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' );
  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                 } else {
 265                         $title = $rev->getUserText() .
 266                         wfMsgForContent( 'colon-separator' ) .
 267                         FeedItem::stripComment( $rev->getComment() );
 268                 }
 269                 return new FeedItem(
 270                         $title,
 271                         $text,
 272                         $this->title->getFullUrl( 'diff=' . $rev->getId() . '&oldid=prev' ),
 273                         $rev->getTimestamp(),
 274                         $rev->getUserText(),
 275                         $this->title->getTalkPage()->getFullUrl()
 276                 );
 277         }
 278 }
 279
 280 /**
 281  * @ingroup Pager
 282  */
 283 class HistoryPager extends ReverseChronologicalPager {
 284         public $lastRow = false, $counter, $historyPage, $title, $buttons;
 285         protected $oldIdChecked;
 286
 287         function __construct( $historyPage, $year='', $month='', $tagFilter = '' ) {
 288                 parent::__construct();
 289                 $this->historyPage = $historyPage;
 290                 $this->title = $this->historyPage->title;
 291                 $this->tagFilter = $tagFilter;
 292                 $this->getDateCond( $year, $month );
 293         }
 294
 295         // For hook compatibility...
 296         function getArticle() {
 297                 return $this->historyPage->getArticle();
 298         }
 299
 300         function getQueryInfo() {
 301                 $queryInfo = array(
 302                         'tables'  => array('revision'),
 303                         'fields'  => array_merge( Revision::selectFields(), array('ts_tags') ),
 304                         'conds'   => array('rev_page' => $this->historyPage->title->getArticleID() ),
 305                         'options' => array( 'USE INDEX' => array('revision' => 'page_timestamp') ),
 306                         'join_conds' => array( 'tag_summary' => array( 'LEFT JOIN', 'ts_rev_id=rev_id' ) ),
 307                 );
 308                 ChangeTags::modifyDisplayQuery(
 309                         $queryInfo['tables'],
 310                         $queryInfo['fields'],
 311                         $queryInfo['conds'],
 312                         $queryInfo['join_conds'],
 313                         $queryInfo['options'],
 314                         $this->tagFilter
 315                 );
 316                 wfRunHooks( 'PageHistoryPager::getQueryInfo', array( &$this, &$queryInfo ) );
 317                 return $queryInfo;
 318         }
 319
 320         function getIndexField() {
 321                 return 'rev_timestamp';
 322         }
 323
 324         function formatRow( $row ) {
 325                 if( $this->lastRow ) {
 326                         $latest = ($this->counter == 1 && $this->mIsFirst);
 327                         $firstInList = $this->counter == 1;
 328                         $s = $this->historyLine( $this->lastRow, $row, $this->counter++,
 329                                 $this->title->getNotificationTimestamp(), $latest, $firstInList );
 330                 } else {
 331                         $s = '';
 332                 }
 333                 $this->lastRow = $row;
 334                 return $s;
 335         }
 336
 337         /**
 338          * Creates begin of history list with a submit button
 339          *
 340          * @return string HTML output
 341          */
 342         function getStartBody() {
 343                 global $wgScript, $wgEnableHtmlDiff, $wgUser, $wgOut, $wgContLang;
 344                 $this->lastRow = false;
 345                 $this->counter = 1;
 346                 $this->oldIdChecked = 0;
 347
 348                 $wgOut->wrapWikiMsg( "<div class='mw-history-legend'>\n$1</div>", 'histlegend' );
 349                 $s = Xml::openElement( 'form', array( 'action' => $wgScript,
 350                         'id' => 'mw-history-compare' ) ) . "\n";
 351                 $s .= Xml::hidden( 'title', $this->title->getPrefixedDbKey() ) . "\n";
 352
 353                 $this->buttons = '<div>';
 354                 if( $wgUser->isAllowed('deletedhistory') ) {
 355                         $float = $wgContLang->isRTL() ? 'left' : 'right';
 356                         $this->buttons .= Xml::element( 'button',
 357                                 array(
 358                                         'type' => 'submit',
 359                                         'name' => 'action',
 360                                         'value' => 'revisiondelete',
 361                                         'style' => "float: $float;",
 362                                         'class' => 'mw-history-revisiondelete-button',
 363                                 ),
 364                                 wfMsg( 'showhideselectedversions' )
 365                         ) . "\n";
 366                 }
 367                 if( $wgEnableHtmlDiff ) {
 368                         $this->buttons .= Xml::element( 'button',
 369                                 array(
 370                                         'type'      => 'submit',
 371                                         'name'      => 'htmldiff',
 372                                         'value'     => '1',
 373                                         'class'     => 'historysubmit',
 374                                         'accesskey' => wfMsg( 'accesskey-visualcomparison' ),
 375                                         'title'     => wfMsg( 'tooltip-compareselectedversions' ),
 376                                 ),
 377                                 wfMsg( 'visualcomparison')
 378                         ) . "\n";
 379                         $this->buttons .= $this->submitButton( wfMsg( 'wikicodecomparison'),
 380                                 array(
 381                                         'class'     => 'historysubmit',
 382                                         'accesskey' => wfMsg( 'accesskey-compareselectedversions' ),
 383                                         'title'     => wfMsg( 'tooltip-compareselectedversions' ),
 384                                 )
 385                         ) . "\n";
 386                 } else {
 387                         $this->buttons .= $this->submitButton( wfMsg( 'compareselectedversions'),
 388                                 array(
 389                                         'class'     => 'historysubmit',
 390                                         'accesskey' => wfMsg( 'accesskey-compareselectedversions' ),
 391                                         'title'     => wfMsg( 'tooltip-compareselectedversions' ),
 392                                 )
 393                         ) . "\n";
 394                 }
 395                 $this->buttons .= '</div>';
 396                 $s .= $this->buttons . '<ul id="pagehistory">' . "\n";
 397                 return $s;
 398         }
 399
 400         function getEndBody() {
 401                 if( $this->lastRow ) {
 402                         $latest = $this->counter == 1 && $this->mIsFirst;
 403                         $firstInList = $this->counter == 1;
 404                         if( $this->mIsBackwards ) {
 405                                 # Next row is unknown, but for UI reasons, probably exists if an offset has been specified
 406                                 if( $this->mOffset == '' ) {
 407                                         $next = null;
 408                                 } else {
 409                                         $next = 'unknown';
 410                                 }
 411                         } else {
 412                                 # The next row is the past-the-end row
 413                                 $next = $this->mPastTheEndRow;
 414                         }
 415                         $s = $this->historyLine( $this->lastRow, $next, $this->counter++,
 416                                 $this->title->getNotificationTimestamp(), $latest, $firstInList );
 417                 } else {
 418                         $s = '';
 419                 }
 420                 $s .= "</ul>\n";
 421                 $s .= $this->buttons;
 422                 $s .= '</form>';
 423                 return $s;
 424         }
 425
 426         /**
 427          * Creates a submit button
 428          *
 429          * @param array $attributes attributes
 430          * @return string HTML output for the submit button
 431          */
 432         function submitButton($message, $attributes = array() ) {
 433                 # Disable submit button if history has 1 revision only
 434                 if( $this->getNumRows() > 1 ) {
 435                         return Xml::submitButton( $message , $attributes );
 436                 } else {
 437                         return '';
 438                 }
 439         }
 440
 441         /**
 442          * Returns a row from the history printout.
 443          *
 444          * @todo document some more, and maybe clean up the code (some params redundant?)
 445          *
 446          * @param Row $row The database row corresponding to the previous line.
 447          * @param mixed $next The database row corresponding to the next line.
 448          * @param int $counter Apparently a counter of what row number we're at, counted from the top row = 1.
 449          * @param $notificationtimestamp
 450          * @param bool $latest Whether this row corresponds to the page's latest revision.
 451          * @param bool $firstInList Whether this row corresponds to the first displayed on this history page.
 452          * @return string HTML output for the row
 453          */
 454         function historyLine( $row, $next, $counter = '', $notificationtimestamp = false,
 455                 $latest = false, $firstInList = false )
 456         {
 457                 global $wgUser, $wgLang;
 458                 $rev = new Revision( $row );
 459                 $rev->setTitle( $this->title );
 460
 461                 $curlink = $this->curLink( $rev, $latest );
 462                 $lastlink = $this->lastLink( $rev, $next, $counter );
 463                 $diffButtons = $this->diffButtons( $rev, $firstInList, $counter );
 464                 $link = $this->revLink( $rev );
 465                 $classes = array();
 466
 467                 $s = "($curlink) ($lastlink) $diffButtons";
 468
 469                 if( $wgUser->isAllowed( 'deletedhistory' ) ) {
 470                         // Don't show useless link to people who cannot hide revisions
 471                         if( !$rev->getVisibility() && !$wgUser->isAllowed( 'deleterevision' ) ) {
 472                                 $del = Xml::check( 'deleterevisions', false, array('class' => 'mw-revdelundel-hidden') );
 473                         // If revision was hidden from sysops
 474                         } else if( !$rev->userCan( Revision::DELETED_RESTRICTED ) ) {
 475                                 $del = Xml::check( 'deleterevisions', false, array('disabled' => 'disabled') );
 476                         // Otherwise, show the link...
 477                         } else {
 478                                 $id = $rev->getId();
 479                                 $del = Xml::check( 'showhiderevisions', false, array( 'name' => "ids[$id]" ) );
 480                         }
 481                         $s .= " $del ";
 482                 }
 483
 484                 $s .= " $link";
 485                 $s .= " <span class='history-user'>" . $this->getSkin()->revUserTools( $rev, true ) . "</span>";
 486
 487                 if( $rev->isMinor() ) {
 488                         $s .= ' ' . ChangesList::flag( 'minor' );
 489                 }
 490
 491                 if( !is_null( $size = $rev->getSize() ) && !$rev->isDeleted( Revision::DELETED_TEXT ) ) {
 492                         $s .= ' ' . $this->getSkin()->formatRevisionSize( $size );
 493                 }
 494
 495                 $s .= $this->getSkin()->revComment( $rev, false, true );
 496
 497                 if( $notificationtimestamp && ($row->rev_timestamp >= $notificationtimestamp) ) {
 498                         $s .= ' <span class="updatedmarker">' .  wfMsgHtml( 'updatedmarker' ) . '</span>';
 499                 }
 500
 501                 $tools = array();
 502
 503                 # Rollback and undo links
 504                 if( !is_null( $next ) && is_object( $next ) ) {
 505                         if( $latest && $this->title->userCan( 'rollback' ) && $this->title->userCan( 'edit' ) ) {
 506                                 $tools[] = '<span class="mw-rollback-link">'.
 507                                         $this->getSkin()->buildRollbackLink( $rev ).'</span>';
 508                         }
 509
 510                         if( $this->title->quickUserCan( 'edit' )
 511                                 && !$rev->isDeleted( Revision::DELETED_TEXT )
 512                                 && !$next->rev_deleted & Revision::DELETED_TEXT )
 513                         {
 514                                 # Create undo tooltip for the first (=latest) line only
 515                                 $undoTooltip = $latest
 516                                         ? array( 'title' => wfMsg( 'tooltip-undo' ) )
 517                                         : array();
 518                                 $undolink = $this->getSkin()->link(
 519                                         $this->title,
 520                                         wfMsgHtml( 'editundo' ),
 521                                         $undoTooltip,
 522                                         array(
 523                                                 'action' => 'edit',
 524                                                 'undoafter' => $next->rev_id,
 525                                                 'undo' => $rev->getId()
 526                                         ),
 527                                         array( 'known', 'noclasses' )
 528                                 );
 529                                 $tools[] = "<span class=\"mw-history-undo\">{$undolink}</span>";
 530                         }
 531                 }
 532
 533                 if( $tools ) {
 534                         $s .= ' (' . $wgLang->pipeList( $tools ) . ')';
 535                 }
 536
 537                 # Tags
 538                 list($tagSummary, $newClasses) = ChangeTags::formatSummaryRow( $row->ts_tags, 'history' );
 539                 $classes = array_merge( $classes, $newClasses );
 540                 $s .= " $tagSummary";
 541
 542                 wfRunHooks( 'PageHistoryLineEnding', array( $this, &$row , &$s ) );
 543
 544                 $attribs = array();
 545                 if ( $classes ) {
 546                         $attribs['class'] = implode( ' ', $classes );
 547                 }
 548
 549                 return Xml::tags( 'li', $attribs, $s ) . "\n";
 550         }
 551
 552         /**
 553          * Create a link to view this revision of the page
 554          * @param Revision $rev
 555          * @returns string
 556          */
 557         function revLink( $rev ) {
 558                 global $wgLang;
 559                 $date = $wgLang->timeanddate( wfTimestamp(TS_MW, $rev->getTimestamp()), true );
 560                 $date = htmlspecialchars( $date );
 561                 if( !$rev->isDeleted( Revision::DELETED_TEXT ) ) {
 562                         $link = $this->getSkin()->link(
 563                                 $this->title,
 564                                 $date,
 565                                 array(),
 566                                 array( 'oldid' => $rev->getId() ),
 567                                 array( 'known', 'noclasses' )
 568                         );
 569                 } else {
 570                         $link = "<span class=\"history-deleted\">$date</span>";
 571                 }
 572                 return $link;
 573         }
 574
 575         /**
 576          * Create a diff-to-current link for this revision for this page
 577          * @param Revision $rev
 578          * @param Bool $latest, this is the latest revision of the page?
 579          * @returns string
 580          */
 581         function curLink( $rev, $latest ) {
 582                 $cur = $this->historyPage->message['cur'];
 583                 if( $latest || !$rev->userCan( Revision::DELETED_TEXT ) ) {
 584                         return $cur;
 585                 } else {
 586                         return $this->getSkin()->link(
 587                                 $this->title,
 588                                 $cur,
 589                                 array(),
 590                                 array(
 591                                         'diff' => $this->title->getLatestRevID(),
 592                                         'oldid' => $rev->getId()
 593                                 ),
 594                                 array( 'known', 'noclasses' )
 595                         );
 596                 }
 597         }
 598
 599         /**
 600          * Create a diff-to-previous link for this revision for this page.
 601          * @param Revision $prevRev, the previous revision
 602          * @param mixed $next, the newer revision
 603          * @param int $counter, what row on the history list this is
 604          * @returns string
 605          */
 606         function lastLink( $prevRev, $next, $counter ) {
 607                 $last = $this->historyPage->message['last'];
 608                 # $next may either be a Row, null, or "unkown"
 609                 $nextRev = is_object($next) ? new Revision( $next ) : $next;
 610                 if( is_null($next) ) {
 611                         # Probably no next row
 612                         return $last;
 613                 } elseif( $next === 'unknown' ) {
 614                         # Next row probably exists but is unknown, use an oldid=prev link
 615                         return $this->getSkin()->link(
 616                                 $this->title,
 617                                 $last,
 618                                 array(),
 619                                 array(
 620                                         'diff' => $prevRev->getId(),
 621                                         'oldid' => 'prev'
 622                                 ),
 623                                 array( 'known', 'noclasses' )
 624                         );
 625                 } elseif( !$prevRev->userCan(Revision::DELETED_TEXT) || !$nextRev->userCan(Revision::DELETED_TEXT) ) {
 626                         return $last;
 627                 } else {
 628                         return $this->getSkin()->link(
 629                                 $this->title,
 630                                 $last,
 631                                 array(),
 632                                 array(
 633                                         'diff' => $prevRev->getId(),
 634                                         'oldid' => $next->rev_id
 635                                 ),
 636                                 array( 'known', 'noclasses' )
 637                         );
 638                 }
 639         }
 640
 641         /**
 642          * Create radio buttons for page history
 643          *
 644          * @param object $rev Revision
 645          * @param bool $firstInList Is this version the first one?
 646          * @param int $counter A counter of what row number we're at, counted from the top row = 1.
 647          * @return string HTML output for the radio buttons
 648          */
 649         function diffButtons( $rev, $firstInList, $counter ) {
 650                 if( $this->getNumRows() > 1 ) {
 651                         $id = $rev->getId();
 652                         $radio = array( 'type'  => 'radio', 'value' => $id );
 653                         /** @todo: move title texts to javascript */
 654                         if( $firstInList ) {
 655                                 $first = Xml::element( 'input',
 656                                         array_merge( $radio, array(
 657                                                 'style' => 'visibility:hidden',
 658                                                 'name'  => 'oldid',
 659                                                 'id' => 'mw-oldid-null' ) )
 660                                 );
 661                                 $checkmark = array( 'checked' => 'checked' );
 662                         } else {
 663                                 # Check visibility of old revisions
 664                                 if( !$rev->userCan( Revision::DELETED_TEXT ) ) {
 665                                         $radio['disabled'] = 'disabled';
 666                                         $checkmark = array(); // We will check the next possible one
 667                                 } else if( $counter == 2 || !$this->oldIdChecked ) {
 668                                         $checkmark = array( 'checked' => 'checked' );
 669                                         $this->oldIdChecked = $id;
 670                                 } else {
 671                                         $checkmark = array();
 672                                 }
 673                                 $first = Xml::element( 'input',
 674                                         array_merge( $radio, $checkmark, array(
 675                                                 'name'  => 'oldid',
 676                                                 'id' => "mw-oldid-$id" ) ) );
 677                                 $checkmark = array();
 678                         }
 679                         $second = Xml::element( 'input',
 680                                 array_merge( $radio, $checkmark, array(
 681                                         'name'  => 'diff',
 682                                         'id' => "mw-diff-$id" ) ) );
 683                         return $first . $second;
 684                 } else {
 685                         return '';
 686                 }
 687         }
 688 }
 689
 690 /**
 691  * Backwards-compatibility aliases
 692  */
 693 class PageHistory extends HistoryPage {}
 694 class PageHistoryPager extends HistoryPager {}