From 2e5e0e8bac91d50212ce25ff9ffef30fc576f359 Mon Sep 17 00:00:00 2001
From: Max Schulkin <maxemijo@gmail.com>
Date: Sun, 26 Jun 2022 23:29:46 +0100
Subject: [PATCH] Add mutex on write to file function

proposed solution for https://github.com/naqvijafar91/cuteDB/issues/4
---
 blockService.go | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/blockService.go b/blockService.go
index f52f549..fcd88b0 100644
--- a/blockService.go
+++ b/blockService.go
@@ -43,6 +43,7 @@ func uint64FromBytes(b []byte) uint64 {
 
 type blockService struct {
 	file *os.File
+	mu *sync.Mutex
 }
 
 func (bs *blockService) getLatestBlockID() (int64, error) {
@@ -165,6 +166,8 @@ func (bs *blockService) newBlock() (*diskBlock, error) {
 }
 
 func (bs *blockService) writeBlockToDisk(block *diskBlock) error {
+	bs.mu.Lock()
+	defer bs.mu.Unlock()
 	seekOffset := blockSize * block.id
 	blockBuffer := bs.getBufferFromBlock(block)
 	_, err := bs.file.Seek(int64(seekOffset), 0)
@@ -240,7 +243,7 @@ func (bs *blockService) updateRootNode(n *DiskNode) error {
 }
 
 func newBlockService(file *os.File) *blockService {
-	return &blockService{file}
+	return &blockService{file: file, mu: &sync.Mutex{}}
 }
 
 func (bs *blockService) rootBlockExists() bool {