librbd: introduce TypeTraits in librbd/image

Signed-off-by: Dongsheng Yang <dongsheng.yang@easystack.cn>

diff --git a/src/librbd/image/TypeTraits.h b/src/librbd/image/TypeTraits.h
new file mode 100644 (file)
index 0000000..17d84fc
--- /dev/null
+++ b/src/librbd/image/TypeTraits.h
@@ -0,0 +1,20 @@
+// -*- mode:C++; tab-width:8; c-basic-offset:2; indent-tabs-mode:t -*-
+// vim: ts=8 sw=2 smarttab
+
+#ifndef CEPH_LIBRBD_IMAGE_TYPE_TRAITS_H
+#define CEPH_LIBRBD_IMAGE_TYPE_TRAITS_H
+
+class ContextWQ;
+
+namespace librbd {
+namespace image {
+
+template <typename ImageCtxT>
+struct TypeTraits {
+  typedef ::ContextWQ ContextWQ;
+};
+
+} // namespace image
+} // namespace librbd
+
+#endif // CEPH_LIBRBD_IMAGE_TYPE_TRAITS_H