includes/QueryPage.php

   1 <?php
   2 /**
   3  * Contain a class for special pages
   4  * @file
   5  * @ingroup SpecialPages
   6  */
   7
   8 /**
   9  * List of query page classes and their associated special pages,
  10  * for periodic updates.
  11  *
  12  * DO NOT CHANGE THIS LIST without testing that
  13  * maintenance/updateSpecialPages.php still works.
  14  */
  15 global $wgQueryPages; // not redundant
  16 $wgQueryPages = array(
  17 //         QueryPage subclass           Special page name         Limit (false for none, none for the default)
  18 // ----------------------------------------------------------------------------
  19         array( 'AncientPagesPage',              'Ancientpages'                  ),
  20         array( 'BrokenRedirectsPage',           'BrokenRedirects'               ),
  21         array( 'DeadendPagesPage',              'Deadendpages'                  ),
  22         array( 'DisambiguationsPage',           'Disambiguations'               ),
  23         array( 'DoubleRedirectsPage',           'DoubleRedirects'               ),
  24         array( 'FileDuplicateSearchPage',       'FileDuplicateSearch'           ),
  25         array( 'LinkSearchPage',                'LinkSearch'                    ),
  26         array( 'ListredirectsPage',             'Listredirects'                 ),
  27         array( 'LonelyPagesPage',               'Lonelypages'                   ),
  28         array( 'LongPagesPage',                 'Longpages'                     ),
  29         array( 'MIMEsearchPage',                'MIMEsearch'                    ),
  30         array( 'MostcategoriesPage',            'Mostcategories'                ),
  31         array( 'MostimagesPage',                'Mostimages'                    ),
  32         array( 'MostlinkedCategoriesPage',      'Mostlinkedcategories'          ),
  33         array( 'MostlinkedtemplatesPage',       'Mostlinkedtemplates'           ),
  34         array( 'MostlinkedPage',                'Mostlinked'                    ),
  35         array( 'MostrevisionsPage',             'Mostrevisions'                 ),
  36         array( 'FewestrevisionsPage',           'Fewestrevisions'               ),
  37         array( 'ShortPagesPage',                'Shortpages'                    ),
  38         array( 'UncategorizedCategoriesPage',   'Uncategorizedcategories'       ),
  39         array( 'UncategorizedPagesPage',        'Uncategorizedpages'            ),
  40         array( 'UncategorizedImagesPage',       'Uncategorizedimages'           ),
  41         array( 'UncategorizedTemplatesPage',    'Uncategorizedtemplates'        ),
  42         array( 'UnusedCategoriesPage',          'Unusedcategories'              ),
  43         array( 'UnusedimagesPage',              'Unusedimages'                  ),
  44         array( 'WantedCategoriesPage',          'Wantedcategories'              ),
  45         array( 'WantedFilesPage',               'Wantedfiles'                   ),
  46         array( 'WantedPagesPage',               'Wantedpages'                   ),
  47         array( 'WantedTemplatesPage',           'Wantedtemplates'               ),
  48         array( 'UnwatchedPagesPage',            'Unwatchedpages'                ),
  49         array( 'UnusedtemplatesPage',           'Unusedtemplates'               ),
  50         array( 'WithoutInterwikiPage',          'Withoutinterwiki'              ),
  51 );
  52 wfRunHooks( 'wgQueryPages', array( &$wgQueryPages ) );
  53
  54 global $wgDisableCounters;
  55 if ( !$wgDisableCounters )
  56         $wgQueryPages[] = array( 'PopularPagesPage', 'Popularpages' );
  57
  58
  59 /**
  60  * This is a class for doing query pages; since they're almost all the same,
  61  * we factor out some of the functionality into a superclass, and let
  62  * subclasses derive from it.
  63  * @ingroup SpecialPage
  64  */
  65 abstract class QueryPage extends SpecialPage {
  66         /**
  67          * Whether or not we want plain listoutput rather than an ordered list
  68          *
  69          * @var bool
  70          */
  71         var $listoutput = false;
  72
  73         /**
  74          * The offset and limit in use, as passed to the query() function
  75          *
  76          * @var integer
  77          */
  78         var $offset = 0;
  79         var $limit = 0;
  80
  81         /**
  82          * The number of rows returned by the query. Reading this variable
  83          * only makes sense in functions that are run after the query has been
  84          * done, such as preprocessResults() and formatRow().
  85          */
  86         protected $numRows;
  87
  88         /**
  89          * Wheter to show prev/next links
  90          */
  91         protected $shownavigation = true;
  92
  93         /**
  94          * A mutator for $this->listoutput;
  95          *
  96          * @param $bool Boolean
  97          */
  98         function setListoutput( $bool ) {
  99                 $this->listoutput = $bool;
 100         }
 101
 102         /**
 103          * Subclasses return an SQL query here, formatted as an array with the
 104          * following keys:
 105          *    tables => Table(s) for passing to Database::select()
 106          *    fields => Field(s) for passing to Database::select(), may be *
 107          *    conds => WHERE conditions
 108          *    options => options
 109          *    join_conds => JOIN conditions
 110          *
 111          * Note that the query itself should return the following three columns:
 112          * 'namespace', 'title', and 'value'. 'value' is used for sorting.
 113          *
 114          * These may be stored in the querycache table for expensive queries,
 115          * and that cached data will be returned sometimes, so the presence of
 116          * extra fields can't be relied upon. The cached 'value' column will be
 117          * an integer; non-numeric values are useful only for sorting the
 118          * initial query (except if they're timestamps, see usesTimestamps()).
 119          *
 120          * Don't include an ORDER or LIMIT clause, they will be added.
 121          *
 122          * If this function is not overridden or returns something other than
 123          * an array, getSQL() will be used instead. This is for backwards
 124          * compatibility only and is strongly deprecated.
 125          * @return array
 126          * @since 1.18
 127          */
 128         function getQueryInfo() {
 129                 return null;
 130         }
 131
 132         /**
 133          * For back-compat, subclasses may return a raw SQL query here, as a string.
 134          * This is stronly deprecated; getQueryInfo() should be overridden instead.
 135          * @return string
 136          * @deprecated since 1.18
 137          */
 138         function getSQL() {
 139                 throw new MWException( "Bug in a QueryPage: doesn't implement getQueryInfo() nor getQuery() properly" );
 140         }
 141
 142         /**
 143          * Subclasses return an array of fields to order by here. Don't append
 144          * DESC to the field names, that'll be done automatically if
 145          * sortDescending() returns true.
 146          * @return array
 147          * @since 1.18
 148          */
 149         function getOrderFields() {
 150                 return array( 'value' );
 151         }
 152
 153         /**
 154          * Does this query return timestamps rather than integers in its
 155          * 'value' field? If true, this class will convert 'value' to a
 156          * UNIX timestamp for caching.
 157          * NOTE: formatRow() may get timestamps in TS_MW (mysql), TS_DB (pgsql)
 158          *       or TS_UNIX (querycache) format, so be sure to always run them
 159          *       through wfTimestamp()
 160          * @return bool
 161          * @since 1.18
 162          */
 163         function usesTimestamps() {
 164                 return false;
 165         }
 166
 167         /**
 168          * Override to sort by increasing values
 169          *
 170          * @return Boolean
 171          */
 172         function sortDescending() {
 173                 return true;
 174         }
 175
 176         /**
 177          * Is this query expensive (for some definition of expensive)? Then we
 178          * don't let it run in miser mode. $wgDisableQueryPages causes all query
 179          * pages to be declared expensive. Some query pages are always expensive.
 180          *
 181          * @return Boolean
 182          */
 183         function isExpensive() {
 184                 global $wgDisableQueryPages;
 185                 return $wgDisableQueryPages;
 186         }
 187
 188         /**
 189          * Is the output of this query cacheable? Non-cacheable expensive pages
 190          * will be disabled in miser mode and will not have their results written
 191          * to the querycache table.
 192          * @return Boolean
 193          * @since 1.18
 194          */
 195         public function isCacheable() {
 196                 return true;
 197         }
 198
 199         /**
 200          * Whether or not the output of the page in question is retrieved from
 201          * the database cache.
 202          *
 203          * @return Boolean
 204          */
 205         function isCached() {
 206                 global $wgMiserMode;
 207
 208                 return $this->isExpensive() && $wgMiserMode;
 209         }
 210
 211         /**
 212          * Sometime we dont want to build rss / atom feeds.
 213          *
 214          * @return Boolean
 215          */
 216         function isSyndicated() {
 217                 return true;
 218         }
 219
 220         /**
 221          * Formats the results of the query for display. The skin is the current
 222          * skin; you can use it for making links. The result is a single row of
 223          * result data. You should be able to grab SQL results off of it.
 224          * If the function returns false, the line output will be skipped.
 225          * @param $skin Skin
 226          * @param $result object Result row
 227          * @return mixed String or false to skip
 228          *
 229          * @param $skin Skin object
 230          * @param $result Object: database row
 231          */
 232         abstract function formatResult( $skin, $result );
 233
 234         /**
 235          * The content returned by this function will be output before any result
 236          *
 237          * @return String
 238          */
 239         function getPageHeader() {
 240                 return '';
 241         }
 242
 243         /**
 244          * If using extra form wheely-dealies, return a set of parameters here
 245          * as an associative array. They will be encoded and added to the paging
 246          * links (prev/next/lengths).
 247          *
 248          * @return Array
 249          */
 250         function linkParameters() {
 251                 return array();
 252         }
 253
 254         /**
 255          * Some special pages (for example SpecialListusers) might not return the
 256          * current object formatted, but return the previous one instead.
 257          * Setting this to return true will ensure formatResult() is called
 258          * one more time to make sure that the very last result is formatted
 259          * as well.
 260          */
 261         function tryLastResult() {
 262                 return false;
 263         }
 264
 265         /**
 266          * Clear the cache and save new results
 267          *
 268          * @param $limit Integer: limit for SQL statement
 269          * @param $ignoreErrors Boolean: whether to ignore database errors
 270          */
 271         function recache( $limit, $ignoreErrors = true ) {
 272                 if ( !$this->isCacheable() ) {
 273                         return 0;
 274                 }
 275
 276                 $fname = get_class( $this ) . '::recache';
 277                 $dbw = wfGetDB( DB_MASTER );
 278                 $dbr = wfGetDB( DB_SLAVE, array( $this->getName(), __METHOD__, 'vslow' ) );
 279                 if ( !$dbw || !$dbr ) {
 280                         return false;
 281                 }
 282
 283                 if ( $ignoreErrors ) {
 284                         $ignoreW = $dbw->ignoreErrors( true );
 285                         $ignoreR = $dbr->ignoreErrors( true );
 286                 }
 287
 288                 # Clear out any old cached data
 289                 $dbw->delete( 'querycache', array( 'qc_type' => $this->getName() ), $fname );
 290                 # Do query
 291                 $res = $this->reallyDoQuery( $limit, false );
 292                 $num = false;
 293                 if ( $res ) {
 294                         $num = $dbr->numRows( $res );
 295                         # Fetch results
 296                         $vals = array();
 297                         while ( $res && $row = $dbr->fetchObject( $res ) ) {
 298                                 if ( isset( $row->value ) ) {
 299                                         if ( $this->usesTimestamps() ) {
 300                                                 $value = wfTimestamp( TS_UNIX,
 301                                                         $row->value );
 302                                         } else {
 303                                                 $value = intval( $row->value ); // @bug 14414
 304                                         }
 305                                 } else {
 306                                         $value = 0;
 307                                 }
 308
 309                                 $vals[] = array( 'qc_type' => $this->getName(),
 310                                                 'qc_namespace' => $row->namespace,
 311                                                 'qc_title' => $row->title,
 312                                                 'qc_value' => $value );
 313                         }
 314
 315                         # Save results into the querycache table on the master
 316                         if ( count( $vals ) ) {
 317                                 if ( !$dbw->insert( 'querycache', $vals, __METHOD__ ) ) {
 318                                         // Set result to false to indicate error
 319                                         $num = false;
 320                                 }
 321                         }
 322                         if ( $ignoreErrors ) {
 323                                 $dbw->ignoreErrors( $ignoreW );
 324                                 $dbr->ignoreErrors( $ignoreR );
 325                         }
 326
 327                         # Update the querycache_info record for the page
 328                         $dbw->delete( 'querycache_info', array( 'qci_type' => $this->getName() ), $fname );
 329                         $dbw->insert( 'querycache_info', array( 'qci_type' => $this->getName(), 'qci_timestamp' => $dbw->timestamp() ), $fname );
 330
 331                 }
 332                 return $num;
 333         }
 334
 335         /**
 336          * Run the query and return the result
 337          * @param $limit mixed Numerical limit or false for no limit
 338          * @param $offset mixed Numerical offset or false for no offset
 339          * @return ResultWrapper
 340          * @since 1.18
 341          */
 342         function reallyDoQuery( $limit, $offset = false ) {
 343                 $fname = get_class( $this ) . "::reallyDoQuery";
 344                 $dbr = wfGetDB( DB_SLAVE );
 345                 $query = $this->getQueryInfo();
 346                 $order = $this->getOrderFields();
 347                 if ( $this->sortDescending() ) {
 348                         foreach ( $order as &$field ) {
 349                                 $field .= ' DESC';
 350                         }
 351                 }
 352                 if ( is_array( $query ) ) {
 353                         $tables = isset( $query['tables'] ) ? (array)$query['tables'] : array();
 354                         $fields = isset( $query['fields'] ) ? (array)$query['fields'] : array();
 355                         $conds = isset( $query['conds'] ) ? (array)$query['conds'] : array();
 356                         $options = isset( $query['options'] ) ? (array)$query['options'] : array();
 357                         $join_conds = isset( $query['join_conds'] ) ? (array)$query['join_conds'] : array();
 358                         if ( count( $order ) ) {
 359                                 $options['ORDER BY'] = implode( ', ', $order );
 360                         }
 361                         if ( $limit !== false ) {
 362                                 $options['LIMIT'] = intval( $limit );
 363                         }
 364                         if ( $offset !== false ) {
 365                                 $options['OFFSET'] = intval( $offset );
 366                         }
 367
 368                         $res = $dbr->select( $tables, $fields, $conds, $fname,
 369                                         $options, $join_conds
 370                         );
 371                 } else {
 372                         // Old-fashioned raw SQL style, deprecated
 373                         $sql = $this->getSQL();
 374                         $sql .= ' ORDER BY ' . implode( ', ', $order );
 375                         $sql = $dbr->limitResult( $sql, $limit, $offset );
 376                         $res = $dbr->query( $sql );
 377                 }
 378                 return $dbr->resultObject( $res );
 379         }
 380
 381         /**
 382          * Parameters and order changed in 1.18
 383          */
 384         function doQuery( $limit, $offset = false ) {
 385                 if ( $this->isCached() && $this->isCacheable() ) {
 386                         return $this->fetchFromCache( $limit, $offset );
 387                 } else {
 388                         return $this->reallyDoQuery( $limit, $offset );
 389                 }
 390         }
 391
 392         /**
 393          * Fetch the query results from the query cache
 394          * @param $limit mixed Numerical limit or false for no limit
 395          * @param $offset mixed Numerical offset or false for no offset
 396          * @return ResultWrapper
 397          * @since 1.18
 398          */
 399         function fetchFromCache( $limit, $offset = false ) {
 400                 $dbr = wfGetDB( DB_SLAVE );
 401                 $options = array ();
 402                 if ( $limit !== false ) {
 403                         $options['LIMIT'] = intval( $limit );
 404                 }
 405                 if ( $offset !== false ) {
 406                         $options['OFFSET'] = intval( $offset );
 407                 }
 408                 $res = $dbr->select( 'querycache', array( 'qc_type',
 409                                 'qc_namespace AS namespace',
 410                                 'qc_title AS title',
 411                                 'qc_value AS value' ),
 412                                 array( 'qc_type' => $this->getName() ),
 413                                 __METHOD__, $options
 414                 );
 415                 return $dbr->resultObject( $res );
 416         }
 417
 418         /**
 419          * This is the actual workhorse. It does everything needed to make a
 420          * real, honest-to-gosh query page.
 421          */
 422         function execute( $par ) {
 423                 global $wgUser, $wgOut, $wgLang;
 424
 425                 if ( !$this->userCanExecute( $wgUser ) ) {
 426                         $this->displayRestrictionError();
 427                         return;
 428                 }
 429
 430                 if ( $this->limit == 0 && $this->offset == 0 )
 431                         list( $this->limit, $this->offset ) = wfCheckLimits();
 432                 $sname = $this->getName();
 433                 $fname = get_class( $this ) . '::doQuery';
 434                 $dbr = wfGetDB( DB_SLAVE );
 435
 436                 $this->setHeaders();
 437                 $wgOut->setSyndicated( $this->isSyndicated() );
 438
 439                 if ( $this->isCached() && !$this->isCacheable() ) {
 440                         $wgOut->setSyndicated( false );
 441                         $wgOut->addWikiMsg( 'querypage-disabled' );
 442                         return 0;
 443                 }
 444
 445                 // TODO: Use doQuery()
 446                 // $res = null;
 447                 if ( !$this->isCached() ) {
 448                         $res = $this->reallyDoQuery( $this->limit, $this->offset );
 449                 } else {
 450                         # Get the cached result
 451                         $res = $this->fetchFromCache( $this->limit, $this->offset );
 452                         if ( !$this->listoutput ) {
 453
 454                                 # Fetch the timestamp of this update
 455                                 $tRes = $dbr->select( 'querycache_info', array( 'qci_timestamp' ), array( 'qci_type' => $sname ), $fname );
 456                                 $tRow = $dbr->fetchObject( $tRes );
 457
 458                                 if ( $tRow ) {
 459                                         $updated = $wgLang->timeanddate( $tRow->qci_timestamp, true, true );
 460                                         $updateddate = $wgLang->date( $tRow->qci_timestamp, true, true );
 461                                         $updatedtime = $wgLang->time( $tRow->qci_timestamp, true, true );
 462                                         $wgOut->addMeta( 'Data-Cache-Time', $tRow->qci_timestamp );
 463                                         $wgOut->addInlineScript( "var dataCacheTime = '{$tRow->qci_timestamp}';" );
 464                                         $wgOut->addWikiMsg( 'perfcachedts', $updated, $updateddate, $updatedtime );
 465                                 } else {
 466                                         $wgOut->addWikiMsg( 'perfcached' );
 467                                 }
 468
 469                                 # If updates on this page have been disabled, let the user know
 470                                 # that the data set won't be refreshed for now
 471                                 global $wgDisableQueryPageUpdate;
 472                                 if ( is_array( $wgDisableQueryPageUpdate ) && in_array( $this->getName(), $wgDisableQueryPageUpdate ) ) {
 473                                         $wgOut->addWikiMsg( 'querypage-no-updates' );
 474                                 }
 475
 476                         }
 477
 478                 }
 479
 480                 $this->numRows = $dbr->numRows( $res );
 481
 482                 $this->preprocessResults( $dbr, $res );
 483
 484                 $wgOut->addHTML( Xml::openElement( 'div', array( 'class' => 'mw-spcontent' ) ) );
 485
 486                 # Top header and navigation
 487                 if ( $this->shownavigation ) {
 488                         $wgOut->addHTML( $this->getPageHeader() );
 489                         if ( $this->numRows > 0 ) {
 490                                 $wgOut->addHTML( '<p>' . wfShowingResults( $this->offset, $this->numRows ) . '</p>' );
 491                                 # Disable the "next" link when we reach the end
 492                                 $paging = wfViewPrevNext( $this->offset, $this->limit,
 493                                         $this->getTitle( $par ),
 494                                         wfArrayToCGI( $this->linkParameters() ), ( $this->numRows < $this->limit ) );
 495                                 $wgOut->addHTML( '<p>' . $paging . '</p>' );
 496                         } else {
 497                                 # No results to show, so don't bother with "showing X of Y" etc.
 498                                 # -- just let the user know and give up now
 499                                 $wgOut->addHTML( '<p>' . wfMsgHtml( 'specialpage-empty' ) . '</p>' );
 500                                 $wgOut->addHTML( Xml::closeElement( 'div' ) );
 501                                 return;
 502                         }
 503                 }
 504
 505                 # The actual results; specialist subclasses will want to handle this
 506                 # with more than a straight list, so we hand them the info, plus
 507                 # an OutputPage, and let them get on with it
 508                 $this->outputResults( $wgOut,
 509                         $wgUser->getSkin(),
 510                         $dbr, # Should use a ResultWrapper for this
 511                         $res,
 512                         $this->numRows,
 513                         $this->offset );
 514
 515                 # Repeat the paging links at the bottom
 516                 if ( $this->shownavigation ) {
 517                         $wgOut->addHTML( '<p>' . $paging . '</p>' );
 518                 }
 519
 520                 $wgOut->addHTML( Xml::closeElement( 'div' ) );
 521
 522                 return $this->numRows;
 523         }
 524
 525         /**
 526          * Format and output report results using the given information plus
 527          * OutputPage
 528          *
 529          * @param $out OutputPage to print to
 530          * @param $skin Skin: user skin to use
 531          * @param $dbr Database (read) connection to use
 532          * @param $res Integer: result pointer
 533          * @param $num Integer: number of available result rows
 534          * @param $offset Integer: paging offset
 535          */
 536         protected function outputResults( $out, $skin, $dbr, $res, $num, $offset ) {
 537                 global $wgContLang;
 538
 539                 if ( $num > 0 ) {
 540                         $html = array();
 541                         if ( !$this->listoutput )
 542                                 $html[] = $this->openList( $offset );
 543
 544                         # $res might contain the whole 1,000 rows, so we read up to
 545                         # $num [should update this to use a Pager]
 546                         for ( $i = 0; $i < $num && $row = $dbr->fetchObject( $res ); $i++ ) {
 547                                 $line = $this->formatResult( $skin, $row );
 548                                 if ( $line ) {
 549                                         $attr = ( isset( $row->usepatrol ) && $row->usepatrol && $row->patrolled == 0 )
 550                                                 ? ' class="not-patrolled"'
 551                                                 : '';
 552                                         $html[] = $this->listoutput
 553                                                 ? $line
 554                                                 : "<li{$attr}>{$line}</li>\n";
 555                                 }
 556                         }
 557
 558                         # Flush the final result
 559                         if ( $this->tryLastResult() ) {
 560                                 $row = null;
 561                                 $line = $this->formatResult( $skin, $row );
 562                                 if ( $line ) {
 563                                         $attr = ( isset( $row->usepatrol ) && $row->usepatrol && $row->patrolled == 0 )
 564                                                 ? ' class="not-patrolled"'
 565                                                 : '';
 566                                         $html[] = $this->listoutput
 567                                                 ? $line
 568                                                 : "<li{$attr}>{$line}</li>\n";
 569                                 }
 570                         }
 571
 572                         if ( !$this->listoutput )
 573                                 $html[] = $this->closeList();
 574
 575                         $html = $this->listoutput
 576                                 ? $wgContLang->listToText( $html )
 577                                 : implode( '', $html );
 578
 579                         $out->addHTML( $html );
 580                 }
 581         }
 582
 583         function openList( $offset ) {
 584                 return "\n<ol start='" . ( $offset + 1 ) . "' class='special'>\n";
 585         }
 586
 587         function closeList() {
 588                 return "</ol>\n";
 589         }
 590
 591         /**
 592          * Do any necessary preprocessing of the result object.
 593          */
 594         function preprocessResults( $db, $res ) {}
 595
 596         /**
 597          * Similar to above, but packaging in a syndicated feed instead of a web page
 598          */
 599         function doFeed( $class = '', $limit = 50 ) {
 600                 global $wgFeed, $wgFeedClasses;
 601
 602                 if ( !$wgFeed ) {
 603                         global $wgOut;
 604                         $wgOut->addWikiMsg( 'feed-unavailable' );
 605                         return;
 606                 }
 607
 608                 global $wgFeedLimit;
 609                 if ( $limit > $wgFeedLimit ) {
 610                         $limit = $wgFeedLimit;
 611                 }
 612
 613                 if ( isset( $wgFeedClasses[$class] ) ) {
 614                         $feed = new $wgFeedClasses[$class](
 615                                 $this->feedTitle(),
 616                                 $this->feedDesc(),
 617                                 $this->feedUrl() );
 618                         $feed->outHeader();
 619
 620                         $dbr = wfGetDB( DB_SLAVE );
 621                         $res = $this->reallyDoQuery( $limit, 0 );
 622                         foreach ( $res as $obj ) {
 623                                 $item = $this->feedResult( $obj );
 624                                 if ( $item ) {
 625                                         $feed->outItem( $item );
 626                                 }
 627                         }
 628
 629                         $feed->outFooter();
 630                         return true;
 631                 } else {
 632                         return false;
 633                 }
 634         }
 635
 636         /**
 637          * Override for custom handling. If the titles/links are ok, just do
 638          * feedItemDesc()
 639          */
 640         function feedResult( $row ) {
 641                 if ( !isset( $row->title ) ) {
 642                         return null;
 643                 }
 644                 $title = Title::MakeTitle( intval( $row->namespace ), $row->title );
 645                 if ( $title ) {
 646                         $date = isset( $row->timestamp ) ? $row->timestamp : '';
 647                         $comments = '';
 648                         if ( $title ) {
 649                                 $talkpage = $title->getTalkPage();
 650                                 $comments = $talkpage->getFullURL();
 651                         }
 652
 653                         return new FeedItem(
 654                                 $title->getPrefixedText(),
 655                                 $this->feedItemDesc( $row ),
 656                                 $title->getFullURL(),
 657                                 $date,
 658                                 $this->feedItemAuthor( $row ),
 659                                 $comments );
 660                 } else {
 661                         return null;
 662                 }
 663         }
 664
 665         function feedItemDesc( $row ) {
 666                 return isset( $row->comment ) ? htmlspecialchars( $row->comment ) : '';
 667         }
 668
 669         function feedItemAuthor( $row ) {
 670                 return isset( $row->user_text ) ? $row->user_text : '';
 671         }
 672
 673         function feedTitle() {
 674                 global $wgLanguageCode, $wgSitename;
 675                 $page = SpecialPage::getPage( $this->getName() );
 676                 $desc = $page->getDescription();
 677                 return "$wgSitename - $desc [$wgLanguageCode]";
 678         }
 679
 680         function feedDesc() {
 681                 return wfMsgExt( 'tagline', 'parsemag' );
 682         }
 683
 684         function feedUrl() {
 685                 $title = SpecialPage::getTitleFor( $this->getName() );
 686                 return $title->getFullURL();
 687         }
 688 }
 689
 690 /**
 691  * Class definition for a wanted query page like
 692  * WantedPages, WantedTemplates, etc
 693  */
 694 abstract class WantedQueryPage extends QueryPage {
 695
 696         function isExpensive() {
 697                 return true;
 698         }
 699
 700         function isSyndicated() {
 701                 return false;
 702         }
 703
 704         /**
 705          * Cache page existence for performance
 706          */
 707         function preprocessResults( $db, $res ) {
 708                 $batch = new LinkBatch;
 709                 foreach ( $res as $row ) {
 710                         $batch->add( $row->namespace, $row->title );
 711                 }
 712                 $batch->execute();
 713
 714                 // Back to start for display
 715                 if ( $db->numRows( $res ) > 0 )
 716                         // If there are no rows we get an error seeking.
 717                         $db->dataSeek( $res, 0 );
 718         }
 719
 720         /**
 721          * Should formatResult() always check page existence, even if
 722          * the results are fresh?  This is a (hopefully temporary)
 723          * kluge for Special:WantedFiles, which may contain false
 724          * positives for files that exist e.g. in a shared repo (bug
 725          * 6220).
 726          */
 727         function forceExistenceCheck() {
 728                 return false;
 729         }
 730
 731         /**
 732          * Format an individual result
 733          *
 734          * @param $skin Skin to use for UI elements
 735          * @param $result Result row
 736          * @return string
 737          */
 738         public function formatResult( $skin, $result ) {
 739                 $title = Title::makeTitleSafe( $result->namespace, $result->title );
 740                 if ( $title instanceof Title ) {
 741                         if ( $this->isCached() || $this->forceExistenceCheck() ) {
 742                                 $pageLink = $title->isKnown()
 743                                         ? '<del>' . $skin->link( $title ) . '</del>'
 744                                         : $skin->link(
 745                                                 $title,
 746                                                 null,
 747                                                 array(),
 748                                                 array(),
 749                                                 array( 'broken' )
 750                                         );
 751                         } else {
 752                                 $pageLink = $skin->link(
 753                                         $title,
 754                                         null,
 755                                         array(),
 756                                         array(),
 757                                         array( 'broken' )
 758                                 );
 759                         }
 760                         return wfSpecialList( $pageLink, $this->makeWlhLink( $title, $skin, $result ) );
 761                 } else {
 762                         $tsafe = htmlspecialchars( $result->title );
 763                         return wfMsgHtml( 'wantedpages-badtitle', $tsafe );
 764                 }
 765         }
 766
 767         /**
 768          * Make a "what links here" link for a given title
 769          *
 770          * @param $title Title to make the link for
 771          * @param $skin Skin object to use
 772          * @param $result Object: result row
 773          * @return string
 774          */
 775         private function makeWlhLink( $title, $skin, $result ) {
 776                 global $wgLang;
 777                 $wlh = SpecialPage::getTitleFor( 'Whatlinkshere' );
 778                 $label = wfMsgExt( 'nlinks', array( 'parsemag', 'escape' ),
 779                 $wgLang->formatNum( $result->value ) );
 780                 return $skin->link( $wlh, $label, array(), array( 'target' => $title->getPrefixedText() ) );
 781         }
 782 }