feat: dir and file check

internal/errs/object.go

@@ -0,0 +1,16 @@
+package errs
+
+import (
+	"errors"
+	pkgerr "github.com/pkg/errors"
+)
+
+var (
+	ObjectNotFound = errors.New("object not found")
+	NotFolder      = errors.New("not a folder")
+	NotFile        = errors.New("not a file")
+)
+
+func IsObjectNotFound(err error) bool {
+	return pkgerr.Cause(err) == ObjectNotFound
+}