reintroduce Cached<T>; use for Actor.Bounds, Actor.ExtendedBounds, which replace Actor.GetBounds(bool)

OpenRA.FileFormats/OpenRA.FileFormats.csproj

@@ -114,6 +114,7 @@
     <Compile Include="FileFormats\Blast.cs" />
     <Compile Include="Filesystem\ZipFile.cs" />
     <Compile Include="InstallUtils.cs" />
+    <Compile Include="Primitives\Cached.cs" />
   </ItemGroup>
   <Import Project="$(MSBuildBinPath)\Microsoft.CSharp.targets" />
   <!-- To modify your build process, add your task inside one of the targets below and uncomment it. 
@@ -123,4 +124,4 @@
   <Target Name="AfterBuild">
   </Target>
   -->
-</Project>
+</Project>

OpenRA.FileFormats/Primitives/Cached.cs

@@ -0,0 +1,60 @@
+#region Copyright & License Information
+/*
+ * Copyright 2007-2011 The OpenRA Developers (see AUTHORS)
+ * This file is part of OpenRA, which is free software. It is made 
+ * available to you under the terms of the GNU General Public License
+ * as published by the Free Software Foundation. For more information,
+ * see COPYING.
+ */
+#endregion
+
+using System;
+
+namespace OpenRA.FileFormats
+{
+	public class Cached<T>
+	{
+		Func<T> p;
+		T value;
+		bool hasValue;
+
+		public Cached(Func<T> p)
+		{
+			if (p == null)
+				throw new ArgumentNullException();
+
+			this.p = p;
+		}
+
+		public T Value
+		{
+			get
+			{
+				if (hasValue)
+					return value;
+
+				value = p();
+				hasValue = true;
+				return value;
+			}
+		}
+
+        public void Force()
+        {
+            #pragma warning disable 0168
+			var ignored = Value;
+			#pragma warning restore 0168
+        }
+		
+		public void Invalidate()
+		{
+			hasValue = false;
+		}
+	}
+
+	public static class Cached
+	{
+		public static Cached<T> New<T>(Func<T> p) { return new Cached<T>(p); }
+	}
+}
+