Implement get_actual_qos() for subscriptions

[mm318]

Currently, publishers have the get_actual_qos() feature/function. It would make sense for subscriptions to have them, too.

[ivanpauno]

In general, LGTM.

Is it possible to implement a function to avoid having duplicated code with rmw_publisher.cpp?

rmw_fastrtps/rmw_fastrtps_shared_cpp/src/rmw_publisher.cpp

Lines 149 to 207 in 015f1ee

	switch (attributes.topic.historyQos.kind) {
	case eprosima::fastrtps::KEEP_LAST_HISTORY_QOS:
	qos->history = RMW_QOS_POLICY_HISTORY_KEEP_LAST;
	break;
	case eprosima::fastrtps::KEEP_ALL_HISTORY_QOS:
	qos->history = RMW_QOS_POLICY_HISTORY_KEEP_ALL;
	break;
	default:
	qos->history = RMW_QOS_POLICY_HISTORY_UNKNOWN;
	break;
	}
	qos->depth = static_cast<size_t>(attributes.topic.historyQos.depth);
	switch (attributes.qos.m_reliability.kind) {
	case eprosima::fastrtps::BEST_EFFORT_RELIABILITY_QOS:
	qos->reliability = RMW_QOS_POLICY_RELIABILITY_BEST_EFFORT;
	break;
	case eprosima::fastrtps::RELIABLE_RELIABILITY_QOS:
	qos->reliability = RMW_QOS_POLICY_RELIABILITY_RELIABLE;
	break;
	default:
	qos->reliability = RMW_QOS_POLICY_RELIABILITY_UNKNOWN;
	break;
	}
	switch (attributes.qos.m_durability.kind) {
	case eprosima::fastrtps::TRANSIENT_LOCAL_DURABILITY_QOS:
	qos->durability = RMW_QOS_POLICY_DURABILITY_TRANSIENT_LOCAL;
	break;
	case eprosima::fastrtps::VOLATILE_DURABILITY_QOS:
	qos->durability = RMW_QOS_POLICY_DURABILITY_VOLATILE;
	break;
	default:
	qos->durability = RMW_QOS_POLICY_DURABILITY_UNKNOWN;
	break;
	}
	qos->deadline.sec = attributes.qos.m_deadline.period.seconds;
	qos->deadline.nsec = attributes.qos.m_deadline.period.nanosec;
	qos->lifespan.sec = attributes.qos.m_lifespan.duration.seconds;
	qos->lifespan.nsec = attributes.qos.m_lifespan.duration.nanosec;
	switch (attributes.qos.m_liveliness.kind) {
	case eprosima::fastrtps::AUTOMATIC_LIVELINESS_QOS:
	qos->liveliness = RMW_QOS_POLICY_LIVELINESS_AUTOMATIC;
	break;
	case eprosima::fastrtps::MANUAL_BY_PARTICIPANT_LIVELINESS_QOS:
	qos->liveliness = RMW_QOS_POLICY_LIVELINESS_MANUAL_BY_NODE;
	break;
	case eprosima::fastrtps::MANUAL_BY_TOPIC_LIVELINESS_QOS:
	qos->liveliness = RMW_QOS_POLICY_LIVELINESS_MANUAL_BY_TOPIC;
	break;
	default:
	qos->liveliness = RMW_QOS_POLICY_LIVELINESS_UNKNOWN;
	break;
	}
	qos->liveliness_lease_duration.sec = attributes.qos.m_liveliness.lease_duration.seconds;
	qos->liveliness_lease_duration.nsec = attributes.qos.m_liveliness.lease_duration.nanosec;

Maybe, something like:

template<typename AttributeT>
void
from_attributes_to_rmw_qos(
  const AttributeT * attr,
  rmw_qos_profile_t * qos);

Edit: https://github.com/ros2/rmw_fastrtps/blob/master/rmw_fastrtps_shared_cpp/src/qos.cpp is a good place for that function.

[mm318]

Refactored to avoid duplicate code. Thanks!

[ivanpauno]

I left a minimal comment. LGTM!

[ivanpauno]

any reason for moving this declaration?

[mm318]

I felt it would be more consistent with the rest of the rmw implementations that the dds_qos_to_rmw_qos() follows get_datareader_qos(). is_valid_qos() is also the first function among the ones declared here to be called in a normal program flow.

[ivanpauno]

Sounds good

[ivanpauno]

CI: ros2/rmw#177 (comment)