multi: restructure invoice Terms field

This commit restructures an invoice's ContractTerms to better encompass
the restrictions placed on settling. For instance, the final ctlv delta
and invoice expiry are moved from the main invoice body (where
additional metadata is stored). Additionally, it moves the State field
outside of the terms since it is rather metadata about the invoice
instead of any terms offered to the sender in the payment request.

channeldb/invoice_test.go

@@ -25,12 +25,12 @@ func randInvoice(value lnwire.MilliSatoshi) (*Invoice, error) {
 		// failures due to the monotonic time component.
 		CreationDate: time.Unix(time.Now().Unix(), 0),
 		Terms: ContractTerm{
+			Expiry:          4000,
 			PaymentPreimage: pre,
 			Value:           value,
 			Features:        emptyFeatures,
 		},
-		Htlcs:  map[CircuitKey]*InvoiceHTLC{},
-		Expiry: 4000,
+		Htlcs: map[CircuitKey]*InvoiceHTLC{},
 	}
 	i.Memo = []byte("memo")
 
@@ -114,7 +114,7 @@ func TestInvoiceWorkflow(t *testing.T) {
 	if err != nil {
 		t.Fatalf("unable to fetch invoice: %v", err)
 	}
-	if dbInvoice2.Terms.State != ContractSettled {
+	if dbInvoice2.State != ContractSettled {
 		t.Fatalf("invoice should now be settled but isn't")
 	}
 	if dbInvoice2.SettleDate.IsZero() {
@@ -363,7 +363,7 @@ func TestDuplicateSettleInvoice(t *testing.T) {
 	// We'll update what we expect the settle invoice to be so that our
 	// comparison below has the correct assumption.
 	invoice.SettleIndex = 1
-	invoice.Terms.State = ContractSettled
+	invoice.State = ContractSettled
 	invoice.AmtPaid = amt
 	invoice.SettleDate = dbInvoice.SettleDate
 	invoice.Htlcs = map[CircuitKey]*InvoiceHTLC{
@@ -679,7 +679,7 @@ func TestQueryInvoices(t *testing.T) {
 // settles the invoice with the given amount.
 func getUpdateInvoice(amt lnwire.MilliSatoshi) InvoiceUpdateCallback {
 	return func(invoice *Invoice) (*InvoiceUpdateDesc, error) {
-		if invoice.Terms.State == ContractSettled {
+		if invoice.State == ContractSettled {
 			return nil, ErrInvoiceAlreadySettled
 		}
 

channeldb/invoices.go

@@ -166,6 +166,13 @@ func (c ContractState) String() string {
 // the necessary conditions required before the invoice can be considered fully
 // settled by the payee.
 type ContractTerm struct {
+	// FinalCltvDelta is the minimum required number of blocks before htlc
+	// expiry when the invoice is accepted.
+	FinalCltvDelta int32
+
+	// Expiry defines how long after creation this invoice should expire.
+	Expiry time.Duration
+
 	// PaymentPreimage is the preimage which is to be revealed in the
 	// occasion that an HTLC paying to the hash of this preimage is
 	// extended.
@@ -175,9 +182,6 @@ type ContractTerm struct {
 	// which can be satisfied by the above preimage.
 	Value lnwire.MilliSatoshi
 
-	// State describes the state the invoice is in.
-	State ContractState
-
 	// PaymentAddr is a randomly generated value include in the MPP record
 	// by the sender to prevent probing of the receiver.
 	PaymentAddr [32]byte
@@ -206,13 +210,6 @@ type Invoice struct {
 	// for this invoice can be stored.
 	PaymentRequest []byte
 
-	// FinalCltvDelta is the minimum required number of blocks before htlc
-	// expiry when the invoice is accepted.
-	FinalCltvDelta int32
-
-	// Expiry defines how long after creation this invoice should expire.
-	Expiry time.Duration
-
 	// CreationDate is the exact time the invoice was created.
 	CreationDate time.Time
 
@@ -245,6 +242,9 @@ type Invoice struct {
 	// NOTE: This index starts at 1.
 	SettleIndex uint64
 
+	// State describes the state the invoice is in.
+	State ContractState
+
 	// AmtPaid is the final amount that we ultimately accepted for pay for
 	// this invoice. We specify this value independently as it's possible
 	// that the invoice originally didn't specify an amount, or the sender
@@ -552,7 +552,7 @@ func (d *DB) FetchAllInvoices(pendingOnly bool) ([]Invoice, error) {
 			}
 
 			if pendingOnly &&
-				invoice.Terms.State == ContractSettled {
+				invoice.State == ContractSettled {
 
 				return nil
 			}
@@ -702,7 +702,7 @@ func (d *DB) QueryInvoices(q InvoiceQuery) (InvoiceSlice, error) {
 			// Skip any settled invoices if the caller is only
 			// interested in unsettled.
 			if q.PendingOnly &&
-				invoice.Terms.State == ContractSettled {
+				invoice.State == ContractSettled {
 
 				continue
 			}
@@ -931,11 +931,11 @@ func serializeInvoice(w io.Writer, i *Invoice) error {
 
 	preimage := [32]byte(i.Terms.PaymentPreimage)
 	value := uint64(i.Terms.Value)
-	cltvDelta := uint32(i.FinalCltvDelta)
-	expiry := uint64(i.Expiry)
+	cltvDelta := uint32(i.Terms.FinalCltvDelta)
+	expiry := uint64(i.Terms.Expiry)
 
 	amtPaid := uint64(i.AmtPaid)
-	state := uint8(i.Terms.State)
+	state := uint8(i.State)
 
 	tlvStream, err := tlv.NewStream(
 		// Memo and payreq.
@@ -1094,10 +1094,10 @@ func deserializeInvoice(r io.Reader) (Invoice, error) {
 
 	i.Terms.PaymentPreimage = lntypes.Preimage(preimage)
 	i.Terms.Value = lnwire.MilliSatoshi(value)
-	i.FinalCltvDelta = int32(cltvDelta)
-	i.Expiry = time.Duration(expiry)
+	i.Terms.FinalCltvDelta = int32(cltvDelta)
+	i.Terms.Expiry = time.Duration(expiry)
 	i.AmtPaid = lnwire.MilliSatoshi(amtPaid)
-	i.Terms.State = ContractState(state)
+	i.State = ContractState(state)
 
 	err = i.CreationDate.UnmarshalBinary(creationDateBytes)
 	if err != nil {
@@ -1198,13 +1198,12 @@ func copyInvoice(src *Invoice) *Invoice {
 	dest := Invoice{
 		Memo:           copySlice(src.Memo),
 		PaymentRequest: copySlice(src.PaymentRequest),
-		FinalCltvDelta: src.FinalCltvDelta,
-		Expiry:         src.Expiry,
 		CreationDate:   src.CreationDate,
 		SettleDate:     src.SettleDate,
 		Terms:          src.Terms,
 		AddIndex:       src.AddIndex,
 		SettleIndex:    src.SettleIndex,
+		State:          src.State,
 		AmtPaid:        src.AmtPaid,
 		Htlcs: make(
 			map[CircuitKey]*InvoiceHTLC, len(src.Htlcs),
@@ -1230,7 +1229,7 @@ func (d *DB) updateInvoice(hash lntypes.Hash, invoices, settleIndex *bbolt.Bucke
 		return nil, err
 	}
 
-	preUpdateState := invoice.Terms.State
+	preUpdateState := invoice.State
 
 	// Create deep copy to prevent any accidental modification in the
 	// callback.
@@ -1243,7 +1242,7 @@ func (d *DB) updateInvoice(hash lntypes.Hash, invoices, settleIndex *bbolt.Bucke
 	}
 
 	// Update invoice state.
-	invoice.Terms.State = update.State
+	invoice.State = update.State
 
 	now := d.now()
 
@@ -1291,8 +1290,8 @@ func (d *DB) updateInvoice(hash lntypes.Hash, invoices, settleIndex *bbolt.Bucke
 
 	// If invoice moved to the settled state, update settle index and settle
 	// time.
-	if preUpdateState != invoice.Terms.State &&
-		invoice.Terms.State == ContractSettled {
+	if preUpdateState != invoice.State &&
+		invoice.State == ContractSettled {
 
 		if update.Preimage.Hash() != hash {
 			return nil, fmt.Errorf("preimage does not match")
@@ -1344,7 +1343,7 @@ func setSettleFields(settleIndex *bbolt.Bucket, invoiceNum []byte,
 		return err
 	}
 
-	invoice.Terms.State = ContractSettled
+	invoice.State = ContractSettled
 	invoice.SettleDate = now
 	invoice.SettleIndex = nextSettleSeqNo