UTY-2504: Nullable command response

CHANGELOG.md

@@ -17,6 +17,7 @@
     - See the [upgrade guide](UPGRADE_GUIDE.md) for detailed upgrade instructions for this breaking change.
     - `IEntityGameObjectCreator.PopulateEntityTypeExpectations` now only needs to specify what SpatialOS components it needs for spawning an entity, such as `Position`.
     - `GameObjectCreationHelper.EnableStandardGameObjectCreation` now requires a non-null `EntityRepresentationMapping` to be passed in.
+- The `GetResponse<T>(CommandRequestId)` method in the `IDiffCommandResponseStorage` and `CommandSystem` now returns a `T?` instead of `MessageSpan<T>` [#1428](https://github.com/spatialos/gdk-for-unity/pull/1428)
 
 ### Added
 

workers/unity/Assets/Playground/Scripts/Player/PlayerCommandsSystem.cs

@@ -1,6 +1,7 @@
 using System;
 using Improbable;
 using Improbable.Gdk.Core;
+using Improbable.Gdk.Core.Commands;
 using Playground.Scripts.UI;
 using Unity.Collections;
 using Unity.Entities;
@@ -26,6 +27,9 @@ private enum PlayerCommand
         private CommandSystem commandSystem;
         private EntityQuery launchGroup;
 
+#if UNITY_EDITOR
+        private CommandRequestId? lastId;
+#endif
         protected override void OnCreate()
         {
             base.OnCreate();
@@ -39,6 +43,22 @@ protected override void OnCreate()
 
         protected override void OnUpdate()
         {
+#if UNITY_EDITOR
+            if (lastId.HasValue)
+            {
+                var response = commandSystem.GetResponse<Launcher.LaunchEntity.ReceivedResponse>(lastId.Value);
+                if (response.HasValue)
+                {
+                    Debug.Log($"Launch {response.Value.RequestId.Raw} successful, with response {response.Value}");
+                    lastId = null;
+                }
+                else
+                {
+                    Debug.Log($"Could not find response for Launch {lastId.Value.Raw}");
+                }
+            }
+#endif
+
             using (var entities = launchGroup.ToEntityArray(Allocator.TempJob))
             using (var spatialIdData = launchGroup.ToComponentDataArray<SpatialEntityId>(Allocator.TempJob))
             {
@@ -86,8 +106,12 @@ protected override void OnUpdate()
                         command == PlayerCommand.LaunchLarge ? LargeEnergy : SmallEnergy,
                         playerId
                     ));
-
+#if UNITY_EDITOR
+                lastId = commandSystem.SendCommand(request, entities[0]);
+                Debug.Log($"Launching {lastId.Value.Raw}");
+#else
                 commandSystem.SendCommand(request, entities[0]);
+#endif
             }
         }
     }

workers/unity/Packages/io.improbable.gdk.core/Commands/CommandDiffStorageBase.cs

@@ -69,7 +69,7 @@ public MessagesSpan<TResponse> GetResponses()
             return responseStorage.Slice();
         }
 
-        public MessagesSpan<TResponse> GetResponse(CommandRequestId requestId)
+        public TResponse? GetResponse(CommandRequestId requestId)
         {
             if (!responsesSorted)
             {
@@ -78,9 +78,7 @@ public MessagesSpan<TResponse> GetResponse(CommandRequestId requestId)
             }
 
             var responseIndex = responseStorage.GetResponseIndex(requestId);
-            return responseIndex.HasValue
-                ? responseStorage.Slice(responseIndex.Value, 1)
-                : MessagesSpan<TResponse>.Empty();
+            return responseIndex.HasValue ? responseStorage[responseIndex.Value] : (TResponse?) null;
         }
 
         private sealed class RequestComparer<T> : IComparer<T> where T : struct, IReceivedCommandRequest

workers/unity/Packages/io.improbable.gdk.core/Systems/CommandSystem.cs

@@ -40,7 +40,7 @@ public MessagesSpan<T> GetResponses<T>() where T : struct, IReceivedCommandRespo
             return manager.GetResponses();
         }
 
-        public MessagesSpan<T> GetResponse<T>(CommandRequestId requestId) where T : struct, IReceivedCommandResponse
+        public T? GetResponse<T>(CommandRequestId requestId) where T : struct, IReceivedCommandResponse
         {
             var manager = (IDiffCommandResponseStorage<T>) worker.Diff.GetCommandDiffStorage(typeof(T));
             return manager.GetResponse(requestId);

workers/unity/Packages/io.improbable.gdk.core/Worker/DiffStorage.cs

@@ -73,6 +73,6 @@ public interface IDiffCommandResponseStorage<T> : ICommandDiffStorage
     {
         void AddResponse(T response);
         MessagesSpan<T> GetResponses();
-        MessagesSpan<T> GetResponse(CommandRequestId requestId);
+        T? GetResponse(CommandRequestId requestId);
     }
 }

workers/unity/Packages/io.improbable.gdk.core/Worker/WorldCommandsReceivedStorage.cs

@@ -84,8 +84,7 @@ public void AddResponse(WorldCommands.EntityQuery.ReceivedResponse response)
             return entityQueryResponses.Slice();
         }
 
-        MessagesSpan<WorldCommands.CreateEntity.ReceivedResponse>
-            IDiffCommandResponseStorage<WorldCommands.CreateEntity.ReceivedResponse>.GetResponse(CommandRequestId requestId)
+        WorldCommands.CreateEntity.ReceivedResponse? IDiffCommandResponseStorage<WorldCommands.CreateEntity.ReceivedResponse>.GetResponse(CommandRequestId requestId)
         {
             if (!createEntitySorted)
             {
@@ -95,11 +94,11 @@ public void AddResponse(WorldCommands.EntityQuery.ReceivedResponse response)
 
             var responseIndex = createEntityResponses.GetResponseIndex(requestId);
             return responseIndex.HasValue
-                ? createEntityResponses.Slice(responseIndex.Value, 1)
-                : MessagesSpan<WorldCommands.CreateEntity.ReceivedResponse>.Empty();
+                ? createEntityResponses[responseIndex.Value]
+                : (WorldCommands.CreateEntity.ReceivedResponse?) null;
         }
 
-        MessagesSpan<WorldCommands.DeleteEntity.ReceivedResponse>
+        WorldCommands.DeleteEntity.ReceivedResponse?
             IDiffCommandResponseStorage<WorldCommands.DeleteEntity.ReceivedResponse>.GetResponse(CommandRequestId requestId)
         {
             if (!deleteEntitySorted)
@@ -110,11 +109,11 @@ public void AddResponse(WorldCommands.EntityQuery.ReceivedResponse response)
 
             var responseIndex = deleteEntityResponses.GetResponseIndex(requestId);
             return responseIndex.HasValue
-                ? deleteEntityResponses.Slice(responseIndex.Value, 1)
-                : MessagesSpan<WorldCommands.DeleteEntity.ReceivedResponse>.Empty();
+                ? deleteEntityResponses[responseIndex.Value]
+                : (WorldCommands.DeleteEntity.ReceivedResponse?) null;
         }
 
-        MessagesSpan<WorldCommands.ReserveEntityIds.ReceivedResponse>
+        WorldCommands.ReserveEntityIds.ReceivedResponse?
             IDiffCommandResponseStorage<WorldCommands.ReserveEntityIds.ReceivedResponse>.GetResponse(CommandRequestId requestId)
         {
             if (!reserveEntityIdsSorted)
@@ -125,11 +124,11 @@ public void AddResponse(WorldCommands.EntityQuery.ReceivedResponse response)
 
             var responseIndex = reserveEntityIdsResponses.GetResponseIndex(requestId);
             return responseIndex.HasValue
-                ? reserveEntityIdsResponses.Slice(responseIndex.Value, 1)
-                : MessagesSpan<WorldCommands.ReserveEntityIds.ReceivedResponse>.Empty();
+                ? reserveEntityIdsResponses[responseIndex.Value]
+                : (WorldCommands.ReserveEntityIds.ReceivedResponse?) null;
         }
 
-        MessagesSpan<WorldCommands.EntityQuery.ReceivedResponse>
+        WorldCommands.EntityQuery.ReceivedResponse?
             IDiffCommandResponseStorage<WorldCommands.EntityQuery.ReceivedResponse>.GetResponse(CommandRequestId requestId)
         {
             if (!entityQueriesSorted)
@@ -140,8 +139,8 @@ public void AddResponse(WorldCommands.EntityQuery.ReceivedResponse response)
 
             var responseIndex = entityQueryResponses.GetResponseIndex(requestId);
             return responseIndex.HasValue
-                ? entityQueryResponses.Slice(responseIndex.Value, 1)
-                : MessagesSpan<WorldCommands.EntityQuery.ReceivedResponse>.Empty();
+                ? entityQueryResponses[responseIndex.Value]
+                : (WorldCommands.EntityQuery.ReceivedResponse?) null;
         }
 
         private class Comparer : IComparer<WorldCommands.CreateEntity.ReceivedResponse>,