includes/PageHistory.php

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