ObjectMap.cc

template <typename I>
void ObjectMap<I>::rollback(uint64_t snap_id, Context *on_finish) {
  ceph_assert(m_image_ctx.snap_lock.is_locked());
  ceph_assert(m_image_ctx.object_map_lock.is_wlocked());

  using klass = ObjectMap<I>;
  Context *ctx = create_context_callback<klass>(this, on_finish);

  object_map::SnapshotRollbackRequest *req =
    new object_map::SnapshotRollbackRequest(m_image_ctx, snap_id, ctx);
  req->send();
}

Utils.h

template <typename T>
class C_ContextCallbackAdapter : public Context {
  T *obj;
  Context *on_finish;

public:
  C_ContextCallbackAdapter(T *obj, Context *on_finish)
    : obj(obj), on_finish(on_finish) {
    obj->get();
  }

  ~C_ContextCallbackAdapter() {
    obj->put();
  }

protected:
  void finish(int r) override {
    on_finish->complete(r);
  }

};

template <typename T>
Context *create_context_callback(T *obj, Context *on_finish) {
  return new detail::C_ContextCallbackAdapter<T>(obj, on_finish);
}