includes/QueryPage.php

   1 <?php
   2 /**
   3  * Base code for "query" special pages.
   4  *
   5  * This program is free software; you can redistribute it and/or modify
   6  * it under the terms of the GNU General Public License as published by
   7  * the Free Software Foundation; either version 2 of the License, or
   8  * (at your option) any later version.
   9  *
  10  * This program is distributed in the hope that it will be useful,
  11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  13  * GNU General Public License for more details.
  14  *
  15  * You should have received a copy of the GNU General Public License along
  16  * with this program; if not, write to the Free Software Foundation, Inc.,
  17  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
  18  * http://www.gnu.org/copyleft/gpl.html
  19  *
  20  * @file
  21  * @ingroup SpecialPage
  22  */
  23
  24 /**
  25  * List of query page classes and their associated special pages,
  26  * for periodic updates.
  27  *
  28  * DO NOT CHANGE THIS LIST without testing that
  29  * maintenance/updateSpecialPages.php still works.
  30  */
  31 global $wgQueryPages; // not redundant
  32 $wgQueryPages = array(
  33 //         QueryPage subclass           Special page name         Limit (false for none, none for the default)
  34 // ----------------------------------------------------------------------------
  35         array( 'AncientPagesPage',              'Ancientpages'                  ),
  36         array( 'BrokenRedirectsPage',           'BrokenRedirects'               ),
  37         array( 'DeadendPagesPage',              'Deadendpages'                  ),
  38         array( 'DisambiguationsPage',           'Disambiguations'               ),
  39         array( 'DoubleRedirectsPage',           'DoubleRedirects'               ),
  40         array( 'FileDuplicateSearchPage',       'FileDuplicateSearch'           ),
  41         array( 'LinkSearchPage',                'LinkSearch'                    ),
  42         array( 'ListredirectsPage',             'Listredirects'                 ),
  43         array( 'LonelyPagesPage',               'Lonelypages'                   ),
  44         array( 'LongPagesPage',                 'Longpages'                     ),
  45         array( 'MIMEsearchPage',                'MIMEsearch'                    ),
  46         array( 'MostcategoriesPage',            'Mostcategories'                ),
  47         array( 'MostimagesPage',                'Mostimages'                    ),
  48         array( 'MostlinkedCategoriesPage',      'Mostlinkedcategories'          ),
  49         array( 'MostlinkedtemplatesPage',       'Mostlinkedtemplates'           ),
  50         array( 'MostlinkedPage',                'Mostlinked'                    ),
  51         array( 'MostrevisionsPage',             'Mostrevisions'                 ),
  52         array( 'FewestrevisionsPage',           'Fewestrevisions'               ),
  53         array( 'ShortPagesPage',                'Shortpages'                    ),
  54         array( 'UncategorizedCategoriesPage',   'Uncategorizedcategories'       ),
  55         array( 'UncategorizedPagesPage',        'Uncategorizedpages'            ),
  56         array( 'UncategorizedImagesPage',       'Uncategorizedimages'           ),
  57         array( 'UncategorizedTemplatesPage',    'Uncategorizedtemplates'        ),
  58         array( 'UnusedCategoriesPage',          'Unusedcategories'              ),
  59         array( 'UnusedimagesPage',              'Unusedimages'                  ),
  60         array( 'WantedCategoriesPage',          'Wantedcategories'              ),
  61         array( 'WantedFilesPage',               'Wantedfiles'                   ),
  62         array( 'WantedPagesPage',               'Wantedpages'                   ),
  63         array( 'WantedTemplatesPage',           'Wantedtemplates'               ),
  64         array( 'UnwatchedPagesPage',            'Unwatchedpages'                ),
  65         array( 'UnusedtemplatesPage',           'Unusedtemplates'               ),
  66         array( 'WithoutInterwikiPage',          'Withoutinterwiki'              ),
  67 );
  68 wfRunHooks( 'wgQueryPages', array( &$wgQueryPages ) );
  69
  70 global $wgDisableCounters;
  71 if ( !$wgDisableCounters )
  72         $wgQueryPages[] = array( 'PopularPagesPage', 'Popularpages' );
  73
  74
  75 /**
  76  * This is a class for doing query pages; since they're almost all the same,
  77  * we factor out some of the functionality into a superclass, and let
  78  * subclasses derive from it.
  79  * @ingroup SpecialPage
  80  */
  81 abstract class QueryPage extends SpecialPage {
  82         /**
  83          * Whether or not we want plain listoutput rather than an ordered list
  84          *
  85          * @var bool
  86          */
  87         var $listoutput = false;
  88
  89         /**
  90          * The offset and limit in use, as passed to the query() function
  91          *
  92          * @var integer
  93          */
  94         var $offset = 0;
  95         var $limit = 0;
  96
  97         /**
  98          * The number of rows returned by the query. Reading this variable
  99          * only makes sense in functions that are run after the query has been
 100          * done, such as preprocessResults() and formatRow().
 101          */
 102         protected $numRows;
 103
 104         protected $cachedTimestamp = null;
 105
 106         /**
 107          * Wheter to show prev/next links
 108          */
 109         protected $shownavigation = true;
 110
 111         /**
 112          * A mutator for $this->listoutput;
 113          *
 114          * @param $bool Boolean
 115          */
 116         function setListoutput( $bool ) {
 117                 $this->listoutput = $bool;
 118         }
 119
 120         /**
 121          * Subclasses return an SQL query here, formatted as an array with the
 122          * following keys:
 123          *    tables => Table(s) for passing to Database::select()
 124          *    fields => Field(s) for passing to Database::select(), may be *
 125          *    conds => WHERE conditions
 126          *    options => options
 127          *    join_conds => JOIN conditions
 128          *
 129          * Note that the query itself should return the following three columns:
 130          * 'namespace', 'title', and 'value'. 'value' is used for sorting.
 131          *
 132          * These may be stored in the querycache table for expensive queries,
 133          * and that cached data will be returned sometimes, so the presence of
 134          * extra fields can't be relied upon. The cached 'value' column will be
 135          * an integer; non-numeric values are useful only for sorting the
 136          * initial query (except if they're timestamps, see usesTimestamps()).
 137          *
 138          * Don't include an ORDER or LIMIT clause, they will be added.
 139          *
 140          * If this function is not overridden or returns something other than
 141          * an array, getSQL() will be used instead. This is for backwards
 142          * compatibility only and is strongly deprecated.
 143          * @return array
 144          * @since 1.18
 145          */
 146         function getQueryInfo() {
 147                 return null;
 148         }
 149
 150         /**
 151          * For back-compat, subclasses may return a raw SQL query here, as a string.
 152          * This is stronly deprecated; getQueryInfo() should be overridden instead.
 153          * @return string
 154          */
 155         function getSQL() {
 156                 /* Implement getQueryInfo() instead */
 157                 throw new MWException( "Bug in a QueryPage: doesn't implement getQueryInfo() nor getQuery() properly" );
 158         }
 159
 160         /**
 161          * Subclasses return an array of fields to order by here. Don't append
 162          * DESC to the field names, that'll be done automatically if
 163          * sortDescending() returns true.
 164          * @return array
 165          * @since 1.18
 166          */
 167         function getOrderFields() {
 168                 return array( 'value' );
 169         }
 170
 171         /**
 172          * Does this query return timestamps rather than integers in its
 173          * 'value' field? If true, this class will convert 'value' to a
 174          * UNIX timestamp for caching.
 175          * NOTE: formatRow() may get timestamps in TS_MW (mysql), TS_DB (pgsql)
 176          *       or TS_UNIX (querycache) format, so be sure to always run them
 177          *       through wfTimestamp()
 178          * @return bool
 179          * @since 1.18
 180          */
 181         function usesTimestamps() {
 182                 return false;
 183         }
 184
 185         /**
 186          * Override to sort by increasing values
 187          *
 188          * @return Boolean
 189          */
 190         function sortDescending() {
 191                 return true;
 192         }
 193
 194         /**
 195          * Is this query expensive (for some definition of expensive)? Then we
 196          * don't let it run in miser mode. $wgDisableQueryPages causes all query
 197          * pages to be declared expensive. Some query pages are always expensive.
 198          *
 199          * @return Boolean
 200          */
 201         function isExpensive() {
 202                 global $wgDisableQueryPages;
 203                 return $wgDisableQueryPages;
 204         }
 205
 206         /**
 207          * Is the output of this query cacheable? Non-cacheable expensive pages
 208          * will be disabled in miser mode and will not have their results written
 209          * to the querycache table.
 210          * @return Boolean
 211          * @since 1.18
 212          */
 213         public function isCacheable() {
 214                 return true;
 215         }
 216
 217         /**
 218          * Whether or not the output of the page in question is retrieved from
 219          * the database cache.
 220          *
 221          * @return Boolean
 222          */
 223         function isCached() {
 224                 global $wgMiserMode;
 225
 226                 return $this->isExpensive() && $wgMiserMode;
 227         }
 228
 229         /**
 230          * Sometime we dont want to build rss / atom feeds.
 231          *
 232          * @return Boolean
 233          */
 234         function isSyndicated() {
 235                 return true;
 236         }
 237
 238         /**
 239          * Formats the results of the query for display. The skin is the current
 240          * skin; you can use it for making links. The result is a single row of
 241          * result data. You should be able to grab SQL results off of it.
 242          * If the function returns false, the line output will be skipped.
 243          * @param $skin Skin
 244          * @param $result object Result row
 245          * @return mixed String or false to skip
 246          *
 247          * @param $skin Skin object
 248          * @param $result Object: database row
 249          */
 250         abstract function formatResult( $skin, $result );
 251
 252         /**
 253          * The content returned by this function will be output before any result
 254          *
 255          * @return String
 256          */
 257         function getPageHeader() {
 258                 return '';
 259         }
 260
 261         /**
 262          * If using extra form wheely-dealies, return a set of parameters here
 263          * as an associative array. They will be encoded and added to the paging
 264          * links (prev/next/lengths).
 265          *
 266          * @return Array
 267          */
 268         function linkParameters() {
 269                 return array();
 270         }
 271
 272         /**
 273          * Some special pages (for example SpecialListusers) might not return the
 274          * current object formatted, but return the previous one instead.
 275          * Setting this to return true will ensure formatResult() is called
 276          * one more time to make sure that the very last result is formatted
 277          * as well.
 278          * @return bool
 279          */
 280         function tryLastResult() {
 281                 return false;
 282         }
 283
 284         /**
 285          * Clear the cache and save new results
 286          *
 287          * @param $limit Integer: limit for SQL statement
 288          * @param $ignoreErrors Boolean: whether to ignore database errors
 289          * @return bool|int
 290          */
 291         function recache( $limit, $ignoreErrors = true ) {
 292                 if ( !$this->isCacheable() ) {
 293                         return 0;
 294                 }
 295
 296                 $fname = get_class( $this ) . '::recache';
 297                 $dbw = wfGetDB( DB_MASTER );
 298                 $dbr = wfGetDB( DB_SLAVE, array( $this->getName(), __METHOD__, 'vslow' ) );
 299                 if ( !$dbw || !$dbr ) {
 300                         return false;
 301                 }
 302
 303                 if ( $ignoreErrors ) {
 304                         $ignoreW = $dbw->ignoreErrors( true );
 305                         $ignoreR = $dbr->ignoreErrors( true );
 306                 }
 307
 308                 # Clear out any old cached data
 309                 $dbw->delete( 'querycache', array( 'qc_type' => $this->getName() ), $fname );
 310                 # Do query
 311                 $res = $this->reallyDoQuery( $limit, false );
 312                 $num = false;
 313                 if ( $res ) {
 314                         $num = $res->numRows();
 315                         # Fetch results
 316                         $vals = array();
 317                         while ( $res && $row = $dbr->fetchObject( $res ) ) {
 318                                 if ( isset( $row->value ) ) {
 319                                         if ( $this->usesTimestamps() ) {
 320                                                 $value = wfTimestamp( TS_UNIX,
 321                                                         $row->value );
 322                                         } else {
 323                                                 $value = intval( $row->value ); // @bug 14414
 324                                         }
 325                                 } else {
 326                                         $value = 0;
 327                                 }
 328
 329                                 $vals[] = array( 'qc_type' => $this->getName(),
 330                                                 'qc_namespace' => $row->namespace,
 331                                                 'qc_title' => $row->title,
 332                                                 'qc_value' => $value );
 333                         }
 334
 335                         # Save results into the querycache table on the master
 336                         if ( count( $vals ) ) {
 337                                 if ( !$dbw->insert( 'querycache', $vals, __METHOD__ ) ) {
 338                                         // Set result to false to indicate error
 339                                         $num = false;
 340                                 }
 341                         }
 342                         if ( $ignoreErrors ) {
 343                                 $dbw->ignoreErrors( $ignoreW );
 344                                 $dbr->ignoreErrors( $ignoreR );
 345                         }
 346
 347                         # Update the querycache_info record for the page
 348                         $dbw->delete( 'querycache_info', array( 'qci_type' => $this->getName() ), $fname );
 349                         $dbw->insert( 'querycache_info', array( 'qci_type' => $this->getName(), 'qci_timestamp' => $dbw->timestamp() ), $fname );
 350
 351                 }
 352                 return $num;
 353         }
 354
 355         /**
 356          * Run the query and return the result
 357          * @param $limit mixed Numerical limit or false for no limit
 358          * @param $offset mixed Numerical offset or false for no offset
 359          * @return ResultWrapper
 360          * @since 1.18
 361          */
 362         function reallyDoQuery( $limit, $offset = false ) {
 363                 $fname = get_class( $this ) . "::reallyDoQuery";
 364                 $dbr = wfGetDB( DB_SLAVE );
 365                 $query = $this->getQueryInfo();
 366                 $order = $this->getOrderFields();
 367                 if ( $this->sortDescending() ) {
 368                         foreach ( $order as &$field ) {
 369                                 $field .= ' DESC';
 370                         }
 371                 }
 372                 if ( is_array( $query ) ) {
 373                         $tables = isset( $query['tables'] ) ? (array)$query['tables'] : array();
 374                         $fields = isset( $query['fields'] ) ? (array)$query['fields'] : array();
 375                         $conds = isset( $query['conds'] ) ? (array)$query['conds'] : array();
 376                         $options = isset( $query['options'] ) ? (array)$query['options'] : array();
 377                         $join_conds = isset( $query['join_conds'] ) ? (array)$query['join_conds'] : array();
 378                         if ( count( $order ) ) {
 379                                 $options['ORDER BY'] = $order;
 380                         }
 381                         if ( $limit !== false ) {
 382                                 $options['LIMIT'] = intval( $limit );
 383                         }
 384                         if ( $offset !== false ) {
 385                                 $options['OFFSET'] = intval( $offset );
 386                         }
 387
 388                         $res = $dbr->select( $tables, $fields, $conds, $fname,
 389                                         $options, $join_conds
 390                         );
 391                 } else {
 392                         // Old-fashioned raw SQL style, deprecated
 393                         $sql = $this->getSQL();
 394                         $sql .= ' ORDER BY ' . implode( ', ', $order );
 395                         $sql = $dbr->limitResult( $sql, $limit, $offset );
 396                         $res = $dbr->query( $sql, $fname );
 397                 }
 398                 return $dbr->resultObject( $res );
 399         }
 400
 401         /**
 402          * Somewhat deprecated, you probably want to be using execute()
 403          * @return ResultWrapper
 404          */
 405         function doQuery( $offset = false, $limit = false ) {
 406                 if ( $this->isCached() && $this->isCacheable() ) {
 407                         return $this->fetchFromCache( $limit, $offset );
 408                 } else {
 409                         return $this->reallyDoQuery( $limit, $offset );
 410                 }
 411         }
 412
 413         /**
 414          * Fetch the query results from the query cache
 415          * @param $limit mixed Numerical limit or false for no limit
 416          * @param $offset mixed Numerical offset or false for no offset
 417          * @return ResultWrapper
 418          * @since 1.18
 419          */
 420         function fetchFromCache( $limit, $offset = false ) {
 421                 $dbr = wfGetDB( DB_SLAVE );
 422                 $options = array ();
 423                 if ( $limit !== false ) {
 424                         $options['LIMIT'] = intval( $limit );
 425                 }
 426                 if ( $offset !== false ) {
 427                         $options['OFFSET'] = intval( $offset );
 428                 }
 429                 if ( $this->sortDescending() ) {
 430                         $options['ORDER BY'] = 'qc_value DESC';
 431                 } else {
 432                         $options['ORDER BY'] = 'qc_value ASC';
 433                 }
 434                 $res = $dbr->select( 'querycache', array( 'qc_type',
 435                                 'qc_namespace AS namespace',
 436                                 'qc_title AS title',
 437                                 'qc_value AS value' ),
 438                                 array( 'qc_type' => $this->getName() ),
 439                                 __METHOD__, $options
 440                 );
 441                 return $dbr->resultObject( $res );
 442         }
 443
 444         public function getCachedTimestamp() {
 445                 if ( is_null( $this->cachedTimestamp ) ) {
 446                         $dbr = wfGetDB( DB_SLAVE );
 447                         $fname = get_class( $this ) . '::getCachedTimestamp';
 448                         $this->cachedTimestamp = $dbr->selectField( 'querycache_info', 'qci_timestamp',
 449                                 array( 'qci_type' => $this->getName() ), $fname );
 450                 }
 451                 return $this->cachedTimestamp;
 452         }
 453
 454         /**
 455          * This is the actual workhorse. It does everything needed to make a
 456          * real, honest-to-gosh query page.
 457          * @return int
 458          */
 459         function execute( $par ) {
 460                 global $wgQueryCacheLimit, $wgDisableQueryPageUpdate;
 461
 462                 $user = $this->getUser();
 463                 if ( !$this->userCanExecute( $user ) ) {
 464                         $this->displayRestrictionError();
 465                         return;
 466                 }
 467
 468                 $this->setHeaders();
 469                 $this->outputHeader();
 470
 471                 $out = $this->getOutput();
 472
 473                 if ( $this->isCached() && !$this->isCacheable() ) {
 474                         $out->addWikiMsg( 'querypage-disabled' );
 475                         return 0;
 476                 }
 477
 478                 $out->setSyndicated( $this->isSyndicated() );
 479
 480                 if ( $this->limit == 0 && $this->offset == 0 ) {
 481                         list( $this->limit, $this->offset ) = $this->getRequest()->getLimitOffset();
 482                 }
 483
 484                 // TODO: Use doQuery()
 485                 if ( !$this->isCached() ) {
 486                         $res = $this->reallyDoQuery( $this->limit, $this->offset );
 487                 } else {
 488                         # Get the cached result
 489                         $res = $this->fetchFromCache( $this->limit, $this->offset );
 490                         if ( !$this->listoutput ) {
 491
 492                                 # Fetch the timestamp of this update
 493                                 $ts = $this->getCachedTimestamp();
 494                                 $lang = $this->getLanguage();
 495                                 $maxResults = $lang->formatNum( $wgQueryCacheLimit );
 496
 497                                 if ( $ts ) {
 498                                         $updated = $lang->userTimeAndDate( $ts, $user );
 499                                         $updateddate = $lang->userDate( $ts, $user );
 500                                         $updatedtime = $lang->userTime( $ts, $user );
 501                                         $out->addMeta( 'Data-Cache-Time', $ts );
 502                                         $out->addJsConfigVars( 'dataCacheTime', $ts );
 503                                         $out->addWikiMsg( 'perfcachedts', $updated, $updateddate, $updatedtime, $maxResults );
 504                                 } else {
 505                                         $out->addWikiMsg( 'perfcached', $maxResults );
 506                                 }
 507
 508                                 # If updates on this page have been disabled, let the user know
 509                                 # that the data set won't be refreshed for now
 510                                 if ( is_array( $wgDisableQueryPageUpdate ) && in_array( $this->getName(), $wgDisableQueryPageUpdate ) ) {
 511                                         $out->wrapWikiMsg( "<div class=\"mw-querypage-no-updates\">\n$1\n</div>", 'querypage-no-updates' );
 512                                 }
 513                         }
 514                 }
 515
 516                 $this->numRows = $res->numRows();
 517
 518                 $dbr = wfGetDB( DB_SLAVE );
 519                 $this->preprocessResults( $dbr, $res );
 520
 521                 $out->addHTML( Xml::openElement( 'div', array( 'class' => 'mw-spcontent' ) ) );
 522
 523                 # Top header and navigation
 524                 if ( $this->shownavigation ) {
 525                         $out->addHTML( $this->getPageHeader() );
 526                         if ( $this->numRows > 0 ) {
 527                                 $out->addHTML( $this->msg( 'showingresults' )->numParams(
 528                                         $this->numRows, $this->offset + 1 )->parseAsBlock() );
 529                                 # Disable the "next" link when we reach the end
 530                                 $paging = $this->getLanguage()->viewPrevNext( $this->getTitle( $par ), $this->offset,
 531                                         $this->limit, $this->linkParameters(), ( $this->numRows < $this->limit ) );
 532                                 $out->addHTML( '<p>' . $paging . '</p>' );
 533                         } else {
 534                                 # No results to show, so don't bother with "showing X of Y" etc.
 535                                 # -- just let the user know and give up now
 536                                 $out->addWikiMsg( 'specialpage-empty' );
 537                                 $out->addHTML( Xml::closeElement( 'div' ) );
 538                                 return;
 539                         }
 540                 }
 541
 542                 # The actual results; specialist subclasses will want to handle this
 543                 # with more than a straight list, so we hand them the info, plus
 544                 # an OutputPage, and let them get on with it
 545                 $this->outputResults( $out,
 546                         $this->getSkin(),
 547                         $dbr, # Should use a ResultWrapper for this
 548                         $res,
 549                         $this->numRows,
 550                         $this->offset );
 551
 552                 # Repeat the paging links at the bottom
 553                 if ( $this->shownavigation ) {
 554                         $out->addHTML( '<p>' . $paging . '</p>' );
 555                 }
 556
 557                 $out->addHTML( Xml::closeElement( 'div' ) );
 558
 559                 return $this->numRows;
 560         }
 561
 562         /**
 563          * Format and output report results using the given information plus
 564          * OutputPage
 565          *
 566          * @param $out OutputPage to print to
 567          * @param $skin Skin: user skin to use
 568          * @param $dbr Database (read) connection to use
 569          * @param $res Integer: result pointer
 570          * @param $num Integer: number of available result rows
 571          * @param $offset Integer: paging offset
 572          */
 573         protected function outputResults( $out, $skin, $dbr, $res, $num, $offset ) {
 574                 global $wgContLang;
 575
 576                 if ( $num > 0 ) {
 577                         $html = array();
 578                         if ( !$this->listoutput ) {
 579                                 $html[] = $this->openList( $offset );
 580                         }
 581
 582                         # $res might contain the whole 1,000 rows, so we read up to
 583                         # $num [should update this to use a Pager]
 584                         for ( $i = 0; $i < $num && $row = $dbr->fetchObject( $res ); $i++ ) {
 585                                 $line = $this->formatResult( $skin, $row );
 586                                 if ( $line ) {
 587                                         $attr = ( isset( $row->usepatrol ) && $row->usepatrol && $row->patrolled == 0 )
 588                                                 ? ' class="not-patrolled"'
 589                                                 : '';
 590                                         $html[] = $this->listoutput
 591                                                 ? $line
 592                                                 : "<li{$attr}>{$line}</li>\n";
 593                                 }
 594                         }
 595
 596                         # Flush the final result
 597                         if ( $this->tryLastResult() ) {
 598                                 $row = null;
 599                                 $line = $this->formatResult( $skin, $row );
 600                                 if ( $line ) {
 601                                         $attr = ( isset( $row->usepatrol ) && $row->usepatrol && $row->patrolled == 0 )
 602                                                 ? ' class="not-patrolled"'
 603                                                 : '';
 604                                         $html[] = $this->listoutput
 605                                                 ? $line
 606                                                 : "<li{$attr}>{$line}</li>\n";
 607                                 }
 608                         }
 609
 610                         if ( !$this->listoutput ) {
 611                                 $html[] = $this->closeList();
 612                         }
 613
 614                         $html = $this->listoutput
 615                                 ? $wgContLang->listToText( $html )
 616                                 : implode( '', $html );
 617
 618                         $out->addHTML( $html );
 619                 }
 620         }
 621
 622         /**
 623          * @param $offset
 624          * @return string
 625          */
 626         function openList( $offset ) {
 627                 return "\n<ol start='" . ( $offset + 1 ) . "' class='special'>\n";
 628         }
 629
 630         /**
 631          * @return string
 632          */
 633         function closeList() {
 634                 return "</ol>\n";
 635         }
 636
 637         /**
 638          * Do any necessary preprocessing of the result object.
 639          */
 640         function preprocessResults( $db, $res ) {}
 641
 642         /**
 643          * Similar to above, but packaging in a syndicated feed instead of a web page
 644          * @return bool
 645          */
 646         function doFeed( $class = '', $limit = 50 ) {
 647                 global $wgFeed, $wgFeedClasses;
 648
 649                 if ( !$wgFeed ) {
 650                         $this->getOutput()->addWikiMsg( 'feed-unavailable' );
 651                         return;
 652                 }
 653
 654                 global $wgFeedLimit;
 655                 if ( $limit > $wgFeedLimit ) {
 656                         $limit = $wgFeedLimit;
 657                 }
 658
 659                 if ( isset( $wgFeedClasses[$class] ) ) {
 660                         $feed = new $wgFeedClasses[$class](
 661                                 $this->feedTitle(),
 662                                 $this->feedDesc(),
 663                                 $this->feedUrl() );
 664                         $feed->outHeader();
 665
 666                         $res = $this->reallyDoQuery( $limit, 0 );
 667                         foreach ( $res as $obj ) {
 668                                 $item = $this->feedResult( $obj );
 669                                 if ( $item ) {
 670                                         $feed->outItem( $item );
 671                                 }
 672                         }
 673
 674                         $feed->outFooter();
 675                         return true;
 676                 } else {
 677                         return false;
 678                 }
 679         }
 680
 681         /**
 682          * Override for custom handling. If the titles/links are ok, just do
 683          * feedItemDesc()
 684          * @return FeedItem|null
 685          */
 686         function feedResult( $row ) {
 687                 if ( !isset( $row->title ) ) {
 688                         return null;
 689                 }
 690                 $title = Title::makeTitle( intval( $row->namespace ), $row->title );
 691                 if ( $title ) {
 692                         $date = isset( $row->timestamp ) ? $row->timestamp : '';
 693                         $comments = '';
 694                         if ( $title ) {
 695                                 $talkpage = $title->getTalkPage();
 696                                 $comments = $talkpage->getFullURL();
 697                         }
 698
 699                         return new FeedItem(
 700                                 $title->getPrefixedText(),
 701                                 $this->feedItemDesc( $row ),
 702                                 $title->getFullURL(),
 703                                 $date,
 704                                 $this->feedItemAuthor( $row ),
 705                                 $comments );
 706                 } else {
 707                         return null;
 708                 }
 709         }
 710
 711         function feedItemDesc( $row ) {
 712                 return isset( $row->comment ) ? htmlspecialchars( $row->comment ) : '';
 713         }
 714
 715         function feedItemAuthor( $row ) {
 716                 return isset( $row->user_text ) ? $row->user_text : '';
 717         }
 718
 719         function feedTitle() {
 720                 global $wgLanguageCode, $wgSitename;
 721                 $desc = $this->getDescription();
 722                 return "$wgSitename - $desc [$wgLanguageCode]";
 723         }
 724
 725         function feedDesc() {
 726                 return $this->msg( 'tagline' )->text();
 727         }
 728
 729         function feedUrl() {
 730                 return $this->getTitle()->getFullURL();
 731         }
 732 }
 733
 734 /**
 735  * Class definition for a wanted query page like
 736  * WantedPages, WantedTemplates, etc
 737  */
 738 abstract class WantedQueryPage extends QueryPage {
 739
 740         function isExpensive() {
 741                 return true;
 742         }
 743
 744         function isSyndicated() {
 745                 return false;
 746         }
 747
 748         /**
 749          * Cache page existence for performance
 750          */
 751         function preprocessResults( $db, $res ) {
 752                 if ( !$res->numRows() ) {
 753                         return;
 754                 }
 755
 756                 $batch = new LinkBatch;
 757                 foreach ( $res as $row ) {
 758                         $batch->add( $row->namespace, $row->title );
 759                 }
 760                 $batch->execute();
 761
 762                 // Back to start for display
 763                 $res->seek( 0 );
 764         }
 765
 766         /**
 767          * Should formatResult() always check page existence, even if
 768          * the results are fresh?  This is a (hopefully temporary)
 769          * kluge for Special:WantedFiles, which may contain false
 770          * positives for files that exist e.g. in a shared repo (bug
 771          * 6220).
 772          * @return bool
 773          */
 774         function forceExistenceCheck() {
 775                 return false;
 776         }
 777
 778         /**
 779          * Format an individual result
 780          *
 781          * @param $skin Skin to use for UI elements
 782          * @param $result Result row
 783          * @return string
 784          */
 785         public function formatResult( $skin, $result ) {
 786                 $title = Title::makeTitleSafe( $result->namespace, $result->title );
 787                 if ( $title instanceof Title ) {
 788                         if ( $this->isCached() || $this->forceExistenceCheck() ) {
 789                                 $pageLink = $title->isKnown()
 790                                         ? '<del>' . Linker::link( $title ) . '</del>'
 791                                         : Linker::link(
 792                                                 $title,
 793                                                 null,
 794                                                 array(),
 795                                                 array(),
 796                                                 array( 'broken' )
 797                                         );
 798                         } else {
 799                                 $pageLink = Linker::link(
 800                                         $title,
 801                                         null,
 802                                         array(),
 803                                         array(),
 804                                         array( 'broken' )
 805                                 );
 806                         }
 807                         return $this->getLanguage()->specialList( $pageLink, $this->makeWlhLink( $title, $result ) );
 808                 } else {
 809                         return $this->msg( 'wantedpages-badtitle', $result->title )->escaped();
 810                 }
 811         }
 812
 813         /**
 814          * Make a "what links here" link for a given title
 815          *
 816          * @param $title Title to make the link for
 817          * @param $result Object: result row
 818          * @return string
 819          */
 820         private function makeWlhLink( $title, $result ) {
 821                 $wlh = SpecialPage::getTitleFor( 'Whatlinkshere', $title->getPrefixedText() );
 822                 $label = $this->msg( 'nlinks' )->numParams( $result->value )->escaped();
 823                 return Linker::link( $wlh, $label );
 824         }
 825 }