-asof',
1034                                 $timestamp,
1035                                 $dateofrev,
1036                                 $timeofrev
1037                         ) );
1038                         $newEdit = $this->mNewPage->escapeLocalUrl( array(
1039                                 'action' => 'edit'
1040                         ) );
1041
1042                         $this->mNewtitle = "<a href='$newLink'>{$this->mPagetitle}</a>";
1043                         $this->mNewtitle .= " (<a href='$newEdit'>" . wfMsgHtml( $editable ? 'editold' : 'viewsourceold' ) . "</a>)";
1044                 } else {
1045                         $newLink = $this->mNewPage->escapeLocalUrl( array(
1046                                 'oldid' => $this->mNewid
1047                         ) );
1048                         $newEdit = $this->mNewPage->escapeLocalUrl( array(
1049                                 'action' => 'edit',
1050                                 'oldid' => $this->mNewid
1051                         ) );
1052                         $this->mPagetitle = htmlspecialchars( wfMsg(
1053                                 'revisionasof',
1054                                 $timestamp,
1055                                 $dateofrev,
1056                                 $timeofrev
1057                         ) );
1058
1059                         $this->mNewtitle = "<a href='$newLink'>{$this->mPagetitle}</a>";
1060                         $this->mNewtitle .= " (<a href='$newEdit'>" . wfMsgHtml( $editable ? 'editold' : 'viewsourceold' ) . "</a>)";
1061                 }
1062                 if ( !$this->mNewRev->userCan( Revision::DELETED_TEXT ) ) {
1063                         $this->mNewtitle = "<span class='history-deleted'>{$this->mPagetitle}</span>";
1064                 } elseif ( $this->mNewRev->isDeleted( Revision::DELETED_TEXT ) ) {
1065                         $this->mNewtitle = "<span class='history-deleted'>{$this->mNewtitle}</span>";
1066                 }
1067
1068                 // Load the old revision object
1069                 $this->mOldRev = false;
1070                 if ( $this->mOldid ) {
1071                         $this->mOldRev = Revision::newFromId( $this->mOldid );
1072                 } elseif ( $this->mOldid === 0 ) {
1073                         $rev = $this->mNewRev->getPrevious();
1074                         if ( $rev ) {
1075                                 $this->mOldid = $rev->getId();
1076                                 $this->mOldRev = $rev;
1077                         } else {
1078                                 // No previous revision; mark to show as first-version only.
1079                                 $this->mOldid = false;
1080                                 $this->mOldRev = false;
1081                         }
1082                 } /* elseif ( $this->mOldid === false ) leave mOldRev false; */
1083
1084                 if ( is_null( $this->mOldRev ) ) {
1085                         return false;
1086                 }
1087
1088                 if ( $this->mOldRev ) {
1089                         $this->mOldPage = $this->mOldRev->getTitle();
1090
1091                         $t = $wgLang->timeanddate( $this->mOldRev->getTimestamp(), true );
1092                         $dateofrev = $wgLang->date( $this->mOldRev->getTimestamp(), true );
1093                         $timeofrev = $wgLang->time( $this->mOldRev->getTimestamp(), true );
1094                         $oldLink = $this->mOldPage->escapeLocalUrl( array(
1095                                 'oldid' => $this->mOldid
1096                         ) );
1097                         $oldEdit = $this->mOldPage->escapeLocalUrl( array(
1098                                 'action' => 'edit',
1099                                 'oldid' => $this->mOldid
1100                         ) );
1101                         $this->mOldPagetitle = htmlspecialchars( wfMsg( 'revisionasof', $t, $dateofrev, $timeofrev ) );
1102
1103                         $this->mOldtitle = "<a href='$oldLink'>{$this->mOldPagetitle}</a>"
1104                         . " (<a href='$oldEdit'>" . wfMsgHtml( $editable ? 'editold' : 'viewsourceold' ) . "</a>)";
1105                         // Add an "undo" link
1106                         if ( $editable && !$this->mOldRev->isDeleted( Revision::DELETED_TEXT ) && !$this->mNewRev->isDeleted( Revision::DELETED_TEXT ) ) {
1107                                 $undoLink = Html::element( 'a', array(
1108                                         'href' => $this->mNewPage->getLocalUrl( array(
1109                                                 'action' => 'edit',
1110                                                 'undoafter' => $this->mOldid,
1111                                                 'undo' => $this->mNewid ) ),
1112                                         'title' => $wgUser->getSkin()->titleAttrib( 'undo' )
1113                                 ), wfMsg( 'editundo' ) );
1114                                 $this->mNewtitle .= ' (' . $undoLink . ')';
1115                         }
1116
1117                         if ( !$this->mOldRev->userCan( Revision::DELETED_TEXT ) ) {
1118                                 $this->mOldtitle = '<span class="history-deleted">' . $this->mOldPagetitle . '</span>';
1119                         } elseif ( $this->mOldRev->isDeleted( Revision::DELETED_TEXT ) ) {
1120                                 $this->mOldtitle = '<span class="history-deleted">' . $this->mOldtitle . '</span>';
1121                         }
1122                 }
1123
1124                 return true;
1125         }
1126
1127         /**
1128          * Load the text of the revisions, as well as revision data.
1129          *
1130          * @return bool
1131          */
1132         function loadText() {
1133                 if ( $this->mTextLoaded == 2 ) {
1134                         return true;
1135                 } else {
1136                         // Whether it succeeds or fails, we don't want to try again
1137                         $this->mTextLoaded = 2;
1138                 }
1139
1140                 if ( !$this->loadRevisionData() ) {
1141                         return false;
1142                 }
1143                 if ( $this->mOldRev ) {
1144                         $this->mOldtext = $this->mOldRev->getText( Revision::FOR_THIS_USER );
1145                         if ( $this->mOldtext === false ) {
1146                                 return false;
1147                         }
1148                 }
1149                 if ( $this->mNewRev ) {
1150                         $this->mNewtext = $this->mNewRev->getText( Revision::FOR_THIS_USER );
1151                         if ( $this->mNewtext === false ) {
1152                                 return false;
1153                         }
1154                 }
1155                 return true;
1156         }
1157
1158         /**
1159          * Load the text of the new revision, not the old one
1160          *
1161          * @return bool
1162          */
1163         function loadNewText() {
1164                 if ( $this->mTextLoaded >= 1 ) {
1165                         return true;
1166                 } else {
1167                         $this->mTextLoaded = 1;
1168                 }
1169                 if ( !$this->loadRevisionData() ) {
1170                         return false;
1171                 }
1172                 $this->mNewtext = $this->mNewRev->getText( Revision::FOR_THIS_USER );
1173                 return true;
1174         }
1175 }