wikimedia/mediawiki-core

<?php

namespace MediaWiki\Watchlist;

use GenericParameterJob;
use Job;
use MediaWiki\MainConfigNames;
use MediaWiki\MediaWikiServices;
use MediaWiki\User\UserIdentity;

/**
 * Job to clear a users watchlist in batches.
 *
 * @since 1.31
 * @ingroup JobQueue
 * @author Addshore
 */
class ClearUserWatchlistJob extends Job implements GenericParameterJob {
    /**
     * @param array $params
     *  - userId,         The ID for the user whose watchlist is being cleared.
     *  - maxWatchlistId, The maximum wl_id at the time the job was first created,
     */
    public function __construct( array $params ) {
        parent::__construct( 'clearUserWatchlist', $params );

        $this->removeDuplicates = true;
    }

    /**
     * @param UserIdentity $user User to clear the watchlist for.
     * @param int $maxWatchlistId The maximum wl_id at the time the job was first created.
     *
     * @return ClearUserWatchlistJob
     */
    public static function newForUser( UserIdentity $user, $maxWatchlistId ) {
        return new self( [ 'userId' => $user->getId(), 'maxWatchlistId' => $maxWatchlistId ] );
    }

    public function run() {
        $updateRowsPerQuery = MediaWikiServices::getInstance()->getMainConfig()->get(
            MainConfigNames::UpdateRowsPerQuery );
        $userId = $this->params['userId'];
        $maxWatchlistId = $this->params['maxWatchlistId'];
        $batchSize = $updateRowsPerQuery;

        $loadBalancer = MediaWikiServices::getInstance()->getDBLoadBalancer();
        $dbw = $loadBalancer->getConnection( DB_PRIMARY );
        $dbr = $loadBalancer->getConnection( DB_REPLICA );

        // Wait before lock to try to reduce time waiting in the lock.
        if ( !$loadBalancer->waitForPrimaryPos( $dbr ) ) {
            $this->setLastError( 'Timed out waiting for replica to catch up before lock' );
            return false;
        }

        // Use a named lock so that jobs for this user see each others' changes
        $lockKey = "{{$dbw->getDomainID()}}:ClearUserWatchlist:$userId"; // per-wiki
        $scopedLock = $dbw->getScopedLockAndFlush( $lockKey, __METHOD__, 10 );
        if ( !$scopedLock ) {
            $this->setLastError( "Could not acquire lock '$lockKey'" );
            return false;
        }

        if ( !$loadBalancer->waitForPrimaryPos( $dbr ) ) {
            $this->setLastError( 'Timed out waiting for replica to catch up within lock' );
            return false;
        }

        // Clear any stale REPEATABLE-READ snapshot
        $dbr->flushSnapshot( __METHOD__ );

        $watchlistIds = $dbr->newSelectQueryBuilder()
            ->select( 'wl_id' )
            ->from( 'watchlist' )
            ->where( [ 'wl_user' => $userId ] )
            ->andWhere( $dbr->expr( 'wl_id', '<=', $maxWatchlistId ) )
            ->limit( $batchSize )
            ->caller( __METHOD__ )->fetchFieldValues();
        if ( count( $watchlistIds ) == 0 ) {
            return true;
        }

        $dbw->newDeleteQueryBuilder()
            ->deleteFrom( 'watchlist' )
            ->where( [ 'wl_id' => $watchlistIds ] )
            ->caller( __METHOD__ )->execute();
        if ( MediaWikiServices::getInstance()->getMainConfig()->get( MainConfigNames::WatchlistExpiry ) ) {
            $dbw->newDeleteQueryBuilder()
                ->deleteFrom( 'watchlist_expiry' )
                ->where( [ 'we_item' => $watchlistIds ] )
                ->caller( __METHOD__ )->execute();
        }

        // Commit changes and remove lock before inserting next job.
        $lbf = MediaWikiServices::getInstance()->getDBLoadBalancerFactory();
        $lbf->commitPrimaryChanges( __METHOD__ );
        unset( $scopedLock );

        if ( count( $watchlistIds ) === (int)$batchSize ) {
            // Until we get less results than the limit, recursively push
            // the same job again.
            MediaWikiServices::getInstance()->getJobQueueGroup()->push( new self( $this->getParams() ) );
        }

        return true;
    }

    public function getDeduplicationInfo() {
        $info = parent::getDeduplicationInfo();
        // This job never has a namespace or title so we can't use it for deduplication
        unset( $info['namespace'] );
        unset( $info['title'] );
        return $info;
    }

}
/** @deprecated class alias since 1.43 */
class_alias( ClearUserWatchlistJob::class, 'ClearUserWatchlistJob' );