WANCacheReapUpdate.php

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<?php
 
use Psr\Log\LoggerInterface;
use Wikimedia\Rdbms\IDatabase;
 
class WANCacheReapUpdate implements DeferrableUpdate {
    private $db;
    private $logger;
 
    public function __construct( IDatabase $db, LoggerInterface $logger ) {
        $this->db = $db;
        $this->logger = $logger;
    }
 
    function doUpdate() {
        $reaper = new WANObjectCacheReaper(
            ObjectCache::getMainWANInstance(),
            ObjectCache::getLocalClusterInstance(),
            [ $this, 'getTitleChangeEvents' ],
            [ $this, 'getEventAffectedKeys' ],
            [
                'channel' => 'table:recentchanges:' . $this->db->getDomainID(),
                'logger' => $this->logger
            ]
        );
 
        $reaper->invoke( 100 );
    }
 
    public function getTitleChangeEvents( $start, $id, $end, $limit ) {
        $db = $this->db;
        $encStart = $db->addQuotes( $db->timestamp( $start ) );
        $encEnd = $db->addQuotes( $db->timestamp( $end ) );
        $id = (int)$id; // cast NULL => 0 since rc_id is an integer
 
        $res = $db->select(
            'recentchanges',
            [ 'rc_namespace', 'rc_title', 'rc_timestamp', 'rc_id' ],
            [
                $db->makeList( [
                    "rc_timestamp > $encStart",
                    "rc_timestamp = $encStart AND rc_id > " . $db->addQuotes( $id )
                ], LIST_OR ),
                "rc_timestamp < $encEnd"
            ],
            __METHOD__,
            [ 'ORDER BY' => 'rc_timestamp ASC, rc_id ASC', 'LIMIT' => $limit ]
        );
 
        $events = [];
        foreach ( $res as $row ) {
            $events[] = [
                'id' => (int)$row->rc_id,
                'pos' => (int)wfTimestamp( TS_UNIX, $row->rc_timestamp ),
                'item' => new TitleValue( (int)$row->rc_namespace, $row->rc_title )
            ];
        }
 
        return $events;
    }
 
    public function getEventAffectedKeys( WANObjectCache $cache, TitleValue $t ) {
        $entities = [];
 
        // You can't create a WikiPage for special pages (-1) or other virtual
        // namespaces, but special pages do appear in RC sometimes, e.g. for logs
        // of AbuseFilter filter changes.
        if ( $t->getNamespace() >= 0 ) {
            $entities[] = WikiPage::factory( Title::newFromTitleValue( $t ) );
        }
 
        if ( $t->inNamespace( NS_FILE ) ) {
            $entities[] = wfLocalFile( $t->getText() );
        }
        if ( $t->inNamespace( NS_USER ) ) {
            $entities[] = User::newFromName( $t->getText(), false );
        }
 
        $keys = [];
        foreach ( $entities as $entity ) {
            if ( $entity ) {
                $keys = array_merge( $keys, $entity->getMutableCacheKeys( $cache ) );
            }
        }
        if ( $keys ) {
            $this->logger->debug( __CLASS__ . ': got key(s) ' . implode( ', ', $keys ) );
        }
 
        return $keys;
    }
}