fix: replace time.After with time.NewTimer and time.NewTicker for improved timer handling to avoid memory leaks

Author: iw4p

ton/transactions.go

@@ -5,12 +5,13 @@ import (
 	"context"
 	"errors"
 	"fmt"
+	"strings"
+	"time"
+
 	"github.com/xssnick/tonutils-go/address"
 	"github.com/xssnick/tonutils-go/tl"
 	"github.com/xssnick/tonutils-go/tlb"
 	"github.com/xssnick/tonutils-go/tvm/cell"
-	"strings"
-	"time"
 )
 
 func init() {
@@ -176,52 +177,60 @@ func (c *APIClient) GetTransaction(ctx context.Context, block *BlockIDExt, addr
 }
 
 func (c *APIClient) SubscribeOnTransactions(workerCtx context.Context, addr *address.Address, lastProcessedLT uint64, channel chan<- *tlb.Transaction) {
-	defer func() {
-		close(channel)
-	}()
+	defer close(channel)
 
 	wait := 0 * time.Second
+	timer := time.NewTimer(wait)
+	defer timer.Stop()
+
 	for {
 		select {
 		case <-workerCtx.Done():
 			return
-		case <-time.After(wait):
+		case <-timer.C:
 		}
 		wait = 3 * time.Second
 
 		ctx, cancel := context.WithTimeout(workerCtx, 10*time.Second)
 		master, err := c.CurrentMasterchainInfo(ctx)
 		cancel()
 		if err != nil {
+			timer.Reset(wait)
 			continue
 		}
 
 		ctx, cancel = context.WithTimeout(workerCtx, 10*time.Second)
 		acc, err := c.GetAccount(ctx, master, addr)
 		cancel()
 		if err != nil {
+			timer.Reset(wait)
 			continue
 		}
 		if !acc.IsActive || acc.LastTxLT == 0 {
 			// no transactions
+			timer.Reset(wait)
 			continue
 		}
 
 		if lastProcessedLT == acc.LastTxLT {
 			// already processed all
+			timer.Reset(wait)
 			continue
 		}
 
 		var transactions []*tlb.Transaction
 		lastHash, lastLT := acc.LastTxHash, acc.LastTxLT
 
 		waitList := 0 * time.Second
+		listTimer := time.NewTimer(waitList)
+
 	list:
 		for {
 			select {
 			case <-workerCtx.Done():
+				listTimer.Stop()
 				return
-			case <-time.After(waitList):
+			case <-listTimer.C:
 			}
 
 			ctx, cancel = context.WithTimeout(workerCtx, 10*time.Second)
@@ -230,9 +239,11 @@ func (c *APIClient) SubscribeOnTransactions(workerCtx context.Context, addr *add
 			if err != nil {
 				if lsErr, ok := err.(LSError); ok && lsErr.Code == -400 {
 					// lt not in db error
+					listTimer.Stop()
 					return
 				}
 				waitList = 3 * time.Second
+				listTimer.Reset(waitList)
 				continue
 			}
 
@@ -255,8 +266,11 @@ func (c *APIClient) SubscribeOnTransactions(workerCtx context.Context, addr *add
 			lastLT, lastHash = res[len(res)-1].PrevTxLT, res[len(res)-1].PrevTxHash
 			transactions = append(transactions, res...)
 			waitList = 0 * time.Second
+			listTimer.Reset(waitList)
 		}
 
+		listTimer.Stop()
+
 		if len(transactions) > 0 {
 			lastProcessedLT = transactions[0].LT // mark last transaction as known to not trigger twice
 
@@ -271,6 +285,8 @@ func (c *APIClient) SubscribeOnTransactions(workerCtx context.Context, addr *add
 
 			wait = 0 * time.Second
 		}
+
+		timer.Reset(wait)
 	}
 }