From b9a805b352722b18d075147da1aa61916cb8b594 Mon Sep 17 00:00:00 2001
From: metalgearsloth <31366439+metalgearsloth@users.noreply.github.com>
Date: Wed, 1 Mar 2023 03:05:29 +1100
Subject: [PATCH] Reduce some state handling allocs (#14301)

---
 Content.Shared/Doors/Systems/SharedDoorSystem.cs   |  5 +++--
 Content.Shared/Mobs/Systems/MobStateSystem.cs      |  7 ++++++-
 Content.Shared/Mobs/Systems/MobThresholdSystem.cs  | 12 +++++++++++-
 .../StepTrigger/Systems/StepTriggerSystem.cs       | 14 ++++++++++----
 4 files changed, 30 insertions(+), 8 deletions(-)

diff --git a/Content.Shared/Doors/Systems/SharedDoorSystem.cs b/Content.Shared/Doors/Systems/SharedDoorSystem.cs
index c8db06b792..bb590a32d9 100644
--- a/Content.Shared/Doors/Systems/SharedDoorSystem.cs
+++ b/Content.Shared/Doors/Systems/SharedDoorSystem.cs
@@ -108,9 +108,10 @@ public abstract class SharedDoorSystem : EntitySystem
         if (args.Current is not DoorComponentState state)
             return;
 
-        if (!door.CurrentlyCrushing.Equals(state.CurrentlyCrushing))
+        if (!door.CurrentlyCrushing.SetEquals(state.CurrentlyCrushing))
         {
-            door.CurrentlyCrushing = new(state.CurrentlyCrushing);
+            door.CurrentlyCrushing.Clear();
+            door.CurrentlyCrushing.UnionWith(state.CurrentlyCrushing);
         }
 
         door.State = state.DoorState;
diff --git a/Content.Shared/Mobs/Systems/MobStateSystem.cs b/Content.Shared/Mobs/Systems/MobStateSystem.cs
index 4be7715a98..ad2de1c801 100644
--- a/Content.Shared/Mobs/Systems/MobStateSystem.cs
+++ b/Content.Shared/Mobs/Systems/MobStateSystem.cs
@@ -104,7 +104,12 @@ public partial class MobStateSystem : EntitySystem
             return;
 
         component.CurrentState = state.CurrentState;
-        component.AllowedStates = new HashSet<MobState>(state.AllowedStates);
+
+        if (!component.AllowedStates.SetEquals(state.AllowedStates))
+        {
+            component.AllowedStates.Clear();
+            component.AllowedStates.UnionWith(state.AllowedStates);
+        }
     }
 
     private void OnGetComponentState(EntityUid uid, MobStateComponent component, ref ComponentGetState args)
diff --git a/Content.Shared/Mobs/Systems/MobThresholdSystem.cs b/Content.Shared/Mobs/Systems/MobThresholdSystem.cs
index c84fd097d9..dabd998ebc 100644
--- a/Content.Shared/Mobs/Systems/MobThresholdSystem.cs
+++ b/Content.Shared/Mobs/Systems/MobThresholdSystem.cs
@@ -340,7 +340,17 @@ public sealed class MobThresholdSystem : EntitySystem
         if (args.Current is not MobThresholdComponentState state)
             return;
 
-        component.Thresholds = new SortedDictionary<FixedPoint2, MobState>(state.Thresholds);
+        if (component.Thresholds.Count != state.Thresholds.Count ||
+            !component.Thresholds.SequenceEqual(state.Thresholds))
+        {
+            component.Thresholds.Clear();
+
+            foreach (var threshold in state.Thresholds)
+            {
+                component.Thresholds.Add(threshold.Key, threshold.Value);
+            }
+        }
+
         component.CurrentThresholdState = state.CurrentThresholdState;
     }
 
diff --git a/Content.Shared/StepTrigger/Systems/StepTriggerSystem.cs b/Content.Shared/StepTrigger/Systems/StepTriggerSystem.cs
index 72415ed839..b6398ca21d 100644
--- a/Content.Shared/StepTrigger/Systems/StepTriggerSystem.cs
+++ b/Content.Shared/StepTrigger/Systems/StepTriggerSystem.cs
@@ -150,11 +150,17 @@ public sealed class StepTriggerSystem : EntitySystem
         component.IntersectRatio = state.IntersectRatio;
         component.Active = state.Active;
 
-        component.CurrentlySteppedOn.Clear();
-        component.Colliding.Clear();
+        if (!component.CurrentlySteppedOn.SetEquals(state.CurrentlySteppedOn))
+        {
+            component.CurrentlySteppedOn.Clear();
+            component.CurrentlySteppedOn.UnionWith(state.CurrentlySteppedOn);
+        }
 
-        component.CurrentlySteppedOn.UnionWith(state.CurrentlySteppedOn);
-        component.Colliding.UnionWith(state.Colliding);
+        if (!component.Colliding.SetEquals(state.Colliding))
+        {
+            component.Colliding.Clear();
+            component.Colliding.UnionWith(state.Colliding);
+        }
 
         if (component.Colliding.Count > 0)
         {
-- 
2.52.0