From 5ef832f175301ece8f8facb6c77ce2c1260791d5 Mon Sep 17 00:00:00 2001
From: Arnau B <arnaubennassar5@gmail.com>
Date: Thu, 15 Oct 2020 18:42:55 +0200
Subject: [PATCH] Add scanner/valuer interface to babyjub.SignatureComp

---
 babyjub/eddsa.go      | 18 ++++++++++++++++++
 babyjub/eddsa_test.go | 19 +++++++++++++++----
 go.sum                |  1 +
 3 files changed, 34 insertions(+), 4 deletions(-)

diff --git a/babyjub/eddsa.go b/babyjub/eddsa.go
index b931cd6..8952364 100644
--- a/babyjub/eddsa.go
+++ b/babyjub/eddsa.go
@@ -177,6 +177,24 @@ func (s *SignatureComp) Decompress() (*Signature, error) {
 	return new(Signature).Decompress(*s)
 }
 
+// Scan implements Scanner for database/sql.
+func (s *SignatureComp) Scan(src interface{}) error {
+	srcB, ok := src.([]byte)
+	if !ok {
+		return fmt.Errorf("can't scan %T into Signature", src)
+	}
+	if len(srcB) != 64 {
+		return fmt.Errorf("can't scan []byte of len %d into Signature, want %d", len(srcB), 64)
+	}
+	copy(s[:], srcB[:])
+	return nil
+}
+
+// Value implements valuer for database/sql.
+func (s SignatureComp) Value() (driver.Value, error) {
+	return s[:], nil
+}
+
 // Scan implements Scanner for database/sql.
 func (s *Signature) Scan(src interface{}) error {
 	srcB, ok := src.([]byte)
diff --git a/babyjub/eddsa_test.go b/babyjub/eddsa_test.go
index 2e81fe4..504beb0 100644
--- a/babyjub/eddsa_test.go
+++ b/babyjub/eddsa_test.go
@@ -135,6 +135,17 @@ func TestCompressDecompress(t *testing.T) {
 	}
 }
 
+func TestSignatureCompScannerValuer(t *testing.T) {
+	privK := NewRandPrivKey()
+	var value driver.Valuer //nolint:gosimple this is done to ensure interface compability
+	value = privK.SignPoseidon(big.NewInt(674238462)).Compress()
+	scan := privK.SignPoseidon(big.NewInt(1)).Compress()
+	fromDB, err := value.Value()
+	assert.Nil(t, err)
+	assert.Nil(t, scan.Scan(fromDB))
+	assert.Equal(t, value, scan)
+}
+
 func TestSignatureScannerValuer(t *testing.T) {
 	privK := NewRandPrivKey()
 	var value driver.Valuer
@@ -142,8 +153,8 @@ func TestSignatureScannerValuer(t *testing.T) {
 	value = privK.SignPoseidon(big.NewInt(674238462))
 	scan = privK.SignPoseidon(big.NewInt(1))
 	fromDB, err := value.Value()
-	assert.NoError(t, err)
-	assert.NoError(t, scan.Scan(fromDB))
+	assert.Nil(t, err)
+	assert.Nil(t, scan.Scan(fromDB))
 	assert.Equal(t, value, scan)
 }
 
@@ -157,8 +168,8 @@ func TestPubKeyScannerValuer(t *testing.T) {
 	value = pubKValue
 	scan = pubKScan
 	fromDB, err := value.Value()
-	assert.NoError(t, err)
-	assert.NoError(t, scan.Scan(fromDB))
+	assert.Nil(t, err)
+	assert.Nil(t, scan.Scan(fromDB))
 	assert.Equal(t, value, scan)
 }
 
diff --git a/go.sum b/go.sum
index ff15655..b63d775 100644
--- a/go.sum
+++ b/go.sum
@@ -126,6 +126,7 @@ github.com/steakknife/bloomfilter v0.0.0-20180922174646-6819c0d2a570 h1:gIlAHnH1
 github.com/steakknife/bloomfilter v0.0.0-20180922174646-6819c0d2a570/go.mod h1:8OR4w3TdeIHIh1g6EMY5p0gVNOovcWC+1vpc7naMuAw=
 github.com/steakknife/hamming v0.0.0-20180906055917-c99c65617cd3 h1:njlZPzLwU639dk2kqnCPPv+wNjq7Xb6EfUxe/oX0/NM=
 github.com/steakknife/hamming v0.0.0-20180906055917-c99c65617cd3/go.mod h1:hpGUWaI9xL8pRQCTXQgocU38Qw1g0Us7n5PxxTwTCYU=
+github.com/stretchr/objx v0.1.0 h1:4G4v2dO3VZwixGIRoQ5Lfboy6nUhCyYzaqnIAPPhYs4=
 github.com/stretchr/objx v0.1.0/go.mod h1:HFkY916IF+rwdDfMAkV7OtwuqBVzrE8GR6GFx+wExME=
 github.com/stretchr/testify v1.2.2/go.mod h1:a8OnRcib4nhh0OaRAV+Yts87kKdq0PP7pXfy6kDkUVs=
 github.com/stretchr/testify v1.3.0 h1:TivCn/peBQ7UY8ooIcPgZFpTNSz0Q2U6UrFlUfqbe0Q=