internal/ethapi: prealloc map for the txpool api (#32110)

use `make(map, len(txpool))` to prealloc the map for the txpool content,
to avoid the map growing in the loop.

Author: nthumann

internal/ethapi/api.go

@@ -186,23 +186,23 @@ func NewTxPoolAPI(b Backend) *TxPoolAPI {
 
 // Content returns the transactions contained within the transaction pool.
 func (api *TxPoolAPI) Content() map[string]map[string]map[string]*RPCTransaction {
+	pending, queue := api.b.TxPoolContent()
 	content := map[string]map[string]map[string]*RPCTransaction{
-		"pending": make(map[string]map[string]*RPCTransaction),
-		"queued":  make(map[string]map[string]*RPCTransaction),
+		"pending": make(map[string]map[string]*RPCTransaction, len(pending)),
+		"queued":  make(map[string]map[string]*RPCTransaction, len(queue)),
 	}
-	pending, queue := api.b.TxPoolContent()
 	curHeader := api.b.CurrentHeader()
 	// Flatten the pending transactions
 	for account, txs := range pending {
-		dump := make(map[string]*RPCTransaction)
+		dump := make(map[string]*RPCTransaction, len(txs))
 		for _, tx := range txs {
 			dump[fmt.Sprintf("%d", tx.Nonce())] = NewRPCPendingTransaction(tx, curHeader, api.b.ChainConfig())
 		}
 		content["pending"][account.Hex()] = dump
 	}
 	// Flatten the queued transactions
 	for account, txs := range queue {
-		dump := make(map[string]*RPCTransaction)
+		dump := make(map[string]*RPCTransaction, len(txs))
 		for _, tx := range txs {
 			dump[fmt.Sprintf("%d", tx.Nonce())] = NewRPCPendingTransaction(tx, curHeader, api.b.ChainConfig())
 		}
@@ -246,11 +246,11 @@ func (api *TxPoolAPI) Status() map[string]hexutil.Uint {
 // Inspect retrieves the content of the transaction pool and flattens it into an
 // easily inspectable list.
 func (api *TxPoolAPI) Inspect() map[string]map[string]map[string]string {
+	pending, queue := api.b.TxPoolContent()
 	content := map[string]map[string]map[string]string{
-		"pending": make(map[string]map[string]string),
-		"queued":  make(map[string]map[string]string),
+		"pending": make(map[string]map[string]string, len(pending)),
+		"queued":  make(map[string]map[string]string, len(queue)),
 	}
-	pending, queue := api.b.TxPoolContent()
 
 	// Define a formatter to flatten a transaction into a string
 	format := func(tx *types.Transaction) string {
@@ -261,15 +261,15 @@ func (api *TxPoolAPI) Inspect() map[string]map[string]map[string]string {
 	}
 	// Flatten the pending transactions
 	for account, txs := range pending {
-		dump := make(map[string]string)
+		dump := make(map[string]string, len(txs))
 		for _, tx := range txs {
 			dump[fmt.Sprintf("%d", tx.Nonce())] = format(tx)
 		}
 		content["pending"][account.Hex()] = dump
 	}
 	// Flatten the queued transactions
 	for account, txs := range queue {
-		dump := make(map[string]string)
+		dump := make(map[string]string, len(txs))
 		for _, tx := range txs {
 			dump[fmt.Sprintf("%d", tx.Nonce())] = format(tx)
 		}