Merge pull request #292 from blinklabs-io/feat/ledger-multi-asset

feat: better handling of Mary MultiAsset value

Author: agaffney

cmd/block-fetch/main.go

@@ -98,7 +98,19 @@ func main() {
 			for _, output := range tx.Outputs() {
 				fmt.Printf("    Address: %x\n", output.Address())
 				fmt.Printf("    Amount: %d\n", output.Amount())
-				fmt.Printf("    Assets: %#v\n", output.Assets())
+				assets := output.Assets()
+				if assets != nil {
+					fmt.Printf("    Assets:\n")
+					for _, policyId := range assets.Policies() {
+						fmt.Printf("      Policy Id: %s\n", policyId)
+						fmt.Printf("      Policy assets:\n")
+						for _, assetName := range assets.Assets(policyId) {
+							fmt.Printf("        Asset name: %s\n", assetName)
+							fmt.Printf("        Amount: %d\n", assets.Asset(policyId, assetName))
+							fmt.Println("")
+						}
+					}
+				}
 				fmt.Println("")
 			}
 		}

ledger/alonzo.go

@@ -128,7 +128,7 @@ func (o AlonzoTransactionOutput) Amount() uint64 {
 	return o.OutputAmount.Amount
 }
 
-func (o AlonzoTransactionOutput) Assets() interface{} {
+func (o AlonzoTransactionOutput) Assets() *MultiAsset[uint64] {
 	return o.OutputAmount.Assets
 }
 

ledger/babbage.go

@@ -173,7 +173,7 @@ func (o BabbageTransactionOutput) Amount() uint64 {
 	return o.OutputAmount.Amount
 }
 
-func (o BabbageTransactionOutput) Assets() interface{} {
+func (o BabbageTransactionOutput) Assets() *MultiAsset[uint64] {
 	return o.OutputAmount.Assets
 }
 

ledger/common.go

@@ -0,0 +1,62 @@
+// Copyright 2023 Blink Labs, LLC.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package ledger
+
+import (
+	"github.com/blinklabs-io/gouroboros/cbor"
+)
+
+// MultiAsset represents a collection of policies, assets, and quantities. It's used for
+// TX outputs (uint64) and TX asset minting (int64 to allow for negative values for burning)
+type MultiAsset[T int64 | uint64] struct {
+	data map[Blake2b224]map[cbor.ByteString]T
+}
+
+func (m *MultiAsset[T]) UnmarshalCBOR(data []byte) error {
+	_, err := cbor.Decode(data, &(m.data))
+	return err
+}
+
+func (m *MultiAsset[T]) MarshalCBOR() ([]byte, error) {
+	return cbor.Encode(&(m.data))
+}
+
+func (m *MultiAsset[T]) Policies() []Blake2b224 {
+	var ret []Blake2b224
+	for policyId := range m.data {
+		ret = append(ret, policyId)
+	}
+	return ret
+}
+
+func (m *MultiAsset[T]) Assets(policyId Blake2b224) [][]byte {
+	assets, ok := m.data[policyId]
+	if !ok {
+		return nil
+	}
+	var ret [][]byte
+	for assetName := range assets {
+		ret = append(ret, assetName.Bytes())
+	}
+	return ret
+}
+
+func (m *MultiAsset[T]) Asset(policyId Blake2b224, assetName []byte) T {
+	policy, ok := m.data[policyId]
+	if !ok {
+		return 0
+	}
+	return policy[cbor.ByteString(assetName)]
+}

ledger/mary.go

@@ -80,8 +80,7 @@ func (h *MaryBlockHeader) Era() Era {
 type MaryTransactionBody struct {
 	AllegraTransactionBody
 	TxOutputs []MaryTransactionOutput `cbor:"1,keyasint,omitempty"`
-	// TODO: further parsing of this field
-	Mint cbor.Value `cbor:"9,keyasint,omitempty"`
+	Mint      MultiAsset[int64]       `cbor:"9,keyasint,omitempty"`
 }
 
 func (b *MaryTransactionBody) UnmarshalCBOR(cborData []byte) error {
@@ -117,14 +116,15 @@ func (o MaryTransactionOutput) Amount() uint64 {
 	return o.OutputAmount.Amount
 }
 
-func (o MaryTransactionOutput) Assets() interface{} {
+func (o MaryTransactionOutput) Assets() *MultiAsset[uint64] {
 	return o.OutputAmount.Assets
 }
 
 type MaryTransactionOutputValue struct {
 	cbor.StructAsArray
 	Amount uint64
-	Assets map[Blake2b224]map[cbor.ByteString]uint64
+	// We use a pointer here to allow it to be nil
+	Assets *MultiAsset[uint64]
 }
 
 func (v *MaryTransactionOutputValue) UnmarshalCBOR(data []byte) error {

ledger/mary_test.go

@@ -23,15 +23,15 @@ import (
 	"github.com/blinklabs-io/gouroboros/internal/test"
 )
 
-func createMaryTransactionOutputValueAssets(policyId []byte, assetName []byte, amount uint64) map[Blake2b224]map[cbor.ByteString]uint64 {
-	ret := map[Blake2b224]map[cbor.ByteString]uint64{}
+func createMaryTransactionOutputValueAssets(policyId []byte, assetName []byte, amount uint64) *MultiAsset[uint64] {
+	data := map[Blake2b224]map[cbor.ByteString]uint64{}
 	policyIdKey := Blake2b224{}
 	copy(policyIdKey[:], policyId)
 	assetKey := cbor.ByteString(assetName)
-	ret[policyIdKey] = map[cbor.ByteString]uint64{
+	data[policyIdKey] = map[cbor.ByteString]uint64{
 		assetKey: amount,
 	}
-	return ret
+	return &MultiAsset[uint64]{data: data}
 }
 
 func TestMaryTransactionOutputValueEncodeDecode(t *testing.T) {

ledger/shelley.go

@@ -193,7 +193,7 @@ func (o ShelleyTransactionOutput) Amount() uint64 {
 	return o.OutputAmount
 }
 
-func (o ShelleyTransactionOutput) Assets() interface{} {
+func (o ShelleyTransactionOutput) Assets() *MultiAsset[uint64] {
 	return nil
 }
 

ledger/tx.go

@@ -36,8 +36,7 @@ type TransactionInput interface {
 type TransactionOutput interface {
 	Address() []byte
 	Amount() uint64
-	// TODO: create more specific type/interface for assets
-	Assets() interface{}
+	Assets() *MultiAsset[uint64]
 }
 
 func NewTransactionFromCbor(txType uint, data []byte) (interface{}, error) {