Fix memory leak that string not deleted. (ros2#224)

Signed-off-by: Chen.Lihui <[email protected]>

rmw_cyclonedds_cpp/src/rmw_node.cpp

@@ -550,12 +550,21 @@ static void handle_ParticipantEntitiesInfo(dds_entity_t reader, void * arg)
 {
   static_cast<void>(reader);
   rmw_context_impl_t * impl = static_cast<rmw_context_impl_t *>(arg);
-  ParticipantEntitiesInfo msg;
   bool taken;
-  while (rmw_take(impl->common.sub, &msg, &taken, nullptr) == RMW_RET_OK && taken) {
-    // locally published data is filtered because of the subscription QoS
-    impl->common.graph_cache.update_participant_entities(msg);
-  }
+  do {
+    // TODO(iuhilnehc-ynos): Fix memory leak that string not deleted. (#224)
+    // This is a workaround to make sure calling destructor of ParticipantEntitiesInfo
+    // after calling rmw_take each time, otherwise, there will be a memory leak while
+    // deserializing a long enough buffer into a string member of NodeEntitiesInfo
+    // in ParticipantEntitiesInfo.
+    ParticipantEntitiesInfo msg;
+    if (rmw_take(impl->common.sub, &msg, &taken, nullptr) == RMW_RET_OK && taken) {
+      // locally published data is filtered because of the subscription QoS
+      impl->common.graph_cache.update_participant_entities(msg);
+    } else {
+      break;
+    }
+  } while (1);
 }
 
 static void handle_DCPSParticipant(dds_entity_t reader, void * arg)