Dreamview: fix a relative_map race

modules/dreamview/backend/simulation_world/simulation_world_service.cc

@@ -963,6 +963,13 @@ template <>
 void SimulationWorldService::UpdateSimulationWorld(const MapMsg &map_msg) {
   if (map_msg.has_hdmap()) {
     relative_map_.CopyFrom(map_msg.hdmap());
+    for (int i = 0; i < relative_map_.lane_size(); ++i) {
+      auto *lane = relative_map_.mutable_lane(i);
+      lane->clear_left_sample();
+      lane->clear_right_sample();
+      lane->clear_left_road_sample();
+      lane->clear_right_road_sample();
+    }
   }
 }
 

modules/dreamview/backend/simulation_world/simulation_world_updater.cc

@@ -81,10 +81,12 @@ void SimulationWorldUpdater::RegisterMessageHandlers() {
   map_ws_->RegisterMessageHandler(
       "RetrieveRelativeMapData",
       [this](const Json &json, WebSocketHandler::Connection *conn) {
-        std::string retrieved_map_string;
-        sim_world_service_.GetRelativeMap().SerializeToString(
-            &retrieved_map_string);
-        map_ws_->SendBinaryData(conn, retrieved_map_string, true);
+        std::string to_send;
+        {
+          boost::shared_lock<boost::shared_mutex> reader_lock(mutex_);
+          to_send = relative_map_string_;
+        }
+        map_ws_->SendBinaryData(conn, to_send, true);
       });
 
   websocket_->RegisterMessageHandler(
@@ -348,6 +350,8 @@ void SimulationWorldUpdater::OnTimer(const ros::TimerEvent &event) {
     sim_world_service_.GetWireFormatString(
         FLAGS_sim_map_radius, &simulation_world_,
         &simulation_world_with_planning_data_);
+    sim_world_service_.GetRelativeMap().SerializeToString(
+        &relative_map_string_);
   }
 }
 

modules/dreamview/backend/simulation_world/simulation_world_updater.h

@@ -136,6 +136,9 @@ class SimulationWorldUpdater {
   std::string simulation_world_;
   std::string simulation_world_with_planning_data_;
 
+  // Received relative map data in wire format.
+  std::string relative_map_string_;
+
   // Mutex to protect concurrent access to simulation_world_json_.
   // NOTE: Use boost until we have std version of rwlock support.
   boost::shared_mutex mutex_;