From a86308cb0bed12a0eaec50ee0f8cab06dec279df Mon Sep 17 00:00:00 2001
From: a_bennassar <arnaubennassar5@gmail.com>
Date: Thu, 13 Aug 2020 12:19:01 +0200
Subject: [PATCH] Add scanner/valuer interface to PublicKey

---
 babyjub/eddsa.go      | 25 +++++++++++++++++++++++++
 babyjub/eddsa_test.go | 17 ++++++++++++++++-
 2 files changed, 41 insertions(+), 1 deletion(-)

diff --git a/babyjub/eddsa.go b/babyjub/eddsa.go
index e2cf78c..e6acbf0 100644
--- a/babyjub/eddsa.go
+++ b/babyjub/eddsa.go
@@ -283,3 +283,28 @@ func (p *PublicKey) VerifyPoseidon(msg *big.Int, sig *Signature) bool {
 	right.Add(sig.R8, right) // right = 8 * R + 8 * hm * A
 	return (left.X.Cmp(right.X) == 0) && (left.Y.Cmp(right.Y) == 0)
 }
+
+// Scan implements Scanner for database/sql.
+func (p *PublicKey) Scan(src interface{}) error {
+	srcB, ok := src.([]byte)
+	if !ok {
+		return fmt.Errorf("can't scan %T into PublicKey", src)
+	}
+	if len(srcB) != 32 {
+		return fmt.Errorf("can't scan []byte of len %d into PublicKey, want %d", len(srcB), 32)
+	}
+	var comp PublicKeyComp
+	copy(comp[:], srcB)
+	decomp, err := comp.Decompress()
+	if err != nil {
+		return err
+	}
+	*p = *decomp
+	return nil
+}
+
+// Value implements valuer for database/sql.
+func (p *PublicKey) Value() (driver.Value, error) {
+	comp := p.Compress()
+	return comp[:], nil
+}
diff --git a/babyjub/eddsa_test.go b/babyjub/eddsa_test.go
index 8de435c..1989785 100644
--- a/babyjub/eddsa_test.go
+++ b/babyjub/eddsa_test.go
@@ -135,7 +135,7 @@ func TestCompressDecompress(t *testing.T) {
 	}
 }
 
-func TestScannerValuer(t *testing.T) {
+func TestSignatureScannerValuer(t *testing.T) {
 	privK := NewRandPrivKey()
 	var value driver.Valuer
 	var scan sql.Scanner
@@ -147,6 +147,21 @@ func TestScannerValuer(t *testing.T) {
 	assert.Equal(t, value, scan)
 }
 
+func TestPubKeyScannerValuer(t *testing.T) {
+	privKValue := NewRandPrivKey()
+	pubKValue := privKValue.Public()
+	privKScan := NewRandPrivKey()
+	pubKScan := privKScan.Public()
+	var value driver.Valuer
+	var scan sql.Scanner
+	value = pubKValue
+	scan = pubKScan
+	fromDB, err := value.Value()
+	assert.NoError(t, err)
+	assert.NoError(t, scan.Scan(fromDB))
+	assert.Equal(t, value, scan)
+}
+
 func BenchmarkBabyjubEddsa(b *testing.B) {
 	var k PrivateKey
 	_, err := hex.Decode(k[:], []byte("0001020304050607080900010203040506070809000102030405060708090001"))