Add message lost subscription event

Signed-off-by: Ivan Santiago Paunovic <[email protected]>

rmw/include/rmw/event.h

@@ -29,7 +29,7 @@ extern "C"
 #include "rmw/ret_types.h"
 #include "rmw/visibility_control.h"
 
-/// Define QoS policy events
+/// Define publisher/subscription events
 typedef enum rmw_event_type_t
 {
   // subscription events
@@ -41,6 +41,7 @@ typedef enum rmw_event_type_t
   RMW_EVENT_LIVELINESS_LOST,
   RMW_EVENT_OFFERED_DEADLINE_MISSED,
   RMW_EVENT_OFFERED_QOS_INCOMPATIBLE,
+  RMW_EVENT_MESSAGE_LOST,
 
   // sentinel value
   RMW_EVENT_INVALID

rmw/include/rmw/events_statuses/events_statuses.h

@@ -18,6 +18,7 @@
 #include "rmw/events_statuses/incompatible_qos.h"
 #include "rmw/events_statuses/liveliness_changed.h"
 #include "rmw/events_statuses/liveliness_lost.h"
+#include "rmw/events_statuses/message_lost.h"
 #include "rmw/events_statuses/offered_deadline_missed.h"
 #include "rmw/events_statuses/requested_deadline_missed.h"
 

rmw/include/rmw/events_statuses/message_lost.h

@@ -0,0 +1,39 @@
+// Copyright 2020 Open Source Robotics Foundation, Inc.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#ifndef RMW__EVENTS_STATUSES__MESSAGE_LOST_H_
+#define RMW__EVENTS_STATUSES__MESSAGE_LOST_H_
+
+#include <stddef.h>
+
+#include "rmw/visibility_control.h"
+
+#ifdef __cplusplus
+extern "C"
+{
+#endif
+
+typedef struct RMW_PUBLIC_TYPE rmw_message_lost_status_t
+{
+  /// Total number of messages lost.
+  size_t total_count;
+  /// Number of messages lost since last callback.
+  size_t total_count_change;
+} rmw_message_lost_status_t;
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif  // RMW__EVENTS_STATUSES__MESSAGE_LOST_H_