Initial Commit

Common/UndoSystem/ActionStack.cs

@@ -0,0 +1,51 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Diagnostics;
+
+namespace Microsoft.Research.DynamicDataDisplay.Common.UndoSystem
+{
+	[DebuggerDisplay("Count = {Count}")]
+	public sealed class ActionStack
+	{
+		private readonly Stack<UndoAction> stack = new Stack<UndoAction>();
+
+		public void Push(UndoAction action)
+		{
+			stack.Push(action);
+
+			if (stack.Count == 1)
+				RaiseIsEmptyChanged();
+		}
+
+		public UndoAction Pop()
+		{
+			var action = stack.Pop();
+
+			if (stack.Count == 0)
+				RaiseIsEmptyChanged();
+
+			return action;
+		}
+
+		public int Count { get { return stack.Count; } }
+
+		public void Clear()
+		{
+			stack.Clear();
+			RaiseIsEmptyChanged();
+		}
+
+		public bool IsEmpty
+		{
+			get { return stack.Count == 0; }
+		}
+
+		private void RaiseIsEmptyChanged()
+		{
+			IsEmptyChanged.Raise(this);
+		}
+		public event EventHandler IsEmptyChanged;
+	}
+}