asset: move GroupKeyRevealEncoder and Decoder from proof package

Relocate GroupKeyRevealEncoder and GroupKeyRevealDecoder to the asset
package to allow direct interrogation in unit tests.

Author: ffranr

asset/encoding.go

@@ -895,3 +895,55 @@ func AltLeavesDecoder(r io.Reader, val any, buf *[8]byte, l uint64) error {
 	}
 	return tlv.NewTypeForEncodingErr(val, "[]*AltLeaf")
 }
+
+func GroupKeyRevealEncoder(w io.Writer, val any, _ *[8]byte) error {
+	if t, ok := val.(*GroupKeyReveal); ok {
+		if err := (*t).Encode(w); err != nil {
+			return fmt.Errorf("unable to encode group key "+
+				"reveal: %w", err)
+		}
+
+		return nil
+	}
+
+	return tlv.NewTypeForEncodingErr(val, "GroupKeyReveal")
+}
+
+func GroupKeyRevealDecoder(r io.Reader, val any, buf *[8]byte, l uint64) error {
+	// Return early if the val is not a pointer to a GroupKeyReveal.
+	typ, ok := val.(*GroupKeyReveal)
+	if !ok {
+		return tlv.NewTypeForEncodingErr(val, "GroupKeyReveal")
+	}
+
+	// If the length is less than or equal to the sum of the lengths of the
+	// internal key and the tapscript root, then we'll attempt to decode it
+	// as a GroupKeyRevealV0.
+	internalKeyLen := uint64(btcec.PubKeyBytesLenCompressed)
+	tapscriptRootLen := uint64(sha256.Size)
+
+	if l <= internalKeyLen+tapscriptRootLen {
+		// Attempt decoding with GroupKeyRevealV0.
+		var gkrV0 GroupKeyRevealV0
+
+		err := gkrV0.Decode(r, buf, l)
+		if err != nil {
+			return fmt.Errorf("group key reveal V0 decode "+
+				"error: %w", err)
+		}
+
+		*typ = &gkrV0
+		return nil
+	}
+
+	// Attempt decoding with GroupKeyRevealV1.
+	var gkrV1 GroupKeyRevealV1
+
+	err := gkrV1.Decode(r, buf, l)
+	if err != nil {
+		return fmt.Errorf("group key reveal V1 decode error: %w", err)
+	}
+
+	*typ = &gkrV1
+	return nil
+}

proof/encoding.go

@@ -2,13 +2,11 @@ package proof
 
 import (
 	"bytes"
-	"crypto/sha256"
 	"fmt"
 	"io"
 	"math"
 
 	"github.com/btcsuite/btcd/blockchain"
-	"github.com/btcsuite/btcd/btcec/v2"
 	"github.com/btcsuite/btcd/wire"
 	"github.com/lightninglabs/taproot-assets/asset"
 	"github.com/lightningnetwork/lnd/tlv"
@@ -465,55 +463,3 @@ func GenesisRevealDecoder(r io.Reader, val any, buf *[8]byte, l uint64) error {
 
 	return tlv.NewTypeForEncodingErr(val, "GenesisReveal")
 }
-
-func GroupKeyRevealEncoder(w io.Writer, val any, _ *[8]byte) error {
-	if t, ok := val.(*asset.GroupKeyReveal); ok {
-		if err := (*t).Encode(w); err != nil {
-			return fmt.Errorf("unable to encode group key "+
-				"reveal: %w", err)
-		}
-
-		return nil
-	}
-
-	return tlv.NewTypeForEncodingErr(val, "GroupKeyReveal")
-}
-
-func GroupKeyRevealDecoder(r io.Reader, val any, buf *[8]byte, l uint64) error {
-	// Return early if the val is not a pointer to a GroupKeyReveal.
-	typ, ok := val.(*asset.GroupKeyReveal)
-	if !ok {
-		return tlv.NewTypeForEncodingErr(val, "GroupKeyReveal")
-	}
-
-	// If the length is less than or equal to the sum of the lengths of the
-	// internal key and the tapscript root, then we'll attempt to decode it
-	// as a GroupKeyRevealV0.
-	internalKeyLen := uint64(btcec.PubKeyBytesLenCompressed)
-	tapscriptRootLen := uint64(sha256.Size)
-
-	if l <= internalKeyLen+tapscriptRootLen {
-		// Attempt decoding with GroupKeyRevealV0.
-		var gkrV0 asset.GroupKeyRevealV0
-
-		err := gkrV0.Decode(r, buf, l)
-		if err != nil {
-			return fmt.Errorf("group key reveal V0 decode "+
-				"error: %w", err)
-		}
-
-		*typ = &gkrV0
-		return nil
-	}
-
-	// Attempt decoding with GroupKeyRevealV1.
-	var gkrV1 asset.GroupKeyRevealV1
-
-	err := gkrV1.Decode(r, buf, l)
-	if err != nil {
-		return fmt.Errorf("group key reveal V1 decode error: %w", err)
-	}
-
-	*typ = &gkrV1
-	return nil
-}

proof/records.go

@@ -389,7 +389,7 @@ func GroupKeyRevealRecord(reveal *asset.GroupKeyReveal) tlv.Record {
 		)
 	}
 	return tlv.MakeDynamicRecord(
-		GroupKeyRevealType, reveal, recordSize, GroupKeyRevealEncoder,
-		GroupKeyRevealDecoder,
+		GroupKeyRevealType, reveal, recordSize,
+		asset.GroupKeyRevealEncoder, asset.GroupKeyRevealDecoder,
 	)
 }