From 62ee8f90498188ca9a4d0f2ae3060244bcbf0111 Mon Sep 17 00:00:00 2001
From: krehermann <keith.rehermann@smartcontract.com>
Date: Fri, 2 Jun 2023 15:50:41 -0600
Subject: [PATCH] Simply KeystoreAdapter interface (#297)

---
 relayer/pkg/chainlink/txm/keystore.go      | 26 +++++------
 relayer/pkg/chainlink/txm/keystore_test.go | 51 ++++++++++++++++++++++
 2 files changed, 62 insertions(+), 15 deletions(-)
 create mode 100644 relayer/pkg/chainlink/txm/keystore_test.go

diff --git a/relayer/pkg/chainlink/txm/keystore.go b/relayer/pkg/chainlink/txm/keystore.go
index 59607c54c..6881ac77d 100644
--- a/relayer/pkg/chainlink/txm/keystore.go
+++ b/relayer/pkg/chainlink/txm/keystore.go
@@ -2,6 +2,7 @@ package txm
 
 import (
 	"context"
+	"errors"
 	"fmt"
 	"math/big"
 
@@ -13,42 +14,37 @@ import (
 
 // KeystoreAdapter is a starknet-specific adaption layer to translate between the generic Loop Keystore (bytes) and
 // the type specific caigo Keystore (big.Int)
-// The loop.Keystore must be produce a byte representation that can be parsed by the Decode func implementation
-// Users of the interface are responsible to ensure this compatibility.
 type KeystoreAdapter interface {
 	caigo.Keystore
-	// Loopp must return a LOOPp Keystore implementation whose Sign func
-	// is compatible with the [Decode] func implementation
 	Loopp() loop.Keystore
-	// Decode translates from the raw signature of the LOOPp Keystore to that of the Caigo Keystore
-	Decode(ctx context.Context, rawSignature []byte) (*big.Int, *big.Int, error)
 }
 
-// keystoreAdapter implements [KeystoreAdapter]
+// keystoreAdapter implements [KeystoreAdapter].
 type keystoreAdapter struct {
 	looppKs loop.Keystore
 }
 
 // NewKeystoreAdapter instantiates the KeystoreAdapter interface
+// The implementation requires that the given [looppKs] produces a signature [loop.Keystore.Sign]
+// that is []byte representation of [adapters.Signature]
 // Callers are responsible for ensuring that the given LOOPp Keystore encodes
-// signatures that can be parsed by the Decode function
+// signatures correctly.
 func NewKeystoreAdapter(lk loop.Keystore) KeystoreAdapter {
 	return &keystoreAdapter{looppKs: lk}
 }
 
-// Sign implements the caigo Keystore Sign func.
+var ErrBadAdapterEncoding = errors.New("failed to decode raw signature as adapter signature")
+
+// Sign implements the caigo Keystore Sign func. Returns [ErrBadAdapterSignature] if the signature cannot be
+// decoded from the [loop.Keystore] implementation
 func (ca *keystoreAdapter) Sign(ctx context.Context, senderAddress string, hash *big.Int) (*big.Int, *big.Int, error) {
 	raw, err := ca.looppKs.Sign(ctx, senderAddress, hash.Bytes())
 	if err != nil {
 		return nil, nil, fmt.Errorf("error computing loopp keystore signature: %w", err)
 	}
-	return ca.Decode(ctx, raw)
-}
-
-func (ca *keystoreAdapter) Decode(ctx context.Context, rawSignature []byte) (x *big.Int, y *big.Int, err error) {
-	starknetSig, serr := adapters.SignatureFromBytes(rawSignature)
+	starknetSig, serr := adapters.SignatureFromBytes(raw)
 	if serr != nil {
-		return nil, nil, fmt.Errorf("error creating starknet signature from raw signature: %w", serr)
+		return nil, nil, fmt.Errorf("%w: %w", ErrBadAdapterEncoding, serr)
 	}
 	return starknetSig.Ints()
 }
diff --git a/relayer/pkg/chainlink/txm/keystore_test.go b/relayer/pkg/chainlink/txm/keystore_test.go
new file mode 100644
index 000000000..f68353380
--- /dev/null
+++ b/relayer/pkg/chainlink/txm/keystore_test.go
@@ -0,0 +1,51 @@
+package txm_test
+
+import (
+	"context"
+	"math/big"
+	"testing"
+
+	"github.com/stretchr/testify/require"
+
+	"github.com/smartcontractkit/chainlink-relay/pkg/loop"
+	adapters "github.com/smartcontractkit/chainlink-relay/pkg/loop/adapters/starknet"
+	"github.com/smartcontractkit/chainlink-starknet/relayer/pkg/chainlink/txm"
+)
+
+func TestKeystoreAdapterImpl(t *testing.T) {
+	t.Run("valid loop keystore impl", func(t *testing.T) {
+		goodLoopSignFn := func(ctx context.Context, account string, data []byte) (signed []byte, err error) {
+			sig, err := adapters.SignatureFromBigInts(big.NewInt(7), big.NewInt(11))
+			require.NoError(t, err)
+			return sig.Bytes()
+		}
+		ksa := txm.NewKeystoreAdapter(&testLoopKeystore{signFn: goodLoopSignFn})
+
+		_, _, err := ksa.Sign(context.Background(), "anything", big.NewInt(42))
+		require.NoError(t, err)
+	})
+	t.Run("invalid loop keystore impl", func(t *testing.T) {
+		badLoopSignFn := func(ctx context.Context, account string, data []byte) (signed []byte, err error) {
+			return []byte("not an adapter signature"), nil
+		}
+		ksa := txm.NewKeystoreAdapter(&testLoopKeystore{signFn: badLoopSignFn})
+
+		_, _, err := ksa.Sign(context.Background(), "anything", big.NewInt(42))
+		require.ErrorIs(t, err, txm.ErrBadAdapterEncoding)
+	})
+
+}
+
+type testLoopKeystore struct {
+	signFn func(ctx context.Context, account string, data []byte) (signed []byte, err error)
+}
+
+var _ loop.Keystore = &testLoopKeystore{}
+
+func (lk *testLoopKeystore) Sign(ctx context.Context, account string, data []byte) (signed []byte, err error) {
+	return lk.signFn(ctx, account, data)
+}
+
+func (lk *testLoopKeystore) Accounts(ctx context.Context) (accounts []string, err error) {
+	return nil, nil
+}