feat: TX donation attribute (#642)

This adds a method to retrieve the donation attribute from a TX

Fixes #627

README.md

@@ -135,7 +135,7 @@ This is not an exhaustive list of existing and planned features, but it covers t
     - [X] Voting procedures
     - [X] Proposal procedures
     - [X] Current treasury value
-    - [ ] Donation
+    - [X] Donation
 - [ ] Testing
   - [X] Test framework for mocking Ouroboros conversations
   - [ ] CBOR deserialization and serialization

ledger/allegra.go

@@ -214,6 +214,10 @@ func (t AllegraTransaction) CurrentTreasuryValue() int64 {
 	return t.Body.CurrentTreasuryValue()
 }
 
+func (t AllegraTransaction) Donation() uint64 {
+	return t.Body.Donation()
+}
+
 func (t AllegraTransaction) Metadata() *cbor.LazyValue {
 	return t.TxMetadata
 }

ledger/alonzo.go

@@ -328,6 +328,10 @@ func (t AlonzoTransaction) CurrentTreasuryValue() int64 {
 	return t.Body.CurrentTreasuryValue()
 }
 
+func (t AlonzoTransaction) Donation() uint64 {
+	return t.Body.Donation()
+}
+
 func (t AlonzoTransaction) Metadata() *cbor.LazyValue {
 	return t.TxMetadata
 }

ledger/babbage.go

@@ -496,6 +496,10 @@ func (t BabbageTransaction) CurrentTreasuryValue() int64 {
 	return t.Body.CurrentTreasuryValue()
 }
 
+func (t BabbageTransaction) Donation() uint64 {
+	return t.Body.Donation()
+}
+
 func (t BabbageTransaction) Metadata() *cbor.LazyValue {
 	return t.TxMetadata
 }

ledger/byron.go

@@ -240,6 +240,11 @@ func (t *ByronTransaction) CurrentTreasuryValue() int64 {
 	return 0
 }
 
+func (t *ByronTransaction) Donation() uint64 {
+	// No donation in Byron
+	return 0
+}
+
 func (t *ByronTransaction) Metadata() *cbor.LazyValue {
 	return t.Attributes
 }

ledger/conway.go

@@ -124,7 +124,7 @@ type ConwayTransactionBody struct {
 	TxVotingProcedures     VotingProcedures    `cbor:"19,keyasint,omitempty"`
 	TxProposalProcedures   []ProposalProcedure `cbor:"20,keyasint,omitempty"`
 	TxCurrentTreasuryValue int64               `cbor:"21,keyasint,omitempty"`
-	Donation               uint64              `cbor:"22,keyasint,omitempty"`
+	TxDonation             uint64              `cbor:"22,keyasint,omitempty"`
 }
 
 func (b *ConwayTransactionBody) UnmarshalCBOR(cborData []byte) error {
@@ -143,6 +143,10 @@ func (b *ConwayTransactionBody) CurrentTreasuryValue() int64 {
 	return b.TxCurrentTreasuryValue
 }
 
+func (b *ConwayTransactionBody) Donation() uint64 {
+	return b.TxDonation
+}
+
 // VotingProcedures is a convenience type to avoid needing to duplicate the full type definition everywhere
 type VotingProcedures map[*Voter]map[*GovActionId]VotingProcedure
 
@@ -405,6 +409,10 @@ func (t ConwayTransaction) CurrentTreasuryValue() int64 {
 	return t.Body.CurrentTreasuryValue()
 }
 
+func (t ConwayTransaction) Donation() uint64 {
+	return t.Body.Donation()
+}
+
 func (t ConwayTransaction) Metadata() *cbor.LazyValue {
 	return t.TxMetadata
 }

ledger/mary.go

@@ -231,6 +231,10 @@ func (t MaryTransaction) CurrentTreasuryValue() int64 {
 	return t.Body.CurrentTreasuryValue()
 }
 
+func (t MaryTransaction) Donation() uint64 {
+	return t.Body.Donation()
+}
+
 func (t MaryTransaction) Metadata() *cbor.LazyValue {
 	return t.TxMetadata
 }

ledger/shelley.go

@@ -283,6 +283,11 @@ func (b *ShelleyTransactionBody) CurrentTreasuryValue() int64 {
 	return 0
 }
 
+func (b *ShelleyTransactionBody) Donation() uint64 {
+	// No donation in Shelley
+	return 0
+}
+
 func (b *ShelleyTransactionBody) Utxorpc() *utxorpc.Tx {
 	var txi []*utxorpc.TxInput
 	var txo []*utxorpc.TxOutput
@@ -473,6 +478,10 @@ func (t ShelleyTransaction) CurrentTreasuryValue() int64 {
 	return t.Body.CurrentTreasuryValue()
 }
 
+func (t ShelleyTransaction) Donation() uint64 {
+	return t.Body.Donation()
+}
+
 func (t ShelleyTransaction) Metadata() *cbor.LazyValue {
 	return t.TxMetadata
 }

ledger/tx.go

@@ -54,6 +54,7 @@ type TransactionBody interface {
 	VotingProcedures() VotingProcedures
 	ProposalProcedures() []ProposalProcedure
 	CurrentTreasuryValue() int64
+	Donation() uint64
 	Utxorpc() *utxorpc.Tx
 }