includes/PageHistory.php

   1 <?php
   2 /**
   3  * Page history
   4  *
   5  * Split off from Article.php and Skin.php, 2003-12-22
   6  * @file
   7  */
   8
   9 /**
  10  * This class handles printing the history page for an article.  In order to
  11  * be efficient, it uses timestamps rather than offsets for paging, to avoid
  12  * costly LIMIT,offset queries.
  13  *
  14  * Construct it by passing in an Article, and call $h->history() to print the
  15  * history.
  16  *
  17  */
  18 class PageHistory {
  19         const DIR_PREV = 0;
  20         const DIR_NEXT = 1;
  21
  22         var $mArticle, $mTitle, $mSkin;
  23         var $lastdate;
  24         var $linesonpage;
  25         var $mNotificationTimestamp;
  26         var $mLatestId = null;
  27
  28         /**
  29          * Construct a new PageHistory.
  30          *
  31          * @param Article $article
  32          * @returns nothing
  33          */
  34         function __construct($article) {
  35                 global $wgUser;
  36
  37                 $this->mArticle =& $article;
  38                 $this->mTitle =& $article->mTitle;
  39                 $this->mNotificationTimestamp = NULL;
  40                 $this->mSkin = $wgUser->getSkin();
  41                 $this->preCacheMessages();
  42         }
  43
  44         function getArticle() {
  45                 return $this->mArticle;
  46         }
  47
  48         function getTitle() {
  49                 return $this->mTitle;
  50         }
  51
  52         /**
  53          * As we use the same small set of messages in various methods and that
  54          * they are called often, we call them once and save them in $this->message
  55          */
  56         function preCacheMessages() {
  57                 // Precache various messages
  58                 if( !isset( $this->message ) ) {
  59                         foreach( explode(' ', 'cur last rev-delundel' ) as $msg ) {
  60                                 $this->message[$msg] = wfMsgExt( $msg, array( 'escape') );
  61                         }
  62                 }
  63         }
  64
  65         /**
  66          * Print the history page for an article.
  67          *
  68          * @returns nothing
  69          */
  70         function history() {
  71                 global $wgOut, $wgRequest, $wgTitle;
  72
  73                 /*
  74                  * Allow client caching.
  75                  */
  76
  77                 if( $wgOut->checkLastModified( $this->mArticle->getTouched() ) )
  78                         /* Client cache fresh and headers sent, nothing more to do. */
  79                         return;
  80
  81                 wfProfileIn( __METHOD__ );
  82
  83                 /*
  84                  * Setup page variables.
  85                  */
  86                 $wgOut->setPageTitle( wfMsg( 'history-title', $this->mTitle->getPrefixedText() ) );
  87                 $wgOut->setPageTitleActionText( wfMsg( 'history_short' ) );
  88                 $wgOut->setArticleFlag( false );
  89                 $wgOut->setArticleRelated( true );
  90                 $wgOut->setRobotpolicy( 'noindex,nofollow' );
  91                 $wgOut->setSyndicated( true );
  92                 $wgOut->setFeedAppendQuery( 'action=history' );
  93                 $wgOut->addScriptFile( 'history.js' );
  94
  95                 $logPage = SpecialPage::getTitleFor( 'Log' );
  96                 $logLink = $this->mSkin->makeKnownLinkObj( $logPage, wfMsgHtml( 'viewpagelogs' ), 'page=' . $this->mTitle->getPrefixedUrl() );
  97                 $wgOut->setSubtitle( $logLink );
  98
  99                 $feedType = $wgRequest->getVal( 'feed' );
 100                 if( $feedType ) {
 101                         wfProfileOut( __METHOD__ );
 102                         return $this->feed( $feedType );
 103                 }
 104
 105                 /*
 106                  * Fail if article doesn't exist.
 107                  */
 108                 if( !$this->mTitle->exists() ) {
 109                         $wgOut->addWikiMsg( 'nohistory' );
 110                         wfProfileOut( __METHOD__ );
 111                         return;
 112                 }
 113
 114                 /*
 115                  * "go=first" means to jump to the last (earliest) history page.
 116                  * This is deprecated, it no longer appears in the user interface
 117                  */
 118                 if ( $wgRequest->getText("go") == 'first' ) {
 119                         $limit = $wgRequest->getInt( 'limit', 50 );
 120                         global $wgFeedLimit;
 121                         if( $limit > $wgFeedLimit ) {
 122                                 $limit = $wgFeedLimit;
 123                         }
 124                         $wgOut->redirect( $wgTitle->getLocalURL( "action=history&limit={$limit}&dir=prev" ) );
 125                         return;
 126                 }
 127
 128                 wfRunHooks( 'PageHistoryBeforeList', array( &$this->mArticle ) );
 129
 130                 /**
 131                  * Do the list
 132                  */
 133                 $pager = new PageHistoryPager( $this );
 134                 $this->linesonpage = $pager->getNumRows();
 135                 $wgOut->addHTML(
 136                         $pager->getNavigationBar() .
 137                         $this->beginHistoryList() .
 138                         $pager->getBody() .
 139                         $this->endHistoryList() .
 140                         $pager->getNavigationBar()
 141                 );
 142                 wfProfileOut( __METHOD__ );
 143         }
 144
 145         /**
 146          * Creates begin of history list with a submit button
 147          *
 148          * @return string HTML output
 149          */
 150         function beginHistoryList() {
 151                 global $wgTitle, $wgScript;
 152                 $this->lastdate = '';
 153                 $s = wfMsgExt( 'histlegend', array( 'parse') );
 154                 $s .= Xml::openElement( 'form', array( 'action' => $wgScript ) );
 155                 $s .= Xml::hidden( 'title', $wgTitle->getPrefixedDbKey() );
 156                 $s .= $this->submitButton();
 157                 $s .= '<ul id="pagehistory">' . "\n";
 158                 return $s;
 159         }
 160
 161         /**
 162          * Creates end of history list with a submit button
 163          *
 164          * @return string HTML output
 165          */
 166         function endHistoryList() {
 167                 $s = '</ul>';
 168                 $s .= $this->submitButton( array( 'id' => 'historysubmit' ) );
 169                 $s .= '</form>';
 170                 return $s;
 171         }
 172
 173         /**
 174          * Creates a submit button
 175          *
 176          * @param array $bits optional CSS ID
 177          * @return string HTML output for the submit button
 178          */
 179         function submitButton( $bits = array() ) {
 180                 # Disable submit button if history has 1 revision only
 181                 if ( $this->linesonpage > 1 ) {
 182                         return Xml::submitButton( wfMsg( 'compareselectedversions' ),
 183                                 $bits + array(
 184                                         'class'     => 'historysubmit',
 185                                         'accesskey' => wfMsg( 'accesskey-compareselectedversions' ),
 186                                         'title'     => wfMsg( 'tooltip-compareselectedversions' ),
 187                                         )
 188                                 );
 189                 } else {
 190                         return '';
 191                 }
 192         }
 193
 194         /**
 195          * Returns a row from the history printout.
 196          *
 197          * @todo document some more, and maybe clean up the code (some params redundant?)
 198          *
 199          * @param Row $row The database row corresponding to the previous line.
 200          * @param mixed $next The database row corresponding to the next line.
 201          * @param int $counter Apparently a counter of what row number we're at, counted from the top row = 1.
 202          * @param $notificationtimestamp
 203          * @param bool $latest Whether this row corresponds to the page's latest revision.
 204          * @param bool $firstInList Whether this row corresponds to the first displayed on this history page.
 205          * @return string HTML output for the row
 206          */
 207         function historyLine( $row, $next, $counter = '', $notificationtimestamp = false, $latest = false, $firstInList = false ) {
 208                 global $wgUser, $wgLang;
 209                 $rev = new Revision( $row );
 210                 $rev->setTitle( $this->mTitle );
 211
 212                 $s = '';
 213                 $curlink = $this->curLink( $rev, $latest );
 214                 $lastlink = $this->lastLink( $rev, $next, $counter );
 215                 $arbitrary = $this->diffButtons( $rev, $firstInList, $counter );
 216                 $link = $this->revLink( $rev );
 217
 218                 $s .= "($curlink) ($lastlink) $arbitrary";
 219
 220                 if( $wgUser->isAllowed( 'deleterevision' ) ) {
 221                         $revdel = SpecialPage::getTitleFor( 'Revisiondelete' );
 222                         if( $firstInList ) {
 223                         // We don't currently handle well changing the top revision's settings
 224                                 $del = $this->message['rev-delundel'];
 225                         } else if( !$rev->userCan( Revision::DELETED_RESTRICTED ) ) {
 226                         // If revision was hidden from sysops
 227                                 $del = $this->message['rev-delundel'];
 228                         } else {
 229                                 $del = $this->mSkin->makeKnownLinkObj( $revdel,
 230                                         $this->message['rev-delundel'],
 231                                         'target=' . urlencode( $this->mTitle->getPrefixedDbkey() ) .
 232                                         '&oldid=' . urlencode( $rev->getId() ) );
 233                                 // Bolden oversighted content
 234                                 if( $rev->isDeleted( Revision::DELETED_RESTRICTED ) )
 235                                         $del = "<strong>$del</strong>";
 236                         }
 237                         $s .= " <tt>(<small>$del</small>)</tt> ";
 238                 }
 239
 240                 $s .= " $link";
 241                 $s .= " <span class='history-user'>" . $this->mSkin->revUserTools( $rev, true ) . "</span>";
 242
 243                 if( $row->rev_minor_edit ) {
 244                         $s .= ' ' . Xml::element( 'span', array( 'class' => 'minor' ), wfMsg( 'minoreditletter') );
 245                 }
 246
 247                 if ( !is_null( $size = $rev->getSize() ) && $rev->userCan( Revision::DELETED_TEXT ) ) {
 248                         if ( $size == 0 )
 249                                 $stxt = wfMsgHtml( 'historyempty' );
 250                         else
 251                                 $stxt = wfMsgExt( 'historysize', array( 'parsemag' ), $wgLang->formatNum( $size ) );
 252                         $s .= " <span class=\"history-size\">$stxt</span>";
 253                 }
 254
 255                 $s .= $this->mSkin->revComment( $rev, false, true );
 256
 257                 if ($notificationtimestamp && ($row->rev_timestamp >= $notificationtimestamp)) {
 258                         $s .= ' <span class="updatedmarker">' .  wfMsgHtml( 'updatedmarker' ) . '</span>';
 259                 }
 260                 #add blurb about text having been deleted
 261                 if( $rev->isDeleted( Revision::DELETED_TEXT ) ) {
 262                         $s .= ' <tt>' . wfMsgHtml( 'deletedrev' ) . '</tt>';
 263                 }
 264
 265                 $tools = array();
 266
 267                 if ( !is_null( $next ) && is_object( $next ) ) {
 268                         if( !$this->mTitle->getUserPermissionsErrors( 'rollback', $wgUser )
 269                         && !$this->mTitle->getUserPermissionsErrors( 'edit', $wgUser )
 270                         && $latest ) {
 271                                 $tools[] = '<span class="mw-rollback-link">'
 272                                         . $this->mSkin->buildRollbackLink( $rev )
 273                                         . '</span>';
 274                         }
 275
 276                         if( $this->mTitle->quickUserCan( 'edit' ) &&
 277                                 !$rev->isDeleted( Revision::DELETED_TEXT ) &&
 278                                 !$next->rev_deleted & Revision::DELETED_TEXT ) {
 279                                 $undolink = $this->mSkin->makeKnownLinkObj(
 280                                         $this->mTitle,
 281                                         wfMsgHtml( 'editundo' ),
 282                                         'action=edit&undoafter=' . $next->rev_id . '&undo=' . $rev->getId()
 283                                 );
 284                                 $tools[] = "<span class=\"mw-history-undo\">{$undolink}</span>";
 285                         }
 286                 }
 287
 288                 if( $tools ) {
 289                         $s .= ' (' . implode( ' | ', $tools ) . ')';
 290                 }
 291
 292                 wfRunHooks( 'PageHistoryLineEnding', array( $this, &$row , &$s ) );
 293
 294                 return "<li>$s</li>\n";
 295         }
 296
 297         /**
 298         * Create a link to view this revision of the page
 299         * @param Revision $rev
 300         * @returns string
 301         */
 302         function revLink( $rev ) {
 303                 global $wgLang;
 304                 $date = $wgLang->timeanddate( wfTimestamp(TS_MW, $rev->getTimestamp()), true );
 305                 if( $rev->userCan( Revision::DELETED_TEXT ) ) {
 306                         $link = $this->mSkin->makeKnownLinkObj(
 307                                 $this->mTitle, $date, "oldid=" . $rev->getId() );
 308                 } else {
 309                         $link = $date;
 310                 }
 311                 if( $rev->isDeleted( Revision::DELETED_TEXT ) ) {
 312                         return '<span class="history-deleted">' . $link . '</span>';
 313                 }
 314                 return $link;
 315         }
 316
 317         /**
 318         * Create a diff-to-current link for this revision for this page
 319         * @param Revision $rev
 320         * @param Bool $latest, this is the latest revision of the page?
 321         * @returns string
 322         */
 323         function curLink( $rev, $latest ) {
 324                 $cur = $this->message['cur'];
 325                 if( $latest || !$rev->userCan( Revision::DELETED_TEXT ) ) {
 326                         return $cur;
 327                 } else {
 328                         return $this->mSkin->makeKnownLinkObj(
 329                                 $this->mTitle, $cur,
 330                                 'diff=' . $this->getLatestID() .
 331                                 "&oldid=" . $rev->getId() );
 332                 }
 333         }
 334
 335         /**
 336         * Create a diff-to-previous link for this revision for this page.
 337         * @param Revision $prevRev, the previous revision
 338         * @param mixed $next, the newer revision
 339         * @param int $counter, what row on the history list this is
 340         * @returns string
 341         */
 342         function lastLink( $prevRev, $next, $counter ) {
 343                 $last = $this->message['last'];
 344                 # $next may either be a Row, null, or "unkown"
 345                 $nextRev = is_object($next) ? new Revision( $next ) : $next;
 346                 if( is_null($next) ) {
 347                         # Probably no next row
 348                         return $last;
 349                 } elseif( $next === 'unknown' ) {
 350                         # Next row probably exists but is unknown, use an oldid=prev link
 351                         return $this->mSkin->makeKnownLinkObj(
 352                                 $this->mTitle,
 353                                 $last,
 354                                 "diff=" . $prevRev->getId() . "&oldid=prev" );
 355                 } elseif( !$prevRev->userCan(Revision::DELETED_TEXT) || !$nextRev->userCan(Revision::DELETED_TEXT) ) {
 356                         return $last;
 357                 } else {
 358                         return $this->mSkin->makeKnownLinkObj(
 359                                 $this->mTitle,
 360                                 $last,
 361                                 "diff=" . $prevRev->getId() . "&oldid={$next->rev_id}"
 362                                 /*,
 363                                 '',
 364                                 '',
 365                                 "tabindex={$counter}"*/ );
 366                 }
 367         }
 368
 369         /**
 370          * Create radio buttons for page history
 371          *
 372          * @param object $rev Revision
 373          * @param bool $firstInList Is this version the first one?
 374          * @param int $counter A counter of what row number we're at, counted from the top row = 1.
 375          * @return string HTML output for the radio buttons
 376          */
 377         function diffButtons( $rev, $firstInList, $counter ) {
 378                 if( $this->linesonpage > 1) {
 379                         $radio = array(
 380                                 'type'  => 'radio',
 381                                 'value' => $rev->getId(),
 382                         );
 383
 384                         if( !$rev->userCan( Revision::DELETED_TEXT ) ) {
 385                                 $radio['disabled'] = 'disabled';
 386                         }
 387
 388                         /** @todo: move title texts to javascript */
 389                         if ( $firstInList ) {
 390                                 $first = Xml::element( 'input', array_merge(
 391                                         $radio,
 392                                         array(
 393                                                 'style' => 'visibility:hidden',
 394                                                 'name'  => 'oldid' ) ) );
 395                                 $checkmark = array( 'checked' => 'checked' );
 396                         } else {
 397                                 if( $counter == 2 ) {
 398                                         $checkmark = array( 'checked' => 'checked' );
 399                                 } else {
 400                                         $checkmark = array();
 401                                 }
 402                                 $first = Xml::element( 'input', array_merge(
 403                                         $radio,
 404                                         $checkmark,
 405                                         array( 'name'  => 'oldid' ) ) );
 406                                 $checkmark = array();
 407                         }
 408                         $second = Xml::element( 'input', array_merge(
 409                                 $radio,
 410                                 $checkmark,
 411                                 array( 'name'  => 'diff' ) ) );
 412                         return $first . $second;
 413                 } else {
 414                         return '';
 415                 }
 416         }
 417
 418         /** @todo document */
 419         function getLatestId() {
 420                 if( is_null( $this->mLatestId ) ) {
 421                         $id = $this->mTitle->getArticleID();
 422                         $db = wfGetDB( DB_SLAVE );
 423                         $this->mLatestId = $db->selectField( 'page',
 424                                 "page_latest",
 425                                 array( 'page_id' => $id ),
 426                                 __METHOD__ );
 427                 }
 428                 return $this->mLatestId;
 429         }
 430
 431         /**
 432          * Fetch an array of revisions, specified by a given limit, offset and
 433          * direction. This is now only used by the feeds. It was previously
 434          * used by the main UI but that's now handled by the pager.
 435          */
 436         function fetchRevisions($limit, $offset, $direction) {
 437                 $dbr = wfGetDB( DB_SLAVE );
 438
 439                 if ($direction == PageHistory::DIR_PREV)
 440                         list($dirs, $oper) = array("ASC", ">=");
 441                 else /* $direction == PageHistory::DIR_NEXT */
 442                         list($dirs, $oper) = array("DESC", "<=");
 443
 444                 if ($offset)
 445                         $offsets = array("rev_timestamp $oper '$offset'");
 446                 else
 447                         $offsets = array();
 448
 449                 $page_id = $this->mTitle->getArticleID();
 450
 451                 $res = $dbr->select(
 452                         'revision',
 453                         Revision::selectFields(),
 454                         array_merge(array("rev_page=$page_id"), $offsets),
 455                         __METHOD__,
 456                         array('ORDER BY' => "rev_timestamp $dirs",
 457                                 'USE INDEX' => 'page_timestamp', 'LIMIT' => $limit)
 458                         );
 459
 460                 $result = array();
 461                 while (($obj = $dbr->fetchObject($res)) != NULL)
 462                         $result[] = $obj;
 463
 464                 return $result;
 465         }
 466
 467         /** @todo document */
 468         function getNotificationTimestamp() {
 469                 global $wgUser, $wgShowUpdatedMarker;
 470
 471                 if ($this->mNotificationTimestamp !== NULL)
 472                         return $this->mNotificationTimestamp;
 473
 474                 if ($wgUser->isAnon() || !$wgShowUpdatedMarker)
 475                         return $this->mNotificationTimestamp = false;
 476
 477                 $dbr = wfGetDB(DB_SLAVE);
 478
 479                 $this->mNotificationTimestamp = $dbr->selectField(
 480                         'watchlist',
 481                         'wl_notificationtimestamp',
 482                         array(  'wl_namespace' => $this->mTitle->getNamespace(),
 483                                 'wl_title' => $this->mTitle->getDBkey(),
 484                                 'wl_user' => $wgUser->getId()
 485                         ),
 486                         __METHOD__ );
 487
 488                 // Don't use the special value reserved for telling whether the field is filled
 489                 if ( is_null( $this->mNotificationTimestamp ) ) {
 490                         $this->mNotificationTimestamp = false;
 491                 }
 492
 493                 return $this->mNotificationTimestamp;
 494         }
 495
 496         /**
 497          * Output a subscription feed listing recent edits to this page.
 498          * @param string $type
 499          */
 500         function feed( $type ) {
 501                 global $IP;
 502                 require_once "$IP/includes/specials/Recentchanges.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  * @ingroup 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                 $queryInfo = array(
 604                         'tables' => array('revision'),
 605                         'fields' => Revision::selectFields(),
 606                         'conds' => array('rev_page' => $this->mPageHistory->mTitle->getArticleID() ),
 607                         'options' => array( 'USE INDEX' => array('revision','page_timestamp') )
 608                 );
 609                 wfRunHooks( 'PageHistoryPager::getQueryInfo', array( &$this, &$queryInfo ) );
 610                 return $queryInfo;
 611         }
 612
 613         function getIndexField() {
 614                 return 'rev_timestamp';
 615         }
 616
 617         function formatRow( $row ) {
 618                 if ( $this->mLastRow ) {
 619                         $latest = $this->mCounter == 1 && $this->mIsFirst;
 620                         $firstInList = $this->mCounter == 1;
 621                         $s = $this->mPageHistory->historyLine( $this->mLastRow, $row, $this->mCounter++,
 622                                 $this->mPageHistory->getNotificationTimestamp(), $latest, $firstInList );
 623                 } else {
 624                         $s = '';
 625                 }
 626                 $this->mLastRow = $row;
 627                 return $s;
 628         }
 629
 630         function getStartBody() {
 631                 $this->mLastRow = false;
 632                 $this->mCounter = 1;
 633                 return '';
 634         }
 635
 636         function getEndBody() {
 637                 if ( $this->mLastRow ) {
 638                         $latest = $this->mCounter == 1 && $this->mIsFirst;
 639                         $firstInList = $this->mCounter == 1;
 640                         if ( $this->mIsBackwards ) {
 641                                 # Next row is unknown, but for UI reasons, probably exists if an offset has been specified
 642                                 if ( $this->mOffset == '' ) {
 643                                         $next = null;
 644                                 } else {
 645                                         $next = 'unknown';
 646                                 }
 647                         } else {
 648                                 # The next row is the past-the-end row
 649                                 $next = $this->mPastTheEndRow;
 650                         }
 651                         $s = $this->mPageHistory->historyLine( $this->mLastRow, $next, $this->mCounter++,
 652                                 $this->mPageHistory->getNotificationTimestamp(), $latest, $firstInList );
 653                 } else {
 654                         $s = '';
 655                 }
 656                 return $s;
 657         }
 658 }