added directory listing cache

pkg/fs/fs.go

@@ -28,6 +28,7 @@ type FS struct {
 	dst     string
 	mdf     *os.File
 	jenc    *json.Encoder
+	dc      *DirCache
 	mm      map[string]*Metadata
 	prem    map[string]func()
 	cancel  func()
@@ -56,6 +57,7 @@ func NewFS(src, dst, metadata string, log logr.Logger) (fs *FS, err error) {
 		src:     src,
 		dst:     dst,
 		mdf:     mdf,
+		dc:      NewDirCache(),
 		mm:      make(map[string]*Metadata),
 		prem:    make(map[string]func()),
 		jenc:    json.NewEncoder(mdf),
@@ -197,7 +199,7 @@ func (fs *FS) Open(name string) (f http.File, err error) {
 			offline = true
 			log.V(2).Info("dir offline mode", "path", dp)
 		}
-		return &Dir{f: sf}, err
+		return &Dir{f: sf, dc: fs.dc}, err
 	}
 	md := fs.metadata(name, sfi.Size())
 	return &File{