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\Linker\LinkTarget;
  25 use MediaWiki\MediaWikiServices;
  26 use Wikimedia\Rdbms\IResultWrapper;
  27 use Wikimedia\Rdbms\IDatabase;
  28 use Wikimedia\Rdbms\DBError;
  29
  30 /**
  31  * This is a class for doing query pages; since they're almost all the same,
  32  * we factor out some of the functionality into a superclass, and let
  33  * subclasses derive from it.
  34  * @ingroup SpecialPage
  35  */
  36 abstract class QueryPage extends SpecialPage {
  37         /** @var bool Whether or not we want plain listoutput rather than an ordered list */
  38         protected $listoutput = false;
  39
  40         /** @var int The offset and limit in use, as passed to the query() function */
  41         protected $offset = 0;
  42
  43         /** @var int */
  44         protected $limit = 0;
  45
  46         /**
  47          * The number of rows returned by the query. Reading this variable
  48          * only makes sense in functions that are run after the query has been
  49          * done, such as preprocessResults() and formatRow().
  50          *
  51          * @var int
  52          */
  53         protected $numRows;
  54
  55         /**
  56          * @var string|null
  57          */
  58         protected $cachedTimestamp = null;
  59
  60         /**
  61          * @var bool Whether to show prev/next links
  62          */
  63         protected $shownavigation = true;
  64
  65         /**
  66          * Get a list of query page classes and their associated special pages,
  67          * for periodic updates.
  68          *
  69          * DO NOT CHANGE THIS LIST without testing that
  70          * maintenance/updateSpecialPages.php still works.
  71          *
  72          * @return string[][]
  73          */
  74         public static function getPages() {
  75                 static $qp = null;
  76
  77                 if ( $qp === null ) {
  78                         // QueryPage subclass, Special page name
  79                         $qp = [
  80                                 [ SpecialAncientPages::class, 'Ancientpages' ],
  81                                 [ SpecialBrokenRedirects::class, 'BrokenRedirects' ],
  82                                 [ SpecialDeadendPages::class, 'Deadendpages' ],
  83                                 [ SpecialDoubleRedirects::class, 'DoubleRedirects' ],
  84                                 [ SpecialFileDuplicateSearch::class, 'FileDuplicateSearch' ],
  85                                 [ SpecialListDuplicatedFiles::class, 'ListDuplicatedFiles' ],
  86                                 [ SpecialLinkSearch::class, 'LinkSearch' ],
  87                                 [ SpecialListRedirects::class, 'Listredirects' ],
  88                                 [ SpecialLonelyPages::class, 'Lonelypages' ],
  89                                 [ SpecialLongPages::class, 'Longpages' ],
  90                                 [ SpecialMediaStatistics::class, 'MediaStatistics' ],
  91                                 [ SpecialMIMESearch::class, 'MIMEsearch' ],
  92                                 [ SpecialMostCategories::class, 'Mostcategories' ],
  93                                 [ MostimagesPage::class, 'Mostimages' ],
  94                                 [ SpecialMostInterwikis::class, 'Mostinterwikis' ],
  95                                 [ SpecialMostLinkedCategories::class, 'Mostlinkedcategories' ],
  96                                 [ SpecialMostLinkedTemplates::class, 'Mostlinkedtemplates' ],
  97                                 [ SpecialMostLinked::class, 'Mostlinked' ],
  98                                 [ SpecialMostRevisions::class, 'Mostrevisions' ],
  99                                 [ SpecialFewestRevisions::class, 'Fewestrevisions' ],
 100                                 [ SpecialShortPages::class, 'Shortpages' ],
 101                                 [ SpecialUncategorizedCategories::class, 'Uncategorizedcategories' ],
 102                                 [ SpecialUncategorizedPages::class, 'Uncategorizedpages' ],
 103                                 [ SpecialUncategorizedImages::class, 'Uncategorizedimages' ],
 104                                 [ SpecialUncategorizedTemplates::class, 'Uncategorizedtemplates' ],
 105                                 [ SpecialUnusedCategories::class, 'Unusedcategories' ],
 106                                 [ SpecialUnusedImages::class, 'Unusedimages' ],
 107                                 [ SpecialWantedCategories::class, 'Wantedcategories' ],
 108                                 [ WantedFilesPage::class, 'Wantedfiles' ],
 109                                 [ WantedPagesPage::class, 'Wantedpages' ],
 110                                 [ SpecialWantedTemplates::class, 'Wantedtemplates' ],
 111                                 [ SpecialUnwatchedPages::class, 'Unwatchedpages' ],
 112                                 [ SpecialUnusedTemplates::class, 'Unusedtemplates' ],
 113                                 [ SpecialWithoutInterwiki::class, 'Withoutinterwiki' ],
 114                         ];
 115                         Hooks::run( 'wgQueryPages', [ &$qp ] );
 116                 }
 117
 118                 return $qp;
 119         }
 120
 121         /**
 122          * A mutator for $this->listoutput;
 123          *
 124          * @param bool $bool
 125          */
 126         function setListoutput( $bool ) {
 127                 $this->listoutput = $bool;
 128         }
 129
 130         /**
 131          * Subclasses return an SQL query here, formatted as an array with the
 132          * following keys:
 133          *    tables => Table(s) for passing to Database::select()
 134          *    fields => Field(s) for passing to Database::select(), may be *
 135          *    conds => WHERE conditions
 136          *    options => options
 137          *    join_conds => JOIN conditions
 138          *
 139          * Note that the query itself should return the following three columns:
 140          * 'namespace', 'title', and 'value'. 'value' is used for sorting.
 141          *
 142          * These may be stored in the querycache table for expensive queries,
 143          * and that cached data will be returned sometimes, so the presence of
 144          * extra fields can't be relied upon. The cached 'value' column will be
 145          * an integer; non-numeric values are useful only for sorting the
 146          * initial query (except if they're timestamps, see usesTimestamps()).
 147          *
 148          * Don't include an ORDER or LIMIT clause, they will be added.
 149          *
 150          * If this function is not overridden or returns something other than
 151          * an array, getSQL() will be used instead. This is for backwards
 152          * compatibility only and is strongly deprecated.
 153          * @return array
 154          * @since 1.18
 155          */
 156         public function getQueryInfo() {
 157                 return null;
 158         }
 159
 160         /**
 161          * For back-compat, subclasses may return a raw SQL query here, as a string.
 162          * This is strongly deprecated; getQueryInfo() should be overridden instead.
 163          * @throws MWException
 164          * @return string
 165          */
 166         function getSQL() {
 167                 /* Implement getQueryInfo() instead */
 168                 throw new MWException( "Bug in a QueryPage: doesn't implement getQueryInfo() nor "
 169                         . "getQuery() properly" );
 170         }
 171
 172         /**
 173          * Subclasses return an array of fields to order by here. Don't append
 174          * DESC to the field names, that'll be done automatically if
 175          * sortDescending() returns true.
 176          * @return string[]
 177          * @since 1.18
 178          */
 179         function getOrderFields() {
 180                 return [ 'value' ];
 181         }
 182
 183         /**
 184          * Does this query return timestamps rather than integers in its
 185          * 'value' field? If true, this class will convert 'value' to a
 186          * UNIX timestamp for caching.
 187          * NOTE: formatRow() may get timestamps in TS_MW (mysql), TS_DB (pgsql)
 188          *       or TS_UNIX (querycache) format, so be sure to always run them
 189          *       through wfTimestamp()
 190          * @return bool
 191          * @since 1.18
 192          */
 193         public function usesTimestamps() {
 194                 return false;
 195         }
 196
 197         /**
 198          * Override to sort by increasing values
 199          *
 200          * @return bool
 201          */
 202         function sortDescending() {
 203                 return true;
 204         }
 205
 206         /**
 207          * Is this query expensive (for some definition of expensive)? Then we
 208          * don't let it run in miser mode. $wgDisableQueryPages causes all query
 209          * pages to be declared expensive. Some query pages are always expensive.
 210          *
 211          * @return bool
 212          */
 213         public function isExpensive() {
 214                 return $this->getConfig()->get( 'DisableQueryPages' );
 215         }
 216
 217         /**
 218          * Is the output of this query cacheable? Non-cacheable expensive pages
 219          * will be disabled in miser mode and will not have their results written
 220          * to the querycache table.
 221          * @return bool
 222          * @since 1.18
 223          */
 224         public function isCacheable() {
 225                 return true;
 226         }
 227
 228         /**
 229          * Whether or not the output of the page in question is retrieved from
 230          * the database cache.
 231          *
 232          * @return bool
 233          */
 234         public function isCached() {
 235                 return $this->isExpensive() && $this->getConfig()->get( 'MiserMode' );
 236         }
 237
 238         /**
 239          * Sometime we don't want to build rss / atom feeds.
 240          *
 241          * @return bool
 242          */
 243         function isSyndicated() {
 244                 return true;
 245         }
 246
 247         /**
 248          * Formats the results of the query for display. The skin is the current
 249          * skin; you can use it for making links. The result is a single row of
 250          * result data. You should be able to grab SQL results off of it.
 251          * If the function returns false, the line output will be skipped.
 252          * @param Skin $skin
 253          * @param object $result Result row
 254          * @return string|bool String or false to skip
 255          */
 256         abstract function formatResult( $skin, $result );
 257
 258         /**
 259          * The content returned by this function will be output before any result
 260          *
 261          * @return string
 262          */
 263         function getPageHeader() {
 264                 return '';
 265         }
 266
 267         /**
 268          * Outputs some kind of an informative message (via OutputPage) to let the
 269          * user know that the query returned nothing and thus there's nothing to
 270          * show.
 271          *
 272          * @since 1.26
 273          */
 274         protected function showEmptyText() {
 275                 $this->getOutput()->addWikiMsg( 'specialpage-empty' );
 276         }
 277
 278         /**
 279          * If using extra form wheely-dealies, return a set of parameters here
 280          * as an associative array. They will be encoded and added to the paging
 281          * links (prev/next/lengths).
 282          *
 283          * @return array
 284          */
 285         function linkParameters() {
 286                 return [];
 287         }
 288
 289         /**
 290          * Clear the cache and save new results
 291          *
 292          * @param int|bool $limit Limit for SQL statement
 293          * @param bool $ignoreErrors Whether to ignore database errors
 294          * @throws DBError|Exception
 295          * @return bool|int
 296          */
 297         public function recache( $limit, $ignoreErrors = true ) {
 298                 if ( !$this->isCacheable() ) {
 299                         return 0;
 300                 }
 301
 302                 $fname = static::class . '::recache';
 303                 $dbw = wfGetDB( DB_MASTER );
 304                 if ( !$dbw ) {
 305                         return false;
 306                 }
 307
 308                 try {
 309                         # Do query
 310                         $res = $this->reallyDoQuery( $limit, false );
 311                         $num = false;
 312                         if ( $res ) {
 313                                 $num = $res->numRows();
 314                                 # Fetch results
 315                                 $vals = [];
 316                                 foreach ( $res as $i => $row ) {
 317                                         if ( isset( $row->value ) ) {
 318                                                 if ( $this->usesTimestamps() ) {
 319                                                         $value = wfTimestamp( TS_UNIX,
 320                                                                 $row->value );
 321                                                 } else {
 322                                                         $value = intval( $row->value ); // T16414
 323                                                 }
 324                                         } else {
 325                                                 $value = $i;
 326                                         }
 327
 328                                         $vals[] = [
 329                                                 'qc_type' => $this->getName(),
 330                                                 'qc_namespace' => $row->namespace,
 331                                                 'qc_title' => $row->title,
 332                                                 'qc_value' => $value
 333                                         ];
 334                                 }
 335
 336                                 $dbw->doAtomicSection(
 337                                         __METHOD__,
 338                                         function ( IDatabase $dbw, $fname ) use ( $vals ) {
 339                                                 # Clear out any old cached data
 340                                                 $dbw->delete( 'querycache',
 341                                                         [ 'qc_type' => $this->getName() ],
 342                                                         $fname
 343                                                 );
 344                                                 # Save results into the querycache table on the master
 345                                                 if ( count( $vals ) ) {
 346                                                         $dbw->insert( 'querycache', $vals, $fname );
 347                                                 }
 348                                                 # Update the querycache_info record for the page
 349                                                 $dbw->delete( 'querycache_info',
 350                                                         [ 'qci_type' => $this->getName() ],
 351                                                         $fname
 352                                                 );
 353                                                 $dbw->insert( 'querycache_info',
 354                                                         [ 'qci_type' => $this->getName(),
 355                                                                 'qci_timestamp' => $dbw->timestamp() ],
 356                                                         $fname
 357                                                 );
 358                                         }
 359                                 );
 360                         }
 361                 } catch ( DBError $e ) {
 362                         if ( !$ignoreErrors ) {
 363                                 throw $e; // report query error
 364                         }
 365                         $num = false; // set result to false to indicate error
 366                 }
 367
 368                 return $num;
 369         }
 370
 371         /**
 372          * Get a DB connection to be used for slow recache queries
 373          * @return IDatabase
 374          */
 375         function getRecacheDB() {
 376                 return wfGetDB( DB_REPLICA, [ $this->getName(), 'QueryPage::recache', 'vslow' ] );
 377         }
 378
 379         /**
 380          * Remove a cached result.
 381          * Useful for interactive backlogs where the user can fix problems in-place.
 382          * @param LinkTarget $title The page to remove.
 383          * @since 1.34
 384          */
 385         public function delete( LinkTarget $title ) {
 386                 if ( $this->isCached() ) {
 387                         $dbw = wfGetDB( DB_MASTER );
 388                         $dbw->delete( 'querycache', [
 389                                 'qc_type' => $this->getName(),
 390                                 'qc_namespace' => $title->getNamespace(),
 391                                 'qc_title' => $title->getDBkey(),
 392                         ], __METHOD__ );
 393                 }
 394         }
 395
 396         /**
 397          * Run the query and return the result
 398          * @param int|bool $limit Numerical limit or false for no limit
 399          * @param int|bool $offset Numerical offset or false for no offset
 400          * @return IResultWrapper
 401          * @since 1.18
 402          */
 403         public function reallyDoQuery( $limit, $offset = false ) {
 404                 $fname = static::class . '::reallyDoQuery';
 405                 $dbr = $this->getRecacheDB();
 406                 $query = $this->getQueryInfo();
 407                 $order = $this->getOrderFields();
 408
 409                 if ( $this->sortDescending() ) {
 410                         foreach ( $order as &$field ) {
 411                                 $field .= ' DESC';
 412                         }
 413                 }
 414
 415                 if ( is_array( $query ) ) {
 416                         $tables = isset( $query['tables'] ) ? (array)$query['tables'] : [];
 417                         $fields = isset( $query['fields'] ) ? (array)$query['fields'] : [];
 418                         $conds = isset( $query['conds'] ) ? (array)$query['conds'] : [];
 419                         $options = isset( $query['options'] ) ? (array)$query['options'] : [];
 420                         $join_conds = isset( $query['join_conds'] ) ? (array)$query['join_conds'] : [];
 421
 422                         if ( $order ) {
 423                                 $options['ORDER BY'] = $order;
 424                         }
 425
 426                         if ( $limit !== false ) {
 427                                 $options['LIMIT'] = intval( $limit );
 428                         }
 429
 430                         if ( $offset !== false ) {
 431                                 $options['OFFSET'] = intval( $offset );
 432                         }
 433
 434                         $res = $dbr->select( $tables, $fields, $conds, $fname,
 435                                         $options, $join_conds
 436                         );
 437                 } else {
 438                         // Old-fashioned raw SQL style, deprecated
 439                         $sql = $this->getSQL();
 440                         $sql .= ' ORDER BY ' . implode( ', ', $order );
 441                         $sql = $dbr->limitResult( $sql, $limit, $offset );
 442                         $res = $dbr->query( $sql, $fname );
 443                 }
 444
 445                 return $res;
 446         }
 447
 448         /**
 449          * Somewhat deprecated, you probably want to be using execute()
 450          * @param int|bool $offset
 451          * @param int|bool $limit
 452          * @return IResultWrapper
 453          */
 454         public function doQuery( $offset = false, $limit = false ) {
 455                 if ( $this->isCached() && $this->isCacheable() ) {
 456                         return $this->fetchFromCache( $limit, $offset );
 457                 } else {
 458                         return $this->reallyDoQuery( $limit, $offset );
 459                 }
 460         }
 461
 462         /**
 463          * Fetch the query results from the query cache
 464          * @param int|bool $limit Numerical limit or false for no limit
 465          * @param int|bool $offset Numerical offset or false for no offset
 466          * @return IResultWrapper
 467          * @since 1.18
 468          */
 469         public function fetchFromCache( $limit, $offset = false ) {
 470                 $dbr = wfGetDB( DB_REPLICA );
 471                 $options = [];
 472
 473                 if ( $limit !== false ) {
 474                         $options['LIMIT'] = intval( $limit );
 475                 }
 476
 477                 if ( $offset !== false ) {
 478                         $options['OFFSET'] = intval( $offset );
 479                 }
 480
 481                 $order = $this->getCacheOrderFields();
 482                 if ( $this->sortDescending() ) {
 483                         foreach ( $order as &$field ) {
 484                                 $field .= " DESC";
 485                         }
 486                 }
 487                 if ( $order ) {
 488                         $options['ORDER BY'] = $order;
 489                 }
 490
 491                 return $dbr->select( 'querycache',
 492                                 [ 'qc_type',
 493                                 'namespace' => 'qc_namespace',
 494                                 'title' => 'qc_title',
 495                                 'value' => 'qc_value' ],
 496                                 [ 'qc_type' => $this->getName() ],
 497                                 __METHOD__,
 498                                 $options
 499                 );
 500         }
 501
 502         /**
 503          * Return the order fields for fetchFromCache. Default is to always use
 504          * "ORDER BY value" which was the default prior to this function.
 505          * @return array
 506          * @since 1.29
 507          */
 508         function getCacheOrderFields() {
 509                 return [ 'value' ];
 510         }
 511
 512         /**
 513          * @return string
 514          */
 515         public function getCachedTimestamp() {
 516                 if ( is_null( $this->cachedTimestamp ) ) {
 517                         $dbr = wfGetDB( DB_REPLICA );
 518                         $fname = static::class . '::getCachedTimestamp';
 519                         $this->cachedTimestamp = $dbr->selectField( 'querycache_info', 'qci_timestamp',
 520                                 [ 'qci_type' => $this->getName() ], $fname );
 521                 }
 522                 return $this->cachedTimestamp;
 523         }
 524
 525         /**
 526          * Returns limit and offset, as returned by $this->getRequest()->getLimitOffset().
 527          * Subclasses may override this to further restrict or modify limit and offset.
 528          *
 529          * @note Restricts the offset parameter, as most query pages have inefficient paging
 530          *
 531          * Its generally expected that the returned limit will not be 0, and the returned
 532          * offset will be less than the max results.
 533          *
 534          * @since 1.26
 535          * @return int[] list( $limit, $offset )
 536          */
 537         protected function getLimitOffset() {
 538                 list( $limit, $offset ) = $this->getRequest()->getLimitOffset();
 539                 if ( $this->getConfig()->get( 'MiserMode' ) ) {
 540                         $maxResults = $this->getMaxResults();
 541                         // Can't display more than max results on a page
 542                         $limit = min( $limit, $maxResults );
 543                         // Can't skip over more than the end of $maxResults
 544                         $offset = min( $offset, $maxResults + 1 );
 545                 }
 546                 return [ $limit, $offset ];
 547         }
 548
 549         /**
 550          * What is limit to fetch from DB
 551          *
 552          * Used to make it appear the DB stores less results then it actually does
 553          * @param int $uiLimit Limit from UI
 554          * @param int $uiOffset Offset from UI
 555          * @return int Limit to use for DB (not including extra row to see if at end)
 556          */
 557         protected function getDBLimit( $uiLimit, $uiOffset ) {
 558                 $maxResults = $this->getMaxResults();
 559                 if ( $this->getConfig()->get( 'MiserMode' ) ) {
 560                         $limit = min( $uiLimit + 1, $maxResults - $uiOffset );
 561                         return max( $limit, 0 );
 562                 } else {
 563                         return $uiLimit + 1;
 564                 }
 565         }
 566
 567         /**
 568          * Get max number of results we can return in miser mode.
 569          *
 570          * Most QueryPage subclasses use inefficient paging, so limit the max amount we return
 571          * This matters for uncached query pages that might otherwise accept an offset of 3 million
 572          *
 573          * @since 1.27
 574          * @return int
 575          */
 576         protected function getMaxResults() {
 577                 // Max of 10000, unless we store more than 10000 in query cache.
 578                 return max( $this->getConfig()->get( 'QueryCacheLimit' ), 10000 );
 579         }
 580
 581         /**
 582          * This is the actual workhorse. It does everything needed to make a
 583          * real, honest-to-gosh query page.
 584          * @param string|null $par
 585          */
 586         public function execute( $par ) {
 587                 $user = $this->getUser();
 588                 if ( !$this->userCanExecute( $user ) ) {
 589                         $this->displayRestrictionError();
 590                         return;
 591                 }
 592
 593                 $this->setHeaders();
 594                 $this->outputHeader();
 595
 596                 $out = $this->getOutput();
 597
 598                 if ( $this->isCached() && !$this->isCacheable() ) {
 599                         $out->addWikiMsg( 'querypage-disabled' );
 600                         return;
 601                 }
 602
 603                 $out->setSyndicated( $this->isSyndicated() );
 604
 605                 if ( $this->limit == 0 && $this->offset == 0 ) {
 606                         list( $this->limit, $this->offset ) = $this->getLimitOffset();
 607                 }
 608                 $dbLimit = $this->getDBLimit( $this->limit, $this->offset );
 609                 // @todo Use doQuery()
 610                 if ( !$this->isCached() ) {
 611                         # select one extra row for navigation
 612                         $res = $this->reallyDoQuery( $dbLimit, $this->offset );
 613                 } else {
 614                         # Get the cached result, select one extra row for navigation
 615                         $res = $this->fetchFromCache( $dbLimit, $this->offset );
 616                         if ( !$this->listoutput ) {
 617                                 # Fetch the timestamp of this update
 618                                 $ts = $this->getCachedTimestamp();
 619                                 $lang = $this->getLanguage();
 620                                 $maxResults = $lang->formatNum( $this->getConfig()->get( 'QueryCacheLimit' ) );
 621
 622                                 if ( $ts ) {
 623                                         $updated = $lang->userTimeAndDate( $ts, $user );
 624                                         $updateddate = $lang->userDate( $ts, $user );
 625                                         $updatedtime = $lang->userTime( $ts, $user );
 626                                         $out->addMeta( 'Data-Cache-Time', $ts );
 627                                         $out->addJsConfigVars( 'dataCacheTime', $ts );
 628                                         $out->addWikiMsg( 'perfcachedts', $updated, $updateddate, $updatedtime, $maxResults );
 629                                 } else {
 630                                         $out->addWikiMsg( 'perfcached', $maxResults );
 631                                 }
 632
 633                                 # If updates on this page have been disabled, let the user know
 634                                 # that the data set won't be refreshed for now
 635                                 if ( is_array( $this->getConfig()->get( 'DisableQueryPageUpdate' ) )
 636                                         && in_array( $this->getName(), $this->getConfig()->get( 'DisableQueryPageUpdate' ) )
 637                                 ) {
 638                                         $out->wrapWikiMsg(
 639                                                 "<div class=\"mw-querypage-no-updates\">\n$1\n</div>",
 640                                                 'querypage-no-updates'
 641                                         );
 642                                 }
 643                         }
 644                 }
 645
 646                 $this->numRows = $res->numRows();
 647
 648                 $dbr = $this->getRecacheDB();
 649                 $this->preprocessResults( $dbr, $res );
 650
 651                 $out->addHTML( Xml::openElement( 'div', [ 'class' => 'mw-spcontent' ] ) );
 652
 653                 # Top header and navigation
 654                 if ( $this->shownavigation ) {
 655                         $out->addHTML( $this->getPageHeader() );
 656                         if ( $this->numRows > 0 ) {
 657                                 $out->addHTML( $this->msg( 'showingresultsinrange' )->numParams(
 658                                         min( $this->numRows, $this->limit ), # do not show the one extra row, if exist
 659                                         $this->offset + 1, ( min( $this->numRows, $this->limit ) + $this->offset ) )->parseAsBlock() );
 660                                 # Disable the "next" link when we reach the end
 661                                 $miserMaxResults = $this->getConfig()->get( 'MiserMode' )
 662                                         && ( $this->offset + $this->limit >= $this->getMaxResults() );
 663                                 $atEnd = ( $this->numRows <= $this->limit ) || $miserMaxResults;
 664                                 $paging = $this->buildPrevNextNavigation( $this->offset,
 665                                         $this->limit, $this->linkParameters(), $atEnd, $par );
 666                                 $out->addHTML( '<p>' . $paging . '</p>' );
 667                         } else {
 668                                 # No results to show, so don't bother with "showing X of Y" etc.
 669                                 # -- just let the user know and give up now
 670                                 $this->showEmptyText();
 671                                 $out->addHTML( Xml::closeElement( 'div' ) );
 672                                 return;
 673                         }
 674                 }
 675
 676                 # The actual results; specialist subclasses will want to handle this
 677                 # with more than a straight list, so we hand them the info, plus
 678                 # an OutputPage, and let them get on with it
 679                 $this->outputResults( $out,
 680                         $this->getSkin(),
 681                         $dbr, # Should use IResultWrapper for this
 682                         $res,
 683                         min( $this->numRows, $this->limit ), # do not format the one extra row, if exist
 684                         $this->offset );
 685
 686                 # Repeat the paging links at the bottom
 687                 if ( $this->shownavigation ) {
 688                         $out->addHTML( '<p>' . $paging . '</p>' );
 689                 }
 690
 691                 $out->addHTML( Xml::closeElement( 'div' ) );
 692         }
 693
 694         /**
 695          * Format and output report results using the given information plus
 696          * OutputPage
 697          *
 698          * @param OutputPage $out OutputPage to print to
 699          * @param Skin $skin User skin to use
 700          * @param IDatabase $dbr Database (read) connection to use
 701          * @param IResultWrapper $res Result pointer
 702          * @param int $num Number of available result rows
 703          * @param int $offset Paging offset
 704          */
 705         protected function outputResults( $out, $skin, $dbr, $res, $num, $offset ) {
 706                 if ( $num > 0 ) {
 707                         $html = [];
 708                         if ( !$this->listoutput ) {
 709                                 $html[] = $this->openList( $offset );
 710                         }
 711
 712                         # $res might contain the whole 1,000 rows, so we read up to
 713                         # $num [should update this to use a Pager]
 714                         for ( $i = 0; $i < $num && $row = $res->fetchObject(); $i++ ) {
 715                                 $line = $this->formatResult( $skin, $row );
 716                                 if ( $line ) {
 717                                         $html[] = $this->listoutput
 718                                                 ? $line
 719                                                 : "<li>{$line}</li>\n";
 720                                 }
 721                         }
 722
 723                         if ( !$this->listoutput ) {
 724                                 $html[] = $this->closeList();
 725                         }
 726
 727                         $html = $this->listoutput
 728                                 ? MediaWikiServices::getInstance()->getContentLanguage()->listToText( $html )
 729                                 : implode( '', $html );
 730
 731                         $out->addHTML( $html );
 732                 }
 733         }
 734
 735         /**
 736          * @param int $offset
 737          * @return string
 738          */
 739         function openList( $offset ) {
 740                 return "\n<ol start='" . ( $offset + 1 ) . "' class='special'>\n";
 741         }
 742
 743         /**
 744          * @return string
 745          */
 746         function closeList() {
 747                 return "</ol>\n";
 748         }
 749
 750         /**
 751          * Do any necessary preprocessing of the result object.
 752          * @param IDatabase $db
 753          * @param IResultWrapper $res
 754          */
 755         function preprocessResults( $db, $res ) {
 756         }
 757
 758         /**
 759          * Creates a new LinkBatch object, adds all pages from the passed result wrapper (MUST include
 760          * title and optional the namespace field) and executes the batch. This operation will pre-cache
 761          * LinkCache information like page existence and information for stub color and redirect hints.
 762          *
 763          * @param IResultWrapper $res The result wrapper to process. Needs to include the title
 764          *  field and namespace field, if the $ns parameter isn't set.
 765          * @param null $ns Use this namespace for the given titles in the result wrapper,
 766          *  instead of the namespace value of $res.
 767          */
 768         protected function executeLBFromResultWrapper( IResultWrapper $res, $ns = null ) {
 769                 if ( !$res->numRows() ) {
 770                         return;
 771                 }
 772
 773                 $batch = new LinkBatch;
 774                 foreach ( $res as $row ) {
 775                         $batch->add( $ns ?? $row->namespace, $row->title );
 776                 }
 777                 $batch->execute();
 778
 779                 $res->seek( 0 );
 780         }
 781 }