From 39ce915157bcf40ee272342071e678c47d8f5a8a Mon Sep 17 00:00:00 2001
From: Kenneth Loeffler <kenloef@gmail.com>
Date: Tue, 30 May 2023 13:38:24 -0700
Subject: [PATCH] Use an iterative implementation for Instance::clone_inner

---
 packages/lib-roblox/src/instance/mod.rs | 30 ++++++++++++++++++-------
 1 file changed, 22 insertions(+), 8 deletions(-)

diff --git a/packages/lib-roblox/src/instance/mod.rs b/packages/lib-roblox/src/instance/mod.rs
index 0eb302f..7a1073a 100644
--- a/packages/lib-roblox/src/instance/mod.rs
+++ b/packages/lib-roblox/src/instance/mod.rs
@@ -214,9 +214,11 @@ impl Instance {
         parent_ref: DomRef,
         reference_map: &mut HashMap<DomRef, DomRef>,
     ) -> DomRef {
-        // NOTE: We create a new scope here to avoid deadlocking since
-        // our clone implementation must have exclusive write access
-        let (new_ref, child_refs) = {
+        fn do_clone(
+            dom_ref: DomRef,
+            parent_ref: DomRef,
+            reference_map: &mut HashMap<DomRef, DomRef>,
+        ) -> (DomRef, Vec<DomRef>) {
             let mut dom = INTERNAL_DOM
                 .try_write()
                 .expect("Failed to get write access to document");
@@ -243,13 +245,25 @@ impl Instance {
             reference_map.insert(dom_ref, new_ref);
 
             (new_ref, child_refs)
-        };
-
-        for child_ref in child_refs {
-            Self::clone_inner(child_ref, new_ref, reference_map);
         }
 
-        new_ref
+        let (cloned_parent, uncloned_children) = do_clone(dom_ref, parent_ref, reference_map);
+        let mut queue = VecDeque::with_capacity(uncloned_children.len());
+
+        for uncloned_child in uncloned_children.iter() {
+            queue.push_back((cloned_parent, *uncloned_child));
+        }
+
+        while let Some((cloned_parent, uncloned_child)) = queue.pop_front() {
+            let (cloned_parent, uncloned_children) =
+                do_clone(uncloned_child, cloned_parent, reference_map);
+
+            for uncloned_child in uncloned_children.iter() {
+                queue.push_back((*uncloned_child, cloned_parent))
+            }
+        }
+
+        cloned_parent
     }
 
     /**