1 files changed, 63 insertions, 0 deletions
diff --git a/dom/base/nsChildContentList.h b/dom/base/nsChildContentList.h
new file mode 100644
index 0000000000..96c4e0eff1
--- /dev/null
+++ b/dom/base/nsChildContentList.h
@@ -0,0 +1,63 @@
+/* -*- 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 nsChildContentList_h__
+#define nsChildContentList_h__
+
+#include "nsISupportsImpl.h"
+#include "nsINodeList.h"            // base class
+#include "js/TypeDecls.h"     // for Handle, Value, JSObject, JSContext
+
+class nsIContent;
+class nsINode;
+
+/**
+ * Class that implements the nsIDOMNodeList interface (a list of children of
+ * the content), by holding a reference to the content and delegating GetLength
+ * and Item to its existing child list.
+ * @see nsIDOMNodeList
+ */
+class nsChildContentList final : public nsINodeList
+{
+public:
+  explicit nsChildContentList(nsINode* aNode)
+    : mNode(aNode)
+  {
+  }
+
+  NS_DECL_CYCLE_COLLECTING_ISUPPORTS
+  NS_DECL_CYCLE_COLLECTION_SKIPPABLE_SCRIPT_HOLDER_CLASS(nsChildContentList)
+
+  // nsWrapperCache
+  virtual JSObject* WrapObject(JSContext *cx, JS::Handle<JSObject*> aGivenProto) override;
+
+  // nsIDOMNodeList interface
+  NS_DECL_NSIDOMNODELIST
+
+  // nsINodeList interface
+  virtual int32_t IndexOf(nsIContent* aContent) override;
+  virtual nsIContent* Item(uint32_t aIndex) override;
+
+  void DropReference()
+  {
+    mNode = nullptr;
+  }
+
+  virtual nsINode* GetParentObject() override
+  {
+    return mNode;
+  }
+
+private:
+  ~nsChildContentList() {}
+
+  // The node whose children make up the list.
+  // This is a non-owning ref which is safe because it's set to nullptr by
+  // DropReference() by the node slots get destroyed.
+  nsINode* MOZ_NON_OWNING_REF mNode;
+};
+
+#endif /* nsChildContentList_h__ */