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          */
  29         function __construct( $article ) {
  30                 global $wgUser;
  31                 $this->article = $article;
  32                 $this->title = $article->getTitle();
  33                 $this->skin = $wgUser->getSkin();
  34                 $this->preCacheMessages();
  35         }
  36
  37         function getArticle() {
  38                 return $this->article;
  39         }
  40
  41         function getTitle() {
  42                 return $this->title;
  43         }
  44
  45         /**
  46          * As we use the same small set of messages in various methods and that
  47          * they are called often, we call them once and save them in $this->message
  48          */
  49         function preCacheMessages() {
  50                 // Precache various messages
  51                 if( !isset( $this->message ) ) {
  52                         $msgs = array( 'cur', 'last', 'pipe-separator' );
  53                         foreach( $msgs as $msg ) {
  54                                 $this->message[$msg] = wfMsgExt( $msg, array( 'escapenoentities') );
  55                         }
  56                 }
  57         }
  58
  59         /**
  60          * Print the history page for an article.
  61          * @return nothing
  62          */
  63         function history() {
  64                 global $wgOut, $wgRequest, $wgScript;
  65
  66                 /*
  67                  * Allow client caching.
  68                  */
  69                 if( $wgOut->checkLastModified( $this->article->getTouched() ) )
  70                         return; // Client cache fresh and headers sent, nothing more to do.
  71
  72                 wfProfileIn( __METHOD__ );
  73
  74                 /*
  75                  * Setup page variables.
  76                  */
  77                 $wgOut->setPageTitle( wfMsg( 'history-title', $this->title->getPrefixedText() ) );
  78                 $wgOut->setPageTitleActionText( wfMsg( 'history_short' ) );
  79                 $wgOut->setArticleFlag( false );
  80                 $wgOut->setArticleRelated( true );
  81                 $wgOut->setRobotPolicy( 'noindex,nofollow' );
  82                 $wgOut->setSyndicated( true );
  83                 $wgOut->setFeedAppendQuery( 'action=history' );
  84                 $wgOut->addScriptFile( 'history.js' );
  85
  86                 $logPage = SpecialPage::getTitleFor( 'Log' );
  87                 $logLink = $this->skin->link(
  88                         $logPage,
  89                         wfMsgHtml( 'viewpagelogs' ),
  90                         array(),
  91                         array( 'page' => $this->title->getPrefixedText() ),
  92                         array( 'known', 'noclasses' )
  93                 );
  94                 $wgOut->setSubtitle( $logLink );
  95
  96                 $feedType = $wgRequest->getVal( 'feed' );
  97                 if( $feedType ) {
  98                         wfProfileOut( __METHOD__ );
  99                         return $this->feed( $feedType );
 100                 }
 101
 102                 /*
 103                  * Fail if article doesn't exist.
 104                  */
 105                 if( !$this->title->exists() ) {
 106                         $wgOut->addWikiMsg( 'nohistory' );
 107                         # show deletion/move log if there is an entry
 108                         LogEventsList::showLogExtract(
 109                                 $wgOut,
 110                                 array( 'delete', 'move' ),
 111                                 $this->title->getPrefixedText(),
 112                                 '',
 113                                 array(  'lim' => 10,
 114                                         'conds' => array( "log_action != 'revision'" ),
 115                                         'showIfEmpty' => false,
 116                                         'msgKey' => array( 'moveddeleted-notice' )
 117                                 )
 118                         );
 119                         wfProfileOut( __METHOD__ );
 120                         return;
 121                 }
 122
 123                 /**
 124                  * Add date selector to quickly get to a certain time
 125                  */
 126                 $year = $wgRequest->getInt( 'year' );
 127                 $month = $wgRequest->getInt( 'month' );
 128                 $tagFilter = $wgRequest->getVal( 'tagfilter' );
 129                 $tagSelector = ChangeTags::buildTagFilterSelector( $tagFilter );
 130                 /**
 131                  * Option to show only revisions that have been (partially) hidden via RevisionDelete
 132                  */
 133                 if ( $wgRequest->getBool( 'deleted' ) ) {
 134                         $conds = array("rev_deleted != '0'");
 135                 } else {
 136                         $conds = array();
 137                 }
 138                 $checkDeleted = Xml::checkLabel( wfMsg( 'history-show-deleted' ),
 139                         'deleted', 'mw-show-deleted-only', $wgRequest->getBool( 'deleted' ) ) . "\n";
 140
 141                 $action = htmlspecialchars( $wgScript );
 142                 $wgOut->addHTML(
 143                         "<form action=\"$action\" method=\"get\" id=\"mw-history-searchform\">" .
 144                         Xml::fieldset(
 145                                 wfMsg( 'history-fieldset-title' ),
 146                                 false,
 147                                 array( 'id' => 'mw-history-search' )
 148                         ) .
 149                         Xml::hidden( 'title', $this->title->getPrefixedDBKey() ) . "\n" .
 150                         Xml::hidden( 'action', 'history' ) . "\n" .
 151                         Xml::dateMenu( $year, $month ) . '&#160;' .
 152                         ( $tagSelector ? ( implode( '&#160;', $tagSelector ) . '&#160;' ) : '' ) .
 153                         $checkDeleted .
 154                         Xml::submitButton( wfMsg( 'allpagessubmit' ) ) . "\n" .
 155                         '</fieldset></form>'
 156                 );
 157
 158                 wfRunHooks( 'PageHistoryBeforeList', array( &$this->article ) );
 159
 160                 /**
 161                  * Do the list
 162                  */
 163                 $pager = new HistoryPager( $this, $year, $month, $tagFilter, $conds );
 164                 $wgOut->addHTML(
 165                         $pager->getNavigationBar() .
 166                         $pager->getBody() .
 167                         $pager->getNavigationBar()
 168                 );
 169
 170                 wfProfileOut( __METHOD__ );
 171         }
 172
 173         /**
 174          * Fetch an array of revisions, specified by a given limit, offset and
 175          * direction. This is now only used by the feeds. It was previously
 176          * used by the main UI but that's now handled by the pager.
 177          *
 178          * @param $limit Integer: the limit number of revisions to get
 179          * @param $offset Integer
 180          * @param $direction Integer: either HistoryPage::DIR_PREV or HistoryPage::DIR_NEXT
 181          * @return ResultWrapper
 182          */
 183         function fetchRevisions( $limit, $offset, $direction ) {
 184                 $dbr = wfGetDB( DB_SLAVE );
 185
 186                 if( $direction == HistoryPage::DIR_PREV )
 187                         list($dirs, $oper) = array("ASC", ">=");
 188                 else /* $direction == HistoryPage::DIR_NEXT */
 189                         list($dirs, $oper) = array("DESC", "<=");
 190
 191                 if( $offset )
 192                         $offsets = array("rev_timestamp $oper '$offset'");
 193                 else
 194                         $offsets = array();
 195
 196                 $page_id = $this->title->getArticleID();
 197
 198                 return $dbr->select( 'revision',
 199                         Revision::selectFields(),
 200                         array_merge(array("rev_page=$page_id"), $offsets),
 201                         __METHOD__,
 202                         array( 'ORDER BY' => "rev_timestamp $dirs",
 203                                 'USE INDEX' => 'page_timestamp', 'LIMIT' => $limit)
 204                 );
 205         }
 206
 207         /**
 208          * Output a subscription feed listing recent edits to this page.
 209          *
 210          * @param $type String: feed type
 211          */
 212         function feed( $type ) {
 213                 global $wgFeedClasses, $wgRequest, $wgFeedLimit;
 214                 if( !FeedUtils::checkFeedOutput($type) ) {
 215                         return;
 216                 }
 217
 218                 $feed = new $wgFeedClasses[$type](
 219                         $this->title->getPrefixedText() . ' - ' .
 220                         wfMsgForContent( 'history-feed-title' ),
 221                         wfMsgForContent( 'history-feed-description' ),
 222                         $this->title->getFullUrl( 'action=history' )
 223                 );
 224
 225                 // Get a limit on number of feed entries. Provide a sane default
 226                 // of 10 if none is defined (but limit to $wgFeedLimit max)
 227                 $limit = $wgRequest->getInt( 'limit', 10 );
 228                 if( $limit > $wgFeedLimit || $limit < 1 ) {
 229                         $limit = 10;
 230                 }
 231                 $items = $this->fetchRevisions($limit, 0, HistoryPage::DIR_NEXT);
 232
 233                 $feed->outHeader();
 234                 if( $items ) {
 235                         foreach( $items as $row ) {
 236                                 $feed->outItem( $this->feedItem( $row ) );
 237                         }
 238                 } else {
 239                         $feed->outItem( $this->feedEmpty() );
 240                 }
 241                 $feed->outFooter();
 242         }
 243
 244         function feedEmpty() {
 245                 global $wgOut;
 246                 return new FeedItem(
 247                         wfMsgForContent( 'nohistory' ),
 248                         $wgOut->parse( wfMsgForContent( 'history-feed-empty' ) ),
 249                         $this->title->getFullUrl(),
 250                         wfTimestamp( TS_MW ),
 251                         '',
 252                         $this->title->getTalkPage()->getFullUrl()
 253                 );
 254         }
 255
 256         /**
 257          * Generate a FeedItem object from a given revision table row
 258          * Borrows Recent Changes' feed generation functions for formatting;
 259          * includes a diff to the previous revision (if any).
 260          *
 261          * @param $row Object: database row
 262          * @return FeedItem
 263          */
 264         function feedItem( $row ) {
 265                 $rev = new Revision( $row );
 266                 $rev->setTitle( $this->title );
 267                 $text = FeedUtils::formatDiffRow(
 268                         $this->title,
 269                         $this->title->getPreviousRevisionID( $rev->getId() ),
 270                         $rev->getId(),
 271                         $rev->getTimestamp(),
 272                         $rev->getComment()
 273                 );
 274                 if( $rev->getComment() == '' ) {
 275                         global $wgContLang;
 276                         $title = wfMsgForContent( 'history-feed-item-nocomment',
 277                                 $rev->getUserText(),
 278                                 $wgContLang->timeanddate( $rev->getTimestamp() ),
 279                                 $wgContLang->date( $rev->getTimestamp() ),
 280                                 $wgContLang->time( $rev->getTimestamp() )
 281                         );
 282                 } else {
 283                         $title = $rev->getUserText() .
 284                         wfMsgForContent( 'colon-separator' ) .
 285                         FeedItem::stripComment( $rev->getComment() );
 286                 }
 287                 return new FeedItem(
 288                         $title,
 289                         $text,
 290                         $this->title->getFullUrl( 'diff=' . $rev->getId() . '&oldid=prev' ),
 291                         $rev->getTimestamp(),
 292                         $rev->getUserText(),
 293                         $this->title->getTalkPage()->getFullUrl()
 294                 );
 295         }
 296 }
 297
 298 /**
 299  * @ingroup Pager
 300  */
 301 class HistoryPager extends ReverseChronologicalPager {
 302         public $lastRow = false, $counter, $historyPage, $title, $buttons, $conds;
 303         protected $oldIdChecked;
 304
 305         function __construct( $historyPage, $year='', $month='', $tagFilter = '', $conds = array() ) {
 306                 parent::__construct();
 307                 $this->historyPage = $historyPage;
 308                 $this->title = $this->historyPage->title;
 309                 $this->tagFilter = $tagFilter;
 310                 $this->getDateCond( $year, $month );
 311                 $this->conds = $conds;
 312         }
 313
 314         // For hook compatibility...
 315         function getArticle() {
 316                 return $this->historyPage->getArticle();
 317         }
 318
 319         function getSqlComment() {
 320                 if ( $this->conds ) {
 321                         return 'history page filtered'; // potentially slow, see CR r58153
 322                 } else {
 323                         return 'history page unfiltered';
 324                 }
 325         }
 326
 327         function getQueryInfo() {
 328                 $queryInfo = array(
 329                         'tables'  => array('revision'),
 330                         'fields'  => Revision::selectFields(),
 331                         'conds'   => array_merge(
 332                                 array( 'rev_page' => $this->historyPage->title->getArticleID() ),
 333                                 $this->conds ),
 334                         'options' => array( 'USE INDEX' => array('revision' => 'page_timestamp') ),
 335                         'join_conds' => array( 'tag_summary' => array( 'LEFT JOIN', 'ts_rev_id=rev_id' ) ),
 336                 );
 337                 ChangeTags::modifyDisplayQuery(
 338                         $queryInfo['tables'],
 339                         $queryInfo['fields'],
 340                         $queryInfo['conds'],
 341                         $queryInfo['join_conds'],
 342                         $queryInfo['options'],
 343                         $this->tagFilter
 344                 );
 345                 wfRunHooks( 'PageHistoryPager::getQueryInfo', array( &$this, &$queryInfo ) );
 346                 return $queryInfo;
 347         }
 348
 349         function getIndexField() {
 350                 return 'rev_timestamp';
 351         }
 352
 353         function formatRow( $row ) {
 354                 if( $this->lastRow ) {
 355                         $latest = ($this->counter == 1 && $this->mIsFirst);
 356                         $firstInList = $this->counter == 1;
 357                         $s = $this->historyLine( $this->lastRow, $row, $this->counter++,
 358                                 $this->title->getNotificationTimestamp(), $latest, $firstInList );
 359                 } else {
 360                         $s = '';
 361                 }
 362                 $this->lastRow = $row;
 363                 return $s;
 364         }
 365
 366         /**
 367          * Creates begin of history list with a submit button
 368          *
 369          * @return string HTML output
 370          */
 371         function getStartBody() {
 372                 global $wgScript, $wgUser, $wgOut, $wgContLang;
 373                 $this->lastRow = false;
 374                 $this->counter = 1;
 375                 $this->oldIdChecked = 0;
 376
 377                 $wgOut->wrapWikiMsg( "<div class='mw-history-legend'>\n$1\n</div>", 'histlegend' );
 378                 $s = Xml::openElement( 'form', array( 'action' => $wgScript,
 379                         'id' => 'mw-history-compare' ) ) . "\n";
 380                 $s .= Xml::hidden( 'title', $this->title->getPrefixedDbKey() ) . "\n";
 381                 $s .= Xml::hidden( 'action', 'historysubmit' ) . "\n";
 382
 383                 $this->buttons = '<div>';
 384                 if( $wgUser->isAllowed('deleterevision') ) {
 385                         $float = $wgContLang->alignEnd();
 386                         # Note bug #20966, <button> is non-standard in IE<8
 387                         $this->buttons .= Xml::element( 'button',
 388                                 array(
 389                                         'type' => 'submit',
 390                                         'name' => 'revisiondelete',
 391                                         'value' => '1',
 392                                         'style' => "float: $float;",
 393                                         'class' => 'mw-history-revisiondelete-button',
 394                                 ),
 395                                 wfMsg( 'showhideselectedversions' )
 396                         ) . "\n";
 397                 }
 398                 $this->buttons .= $this->submitButton( wfMsg( 'compareselectedversions'),
 399                         array(
 400                                 'class'     => 'historysubmit',
 401                                 'accesskey' => wfMsg( 'accesskey-compareselectedversions' ),
 402                                 'title'     => wfMsg( 'tooltip-compareselectedversions' ),
 403                         )
 404                 ) . "\n";
 405                 $this->buttons .= '</div>';
 406                 $s .= $this->buttons . '<ul id="pagehistory">' . "\n";
 407                 return $s;
 408         }
 409
 410         function getEndBody() {
 411                 if( $this->lastRow ) {
 412                         $latest = $this->counter == 1 && $this->mIsFirst;
 413                         $firstInList = $this->counter == 1;
 414                         if( $this->mIsBackwards ) {
 415                                 # Next row is unknown, but for UI reasons, probably exists if an offset has been specified
 416                                 if( $this->mOffset == '' ) {
 417                                         $next = null;
 418                                 } else {
 419                                         $next = 'unknown';
 420                                 }
 421                         } else {
 422                                 # The next row is the past-the-end row
 423                                 $next = $this->mPastTheEndRow;
 424                         }
 425                         $s = $this->historyLine( $this->lastRow, $next, $this->counter++,
 426                                 $this->title->getNotificationTimestamp(), $latest, $firstInList );
 427                 } else {
 428                         $s = '';
 429                 }
 430                 $s .= "</ul>\n";
 431                 # Add second buttons only if there is more than one rev
 432                 if( $this->getNumRows() > 2 ) {
 433                         $s .= $this->buttons;
 434                 }
 435                 $s .= '</form>';
 436                 return $s;
 437         }
 438
 439         /**
 440          * Creates a submit button
 441          *
 442          * @param $message String: text of the submit button, will be escaped
 443          * @param $attributes Array: attributes
 444          * @return String: HTML output for the submit button
 445          */
 446         function submitButton( $message, $attributes = array() ) {
 447                 # Disable submit button if history has 1 revision only
 448                 if( $this->getNumRows() > 1 ) {
 449                         return Xml::submitButton( $message , $attributes );
 450                 } else {
 451                         return '';
 452                 }
 453         }
 454
 455         /**
 456          * Returns a row from the history printout.
 457          *
 458          * @todo document some more, and maybe clean up the code (some params redundant?)
 459          *
 460          * @param $row Object: the database row corresponding to the previous line.
 461          * @param $next Mixed: the database row corresponding to the next line.
 462          * @param $counter Integer: apparently a counter of what row number we're at, counted from the top row = 1.
 463          * @param $notificationtimestamp
 464          * @param $latest Boolean: whether this row corresponds to the page's latest revision.
 465          * @param $firstInList Boolean: whether this row corresponds to the first displayed on this history page.
 466          * @return String: HTML output for the row
 467          */
 468         function historyLine( $row, $next, $counter = '', $notificationtimestamp = false,
 469                 $latest = false, $firstInList = false )
 470         {
 471                 global $wgUser, $wgLang;
 472                 $rev = new Revision( $row );
 473                 $rev->setTitle( $this->title );
 474
 475                 $curlink = $this->curLink( $rev, $latest );
 476                 $lastlink = $this->lastLink( $rev, $next, $counter );
 477                 $diffButtons = $this->diffButtons( $rev, $firstInList, $counter );
 478                 $histLinks = Html::rawElement(
 479                                 'span',
 480                                 array( 'class' => 'mw-history-histlinks' ),
 481                                 '(' . $curlink . $this->historyPage->message['pipe-separator'] . $lastlink . ') '
 482                 );
 483                 $s = $histLinks . $diffButtons;
 484
 485                 $link = $this->revLink( $rev );
 486                 $classes = array();
 487
 488                 $del = '';
 489                 // User can delete revisions...
 490                 if( $wgUser->isAllowed( 'deleterevision' ) ) {
 491                         // If revision was hidden from sysops, disable the checkbox
 492                         if( !$rev->userCan( Revision::DELETED_RESTRICTED ) ) {
 493                                 $del = Xml::check( 'deleterevisions', false, array( 'disabled' => 'disabled' ) );
 494                         // Otherwise, enable the checkbox...
 495                         } else {
 496                                 $del = Xml::check( 'showhiderevisions', false,
 497                                         array( 'name' => 'ids['.$rev->getId().']' ) );
 498                         }
 499                 // User can only view deleted revisions...
 500                 } else if( $rev->getVisibility() && $wgUser->isAllowed( 'deletedhistory' ) ) {
 501                         // If revision was hidden from sysops, disable the link
 502                         if( !$rev->userCan( Revision::DELETED_RESTRICTED ) ) {
 503                                 $cdel = $this->getSkin()->revDeleteLinkDisabled( false );
 504                         // Otherwise, show the link...
 505                         } else {
 506                                 $query = array( 'type' => 'revision',
 507                                         'target' => $this->title->getPrefixedDbkey(), 'ids' => $rev->getId() );
 508                                 $del .= $this->getSkin()->revDeleteLink( $query,
 509                                         $rev->isDeleted( Revision::DELETED_RESTRICTED ), false );
 510                         }
 511                 }
 512                 if( $del ) $s .= " $del ";
 513
 514                 $s .= " $link";
 515                 $s .= " <span class='history-user'>" .
 516                         $this->getSkin()->revUserTools( $rev, true ) . "</span>";
 517
 518                 if( $rev->isMinor() ) {
 519                         $s .= ' ' . ChangesList::flag( 'minor' );
 520                 }
 521
 522                 if( !is_null( $size = $rev->getSize() ) && !$rev->isDeleted( Revision::DELETED_TEXT ) ) {
 523                         $s .= ' ' . $this->getSkin()->formatRevisionSize( $size );
 524                 }
 525
 526                 $s .= $this->getSkin()->revComment( $rev, false, true );
 527
 528                 if( $notificationtimestamp && ($row->rev_timestamp >= $notificationtimestamp) ) {
 529                         $s .= ' <span class="updatedmarker">' .  wfMsgHtml( 'updatedmarker' ) . '</span>';
 530                 }
 531
 532                 $tools = array();
 533
 534                 # Rollback and undo links
 535                 if( !is_null( $next ) && is_object( $next ) ) {
 536                         if( $latest && $this->title->userCan( 'rollback' ) && $this->title->userCan( 'edit' ) ) {
 537                                 $tools[] = '<span class="mw-rollback-link">'.
 538                                         $this->getSkin()->buildRollbackLink( $rev ).'</span>';
 539                         }
 540
 541                         if( $this->title->quickUserCan( 'edit' )
 542                                 && !$rev->isDeleted( Revision::DELETED_TEXT )
 543                                 && !$next->rev_deleted & Revision::DELETED_TEXT )
 544                         {
 545                                 # Create undo tooltip for the first (=latest) line only
 546                                 $undoTooltip = $latest
 547                                         ? array( 'title' => wfMsg( 'tooltip-undo' ) )
 548                                         : array();
 549                                 $undolink = $this->getSkin()->link(
 550                                         $this->title,
 551                                         wfMsgHtml( 'editundo' ),
 552                                         $undoTooltip,
 553                                         array(
 554                                                 'action' => 'edit',
 555                                                 'undoafter' => $next->rev_id,
 556                                                 'undo' => $rev->getId()
 557                                         ),
 558                                         array( 'known', 'noclasses' )
 559                                 );
 560                                 $tools[] = "<span class=\"mw-history-undo\">{$undolink}</span>";
 561                         }
 562                 }
 563
 564                 if( $tools ) {
 565                         $s .= ' (' . $wgLang->pipeList( $tools ) . ')';
 566                 }
 567
 568                 # Tags
 569                 list($tagSummary, $newClasses) = ChangeTags::formatSummaryRow( $row->ts_tags, 'history' );
 570                 $classes = array_merge( $classes, $newClasses );
 571                 $s .= " $tagSummary";
 572
 573                 wfRunHooks( 'PageHistoryLineEnding', array( $this, &$row , &$s, &$classes ) );
 574
 575                 $attribs = array();
 576                 if ( $classes ) {
 577                         $attribs['class'] = implode( ' ', $classes );
 578                 }
 579
 580                 return Xml::tags( 'li', $attribs, $s ) . "\n";
 581         }
 582
 583         /**
 584          * Create a link to view this revision of the page
 585          *
 586          * @param $rev Revision
 587          * @return String
 588          */
 589         function revLink( $rev ) {
 590                 global $wgLang;
 591                 $date = $wgLang->timeanddate( wfTimestamp(TS_MW, $rev->getTimestamp()), true );
 592                 $date = htmlspecialchars( $date );
 593                 if ( $rev->userCan( Revision::DELETED_TEXT ) ) {
 594                         $link = $this->getSkin()->link(
 595                                 $this->title,
 596                                 $date,
 597                                 array(),
 598                                 array( 'oldid' => $rev->getId() ),
 599                                 array( 'known', 'noclasses' )
 600                         );
 601                 } else {
 602                         $link = $date;
 603                 }
 604                 if ( $rev->isDeleted( Revision::DELETED_TEXT ) ) {
 605                         $link = "<span class=\"history-deleted\">$link</span>";
 606                 }
 607                 return $link;
 608         }
 609
 610         /**
 611          * Create a diff-to-current link for this revision for this page
 612          *
 613          * @param $rev Revision
 614          * @param $latest Boolean: this is the latest revision of the page?
 615          * @return String
 616          */
 617         function curLink( $rev, $latest ) {
 618                 $cur = $this->historyPage->message['cur'];
 619                 if( $latest || !$rev->userCan( Revision::DELETED_TEXT ) ) {
 620                         return $cur;
 621                 } else {
 622                         return $this->getSkin()->link(
 623                                 $this->title,
 624                                 $cur,
 625                                 array(),
 626                                 array(
 627                                         'diff' => $this->title->getLatestRevID(),
 628                                         'oldid' => $rev->getId()
 629                                 ),
 630                                 array( 'known', 'noclasses' )
 631                         );
 632                 }
 633         }
 634
 635         /**
 636          * Create a diff-to-previous link for this revision for this page.
 637          *
 638          * @param $prevRev Revision: the previous revision
 639          * @param $next Mixed: the newer revision
 640          * @param $counter Integer: what row on the history list this is
 641          * @return String
 642          */
 643         function lastLink( $prevRev, $next, $counter ) {
 644                 $last = $this->historyPage->message['last'];
 645                 # $next may either be a Row, null, or "unkown"
 646                 $nextRev = is_object($next) ? new Revision( $next ) : $next;
 647                 if( is_null($next) ) {
 648                         # Probably no next row
 649                         return $last;
 650                 } elseif( $next === 'unknown' ) {
 651                         # Next row probably exists but is unknown, use an oldid=prev link
 652                         return $this->getSkin()->link(
 653                                 $this->title,
 654                                 $last,
 655                                 array(),
 656                                 array(
 657                                         'diff' => $prevRev->getId(),
 658                                         'oldid' => 'prev'
 659                                 ),
 660                                 array( 'known', 'noclasses' )
 661                         );
 662                 } elseif( !$prevRev->userCan(Revision::DELETED_TEXT)
 663                         || !$nextRev->userCan(Revision::DELETED_TEXT) )
 664                 {
 665                         return $last;
 666                 } else {
 667                         return $this->getSkin()->link(
 668                                 $this->title,
 669                                 $last,
 670                                 array(),
 671                                 array(
 672                                         'diff' => $prevRev->getId(),
 673                                         'oldid' => $next->rev_id
 674                                 ),
 675                                 array( 'known', 'noclasses' )
 676                         );
 677                 }
 678         }
 679
 680         /**
 681          * Create radio buttons for page history
 682          *
 683          * @param $rev Revision object
 684          * @param $firstInList Boolean: is this version the first one?
 685          * @param $counter Integer: a counter of what row number we're at, counted from the top row = 1.
 686          * @return String: HTML output for the radio buttons
 687          */
 688         function diffButtons( $rev, $firstInList, $counter ) {
 689                 if( $this->getNumRows() > 1 ) {
 690                         $id = $rev->getId();
 691                         $radio = array( 'type'  => 'radio', 'value' => $id );
 692                         /** @todo: move title texts to javascript */
 693                         if( $firstInList ) {
 694                                 $first = Xml::element( 'input',
 695                                         array_merge( $radio, array(
 696                                                 'style' => 'visibility:hidden',
 697                                                 'name'  => 'oldid',
 698                                                 'id' => 'mw-oldid-null' ) )
 699                                 );
 700                                 $checkmark = array( 'checked' => 'checked' );
 701                         } else {
 702                                 # Check visibility of old revisions
 703                                 if( !$rev->userCan( Revision::DELETED_TEXT ) ) {
 704                                         $radio['disabled'] = 'disabled';
 705                                         $checkmark = array(); // We will check the next possible one
 706                                 } else if( !$this->oldIdChecked ) {
 707                                         $checkmark = array( 'checked' => 'checked' );
 708                                         $this->oldIdChecked = $id;
 709                                 } else {
 710                                         $checkmark = array();
 711                                 }
 712                                 $first = Xml::element( 'input',
 713                                         array_merge( $radio, $checkmark, array(
 714                                                 'name'  => 'oldid',
 715                                                 'id' => "mw-oldid-$id" ) ) );
 716                                 $checkmark = array();
 717                         }
 718                         $second = Xml::element( 'input',
 719                                 array_merge( $radio, $checkmark, array(
 720                                         'name'  => 'diff',
 721                                         'id' => "mw-diff-$id" ) ) );
 722                         return $first . $second;
 723                 } else {
 724                         return '';
 725                 }
 726         }
 727 }
 728
 729 /**
 730  * Backwards-compatibility aliases
 731  */
 732 class PageHistory extends HistoryPage {}
 733 class PageHistoryPager extends HistoryPager {}