cpp-common/bt2: add bt2::CommonEventMessage::streamClassDefaultClockClass()

This has its equivalent libbabeltrace2 function
(bt_message_event_borrow_stream_class_default_clock_class_const()), but
didn't exist.

Signed-off-by: Philippe Proulx <eeppeliteloop@gmail.com>
Change-Id: I985427cdd163341820de7dff0169b3aadcf58e0f
Reviewed-on: https://review.lttng.org/c/babeltrace/+/11416
Reviewed-by: Simon Marchi <simon.marchi@efficios.com>
Tested-by: jenkins <jenkins@lttng.org>
CI-Build: Simon Marchi <simon.marchi@efficios.com>

diff --git a/src/cpp-common/bt2/message.hpp b/src/cpp-common/bt2/message.hpp
index afc751c5df1b50275363b9c655ecbe7e92d81519..b335d8176394ab7896a7116acb1fc3b7b628e043 100644 (file)
--- a/src/cpp-common/bt2/message.hpp
+++ b/src/cpp-common/bt2/message.hpp
@@ -712,6 +712,16 @@ public:
         return _Event {internal::CommonEventMessageSpec<LibObjT>::event(this->libObjPtr())};
     }
 
+    bt2s::optional<ConstClockClass> streamClassDefaultClockClass() const noexcept
+    {
+        if (const auto libClkClsPtr =
+                bt_message_event_borrow_stream_class_default_clock_class_const(this->libObjPtr())) {
+            return ConstClockClass {libClkClsPtr};
+        }
+
+        return bt2s::nullopt;
+    }
+
     ConstClockSnapshot defaultClockSnapshot() const noexcept
     {
         const auto libObjPtr =