includes/HistoryPage.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 HistoryPage {
  19         const DIR_PREV = 0;
  20         const DIR_NEXT = 1;
  21
  22         var $article, $title, $skin;
  23
  24         /**
  25          * Construct a new HistoryPage.
  26          *
  27          * @param Article $article
  28          * @returns nothing
  29          */
  30         function __construct( $article ) {
  31                 global $wgUser;
  32                 $this->article = $article;
  33                 $this->title = $article->getTitle();
  34                 $this->skin = $wgUser->getSkin();
  35                 $this->preCacheMessages();
  36         }
  37
  38         function getArticle() {
  39                 return $this->article;
  40         }
  41
  42         function getTitle() {
  43                 return $this->title;
  44         }
  45
  46         /**
  47          * As we use the same small set of messages in various methods and that
  48          * they are called often, we call them once and save them in $this->message
  49          */
  50         function preCacheMessages() {
  51                 // Precache various messages
  52                 if( !isset( $this->message ) ) {
  53                         $msgs = array( 'cur', 'last', 'rev-delundel', 'pipe-separator' );
  54                         foreach( $msgs as $msg ) {
  55                                 $this->message[$msg] = wfMsgExt( $msg, array( 'escapenoentities') );
  56                         }
  57                 }
  58         }
  59
  60         /**
  61          * Print the history page for an article.
  62          *
  63          * @returns nothing
  64          */
  65         function history() {
  66                 global $wgOut, $wgRequest, $wgScript;
  67
  68                 /*
  69                  * Allow client caching.
  70                  */
  71                 if( $wgOut->checkLastModified( $this->article->getTouched() ) )
  72                         return; // Client cache fresh and headers sent, nothing more to do.
  73
  74                 wfProfileIn( __METHOD__ );
  75
  76                 /*
  77                  * Setup page variables.
  78                  */
  79                 $wgOut->setPageTitle( wfMsg( 'history-title', $this->title->getPrefixedText() ) );
  80                 $wgOut->setPageTitleActionText( wfMsg( 'history_short' ) );
  81                 $wgOut->setArticleFlag( false );
  82                 $wgOut->setArticleRelated( true );
  83                 $wgOut->setRobotPolicy( 'noindex,nofollow' );
  84                 $wgOut->setSyndicated( true );
  85                 $wgOut->setFeedAppendQuery( 'action=history' );
  86                 $wgOut->addScriptFile( 'history.js' );
  87
  88                 $logPage = SpecialPage::getTitleFor( 'Log' );
  89                 $logLink = $this->skin->link(
  90                         $logPage,
  91                         wfMsgHtml( 'viewpagelogs' ),
  92                         array(),
  93                         array( 'page' => $this->title->getPrefixedText() ),
  94                         array( 'known', 'noclasses' )
  95                 );
  96                 $wgOut->setSubtitle( $logLink );
  97
  98                 $feedType = $wgRequest->getVal( 'feed' );
  99                 if( $feedType ) {
 100                         wfProfileOut( __METHOD__ );
 101                         return $this->feed( $feedType );
 102                 }
 103
 104                 /*
 105                  * Fail if article doesn't exist.
 106                  */
 107                 if( !$this->title->exists() ) {
 108                         $wgOut->addWikiMsg( 'nohistory' );
 109                         # show deletion/move log if there is an entry
 110                         LogEventsList::showLogExtract(
 111                                 $wgOut,
 112                                 array( 'delete', 'move' ),
 113                                 $this->title->getPrefixedText(),
 114                                 '',
 115                                 array(  'lim' => 10,
 116                                         'conds' => array( "log_action != 'revision'" ),
 117                                         'showIfEmpty' => false,
 118                                         'msgKey' => array( 'moveddeleted-notice' )
 119                                 )
 120                         );
 121                         wfProfileOut( __METHOD__ );
 122                         return;
 123                 }
 124
 125                 /**
 126                  * Add date selector to quickly get to a certain time
 127                  */
 128                 $year = $wgRequest->getInt( 'year' );
 129                 $month = $wgRequest->getInt( 'month' );
 130                 $tagFilter = $wgRequest->getVal( 'tagfilter' );
 131                 $tagSelector = ChangeTags::buildTagFilterSelector( $tagFilter );
 132
 133                 $action = htmlspecialchars( $wgScript );
 134                 $wgOut->addHTML(
 135                         "<form action=\"$action\" method=\"get\" id=\"mw-history-searchform\">" .
 136                         Xml::fieldset(
 137                                 wfMsg( 'history-fieldset-title' ),
 138                                 false,
 139                                 array( 'id' => 'mw-history-search' )
 140                         ) .
 141                         Xml::hidden( 'title', $this->title->getPrefixedDBKey() ) . "\n" .
 142                         Xml::hidden( 'action', 'history' ) . "\n" .
 143                         xml::dateMenu( $year, $month ) . '&nbsp;' .
 144                         ( $tagSelector ? ( implode( '&nbsp;', $tagSelector ) . '&nbsp;' ) : '' ) .
 145                         Xml::submitButton( wfMsg( 'allpagessubmit' ) ) . "\n" .
 146                         '</fieldset></form>'
 147                 );
 148
 149                 wfRunHooks( 'PageHistoryBeforeList', array( &$this->article ) );
 150
 151                 /**
 152                  * Do the list
 153                  */
 154                 $pager = new HistoryPager( $this, $year, $month, $tagFilter );
 155                 $wgOut->addHTML(
 156                         $pager->getNavigationBar() .
 157                         $pager->getBody() .
 158                         $pager->getNavigationBar()
 159                 );
 160
 161                 wfProfileOut( __METHOD__ );
 162         }
 163
 164         /**
 165          * Fetch an array of revisions, specified by a given limit, offset and
 166          * direction. This is now only used by the feeds. It was previously
 167          * used by the main UI but that's now handled by the pager.
 168          */
 169         function fetchRevisions($limit, $offset, $direction) {
 170                 $dbr = wfGetDB( DB_SLAVE );
 171
 172                 if( $direction == HistoryPage::DIR_PREV )
 173                         list($dirs, $oper) = array("ASC", ">=");
 174                 else /* $direction == HistoryPage::DIR_NEXT */
 175                         list($dirs, $oper) = array("DESC", "<=");
 176
 177                 if( $offset )
 178                         $offsets = array("rev_timestamp $oper '$offset'");
 179                 else
 180                         $offsets = array();
 181
 182                 $page_id = $this->title->getArticleID();
 183
 184                 return $dbr->select( 'revision',
 185                         Revision::selectFields(),
 186                         array_merge(array("rev_page=$page_id"), $offsets),
 187                         __METHOD__,
 188                         array( 'ORDER BY' => "rev_timestamp $dirs",
 189                                 'USE INDEX' => 'page_timestamp', 'LIMIT' => $limit)
 190                 );
 191         }
 192
 193         /**
 194          * Output a subscription feed listing recent edits to this page.
 195          * @param string $type
 196          */
 197         function feed( $type ) {
 198                 global $wgFeedClasses, $wgRequest, $wgFeedLimit;
 199                 if( !FeedUtils::checkFeedOutput($type) ) {
 200                         return;
 201                 }
 202
 203                 $feed = new $wgFeedClasses[$type](
 204                         $this->title->getPrefixedText() . ' - ' .
 205                         wfMsgForContent( 'history-feed-title' ),
 206                         wfMsgForContent( 'history-feed-description' ),
 207                         $this->title->getFullUrl( 'action=history' )
 208                 );
 209
 210                 // Get a limit on number of feed entries. Provide a sane default
 211                 // of 10 if none is defined (but limit to $wgFeedLimit max)
 212                 $limit = $wgRequest->getInt( 'limit', 10 );
 213                 if( $limit > $wgFeedLimit || $limit < 1 ) {
 214                         $limit = 10;
 215                 }
 216                 $items = $this->fetchRevisions($limit, 0, HistoryPage::DIR_NEXT);
 217
 218                 $feed->outHeader();
 219                 if( $items ) {
 220                         foreach( $items as $row ) {
 221                                 $feed->outItem( $this->feedItem( $row ) );
 222                         }
 223                 } else {
 224                         $feed->outItem( $this->feedEmpty() );
 225                 }
 226                 $feed->outFooter();
 227         }
 228
 229         function feedEmpty() {
 230                 global $wgOut;
 231                 return new FeedItem(
 232                         wfMsgForContent( 'nohistory' ),
 233                         $wgOut->parse( wfMsgForContent( 'history-feed-empty' ) ),
 234                         $this->title->getFullUrl(),
 235                         wfTimestamp( TS_MW ),
 236                         '',
 237                         $this->title->getTalkPage()->getFullUrl()
 238                 );
 239         }
 240
 241         /**
 242          * Generate a FeedItem object from a given revision table row
 243          * Borrows Recent Changes' feed generation functions for formatting;
 244          * includes a diff to the previous revision (if any).
 245          *
 246          * @param $row
 247          * @return FeedItem
 248          */
 249         function feedItem( $row ) {
 250                 $rev = new Revision( $row );
 251                 $rev->setTitle( $this->title );
 252                 $text = FeedUtils::formatDiffRow(
 253                         $this->title,
 254                         $this->title->getPreviousRevisionID( $rev->getId() ),
 255                         $rev->getId(),
 256                         $rev->getTimestamp(),
 257                         $rev->getComment()
 258                 );
 259                 if( $rev->getComment() == '' ) {
 260                         global $wgContLang;
 261                         $title = wfMsgForContent( 'history-feed-item-nocomment',
 262                                 $rev->getUserText(),
 263                                 $wgContLang->timeanddate( $rev->getTimestamp() ),
 264                                 $wgContLang->date( $rev->getTimestamp() ),
 265                                 $wgContLang->time( $rev->getTimestamp() )
 266                         );
 267                 } else {
 268                         $title = $rev->getUserText() .
 269                         wfMsgForContent( 'colon-separator' ) .
 270                         FeedItem::stripComment( $rev->getComment() );
 271                 }
 272                 return new FeedItem(
 273                         $title,
 274                         $text,
 275                         $this->title->getFullUrl( 'diff=' . $rev->getId() . '&oldid=prev' ),
 276                         $rev->getTimestamp(),
 277                         $rev->getUserText(),
 278                         $this->title->getTalkPage()->getFullUrl()
 279                 );
 280         }
 281 }
 282
 283 /**
 284  * @ingroup Pager
 285  */
 286 class HistoryPager extends ReverseChronologicalPager {
 287         public $lastRow = false, $counter, $historyPage, $title, $buttons;
 288         protected $oldIdChecked;
 289
 290         function __construct( $historyPage, $year='', $month='', $tagFilter = '' ) {
 291                 parent::__construct();
 292                 $this->historyPage = $historyPage;
 293                 $this->title = $this->historyPage->title;
 294                 $this->tagFilter = $tagFilter;
 295                 $this->getDateCond( $year, $month );
 296         }
 297
 298         // For hook compatibility...
 299         function getArticle() {
 300                 return $this->historyPage->getArticle();
 301         }
 302
 303         function getQueryInfo() {
 304                 $queryInfo = array(
 305                         'tables'  => array('revision'),
 306                         'fields'  => array_merge( Revision::selectFields(), array('ts_tags') ),
 307                         'conds'   => array('rev_page' => $this->historyPage->title->getArticleID() ),
 308                         'options' => array( 'USE INDEX' => array('revision' => 'page_timestamp') ),
 309                         'join_conds' => array( 'tag_summary' => array( 'LEFT JOIN', 'ts_rev_id=rev_id' ) ),
 310                 );
 311                 ChangeTags::modifyDisplayQuery(
 312                         $queryInfo['tables'],
 313                         $queryInfo['fields'],
 314                         $queryInfo['conds'],
 315                         $queryInfo['join_conds'],
 316                         $queryInfo['options'],
 317                         $this->tagFilter
 318                 );
 319                 wfRunHooks( 'PageHistoryPager::getQueryInfo', array( &$this, &$queryInfo ) );
 320                 return $queryInfo;
 321         }
 322
 323         function getIndexField() {
 324                 return 'rev_timestamp';
 325         }
 326
 327         function formatRow( $row ) {
 328                 if( $this->lastRow ) {
 329                         $latest = ($this->counter == 1 && $this->mIsFirst);
 330                         $firstInList = $this->counter == 1;
 331                         $s = $this->historyLine( $this->lastRow, $row, $this->counter++,
 332                                 $this->title->getNotificationTimestamp(), $latest, $firstInList );
 333                 } else {
 334                         $s = '';
 335                 }
 336                 $this->lastRow = $row;
 337                 return $s;
 338         }
 339
 340         /**
 341          * Creates begin of history list with a submit button
 342          *
 343          * @return string HTML output
 344          */
 345         function getStartBody() {
 346                 global $wgScript, $wgEnableHtmlDiff, $wgUser, $wgOut, $wgContLang;
 347                 $this->lastRow = false;
 348                 $this->counter = 1;
 349                 $this->oldIdChecked = 0;
 350
 351                 $wgOut->wrapWikiMsg( "<div class='mw-history-legend'>\n$1</div>", 'histlegend' );
 352                 $s = Xml::openElement( 'form', array( 'action' => $wgScript,
 353                         'id' => 'mw-history-compare' ) ) . "\n";
 354                 $s .= Xml::hidden( 'title', $this->title->getPrefixedDbKey() ) . "\n";
 355                 $s .= Xml::hidden( 'action', 'historysubmit' ) . "\n";
 356
 357                 $this->buttons = '<div>';
 358                 if( $wgUser->isAllowed('deleterevision') ) {
 359                         $float = $wgContLang->alignEnd();
 360                         # Note bug #20966, <button> is non-standard in IE<8
 361                         $this->buttons .= Xml::element( 'button',
 362                                 array(
 363                                         'type' => 'submit',
 364                                         'name' => 'revisiondelete',
 365                                         'value' => '1',
 366                                         'style' => "float: $float;",
 367                                         'class' => 'mw-history-revisiondelete-button',
 368                                 ),
 369                                 wfMsg( 'showhideselectedversions' )
 370                         ) . "\n";
 371                 }
 372                 if( $wgEnableHtmlDiff ) {
 373                         $this->buttons .= Xml::element( 'button',
 374                                 array(
 375                                         'type'      => 'submit',
 376                                         'name'      => 'htmldiff',
 377                                         'value'     => '1',
 378                                         'class'     => 'historysubmit',
 379                                         'accesskey' => wfMsg( 'accesskey-visualcomparison' ),
 380                                         'title'     => wfMsg( 'tooltip-compareselectedversions' ),
 381                                 ),
 382                                 wfMsg( 'visualcomparison')
 383                         ) . "\n";
 384                         $this->buttons .= $this->submitButton( wfMsg( 'wikicodecomparison'),
 385                                 array(
 386                                         'class'     => 'historysubmit',
 387                                         'accesskey' => wfMsg( 'accesskey-compareselectedversions' ),
 388                                         'title'     => wfMsg( 'tooltip-compareselectedversions' ),
 389                                 )
 390                         ) . "\n";
 391                 } else {
 392                         $this->buttons .= $this->submitButton( wfMsg( 'compareselectedversions'),
 393                                 array(
 394                                         'class'     => 'historysubmit',
 395                                         'accesskey' => wfMsg( 'accesskey-compareselectedversions' ),
 396                                         'title'     => wfMsg( 'tooltip-compareselectedversions' ),
 397                                 )
 398                         ) . "\n";
 399                 }
 400                 $this->buttons .= '</div>';
 401                 $s .= $this->buttons . '<ul id="pagehistory">' . "\n";
 402                 return $s;
 403         }
 404
 405         function getEndBody() {
 406                 if( $this->lastRow ) {
 407                         $latest = $this->counter == 1 && $this->mIsFirst;
 408                         $firstInList = $this->counter == 1;
 409                         if( $this->mIsBackwards ) {
 410                                 # Next row is unknown, but for UI reasons, probably exists if an offset has been specified
 411                                 if( $this->mOffset == '' ) {
 412                                         $next = null;
 413                                 } else {
 414                                         $next = 'unknown';
 415                                 }
 416                         } else {
 417                                 # The next row is the past-the-end row
 418                                 $next = $this->mPastTheEndRow;
 419                         }
 420                         $s = $this->historyLine( $this->lastRow, $next, $this->counter++,
 421                                 $this->title->getNotificationTimestamp(), $latest, $firstInList );
 422                 } else {
 423                         $s = '';
 424                 }
 425                 $s .= "</ul>\n";
 426                 $s .= $this->buttons;
 427                 $s .= '</form>';
 428                 return $s;
 429         }
 430
 431         /**
 432          * Creates a submit button
 433          *
 434          * @param array $attributes attributes
 435          * @return string HTML output for the submit button
 436          */
 437         function submitButton($message, $attributes = array() ) {
 438                 # Disable submit button if history has 1 revision only
 439                 if( $this->getNumRows() > 1 ) {
 440                         return Xml::submitButton( $message , $attributes );
 441                 } else {
 442                         return '';
 443                 }
 444         }
 445
 446         /**
 447          * Returns a row from the history printout.
 448          *
 449          * @todo document some more, and maybe clean up the code (some params redundant?)
 450          *
 451          * @param Row $row The database row corresponding to the previous line.
 452          * @param mixed $next The database row corresponding to the next line.
 453          * @param int $counter Apparently a counter of what row number we're at, counted from the top row = 1.
 454          * @param $notificationtimestamp
 455          * @param bool $latest Whether this row corresponds to the page's latest revision.
 456          * @param bool $firstInList Whether this row corresponds to the first displayed on this history page.
 457          * @return string HTML output for the row
 458          */
 459         function historyLine( $row, $next, $counter = '', $notificationtimestamp = false,
 460                 $latest = false, $firstInList = false )
 461         {
 462                 global $wgUser, $wgLang;
 463                 $rev = new Revision( $row );
 464                 $rev->setTitle( $this->title );
 465
 466                 $curlink = $this->curLink( $rev, $latest );
 467                 $lastlink = $this->lastLink( $rev, $next, $counter );
 468                 $diffButtons = $this->diffButtons( $rev, $firstInList, $counter );
 469                 $histLinks = Html::rawElement(
 470                                 'span',
 471                                 array( 'class' => 'mw-history-histlinks' ),
 472                                 '(' . $curlink . $this->historyPage->message['pipe-separator'] . $lastlink . ') '
 473                 );
 474                 $s = $histLinks . $diffButtons;
 475
 476                 $link = $this->revLink( $rev );
 477                 $classes = array();
 478
 479                 if( $wgUser->isAllowed( 'deleterevision' ) ) {
 480                         // Don't show useless link to people who cannot hide revisions
 481                         if( !$rev->getVisibility() && !$wgUser->isAllowed( 'deleterevision' ) ) {
 482                                 $del = Xml::check( 'deleterevisions', false, array('class' => 'mw-revdelundel-hidden') );
 483                         // If revision was hidden from sysops
 484                         } else if( !$rev->userCan( Revision::DELETED_RESTRICTED ) ) {
 485                                 $del = Xml::check( 'deleterevisions', false, array('disabled' => 'disabled') );
 486                         // Otherwise, show the link...
 487                         } else {
 488                                 $id = $rev->getId();
 489                                 $del = Xml::check( 'showhiderevisions', false, array( 'name' => "ids[$id]" ) );
 490                         }
 491                         $s .= " $del ";
 492                 }
 493
 494                 $s .= " $link";
 495                 $s .= " <span class='history-user'>" . $this->getSkin()->revUserTools( $rev, true ) . "</span>";
 496
 497                 if( $rev->isMinor() ) {
 498                         $s .= ' ' . ChangesList::flag( 'minor' );
 499                 }
 500
 501                 if( !is_null( $size = $rev->getSize() ) && !$rev->isDeleted( Revision::DELETED_TEXT ) ) {
 502                         $s .= ' ' . $this->getSkin()->formatRevisionSize( $size );
 503                 }
 504
 505                 $s .= $this->getSkin()->revComment( $rev, false, true );
 506
 507                 if( $notificationtimestamp && ($row->rev_timestamp >= $notificationtimestamp) ) {
 508                         $s .= ' <span class="updatedmarker">' .  wfMsgHtml( 'updatedmarker' ) . '</span>';
 509                 }
 510
 511                 $tools = array();
 512
 513                 # Rollback and undo links
 514                 if( !is_null( $next ) && is_object( $next ) ) {
 515                         if( $latest && $this->title->userCan( 'rollback' ) && $this->title->userCan( 'edit' ) ) {
 516                                 $tools[] = '<span class="mw-rollback-link">'.
 517                                         $this->getSkin()->buildRollbackLink( $rev ).'</span>';
 518                         }
 519
 520                         if( $this->title->quickUserCan( 'edit' )
 521                                 && !$rev->isDeleted( Revision::DELETED_TEXT )
 522                                 && !$next->rev_deleted & Revision::DELETED_TEXT )
 523                         {
 524                                 # Create undo tooltip for the first (=latest) line only
 525                                 $undoTooltip = $latest
 526                                         ? array( 'title' => wfMsg( 'tooltip-undo' ) )
 527                                         : array();
 528                                 $undolink = $this->getSkin()->link(
 529                                         $this->title,
 530                                         wfMsgHtml( 'editundo' ),
 531                                         $undoTooltip,
 532                                         array(
 533                                                 'action' => 'edit',
 534                                                 'undoafter' => $next->rev_id,
 535                                                 'undo' => $rev->getId()
 536                                         ),
 537                                         array( 'known', 'noclasses' )
 538                                 );
 539                                 $tools[] = "<span class=\"mw-history-undo\">{$undolink}</span>";
 540                         }
 541                 }
 542
 543                 if( $tools ) {
 544                         $s .= ' (' . $wgLang->pipeList( $tools ) . ')';
 545                 }
 546
 547                 # Tags
 548                 list($tagSummary, $newClasses) = ChangeTags::formatSummaryRow( $row->ts_tags, 'history' );
 549                 $classes = array_merge( $classes, $newClasses );
 550                 $s .= " $tagSummary";
 551
 552                 wfRunHooks( 'PageHistoryLineEnding', array( $this, &$row , &$s ) );
 553
 554                 $attribs = array();
 555                 if ( $classes ) {
 556                         $attribs['class'] = implode( ' ', $classes );
 557                 }
 558
 559                 return Xml::tags( 'li', $attribs, $s ) . "\n";
 560         }
 561
 562         /**
 563          * Create a link to view this revision of the page
 564          * @param Revision $rev
 565          * @returns string
 566          */
 567         function revLink( $rev ) {
 568                 global $wgLang;
 569                 $date = $wgLang->timeanddate( wfTimestamp(TS_MW, $rev->getTimestamp()), true );
 570                 $date = htmlspecialchars( $date );
 571                 if( !$rev->isDeleted( Revision::DELETED_TEXT ) ) {
 572                         $link = $this->getSkin()->link(
 573                                 $this->title,
 574                                 $date,
 575                                 array(),
 576                                 array( 'oldid' => $rev->getId() ),
 577                                 array( 'known', 'noclasses' )
 578                         );
 579                 } else {
 580                         $link = "<span class=\"history-deleted\">$date</span>";
 581                 }
 582                 return $link;
 583         }
 584
 585         /**
 586          * Create a diff-to-current link for this revision for this page
 587          * @param Revision $rev
 588          * @param Bool $latest, this is the latest revision of the page?
 589          * @returns string
 590          */
 591         function curLink( $rev, $latest ) {
 592                 $cur = $this->historyPage->message['cur'];
 593                 if( $latest || !$rev->userCan( Revision::DELETED_TEXT ) ) {
 594                         return $cur;
 595                 } else {
 596                         return $this->getSkin()->link(
 597                                 $this->title,
 598                                 $cur,
 599                                 array(),
 600                                 array(
 601                                         'diff' => $this->title->getLatestRevID(),
 602                                         'oldid' => $rev->getId()
 603                                 ),
 604                                 array( 'known', 'noclasses' )
 605                         );
 606                 }
 607         }
 608
 609         /**
 610          * Create a diff-to-previous link for this revision for this page.
 611          * @param Revision $prevRev, the previous revision
 612          * @param mixed $next, the newer revision
 613          * @param int $counter, what row on the history list this is
 614          * @returns string
 615          */
 616         function lastLink( $prevRev, $next, $counter ) {
 617                 $last = $this->historyPage->message['last'];
 618                 # $next may either be a Row, null, or "unkown"
 619                 $nextRev = is_object($next) ? new Revision( $next ) : $next;
 620                 if( is_null($next) ) {
 621                         # Probably no next row
 622                         return $last;
 623                 } elseif( $next === 'unknown' ) {
 624                         # Next row probably exists but is unknown, use an oldid=prev link
 625                         return $this->getSkin()->link(
 626                                 $this->title,
 627                                 $last,
 628                                 array(),
 629                                 array(
 630                                         'diff' => $prevRev->getId(),
 631                                         'oldid' => 'prev'
 632                                 ),
 633                                 array( 'known', 'noclasses' )
 634                         );
 635                 } elseif( !$prevRev->userCan(Revision::DELETED_TEXT) || !$nextRev->userCan(Revision::DELETED_TEXT) ) {
 636                         return $last;
 637                 } else {
 638                         return $this->getSkin()->link(
 639                                 $this->title,
 640                                 $last,
 641                                 array(),
 642                                 array(
 643                                         'diff' => $prevRev->getId(),
 644                                         'oldid' => $next->rev_id
 645                                 ),
 646                                 array( 'known', 'noclasses' )
 647                         );
 648                 }
 649         }
 650
 651         /**
 652          * Create radio buttons for page history
 653          *
 654          * @param object $rev Revision
 655          * @param bool $firstInList Is this version the first one?
 656          * @param int $counter A counter of what row number we're at, counted from the top row = 1.
 657          * @return string HTML output for the radio buttons
 658          */
 659         function diffButtons( $rev, $firstInList, $counter ) {
 660                 if( $this->getNumRows() > 1 ) {
 661                         $id = $rev->getId();
 662                         $radio = array( 'type'  => 'radio', 'value' => $id );
 663                         /** @todo: move title texts to javascript */
 664                         if( $firstInList ) {
 665                                 $first = Xml::element( 'input',
 666                                         array_merge( $radio, array(
 667                                                 'style' => 'visibility:hidden',
 668                                                 'name'  => 'oldid',
 669                                                 'id' => 'mw-oldid-null' ) )
 670                                 );
 671                                 $checkmark = array( 'checked' => 'checked' );
 672                         } else {
 673                                 # Check ility of old revisions
 674                                 if( !$rev->userCan( Revision::DELETED_TEXT ) ) {
 675                                         $radio['disabled'] = 'disabled';
 676                                         $checkmark = array(); // We will check the next possible one
 677                                 } else if( $counter == 2 || !$this->oldIdChecked ) {
 678                                         $checkmark = array( 'checked' => 'checked' );
 679                                         $this->oldIdChecked = $id;
 680                                 } else {
 681                                         $checkmark = array();
 682                                 }
 683                                 $first = Xml::element( 'input',
 684                                         array_merge( $radio, $checkmark, array(
 685                                                 'name'  => 'oldid',
 686                                                 'id' => "mw-oldid-$id" ) ) );
 687                                 $checkmark = array();
 688                         }
 689                         $second = Xml::element( 'input',
 690                                 array_merge( $radio, $checkmark, array(
 691                                         'name'  => 'diff',
 692                                         'id' => "mw-diff-$id" ) ) );
 693                         return $first . $second;
 694                 } else {
 695                         return '';
 696                 }
 697         }
 698 }
 699
 700 /**
 701  * Backwards-compatibility aliases
 702  */
 703 class PageHistory extends HistoryPage {}
 704 class PageHistoryPager extends HistoryPager {}