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 Wikimedia\Rdbms\ResultWrapper;
  25 use Wikimedia\Rdbms\IDatabase;
  26 use Wikimedia\Rdbms\DBError;
  27
  28 /**
  29  * This is a class for doing query pages; since they're almost all the same,
  30  * we factor out some of the functionality into a superclass, and let
  31  * subclasses derive from it.
  32  * @ingroup SpecialPage
  33  */
  34 abstract class QueryPage extends SpecialPage {
  35         /** @var bool Whether or not we want plain listoutput rather than an ordered list */
  36         protected $listoutput = false;
  37
  38         /** @var int The offset and limit in use, as passed to the query() function */
  39         protected $offset = 0;
  40
  41         /** @var int */
  42         protected $limit = 0;
  43
  44         /**
  45          * The number of rows returned by the query. Reading this variable
  46          * only makes sense in functions that are run after the query has been
  47          * done, such as preprocessResults() and formatRow().
  48          */
  49         protected $numRows;
  50
  51         protected $cachedTimestamp = null;
  52
  53         /**
  54          * Whether to show prev/next links
  55          */
  56         protected $shownavigation = true;
  57
  58         /**
  59          * Get a list of query page classes and their associated special pages,
  60          * for periodic updates.
  61          *
  62          * DO NOT CHANGE THIS LIST without testing that
  63          * maintenance/updateSpecialPages.php still works.
  64          * @return array
  65          */
  66         public static function getPages() {
  67                 static $qp = null;
  68
  69                 if ( $qp === null ) {
  70                         // QueryPage subclass, Special page name
  71                         $qp = [
  72                                 [ 'AncientPagesPage', 'Ancientpages' ],
  73                                 [ 'BrokenRedirectsPage', 'BrokenRedirects' ],
  74                                 [ 'DeadendPagesPage', 'Deadendpages' ],
  75                                 [ 'DoubleRedirectsPage', 'DoubleRedirects' ],
  76                                 [ 'FileDuplicateSearchPage', 'FileDuplicateSearch' ],
  77                                 [ 'ListDuplicatedFilesPage', 'ListDuplicatedFiles' ],
  78                                 [ 'LinkSearchPage', 'LinkSearch' ],
  79                                 [ 'ListredirectsPage', 'Listredirects' ],
  80                                 [ 'LonelyPagesPage', 'Lonelypages' ],
  81                                 [ 'LongPagesPage', 'Longpages' ],
  82                                 [ 'MediaStatisticsPage', 'MediaStatistics' ],
  83                                 [ 'MIMEsearchPage', 'MIMEsearch' ],
  84                                 [ 'MostcategoriesPage', 'Mostcategories' ],
  85                                 [ 'MostimagesPage', 'Mostimages' ],
  86                                 [ 'MostinterwikisPage', 'Mostinterwikis' ],
  87                                 [ 'MostlinkedCategoriesPage', 'Mostlinkedcategories' ],
  88                                 [ 'MostlinkedTemplatesPage', 'Mostlinkedtemplates' ],
  89                                 [ 'MostlinkedPage', 'Mostlinked' ],
  90                                 [ 'MostrevisionsPage', 'Mostrevisions' ],
  91                                 [ 'FewestrevisionsPage', 'Fewestrevisions' ],
  92                                 [ 'ShortPagesPage', 'Shortpages' ],
  93                                 [ 'UncategorizedCategoriesPage', 'Uncategorizedcategories' ],
  94                                 [ 'UncategorizedPagesPage', 'Uncategorizedpages' ],
  95                                 [ 'UncategorizedImagesPage', 'Uncategorizedimages' ],
  96                                 [ 'UncategorizedTemplatesPage', 'Uncategorizedtemplates' ],
  97                                 [ 'UnusedCategoriesPage', 'Unusedcategories' ],
  98                                 [ 'UnusedimagesPage', 'Unusedimages' ],
  99                                 [ 'WantedCategoriesPage', 'Wantedcategories' ],
 100                                 [ 'WantedFilesPage', 'Wantedfiles' ],
 101                                 [ 'WantedPagesPage', 'Wantedpages' ],
 102                                 [ 'WantedTemplatesPage', 'Wantedtemplates' ],
 103                                 [ 'UnwatchedpagesPage', 'Unwatchedpages' ],
 104                                 [ 'UnusedtemplatesPage', 'Unusedtemplates' ],
 105                                 [ 'WithoutInterwikiPage', 'Withoutinterwiki' ],
 106                         ];
 107                         Hooks::run( 'wgQueryPages', [ &$qp ] );
 108                 }
 109
 110                 return $qp;
 111         }
 112
 113         /**
 114          * A mutator for $this->listoutput;
 115          *
 116          * @param bool $bool
 117          */
 118         function setListoutput( $bool ) {
 119                 $this->listoutput = $bool;
 120         }
 121
 122         /**
 123          * Subclasses return an SQL query here, formatted as an array with the
 124          * following keys:
 125          *    tables => Table(s) for passing to Database::select()
 126          *    fields => Field(s) for passing to Database::select(), may be *
 127          *    conds => WHERE conditions
 128          *    options => options
 129          *    join_conds => JOIN conditions
 130          *
 131          * Note that the query itself should return the following three columns:
 132          * 'namespace', 'title', and 'value'. 'value' is used for sorting.
 133          *
 134          * These may be stored in the querycache table for expensive queries,
 135          * and that cached data will be returned sometimes, so the presence of
 136          * extra fields can't be relied upon. The cached 'value' column will be
 137          * an integer; non-numeric values are useful only for sorting the
 138          * initial query (except if they're timestamps, see usesTimestamps()).
 139          *
 140          * Don't include an ORDER or LIMIT clause, they will be added.
 141          *
 142          * If this function is not overridden or returns something other than
 143          * an array, getSQL() will be used instead. This is for backwards
 144          * compatibility only and is strongly deprecated.
 145          * @return array
 146          * @since 1.18
 147          */
 148         public function getQueryInfo() {
 149                 return null;
 150         }
 151
 152         /**
 153          * For back-compat, subclasses may return a raw SQL query here, as a string.
 154          * This is strongly deprecated; getQueryInfo() should be overridden instead.
 155          * @throws MWException
 156          * @return string
 157          */
 158         function getSQL() {
 159                 /* Implement getQueryInfo() instead */
 160                 throw new MWException( "Bug in a QueryPage: doesn't implement getQueryInfo() nor "
 161                         . "getQuery() properly" );
 162         }
 163
 164         /**
 165          * Subclasses return an array of fields to order by here. Don't append
 166          * DESC to the field names, that'll be done automatically if
 167          * sortDescending() returns true.
 168          * @return array
 169          * @since 1.18
 170          */
 171         function getOrderFields() {
 172                 return [ 'value' ];
 173         }
 174
 175         /**
 176          * Does this query return timestamps rather than integers in its
 177          * 'value' field? If true, this class will convert 'value' to a
 178          * UNIX timestamp for caching.
 179          * NOTE: formatRow() may get timestamps in TS_MW (mysql), TS_DB (pgsql)
 180          *       or TS_UNIX (querycache) format, so be sure to always run them
 181          *       through wfTimestamp()
 182          * @return bool
 183          * @since 1.18
 184          */
 185         public function usesTimestamps() {
 186                 return false;
 187         }
 188
 189         /**
 190          * Override to sort by increasing values
 191          *
 192          * @return bool
 193          */
 194         function sortDescending() {
 195                 return true;
 196         }
 197
 198         /**
 199          * Is this query expensive (for some definition of expensive)? Then we
 200          * don't let it run in miser mode. $wgDisableQueryPages causes all query
 201          * pages to be declared expensive. Some query pages are always expensive.
 202          *
 203          * @return bool
 204          */
 205         public function isExpensive() {
 206                 return $this->getConfig()->get( 'DisableQueryPages' );
 207         }
 208
 209         /**
 210          * Is the output of this query cacheable? Non-cacheable expensive pages
 211          * will be disabled in miser mode and will not have their results written
 212          * to the querycache table.
 213          * @return bool
 214          * @since 1.18
 215          */
 216         public function isCacheable() {
 217                 return true;
 218         }
 219
 220         /**
 221          * Whether or not the output of the page in question is retrieved from
 222          * the database cache.
 223          *
 224          * @return bool
 225          */
 226         public function isCached() {
 227                 return $this->isExpensive() && $this->getConfig()->get( 'MiserMode' );
 228         }
 229
 230         /**
 231          * Sometime we don't want to build rss / atom feeds.
 232          *
 233          * @return bool
 234          */
 235         function isSyndicated() {
 236                 return true;
 237         }
 238
 239         /**
 240          * Formats the results of the query for display. The skin is the current
 241          * skin; you can use it for making links. The result is a single row of
 242          * result data. You should be able to grab SQL results off of it.
 243          * If the function returns false, the line output will be skipped.
 244          * @param Skin $skin
 245          * @param object $result Result row
 246          * @return string|bool String or false to skip
 247          */
 248         abstract function formatResult( $skin, $result );
 249
 250         /**
 251          * The content returned by this function will be output before any result
 252          *
 253          * @return string
 254          */
 255         function getPageHeader() {
 256                 return '';
 257         }
 258
 259         /**
 260          * Outputs some kind of an informative message (via OutputPage) to let the
 261          * user know that the query returned nothing and thus there's nothing to
 262          * show.
 263          *
 264          * @since 1.26
 265          */
 266         protected function showEmptyText() {
 267                 $this->getOutput()->addWikiMsg( 'specialpage-empty' );
 268         }
 269
 270         /**
 271          * If using extra form wheely-dealies, return a set of parameters here
 272          * as an associative array. They will be encoded and added to the paging
 273          * links (prev/next/lengths).
 274          *
 275          * @return array
 276          */
 277         function linkParameters() {
 278                 return [];
 279         }
 280
 281         /**
 282          * Some special pages (for example SpecialListusers used to) might not return the
 283          * current object formatted, but return the previous one instead.
 284          * Setting this to return true will ensure formatResult() is called
 285          * one more time to make sure that the very last result is formatted
 286          * as well.
 287          *
 288          * @deprecated since 1.27
 289          *
 290          * @return bool
 291          */
 292         function tryLastResult() {
 293                 return false;
 294         }
 295
 296         /**
 297          * Clear the cache and save new results
 298          *
 299          * @param int|bool $limit Limit for SQL statement
 300          * @param bool $ignoreErrors Whether to ignore database errors
 301          * @throws DBError|Exception
 302          * @return bool|int
 303          */
 304         public function recache( $limit, $ignoreErrors = true ) {
 305                 if ( !$this->isCacheable() ) {
 306                         return 0;
 307                 }
 308
 309                 $fname = static::class . '::recache';
 310                 $dbw = wfGetDB( DB_MASTER );
 311                 if ( !$dbw ) {
 312                         return false;
 313                 }
 314
 315                 try {
 316                         # Do query
 317                         $res = $this->reallyDoQuery( $limit, false );
 318                         $num = false;
 319                         if ( $res ) {
 320                                 $num = $res->numRows();
 321                                 # Fetch results
 322                                 $vals = [];
 323                                 foreach ( $res as $row ) {
 324                                         if ( isset( $row->value ) ) {
 325                                                 if ( $this->usesTimestamps() ) {
 326                                                         $value = wfTimestamp( TS_UNIX,
 327                                                                 $row->value );
 328                                                 } else {
 329                                                         $value = intval( $row->value ); // T16414
 330                                                 }
 331                                         } else {
 332                                                 $value = 0;
 333                                         }
 334
 335                                         $vals[] = [
 336                                                 'qc_type' => $this->getName(),
 337                                                 'qc_namespace' => $row->namespace,
 338                                                 'qc_title' => $row->title,
 339                                                 'qc_value' => $value
 340                                         ];
 341                                 }
 342
 343                                 $dbw->doAtomicSection(
 344                                         __METHOD__,
 345                                         function ( IDatabase $dbw, $fname ) use ( $vals ) {
 346                                                 # Clear out any old cached data
 347                                                 $dbw->delete( 'querycache',
 348                                                         [ 'qc_type' => $this->getName() ],
 349                                                         $fname
 350                                                 );
 351                                                 # Save results into the querycache table on the master
 352                                                 if ( count( $vals ) ) {
 353                                                         $dbw->insert( 'querycache', $vals, $fname );
 354                                                 }
 355                                                 # Update the querycache_info record for the page
 356                                                 $dbw->delete( 'querycache_info',
 357                                                         [ 'qci_type' => $this->getName() ],
 358                                                         $fname
 359                                                 );
 360                                                 $dbw->insert( 'querycache_info',
 361                                                         [ 'qci_type' => $this->getName(),
 362                                                                 'qci_timestamp' => $dbw->timestamp() ],
 363                                                         $fname
 364                                                 );
 365                                         }
 366                                 );
 367                         }
 368                 } catch ( DBError $e ) {
 369                         if ( !$ignoreErrors ) {
 370                                 throw $e; // report query error
 371                         }
 372                         $num = false; // set result to false to indicate error
 373                 }
 374
 375                 return $num;
 376         }
 377
 378         /**
 379          * Get a DB connection to be used for slow recache queries
 380          * @return IDatabase
 381          */
 382         function getRecacheDB() {
 383                 return wfGetDB( DB_REPLICA, [ $this->getName(), 'QueryPage::recache', 'vslow' ] );
 384         }
 385
 386         /**
 387          * Run the query and return the result
 388          * @param int|bool $limit Numerical limit or false for no limit
 389          * @param int|bool $offset Numerical offset or false for no offset
 390          * @return ResultWrapper
 391          * @since 1.18
 392          */
 393         public function reallyDoQuery( $limit, $offset = false ) {
 394                 $fname = static::class . '::reallyDoQuery';
 395                 $dbr = $this->getRecacheDB();
 396                 $query = $this->getQueryInfo();
 397                 $order = $this->getOrderFields();
 398
 399                 if ( $this->sortDescending() ) {
 400                         foreach ( $order as &$field ) {
 401                                 $field .= ' DESC';
 402                         }
 403                 }
 404
 405                 if ( is_array( $query ) ) {
 406                         $tables = isset( $query['tables'] ) ? (array)$query['tables'] : [];
 407                         $fields = isset( $query['fields'] ) ? (array)$query['fields'] : [];
 408                         $conds = isset( $query['conds'] ) ? (array)$query['conds'] : [];
 409                         $options = isset( $query['options'] ) ? (array)$query['options'] : [];
 410                         $join_conds = isset( $query['join_conds'] ) ? (array)$query['join_conds'] : [];
 411
 412                         if ( $order ) {
 413                                 $options['ORDER BY'] = $order;
 414                         }
 415
 416                         if ( $limit !== false ) {
 417                                 $options['LIMIT'] = intval( $limit );
 418                         }
 419
 420                         if ( $offset !== false ) {
 421                                 $options['OFFSET'] = intval( $offset );
 422                         }
 423
 424                         $res = $dbr->select( $tables, $fields, $conds, $fname,
 425                                         $options, $join_conds
 426                         );
 427                 } else {
 428                         // Old-fashioned raw SQL style, deprecated
 429                         $sql = $this->getSQL();
 430                         $sql .= ' ORDER BY ' . implode( ', ', $order );
 431                         $sql = $dbr->limitResult( $sql, $limit, $offset );
 432                         $res = $dbr->query( $sql, $fname );
 433                 }
 434
 435                 return $res;
 436         }
 437
 438         /**
 439          * Somewhat deprecated, you probably want to be using execute()
 440          * @param int|bool $offset
 441          * @param int|bool $limit
 442          * @return ResultWrapper
 443          */
 444         public function doQuery( $offset = false, $limit = false ) {
 445                 if ( $this->isCached() && $this->isCacheable() ) {
 446                         return $this->fetchFromCache( $limit, $offset );
 447                 } else {
 448                         return $this->reallyDoQuery( $limit, $offset );
 449                 }
 450         }
 451
 452         /**
 453          * Fetch the query results from the query cache
 454          * @param int|bool $limit Numerical limit or false for no limit
 455          * @param int|bool $offset Numerical offset or false for no offset
 456          * @return ResultWrapper
 457          * @since 1.18
 458          */
 459         public function fetchFromCache( $limit, $offset = false ) {
 460                 $dbr = wfGetDB( DB_REPLICA );
 461                 $options = [];
 462
 463                 if ( $limit !== false ) {
 464                         $options['LIMIT'] = intval( $limit );
 465                 }
 466
 467                 if ( $offset !== false ) {
 468                         $options['OFFSET'] = intval( $offset );
 469                 }
 470
 471                 $order = $this->getCacheOrderFields();
 472                 if ( $this->sortDescending() ) {
 473                         foreach ( $order as &$field ) {
 474                                 $field .= " DESC";
 475                         }
 476                 }
 477                 if ( $order ) {
 478                         $options['ORDER BY'] = $order;
 479                 }
 480
 481                 return $dbr->select( 'querycache',
 482                                 [ 'qc_type',
 483                                 'namespace' => 'qc_namespace',
 484                                 'title' => 'qc_title',
 485                                 'value' => 'qc_value' ],
 486                                 [ 'qc_type' => $this->getName() ],
 487                                 __METHOD__,
 488                                 $options
 489                 );
 490         }
 491
 492         /**
 493          * Return the order fields for fetchFromCache. Default is to always use
 494          * "ORDER BY value" which was the default prior to this function.
 495          * @return array
 496          * @since 1.29
 497          */
 498         function getCacheOrderFields() {
 499                 return [ 'value' ];
 500         }
 501
 502         public function getCachedTimestamp() {
 503                 if ( is_null( $this->cachedTimestamp ) ) {
 504                         $dbr = wfGetDB( DB_REPLICA );
 505                         $fname = static::class . '::getCachedTimestamp';
 506                         $this->cachedTimestamp = $dbr->selectField( 'querycache_info', 'qci_timestamp',
 507                                 [ 'qci_type' => $this->getName() ], $fname );
 508                 }
 509                 return $this->cachedTimestamp;
 510         }
 511
 512         /**
 513          * Returns limit and offset, as returned by $this->getRequest()->getLimitOffset().
 514          * Subclasses may override this to further restrict or modify limit and offset.
 515          *
 516          * @note Restricts the offset parameter, as most query pages have inefficient paging
 517          *
 518          * Its generally expected that the returned limit will not be 0, and the returned
 519          * offset will be less than the max results.
 520          *
 521          * @since 1.26
 522          * @return int[] list( $limit, $offset )
 523          */
 524         protected function getLimitOffset() {
 525                 list( $limit, $offset ) = $this->getRequest()->getLimitOffset();
 526                 if ( $this->getConfig()->get( 'MiserMode' ) ) {
 527                         $maxResults = $this->getMaxResults();
 528                         // Can't display more than max results on a page
 529                         $limit = min( $limit, $maxResults );
 530                         // Can't skip over more than the end of $maxResults
 531                         $offset = min( $offset, $maxResults + 1 );
 532                 }
 533                 return [ $limit, $offset ];
 534         }
 535
 536         /**
 537          * What is limit to fetch from DB
 538          *
 539          * Used to make it appear the DB stores less results then it actually does
 540          * @param int $uiLimit Limit from UI
 541          * @param int $uiOffset Offset from UI
 542          * @return int Limit to use for DB (not including extra row to see if at end)
 543          */
 544         protected function getDBLimit( $uiLimit, $uiOffset ) {
 545                 $maxResults = $this->getMaxResults();
 546                 if ( $this->getConfig()->get( 'MiserMode' ) ) {
 547                         $limit = min( $uiLimit + 1, $maxResults - $uiOffset );
 548                         return max( $limit, 0 );
 549                 } else {
 550                         return $uiLimit + 1;
 551                 }
 552         }
 553
 554         /**
 555          * Get max number of results we can return in miser mode.
 556          *
 557          * Most QueryPage subclasses use inefficient paging, so limit the max amount we return
 558          * This matters for uncached query pages that might otherwise accept an offset of 3 million
 559          *
 560          * @since 1.27
 561          * @return int
 562          */
 563         protected function getMaxResults() {
 564                 // Max of 10000, unless we store more than 10000 in query cache.
 565                 return max( $this->getConfig()->get( 'QueryCacheLimit' ), 10000 );
 566         }
 567
 568         /**
 569          * This is the actual workhorse. It does everything needed to make a
 570          * real, honest-to-gosh query page.
 571          * @param string $par
 572          */
 573         public function execute( $par ) {
 574                 $user = $this->getUser();
 575                 if ( !$this->userCanExecute( $user ) ) {
 576                         $this->displayRestrictionError();
 577                         return;
 578                 }
 579
 580                 $this->setHeaders();
 581                 $this->outputHeader();
 582
 583                 $out = $this->getOutput();
 584
 585                 if ( $this->isCached() && !$this->isCacheable() ) {
 586                         $out->addWikiMsg( 'querypage-disabled' );
 587                         return;
 588                 }
 589
 590                 $out->setSyndicated( $this->isSyndicated() );
 591
 592                 if ( $this->limit == 0 && $this->offset == 0 ) {
 593                         list( $this->limit, $this->offset ) = $this->getLimitOffset();
 594                 }
 595                 $dbLimit = $this->getDBLimit( $this->limit, $this->offset );
 596                 // @todo Use doQuery()
 597                 if ( !$this->isCached() ) {
 598                         # select one extra row for navigation
 599                         $res = $this->reallyDoQuery( $dbLimit, $this->offset );
 600                 } else {
 601                         # Get the cached result, select one extra row for navigation
 602                         $res = $this->fetchFromCache( $dbLimit, $this->offset );
 603                         if ( !$this->listoutput ) {
 604                                 # Fetch the timestamp of this update
 605                                 $ts = $this->getCachedTimestamp();
 606                                 $lang = $this->getLanguage();
 607                                 $maxResults = $lang->formatNum( $this->getConfig()->get( 'QueryCacheLimit' ) );
 608
 609                                 if ( $ts ) {
 610                                         $updated = $lang->userTimeAndDate( $ts, $user );
 611                                         $updateddate = $lang->userDate( $ts, $user );
 612                                         $updatedtime = $lang->userTime( $ts, $user );
 613                                         $out->addMeta( 'Data-Cache-Time', $ts );
 614                                         $out->addJsConfigVars( 'dataCacheTime', $ts );
 615                                         $out->addWikiMsg( 'perfcachedts', $updated, $updateddate, $updatedtime, $maxResults );
 616                                 } else {
 617                                         $out->addWikiMsg( 'perfcached', $maxResults );
 618                                 }
 619
 620                                 # If updates on this page have been disabled, let the user know
 621                                 # that the data set won't be refreshed for now
 622                                 if ( is_array( $this->getConfig()->get( 'DisableQueryPageUpdate' ) )
 623                                         && in_array( $this->getName(), $this->getConfig()->get( 'DisableQueryPageUpdate' ) )
 624                                 ) {
 625                                         $out->wrapWikiMsg(
 626                                                 "<div class=\"mw-querypage-no-updates\">\n$1\n</div>",
 627                                                 'querypage-no-updates'
 628                                         );
 629                                 }
 630                         }
 631                 }
 632
 633                 $this->numRows = $res->numRows();
 634
 635                 $dbr = $this->getRecacheDB();
 636                 $this->preprocessResults( $dbr, $res );
 637
 638                 $out->addHTML( Xml::openElement( 'div', [ 'class' => 'mw-spcontent' ] ) );
 639
 640                 # Top header and navigation
 641                 if ( $this->shownavigation ) {
 642                         $out->addHTML( $this->getPageHeader() );
 643                         if ( $this->numRows > 0 ) {
 644                                 $out->addHTML( $this->msg( 'showingresultsinrange' )->numParams(
 645                                         min( $this->numRows, $this->limit ), # do not show the one extra row, if exist
 646                                         $this->offset + 1, ( min( $this->numRows, $this->limit ) + $this->offset ) )->parseAsBlock() );
 647                                 # Disable the "next" link when we reach the end
 648                                 $miserMaxResults = $this->getConfig()->get( 'MiserMode' )
 649                                         && ( $this->offset + $this->limit >= $this->getMaxResults() );
 650                                 $atEnd = ( $this->numRows <= $this->limit ) || $miserMaxResults;
 651                                 $paging = $this->getLanguage()->viewPrevNext( $this->getPageTitle( $par ), $this->offset,
 652                                         $this->limit, $this->linkParameters(), $atEnd );
 653                                 $out->addHTML( '<p>' . $paging . '</p>' );
 654                         } else {
 655                                 # No results to show, so don't bother with "showing X of Y" etc.
 656                                 # -- just let the user know and give up now
 657                                 $this->showEmptyText();
 658                                 $out->addHTML( Xml::closeElement( 'div' ) );
 659                                 return;
 660                         }
 661                 }
 662
 663                 # The actual results; specialist subclasses will want to handle this
 664                 # with more than a straight list, so we hand them the info, plus
 665                 # an OutputPage, and let them get on with it
 666                 $this->outputResults( $out,
 667                         $this->getSkin(),
 668                         $dbr, # Should use a ResultWrapper for this
 669                         $res,
 670                         min( $this->numRows, $this->limit ), # do not format the one extra row, if exist
 671                         $this->offset );
 672
 673                 # Repeat the paging links at the bottom
 674                 if ( $this->shownavigation ) {
 675                         $out->addHTML( '<p>' . $paging . '</p>' );
 676                 }
 677
 678                 $out->addHTML( Xml::closeElement( 'div' ) );
 679         }
 680
 681         /**
 682          * Format and output report results using the given information plus
 683          * OutputPage
 684          *
 685          * @param OutputPage $out OutputPage to print to
 686          * @param Skin $skin User skin to use
 687          * @param IDatabase $dbr Database (read) connection to use
 688          * @param ResultWrapper $res Result pointer
 689          * @param int $num Number of available result rows
 690          * @param int $offset Paging offset
 691          */
 692         protected function outputResults( $out, $skin, $dbr, $res, $num, $offset ) {
 693                 global $wgContLang;
 694
 695                 if ( $num > 0 ) {
 696                         $html = [];
 697                         if ( !$this->listoutput ) {
 698                                 $html[] = $this->openList( $offset );
 699                         }
 700
 701                         # $res might contain the whole 1,000 rows, so we read up to
 702                         # $num [should update this to use a Pager]
 703                         // @codingStandardsIgnoreStart Generic.CodeAnalysis.ForLoopWithTestFunctionCall.NotAllowed
 704                         for ( $i = 0; $i < $num && $row = $res->fetchObject(); $i++ ) {
 705                                 // @codingStandardsIgnoreEnd
 706                                 $line = $this->formatResult( $skin, $row );
 707                                 if ( $line ) {
 708                                         $html[] = $this->listoutput
 709                                                 ? $line
 710                                                 : "<li>{$line}</li>\n";
 711                                 }
 712                         }
 713
 714                         # Flush the final result
 715                         if ( $this->tryLastResult() ) {
 716                                 $row = null;
 717                                 $line = $this->formatResult( $skin, $row );
 718                                 if ( $line ) {
 719                                         $html[] = $this->listoutput
 720                                                 ? $line
 721                                                 : "<li>{$line}</li>\n";
 722                                 }
 723                         }
 724
 725                         if ( !$this->listoutput ) {
 726                                 $html[] = $this->closeList();
 727                         }
 728
 729                         $html = $this->listoutput
 730                                 ? $wgContLang->listToText( $html )
 731                                 : implode( '', $html );
 732
 733                         $out->addHTML( $html );
 734                 }
 735         }
 736
 737         /**
 738          * @param int $offset
 739          * @return string
 740          */
 741         function openList( $offset ) {
 742                 return "\n<ol start='" . ( $offset + 1 ) . "' class='special'>\n";
 743         }
 744
 745         /**
 746          * @return string
 747          */
 748         function closeList() {
 749                 return "</ol>\n";
 750         }
 751
 752         /**
 753          * Do any necessary preprocessing of the result object.
 754          * @param IDatabase $db
 755          * @param ResultWrapper $res
 756          */
 757         function preprocessResults( $db, $res ) {
 758         }
 759
 760         /**
 761          * Similar to above, but packaging in a syndicated feed instead of a web page
 762          * @param string $class
 763          * @param int $limit
 764          * @return bool
 765          */
 766         function doFeed( $class = '', $limit = 50 ) {
 767                 if ( !$this->getConfig()->get( 'Feed' ) ) {
 768                         $this->getOutput()->addWikiMsg( 'feed-unavailable' );
 769                         return false;
 770                 }
 771
 772                 $limit = min( $limit, $this->getConfig()->get( 'FeedLimit' ) );
 773
 774                 $feedClasses = $this->getConfig()->get( 'FeedClasses' );
 775                 if ( isset( $feedClasses[$class] ) ) {
 776                         /** @var RSSFeed|AtomFeed $feed */
 777                         $feed = new $feedClasses[$class](
 778                                 $this->feedTitle(),
 779                                 $this->feedDesc(),
 780                                 $this->feedUrl() );
 781                         $feed->outHeader();
 782
 783                         $res = $this->reallyDoQuery( $limit, 0 );
 784                         foreach ( $res as $obj ) {
 785                                 $item = $this->feedResult( $obj );
 786                                 if ( $item ) {
 787                                         $feed->outItem( $item );
 788                                 }
 789                         }
 790
 791                         $feed->outFooter();
 792                         return true;
 793                 } else {
 794                         return false;
 795                 }
 796         }
 797
 798         /**
 799          * Override for custom handling. If the titles/links are ok, just do
 800          * feedItemDesc()
 801          * @param object $row
 802          * @return FeedItem|null
 803          */
 804         function feedResult( $row ) {
 805                 if ( !isset( $row->title ) ) {
 806                         return null;
 807                 }
 808                 $title = Title::makeTitle( intval( $row->namespace ), $row->title );
 809                 if ( $title ) {
 810                         $date = isset( $row->timestamp ) ? $row->timestamp : '';
 811                         $comments = '';
 812                         if ( $title ) {
 813                                 $talkpage = $title->getTalkPage();
 814                                 $comments = $talkpage->getFullURL();
 815                         }
 816
 817                         return new FeedItem(
 818                                 $title->getPrefixedText(),
 819                                 $this->feedItemDesc( $row ),
 820                                 $title->getFullURL(),
 821                                 $date,
 822                                 $this->feedItemAuthor( $row ),
 823                                 $comments );
 824                 } else {
 825                         return null;
 826                 }
 827         }
 828
 829         function feedItemDesc( $row ) {
 830                 return isset( $row->comment ) ? htmlspecialchars( $row->comment ) : '';
 831         }
 832
 833         function feedItemAuthor( $row ) {
 834                 return isset( $row->user_text ) ? $row->user_text : '';
 835         }
 836
 837         function feedTitle() {
 838                 $desc = $this->getDescription();
 839                 $code = $this->getConfig()->get( 'LanguageCode' );
 840                 $sitename = $this->getConfig()->get( 'Sitename' );
 841                 return "$sitename - $desc [$code]";
 842         }
 843
 844         function feedDesc() {
 845                 return $this->msg( 'tagline' )->text();
 846         }
 847
 848         function feedUrl() {
 849                 return $this->getPageTitle()->getFullURL();
 850         }
 851
 852         /**
 853          * Creates a new LinkBatch object, adds all pages from the passed ResultWrapper (MUST include
 854          * title and optional the namespace field) and executes the batch. This operation will pre-cache
 855          * LinkCache information like page existence and information for stub color and redirect hints.
 856          *
 857          * @param ResultWrapper $res The ResultWrapper object to process. Needs to include the title
 858          *  field and namespace field, if the $ns parameter isn't set.
 859          * @param null $ns Use this namespace for the given titles in the ResultWrapper object,
 860          *  instead of the namespace value of $res.
 861          */
 862         protected function executeLBFromResultWrapper( ResultWrapper $res, $ns = null ) {
 863                 if ( !$res->numRows() ) {
 864                         return;
 865                 }
 866
 867                 $batch = new LinkBatch;
 868                 foreach ( $res as $row ) {
 869                         $batch->add( $ns !== null ? $ns : $row->namespace, $row->title );
 870                 }
 871                 $batch->execute();
 872
 873                 $res->seek( 0 );
 874         }
 875 }