(&mut self, node: &NodeRef<K, V>, key: &K)
| 65 | /// Recursively remove a key with proper arena access. |
| 66 | #[inline] |
| 67 | fn remove_recursive(&mut self, node: &NodeRef<K, V>, key: &K) -> RemoveResult<V> { |
| 68 | match node { |
| 69 | NodeRef::Leaf(id, _) => { |
| 70 | self.get_leaf_mut(*id) |
| 71 | .map_or(RemoveResult::Updated(None, false), |leaf| { |
| 72 | let (removed_value, is_underfull) = leaf.remove(key); |
| 73 | RemoveResult::Updated(removed_value, is_underfull) |
| 74 | }) |
| 75 | } |
| 76 | NodeRef::Branch(id, _) => { |
| 77 | let id = *id; |
| 78 | |
| 79 | // First get child info without mutable borrow |
| 80 | let (child_index, child_ref) = match self.get_child_for_key(id, key) { |
| 81 | Some(info) => info, |
| 82 | None => return RemoveResult::Updated(None, false), |
| 83 | }; |
| 84 | |
| 85 | // Recursively remove |
| 86 | let child_result = self.remove_recursive(&child_ref, key); |
| 87 | |
| 88 | // Handle the result |
| 89 | match child_result { |
| 90 | RemoveResult::Updated(removed_value, child_became_underfull) => { |
| 91 | // If child became underfull, try to rebalance |
| 92 | if removed_value.is_some() && child_became_underfull { |
| 93 | let _child_still_exists = self.rebalance_child(id, child_index); |
| 94 | } |
| 95 | |
| 96 | // Only compute underfull if a removal actually happened |
| 97 | let is_underfull = if removed_value.is_some() { |
| 98 | self.is_node_underfull(&NodeRef::Branch(id, PhantomData)) |
| 99 | } else { |
| 100 | false |
| 101 | }; |
| 102 | RemoveResult::Updated(removed_value, is_underfull) |
| 103 | } |
| 104 | } |
| 105 | } |
| 106 | } |
| 107 | } |
| 108 | |
| 109 | /// Collapse the root if it's a branch with only one child or no children. |
| 110 | fn collapse_root_if_needed(&mut self) { |
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