feat: TX validity interval start attribute (#633)

This adds a method for retrieving the validity interval start from a TX

Fixes #335

ledger/allegra.go

@@ -119,13 +119,17 @@ type AllegraTransactionBody struct {
 		ProtocolParamUpdates map[Blake2b224]AllegraProtocolParameterUpdate
 		Epoch                uint64
 	} `cbor:"6,keyasint,omitempty"`
-	ValidityIntervalStart uint64 `cbor:"8,keyasint,omitempty"`
+	TxValidityIntervalStart uint64 `cbor:"8,keyasint,omitempty"`
 }
 
 func (b *AllegraTransactionBody) UnmarshalCBOR(cborData []byte) error {
 	return b.UnmarshalCbor(cborData, b)
 }
 
+func (b *AllegraTransactionBody) ValidityIntervalStart() uint64 {
+	return b.TxValidityIntervalStart
+}
+
 type AllegraTransaction struct {
 	cbor.StructAsArray
 	cbor.DecodeStoreCbor
@@ -154,6 +158,10 @@ func (t AllegraTransaction) TTL() uint64 {
 	return t.Body.TTL()
 }
 
+func (t AllegraTransaction) ValidityIntervalStart() uint64 {
+	return t.Body.ValidityIntervalStart()
+}
+
 func (t AllegraTransaction) ReferenceInputs() []TransactionInput {
 	return t.Body.ReferenceInputs()
 }

ledger/alonzo.go

@@ -272,6 +272,10 @@ func (t AlonzoTransaction) TTL() uint64 {
 	return t.Body.TTL()
 }
 
+func (t AlonzoTransaction) ValidityIntervalStart() uint64 {
+	return t.Body.ValidityIntervalStart()
+}
+
 func (t AlonzoTransaction) ReferenceInputs() []TransactionInput {
 	return t.Body.ReferenceInputs()
 }

ledger/babbage.go

@@ -440,6 +440,10 @@ func (t BabbageTransaction) TTL() uint64 {
 	return t.Body.TTL()
 }
 
+func (t BabbageTransaction) ValidityIntervalStart() uint64 {
+	return t.Body.ValidityIntervalStart()
+}
+
 func (t BabbageTransaction) ReferenceInputs() []TransactionInput {
 	return t.Body.ReferenceInputs()
 }

ledger/byron.go

@@ -170,6 +170,11 @@ func (t *ByronTransaction) TTL() uint64 {
 	return 0
 }
 
+func (t *ByronTransaction) ValidityIntervalStart() uint64 {
+	// No validity interval start in Byron
+	return 0
+}
+
 func (t *ByronTransaction) ReferenceInputs() []TransactionInput {
 	// No reference inputs in Byron
 	return nil

ledger/conway.go

@@ -345,6 +345,10 @@ func (t ConwayTransaction) TTL() uint64 {
 	return t.Body.TTL()
 }
 
+func (t ConwayTransaction) ValidityIntervalStart() uint64 {
+	return t.Body.ValidityIntervalStart()
+}
+
 func (t ConwayTransaction) ReferenceInputs() []TransactionInput {
 	return t.Body.ReferenceInputs()
 }

ledger/mary.go

@@ -175,6 +175,10 @@ func (t MaryTransaction) TTL() uint64 {
 	return t.Body.TTL()
 }
 
+func (t MaryTransaction) ValidityIntervalStart() uint64 {
+	return t.Body.ValidityIntervalStart()
+}
+
 func (t MaryTransaction) ReferenceInputs() []TransactionInput {
 	return t.Body.ReferenceInputs()
 }

ledger/shelley.go

@@ -213,6 +213,11 @@ func (b *ShelleyTransactionBody) TTL() uint64 {
 	return b.Ttl
 }
 
+func (b *ShelleyTransactionBody) ValidityIntervalStart() uint64 {
+	// No validity interval start in Shelley
+	return 0
+}
+
 func (b *ShelleyTransactionBody) ReferenceInputs() []TransactionInput {
 	return []TransactionInput{}
 }
@@ -403,6 +408,10 @@ func (t ShelleyTransaction) TTL() uint64 {
 	return t.Body.TTL()
 }
 
+func (t ShelleyTransaction) ValidityIntervalStart() uint64 {
+	return t.Body.ValidityIntervalStart()
+}
+
 func (t ShelleyTransaction) ReferenceInputs() []TransactionInput {
 	return t.Body.ReferenceInputs()
 }

ledger/tx.go

@@ -40,6 +40,7 @@ type TransactionBody interface {
 	Inputs() []TransactionInput
 	Outputs() []TransactionOutput
 	TTL() uint64
+	ValidityIntervalStart() uint64
 	ReferenceInputs() []TransactionInput
 	Collateral() []TransactionInput
 	CollateralReturn() TransactionOutput