Allow custom prerequisites to be restricted by race.

OpenRA.Mods.RA/Player/ProvidesCustomPrerequisite.cs

@@ -0,0 +1,77 @@
+#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.Collections.Generic;
+using System.Linq;
+using OpenRA.Primitives;
+using OpenRA.Traits;
+
+namespace OpenRA.Mods.RA
+{
+	public class ProvidesCustomPrerequisiteInfo : ITraitInfo
+	{
+		[Desc("The prerequisite type that this provides")]
+		public readonly string Prerequisite = null;
+
+		[Desc("Only grant this prerequisite for certain factions")]
+		public readonly string[] Race = { };
+
+		[Desc("Should the prerequisite remain enabled if the owner changes?")]
+		public readonly bool Sticky = true;
+		public object Create(ActorInitializer init) { return new ProvidesCustomPrerequisite(init, this); }
+	}
+
+	public class ProvidesCustomPrerequisite : ITechTreePrerequisite, INotifyOwnerChanged
+	{
+		ProvidesCustomPrerequisiteInfo info;
+		bool enabled = true;
+
+		public ProvidesCustomPrerequisite(ActorInitializer init, ProvidesCustomPrerequisiteInfo info)
+		{
+			this.info = info;
+
+			if (info.Race.Any())
+			{
+				var race = init.self.Owner.Country.Race;
+				if (init.Contains<RaceInit>())
+					race = init.Get<RaceInit, string>();
+
+				enabled = info.Race.Contains(race);
+			}
+		}
+
+		public IEnumerable<string> ProvidesPrerequisites
+		{
+			get
+			{
+				if (!enabled)
+					yield break;
+
+				yield return info.Prerequisite;
+			}
+		}
+
+		public void OnOwnerChanged(Actor self, Player oldOwner, Player newOwner)
+		{
+			if (!info.Sticky && info.Race.Any())
+				enabled = info.Race.Contains(self.Owner.Country.Race);
+		}
+	}
+
+	// Allows maps / transformations to specify the race variant of an actor.
+	public class RaceInit : IActorInit<string>
+	{
+		[FieldFromYamlKey] public readonly string Race;
+
+		public RaceInit() { }
+		public RaceInit(string race) { Race = race; }
+		public string Value(World world) { return Race; }
+	}
+}