From f2e32d8b4f15dcd1afed58e1569b2270bab7ca12 Mon Sep 17 00:00:00 2001
From: Kelvin Clement Mwinuka <kelvinmwinuka@hotmail.co.uk>
Date: Sun, 25 Feb 2024 12:07:41 +0800
Subject: [PATCH] Implemented truncate of preamble and aof files

---
 src/server/aof/aof_engine.go     | 19 +++++++++----------
 src/server/aof/aof_store.go      | 10 ++++++++++
 src/server/aof/preamble_store.go | 13 +++++++++++++
 3 files changed, 32 insertions(+), 10 deletions(-)

diff --git a/src/server/aof/aof_engine.go b/src/server/aof/aof_engine.go
index 4b5b2e5b..ae8035f3 100644
--- a/src/server/aof/aof_engine.go
+++ b/src/server/aof/aof_engine.go
@@ -47,7 +47,7 @@ func NewAOFEngine(opts Opts, appendRW io.ReadWriter, preambleRW io.ReadWriter) (
 	// Obtain preamble file handler
 	if preambleRW == nil {
 		f, err := os.OpenFile(
-			path.Join(engine.options.Config.DataDir, "aof", "peamble.bin"),
+			path.Join(engine.options.Config.DataDir, "aof", "preamble.bin"),
 			os.O_WRONLY|os.O_CREATE|os.O_APPEND,
 			os.ModePerm)
 		if err != nil {
@@ -135,16 +135,15 @@ func (engine *Engine) RewriteLog() error {
 	engine.options.StartRewriteAOF()
 	defer engine.options.FinishRewriteAOF()
 
-	// Replace aof file with empty file.
-	aof, err := os.Create(path.Join(engine.options.Config.DataDir, "aof", "log.aof"))
-	if err != nil {
-		return err
+	// Create AOF preamble
+	if err := engine.preambleStore.CreatePreamble(); err != nil {
+		log.Println(err)
+	}
+
+	// Truncate the AOF file.
+	if err := engine.appendStore.Truncate(); err != nil {
+		log.Println(err)
 	}
-	defer func() {
-		if err = aof.Close(); err != nil {
-			log.Println(err)
-		}
-	}()
 
 	return nil
 }
diff --git a/src/server/aof/aof_store.go b/src/server/aof/aof_store.go
index aaf3c290..45bbb4e8 100644
--- a/src/server/aof/aof_store.go
+++ b/src/server/aof/aof_store.go
@@ -5,6 +5,7 @@ import (
 	"bytes"
 	"context"
 	"errors"
+	"fmt"
 	"io"
 	"net"
 	"os"
@@ -77,6 +78,15 @@ func (store *AppendStore) Restore(ctx context.Context) error {
 }
 
 func (store *AppendStore) Truncate() error {
+	rw, ok := store.rw.(interface {
+		Truncate(size int64) error
+	})
+	if !ok {
+		fmt.Println("could not truncate AOF file")
+	}
+	if err := rw.Truncate(0); err != nil {
+		return err
+	}
 	return nil
 }
 
diff --git a/src/server/aof/preamble_store.go b/src/server/aof/preamble_store.go
index e3901abc..c1a352e7 100644
--- a/src/server/aof/preamble_store.go
+++ b/src/server/aof/preamble_store.go
@@ -3,6 +3,7 @@ package aof
 import (
 	"context"
 	"encoding/json"
+	"errors"
 	"io"
 	"log"
 	"os"
@@ -65,6 +66,18 @@ func (store *PreambleStore) CreatePreamble() error {
 		return err
 	}
 
+	// Truncate the preamble first
+	rw, ok := store.rw.(interface {
+		Truncate(size int64) error
+	})
+	if !ok {
+		return errors.New("could not truncate preamble file")
+	}
+
+	if err = rw.Truncate(0); err != nil {
+		return err
+	}
+
 	if _, err = store.rw.Write(o); err != nil {
 		return err
 	}