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                 $wgOut->addHTML( "<hr class='diff-hr' />
 510                 <h2 class='diff-currentversion-title'>{$this->mPagetitle}</h2>\n" );
 511                 # Page content may be handled by a hooked call instead...
 512                 if ( wfRunHooks( 'ArticleContentOnDiff', array( $this, $wgOut ) ) ) {
 513                         # Use the current version parser cache if applicable
 514                         $pCache = true;
 515                         if ( !$this->mNewRev->isCurrent() ) {
 516                                 $oldEditSectionSetting = $wgOut->parserOptions()->setEditSection( false );
 517                                 $pCache = false;
 518                         }
 519
 520                         $this->loadNewText();
 521                         $wgOut->setRevisionId( $this->mNewRev->getId() );
 522
 523                         if ( $this->mTitle->isCssJsSubpage() || $this->mTitle->isCssOrJsPage() ) {
 524                                 // Stolen from Article::view --AG 2007-10-11
 525                                 // Give hooks a chance to customise the output
 526                                 // @TODO: standardize this crap into one function
 527                                 if ( wfRunHooks( 'ShowRawCssJs', array( $this->mNewtext, $this->mTitle, $wgOut ) ) ) {
 528                                         // Wrap the whole lot in a <pre> and don't parse
 529                                         $m = array();
 530                                         preg_match( '!\.(css|js)$!u', $this->mTitle->getText(), $m );
 531                                         $wgOut->addHTML( "<pre class=\"mw-code mw-{$m[1]}\" dir=\"ltr\">\n" );
 532                                         $wgOut->addHTML( htmlspecialchars( $this->mNewtext ) );
 533                                         $wgOut->addHTML( "\n</pre>\n" );
 534                                 }
 535                         } elseif ( $pCache ) {
 536                                 $article = new Article( $this->mTitle, 0 );
 537                                 $pOutput = ParserCache::singleton()->get( $article, $wgOut->parserOptions() );
 538                                 if( $pOutput ) {
 539                                         $wgOut->addParserOutput( $pOutput );
 540                                 } else {
 541                                         $article->doViewParse();
 542                                 }
 543                         } else {
 544                                 $wgOut->addWikiTextTidy( $this->mNewtext );
 545                         }
 546
 547                         if ( !$this->mNewRev->isCurrent() ) {
 548                                 $wgOut->parserOptions()->setEditSection( $oldEditSectionSetting );
 549                         }
 550                 }
 551                 # Add redundant patrol link on bottom...
 552                 if ( $this->mRcidMarkPatrolled && $this->mTitle->quickUserCan( 'patrol' ) ) {
 553                         $sk = $wgUser->getSkin();
 554                         $token = $wgUser->editToken( $this->mRcidMarkPatrolled );
 555                         $wgOut->preventClickjacking();
 556                         $wgOut->addHTML(
 557                                 "<div class='patrollink'>[" . $sk->link(
 558                                         $this->mTitle,
 559                                         wfMsgHtml( 'markaspatrolleddiff' ),
 560                                         array(),
 561                                         array(
 562                                                 'action'        => 'markpatrolled',
 563                                                 'rcid'          => $this->mRcidMarkPatrolled,
 564                                                 'token'         => $token,
 565                                         )
 566                                 ) . ']</div>'
 567                          );
 568                 }
 569
 570                 wfProfileOut( __METHOD__ );
 571         }
 572
 573         /**
 574          * Show the first revision of an article. Uses normal diff headers in
 575          * contrast to normal "old revision" display style.
 576          */
 577         function showFirstRevision() {
 578                 global $wgOut, $wgUser;
 579                 wfProfileIn( __METHOD__ );
 580
 581                 # Get article text from the DB
 582                 #
 583                 if ( ! $this->loadNewText() ) {
 584                         $t = $this->mTitle->getPrefixedText();
 585                         $d = wfMsgExt( 'missingarticle-diff', array( 'escape' ),
 586                                         $this->deletedIdMarker( $this->mOldid ),
 587                                         $this->deletedIdMarker( $this->mNewid ) );
 588                         $wgOut->setPagetitle( wfMsg( 'errorpagetitle' ) );
 589                         $wgOut->addWikiMsg( 'missing-article', "<nowiki>$t</nowiki>", "<span class='plainlinks'>$d</span>" );
 590                         wfProfileOut( __METHOD__ );
 591                         return;
 592                 }
 593                 if ( $this->mNewRev->isCurrent() ) {
 594                         $wgOut->setArticleFlag( true );
 595                 }
 596
 597                 # Check if user is allowed to look at this page. If not, bail out.
 598                 #
 599                 if ( !$this->mTitle->userCanRead() ) {
 600                         $wgOut->loginToUse();
 601                         $wgOut->output();
 602                         wfProfileOut( __METHOD__ );
 603                         throw new MWException( "Permission Error: you do not have access to view this page" );
 604                 }
 605
 606                 # Prepare the header box
 607                 #
 608                 $sk = $wgUser->getSkin();
 609
 610                 $next = $this->mTitle->getNextRevisionID( $this->mNewid );
 611                 if ( !$next ) {
 612                         $nextlink = '';
 613                 } else {
 614                         $nextlink = '<br />' . $sk->link(
 615                                 $this->mTitle,
 616                                 wfMsgHtml( 'nextdiff' ),
 617                                 array(
 618                                         'id' => 'differences-nextlink'
 619                                 ),
 620                                 array(
 621                                         'diff' => 'next',
 622                                         'oldid' => $this->mNewid,
 623                                 ),
 624                                 array(
 625                                         'known',
 626                                         'noclasses'
 627                                 )
 628                         );
 629                 }
 630                 $header = "<div class=\"firstrevisionheader\" style=\"text-align: center\">" .
 631                         $sk->revUserTools( $this->mNewRev ) . "<br />" . $sk->revComment( $this->mNewRev ) . $nextlink . "</div>\n";
 632
 633                 $wgOut->addHTML( $header );
 634
 635                 $wgOut->setSubtitle( wfMsgExt( 'difference', array( 'parseinline' ) ) );
 636                 $wgOut->setRobotPolicy( 'noindex,nofollow' );
 637
 638                 wfProfileOut( __METHOD__ );
 639         }
 640
 641         /**
 642          * Get the diff text, send it to $wgOut
 643          * Returns false if the diff could not be generated, otherwise returns true
 644          *
 645          * @return bool
 646          */
 647         function showDiff( $otitle, $ntitle, $notice = '' ) {
 648                 global $wgOut;
 649                 $diff = $this->getDiff( $otitle, $ntitle, $notice );
 650                 if ( $diff === false ) {
 651                         $wgOut->addWikiMsg( 'missing-article', "<nowiki>(fixme, bug)</nowiki>", '' );
 652                         return false;
 653                 } else {
 654                         $this->showDiffStyle();
 655                         $wgOut->addHTML( $diff );
 656                         return true;
 657                 }
 658         }
 659
 660         /**
 661          * Add style sheets and supporting JS for diff display.
 662          */
 663         function showDiffStyle() {
 664                 global $wgOut;
 665                 $wgOut->addModuleStyles( 'mediawiki.legacy.diff' );
 666         }
 667
 668         /**
 669          * Get complete diff table, including header
 670          *
 671          * @param $otitle Title: old title
 672          * @param $ntitle Title: new title
 673          * @param $notice String: HTML between diff header and body
 674          * @return mixed
 675          */
 676         function getDiff( $otitle, $ntitle, $notice = '' ) {
 677                 $body = $this->getDiffBody();
 678                 if ( $body === false ) {
 679                         return false;
 680                 } else {
 681                         $multi = $this->getMultiNotice();
 682                         return $this->addHeader( $body, $otitle, $ntitle, $multi, $notice );
 683                 }
 684         }
 685
 686         /**
 687          * Get the diff table body, without header
 688          *
 689          * @return mixed (string/false)
 690          */
 691         public function getDiffBody() {
 692                 global $wgMemc;
 693                 wfProfileIn( __METHOD__ );
 694                 $this->mCacheHit = true;
 695                 // Check if the diff should be hidden from this user
 696                 if ( !$this->loadRevisionData() ) {
 697                         wfProfileOut( __METHOD__ );
 698                         return false;
 699                 } elseif ( $this->mOldRev && !$this->mOldRev->userCan( Revision::DELETED_TEXT ) ) {
 700                         wfProfileOut( __METHOD__ );
 701                         return false;
 702                 } elseif ( $this->mNewRev && !$this->mNewRev->userCan( Revision::DELETED_TEXT ) ) {
 703                         wfProfileOut( __METHOD__ );
 704                         return false;
 705                 }
 706                 // Short-circuit
 707                 if ( $this->mOldRev && $this->mNewRev
 708                         && $this->mOldRev->getID() == $this->mNewRev->getID() )
 709                 {
 710                         wfProfileOut( __METHOD__ );
 711                         return '';
 712                 }
 713                 // Cacheable?
 714                 $key = false;
 715                 if ( $this->mOldid && $this->mNewid ) {
 716                         $key = wfMemcKey( 'diff', 'version', MW_DIFF_VERSION,
 717                                 'oldid', $this->mOldid, 'newid', $this->mNewid );
 718                         // Try cache
 719                         if ( !$this->mRefreshCache ) {
 720                                 $difftext = $wgMemc->get( $key );
 721                                 if ( $difftext ) {
 722                                         wfIncrStats( 'diff_cache_hit' );
 723                                         $difftext = $this->localiseLineNumbers( $difftext );
 724                                         $difftext .= "\n<!-- diff cache key $key -->\n";
 725                                         wfProfileOut( __METHOD__ );
 726                                         return $difftext;
 727                                 }
 728                         } // don't try to load but save the result
 729                 }
 730                 $this->mCacheHit = false;
 731
 732                 // Loadtext is permission safe, this just clears out the diff
 733                 if ( !$this->loadText() ) {
 734                         wfProfileOut( __METHOD__ );
 735                         return false;
 736                 }
 737
 738                 $difftext = $this->generateDiffBody( $this->mOldtext, $this->mNewtext );
 739
 740                 // Save to cache for 7 days
 741                 if ( !wfRunHooks( 'AbortDiffCache', array( &$this ) ) ) {
 742                         wfIncrStats( 'diff_uncacheable' );
 743                 } elseif ( $key !== false && $difftext !== false ) {
 744                         wfIncrStats( 'diff_cache_miss' );
 745                         $wgMemc->set( $key, $difftext, 7 * 86400 );
 746                 } else {
 747                         wfIncrStats( 'diff_uncacheable' );
 748                 }
 749                 // Replace line numbers with the text in the user's language
 750                 if ( $difftext !== false ) {
 751                         $difftext = $this->localiseLineNumbers( $difftext );
 752                 }
 753                 wfProfileOut( __METHOD__ );
 754                 return $difftext;
 755         }
 756
 757         /**
 758          * Make sure the proper modules are loaded before we try to
 759          * make the diff
 760          */
 761         private function initDiffEngines() {
 762                 global $wgExternalDiffEngine;
 763                 if ( $wgExternalDiffEngine == 'wikidiff' && !function_exists( 'wikidiff_do_diff' ) ) {
 764                         wfProfileIn( __METHOD__ . '-php_wikidiff.so' );
 765                         wfDl( 'php_wikidiff' );
 766                         wfProfileOut( __METHOD__ . '-php_wikidiff.so' );
 767                 }
 768                 elseif ( $wgExternalDiffEngine == 'wikidiff2' && !function_exists( 'wikidiff2_do_diff' ) ) {
 769                         wfProfileIn( __METHOD__ . '-php_wikidiff2.so' );
 770                         wfDl( 'wikidiff2' );
 771                         wfProfileOut( __METHOD__ . '-php_wikidiff2.so' );
 772                 }
 773         }
 774
 775         /**
 776          * Generate a diff, no caching
 777          *
 778          * @param $otext String: old text, must be already segmented
 779          * @param $ntext String: new text, must be already segmented
 780          */
 781         function generateDiffBody( $otext, $ntext ) {
 782                 global $wgExternalDiffEngine, $wgContLang;
 783
 784                 $otext = str_replace( "\r\n", "\n", $otext );
 785                 $ntext = str_replace( "\r\n", "\n", $ntext );
 786
 787                 $this->initDiffEngines();
 788
 789                 if ( $wgExternalDiffEngine == 'wikidiff' && function_exists( 'wikidiff_do_diff' ) ) {
 790                         # For historical reasons, external diff engine expects
 791                         # input text to be HTML-escaped already
 792                         $otext = htmlspecialchars ( $wgContLang->segmentForDiff( $otext ) );
 793                         $ntext = htmlspecialchars ( $wgContLang->segmentForDiff( $ntext ) );
 794                         return $wgContLang->unsegmentForDiff( wikidiff_do_diff( $otext, $ntext, 2 ) ) .
 795                         $this->debug( 'wikidiff1' );
 796                 }
 797
 798                 if ( $wgExternalDiffEngine == 'wikidiff2' && function_exists( 'wikidiff2_do_diff' ) ) {
 799                         # Better external diff engine, the 2 may some day be dropped
 800                         # This one does the escaping and segmenting itself
 801                         wfProfileIn( 'wikidiff2_do_diff' );
 802                         $text = wikidiff2_do_diff( $otext, $ntext, 2 );
 803                         $text .= $this->debug( 'wikidiff2' );
 804                         wfProfileOut( 'wikidiff2_do_diff' );
 805                         return $text;
 806                 }
 807                 if ( $wgExternalDiffEngine != 'wikidiff3' && $wgExternalDiffEngine !== false ) {
 808                         # Diff via the shell
 809                         global $wgTmpDirectory;
 810                         $tempName1 = tempnam( $wgTmpDirectory, 'diff_' );
 811                         $tempName2 = tempnam( $wgTmpDirectory, 'diff_' );
 812
 813                         $tempFile1 = fopen( $tempName1, "w" );
 814                         if ( !$tempFile1 ) {
 815                                 wfProfileOut( __METHOD__ );
 816                                 return false;
 817                         }
 818                         $tempFile2 = fopen( $tempName2, "w" );
 819                         if ( !$tempFile2 ) {
 820                                 wfProfileOut( __METHOD__ );
 821                                 return false;
 822                         }
 823                         fwrite( $tempFile1, $otext );
 824                         fwrite( $tempFile2, $ntext );
 825                         fclose( $tempFile1 );
 826                         fclose( $tempFile2 );
 827                         $cmd = wfEscapeShellArg( $wgExternalDiffEngine, $tempName1, $tempName2 );
 828                         wfProfileIn( __METHOD__ . "-shellexec" );
 829                         $difftext = wfShellExec( $cmd );
 830                         $difftext .= $this->debug( "external $wgExternalDiffEngine" );
 831                         wfProfileOut( __METHOD__ . "-shellexec" );
 832                         unlink( $tempName1 );
 833                         unlink( $tempName2 );
 834                         wfProfileOut( __METHOD__ );
 835                         return $difftext;
 836                 }
 837
 838                 # Native PHP diff
 839                 $ota = explode( "\n", $wgContLang->segmentForDiff( $otext ) );
 840                 $nta = explode( "\n", $wgContLang->segmentForDiff( $ntext ) );
 841                 $diffs = new Diff( $ota, $nta );
 842                 $formatter = new TableDiffFormatter();
 843                 $difftext = $wgContLang->unsegmentForDiff( $formatter->format( $diffs ) ) .
 844                 wfProfileOut( __METHOD__ );
 845                 return $difftext;
 846         }
 847
 848         /**
 849          * Generate a debug comment indicating diff generating time,
 850          * server node, and generator backend.
 851          */
 852         protected function debug( $generator = "internal" ) {
 853                 global $wgShowHostnames;
 854                 if ( !$this->enableDebugComment ) {
 855                         return '';
 856                 }
 857                 $data = array( $generator );
 858                 if ( $wgShowHostnames ) {
 859                         $data[] = wfHostname();
 860                 }
 861                 $data[] = wfTimestamp( TS_DB );
 862                 return "<!-- diff generator: " .
 863                 implode( " ",
 864                 array_map(
 865                                         "htmlspecialchars",
 866                 $data ) ) .
 867                         " -->\n";
 868         }
 869
 870         /**
 871          * Replace line numbers with the text in the user's language
 872          */
 873         function localiseLineNumbers( $text ) {
 874                 return preg_replace_callback( '/<!--LINE (\d+)-->/',
 875                 array( &$this, 'localiseLineNumbersCb' ), $text );
 876         }
 877
 878         function localiseLineNumbersCb( $matches ) {
 879                 global $wgLang;
 880                 if ( $matches[1] === '1' && $this->mReducedLineNumbers ) return '';
 881                 return wfMsgExt( 'lineno', 'escape', $wgLang->formatNum( $matches[1] ) );
 882         }
 883
 884
 885         /**
 886          * If there are revisions between the ones being compared, return a note saying so.
 887          * @return string
 888          */
 889         function getMultiNotice() {
 890                 if ( !is_object( $this->mOldRev ) || !is_object( $this->mNewRev ) ) {
 891                         return '';
 892                 } elseif ( !$this->mOldPage->equals( $this->mNewPage ) ) {
 893                         // Comparing two different pages? Count would be meaningless.
 894                         return '';
 895                 }
 896
 897                 if ( $this->mOldRev->getTimestamp() > $this->mNewRev->getTimestamp() ) {
 898                         $oldRev = $this->mNewRev; // flip
 899                         $newRev = $this->mOldRev; // flip
 900                 } else { // normal case
 901                         $oldRev = $this->mOldRev;
 902                         $newRev = $this->mNewRev;
 903                 }
 904
 905                 $nEdits = $this->mTitle->countRevisionsBetween( $oldRev, $newRev );
 906                 if ( $nEdits > 0 ) {
 907                         $limit = 100; // use diff-multi-manyusers if too many users
 908                         $numUsers = $this->mTitle->countAuthorsBetween( $oldRev, $newRev, $limit );
 909                         return self::intermediateEditsMsg( $nEdits, $numUsers, $limit );
 910                 }
 911                 return ''; // nothing
 912         }
 913
 914         /**
 915          * Get a notice about how many intermediate edits and users there are
 916          * @param $numEdits int
 917          * @param $numUsers int
 918          * @param $limit int
 919          * @return string
 920          */
 921         public static function intermediateEditsMsg( $numEdits, $numUsers, $limit ) {
 922                 global $wgLang;
 923                 if ( $numUsers > $limit ) {
 924                         $msg = 'diff-multi-manyusers';
 925                         $numUsers = $limit;
 926                 } else {
 927                         $msg = 'diff-multi';
 928                 }
 929                 return wfMsgExt( $msg, 'parseinline',
 930                         $wgLang->formatnum( $numEdits ), $wgLang->formatnum( $numUsers ) );
 931         }
 932
 933         /**
 934          * Add the header to a diff body
 935          *
 936          * @return string
 937          */
 938         static function addHeader( $diff, $otitle, $ntitle, $multi = '', $notice = '' ) {
 939                 global $wgBetterDirectionality, $wgTitle;
 940                 $dirclass = '';
 941                 if( $wgBetterDirectionality ) {
 942                         // shared.css sets diff in interface language/dir,
 943                         // but the actual content should be in the page language/dir
 944                         $pageLang = $wgTitle->getPageLanguage();
 945                         $dirclass = ' diff-contentalign-'.$pageLang->alignStart();
 946                 }
 947                 $header = "<table class='diff $dirclass'>";
 948                 if ( $diff ) { // Safari/Chrome show broken output if cols not used
 949                         $header .= "
 950                         <col class='diff-marker' />
 951                         <col class='diff-content' />
 952                         <col class='diff-marker' />
 953                         <col class='diff-content' />";
 954                         $colspan = 2;
 955                         $multiColspan = 4;
 956                 } else {
 957                         $colspan = 1;
 958                         $multiColspan = 2;
 959                 }
 960                 $header .= "
 961                 <tr valign='top'>
 962                 <td colspan='$colspan' class='diff-otitle'>{$otitle}</td>
 963                 <td colspan='$colspan' class='diff-ntitle'>{$ntitle}</td>
 964                 </tr>";
 965
 966                 if ( $multi != '' ) {
 967                         $header .= "<tr><td colspan='{$multiColspan}' align='center' class='diff-multi'>{$multi}</td></tr>";
 968                 }
 969                 if ( $notice != '' ) {
 970                         $header .= "<tr><td colspan='{$multiColspan}' align='center'>{$notice}</td></tr>";
 971                 }
 972
 973                 return $header . $diff . "</table>";
 974         }
 975
 976         /**
 977          * Use specified text instead of loading from the database
 978          */
 979         function setText( $oldText, $newText ) {
 980                 $this->mOldtext = $oldText;
 981                 $this->mNewtext = $newText;
 982                 $this->mTextLoaded = 2;
 983                 $this->mRevisionsLoaded = true;
 984         }
 985
 986         /**
 987          * Load revision metadata for the specified articles. If newid is 0, then compare
 988          * the old article in oldid to the current article; if oldid is 0, then
 989          * compare the current article to the immediately previous one (ignoring the
 990          * value of newid).
 991          *
 992          * If oldid is false, leave the corresponding revision object set
 993          * to false. This is impossible via ordinary user input, and is provided for
 994          * API convenience.
 995          *
 996          * @return bool
 997          */
 998         function loadRevisionData() {
 999                 global $wgLang, $wgUser;
1000                 if ( $this->mRevisionsLoaded ) {
1001                         return true;
1002                 } else {
1003                         // Whether it succeeds or fails, we don't want to try again
1004                         $this->mRevisionsLoaded = true;
1005                 }
1006
1007                 // Load the new revision object
1008                 $this->mNewRev = $this->mNewid
1009                         ? Revision::newFromId( $this->mNewid )
1010                         : Revision::newFromTitle( $this->mTitle );
1011                 if ( !$this->mNewRev instanceof Revision ) {
1012                         return false;
1013                 }
1014
1015                 // Update the new revision ID in case it was 0 (makes life easier doing UI stuff)
1016                 $this->mNewid = $this->mNewRev->getId();
1017
1018                 // Check if page is editable
1019                 $editable = $this->mNewRev->getTitle()->userCan( 'edit' );
1020
1021                 // Set assorted variables
1022                 $timestamp = $wgLang->timeanddate( $this->mNewRev->getTimestamp(), true );
1023                 $dateofrev = $wgLang->date( $this->mNewRev->getTimestamp(), true );
1024                 $timeofrev = $wgLang->time( $this->mNewRev->getTimestamp(), true );
1025                 $this->mNewPage = $this->mNewRev->getTitle();
1026                 if ( $this->mNewRev->isCurrent() ) {
1027                         $newLink = $this->mNewPage->escapeLocalUrl( array(
1028                                 'oldid' => $this->mNewid
1029                         ) );
1030                         $this->mPagetitle = htmlspecialchars( wfMsg(
1031                                 'currentrev-asof',
1032                                 $timestamp,
1033                                 $dateofrev,
1034                                 $timeofrev
1035                         ) );
1036                         $newEdit = $this->mNewPage->escapeLocalUrl( array(
1037                                 'action' => 'edit'
1038                         ) );
1039
1040                         $this->mNewtitle = "<a href='$newLink'>{$this->mPagetitle}</a>";
1041                         $this->mNewtitle .= " (<a href='$newEdit'>" . wfMsgHtml( $editable ? 'editold' : 'viewsourceold' ) . "</a>)";
1042                 } else {
1043                         $newLink = $this->mNewPage->escapeLocalUrl( array(
1044                                 'oldid' => $this->mNewid
1045                         ) );
1046                         $newEdit = $this->mNewPage->escapeLocalUrl( array(
1047                                 'action' => 'edit',
1048                                 'oldid' => $this->mNewid
1049                         ) );
1050                         $this->mPagetitle = htmlspecialchars( wfMsg(
1051                                 'revisionasof',
1052                                 $timestamp,
1053                                 $dateofrev,
1054                                 $timeofrev
1055                         ) );
1056
1057                         $this->mNewtitle = "<a href='$newLink'>{$this->mPagetitle}</a>";
1058                         $this->mNewtitle .= " (<a href='$newEdit'>" . wfMsgHtml( $editable ? 'editold' : 'viewsourceold' ) . "</a>)";
1059                 }
1060                 if ( !$this->mNewRev->userCan( Revision::DELETED_TEXT ) ) {
1061                         $this->mNewtitle = "<span class='history-deleted'>{$this->mPagetitle}</span>";
1062                 } elseif ( $this->mNewRev->isDeleted( Revision::DELETED_TEXT ) ) {
1063                         $this->mNewtitle = "<span class='history-deleted'>{$this->mNewtitle}</span>";
1064                 }
1065
1066                 // Load the old revision object
1067                 $this->mOldRev = false;
1068                 if ( $this->mOldid ) {
1069                         $this->mOldRev = Revision::newFromId( $this->mOldid );
1070                 } elseif ( $this->mOldid === 0 ) {
1071                         $rev = $this->mNewRev->getPrevious();
1072                         if ( $rev ) {
1073                                 $this->mOldid = $rev->getId();
1074                                 $this->mOldRev = $rev;
1075                         } else {
1076                                 // No previous revision; mark to show as first-version only.
1077                                 $this->mOldid = false;
1078                                 $this->mOldRev = false;
1079                         }
1080                 } /* elseif ( $this->mOldid === false ) leave mOldRev false; */
1081
1082                 if ( is_null( $this->mOldRev ) ) {
1083                         return false;
1084                 }
1085
1086                 if ( $this->mOldRev ) {
1087                         $this->mOldPage = $this->mOldRev->getTitle();
1088
1089                         $t = $wgLang->timeanddate( $this->mOldRev->getTimestamp(), true );
1090                         $dateofrev = $wgLang->date( $this->mOldRev->getTimestamp(), true );
1091                         $timeofrev = $wgLang->time( $this->mOldRev->getTimestamp(), true );
1092                         $oldLink = $this->mOldPage->escapeLocalUrl( array(
1093                                 'oldid' => $this->mOldid
1094                         ) );
1095                         $oldEdit = $this->mOldPage->escapeLocalUrl( array(
1096                                 'action' => 'edit',
1097                                 'oldid' => $this->mOldid
1098                         ) );
1099                         $this->mOldPagetitle = htmlspecialchars( wfMsg( 'revisionasof', $t, $dateofrev, $timeofrev ) );
1100
1101                         $this->mOldtitle = "<a href='$oldLink'>{$this->mOldPagetitle}</a>"
1102                         . " (<a href='$oldEdit'>" . wfMsgHtml( $editable ? 'editold' : 'viewsourceold' ) . "</a>)";
1103                         // Add an "undo" link
1104                         if ( $editable && !$this->mOldRev->isDeleted( Revision::DELETED_TEXT ) && !$this->mNewRev->isDeleted( Revision::DELETED_TEXT ) ) {
1105                                 $undoLink = Html::element( 'a', array(
1106                                         'href' => $this->mNewPage->getLocalUrl( array(
1107                                                 'action' => 'edit',
1108                                                 'undoafter' => $this->mOldid,
1109                                                 'undo' => $this->mNewid ) ),
1110                                         'title' => $wgUser->getSkin()->titleAttrib( 'undo' )
1111                                 ), wfMsg( 'editundo' ) );
1112                                 $this->mNewtitle .= ' (' . $undoLink . ')';
1113                         }
1114
1115                         if ( !$this->mOldRev->userCan( Revision::DELETED_TEXT ) ) {
1116                                 $this->mOldtitle = '<span class="history-deleted">' . $this->mOldPagetitle . '</span>';
1117                         } elseif ( $this->mOldRev->isDeleted( Revision::DELETED_TEXT ) ) {
1118                                 $this->mOldtitle = '<span class="history-deleted">' . $this->mOldtitle . '</span>';
1119                         }
1120                 }
1121
1122                 return true;
1123         }
1124
1125         /**
1126          * Load the text of the revisions, as well as revision data.
1127          *
1128          * @return bool
1129          */
1130         function loadText() {
1131                 if ( $this->mTextLoaded == 2 ) {
1132                         return true;
1133                 } else {
1134                         // Whether it succeeds or fails, we don't want to try again
1135                         $this->mTextLoaded = 2;
1136                 }
1137
1138                 if ( !$this->loadRevisionData() ) {
1139                         return false;
1140                 }
1141                 if ( $this->mOldRev ) {
1142                         $this->mOldtext = $this->mOldRev->getText( Revision::FOR_THIS_USER );
1143                         if ( $this->mOldtext === false ) {
1144                                 return false;
1145                         }
1146                 }
1147                 if ( $this->mNewRev ) {
1148                         $this->mNewtext = $this->mNewRev->getText( Revision::FOR_THIS_USER );
1149                         if ( $this->mNewtext === false ) {
1150                                 return false;
1151                         }
1152                 }
1153                 return true;
1154         }
1155
1156         /**
1157          * Load the text of the new revision, not the old one
1158          *
1159          * @return bool
1160          */
1161         function loadNewText() {
1162                 if ( $this->mTextLoaded >= 1 ) {
1163                         return true;
1164                 } else {
1165                         $this->mTextLoaded = 1;
1166                 }
1167                 if ( !$this->loadRevisionData() ) {
1168                         return false;
1169                 }
1170                 $this->mNewtext = $this->mNewRev->getText( Revision::FOR_THIS_USER );
1171                 return true;
1172         }
1173 }