From 0518efb4c39cd62fbc67f60037ac22a63932eed2 Mon Sep 17 00:00:00 2001
From: rian <rian.hughes@physics.ox.ac.uk>
Date: Thu, 19 Dec 2024 16:44:17 +0200
Subject: [PATCH] some heap optimisations

---
 mempool/mempool.go | 41 +++++++++--------------------------------
 1 file changed, 9 insertions(+), 32 deletions(-)

diff --git a/mempool/mempool.go b/mempool/mempool.go
index 6367fb0fb1..04d5fcca3e 100644
--- a/mempool/mempool.go
+++ b/mempool/mempool.go
@@ -3,7 +3,6 @@ package mempool
 import (
 	"encoding/binary"
 	"errors"
-	"fmt"
 
 	"github.com/NethermindEth/juno/core"
 	"github.com/NethermindEth/juno/core/felt"
@@ -51,22 +50,6 @@ func (p *Pool) WithValidator(validator ValidatorFunc) *Pool {
 	return p
 }
 
-func (p *Pool) rejectDuplicateTxn(userTxn *BroadcastedTransaction) error {
-	txHash := userTxn.Transaction.Hash().Marshal()
-	err := p.db.View(func(txn db.Transaction) error {
-		return txn.Get(txHash, func(val []byte) error {
-			if val != nil {
-				return fmt.Errorf("transaction already exists in the mempool: %x", txHash)
-			}
-			return nil
-		})
-	})
-	if errors.Is(err, db.ErrKeyNotFound) {
-		return nil
-	}
-	return err
-}
-
 // Push queues a transaction to the pool
 func (p *Pool) Push(userTxn *BroadcastedTransaction) error {
 	err := p.validator(userTxn)
@@ -74,13 +57,9 @@ func (p *Pool) Push(userTxn *BroadcastedTransaction) error {
 		return err
 	}
 
-	err = p.rejectDuplicateTxn(userTxn)
-	if err != nil {
-		return err
-	}
-
 	if err := p.db.Update(func(txn db.Transaction) error {
-		tail, err := p.tailHash(txn)
+		var tail *felt.Felt
+		tail, err := p.tailHash(txn, tail)
 		if err != nil && !errors.Is(err, db.ErrKeyNotFound) {
 			return err
 		}
@@ -90,7 +69,6 @@ func (p *Pool) Push(userTxn *BroadcastedTransaction) error {
 		}); err != nil {
 			return err
 		}
-		fmt.Println("tail", tail)
 		if tail != nil {
 			var oldTail storageElem
 			oldTail, err = p.elem(txn, tail)
@@ -135,7 +113,8 @@ func (p *Pool) Push(userTxn *BroadcastedTransaction) error {
 func (p *Pool) Pop() (BroadcastedTransaction, error) {
 	var nextTxn BroadcastedTransaction
 	return nextTxn, p.db.Update(func(txn db.Transaction) error {
-		headHash, err := p.headHash(txn)
+		var headHash *felt.Felt
+		headHash, err := p.headHash(txn, headHash)
 		if err != nil {
 			return err
 		}
@@ -212,10 +191,9 @@ func (p *Pool) updateLen(txn db.Transaction, l uint64) error {
 	return txn.Set([]byte(poolLengthKey), binary.BigEndian.AppendUint64(nil, l))
 }
 
-func (p *Pool) headHash(txn db.Transaction) (*felt.Felt, error) {
-	var head *felt.Felt
-	return head, txn.Get([]byte(headKey), func(b []byte) error {
-		head = new(felt.Felt).SetBytes(b)
+func (p *Pool) headHash(txn db.Transaction, headHash *felt.Felt) (*felt.Felt, error) {
+	return headHash, txn.Get([]byte(headKey), func(b []byte) error {
+		headHash = headHash.SetBytes(b)
 		return nil
 	})
 }
@@ -224,10 +202,9 @@ func (p *Pool) updateHead(txn db.Transaction, head *felt.Felt) error {
 	return txn.Set([]byte(headKey), head.Marshal())
 }
 
-func (p *Pool) tailHash(txn db.Transaction) (*felt.Felt, error) {
-	var tail *felt.Felt
+func (p *Pool) tailHash(txn db.Transaction, tail *felt.Felt) (*felt.Felt, error) {
 	return tail, txn.Get([]byte(tailKey), func(b []byte) error {
-		tail = new(felt.Felt).SetBytes(b)
+		tail = tail.SetBytes(b)
 		return nil
 	})
 }