1 files changed, 49 insertions, 0 deletions
diff --git a/dom/base/TreeOrderedArrayInlines.h b/dom/base/TreeOrderedArrayInlines.h
new file mode 100644
index 0000000000..a250e8ec43
--- /dev/null
+++ b/dom/base/TreeOrderedArrayInlines.h
@@ -0,0 +1,49 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef mozilla_dom_TreeOrderedArrayInlines_h
+#define mozilla_dom_TreeOrderedArrayInlines_h
+
+#include "mozilla/dom/TreeOrderedArray.h"
+#include "mozilla/BinarySearch.h"
+#include "nsContentUtils.h"
+#include <type_traits>
+
+namespace mozilla::dom {
+
+template <typename Node>
+size_t TreeOrderedArray<Node>::Insert(Node& aNode, nsINode* aCommonAncestor) {
+  static_assert(std::is_base_of_v<nsINode, Node>, "Should be a node");
+
+  if (mList.IsEmpty()) {
+    mList.AppendElement(&aNode);
+    return 0;
+  }
+
+  struct PositionComparator {
+    Node& mNode;
+    nsINode* mCommonAncestor;
+    PositionComparator(Node& aNode, nsINode* aCommonAncestor)
+        : mNode(aNode), mCommonAncestor(aCommonAncestor) {}
+
+    int operator()(void* aNode) const {
+      auto* curNode = static_cast<Node*>(aNode);
+      MOZ_DIAGNOSTIC_ASSERT(curNode != &mNode,
+                            "Tried to insert a node already in the list");
+      return nsContentUtils::CompareTreePosition<TreeKind::DOM>(
+          &mNode, curNode, mCommonAncestor);
+    }
+  };
+
+  size_t idx;
+  BinarySearchIf(mList, 0, mList.Length(),
+                 PositionComparator(aNode, aCommonAncestor), &idx);
+  mList.InsertElementAt(idx, &aNode);
+  return idx;
+}
+
+}  // namespace mozilla::dom
+#endif