From 91f1edfc811fdebd4d1af9507a1bce84ea334f08 Mon Sep 17 00:00:00 2001
From: Leon Friedrich <60421075+ElectroJr@users.noreply.github.com>
Date: Sat, 14 Jan 2023 13:50:32 +1300
Subject: [PATCH] Cache MapUid (#3687)

---
 .../Transform/TransformComponent.cs           | 18 +++++++-------
 .../SharedTransformSystem.Component.cs        | 24 ++++---------------
 2 files changed, 12 insertions(+), 30 deletions(-)

diff --git a/Robust.Shared/GameObjects/Components/Transform/TransformComponent.cs b/Robust.Shared/GameObjects/Components/Transform/TransformComponent.cs
index d2c6cd026d..293064212f 100644
--- a/Robust.Shared/GameObjects/Components/Transform/TransformComponent.cs
+++ b/Robust.Shared/GameObjects/Components/Transform/TransformComponent.cs
@@ -99,14 +99,7 @@ namespace Robust.Shared.GameObjects
         /// <summary>
         ///     The EntityUid of the map which this object is on, if any.
         /// </summary>
-        public EntityUid? MapUid
-        {
-            get
-            {
-                var id = _mapManager.GetMapEntityId(MapID);
-                return id.IsValid() ? id : null;
-            }
-        }
+        public EntityUid? MapUid { get; internal set; }
 
         /// <summary>
         ///     The EntityUid of the grid which this object is on, if any.
@@ -485,6 +478,8 @@ namespace Robust.Shared.GameObjects
             if (newMapId == MapID)
                 return;
 
+            EntityUid? newUid = newMapId == MapId.Nullspace ? null : _mapManager.GetMapEntityId(newMapId);
+
             //Set Paused state
             var mapPaused = _mapManager.IsMapPaused(newMapId);
             var metaEnts = _entMan.GetEntityQuery<MetaDataComponent>();
@@ -492,12 +487,14 @@ namespace Robust.Shared.GameObjects
             var metaSystem = _entMan.EntitySysManager.GetEntitySystem<MetaDataSystem>();
             metaSystem.SetEntityPaused(Owner, mapPaused, metaData);
 
+            MapUid = newUid;
             MapID = newMapId;
-            UpdateChildMapIdsRecursive(MapID, mapPaused, xformQuery, metaEnts, metaSystem);
+            UpdateChildMapIdsRecursive(MapID, newUid, mapPaused, xformQuery, metaEnts, metaSystem);
         }
 
         internal void UpdateChildMapIdsRecursive(
             MapId newMapId,
+            EntityUid? newUid,
             bool mapPaused,
             EntityQuery<TransformComponent> xformQuery,
             EntityQuery<MetaDataComponent> metaQuery,
@@ -513,11 +510,12 @@ namespace Robust.Shared.GameObjects
 
                 var concrete = xformQuery.GetComponent(child.Value);
 
+                concrete.MapUid = newUid;
                 concrete.MapID = newMapId;
 
                 if (concrete.ChildCount != 0)
                 {
-                    concrete.UpdateChildMapIdsRecursive(newMapId, mapPaused, xformQuery, metaQuery, system);
+                    concrete.UpdateChildMapIdsRecursive(newMapId, newUid, mapPaused, xformQuery, metaQuery, system);
                 }
             }
         }
diff --git a/Robust.Shared/GameObjects/Systems/SharedTransformSystem.Component.cs b/Robust.Shared/GameObjects/Systems/SharedTransformSystem.Component.cs
index e786362f0b..a687393a75 100644
--- a/Robust.Shared/GameObjects/Systems/SharedTransformSystem.Component.cs
+++ b/Robust.Shared/GameObjects/Systems/SharedTransformSystem.Component.cs
@@ -182,7 +182,7 @@ public abstract partial class SharedTransformSystem
         // Children MAY be initialized here before their parents are.
         // We do this whole dance to handle this recursively,
         // setting _mapIdInitialized along the way to avoid going to the MapComponent every iteration.
-        static MapId FindMapIdAndSet(TransformComponent xform, IEntityManager entMan, EntityQuery<TransformComponent> xformQuery)
+        static MapId FindMapIdAndSet(TransformComponent xform, IEntityManager entMan, EntityQuery<TransformComponent> xformQuery, IMapManager mapManager)
         {
             if (xform._mapIdInitialized)
                 return xform.MapID;
@@ -191,7 +191,7 @@ public abstract partial class SharedTransformSystem
 
             if (xform.ParentUid.IsValid())
             {
-                value = FindMapIdAndSet(xformQuery.GetComponent(xform.ParentUid), entMan, xformQuery);
+                value = FindMapIdAndSet(xformQuery.GetComponent(xform.ParentUid), entMan, xformQuery, mapManager);
             }
             else
             {
@@ -207,6 +207,7 @@ public abstract partial class SharedTransformSystem
                 }
             }
 
+            xform.MapUid = value == MapId.Nullspace ? null : mapManager.GetMapEntityId(value);
             xform.MapID = value;
             xform._mapIdInitialized = true;
             return value;
@@ -216,7 +217,7 @@ public abstract partial class SharedTransformSystem
 
         if (!component._mapIdInitialized)
         {
-            FindMapIdAndSet(component, EntityManager, xformQuery);
+            FindMapIdAndSet(component, EntityManager, xformQuery, _mapManager);
             component._mapIdInitialized = true;
         }
 
@@ -1124,23 +1125,6 @@ public abstract partial class SharedTransformSystem
     #endregion
 
     #region State Handling
-    private void ChangeMapId(TransformComponent xform, MapId newMapId, EntityQuery<TransformComponent> xformQuery, EntityQuery<MetaDataComponent> metaQuery)
-    {
-        if (newMapId == xform.MapID)
-            return;
-
-        //Set Paused state
-        var mapPaused = _mapManager.IsMapPaused(newMapId);
-        var meta = metaQuery.GetComponent(xform.Owner);
-        _metaSys.SetEntityPaused(xform.Owner, mapPaused, meta);
-
-        // Map entities retain their map Uids
-        if (xform.Owner != xform.MapUid)
-            xform.MapID = newMapId;
-
-        xform.UpdateChildMapIdsRecursive(newMapId, mapPaused, xformQuery, metaQuery, _metaSys);
-    }
-
     public void DetachParentToNull(TransformComponent xform)
     {
         if (xform._parent.IsValid())