includes/jobqueue/jobs/ClearUserWatchlistJob.php

   1 <?php
   2
   3 use MediaWiki\MediaWikiServices;
   4
   5 /**
   6  * Job to clear a users watchlist in batches.
   7  *
   8  * @author Addshore
   9  *
  10  * @ingroup JobQueue
  11  * @since 1.31
  12  */
  13 class ClearUserWatchlistJob extends Job {
  14
  15         /**
  16          * @param User $user User to clear the watchlist for.
  17          * @param int $maxWatchlistId The maximum wl_id at the time the job was first created.
  18          *
  19          * @return ClearUserWatchlistJob
  20          */
  21         public static function newForUser( User $user, $maxWatchlistId ) {
  22                 return new self(
  23                         null,
  24                         [ 'userId' => $user->getId(), 'maxWatchlistId' => $maxWatchlistId ]
  25                 );
  26         }
  27
  28         /**
  29          * @param Title|null $title Not used by this job.
  30          * @param array $params
  31          *  - userId,         The ID for the user whose watchlist is being cleared.
  32          *  - maxWatchlistId, The maximum wl_id at the time the job was first created,
  33          */
  34         public function __construct( Title $title = null, array $params ) {
  35                 parent::__construct(
  36                         'clearUserWatchlist',
  37                         SpecialPage::getTitleFor( 'EditWatchlist', 'clear' ),
  38                         $params
  39                 );
  40
  41                 $this->removeDuplicates = true;
  42         }
  43
  44         public function run() {
  45                 global $wgUpdateRowsPerQuery;
  46                 $userId = $this->params['userId'];
  47                 $maxWatchlistId = $this->params['maxWatchlistId'];
  48                 $batchSize = $wgUpdateRowsPerQuery;
  49
  50                 $loadBalancer = MediaWikiServices::getInstance()->getDBLoadBalancer();
  51                 $dbw = $loadBalancer->getConnection( DB_MASTER );
  52                 $dbr = $loadBalancer->getConnection( DB_REPLICA, [ 'watchlist' ] );
  53
  54                 // Wait before lock to try to reduce time waiting in the lock.
  55                 if ( !$loadBalancer->safeWaitForMasterPos( $dbr ) ) {
  56                         $this->setLastError( 'Timed out waiting for replica to catch up before lock' );
  57                         return false;
  58                 }
  59
  60                 // Use a named lock so that jobs for this user see each others' changes
  61                 $lockKey = "ClearUserWatchlistJob:$userId";
  62                 $scopedLock = $dbw->getScopedLockAndFlush( $lockKey, __METHOD__, 10 );
  63                 if ( !$scopedLock ) {
  64                         $this->setLastError( "Could not acquire lock '$lockKey'" );
  65                         return false;
  66                 }
  67
  68                 if ( !$loadBalancer->safeWaitForMasterPos( $dbr ) ) {
  69                         $this->setLastError( 'Timed out waiting for replica to catch up within lock' );
  70                         return false;
  71                 }
  72
  73                 // Clear any stale REPEATABLE-READ snapshot
  74                 $dbr->flushSnapshot( __METHOD__ );
  75
  76                 $watchlistIds = $dbr->selectFieldValues(
  77                         'watchlist',
  78                         'wl_id',
  79                         [
  80                                 'wl_user' => $userId,
  81                                 'wl_id <= ' . $maxWatchlistId
  82                         ],
  83                         __METHOD__,
  84                         [
  85                                 'ORDER BY' => 'wl_id ASC',
  86                                 'LIMIT' => $batchSize,
  87                         ]
  88                 );
  89
  90                 if ( count( $watchlistIds ) == 0 ) {
  91                         return true;
  92                 }
  93
  94                 $dbw->delete( 'watchlist', [ 'wl_id' => $watchlistIds ], __METHOD__ );
  95
  96                 // Commit changes and remove lock before inserting next job.
  97                 $lbf = MediaWikiServices::getInstance()->getDBLoadBalancerFactory();
  98                 $lbf->commitMasterChanges( __METHOD__ );
  99                 unset( $scopedLock );
 100
 101                 if ( count( $watchlistIds ) === (int)$batchSize ) {
 102                         // Until we get less results than the limit, recursively push
 103                         // the same job again.
 104                         JobQueueGroup::singleton()->push( new self( $this->getTitle(), $this->getParams() ) );
 105                 }
 106
 107                 return true;
 108         }
 109
 110         public function getDeduplicationInfo() {
 111                 $info = parent::getDeduplicationInfo();
 112                 // This job never has a namespace or title so we can't use it for deduplication
 113                 unset( $info['namespace'] );
 114                 unset( $info['title'] );
 115                 return $info;
 116         }
 117
 118 }