From a366175021136a38c5f6b4dd64b91214baa8757f Mon Sep 17 00:00:00 2001
From: arnaucube <root@arnaucube.com>
Date: Fri, 18 Dec 2020 20:44:29 +0100
Subject: [PATCH] Add scanner/valuer interface to babyjub.PublicKeyComp

---
 babyjub/eddsa.go      | 18 ++++++++++++++++++
 babyjub/eddsa_test.go | 17 ++++++++++++++++-
 2 files changed, 34 insertions(+), 1 deletion(-)

diff --git a/babyjub/eddsa.go b/babyjub/eddsa.go
index 55f250c..feee8ca 100644
--- a/babyjub/eddsa.go
+++ b/babyjub/eddsa.go
@@ -354,3 +354,21 @@ func (pk PublicKey) Value() (driver.Value, error) {
 	comp := pk.Compress()
 	return comp[:], nil
 }
+
+// Scan implements Scanner for database/sql.
+func (pkComp *PublicKeyComp) Scan(src interface{}) error {
+	srcB, ok := src.([]byte)
+	if !ok {
+		return fmt.Errorf("can't scan %T into PublicKeyComp", src)
+	}
+	if len(srcB) != 32 {
+		return fmt.Errorf("can't scan []byte of len %d into PublicKeyComp, want %d", len(srcB), 32)
+	}
+	copy(pkComp[:], srcB)
+	return nil
+}
+
+// Value implements valuer for database/sql.
+func (pkComp PublicKeyComp) Value() (driver.Value, error) {
+	return pkComp[:], nil
+}
diff --git a/babyjub/eddsa_test.go b/babyjub/eddsa_test.go
index 978c428..495f990 100644
--- a/babyjub/eddsa_test.go
+++ b/babyjub/eddsa_test.go
@@ -160,7 +160,7 @@ func TestSignatureScannerValuer(t *testing.T) {
 	assert.Equal(t, value, scan)
 }
 
-func TestPubKeyScannerValuer(t *testing.T) {
+func TestPublicKeyScannerValuer(t *testing.T) {
 	privKValue := NewRandPrivKey()
 	pubKValue := privKValue.Public()
 	privKScan := NewRandPrivKey()
@@ -175,6 +175,21 @@ func TestPubKeyScannerValuer(t *testing.T) {
 	assert.Equal(t, value, scan)
 }
 
+func TestPublicKeyCompScannerValuer(t *testing.T) {
+	privKValue := NewRandPrivKey()
+	pubKCompValue := privKValue.Public().Compress()
+	privKScan := NewRandPrivKey()
+	pubKCompScan := privKScan.Public().Compress()
+	var value driver.Valuer
+	var scan sql.Scanner
+	value = &pubKCompValue
+	scan = &pubKCompScan
+	fromDB, err := value.Value()
+	assert.Nil(t, err)
+	assert.Nil(t, scan.Scan(fromDB))
+	assert.Equal(t, value, scan)
+}
+
 func BenchmarkBabyjubEddsa(b *testing.B) {
 	var k PrivateKey
 	_, err := hex.Decode(k[:],