PHPDaemon\Clients\Mongo\Pool::evaluate PHP Method

    public function evaluate($code, $cb)
    {
        $p = [];
        if (!isset($p['offset'])) {
            $p['offset'] = 0;
        }
        if (!isset($p['limit'])) {
            $p['limit'] = -1;
        }
        if (!isset($p['opts'])) {
            $p['opts'] = 0;
        }
        if (!isset($p['db'])) {
            $p['db'] = $this->dbname;
        }
        $cb = CallbackWrapper::wrap($cb);
        try {
            $this->request(self::OP_QUERY, pack('V', $p['opts']) . $p['db'] . '.$cmd' . "" . pack('VV', $p['offset'], $p['limit']) . bson_encode(['$eval' => new \MongoCode($code)]) . (isset($p['fields']) ? bson_encode($p['fields']) : ''), true, null, function ($conn, $reqId = null) use($p, $cb) {
                if (!$conn) {
                    !$cb || $cb(['$err' => 'Connection error.']);
                    return;
                }
                $conn->requests[$reqId] = [$p['db'], $cb, true];
            });
        } catch (\MongoException $e) {
            Daemon::log('MongoClient exception: ' . $e->getMessage() . ': ' . $e->getTraceAsString());
            if ($cb !== null) {
                $cb(['$err' => $e->getMessage(), '$query' => $query, '$fields' => isset($p['fields']) ? $p['fields'] : null]);
            }
        }
    }