loopout: create LoopOutSwapInfo struct

client.go

@@ -14,7 +14,6 @@ import (
 	"github.com/lightninglabs/loop/lsat"
 	"github.com/lightninglabs/loop/swap"
 	"github.com/lightninglabs/loop/sweep"
-	"github.com/lightningnetwork/lnd/lntypes"
 )
 
 var (
@@ -354,14 +353,14 @@ func (s *Client) resumeSwaps(ctx context.Context,
 //
 // The return value is a hash that uniquely identifies the new swap.
 func (s *Client) LoopOut(globalCtx context.Context,
-	request *OutRequest) (*lntypes.Hash, btcutil.Address, error) {
+	request *OutRequest) (*LoopOutSwapInfo, error) {
 
 	log.Infof("LoopOut %v to %v (channels: %v)",
 		request.Amount, request.DestAddr, request.OutgoingChanSet,
 	)
 
 	if err := s.waitForInitialized(globalCtx); err != nil {
-		return nil, nil, err
+		return nil, err
 	}
 
 	// Create a new swap object for this swap.
@@ -371,7 +370,7 @@ func (s *Client) LoopOut(globalCtx context.Context,
 		globalCtx, swapCfg, initiationHeight, request,
 	)
 	if err != nil {
-		return nil, nil, err
+		return nil, err
 	}
 
 	// Post swap to the main loop.
@@ -379,7 +378,10 @@ func (s *Client) LoopOut(globalCtx context.Context,
 
 	// Return hash so that the caller can identify this swap in the updates
 	// stream.
-	return &swap.hash, swap.htlc.Address, nil
+	return &LoopOutSwapInfo{
+		SwapHash:         swap.hash,
+		HtlcAddressP2WSH: swap.htlc.Address,
+	}, nil
 }
 
 // LoopOutQuote takes a LoopOut amount and returns a break down of estimated

client_test.go

@@ -45,7 +45,7 @@ func TestSuccess(t *testing.T) {
 	ctx := createClientTestContext(t, nil)
 
 	// Initiate loop out.
-	hash, _, err := ctx.swapClient.LoopOut(context.Background(), testRequest)
+	info, err := ctx.swapClient.LoopOut(context.Background(), testRequest)
 	if err != nil {
 		t.Fatal(err)
 	}
@@ -59,7 +59,7 @@ func TestSuccess(t *testing.T) {
 	// Expect client to register for conf.
 	confIntent := ctx.AssertRegisterConf(false)
 
-	testSuccess(ctx, testRequest.Amount, *hash,
+	testSuccess(ctx, testRequest.Amount, info.SwapHash,
 		signalPrepaymentResult, signalSwapPaymentResult, false,
 		confIntent,
 	)
@@ -72,7 +72,7 @@ func TestFailOffchain(t *testing.T) {
 
 	ctx := createClientTestContext(t, nil)
 
-	_, _, err := ctx.swapClient.LoopOut(context.Background(), testRequest)
+	_, err := ctx.swapClient.LoopOut(context.Background(), testRequest)
 	if err != nil {
 		t.Fatal(err)
 	}
@@ -110,7 +110,7 @@ func TestFailWrongAmount(t *testing.T) {
 		// Modify mock for this subtest.
 		modifier(ctx.serverMock)
 
-		_, _, err := ctx.swapClient.LoopOut(
+		_, err := ctx.swapClient.LoopOut(
 			context.Background(), testRequest,
 		)
 		if err != expectedErr {

interface.go

@@ -250,6 +250,17 @@ type LoopInSwapInfo struct { // nolint
 	HtlcAddressNP2WSH btcutil.Address
 }
 
+// LoopOutSwapInfo contains essential information of a loop-out swap after the
+// swap is initiated.
+type LoopOutSwapInfo struct { // nolint:golint
+	// SwapHash contains the sha256 hash of the swap preimage.
+	SwapHash lntypes.Hash
+
+	// HtlcAddressP2WSH contains the native segwit swap htlc address that
+	// the server will publish to.
+	HtlcAddressP2WSH btcutil.Address
+}
+
 // SwapInfoKit contains common swap info fields.
 type SwapInfoKit struct {
 	// Hash is the sha256 hash of the preimage that unlocks the htlcs. It

loopd/swapclient_server.go

@@ -103,17 +103,17 @@ func (s *swapClientServer) LoopOut(ctx context.Context,
 		req.OutgoingChanSet = in.OutgoingChanSet
 	}
 
-	hash, htlc, err := s.impl.LoopOut(ctx, req)
+	info, err := s.impl.LoopOut(ctx, req)
 	if err != nil {
 		log.Errorf("LoopOut: %v", err)
 		return nil, err
 	}
 
 	return &looprpc.SwapResponse{
-		Id:               hash.String(),
-		IdBytes:          hash[:],
-		HtlcAddress:      htlc.String(),
-		HtlcAddressP2Wsh: htlc.String(),
+		Id:               info.SwapHash.String(),
+		IdBytes:          info.SwapHash[:],
+		HtlcAddress:      info.HtlcAddressP2WSH.String(),
+		HtlcAddressP2Wsh: info.HtlcAddressP2WSH.String(),
 	}, nil
 }