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