routerrpc: bring back legacy track and send rpcs

To soften the transition for routerrpc users to the V2 messages.

lnrpc/routerrpc/router_server_deprecated.go

@@ -0,0 +1,95 @@
+package routerrpc
+
+import (
+	"encoding/hex"
+	"errors"
+	"fmt"
+
+	"github.com/lightningnetwork/lnd/lnrpc"
+)
+
+// legacyTrackPaymentServer is a wrapper struct that transforms a stream of main
+// rpc payment structs into the legacy PaymentStatus format.
+type legacyTrackPaymentServer struct {
+	Router_TrackPaymentServer
+}
+
+// Send converts a Payment object and sends it as a PaymentStatus object on the
+// embedded stream.
+func (i *legacyTrackPaymentServer) Send(p *lnrpc.Payment) error {
+	var state PaymentState
+	switch p.Status {
+	case lnrpc.Payment_IN_FLIGHT:
+		state = PaymentState_IN_FLIGHT
+	case lnrpc.Payment_SUCCEEDED:
+		state = PaymentState_SUCCEEDED
+	case lnrpc.Payment_FAILED:
+		switch p.FailureReason {
+		case lnrpc.PaymentFailureReason_FAILURE_REASON_NONE:
+			return fmt.Errorf("expected fail reason")
+
+		case lnrpc.PaymentFailureReason_FAILURE_REASON_TIMEOUT:
+			state = PaymentState_FAILED_TIMEOUT
+
+		case lnrpc.PaymentFailureReason_FAILURE_REASON_NO_ROUTE:
+			state = PaymentState_FAILED_NO_ROUTE
+
+		case lnrpc.PaymentFailureReason_FAILURE_REASON_ERROR:
+			state = PaymentState_FAILED_ERROR
+
+		case lnrpc.PaymentFailureReason_FAILURE_REASON_INCORRECT_PAYMENT_DETAILS:
+			state = PaymentState_FAILED_INCORRECT_PAYMENT_DETAILS
+
+		case lnrpc.PaymentFailureReason_FAILURE_REASON_INSUFFICIENT_BALANCE:
+			state = PaymentState_FAILED_INSUFFICIENT_BALANCE
+
+		default:
+			return fmt.Errorf("unknown failure reason %v",
+				p.FailureReason)
+		}
+	default:
+		return fmt.Errorf("unknown state %v", p.Status)
+	}
+
+	preimage, err := hex.DecodeString(p.PaymentPreimage)
+	if err != nil {
+		return err
+	}
+
+	legacyState := PaymentStatus{
+		State:    state,
+		Preimage: preimage,
+		Htlcs:    p.Htlcs,
+	}
+
+	return i.Router_TrackPaymentServer.Send(&legacyState)
+}
+
+// TrackPayment returns a stream of payment state updates. The stream is
+// closed when the payment completes.
+func (s *Server) TrackPayment(request *TrackPaymentRequest,
+	stream Router_TrackPaymentServer) error {
+
+	legacyStream := legacyTrackPaymentServer{
+		Router_TrackPaymentServer: stream,
+	}
+	return s.TrackPaymentV2(request, &legacyStream)
+}
+
+// SendPayment attempts to route a payment described by the passed
+// PaymentRequest to the final destination. If we are unable to route the
+// payment, or cannot find a route that satisfies the constraints in the
+// PaymentRequest, then an error will be returned. Otherwise, the payment
+// pre-image, along with the final route will be returned.
+func (s *Server) SendPayment(request *SendPaymentRequest,
+	stream Router_SendPaymentServer) error {
+
+	if request.MaxShards > 1 {
+		return errors.New("for multi-part payments, use SendPaymentV2")
+	}
+
+	legacyStream := legacyTrackPaymentServer{
+		Router_TrackPaymentServer: stream,
+	}
+	return s.SendPaymentV2(request, &legacyStream)
+}