func TestTLSDialerH2()

in transport/tls.go [91:132]
36 lines of code
6 McCabe index (conditional complexity)

func TestTLSDialerH2(
	d testing.Driver,
	forward Dialer,
	config *tlscommon.TLSConfig,
	timeout time.Duration,
) (DialerH2, error) {
	var lastTLSConfig *tls.Config
	var lastNetwork string
	var lastAddress string
	var m sync.Mutex

	return DialerFuncH2(func(ctx context.Context, network, address string, cfg *tls.Config) (net.Conn, error) {
		switch network {
		case "tcp", "tcp4", "tcp6":
		default:
			return nil, fmt.Errorf("unsupported network type %v", network)
		}

		host, _, err := net.SplitHostPort(address)
		if err != nil {
			return nil, err
		}

		var tlsConfig *tls.Config
		m.Lock()
		if network == lastNetwork && address == lastAddress {
			tlsConfig = lastTLSConfig
		}
		if tlsConfig == nil {
			tlsConfig = config.BuildModuleClientConfig(host)
			lastNetwork = network
			lastAddress = address
			lastTLSConfig = tlsConfig
		}
		m.Unlock()

		// NextProtos must be set from the passed h2 connection or it will fail
		tlsConfig.NextProtos = cfg.NextProtos

		return tlsDialWith(ctx, d, forward, network, address, timeout, tlsConfig, config)
	}), nil
}