includes/specialpage/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 use MediaWiki\MediaWikiServices;
  25 use Wikimedia\Rdbms\IResultWrapper;
  26 use Wikimedia\Rdbms\IDatabase;
  27 use Wikimedia\Rdbms\DBError;
  28
  29 /**
  30  * This is a class for doing query pages; since they're almost all the same,
  31  * we factor out some of the functionality into a superclass, and let
  32  * subclasses derive from it.
  33  * @ingroup SpecialPage
  34  */
  35 abstract class QueryPage extends SpecialPage {
  36         /** @var bool Whether or not we want plain listoutput rather than an ordered list */
  37         protected $listoutput = false;
  38
  39         /** @var int The offset and limit in use, as passed to the query() function */
  40         protected $offset = 0;
  41
  42         /** @var int */
  43         protected $limit = 0;
  44
  45         /**
  46          * The number of rows returned by the query. Reading this variable
  47          * only makes sense in functions that are run after the query has been
  48          * done, such as preprocessResults() and formatRow().
  49          *
  50          * @var int
  51          */
  52         protected $numRows;
  53
  54         /**
  55          * @var string|null
  56          */
  57         protected $cachedTimestamp = null;
  58
  59         /**
  60          * @var bool Whether to show prev/next links
  61          */
  62         protected $shownavigation = true;
  63
  64         /**
  65          * Get a list of query page classes and their associated special pages,
  66          * for periodic updates.
  67          *
  68          * DO NOT CHANGE THIS LIST without testing that
  69          * maintenance/updateSpecialPages.php still works.
  70          *
  71          * @return string[][]
  72          */
  73         public static function getPages() {
  74                 static $qp = null;
  75
  76                 if ( $qp === null ) {
  77                         // QueryPage subclass, Special page name
  78                         $qp = [
  79                                 [ AncientPagesPage::class, 'Ancientpages' ],
  80                                 [ BrokenRedirectsPage::class, 'BrokenRedirects' ],
  81                                 [ DeadendPagesPage::class, 'Deadendpages' ],
  82                                 [ DoubleRedirectsPage::class, 'DoubleRedirects' ],
  83                                 [ FileDuplicateSearchPage::class, 'FileDuplicateSearch' ],
  84                                 [ ListDuplicatedFilesPage::class, 'ListDuplicatedFiles' ],
  85                                 [ LinkSearchPage::class, 'LinkSearch' ],
  86                                 [ ListredirectsPage::class, 'Listredirects' ],
  87                                 [ LonelyPagesPage::class, 'Lonelypages' ],
  88                                 [ LongPagesPage::class, 'Longpages' ],
  89                                 [ MediaStatisticsPage::class, 'MediaStatistics' ],
  90                                 [ MIMEsearchPage::class, 'MIMEsearch' ],
  91                                 [ MostcategoriesPage::class, 'Mostcategories' ],
  92                                 [ MostimagesPage::class, 'Mostimages' ],
  93                                 [ MostinterwikisPage::class, 'Mostinterwikis' ],
  94                                 [ MostlinkedCategoriesPage::class, 'Mostlinkedcategories' ],
  95                                 [ MostlinkedTemplatesPage::class, 'Mostlinkedtemplates' ],
  96                                 [ MostlinkedPage::class, 'Mostlinked' ],
  97                                 [ MostrevisionsPage::class, 'Mostrevisions' ],
  98                                 [ FewestrevisionsPage::class, 'Fewestrevisions' ],
  99                                 [ ShortPagesPage::class, 'Shortpages' ],
 100                                 [ UncategorizedCategoriesPage::class, 'Uncategorizedcategories' ],
 101                                 [ UncategorizedPagesPage::class, 'Uncategorizedpages' ],
 102                                 [ UncategorizedImagesPage::class, 'Uncategorizedimages' ],
 103                                 [ UncategorizedTemplatesPage::class, 'Uncategorizedtemplates' ],
 104                                 [ UnusedCategoriesPage::class, 'Unusedcategories' ],
 105                                 [ UnusedimagesPage::class, 'Unusedimages' ],
 106                                 [ WantedCategoriesPage::class, 'Wantedcategories' ],
 107                                 [ WantedFilesPage::class, 'Wantedfiles' ],
 108                                 [ WantedPagesPage::class, 'Wantedpages' ],
 109                                 [ WantedTemplatesPage::class, 'Wantedtemplates' ],
 110                                 [ UnwatchedpagesPage::class, 'Unwatchedpages' ],
 111                                 [ UnusedtemplatesPage::class, 'Unusedtemplates' ],
 112                                 [ WithoutInterwikiPage::class, 'Withoutinterwiki' ],
 113                         ];
 114                         Hooks::run( 'wgQueryPages', [ &$qp ] );
 115                 }
 116
 117                 return $qp;
 118         }
 119
 120         /**
 121          * A mutator for $this->listoutput;
 122          *
 123          * @param bool $bool
 124          */
 125         function setListoutput( $bool ) {
 126                 $this->listoutput = $bool;
 127         }
 128
 129         /**
 130          * Subclasses return an SQL query here, formatted as an array with the
 131          * following keys:
 132          *    tables => Table(s) for passing to Database::select()
 133          *    fields => Field(s) for passing to Database::select(), may be *
 134          *    conds => WHERE conditions
 135          *    options => options
 136          *    join_conds => JOIN conditions
 137          *
 138          * Note that the query itself should return the following three columns:
 139          * 'namespace', 'title', and 'value'. 'value' is used for sorting.
 140          *
 141          * These may be stored in the querycache table for expensive queries,
 142          * and that cached data will be returned sometimes, so the presence of
 143          * extra fields can't be relied upon. The cached 'value' column will be
 144          * an integer; non-numeric values are useful only for sorting the
 145          * initial query (except if they're timestamps, see usesTimestamps()).
 146          *
 147          * Don't include an ORDER or LIMIT clause, they will be added.
 148          *
 149          * If this function is not overridden or returns something other than
 150          * an array, getSQL() will be used instead. This is for backwards
 151          * compatibility only and is strongly deprecated.
 152          * @return array
 153          * @since 1.18
 154          */
 155         public function getQueryInfo() {
 156                 return null;
 157         }
 158
 159         /**
 160          * For back-compat, subclasses may return a raw SQL query here, as a string.
 161          * This is strongly deprecated; getQueryInfo() should be overridden instead.
 162          * @throws MWException
 163          * @return string
 164          */
 165         function getSQL() {
 166                 /* Implement getQueryInfo() instead */
 167                 throw new MWException( "Bug in a QueryPage: doesn't implement getQueryInfo() nor "
 168                         . "getQuery() properly" );
 169         }
 170
 171         /**
 172          * Subclasses return an array of fields to order by here. Don't append
 173          * DESC to the field names, that'll be done automatically if
 174          * sortDescending() returns true.
 175          * @return string[]
 176          * @since 1.18
 177          */
 178         function getOrderFields() {
 179                 return [ 'value' ];
 180         }
 181
 182         /**
 183          * Does this query return timestamps rather than integers in its
 184          * 'value' field? If true, this class will convert 'value' to a
 185          * UNIX timestamp for caching.
 186          * NOTE: formatRow() may get timestamps in TS_MW (mysql), TS_DB (pgsql)
 187          *       or TS_UNIX (querycache) format, so be sure to always run them
 188          *       through wfTimestamp()
 189          * @return bool
 190          * @since 1.18
 191          */
 192         public function usesTimestamps() {
 193                 return false;
 194         }
 195
 196         /**
 197          * Override to sort by increasing values
 198          *
 199          * @return bool
 200          */
 201         function sortDescending() {
 202                 return true;
 203         }
 204
 205         /**
 206          * Is this query expensive (for some definition of expensive)? Then we
 207          * don't let it run in miser mode. $wgDisableQueryPages causes all query
 208          * pages to be declared expensive. Some query pages are always expensive.
 209          *
 210          * @return bool
 211          */
 212         public function isExpensive() {
 213                 return $this->getConfig()->get( 'DisableQueryPages' );
 214         }
 215
 216         /**
 217          * Is the output of this query cacheable? Non-cacheable expensive pages
 218          * will be disabled in miser mode and will not have their results written
 219          * to the querycache table.
 220          * @return bool
 221          * @since 1.18
 222          */
 223         public function isCacheable() {
 224                 return true;
 225         }
 226
 227         /**
 228          * Whether or not the output of the page in question is retrieved from
 229          * the database cache.
 230          *
 231          * @return bool
 232          */
 233         public function isCached() {
 234                 return $this->isExpensive() && $this->getConfig()->get( 'MiserMode' );
 235         }
 236
 237         /**
 238          * Sometime we don't want to build rss / atom feeds.
 239          *
 240          * @return bool
 241          */
 242         function isSyndicated() {
 243                 return true;
 244         }
 245
 246         /**
 247          * Formats the results of the query for display. The skin is the current
 248          * skin; you can use it for making links. The result is a single row of
 249          * result data. You should be able to grab SQL results off of it.
 250          * If the function returns false, the line output will be skipped.
 251          * @param Skin $skin
 252          * @param object $result Result row
 253          * @return string|bool String or false to skip
 254          */
 255         abstract function formatResult( $skin, $result );
 256
 257         /**
 258          * The content returned by this function will be output before any result
 259          *
 260          * @return string
 261          */
 262         function getPageHeader() {
 263                 return '';
 264         }
 265
 266         /**
 267          * Outputs some kind of an informative message (via OutputPage) to let the
 268          * user know that the query returned nothing and thus there's nothing to
 269          * show.
 270          *
 271          * @since 1.26
 272          */
 273         protected function showEmptyText() {
 274                 $this->getOutput()->addWikiMsg( 'specialpage-empty' );
 275         }
 276
 277         /**
 278          * If using extra form wheely-dealies, return a set of parameters here
 279          * as an associative array. They will be encoded and added to the paging
 280          * links (prev/next/lengths).
 281          *
 282          * @return array
 283          */
 284         function linkParameters() {
 285                 return [];
 286         }
 287
 288         /**
 289          * Some special pages (for example SpecialListusers used to) might not return the
 290          * current object formatted, but return the previous one instead.
 291          * Setting this to return true will ensure formatResult() is called
 292          * one more time to make sure that the very last result is formatted
 293          * as well.
 294          *
 295          * @deprecated since 1.27
 296          *
 297          * @return bool
 298          */
 299         function tryLastResult() {
 300                 return false;
 301         }
 302
 303         /**
 304          * Clear the cache and save new results
 305          *
 306          * @param int|bool $limit Limit for SQL statement
 307          * @param bool $ignoreErrors Whether to ignore database errors
 308          * @throws DBError|Exception
 309          * @return bool|int
 310          */
 311         public function recache( $limit, $ignoreErrors = true ) {
 312                 if ( !$this->isCacheable() ) {
 313                         return 0;
 314                 }
 315
 316                 $fname = static::class . '::recache';
 317                 $dbw = wfGetDB( DB_MASTER );
 318                 if ( !$dbw ) {
 319                         return false;
 320                 }
 321
 322                 try {
 323                         # Do query
 324                         $res = $this->reallyDoQuery( $limit, false );
 325                         $num = false;
 326                         if ( $res ) {
 327                                 $num = $res->numRows();
 328                                 # Fetch results
 329                                 $vals = [];
 330                                 foreach ( $res as $row ) {
 331                                         if ( isset( $row->value ) ) {
 332                                                 if ( $this->usesTimestamps() ) {
 333                                                         $value = wfTimestamp( TS_UNIX,
 334                                                                 $row->value );
 335                                                 } else {
 336                                                         $value = intval( $row->value ); // T16414
 337                                                 }
 338                                         } else {
 339                                                 $value = 0;
 340                                         }
 341
 342                                         $vals[] = [
 343                                                 'qc_type' => $this->getName(),
 344                                                 'qc_namespace' => $row->namespace,
 345                                                 'qc_title' => $row->title,
 346                                                 'qc_value' => $value
 347                                         ];
 348                                 }
 349
 350                                 $dbw->doAtomicSection(
 351                                         __METHOD__,
 352                                         function ( IDatabase $dbw, $fname ) use ( $vals ) {
 353                                                 # Clear out any old cached data
 354                                                 $dbw->delete( 'querycache',
 355                                                         [ 'qc_type' => $this->getName() ],
 356                                                         $fname
 357                                                 );
 358                                                 # Save results into the querycache table on the master
 359                                                 if ( count( $vals ) ) {
 360                                                         $dbw->insert( 'querycache', $vals, $fname );
 361                                                 }
 362                                                 # Update the querycache_info record for the page
 363                                                 $dbw->delete( 'querycache_info',
 364                                                         [ 'qci_type' => $this->getName() ],
 365                                                         $fname
 366                                                 );
 367                                                 $dbw->insert( 'querycache_info',
 368                                                         [ 'qci_type' => $this->getName(),
 369                                                                 'qci_timestamp' => $dbw->timestamp() ],
 370                                                         $fname
 371                                                 );
 372                                         }
 373                                 );
 374                         }
 375                 } catch ( DBError $e ) {
 376                         if ( !$ignoreErrors ) {
 377                                 throw $e; // report query error
 378                         }
 379                         $num = false; // set result to false to indicate error
 380                 }
 381
 382                 return $num;
 383         }
 384
 385         /**
 386          * Get a DB connection to be used for slow recache queries
 387          * @return \Wikimedia\Rdbms\Database
 388          */
 389         function getRecacheDB() {
 390                 return wfGetDB( DB_REPLICA, [ $this->getName(), 'QueryPage::recache', 'vslow' ] );
 391         }
 392
 393         /**
 394          * Run the query and return the result
 395          * @param int|bool $limit Numerical limit or false for no limit
 396          * @param int|bool $offset Numerical offset or false for no offset
 397          * @return IResultWrapper
 398          * @since 1.18
 399          */
 400         public function reallyDoQuery( $limit, $offset = false ) {
 401                 $fname = static::class . '::reallyDoQuery';
 402                 $dbr = $this->getRecacheDB();
 403                 $query = $this->getQueryInfo();
 404                 $order = $this->getOrderFields();
 405
 406                 if ( $this->sortDescending() ) {
 407                         foreach ( $order as &$field ) {
 408                                 $field .= ' DESC';
 409                         }
 410                 }
 411
 412                 if ( is_array( $query ) ) {
 413                         $tables = isset( $query['tables'] ) ? (array)$query['tables'] : [];
 414                         $fields = isset( $query['fields'] ) ? (array)$query['fields'] : [];
 415                         $conds = isset( $query['conds'] ) ? (array)$query['conds'] : [];
 416                         $options = isset( $query['options'] ) ? (array)$query['options'] : [];
 417                         $join_conds = isset( $query['join_conds'] ) ? (array)$query['join_conds'] : [];
 418
 419                         if ( $order ) {
 420                                 $options['ORDER BY'] = $order;
 421                         }
 422
 423                         if ( $limit !== false ) {
 424                                 $options['LIMIT'] = intval( $limit );
 425                         }
 426
 427                         if ( $offset !== false ) {
 428                                 $options['OFFSET'] = intval( $offset );
 429                         }
 430
 431                         $res = $dbr->select( $tables, $fields, $conds, $fname,
 432                                         $options, $join_conds
 433                         );
 434                 } else {
 435                         // Old-fashioned raw SQL style, deprecated
 436                         $sql = $this->getSQL();
 437                         $sql .= ' ORDER BY ' . implode( ', ', $order );
 438                         $sql = $dbr->limitResult( $sql, $limit, $offset );
 439                         $res = $dbr->query( $sql, $fname );
 440                 }
 441
 442                 return $res;
 443         }
 444
 445         /**
 446          * Somewhat deprecated, you probably want to be using execute()
 447          * @param int|bool $offset
 448          * @param int|bool $limit
 449          * @return IResultWrapper
 450          */
 451         public function doQuery( $offset = false, $limit = false ) {
 452                 if ( $this->isCached() && $this->isCacheable() ) {
 453                         return $this->fetchFromCache( $limit, $offset );
 454                 } else {
 455                         return $this->reallyDoQuery( $limit, $offset );
 456                 }
 457         }
 458
 459         /**
 460          * Fetch the query results from the query cache
 461          * @param int|bool $limit Numerical limit or false for no limit
 462          * @param int|bool $offset Numerical offset or false for no offset
 463          * @return IResultWrapper
 464          * @since 1.18
 465          */
 466         public function fetchFromCache( $limit, $offset = false ) {
 467                 $dbr = wfGetDB( DB_REPLICA );
 468                 $options = [];
 469
 470                 if ( $limit !== false ) {
 471                         $options['LIMIT'] = intval( $limit );
 472                 }
 473
 474                 if ( $offset !== false ) {
 475                         $options['OFFSET'] = intval( $offset );
 476                 }
 477
 478                 $order = $this->getCacheOrderFields();
 479                 if ( $this->sortDescending() ) {
 480                         foreach ( $order as &$field ) {
 481                                 $field .= " DESC";
 482                         }
 483                 }
 484                 if ( $order ) {
 485                         $options['ORDER BY'] = $order;
 486                 }
 487
 488                 return $dbr->select( 'querycache',
 489                                 [ 'qc_type',
 490                                 'namespace' => 'qc_namespace',
 491                                 'title' => 'qc_title',
 492                                 'value' => 'qc_value' ],
 493                                 [ 'qc_type' => $this->getName() ],
 494                                 __METHOD__,
 495                                 $options
 496                 );
 497         }
 498
 499         /**
 500          * Return the order fields for fetchFromCache. Default is to always use
 501          * "ORDER BY value" which was the default prior to this function.
 502          * @return array
 503          * @since 1.29
 504          */
 505         function getCacheOrderFields() {
 506                 return [ 'value' ];
 507         }
 508
 509         /**
 510          * @return string
 511          */
 512         public function getCachedTimestamp() {
 513                 if ( is_null( $this->cachedTimestamp ) ) {
 514                         $dbr = wfGetDB( DB_REPLICA );
 515                         $fname = static::class . '::getCachedTimestamp';
 516                         $this->cachedTimestamp = $dbr->selectField( 'querycache_info', 'qci_timestamp',
 517                                 [ 'qci_type' => $this->getName() ], $fname );
 518                 }
 519                 return $this->cachedTimestamp;
 520         }
 521
 522         /**
 523          * Returns limit and offset, as returned by $this->getRequest()->getLimitOffset().
 524          * Subclasses may override this to further restrict or modify limit and offset.
 525          *
 526          * @note Restricts the offset parameter, as most query pages have inefficient paging
 527          *
 528          * Its generally expected that the returned limit will not be 0, and the returned
 529          * offset will be less than the max results.
 530          *
 531          * @since 1.26
 532          * @return int[] list( $limit, $offset )
 533          */
 534         protected function getLimitOffset() {
 535                 list( $limit, $offset ) = $this->getRequest()->getLimitOffset();
 536                 if ( $this->getConfig()->get( 'MiserMode' ) ) {
 537                         $maxResults = $this->getMaxResults();
 538                         // Can't display more than max results on a page
 539                         $limit = min( $limit, $maxResults );
 540                         // Can't skip over more than the end of $maxResults
 541                         $offset = min( $offset, $maxResults + 1 );
 542                 }
 543                 return [ $limit, $offset ];
 544         }
 545
 546         /**
 547          * What is limit to fetch from DB
 548          *
 549          * Used to make it appear the DB stores less results then it actually does
 550          * @param int $uiLimit Limit from UI
 551          * @param int $uiOffset Offset from UI
 552          * @return int Limit to use for DB (not including extra row to see if at end)
 553          */
 554         protected function getDBLimit( $uiLimit, $uiOffset ) {
 555                 $maxResults = $this->getMaxResults();
 556                 if ( $this->getConfig()->get( 'MiserMode' ) ) {
 557                         $limit = min( $uiLimit + 1, $maxResults - $uiOffset );
 558                         return max( $limit, 0 );
 559                 } else {
 560                         return $uiLimit + 1;
 561                 }
 562         }
 563
 564         /**
 565          * Get max number of results we can return in miser mode.
 566          *
 567          * Most QueryPage subclasses use inefficient paging, so limit the max amount we return
 568          * This matters for uncached query pages that might otherwise accept an offset of 3 million
 569          *
 570          * @since 1.27
 571          * @return int
 572          */
 573         protected function getMaxResults() {
 574                 // Max of 10000, unless we store more than 10000 in query cache.
 575                 return max( $this->getConfig()->get( 'QueryCacheLimit' ), 10000 );
 576         }
 577
 578         /**
 579          * This is the actual workhorse. It does everything needed to make a
 580          * real, honest-to-gosh query page.
 581          * @param string|null $par
 582          */
 583         public function execute( $par ) {
 584                 $user = $this->getUser();
 585                 if ( !$this->userCanExecute( $user ) ) {
 586                         $this->displayRestrictionError();
 587                         return;
 588                 }
 589
 590                 $this->setHeaders();
 591                 $this->outputHeader();
 592
 593                 $out = $this->getOutput();
 594
 595                 if ( $this->isCached() && !$this->isCacheable() ) {
 596                         $out->addWikiMsg( 'querypage-disabled' );
 597                         return;
 598                 }
 599
 600                 $out->setSyndicated( $this->isSyndicated() );
 601
 602                 if ( $this->limit == 0 && $this->offset == 0 ) {
 603                         list( $this->limit, $this->offset ) = $this->getLimitOffset();
 604                 }
 605                 $dbLimit = $this->getDBLimit( $this->limit, $this->offset );
 606                 // @todo Use doQuery()
 607                 if ( !$this->isCached() ) {
 608                         # select one extra row for navigation
 609                         $res = $this->reallyDoQuery( $dbLimit, $this->offset );
 610                 } else {
 611                         # Get the cached result, select one extra row for navigation
 612                         $res = $this->fetchFromCache( $dbLimit, $this->offset );
 613                         if ( !$this->listoutput ) {
 614                                 # Fetch the timestamp of this update
 615                                 $ts = $this->getCachedTimestamp();
 616                                 $lang = $this->getLanguage();
 617                                 $maxResults = $lang->formatNum( $this->getConfig()->get( 'QueryCacheLimit' ) );
 618
 619                                 if ( $ts ) {
 620                                         $updated = $lang->userTimeAndDate( $ts, $user );
 621                                         $updateddate = $lang->userDate( $ts, $user );
 622                                         $updatedtime = $lang->userTime( $ts, $user );
 623                                         $out->addMeta( 'Data-Cache-Time', $ts );
 624                                         $out->addJsConfigVars( 'dataCacheTime', $ts );
 625                                         $out->addWikiMsg( 'perfcachedts', $updated, $updateddate, $updatedtime, $maxResults );
 626                                 } else {
 627                                         $out->addWikiMsg( 'perfcached', $maxResults );
 628                                 }
 629
 630                                 # If updates on this page have been disabled, let the user know
 631                                 # that the data set won't be refreshed for now
 632                                 if ( is_array( $this->getConfig()->get( 'DisableQueryPageUpdate' ) )
 633                                         && in_array( $this->getName(), $this->getConfig()->get( 'DisableQueryPageUpdate' ) )
 634                                 ) {
 635                                         $out->wrapWikiMsg(
 636                                                 "<div class=\"mw-querypage-no-updates\">\n$1\n</div>",
 637                                                 'querypage-no-updates'
 638                                         );
 639                                 }
 640                         }
 641                 }
 642
 643                 $this->numRows = $res->numRows();
 644
 645                 $dbr = $this->getRecacheDB();
 646                 $this->preprocessResults( $dbr, $res );
 647
 648                 $out->addHTML( Xml::openElement( 'div', [ 'class' => 'mw-spcontent' ] ) );
 649
 650                 # Top header and navigation
 651                 if ( $this->shownavigation ) {
 652                         $out->addHTML( $this->getPageHeader() );
 653                         if ( $this->numRows > 0 ) {
 654                                 $out->addHTML( $this->msg( 'showingresultsinrange' )->numParams(
 655                                         min( $this->numRows, $this->limit ), # do not show the one extra row, if exist
 656                                         $this->offset + 1, ( min( $this->numRows, $this->limit ) + $this->offset ) )->parseAsBlock() );
 657                                 # Disable the "next" link when we reach the end
 658                                 $miserMaxResults = $this->getConfig()->get( 'MiserMode' )
 659                                         && ( $this->offset + $this->limit >= $this->getMaxResults() );
 660                                 $atEnd = ( $this->numRows <= $this->limit ) || $miserMaxResults;
 661                                 $paging = $this->buildPrevNextNavigation( $this->offset,
 662                                         $this->limit, $this->linkParameters(), $atEnd, $par );
 663                                 $out->addHTML( '<p>' . $paging . '</p>' );
 664                         } else {
 665                                 # No results to show, so don't bother with "showing X of Y" etc.
 666                                 # -- just let the user know and give up now
 667                                 $this->showEmptyText();
 668                                 $out->addHTML( Xml::closeElement( 'div' ) );
 669                                 return;
 670                         }
 671                 }
 672
 673                 # The actual results; specialist subclasses will want to handle this
 674                 # with more than a straight list, so we hand them the info, plus
 675                 # an OutputPage, and let them get on with it
 676                 $this->outputResults( $out,
 677                         $this->getSkin(),
 678                         $dbr, # Should use a ResultWrapper for this
 679                         $res,
 680                         min( $this->numRows, $this->limit ), # do not format the one extra row, if exist
 681                         $this->offset );
 682
 683                 # Repeat the paging links at the bottom
 684                 if ( $this->shownavigation ) {
 685                         $out->addHTML( '<p>' . $paging . '</p>' );
 686                 }
 687
 688                 $out->addHTML( Xml::closeElement( 'div' ) );
 689         }
 690
 691         /**
 692          * Format and output report results using the given information plus
 693          * OutputPage
 694          *
 695          * @param OutputPage $out OutputPage to print to
 696          * @param Skin $skin User skin to use
 697          * @param IDatabase $dbr Database (read) connection to use
 698          * @param IResultWrapper $res Result pointer
 699          * @param int $num Number of available result rows
 700          * @param int $offset Paging offset
 701          */
 702         protected function outputResults( $out, $skin, $dbr, $res, $num, $offset ) {
 703                 if ( $num > 0 ) {
 704                         $html = [];
 705                         if ( !$this->listoutput ) {
 706                                 $html[] = $this->openList( $offset );
 707                         }
 708
 709                         # $res might contain the whole 1,000 rows, so we read up to
 710                         # $num [should update this to use a Pager]
 711                         for ( $i = 0; $i < $num && $row = $res->fetchObject(); $i++ ) {
 712                                 $line = $this->formatResult( $skin, $row );
 713                                 if ( $line ) {
 714                                         $html[] = $this->listoutput
 715                                                 ? $line
 716                                                 : "<li>{$line}</li>\n";
 717                                 }
 718                         }
 719
 720                         # Flush the final result
 721                         if ( $this->tryLastResult() ) {
 722                                 $row = null;
 723                                 $line = $this->formatResult( $skin, $row );
 724                                 if ( $line ) {
 725                                         $html[] = $this->listoutput
 726                                                 ? $line
 727                                                 : "<li>{$line}</li>\n";
 728                                 }
 729                         }
 730
 731                         if ( !$this->listoutput ) {
 732                                 $html[] = $this->closeList();
 733                         }
 734
 735                         $html = $this->listoutput
 736                                 ? MediaWikiServices::getInstance()->getContentLanguage()->listToText( $html )
 737                                 : implode( '', $html );
 738
 739                         $out->addHTML( $html );
 740                 }
 741         }
 742
 743         /**
 744          * @param int $offset
 745          * @return string
 746          */
 747         function openList( $offset ) {
 748                 return "\n<ol start='" . ( $offset + 1 ) . "' class='special'>\n";
 749         }
 750
 751         /**
 752          * @return string
 753          */
 754         function closeList() {
 755                 return "</ol>\n";
 756         }
 757
 758         /**
 759          * Do any necessary preprocessing of the result object.
 760          * @param IDatabase $db
 761          * @param IResultWrapper $res
 762          */
 763         function preprocessResults( $db, $res ) {
 764         }
 765
 766         /**
 767          * Creates a new LinkBatch object, adds all pages from the passed ResultWrapper (MUST include
 768          * title and optional the namespace field) and executes the batch. This operation will pre-cache
 769          * LinkCache information like page existence and information for stub color and redirect hints.
 770          *
 771          * @param IResultWrapper $res The ResultWrapper object to process. Needs to include the title
 772          *  field and namespace field, if the $ns parameter isn't set.
 773          * @param null $ns Use this namespace for the given titles in the ResultWrapper object,
 774          *  instead of the namespace value of $res.
 775          */
 776         protected function executeLBFromResultWrapper( IResultWrapper $res, $ns = null ) {
 777                 if ( !$res->numRows() ) {
 778                         return;
 779                 }
 780
 781                 $batch = new LinkBatch;
 782                 foreach ( $res as $row ) {
 783                         $batch->add( $ns ?? $row->namespace, $row->title );
 784                 }
 785                 $batch->execute();
 786
 787                 $res->seek( 0 );
 788         }
 789 }