feat: common interface for accessing TX witnesses (#899)

Fixes #664

Signed-off-by: Aurora Gaffney <[email protected]>

Author: agaffney

ledger/allegra/allegra.go

@@ -1,4 +1,4 @@
-// Copyright 2024 Blink Labs Software
+// Copyright 2025 Blink Labs Software
 //
 // Licensed under the Apache License, Version 2.0 (the "License");
 // you may not use this file except in compliance with the License.
@@ -290,6 +290,10 @@ func (t AllegraTransaction) ProtocolParameterUpdates() (uint64, map[common.Blake
 	return t.Body.ProtocolParameterUpdates()
 }
 
+func (t AllegraTransaction) Witnesses() common.TransactionWitnessSet {
+	return t.WitnessSet
+}
+
 func (t *AllegraTransaction) Cbor() []byte {
 	// Return stored CBOR if we have any
 	cborData := t.DecodeStoreCbor.Cbor()

ledger/alonzo/alonzo.go

@@ -1,4 +1,4 @@
-// Copyright 2024 Blink Labs Software
+// Copyright 2025 Blink Labs Software
 //
 // Licensed under the Apache License, Version 2.0 (the "License");
 // you may not use this file except in compliance with the License.
@@ -303,21 +303,54 @@ func (o AlonzoTransactionOutput) Utxorpc() *utxorpc.TxOutput {
 
 type AlonzoRedeemer struct {
 	cbor.StructAsArray
-	Tag     uint8
+	Tag     common.RedeemerTag
 	Index   uint32
-	Data    cbor.RawMessage
+	Data    cbor.LazyValue
 	ExUnits common.RedeemerExUnits
 }
 
+type AlonzoRedeemers []AlonzoRedeemer
+
+func (r AlonzoRedeemers) Indexes(tag common.RedeemerTag) []uint {
+	ret := []uint{}
+	for _, redeemer := range r {
+		if redeemer.Tag == tag {
+			ret = append(ret, uint(redeemer.Index))
+		}
+	}
+	return ret
+}
+
+func (r AlonzoRedeemers) Value(index uint, tag common.RedeemerTag) (cbor.LazyValue, common.RedeemerExUnits) {
+	for _, redeemer := range r {
+		if redeemer.Tag == tag && uint(redeemer.Index) == index {
+			return redeemer.Data, redeemer.ExUnits
+		}
+	}
+	return cbor.LazyValue{}, common.RedeemerExUnits{}
+}
+
 type AlonzoTransactionWitnessSet struct {
 	shelley.ShelleyTransactionWitnessSet
-	PlutusV1Scripts [][]byte         `cbor:"3,keyasint,omitempty"`
-	PlutusData      []cbor.Value     `cbor:"4,keyasint,omitempty"`
-	Redeemers       []AlonzoRedeemer `cbor:"5,keyasint,omitempty"`
+	WsPlutusV1Scripts [][]byte        `cbor:"3,keyasint,omitempty"`
+	WsPlutusData      []cbor.Value    `cbor:"4,keyasint,omitempty"`
+	WsRedeemers       AlonzoRedeemers `cbor:"5,keyasint,omitempty"`
+}
+
+func (w *AlonzoTransactionWitnessSet) UnmarshalCBOR(cborData []byte) error {
+	return w.UnmarshalCbor(cborData, w)
+}
+
+func (w AlonzoTransactionWitnessSet) PlutusV1Scripts() [][]byte {
+	return w.WsPlutusV1Scripts
 }
 
-func (t *AlonzoTransactionWitnessSet) UnmarshalCBOR(cborData []byte) error {
-	return t.UnmarshalCbor(cborData, t)
+func (w AlonzoTransactionWitnessSet) PlutusData() []cbor.Value {
+	return w.WsPlutusData
+}
+
+func (w AlonzoTransactionWitnessSet) Redeemers() common.TransactionWitnessRedeemers {
+	return w.WsRedeemers
 }
 
 type AlonzoTransaction struct {
@@ -452,6 +485,10 @@ func (t AlonzoTransaction) Produced() []common.Utxo {
 	}
 }
 
+func (t AlonzoTransaction) Witnesses() common.TransactionWitnessSet {
+	return t.WitnessSet
+}
+
 func (t *AlonzoTransaction) Cbor() []byte {
 	// Return stored CBOR if we have any
 	cborData := t.DecodeStoreCbor.Cbor()

ledger/babbage/babbage.go

@@ -1,4 +1,4 @@
-// Copyright 2024 Blink Labs Software
+// Copyright 2025 Blink Labs Software
 //
 // Licensed under the Apache License, Version 2.0 (the "License");
 // you may not use this file except in compliance with the License.
@@ -491,11 +491,15 @@ func (o BabbageTransactionOutput) Utxorpc() *utxorpc.TxOutput {
 
 type BabbageTransactionWitnessSet struct {
 	alonzo.AlonzoTransactionWitnessSet
-	PlutusV2Scripts [][]byte `cbor:"6,keyasint,omitempty"`
+	WsPlutusV2Scripts [][]byte `cbor:"6,keyasint,omitempty"`
 }
 
-func (t *BabbageTransactionWitnessSet) UnmarshalCBOR(cborData []byte) error {
-	return t.UnmarshalCbor(cborData, t)
+func (w *BabbageTransactionWitnessSet) UnmarshalCBOR(cborData []byte) error {
+	return w.UnmarshalCbor(cborData, w)
+}
+
+func (w BabbageTransactionWitnessSet) PlutusV2Scripts() [][]byte {
+	return w.WsPlutusV2Scripts
 }
 
 type BabbageTransaction struct {
@@ -637,6 +641,10 @@ func (t BabbageTransaction) Produced() []common.Utxo {
 	}
 }
 
+func (t BabbageTransaction) Witnesses() common.TransactionWitnessSet {
+	return t.WitnessSet
+}
+
 func (t *BabbageTransaction) Cbor() []byte {
 	// Return stored CBOR if we have any
 	cborData := t.DecodeStoreCbor.Cbor()

ledger/byron/byron.go

@@ -288,6 +288,11 @@ func (t *ByronTransaction) Produced() []common.Utxo {
 	return ret
 }
 
+func (t ByronTransaction) Witnesses() common.TransactionWitnessSet {
+	// TODO: implement once we properly support decoding Byron TX witnesses (#853)
+	return nil
+}
+
 func (t *ByronTransaction) Utxorpc() *utxorpc.Tx {
 	return &utxorpc.Tx{}
 }

ledger/common/tx.go

@@ -1,4 +1,4 @@
-// Copyright 2024 Blink Labs Software
+// Copyright 2025 Blink Labs Software
 //
 // Licensed under the Apache License, Version 2.0 (the "License");
 // you may not use this file except in compliance with the License.
@@ -28,6 +28,7 @@ type Transaction interface {
 	IsValid() bool
 	Consumed() []TransactionInput
 	Produced() []Utxo
+	Witnesses() TransactionWitnessSet
 }
 
 type TransactionBody interface {
@@ -73,6 +74,22 @@ type TransactionOutput interface {
 	Utxorpc() *utxorpc.TxOutput
 }
 
+type TransactionWitnessSet interface {
+	Vkey() []VkeyWitness
+	NativeScripts() []NativeScript
+	Bootstrap() []BootstrapWitness
+	PlutusData() []cbor.Value
+	PlutusV1Scripts() [][]byte
+	PlutusV2Scripts() [][]byte
+	PlutusV3Scripts() [][]byte
+	Redeemers() TransactionWitnessRedeemers
+}
+
+type TransactionWitnessRedeemers interface {
+	Indexes(RedeemerTag) []uint
+	Value(uint, RedeemerTag) (cbor.LazyValue, RedeemerExUnits)
+}
+
 type Utxo struct {
 	Id     TransactionInput
 	Output TransactionOutput

ledger/common/witness.go

@@ -18,6 +18,17 @@ import (
 	"github.com/blinklabs-io/gouroboros/cbor"
 )
 
+type RedeemerTag uint8
+
+const (
+	RedeemerTagSpend     RedeemerTag = 0
+	RedeemerTagMint      RedeemerTag = 1
+	RedeemerTagCert      RedeemerTag = 2
+	RedeemerTagReward    RedeemerTag = 3
+	RedeemerTagVoting    RedeemerTag = 4
+	RedeemerTagProposing RedeemerTag = 5
+)
+
 type VkeyWitness struct {
 	cbor.StructAsArray
 	Vkey      []byte

ledger/conway/conway.go

@@ -1,4 +1,4 @@
-// Copyright 2024 Blink Labs Software
+// Copyright 2025 Blink Labs Software
 //
 // Licensed under the Apache License, Version 2.0 (the "License");
 // you may not use this file except in compliance with the License.
@@ -149,13 +149,13 @@ func (h *ConwayBlockHeader) Era() common.Era {
 
 type ConwayRedeemerKey struct {
 	cbor.StructAsArray
-	Tag   uint8
+	Tag   common.RedeemerTag
 	Index uint32
 }
 
 type ConwayRedeemerValue struct {
 	cbor.StructAsArray
-	Data    cbor.RawMessage
+	Data    cbor.LazyValue
 	ExUnits common.RedeemerExUnits
 }
 
@@ -189,14 +189,43 @@ func (r *ConwayRedeemers) UnmarshalCBOR(cborData []byte) error {
 	return nil
 }
 
+func (r ConwayRedeemers) Indexes(tag common.RedeemerTag) []uint {
+	ret := []uint{}
+	for key := range r.Redeemers {
+		if key.Tag == tag {
+			ret = append(ret, uint(key.Index))
+		}
+	}
+	return ret
+}
+
+func (r ConwayRedeemers) Value(index uint, tag common.RedeemerTag) (cbor.LazyValue, common.RedeemerExUnits) {
+	redeemer, ok := r.Redeemers[ConwayRedeemerKey{
+		Tag:   tag,
+		Index: uint32(index),
+	}]
+	if ok {
+		return redeemer.Data, redeemer.ExUnits
+	}
+	return cbor.LazyValue{}, common.RedeemerExUnits{}
+}
+
 type ConwayTransactionWitnessSet struct {
 	babbage.BabbageTransactionWitnessSet
-	Redeemers       ConwayRedeemers `cbor:"5,keyasint,omitempty"`
-	PlutusV3Scripts [][]byte        `cbor:"7,keyasint,omitempty"`
+	WsRedeemers       ConwayRedeemers `cbor:"5,keyasint,omitempty"`
+	WsPlutusV3Scripts [][]byte        `cbor:"7,keyasint,omitempty"`
+}
+
+func (w *ConwayTransactionWitnessSet) UnmarshalCBOR(cborData []byte) error {
+	return w.UnmarshalCbor(cborData, w)
 }
 
-func (t *ConwayTransactionWitnessSet) UnmarshalCBOR(cborData []byte) error {
-	return t.UnmarshalCbor(cborData, t)
+func (w ConwayTransactionWitnessSet) PlutusV3Scripts() [][]byte {
+	return w.WsPlutusV3Scripts
+}
+
+func (w ConwayTransactionWitnessSet) Redeemers() common.TransactionWitnessRedeemers {
+	return w.WsRedeemers
 }
 
 type ConwayTransactionInputSet struct {
@@ -401,6 +430,10 @@ func (t ConwayTransaction) Produced() []common.Utxo {
 	}
 }
 
+func (t ConwayTransaction) Witnesses() common.TransactionWitnessSet {
+	return t.WitnessSet
+}
+
 func (t *ConwayTransaction) Cbor() []byte {
 	// Return stored CBOR if we have any
 	cborData := t.DecodeStoreCbor.Cbor()

ledger/mary/mary.go

@@ -1,4 +1,4 @@
-// Copyright 2024 Blink Labs Software
+// Copyright 2025 Blink Labs Software
 //
 // Licensed under the Apache License, Version 2.0 (the "License");
 // you may not use this file except in compliance with the License.
@@ -298,6 +298,10 @@ func (t MaryTransaction) Produced() []common.Utxo {
 	return ret
 }
 
+func (t MaryTransaction) Witnesses() common.TransactionWitnessSet {
+	return t.WitnessSet
+}
+
 func (t *MaryTransaction) Cbor() []byte {
 	// Return stored CBOR if we have any
 	cborData := t.DecodeStoreCbor.Cbor()

ledger/shelley/shelley.go

@@ -1,4 +1,4 @@
-// Copyright 2024 Blink Labs Software
+// Copyright 2025 Blink Labs Software
 //
 // Licensed under the Apache License, Version 2.0 (the "License");
 // you may not use this file except in compliance with the License.
@@ -469,14 +469,51 @@ func (o ShelleyTransactionOutput) Utxorpc() *utxorpc.TxOutput {
 type ShelleyTransactionWitnessSet struct {
 	cbor.DecodeStoreCbor
 	VkeyWitnesses      []common.VkeyWitness      `cbor:"0,keyasint,omitempty"`
-	NativeScripts      []common.NativeScript     `cbor:"1,keyasint,omitempty"`
+	WsNativeScripts    []common.NativeScript     `cbor:"1,keyasint,omitempty"`
 	BootstrapWitnesses []common.BootstrapWitness `cbor:"2,keyasint,omitempty"`
 }
 
 func (t *ShelleyTransactionWitnessSet) UnmarshalCBOR(cborData []byte) error {
 	return t.UnmarshalCbor(cborData, t)
 }
 
+func (w ShelleyTransactionWitnessSet) Vkey() []common.VkeyWitness {
+	return w.VkeyWitnesses
+}
+
+func (w ShelleyTransactionWitnessSet) Bootstrap() []common.BootstrapWitness {
+	return w.BootstrapWitnesses
+}
+
+func (w ShelleyTransactionWitnessSet) NativeScripts() []common.NativeScript {
+	return w.WsNativeScripts
+}
+
+func (w ShelleyTransactionWitnessSet) PlutusData() []cbor.Value {
+	// No plutus data in Shelley
+	return nil
+}
+
+func (w ShelleyTransactionWitnessSet) PlutusV1Scripts() [][]byte {
+	// No plutus v1 scripts in Shelley
+	return nil
+}
+
+func (w ShelleyTransactionWitnessSet) PlutusV2Scripts() [][]byte {
+	// No plutus v2 scripts in Shelley
+	return nil
+}
+
+func (w ShelleyTransactionWitnessSet) PlutusV3Scripts() [][]byte {
+	// No plutus v3 scripts in Shelley
+	return nil
+}
+
+func (w ShelleyTransactionWitnessSet) Redeemers() common.TransactionWitnessRedeemers {
+	// No redeemers in Shelley
+	return nil
+}
+
 type ShelleyTransaction struct {
 	cbor.StructAsArray
 	cbor.DecodeStoreCbor
@@ -595,6 +632,10 @@ func (t ShelleyTransaction) Produced() []common.Utxo {
 	return ret
 }
 
+func (t ShelleyTransaction) Witnesses() common.TransactionWitnessSet {
+	return t.WitnessSet
+}
+
 func (t ShelleyTransaction) Utxorpc() *utxorpc.Tx {
 	return t.Body.Utxorpc()
 }