perf(ledger): preallocate tx input/output slices (#1253)

wolf31o2 · web-flow · commit 910b0da541ec · 2025-11-18T09:33:30.000-05:00
Also, use CBOR major type (map vs list) to determine transaction
processing path.

Signed-off-by: Chris Gianelloni &lt;wolf31o2@blinklabs.io&gt;
diff --git a/ledger/alonzo/alonzo.go b/ledger/alonzo/alonzo.go
@@ -233,17 +233,18 @@ func (b *AlonzoTransactionBody) UnmarshalCBOR(cborData []byte) error {
 }
 
 func (b *AlonzoTransactionBody) Inputs() []common.TransactionInput {
-	ret := []common.TransactionInput{}
-	for _, input := range b.TxInputs.Items() {
-		ret = append(ret, input)
+	items := b.TxInputs.Items()
+	ret := make([]common.TransactionInput, len(items))
+	for i, input := range items {
+		ret[i] = input
 	}
 	return ret
 }
 
 func (b *AlonzoTransactionBody) Outputs() []common.TransactionOutput {
-	ret := []common.TransactionOutput{}
-	for _, output := range b.TxOutputs {
-		ret = append(ret, &output)
+	ret := make([]common.TransactionOutput, len(b.TxOutputs))
+	for i := range b.TxOutputs {
+		ret[i] = &b.TxOutputs[i]
 	}
 	return ret
 }
@@ -292,9 +293,10 @@ func (b *AlonzoTransactionBody) AssetMint() *common.MultiAsset[common.MultiAsset
 }
 
 func (b *AlonzoTransactionBody) Collateral() []common.TransactionInput {
-	ret := []common.TransactionInput{}
-	for _, collateral := range b.TxCollateral.Items() {
-		ret = append(ret, collateral)
+	items := b.TxCollateral.Items()
+	ret := make([]common.TransactionInput, len(items))
+	for i, collateral := range items {
+		ret[i] = collateral
 	}
 	return ret
 }
diff --git a/ledger/babbage/babbage.go b/ledger/babbage/babbage.go
@@ -276,17 +276,18 @@ func (b *BabbageTransactionBody) Id() common.Blake2b256 {
 }
 
 func (b *BabbageTransactionBody) Inputs() []common.TransactionInput {
-	ret := []common.TransactionInput{}
-	for _, input := range b.TxInputs.Items() {
-		ret = append(ret, input)
+	items := b.TxInputs.Items()
+	ret := make([]common.TransactionInput, len(items))
+	for i, input := range items {
+		ret[i] = input
 	}
 	return ret
 }
 
 func (b *BabbageTransactionBody) Outputs() []common.TransactionOutput {
-	ret := []common.TransactionOutput{}
-	for _, output := range b.TxOutputs {
-		ret = append(ret, &output)
+	ret := make([]common.TransactionOutput, len(b.TxOutputs))
+	for i := range b.TxOutputs {
+		ret[i] = &b.TxOutputs[i]
 	}
 	return ret
 }
@@ -335,9 +336,10 @@ func (b *BabbageTransactionBody) AssetMint() *common.MultiAsset[common.MultiAsse
 }
 
 func (b *BabbageTransactionBody) Collateral() []common.TransactionInput {
-	ret := []common.TransactionInput{}
-	for _, collateral := range b.TxCollateral.Items() {
-		ret = append(ret, collateral)
+	items := b.TxCollateral.Items()
+	ret := make([]common.TransactionInput, len(items))
+	for i, collateral := range items {
+		ret[i] = collateral
 	}
 	return ret
 }
@@ -351,9 +353,10 @@ func (b *BabbageTransactionBody) ScriptDataHash() *common.Blake2b256 {
 }
 
 func (b *BabbageTransactionBody) ReferenceInputs() []common.TransactionInput {
-	ret := []common.TransactionInput{}
-	for _, input := range b.TxReferenceInputs.Items() {
-		ret = append(ret, &input)
+	items := b.TxReferenceInputs.Items()
+	ret := make([]common.TransactionInput, len(items))
+	for i := range items {
+		ret[i] = &items[i]
 	}
 	return ret
 }
diff --git a/ledger/shelley/shelley.go b/ledger/shelley/shelley.go
@@ -239,17 +239,18 @@ func (b *ShelleyTransactionBody) UnmarshalCBOR(cborData []byte) error {
 }
 
 func (b *ShelleyTransactionBody) Inputs() []common.TransactionInput {
-	ret := []common.TransactionInput{}
-	for _, input := range b.TxInputs.Items() {
-		ret = append(ret, input)
+	items := b.TxInputs.Items()
+	ret := make([]common.TransactionInput, len(items))
+	for i, input := range items {
+		ret[i] = input
 	}
 	return ret
 }
 
 func (b *ShelleyTransactionBody) Outputs() []common.TransactionOutput {
-	ret := []common.TransactionOutput{}
-	for _, output := range b.TxOutputs {
-		ret = append(ret, &output)
+	ret := make([]common.TransactionOutput, len(b.TxOutputs))
+	for i := range b.TxOutputs {
+		ret[i] = &b.TxOutputs[i]
 	}
 	return ret
 }
diff --git a/ledger/tx.go b/ledger/tx.go
@@ -80,46 +80,69 @@ func NewTransactionBodyFromCbor(
 // NewTransactionOutputFromCbor attempts to parse the provided arbitrary CBOR data as a transaction output from
 // each of the eras, returning the first one that we can successfully decode
 func NewTransactionOutputFromCbor(data []byte) (TransactionOutput, error) {
-	if txOut, err := NewByronTransactionOutputFromCbor(data); err == nil {
-		return txOut, nil
+	if len(data) == 0 {
+		return nil, errors.New("unknown transaction output type")
 	}
-	if txOut, err := NewShelleyTransactionOutputFromCbor(data); err == nil {
-		return txOut, nil
-	}
-	if txOut, err := NewMaryTransactionOutputFromCbor(data); err == nil {
-		return txOut, nil
-	}
-	if txOut, err := NewAlonzoTransactionOutputFromCbor(data); err == nil {
-		return txOut, nil
-	}
-	if txOut, err := NewBabbageTransactionOutputFromCbor(data); err == nil {
-		return txOut, nil
+	// Check CBOR major type: 4 = array (Byron, Shelley, Mary, Alonzo), 5 = map (Babbage+)
+	majorType := data[0] >> 5
+	switch majorType {
+	case 4:
+		// Try array-encoded outputs: Byron, Shelley, Mary, Alonzo
+		if txOut, err := NewByronTransactionOutputFromCbor(data); err == nil {
+			return txOut, nil
+		}
+		if txOut, err := NewShelleyTransactionOutputFromCbor(data); err == nil {
+			return txOut, nil
+		}
+		if txOut, err := NewMaryTransactionOutputFromCbor(data); err == nil {
+			return txOut, nil
+		}
+		if txOut, err := NewAlonzoTransactionOutputFromCbor(data); err == nil {
+			return txOut, nil
+		}
+	case 5:
+		// Try map-encoded outputs: Babbage+
+		if txOut, err := NewBabbageTransactionOutputFromCbor(data); err == nil {
+			return txOut, nil
+		}
 	}
 	return nil, errors.New("unknown transaction output type")
 }
 
 func DetermineTransactionType(data []byte) (uint, error) {
-	if _, err := NewByronTransactionFromCbor(data); err == nil {
-		return TxTypeByron, nil
-	}
-	if _, err := NewShelleyTransactionFromCbor(data); err == nil {
-		return TxTypeShelley, nil
-	}
-	if _, err := NewAllegraTransactionFromCbor(data); err == nil {
-		return TxTypeAllegra, nil
+	if len(data) == 0 {
+		return 0, errors.New("unknown transaction type")
 	}
-	if _, err := NewMaryTransactionFromCbor(data); err == nil {
-		return TxTypeMary, nil
-	}
-	if _, err := NewAlonzoTransactionFromCbor(data); err == nil {
-		return TxTypeAlonzo, nil
-	}
-	if _, err := NewBabbageTransactionFromCbor(data); err == nil {
-		return TxTypeBabbage, nil
-	}
-	if _, err := NewConwayTransactionFromCbor(data); err == nil {
-		return TxTypeConway, nil
+	// Fast path: check first byte to distinguish Byron from post-Shelley eras
+	firstByte := data[0]
+	switch firstByte {
+	case 0x83: // Byron, Shelley, Allegra, and Mary transactions are 3-element arrays
+		if _, err := NewByronTransactionFromCbor(data); err == nil {
+			return TxTypeByron, nil
+		}
+		if _, err := NewShelleyTransactionFromCbor(data); err == nil {
+			return TxTypeShelley, nil
+		}
+		if _, err := NewAllegraTransactionFromCbor(data); err == nil {
+			return TxTypeAllegra, nil
+		}
+		if _, err := NewMaryTransactionFromCbor(data); err == nil {
+			return TxTypeMary, nil
+		}
+	case 0x84: // Alonzo+ transactions are 4-element arrays
+		// Try most recent eras first for better performance
+		if _, err := NewConwayTransactionFromCbor(data); err == nil {
+			return TxTypeConway, nil
+		}
+		if _, err := NewBabbageTransactionFromCbor(data); err == nil {
+			return TxTypeBabbage, nil
+		}
+		if _, err := NewAlonzoTransactionFromCbor(data); err == nil {
+			return TxTypeAlonzo, nil
+		}
 	}
+
+	// Fallback: try Leios in case our assumptions are wrong
 	if _, err := NewLeiosTransactionFromCbor(data); err == nil {
 		return TxTypeLeios, nil
 	}
diff --git a/ledger/tx_test.go b/ledger/tx_test.go
@@ -1,4 +1,4 @@
-// Copyright 2023 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.
@@ -154,6 +154,9 @@ func BenchmarkTransactionSerialization_Byron(b *testing.B) {
 	if err != nil {
 		b.Fatal(err)
 	}
+	if tx == nil {
+		b.Fatal("tx is nil")
+	}
 	b.ResetTimer()
 	for i := 0; i < b.N; i++ {
 		_ = tx.Cbor()
@@ -177,6 +180,9 @@ func BenchmarkTransactionSerialization_Conway(b *testing.B) {
 	if err != nil {
 		b.Fatal(err)
 	}
+	if tx == nil {
+		b.Fatal("tx is nil")
+	}
 	b.ResetTimer()
 	for i := 0; i < b.N; i++ {
 		_ = tx.Cbor()

Original file line number	Diff line number	Diff line change
`@@ -233,17 +233,18 @@ func (b *AlonzoTransactionBody) UnmarshalCBOR(cborData []byte) error {`
`233`	`233`	`}`
`234`	`234`
`235`	`235`	`func (b *AlonzoTransactionBody) Inputs() []common.TransactionInput {`
`236`		`- ret := []common.TransactionInput{}`
`237`		`- for _, input := range b.TxInputs.Items() {`
`238`		`- ret = append(ret, input)`
	`236`	`+ items := b.TxInputs.Items()`
	`237`	`+ ret := make([]common.TransactionInput, len(items))`
	`238`	`+ for i, input := range items {`
	`239`	`+ ret[i] = input`
`239`	`240`	`}`
`240`	`241`	`return ret`
`241`	`242`	`}`
`242`	`243`
`243`	`244`	`func (b *AlonzoTransactionBody) Outputs() []common.TransactionOutput {`
`244`		`- ret := []common.TransactionOutput{}`
`245`		`- for _, output := range b.TxOutputs {`
`246`		`- ret = append(ret, &output)`
	`245`	`+ ret := make([]common.TransactionOutput, len(b.TxOutputs))`
	`246`	`+ for i := range b.TxOutputs {`
	`247`	`+ ret[i] = &b.TxOutputs[i]`
`247`	`248`	`}`
`248`	`249`	`return ret`
`249`	`250`	`}`
`@@ -292,9 +293,10 @@ func (b AlonzoTransactionBody) AssetMint() common.MultiAsset[common.MultiAsset`
`292`	`293`	`}`
`293`	`294`
`294`	`295`	`func (b *AlonzoTransactionBody) Collateral() []common.TransactionInput {`
`295`		`- ret := []common.TransactionInput{}`
`296`		`- for _, collateral := range b.TxCollateral.Items() {`
`297`		`- ret = append(ret, collateral)`
	`296`	`+ items := b.TxCollateral.Items()`
	`297`	`+ ret := make([]common.TransactionInput, len(items))`
	`298`	`+ for i, collateral := range items {`
	`299`	`+ ret[i] = collateral`
`298`	`300`	`}`
`299`	`301`	`return ret`
`300`	`302`	`}`
Original file line number	Diff line number	Diff line change
`@@ -276,17 +276,18 @@ func (b *BabbageTransactionBody) Id() common.Blake2b256 {`
`276`	`276`	`}`
`277`	`277`
`278`	`278`	`func (b *BabbageTransactionBody) Inputs() []common.TransactionInput {`
`279`		`- ret := []common.TransactionInput{}`
`280`		`- for _, input := range b.TxInputs.Items() {`
`281`		`- ret = append(ret, input)`
	`279`	`+ items := b.TxInputs.Items()`
	`280`	`+ ret := make([]common.TransactionInput, len(items))`
	`281`	`+ for i, input := range items {`
	`282`	`+ ret[i] = input`
`282`	`283`	`}`
`283`	`284`	`return ret`
`284`	`285`	`}`
`285`	`286`
`286`	`287`	`func (b *BabbageTransactionBody) Outputs() []common.TransactionOutput {`
`287`		`- ret := []common.TransactionOutput{}`
`288`		`- for _, output := range b.TxOutputs {`
`289`		`- ret = append(ret, &output)`
	`288`	`+ ret := make([]common.TransactionOutput, len(b.TxOutputs))`
	`289`	`+ for i := range b.TxOutputs {`
	`290`	`+ ret[i] = &b.TxOutputs[i]`
`290`	`291`	`}`
`291`	`292`	`return ret`
`292`	`293`	`}`
`@@ -335,9 +336,10 @@ func (b BabbageTransactionBody) AssetMint() common.MultiAsset[common.MultiAsse`
`335`	`336`	`}`
`336`	`337`
`337`	`338`	`func (b *BabbageTransactionBody) Collateral() []common.TransactionInput {`
`338`		`- ret := []common.TransactionInput{}`
`339`		`- for _, collateral := range b.TxCollateral.Items() {`
`340`		`- ret = append(ret, collateral)`
	`339`	`+ items := b.TxCollateral.Items()`
	`340`	`+ ret := make([]common.TransactionInput, len(items))`
	`341`	`+ for i, collateral := range items {`
	`342`	`+ ret[i] = collateral`
`341`	`343`	`}`
`342`	`344`	`return ret`
`343`	`345`	`}`
`@@ -351,9 +353,10 @@ func (b BabbageTransactionBody) ScriptDataHash() common.Blake2b256 {`
`351`	`353`	`}`
`352`	`354`
`353`	`355`	`func (b *BabbageTransactionBody) ReferenceInputs() []common.TransactionInput {`
`354`		`- ret := []common.TransactionInput{}`
`355`		`- for _, input := range b.TxReferenceInputs.Items() {`
`356`		`- ret = append(ret, &input)`
	`356`	`+ items := b.TxReferenceInputs.Items()`
	`357`	`+ ret := make([]common.TransactionInput, len(items))`
	`358`	`+ for i := range items {`
	`359`	`+ ret[i] = &items[i]`
`357`	`360`	`}`
`358`	`361`	`return ret`
`359`	`362`	`}`
Original file line number	Diff line number	Diff line change
`@@ -239,17 +239,18 @@ func (b *ShelleyTransactionBody) UnmarshalCBOR(cborData []byte) error {`
`239`	`239`	`}`
`240`	`240`
`241`	`241`	`func (b *ShelleyTransactionBody) Inputs() []common.TransactionInput {`
`242`		`- ret := []common.TransactionInput{}`
`243`		`- for _, input := range b.TxInputs.Items() {`
`244`		`- ret = append(ret, input)`
	`242`	`+ items := b.TxInputs.Items()`
	`243`	`+ ret := make([]common.TransactionInput, len(items))`
	`244`	`+ for i, input := range items {`
	`245`	`+ ret[i] = input`
`245`	`246`	`}`
`246`	`247`	`return ret`
`247`	`248`	`}`
`248`	`249`
`249`	`250`	`func (b *ShelleyTransactionBody) Outputs() []common.TransactionOutput {`
`250`		`- ret := []common.TransactionOutput{}`
`251`		`- for _, output := range b.TxOutputs {`
`252`		`- ret = append(ret, &output)`
	`251`	`+ ret := make([]common.TransactionOutput, len(b.TxOutputs))`
	`252`	`+ for i := range b.TxOutputs {`
	`253`	`+ ret[i] = &b.TxOutputs[i]`
`253`	`254`	`}`
`254`	`255`	`return ret`
`255`	`256`	`}`