1 files changed, 44 insertions, 0 deletions
diff --git a/editor/txmgr/TransactionStack.h b/editor/txmgr/TransactionStack.h
new file mode 100644
index 0000000000..74e8aebec8
--- /dev/null
+++ b/editor/txmgr/TransactionStack.h
@@ -0,0 +1,44 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* 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_TransactionStack_h
+#define mozilla_TransactionStack_h
+
+#include "mozilla/AlreadyAddRefed.h"
+#include "nsDeque.h"
+
+class nsCycleCollectionTraversalCallback;
+
+namespace mozilla {
+
+class TransactionItem;
+
+class TransactionStack : private nsRefPtrDeque<TransactionItem> {
+ public:
+  enum Type { FOR_UNDO, FOR_REDO };
+
+  explicit TransactionStack(Type aType);
+  ~TransactionStack();
+
+  void Push(TransactionItem* aTransactionItem);
+  void Push(already_AddRefed<TransactionItem> aTransactionItem);
+  already_AddRefed<TransactionItem> Pop();
+  already_AddRefed<TransactionItem> PopBottom();
+  already_AddRefed<TransactionItem> Peek() const;
+  already_AddRefed<TransactionItem> GetItemAt(size_t aIndex) const;
+  void Clear();
+  size_t GetSize() const { return nsRefPtrDeque<TransactionItem>::GetSize(); }
+  bool IsEmpty() const { return GetSize() == 0; }
+
+  void DoUnlink() { Clear(); }
+  void DoTraverse(nsCycleCollectionTraversalCallback& cb);
+
+ private:
+  const Type mType;
+};
+
+}  // namespace mozilla
+
+#endif  // mozilla_TransactionStack_h