Store Targetables in Actor.

This can be used to avoid several lookups for these traits, as well as allow Actor to provide specialised methods to deal with target types efficiently. This also reduces some code duplication.

OpenRA.Game/Actor.cs

@@ -44,6 +44,7 @@ namespace OpenRA
 		public Rectangle VisualBounds { get; private set; }
 		public IEffectiveOwner EffectiveOwner { get; private set; }
 		public IOccupySpace OccupiesSpace { get; private set; }
+		public ITargetable[] Targetables { get; private set; }
 
 		public bool IsIdle { get { return currentActivity == null; } }
 		public bool IsDead { get { return Disposed || (health != null && health.IsDead); } }
@@ -107,6 +108,7 @@ namespace OpenRA
 			disables = TraitsImplementing<IDisable>().ToArray();
 			visibilityModifiers = TraitsImplementing<IVisibilityModifier>().ToArray();
 			defaultVisibility = Trait<IDefaultVisibility>();
+			Targetables = TraitsImplementing<ITargetable>().ToArray();
 		}
 
 		Rectangle DetermineBounds()
@@ -320,6 +322,30 @@ namespace OpenRA
 			return defaultVisibility.IsVisible(this, player);
 		}
 
+		public IEnumerable<string> GetAllTargetTypes()
+		{
+			foreach (var targetable in Targetables)
+				foreach (var targetType in targetable.TargetTypes)
+					yield return targetType;
+		}
+
+		public IEnumerable<string> GetEnabledTargetTypes()
+		{
+			foreach (var targetable in Targetables)
+				if (targetable.IsTraitEnabled())
+					foreach (var targetType in targetable.TargetTypes)
+						yield return targetType;
+		}
+
+		public bool IsTargetableBy(Actor byActor)
+		{
+			foreach (var targetable in Targetables)
+				if (targetable.IsTraitEnabled() && targetable.TargetableBy(this, byActor))
+					return true;
+
+			return false;
+		}
+
 		#region Scripting interface
 
 		Lazy<ScriptActorInterface> luaInterface;