LoadBalancerSingle.php

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<?php
namespace Wikimedia\Rdbms;
 
use InvalidArgumentException;
 
class LoadBalancerSingle extends LoadBalancer {
    private $conn;
 
    public function __construct( array $params ) {
        $conn = $params['connection'] ?? null;
        if ( !$conn ) {
            throw new InvalidArgumentException( "Missing 'connection' argument." );
        }
 
        $this->conn = $conn;
 
        parent::__construct( [
            'servers' => [ [
                'type' => $conn->getType(),
                'host' => $conn->getServer(),
                'dbname' => $conn->getDBname(),
                'load' => 1,
            ] ],
            'trxProfiler' => $params['trxProfiler'] ?? null,
            'srvCache' => $params['srvCache'] ?? null,
            'wanCache' => $params['wanCache'] ?? null,
            'localDomain' => $params['localDomain'] ?? $this->conn->getDomainID(),
            'readOnlyReason' => $params['readOnlyReason'] ?? false,
            'clusterName' => $params['clusterName'] ?? null,
        ] );
 
        if ( isset( $params['readOnlyReason'] ) ) {
            $conn->setLBInfo( $conn::LB_READ_ONLY_REASON, $params['readOnlyReason'] );
        }
    }
 
    public static function newFromConnection( IDatabase $db, array $params = [] ) {
        return new static( array_merge(
            [ 'localDomain' => $db->getDomainID() ],
            $params,
            [ 'connection' => $db ]
        ) );
    }
 
    protected function sanitizeConnectionFlags( $flags, $domain ) {
        // There is only one underlying connection handle. Also, this class is only meant to
        // be used during situations like site installation, where there should be no contenting
        // connections, and integration testing, where everything uses temporary tables.
        $flags &= ~self::CONN_TRX_AUTOCOMMIT;
 
        return $flags;
    }
 
    protected function reallyOpenConnection( $i, DatabaseDomain $domain, array $lbInfo ) {
        foreach ( $lbInfo as $k => $v ) {
            $this->conn->setLBInfo( $k, $v );
        }
 
        return $this->conn;
    }
 
    public function __destruct() {
        // do nothing since the connection was injected
    }
}