#1119 make sure streams are discarded when the sensor is destroyed

LibCarla/source/carla/streaming/detail/Dispatcher.cpp

@@ -32,7 +32,10 @@ namespace detail {
     // stopped.
     for (auto &pair : _stream_map) {
       try {
-        pair.second->ClearSessions();
+        auto stream_state = pair.second.lock();
+        if (stream_state != nullptr) {
+          stream_state->ClearSessions();
+        }
       } catch (const std::exception &e) {
         log_error("failed to clear sessions:", e.what());
       }
@@ -56,22 +59,27 @@ namespace detail {
     std::lock_guard<std::mutex> lock(_mutex);
     auto search = _stream_map.find(session->get_stream_id());
     if (search != _stream_map.end()) {
-      DEBUG_ASSERT(search->second != nullptr);
-      search->second->ConnectSession(std::move(session));
+      auto stream_state = search->second.lock();
+      if (stream_state != nullptr) {
+        stream_state->ConnectSession(std::move(session));
         return true;
-    } else {
+      }
+    }
     log_error("Invalid session: no stream available with id", session->get_stream_id());
     return false;
   }
-  }
 
   void Dispatcher::DeregisterSession(std::shared_ptr<Session> session) {
     DEBUG_ASSERT(session != nullptr);
     std::lock_guard<std::mutex> lock(_mutex);
     auto search = _stream_map.find(session->get_stream_id());
     if (search != _stream_map.end()) {
-      DEBUG_ASSERT(search->second != nullptr);
-      search->second->DisconnectSession(session);
+      auto stream_state = search->second.lock();
+      if (stream_state != nullptr) {
+        stream_state->DisconnectSession(session);
+      }
+    }
+  }
     }
   }
 

LibCarla/source/carla/streaming/detail/Dispatcher.h

@@ -51,7 +51,7 @@ namespace detail {
     /// them alive the whole run.
     std::unordered_map<
         stream_id_type,
-        std::shared_ptr<StreamStateBase>> _stream_map;
+        std::weak_ptr<StreamStateBase>> _stream_map;
   };
 
 } // namespace detail

Unreal/CarlaUE4/Plugins/Carla/Source/Carla/Sensor/Sensor.cpp

@@ -0,0 +1,28 @@
+// Copyright (c) 2017 Computer Vision Center (CVC) at the Universitat Autonoma
+// de Barcelona (UAB).
+//
+// This work is licensed under the terms of the MIT license.
+// For a copy, see <https://opensource.org/licenses/MIT>.
+
+#include "Carla.h"
+#include "Carla/Sensor/Sensor.h"
+
+#include "Carla/Actor/ActorDescription.h"
+#include "Carla/Actor/ActorBlueprintFunctionLibrary.h"
+
+void ASensor::Set(const FActorDescription &Description)
+{
+  // set the tick interval of the sensor
+  if (Description.Variations.Contains("sensor_tick"))
+  {
+    SetActorTickInterval(
+        UActorBlueprintFunctionLibrary::ActorAttributeToFloat(Description.Variations["sensor_tick"],
+        0.0f));
+  }
+}
+
+void ASensor::EndPlay(EEndPlayReason::Type EndPlayReason)
+{
+  Super::EndPlay(EndPlayReason);
+  Stream = FDataStream();
+}

Unreal/CarlaUE4/Plugins/Carla/Source/Carla/Sensor/Sensor.h

@@ -6,14 +6,14 @@
 
 #pragma once
 
-#include "GameFramework/Actor.h"
-
-#include "Carla/Actor/ActorDescription.h"
-#include "Carla/Actor/ActorBlueprintFunctionLibrary.h"
 #include "Carla/Sensor/DataStream.h"
 
+#include "GameFramework/Actor.h"
+
 #include "Sensor.generated.h"
 
+struct FActorDescription;
+
 /// Base class for sensors.
 UCLASS(Abstract, hidecategories = (Collision, Attachment, Actor))
 class CARLA_API ASensor : public AActor
@@ -22,16 +22,7 @@ class CARLA_API ASensor : public AActor
 
 public:
 
-  virtual void Set(const FActorDescription &Description)
-  {
-    // set the tick interval of the sensor
-    if (Description.Variations.Contains("sensor_tick"))
-    {
-      SetActorTickInterval(
-          UActorBlueprintFunctionLibrary::ActorAttributeToFloat(Description.Variations["sensor_tick"],
-          0.0f));
-    }
-  }
+  virtual void Set(const FActorDescription &Description);
 
   /// Replace the FDataStream associated with this sensor.
   ///
@@ -43,6 +34,8 @@ public:
 
 protected:
 
+  void EndPlay(EEndPlayReason::Type EndPlayReason) override;
+
   /// Return the FDataStream associated with this sensor.
   FDataStream &GetDataStream()
   {

Unreal/CarlaUE4/Plugins/Carla/Source/Carla/Server/TheNewCarlaServer.cpp

@@ -161,6 +161,10 @@ private:
     return it->second;
   }
 
+  void ClearSensorStream(FActorView ActorView) {
+    _StreamMap.erase(ActorView.GetActorId());
+  }
+
   std::unordered_map<FActorView::IdType, carla::streaming::Stream> _StreamMap;
 };
 
@@ -272,6 +276,7 @@ void FTheNewCarlaServer::FPimpl::BindActions()
       UE_LOG(LogCarlaServer, Warning, TEXT("unable to destroy actor: not found"));
       return false;
     }
+    ClearSensorStream(ActorView);
     return Episode->DestroyActor(ActorView.GetActor());
   });