From 5ed31b1030176374d4184fee0b80ae7679e0e355 Mon Sep 17 00:00:00 2001
From: "Johan T. Halseth" <johanth@gmail.com>
Date: Tue, 5 Sep 2017 17:59:52 +0200
Subject: [PATCH] channeldb: store payment request with invoices

---
 channeldb/invoice_test.go  | 14 ++++++++++++++
 channeldb/invoices.go      | 23 +++++++++++++++++++++++
 channeldb/payments_test.go |  9 ++++++---
 3 files changed, 43 insertions(+), 3 deletions(-)

diff --git a/channeldb/invoice_test.go b/channeldb/invoice_test.go
index b29102fba8..901ad86ca7 100644
--- a/channeldb/invoice_test.go
+++ b/channeldb/invoice_test.go
@@ -29,6 +29,19 @@ func randInvoice(value lnwire.MilliSatoshi) (*Invoice, error) {
 	i.Memo = []byte("memo")
 	i.Receipt = []byte("recipt")
 
+	// Create a random byte slice of MaxPaymentRequestSize bytes to be used
+	// as a dummy paymentrequest, and  determine if it should be set based
+	// on one of the random bytes.
+	var r [MaxPaymentRequestSize]byte
+	if _, err := rand.Read(r[:]); err != nil {
+		return nil, err
+	}
+	if r[0]&1 == 0 {
+		i.PaymentRequest = r[:]
+	} else {
+		i.PaymentRequest = []byte("")
+	}
+
 	return i, nil
 }
 
@@ -50,6 +63,7 @@ func TestInvoiceWorkflow(t *testing.T) {
 	}
 	fakeInvoice.Memo = []byte("memo")
 	fakeInvoice.Receipt = []byte("recipt")
+	fakeInvoice.PaymentRequest = []byte("")
 	copy(fakeInvoice.Terms.PaymentPreimage[:], rev[:])
 	fakeInvoice.Terms.Value = lnwire.NewMSatFromSatoshis(10000)
 
diff --git a/channeldb/invoices.go b/channeldb/invoices.go
index 1add908797..98cc194311 100644
--- a/channeldb/invoices.go
+++ b/channeldb/invoices.go
@@ -43,6 +43,12 @@ const (
 	// MaxReceiptSize is the maximum size of the payment receipt stored
 	// within the database along side incoming/outgoing invoices.
 	MaxReceiptSize = 1024
+
+	// MaxPaymentRequestSize is the max size of a a payment request for
+	// this invoice.
+	// TODO(halseth): determine the max length payment request when field
+	// lengths are final.
+	MaxPaymentRequestSize = 4096
 )
 
 // ContractTerm is a companion struct to the Invoice struct. This struct houses
@@ -86,6 +92,10 @@ type Invoice struct {
 	// TODO(roasbeef): document scheme.
 	Receipt []byte
 
+	// PaymentRequest is an optional field where a payment request created
+	// for this invoice can be stored.
+	PaymentRequest []byte
+
 	// CreationDate is the exact time the invoice was created.
 	CreationDate time.Time
 
@@ -108,6 +118,11 @@ func validateInvoice(i *Invoice) error {
 			"of length %v was provided", MaxReceiptSize,
 			len(i.Receipt))
 	}
+	if len(i.PaymentRequest) > MaxPaymentRequestSize {
+		return fmt.Errorf("max length of payment request is %v, length "+
+			"provided was %v", MaxPaymentRequestSize,
+			len(i.PaymentRequest))
+	}
 	return nil
 }
 
@@ -306,6 +321,9 @@ func serializeInvoice(w io.Writer, i *Invoice) error {
 	if err := wire.WriteVarBytes(w, 0, i.Receipt[:]); err != nil {
 		return err
 	}
+	if err := wire.WriteVarBytes(w, 0, i.PaymentRequest[:]); err != nil {
+		return err
+	}
 
 	birthBytes, err := i.CreationDate.MarshalBinary()
 	if err != nil {
@@ -361,6 +379,11 @@ func deserializeInvoice(r io.Reader) (*Invoice, error) {
 		return nil, err
 	}
 
+	invoice.PaymentRequest, err = wire.ReadVarBytes(r, 0, MaxPaymentRequestSize, "")
+	if err != nil {
+		return nil, err
+	}
+
 	birthBytes, err := wire.ReadVarBytes(r, 0, 300, "birth")
 	if err != nil {
 		return nil, err
diff --git a/channeldb/payments_test.go b/channeldb/payments_test.go
index f84572c276..8c17414df2 100644
--- a/channeldb/payments_test.go
+++ b/channeldb/payments_test.go
@@ -17,9 +17,10 @@ func makeFakePayment() *OutgoingPayment {
 	fakeInvoice := &Invoice{
 		// Use single second precision to avoid false positive test
 		// failures due to the monotonic time component.
-		CreationDate: time.Unix(time.Now().Unix(), 0),
-		Memo:         []byte("fake memo"),
-		Receipt:      []byte("fake receipt"),
+		CreationDate:   time.Unix(time.Now().Unix(), 0),
+		Memo:           []byte("fake memo"),
+		Receipt:        []byte("fake receipt"),
+		PaymentRequest: []byte(""),
 	}
 
 	copy(fakeInvoice.Terms.PaymentPreimage[:], rev[:])
@@ -69,6 +70,8 @@ func makeRandomFakePayment() (*OutgoingPayment, error) {
 		return nil, err
 	}
 
+	fakeInvoice.PaymentRequest = []byte("")
+
 	preImg, err := randomBytes(32, 33)
 	if err != nil {
 		return nil, err