feat: TX staking withdrawals support (#623)

This adds support for decoding and retrieving staking withdrawals from a TX

Fixes #332

ledger/allegra.go

@@ -174,6 +174,10 @@ func (t AllegraTransaction) Certificates() []Certificate {
 	return t.Body.Certificates()
 }
 
+func (t AllegraTransaction) Withdrawals() map[*Address]uint64 {
+	return t.Body.Withdrawals()
+}
+
 func (t AllegraTransaction) Metadata() *cbor.Value {
 	return t.TxMetadata
 }

ledger/alonzo.go

@@ -284,6 +284,10 @@ func (t AlonzoTransaction) Certificates() []Certificate {
 	return t.Body.Certificates()
 }
 
+func (t AlonzoTransaction) Withdrawals() map[*Address]uint64 {
+	return t.Body.Withdrawals()
+}
+
 func (t AlonzoTransaction) Metadata() *cbor.Value {
 	return t.TxMetadata
 }

ledger/babbage.go

@@ -460,6 +460,10 @@ func (t BabbageTransaction) Certificates() []Certificate {
 	return t.Body.Certificates()
 }
 
+func (t BabbageTransaction) Withdrawals() map[*Address]uint64 {
+	return t.Body.Withdrawals()
+}
+
 func (t BabbageTransaction) Metadata() *cbor.Value {
 	return t.TxMetadata
 }

ledger/byron.go

@@ -195,6 +195,11 @@ func (t *ByronTransaction) Certificates() []Certificate {
 	return nil
 }
 
+func (t *ByronTransaction) Withdrawals() map[*Address]uint64 {
+	// No withdrawals in Byron
+	return nil
+}
+
 func (t *ByronTransaction) Metadata() *cbor.Value {
 	return t.Attributes
 }

ledger/conway.go

@@ -180,6 +180,10 @@ func (t ConwayTransaction) Certificates() []Certificate {
 	return t.Body.Certificates()
 }
 
+func (t ConwayTransaction) Withdrawals() map[*Address]uint64 {
+	return t.Body.Withdrawals()
+}
+
 func (t ConwayTransaction) Metadata() *cbor.Value {
 	return t.TxMetadata
 }

ledger/mary.go

@@ -191,6 +191,10 @@ func (t MaryTransaction) Certificates() []Certificate {
 	return t.Body.Certificates()
 }
 
+func (t MaryTransaction) Withdrawals() map[*Address]uint64 {
+	return t.Body.Withdrawals()
+}
+
 func (t MaryTransaction) Metadata() *cbor.Value {
 	return t.TxMetadata
 }

ledger/shelley.go

@@ -168,11 +168,8 @@ type ShelleyTransactionBody struct {
 	TxFee          uint64                     `cbor:"2,keyasint,omitempty"`
 	Ttl            uint64                     `cbor:"3,keyasint,omitempty"`
 	TxCertificates []CertificateWrapper       `cbor:"4,keyasint,omitempty"`
-	// TODO: figure out how to parse this correctly
-	// We keep the raw CBOR because it can contain a map with []byte keys, which
-	// Go does not allow
-	Withdrawals cbor.Value `cbor:"5,keyasint,omitempty"`
-	Update      struct {
+	TxWithdrawals  map[*Address]uint64        `cbor:"5,keyasint,omitempty"`
+	Update         struct {
 		cbor.StructAsArray
 		ProtocolParamUpdates map[Blake2b224]ShelleyProtocolParameterUpdate
 		Epoch                uint64
@@ -243,6 +240,10 @@ func (b *ShelleyTransactionBody) Certificates() []Certificate {
 	return ret
 }
 
+func (b *ShelleyTransactionBody) Withdrawals() map[*Address]uint64 {
+	return b.TxWithdrawals
+}
+
 func (b *ShelleyTransactionBody) Utxorpc() *utxorpc.Tx {
 	var txi []*utxorpc.TxInput
 	var txo []*utxorpc.TxOutput
@@ -397,6 +398,10 @@ func (t ShelleyTransaction) Certificates() []Certificate {
 	return t.Body.Certificates()
 }
 
+func (t ShelleyTransaction) Withdrawals() map[*Address]uint64 {
+	return t.Body.Withdrawals()
+}
+
 func (t ShelleyTransaction) Metadata() *cbor.Value {
 	return t.TxMetadata
 }

ledger/tx.go

@@ -45,6 +45,7 @@ type TransactionBody interface {
 	CollateralReturn() TransactionOutput
 	TotalCollateral() uint64
 	Certificates() []Certificate
+	Withdrawals() map[*Address]uint64
 	Utxorpc() *utxorpc.Tx
 }