Add IReadOnlyList

OpenRA.Game/OpenRA.Game.csproj

@@ -244,6 +244,7 @@
     <Compile Include="Scripting\ScriptPlayerInterface.cs" />
     <Compile Include="Traits\Player\FixedColorPalette.cs" />
     <Compile Include="Primitives\ReadOnlyDictionary.cs" />
+    <Compile Include="Primitives\ReadOnlyList.cs" />
     <Compile Include="ModMetadata.cs" />
     <Compile Include="GameRules\Ruleset.cs" />
     <Compile Include="GameRules\RulesetCache.cs" />

OpenRA.Game/Primitives/ReadOnlyList.cs

@@ -0,0 +1,71 @@
+#region Copyright & License Information
+/*
+ * Copyright 2007-2014 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;
+using System.Collections.Generic;
+
+namespace OpenRA
+{
+	/// <summary>
+	/// A minimal read only list interface for .NET 4
+	/// </summary>
+	/// <remarks>
+	/// .NET 4.5 has an implementation built-in, this code is not meant to
+	/// duplicate it but provide a compatible interface that can be replaced
+	/// when we switch to .NET 4.5 or higher.
+	/// </remarks>
+	public interface IReadOnlyList<T> : IEnumerable<T>
+	{
+		int Count { get; }
+		T this[int index] { get; }
+	}
+
+	/// <summary>
+	/// A minimal read only list for .NET 4 implemented as a wrapper
+	/// around an IList.
+	/// </summary>
+	public class ReadOnlyList<T> : IReadOnlyList<T>
+	{
+		private readonly IList<T> list;
+
+		public ReadOnlyList()
+			: this(new List<T>())
+		{
+		}
+
+		public ReadOnlyList(IList<T> list)
+		{
+			if (list == null)
+				throw new ArgumentNullException("list");
+
+			this.list = list;
+		}
+
+		#region IEnumerable implementation
+		public IEnumerator<T> GetEnumerator()
+		{
+			return list.GetEnumerator();
+		}
+		#endregion
+
+		#region IEnumerable implementation
+		System.Collections.IEnumerator System.Collections.IEnumerable.GetEnumerator()
+		{
+			return list.GetEnumerator();
+		}
+		#endregion
+
+		#region IReadOnlyList implementation
+		public int Count { get { return list.Count; } }
+
+		public T this[int index] { get { return list[index]; } }
+		#endregion
+	}
+}