+static
+bool is_discarded_packet_or_event_message(const bt_message *msg)
+{
+ const enum bt_message_type msg_type = bt_message_get_type(msg);
+
+ return msg_type == BT_MESSAGE_TYPE_DISCARDED_EVENTS ||
+ msg_type == BT_MESSAGE_TYPE_DISCARDED_PACKETS;
+}
+
+static
+enum lttng_live_iterator_status adjust_discarded_packets_message(
+ bt_self_message_iterator *iter,
+ const bt_stream *stream,
+ const bt_message *msg_in, bt_message **msg_out,
+ uint64_t new_begin_ts)
+{
+ enum lttng_live_iterator_status status = LTTNG_LIVE_ITERATOR_STATUS_OK;
+ enum bt_property_availability availability;
+ const bt_clock_snapshot *clock_snapshot;
+ uint64_t end_ts;
+ uint64_t count;
+
+ clock_snapshot = bt_message_discarded_packets_borrow_end_default_clock_snapshot_const(msg_in);
+ end_ts = bt_clock_snapshot_get_value(clock_snapshot);
+
+ availability = bt_message_discarded_packets_get_count(msg_in, &count);
+ BT_ASSERT_DBG(availability == BT_PROPERTY_AVAILABILITY_AVAILABLE);
+
+ *msg_out = bt_message_discarded_packets_create_with_default_clock_snapshots(
+ iter, stream, new_begin_ts, end_ts);
+ if (!*msg_out) {
+ status = LTTNG_LIVE_ITERATOR_STATUS_NOMEM;
+ goto end;
+ }
+
+ bt_message_discarded_packets_set_count(*msg_out, count);
+end:
+ return status;
+}
+
+static
+enum lttng_live_iterator_status adjust_discarded_events_message(
+ bt_self_message_iterator *iter,
+ const bt_stream *stream,
+ const bt_message *msg_in, bt_message **msg_out,
+ uint64_t new_begin_ts)
+{
+ enum lttng_live_iterator_status status = LTTNG_LIVE_ITERATOR_STATUS_OK;
+ enum bt_property_availability availability;
+ const bt_clock_snapshot *clock_snapshot;
+ uint64_t end_ts;
+ uint64_t count;
+
+ clock_snapshot = bt_message_discarded_events_borrow_end_default_clock_snapshot_const(msg_in);
+ end_ts = bt_clock_snapshot_get_value(clock_snapshot);
+
+ availability = bt_message_discarded_events_get_count(msg_in, &count);
+ BT_ASSERT_DBG(availability == BT_PROPERTY_AVAILABILITY_AVAILABLE);
+
+ *msg_out = bt_message_discarded_events_create_with_default_clock_snapshots(
+ iter, stream, new_begin_ts, end_ts);
+ if (!*msg_out) {
+ status = LTTNG_LIVE_ITERATOR_STATUS_NOMEM;
+ goto end;
+ }
+
+ bt_message_discarded_events_set_count(*msg_out, count);
+end:
+ return status;
+}
+
+static
+enum lttng_live_iterator_status handle_late_message(
+ struct lttng_live_msg_iter *lttng_live_msg_iter,
+ struct lttng_live_stream_iterator *stream_iter,
+ int64_t late_msg_ts_ns, const bt_message *late_msg)
+{
+ bt_self_component *self_comp = lttng_live_msg_iter->self_comp;
+ bt_logging_level log_level = lttng_live_msg_iter->log_level;
+ const bt_clock_class *clock_class;
+ const bt_stream_class *stream_class;
+ enum bt_clock_class_cycles_to_ns_from_origin_status ts_ns_status;
+ int64_t last_inactivity_ts_ns;
+ enum lttng_live_iterator_status stream_iter_status = LTTNG_LIVE_ITERATOR_STATUS_OK;
+
+ stream_class = bt_stream_borrow_class_const(stream_iter->stream);
+ clock_class = bt_stream_class_borrow_default_clock_class_const(stream_class);
+
+ ts_ns_status = bt_clock_class_cycles_to_ns_from_origin(clock_class,
+ stream_iter->last_inactivity_ts.value, &last_inactivity_ts_ns);
+ if (ts_ns_status != BT_CLOCK_CLASS_CYCLES_TO_NS_FROM_ORIGIN_STATUS_OK) {
+ stream_iter_status = LTTNG_LIVE_ITERATOR_STATUS_ERROR;
+ goto end;
+ }
+
+ if (last_inactivity_ts_ns > late_msg_ts_ns &&
+ is_discarded_packet_or_event_message(late_msg)) {
+ /*
+ * The CTF message iterator emits Discarded Packets and Events
+ * with synthesized begin and end timestamps from the bounds of
+ * the last known packet and the newly decoded packet header.
+ *
+ * The CTF message iterator is not aware of stream inactivity
+ * beacons. Hence, we have to adjust the begin timestamp of
+ * those types of messages if a stream signaled its inactivity
+ * up until _after_ the last known packet's begin timestamp.
+ *
+ * Otherwise, the monotonicity guarantee would not be
+ * preserved.
+ */
+ const enum bt_message_type msg_type = bt_message_get_type(
+ late_msg);
+ enum lttng_live_iterator_status adjust_status =
+ LTTNG_LIVE_ITERATOR_STATUS_OK;
+ bt_message *adjusted_message;
+
+ switch (msg_type) {
+ case BT_MESSAGE_TYPE_DISCARDED_EVENTS:
+ adjust_status = adjust_discarded_events_message(
+ lttng_live_msg_iter->self_msg_iter,
+ stream_iter->stream,
+ late_msg, &adjusted_message,
+ stream_iter->last_inactivity_ts.value);
+ break;
+ case BT_MESSAGE_TYPE_DISCARDED_PACKETS:
+ adjust_status = adjust_discarded_packets_message(
+ lttng_live_msg_iter->self_msg_iter,
+ stream_iter->stream,
+ late_msg, &adjusted_message,
+ stream_iter->last_inactivity_ts.value);
+ break;
+ default:
+ bt_common_abort();
+ }
+
+ if (adjust_status != LTTNG_LIVE_ITERATOR_STATUS_OK) {
+ stream_iter_status = adjust_status;
+ goto end;
+ }
+
+ BT_ASSERT_DBG(adjusted_message);
+ stream_iter->current_msg = adjusted_message;
+ stream_iter->current_msg_ts_ns = last_inactivity_ts_ns;
+ } else {
+ /*
+ * We received a message in the past. To ensure
+ * monotonicity, we can't send it forward.
+ */
+ BT_COMP_LOGE_APPEND_CAUSE(self_comp,
+ "Message's timestamp is less than lttng-live's message "
+ "iterator's last returned timestamp: "
+ "lttng-live-msg-iter-addr=%p, ts=%" PRId64 ", "
+ "last-msg-ts=%" PRId64,
+ lttng_live_msg_iter, late_msg_ts_ns,
+ lttng_live_msg_iter->last_msg_ts_ns);
+ stream_iter_status = LTTNG_LIVE_ITERATOR_STATUS_ERROR;
+ goto end;
+ }
+end:
+ return stream_iter_status;
+}
+