Block some subfloor anchor attempts (#6765)

Content.Server/SubFloor/SubFloorHideSystem.cs

@@ -1,7 +1,34 @@
+using Content.Server.Construction.Components;
 using Content.Shared.SubFloor;
 
 namespace Content.Server.SubFloor;
 
 public sealed class SubFloorHideSystem : SharedSubFloorHideSystem
 {
+    public override void Initialize()
+    {
+        base.Initialize();
+        SubscribeLocalEvent<SubFloorHideComponent, AnchorAttemptEvent>(OnAnchorAttempt);
+        SubscribeLocalEvent<SubFloorHideComponent, UnanchorAttemptEvent>(OnUnanchorAttempt);
+    }
+
+    private void OnAnchorAttempt(EntityUid uid, SubFloorHideComponent component, AnchorAttemptEvent args)
+    {
+        // No teleporting entities through floor tiles when anchoring them.
+        var xform = Transform(uid);
+
+        if (MapManager.TryGetGrid(xform.GridID, out var grid)
+            && HasFloorCover(grid, grid.TileIndicesFor(xform.Coordinates)))
+        {
+            args.Cancel();
+        }
+    }
+
+    private void OnUnanchorAttempt(EntityUid uid, SubFloorHideComponent component, UnanchorAttemptEvent args)
+    {
+        // No un-anchoring things under the floor. Only required for something like vents, which are still interactable
+        // despite being partially under the floor.
+        if (component.IsUnderCover)
+            args.Cancel();
+    }
 }