includes/PageHistory.php

   1 <?php
   2 /**
   3  * Page history
   4  *
   5  * Split off from Article.php and Skin.php, 2003-12-22
   6  */
   7
   8 /**
   9  * This class handles printing the history page for an article.  In order to
  10  * be efficient, it uses timestamps rather than offsets for paging, to avoid
  11  * costly LIMIT,offset queries.
  12  *
  13  * Construct it by passing in an Article, and call $h->history() to print the
  14  * history.
  15  *
  16  */
  17 class PageHistory {
  18         const DIR_PREV = 0;
  19         const DIR_NEXT = 1;
  20
  21         var $mArticle, $mTitle, $mSkin;
  22         var $lastdate;
  23         var $linesonpage;
  24         var $mNotificationTimestamp;
  25         var $mLatestId = null;
  26
  27         /**
  28          * Construct a new PageHistory.
  29          *
  30          * @param Article $article
  31          * @returns nothing
  32          */
  33         function __construct($article) {
  34                 global $wgUser;
  35
  36                 $this->mArticle =& $article;
  37                 $this->mTitle =& $article->mTitle;
  38                 $this->mNotificationTimestamp = NULL;
  39                 $this->mSkin = $wgUser->getSkin();
  40                 $this->preCacheMessages();
  41         }
  42
  43         /**
  44          * As we use the same small set of messages in various methods and that
  45          * they are called often, we call them once and save them in $this->message
  46          */
  47         function preCacheMessages() {
  48                 // Precache various messages
  49                 if( !isset( $this->message ) ) {
  50                         foreach( explode(' ', 'cur last rev-delundel' ) as $msg ) {
  51                                 $this->message[$msg] = wfMsgExt( $msg, array( 'escape') );
  52                         }
  53                 }
  54         }
  55
  56         /**
  57          * Print the history page for an article.
  58          *
  59          * @returns nothing
  60          */
  61         function history() {
  62                 global $wgOut, $wgRequest, $wgTitle;
  63
  64                 /*
  65                  * Allow client caching.
  66                  */
  67
  68                 if( $wgOut->checkLastModified( $this->mArticle->getTouched() ) )
  69                         /* Client cache fresh and headers sent, nothing more to do. */
  70                         return;
  71
  72                 wfProfileIn( __METHOD__ );
  73
  74                 /*
  75                  * Setup page variables.
  76                  */
  77                 $wgOut->setPageTitle( wfMsg( 'history-title', $this->mTitle->getPrefixedText() ) );
  78                 $wgOut->setPageTitleActionText( wfMsg( 'history_short' ) );
  79                 $wgOut->setArticleFlag( false );
  80                 $wgOut->setArticleRelated( true );
  81                 $wgOut->setRobotpolicy( 'noindex,nofollow' );
  82                 $wgOut->setSyndicated( true );
  83                 $wgOut->setFeedAppendQuery( 'action=history' );
  84                 $wgOut->addScriptFile( 'history.js' );
  85
  86                 $logPage = SpecialPage::getTitleFor( 'Log' );
  87                 $logLink = $this->mSkin->makeKnownLinkObj( $logPage, wfMsgHtml( 'viewpagelogs' ), 'page=' . $this->mTitle->getPrefixedUrl() );
  88                 $wgOut->setSubtitle( $logLink );
  89
  90                 $feedType = $wgRequest->getVal( 'feed' );
  91                 if( $feedType ) {
  92                         wfProfileOut( __METHOD__ );
  93                         return $this->feed( $feedType );
  94                 }
  95
  96                 /*
  97                  * Fail if article doesn't exist.
  98                  */
  99                 if( !$this->mTitle->exists() ) {
 100                         $wgOut->addWikiMsg( 'nohistory' );
 101                         wfProfileOut( __METHOD__ );
 102                         return;
 103                 }
 104
 105                 /*
 106                  * "go=first" means to jump to the last (earliest) history page.
 107                  * This is deprecated, it no longer appears in the user interface
 108                  */
 109                 if ( $wgRequest->getText("go") == 'first' ) {
 110                         $limit = $wgRequest->getInt( 'limit', 50 );
 111                         $wgOut->redirect( $wgTitle->getLocalURL( "action=history&limit={$limit}&dir=prev" ) );
 112                         return;
 113                 }
 114
 115                 wfRunHooks( 'PageHistoryBeforeList', array( &$this->mArticle ) );
 116
 117                 /**
 118                  * Do the list
 119                  */
 120                 $pager = new PageHistoryPager( $this );
 121                 $this->linesonpage = $pager->getNumRows();
 122                 $wgOut->addHTML(
 123                         $pager->getNavigationBar() .
 124                         $this->beginHistoryList() .
 125                         $pager->getBody() .
 126                         $this->endHistoryList() .
 127                         $pager->getNavigationBar()
 128                 );
 129                 wfProfileOut( __METHOD__ );
 130         }
 131
 132         /**
 133          * Creates begin of history list with a submit button
 134          *
 135          * @return string HTML output
 136          */
 137         function beginHistoryList() {
 138                 global $wgTitle;
 139                 $this->lastdate = '';
 140                 $s = wfMsgExt( 'histlegend', array( 'parse') );
 141                 $s .= '<form action="' . $wgTitle->escapeLocalURL( '-' ) . '" method="get">';
 142                 $prefixedkey = htmlspecialchars($wgTitle->getPrefixedDbKey());
 143
 144                 // The following line is SUPPOSED to have double-quotes around the
 145                 // $prefixedkey variable, because htmlspecialchars() doesn't escape
 146                 // single-quotes.
 147                 //
 148                 // On at least two occasions people have changed it to single-quotes,
 149                 // which creates invalid HTML and incorrect display of the resulting
 150                 // link.
 151                 //
 152                 // Please do not break this a third time. Thank you for your kind
 153                 // consideration and cooperation.
 154                 //
 155                 $s .= "<input type='hidden' name='title' value=\"{$prefixedkey}\" />\n";
 156
 157                 $s .= $this->submitButton();
 158                 $s .= '<ul id="pagehistory">' . "\n";
 159                 return $s;
 160         }
 161
 162         /**
 163          * Creates end of history list with a submit button
 164          *
 165          * @return string HTML output
 166          */
 167         function endHistoryList() {
 168                 $s = '</ul>';
 169                 $s .= $this->submitButton( array( 'id' => 'historysubmit' ) );
 170                 $s .= '</form>';
 171                 return $s;
 172         }
 173
 174         /**
 175          * Creates a submit button
 176          *
 177          * @param array $bits optional CSS ID
 178          * @return string HTML output for the submit button
 179          */
 180         function submitButton( $bits = array() ) {
 181                 # Disable submit button if history has 1 revision only
 182                 if ( $this->linesonpage > 1 ) {
 183                         return Xml::submitButton( wfMsg( 'compareselectedversions' ),
 184                                 $bits + array(
 185                                         'class'     => 'historysubmit',
 186                                         'accesskey' => wfMsg( 'accesskey-compareselectedversions' ),
 187                                         'title'     => wfMsg( 'tooltip-compareselectedversions' ),
 188                                         )
 189                                 );
 190                 } else {
 191                         return '';
 192                 }
 193         }
 194
 195         /**
 196          * Returns a row from the history printout.
 197          *
 198          * @todo document some more, and maybe clean up the code (some params redundant?)
 199          *
 200          * @param Row $row The database row corresponding to the previous line.
 201          * @param mixed $next The database row corresponding to the next line.
 202          * @param int $counter Apparently a counter of what row number we're at, counted from the top row = 1.
 203          * @param $notificationtimestamp
 204          * @param bool $latest Whether this row corresponds to the page's latest revision.
 205          * @param bool $firstInList Whether this row corresponds to the first displayed on this history page.
 206          * @return string HTML output for the row
 207          */
 208         function historyLine( $row, $next, $counter = '', $notificationtimestamp = false, $latest = false, $firstInList = false ) {
 209                 global $wgUser, $wgLang;
 210                 $rev = new Revision( $row );
 211                 $rev->setTitle( $this->mTitle );
 212
 213                 $s = '';
 214                 $curlink = $this->curLink( $rev, $latest );
 215                 $lastlink = $this->lastLink( $rev, $next, $counter );
 216                 $arbitrary = $this->diffButtons( $rev, $firstInList, $counter );
 217                 $link = $this->revLink( $rev );
 218
 219                 $s .= "($curlink) ($lastlink) $arbitrary";
 220
 221                 if( $wgUser->isAllowed( 'deleterevision' ) ) {
 222                         $revdel = SpecialPage::getTitleFor( 'Revisiondelete' );
 223                         if( $firstInList ) {
 224                         // We don't currently handle well changing the top revision's settings
 225                                 $del = $this->message['rev-delundel'];
 226                         } else if( !$rev->userCan( Revision::DELETED_RESTRICTED ) ) {
 227                         // If revision was hidden from sysops
 228                                 $del = $this->message['rev-delundel'];
 229                         } else {
 230                                 $del = $this->mSkin->makeKnownLinkObj( $revdel,
 231                                         $this->message['rev-delundel'],
 232                                         'target=' . urlencode( $this->mTitle->getPrefixedDbkey() ) .
 233                                         '&oldid=' . urlencode( $rev->getId() ) );
 234                                 // Bolden oversighted content
 235                                 if( $rev->isDeleted( Revision::DELETED_RESTRICTED ) )
 236                                         $del = "<strong>$del</strong>";
 237                         }
 238                         $s .= " <tt>(<small>$del</small>)</tt> ";
 239                 }
 240
 241                 $s .= " $link";
 242                 $s .= " <span class='history-user'>" . $this->mSkin->revUserTools( $rev, true ) . "</span>";
 243
 244                 if( $row->rev_minor_edit ) {
 245                         $s .= ' ' . Xml::element( 'span', array( 'class' => 'minor' ), wfMsg( 'minoreditletter') );
 246                 }
 247
 248                 if ( !is_null( $size = $rev->getSize() ) && $rev->userCan( Revision::DELETED_TEXT ) ) {
 249                         if ( $size == 0 )
 250                                 $stxt = wfMsgHtml( 'historyempty' );
 251                         else
 252                                 $stxt = wfMsgExt( 'historysize', array( 'parsemag' ), $wgLang->formatNum( $size ) );
 253                         $s .= " <span class=\"history-size\">$stxt</span>";
 254                 }
 255
 256                 $s .= $this->mSkin->revComment( $rev, false, true );
 257
 258                 if ($notificationtimestamp && ($row->rev_timestamp >= $notificationtimestamp)) {
 259                         $s .= ' <span class="updatedmarker">' .  wfMsgHtml( 'updatedmarker' ) . '</span>';
 260                 }
 261                 #add blurb about text having been deleted
 262                 if( $rev->isDeleted( Revision::DELETED_TEXT ) ) {
 263                         $s .= ' <tt>' . wfMsgHtml( 'deletedrev' ) . '</tt>';
 264                 }
 265
 266                 $tools = array();
 267
 268                 if ( !is_null( $next ) && is_object( $next ) ) {
 269                         if( !$this->mTitle->getUserPermissionsErrors( 'rollback', $wgUser )
 270                         && !$this->mTitle->getUserPermissionsErrors( 'edit', $wgUser )
 271                         && $latest ) {
 272                                 $tools[] = '<span class="mw-rollback-link">'
 273                                         . $this->mSkin->buildRollbackLink( $rev )
 274                                         . '</span>';
 275                         }
 276
 277                         if( $this->mTitle->quickUserCan( 'edit' ) &&
 278                                 !$rev->isDeleted( Revision::DELETED_TEXT ) &&
 279                                 !$next->rev_deleted & Revision::DELETED_TEXT ) {
 280                                 $undolink = $this->mSkin->makeKnownLinkObj(
 281                                         $this->mTitle,
 282                                         wfMsgHtml( 'editundo' ),
 283                                         'action=edit&undoafter=' . $next->rev_id . '&undo=' . $rev->getId()
 284                                 );
 285                                 $tools[] = "<span class=\"mw-history-undo\">{$undolink}</span>";
 286                         }
 287                 }
 288
 289                 if( $tools ) {
 290                         $s .= ' (' . implode( ' | ', $tools ) . ')';
 291                 }
 292
 293                 wfRunHooks( 'PageHistoryLineEnding', array( &$row , &$s ) );
 294
 295                 return "<li>$s</li>\n";
 296         }
 297
 298         /**
 299         * Create a link to view this revision of the page
 300         * @param Revision $rev
 301         * @returns string
 302         */
 303         function revLink( $rev ) {
 304                 global $wgLang;
 305                 $date = $wgLang->timeanddate( wfTimestamp(TS_MW, $rev->getTimestamp()), true );
 306                 if( $rev->userCan( Revision::DELETED_TEXT ) ) {
 307                         $link = $this->mSkin->makeKnownLinkObj(
 308                                 $this->mTitle, $date, "oldid=" . $rev->getId() );
 309                 } else {
 310                         $link = $date;
 311                 }
 312                 if( $rev->isDeleted( Revision::DELETED_TEXT ) ) {
 313                         return '<span class="history-deleted">' . $link . '</span>';
 314                 }
 315                 return $link;
 316         }
 317
 318         /**
 319         * Create a diff-to-current link for this revision for this page
 320         * @param Revision $rev
 321         * @param Bool $latest, this is the latest revision of the page?
 322         * @returns string
 323         */
 324         function curLink( $rev, $latest ) {
 325                 $cur = $this->message['cur'];
 326                 if( $latest || !$rev->userCan( Revision::DELETED_TEXT ) ) {
 327                         return $cur;
 328                 } else {
 329                         return $this->mSkin->makeKnownLinkObj(
 330                                 $this->mTitle, $cur,
 331                                 'diff=' . $this->getLatestID() .
 332                                 "&oldid=" . $rev->getId() );
 333                 }
 334         }
 335
 336         /**
 337         * Create a diff-to-previous link for this revision for this page.
 338         * @param Revision $prevRev, the previous revision
 339         * @param mixed $next, the newer revision
 340         * @param int $counter, what row on the history list this is
 341         * @returns string
 342         */
 343         function lastLink( $prevRev, $next, $counter ) {
 344                 $last = $this->message['last'];
 345                 # $next may either be a Row, null, or "unkown"
 346                 $nextRev = is_object($next) ? new Revision( $next ) : $next;
 347                 if( is_null($next) ) {
 348                         # Probably no next row
 349                         return $last;
 350                 } elseif( $next === 'unknown' ) {
 351                         # Next row probably exists but is unknown, use an oldid=prev link
 352                         return $this->mSkin->makeKnownLinkObj(
 353                                 $this->mTitle,
 354                                 $last,
 355                                 "diff=" . $prevRev->getId() . "&oldid=prev" );
 356                 } elseif( !$prevRev->userCan(Revision::DELETED_TEXT) || !$nextRev->userCan(Revision::DELETED_TEXT) ) {
 357                         return $last;
 358                 } else {
 359                         return $this->mSkin->makeKnownLinkObj(
 360                                 $this->mTitle,
 361                                 $last,
 362                                 "diff=" . $prevRev->getId() . "&oldid={$next->rev_id}"
 363                                 /*,
 364                                 '',
 365                                 '',
 366                                 "tabindex={$counter}"*/ );
 367                 }
 368         }
 369
 370         /**
 371          * Create radio buttons for page history
 372          *
 373          * @param object $rev Revision
 374          * @param bool $firstInList Is this version the first one?
 375          * @param int $counter A counter of what row number we're at, counted from the top row = 1.
 376          * @return string HTML output for the radio buttons
 377          */
 378         function diffButtons( $rev, $firstInList, $counter ) {
 379                 if( $this->linesonpage > 1) {
 380                         $radio = array(
 381                                 'type'  => 'radio',
 382                                 'value' => $rev->getId(),
 383                         );
 384
 385                         if( !$rev->userCan( Revision::DELETED_TEXT ) ) {
 386                                 $radio['disabled'] = 'disabled';
 387                         }
 388
 389                         /** @todo: move title texts to javascript */
 390                         if ( $firstInList ) {
 391                                 $first = Xml::element( 'input', array_merge(
 392                                         $radio,
 393                                         array(
 394                                                 'style' => 'visibility:hidden',
 395                                                 'name'  => 'oldid' ) ) );
 396                                 $checkmark = array( 'checked' => 'checked' );
 397                         } else {
 398                                 if( $counter == 2 ) {
 399                                         $checkmark = array( 'checked' => 'checked' );
 400                                 } else {
 401                                         $checkmark = array();
 402                                 }
 403                                 $first = Xml::element( 'input', array_merge(
 404                                         $radio,
 405                                         $checkmark,
 406                                         array( 'name'  => 'oldid' ) ) );
 407                                 $checkmark = array();
 408                         }
 409                         $second = Xml::element( 'input', array_merge(
 410                                 $radio,
 411                                 $checkmark,
 412                                 array( 'name'  => 'diff' ) ) );
 413                         return $first . $second;
 414                 } else {
 415                         return '';
 416                 }
 417         }
 418
 419         /** @todo document */
 420         function getLatestId() {
 421                 if( is_null( $this->mLatestId ) ) {
 422                         $id = $this->mTitle->getArticleID();
 423                         $db = wfGetDB( DB_SLAVE );
 424                         $this->mLatestId = $db->selectField( 'page',
 425                                 "page_latest",
 426                                 array( 'page_id' => $id ),
 427                                 __METHOD__ );
 428                 }
 429                 return $this->mLatestId;
 430         }
 431
 432         /**
 433          * Fetch an array of revisions, specified by a given limit, offset and
 434          * direction. This is now only used by the feeds. It was previously
 435          * used by the main UI but that's now handled by the pager.
 436          */
 437         function fetchRevisions($limit, $offset, $direction) {
 438                 $dbr = wfGetDB( DB_SLAVE );
 439
 440                 if ($direction == PageHistory::DIR_PREV)
 441                         list($dirs, $oper) = array("ASC", ">=");
 442                 else /* $direction == PageHistory::DIR_NEXT */
 443                         list($dirs, $oper) = array("DESC", "<=");
 444
 445                 if ($offset)
 446                         $offsets = array("rev_timestamp $oper '$offset'");
 447                 else
 448                         $offsets = array();
 449
 450                 $page_id = $this->mTitle->getArticleID();
 451
 452                 $res = $dbr->select(
 453                         'revision',
 454                         Revision::selectFields(),
 455                         array_merge(array("rev_page=$page_id"), $offsets),
 456                         __METHOD__,
 457                         array('ORDER BY' => "rev_timestamp $dirs",
 458                                 'USE INDEX' => 'page_timestamp', 'LIMIT' => $limit)
 459                         );
 460
 461                 $result = array();
 462                 while (($obj = $dbr->fetchObject($res)) != NULL)
 463                         $result[] = $obj;
 464
 465                 return $result;
 466         }
 467
 468         /** @todo document */
 469         function getNotificationTimestamp() {
 470                 global $wgUser, $wgShowUpdatedMarker;
 471
 472                 if ($this->mNotificationTimestamp !== NULL)
 473                         return $this->mNotificationTimestamp;
 474
 475                 if ($wgUser->isAnon() || !$wgShowUpdatedMarker)
 476                         return $this->mNotificationTimestamp = false;
 477
 478                 $dbr = wfGetDB(DB_SLAVE);
 479
 480                 $this->mNotificationTimestamp = $dbr->selectField(
 481                         'watchlist',
 482                         'wl_notificationtimestamp',
 483                         array(  'wl_namespace' => $this->mTitle->getNamespace(),
 484                                 'wl_title' => $this->mTitle->getDBkey(),
 485                                 'wl_user' => $wgUser->getID()
 486                         ),
 487                         __METHOD__ );
 488
 489                 // Don't use the special value reserved for telling whether the field is filled
 490                 if ( is_null( $this->mNotificationTimestamp ) ) {
 491                         $this->mNotificationTimestamp = false;
 492                 }
 493
 494                 return $this->mNotificationTimestamp;
 495         }
 496
 497         /**
 498          * Output a subscription feed listing recent edits to this page.
 499          * @param string $type
 500          */
 501         function feed( $type ) {
 502                 require_once 'SpecialRecentchanges.php';
 503
 504                 global $wgFeed, $wgFeedClasses;
 505
 506                 if ( !$wgFeed ) {
 507                         global $wgOut;
 508                         $wgOut->addWikiMsg( 'feed-unavailable' );
 509                         return;
 510                 }
 511
 512                 if( !isset( $wgFeedClasses[$type] ) ) {
 513                         global $wgOut;
 514                         $wgOut->addWikiMsg( 'feed-invalid' );
 515                         return;
 516                 }
 517
 518                 $feed = new $wgFeedClasses[$type](
 519                         $this->mTitle->getPrefixedText() . ' - ' .
 520                                 wfMsgForContent( 'history-feed-title' ),
 521                         wfMsgForContent( 'history-feed-description' ),
 522                         $this->mTitle->getFullUrl( 'action=history' ) );
 523
 524                 $items = $this->fetchRevisions(10, 0, PageHistory::DIR_NEXT);
 525                 $feed->outHeader();
 526                 if( $items ) {
 527                         foreach( $items as $row ) {
 528                                 $feed->outItem( $this->feedItem( $row ) );
 529                         }
 530                 } else {
 531                         $feed->outItem( $this->feedEmpty() );
 532                 }
 533                 $feed->outFooter();
 534         }
 535
 536         function feedEmpty() {
 537                 global $wgOut;
 538                 return new FeedItem(
 539                         wfMsgForContent( 'nohistory' ),
 540                         $wgOut->parse( wfMsgForContent( 'history-feed-empty' ) ),
 541                         $this->mTitle->getFullUrl(),
 542                         wfTimestamp( TS_MW ),
 543                         '',
 544                         $this->mTitle->getTalkPage()->getFullUrl() );
 545         }
 546
 547         /**
 548          * Generate a FeedItem object from a given revision table row
 549          * Borrows Recent Changes' feed generation functions for formatting;
 550          * includes a diff to the previous revision (if any).
 551          *
 552          * @param $row
 553          * @return FeedItem
 554          */
 555         function feedItem( $row ) {
 556                 $rev = new Revision( $row );
 557                 $rev->setTitle( $this->mTitle );
 558                 $text = rcFormatDiffRow( $this->mTitle,
 559                         $this->mTitle->getPreviousRevisionID( $rev->getId() ),
 560                         $rev->getId(),
 561                         $rev->getTimestamp(),
 562                         $rev->getComment() );
 563
 564                 if( $rev->getComment() == '' ) {
 565                         global $wgContLang;
 566                         $title = wfMsgForContent( 'history-feed-item-nocomment',
 567                                 $rev->getUserText(),
 568                                 $wgContLang->timeanddate( $rev->getTimestamp() ) );
 569                 } else {
 570                         $title = $rev->getUserText() . ": " . $this->stripComment( $rev->getComment() );
 571                 }
 572
 573                 return new FeedItem(
 574                         $title,
 575                         $text,
 576                         $this->mTitle->getFullUrl( 'diff=' . $rev->getId() . '&oldid=prev' ),
 577                         $rev->getTimestamp(),
 578                         $rev->getUserText(),
 579                         $this->mTitle->getTalkPage()->getFullUrl() );
 580         }
 581
 582         /**
 583          * Quickie hack... strip out wikilinks to more legible form from the comment.
 584          */
 585         function stripComment( $text ) {
 586                 return preg_replace( '/\[\[([^]]*\|)?([^]]+)\]\]/', '\2', $text );
 587         }
 588 }
 589
 590
 591 /**
 592  * @addtogroup Pager
 593  */
 594 class PageHistoryPager extends ReverseChronologicalPager {
 595         public $mLastRow = false, $mPageHistory;
 596
 597         function __construct( $pageHistory ) {
 598                 parent::__construct();
 599                 $this->mPageHistory = $pageHistory;
 600         }
 601
 602         function getQueryInfo() {
 603                 return array(
 604                         'tables' => 'revision',
 605                         'fields' => Revision::selectFields(),
 606                         'conds' => array('rev_page' => $this->mPageHistory->mTitle->getArticleID() ),
 607                         'options' => array( 'USE INDEX' => 'page_timestamp' )
 608                 );
 609         }
 610
 611         function getIndexField() {
 612                 return 'rev_timestamp';
 613         }
 614
 615         function formatRow( $row ) {
 616                 if ( $this->mLastRow ) {
 617                         $latest = $this->mCounter == 1 && $this->mIsFirst;
 618                         $firstInList = $this->mCounter == 1;
 619                         $s = $this->mPageHistory->historyLine( $this->mLastRow, $row, $this->mCounter++,
 620                                 $this->mPageHistory->getNotificationTimestamp(), $latest, $firstInList );
 621                 } else {
 622                         $s = '';
 623                 }
 624                 $this->mLastRow = $row;
 625                 return $s;
 626         }
 627
 628         function getStartBody() {
 629                 $this->mLastRow = false;
 630                 $this->mCounter = 1;
 631                 return '';
 632         }
 633
 634         function getEndBody() {
 635                 if ( $this->mLastRow ) {
 636                         $latest = $this->mCounter == 1 && $this->mIsFirst;
 637                         $firstInList = $this->mCounter == 1;
 638                         if ( $this->mIsBackwards ) {
 639                                 # Next row is unknown, but for UI reasons, probably exists if an offset has been specified
 640                                 if ( $this->mOffset == '' ) {
 641                                         $next = null;
 642                                 } else {
 643                                         $next = 'unknown';
 644                                 }
 645                         } else {
 646                                 # The next row is the past-the-end row
 647                                 $next = $this->mPastTheEndRow;
 648                         }
 649                         $s = $this->mPageHistory->historyLine( $this->mLastRow, $next, $this->mCounter++,
 650                                 $this->mPageHistory->getNotificationTimestamp(), $latest, $firstInList );
 651                 } else {
 652                         $s = '';
 653                 }
 654                 return $s;
 655         }
 656 }