fix possible race in line cache

Author: andreykuchin

pkg/fsutils/linecache.go

@@ -3,20 +3,20 @@ package fsutils
 import (
 	"bytes"
 	"fmt"
+	"sync"
 
 	"github.com/pkg/errors"
 )
 
 type fileLinesCache [][]byte
 
 type LineCache struct {
-	files     map[string]fileLinesCache
+	files     sync.Map
 	fileCache *FileCache
 }
 
 func NewLineCache(fc *FileCache) *LineCache {
 	return &LineCache{
-		files:     map[string]fileLinesCache{},
 		fileCache: fc,
 	}
 }
@@ -53,17 +53,17 @@ func (lc *LineCache) getRawLine(filePath string, index0 int) ([]byte, error) {
 }
 
 func (lc *LineCache) getFileCache(filePath string) (fileLinesCache, error) {
-	fc := lc.files[filePath]
-	if fc != nil {
-		return fc, nil
+	loadedFc, ok := lc.files.Load(filePath)
+	if ok {
+		return loadedFc.(fileLinesCache), nil
 	}
 
 	fileBytes, err := lc.fileCache.GetFileBytes(filePath)
 	if err != nil {
 		return nil, errors.Wrapf(err, "can't get file %s bytes from cache", filePath)
 	}
 
-	fc = bytes.Split(fileBytes, []byte("\n"))
-	lc.files[filePath] = fc
+	fc := bytes.Split(fileBytes, []byte("\n"))
+	lc.files.Store(filePath, fileLinesCache(fc))
 	return fc, nil
 }