Karthik/p23 sac event support (#5710)

* initial commit for sac event parsing

* break out code for parsing SAC v3 and v4

* Add unit tests for all stellar asset contract parsing

* Update horizon processors code and unit tests to read from the new horizon/internal/support/contractevents package

* Initial change to separate V3 events into their own function

* Rework the receiver function GetDiagnosticEvents on TransactionMeta to NOT return an error

* Rework diagnostic events completely. WIll fix failing tests later

* Unit tests for the new events functions

* Fix unit test fixtures to account for changes in getXXXEvents functionality in horizon and processors/

* make destinationMemo public

* Address code review comments

Author: karthikiyer56

ingest/ledger_transaction.go

@@ -31,6 +31,12 @@ type LedgerTransaction struct {
 	Hash          xdr.Hash
 }
 
+type TransactionEvents struct {
+	TransactionEvents []xdr.TransactionEvent
+	OperationEvents   [][]xdr.ContractEvent
+	DiagnosticEvents  []xdr.DiagnosticEvent
+}
+
 func (t *LedgerTransaction) txInternalError() bool {
 	return t.Result.Result.Result.Code == xdr.TransactionResultCodeTxInternalError
 }
@@ -236,15 +242,76 @@ func (t *LedgerTransaction) operationChanges(ops operationsMeta, index uint32) [
 	return changes
 }
 
+func (t *LedgerTransaction) GetContractEventsForOperation(opIndex uint32) ([]xdr.ContractEvent, error) {
+	return t.UnsafeMeta.GetContractEventsForOperation(opIndex)
+}
+
+// GetContractEvents returns a []xdr.ContractEvent for pnly smart contract transaction.
+// If it is not a smart contract transaction, it throws an error
+// For getting events from classic operations/transaction, use GetContractEventsForOperation
+// For getting soroban smart contract events,we rely on the fact that there will only be one operation present in the transaction
 func (t *LedgerTransaction) GetContractEvents() ([]xdr.ContractEvent, error) {
-	return t.UnsafeMeta.GetContractEvents()
+	if !t.IsSorobanTx() {
+		return nil, errors.New("not a soroban transaction")
+	}
+	return t.GetContractEventsForOperation(0)
 }
 
-// GetDiagnosticEvents returns all contract events emitted by a given operation.
+// GetDiagnosticEvents returns strictly diagnostic events emitted by a given transaction.
+// Please note that, depending on the configuration with which txMeta may be generated,
+// it is possible that, for smart contract transactions, the list of generated diagnostic events MAY include contract events as well
+// Users of this function (horizon, rpc, etc) should be careful not to double count diagnostic events and contract events in that case
 func (t *LedgerTransaction) GetDiagnosticEvents() ([]xdr.DiagnosticEvent, error) {
 	return t.UnsafeMeta.GetDiagnosticEvents()
 }
 
+// GetTransactionEvents gives the breakdown of xdr.ContractEvent, xdr.TransactionEvent, xdr.Disgnostic event as they appea in the TxMeta
+// In TransactionMetaV3, for soroban transactions, contract events and diagnostic events appear in the SorobanMeta struct in TransactionMetaV3, i.e. at the transaction level
+// In TransactionMetaV4 and onwards, there is a more granular breakdown, because of CAP-67 unified events
+//   - Classic operations will also have contract events.
+//   - Contract events will now be present in the "operation []OperationMetaV2" in the TransactionMetaV4 structure, instead of at the transaction level as in TxMetaV3.
+//     This is true for soroban transactions as well, which will only have one operation and thus contract events will appear at index 0 in the []OperationMetaV2 structure
+//   - Additionally, if its a soroban  transaction, the diagnostic events will also be included in the "DiagnosticEvents []DiagnosticEvent" structure
+//   - Non soroban transactions will have an empty list for DiagnosticEvents
+//
+// It is preferred to use this function in horizon and rpc
+func (t *LedgerTransaction) GetTransactionEvents() (TransactionEvents, error) {
+	txEvents := TransactionEvents{}
+	switch t.UnsafeMeta.V {
+	case 1, 2:
+		return txEvents, nil
+	case 3:
+		// There wont be any events for classic operations in TxMetaV3
+		if !t.IsSorobanTx() {
+			return txEvents, nil
+		}
+		contractEvents, err := t.GetContractEvents()
+		if err != nil {
+			return txEvents, err
+		}
+		diagnosticEvents, err := t.GetDiagnosticEvents()
+		if err != nil {
+			return txEvents, err
+		}
+		// There  will only ever be 1 smart contract operation per tx.
+		txEvents.OperationEvents = make([][]xdr.ContractEvent, 1)
+		txEvents.OperationEvents[0] = contractEvents
+		txEvents.DiagnosticEvents = diagnosticEvents
+	case 4:
+		txMeta := t.UnsafeMeta.MustV4()
+		txEvents.TransactionEvents = txMeta.Events
+		txEvents.DiagnosticEvents = txMeta.DiagnosticEvents
+		txEvents.OperationEvents = make([][]xdr.ContractEvent, len(txMeta.Operations))
+		for i, op := range txMeta.Operations {
+			txEvents.OperationEvents[i] = op.Events
+		}
+	default:
+		return txEvents, fmt.Errorf("unsupported TransactionMeta version: %v", t.UnsafeMeta.V)
+	}
+	return txEvents, nil
+
+}
+
 func (t *LedgerTransaction) ID() int64 {
 	return toid.New(int32(t.Ledger.LedgerSequence()), int32(t.Index), 0).ToInt64()
 }