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          *  - batchSize,      Number of watchlist entries to remove at once.
  32          *  - userId,         The ID for the user whose watchlist is being cleared.
  33          *  - maxWatchlistId, The maximum wl_id at the time the job was first created,
  34          */
  35         public function __construct( Title $title = null, array $params ) {
  36                 if ( !array_key_exists( 'batchSize', $params ) ) {
  37                         $params['batchSize'] = 1000;
  38                 }
  39
  40                 parent::__construct(
  41                         'clearUserWatchlist',
  42                         SpecialPage::getTitleFor( 'EditWatchlist', 'clear' ),
  43                         $params
  44                 );
  45
  46                 $this->removeDuplicates = true;
  47         }
  48
  49         public function run() {
  50                 $userId = $this->params['userId'];
  51                 $maxWatchlistId = $this->params['maxWatchlistId'];
  52
  53                 $loadBalancer = MediaWikiServices::getInstance()->getDBLoadBalancer();
  54                 $dbw = $loadBalancer->getConnection( DB_MASTER );
  55                 $dbr = $loadBalancer->getConnection( DB_REPLICA, [ 'watchlist' ] );
  56
  57                 // Wait before lock to try to reduce time waiting in the lock.
  58                 if ( !$loadBalancer->safeWaitForMasterPos( $dbr ) ) {
  59                         $this->setLastError( 'Timed out while waiting for slave to catch up before lock' );
  60                         return false;
  61                 }
  62
  63                 // Use a named lock so that jobs for this user see each others' changes
  64                 $lockKey = "ClearUserWatchlistJob:$userId";
  65                 $scopedLock = $dbw->getScopedLockAndFlush( $lockKey, __METHOD__, 10 );
  66                 if ( !$scopedLock ) {
  67                         $this->setLastError( "Could not acquire lock '$lockKey'" );
  68                         return false;
  69                 }
  70
  71                 if ( !$loadBalancer->safeWaitForMasterPos( $dbr ) ) {
  72                         $this->setLastError( 'Timed out while waiting for slave to catch up within lock' );
  73                         return false;
  74                 }
  75
  76                 // Clear any stale REPEATABLE-READ snapshot
  77                 $dbr->flushSnapshot( __METHOD__ );
  78
  79                 $watchlistIds = $dbr->selectFieldValues(
  80                         'watchlist',
  81                         'wl_id',
  82                         [
  83                                 'wl_user' => $userId,
  84                                 'wl_id <= ' . $maxWatchlistId
  85                         ],
  86                         __METHOD__,
  87                         [
  88                                 'ORDER BY' => 'wl_id ASC',
  89                                 'LIMIT' => $this->params['batchSize'],
  90                         ]
  91                 );
  92
  93                 if ( count( $watchlistIds ) == 0 ) {
  94                         return true;
  95                 }
  96
  97                 $dbw->delete( 'watchlist', [ 'wl_id' => $watchlistIds ], __METHOD__ );
  98
  99                 // Commit changes and remove lock before inserting next job.
 100                 $lbf = MediaWikiServices::getInstance()->getDBLoadBalancerFactory();
 101                 $lbf->commitMasterChanges( __METHOD__ );
 102                 unset( $scopedLock );
 103
 104                 if ( count( $watchlistIds ) == $this->params['batchSize'] ) {
 105                         JobQueueGroup::singleton()->push( new self( $this->getTitle(), $this->getParams() ) );
 106                 }
 107
 108                 return true;
 109         }
 110
 111         public function getDeduplicationInfo() {
 112                 $info = parent::getDeduplicationInfo();
 113                 // This job never has a namespace or title so we can't use it for deduplication
 114                 unset( $info['namespace'] );
 115                 unset( $info['title'] );
 116                 return $info;
 117         }
 118
 119 }