Improve BotModule performance.

Several parts of bot module logic, often through the AIUtils helper class, will query or count over all actors in the world. This is not a fast operation and the AI tends to repeat it often.

Introduce some ActorIndex classes that can maintain an index of actors in the world that match a query based on a mix of actor name, owner or trait. These indexes introduce some overhead to maintain, but allow the queries or counts that bot modules needs to perform to be greatly sped up, as the index means there is a much smaller starting set of actors to consider. This is beneficial to the bot logic as the TraitDictionary index maintained by the world works only in terms of traits and doesn't allow the bot logic to perform a sufficiently selective lookup. This is because the bot logic is usually defined in terms of actor names rather than traits.

OpenRA.Mods.Common/Traits/BotModules/UnitBuilderBotModule.cs

@@ -44,7 +44,8 @@ namespace OpenRA.Mods.Common.Traits
 		public override object Create(ActorInitializer init) { return new UnitBuilderBotModule(init.Self, this); }
 	}
 
-	public class UnitBuilderBotModule : ConditionalTrait<UnitBuilderBotModuleInfo>, IBotTick, IBotNotifyIdleBaseUnits, IBotRequestUnitProduction, IGameSaveTraitData
+	public class UnitBuilderBotModule : ConditionalTrait<UnitBuilderBotModuleInfo>,
+		IBotTick, IBotNotifyIdleBaseUnits, IBotRequestUnitProduction, IGameSaveTraitData, INotifyActorDisposing
 	{
 		public const int FeedbackTime = 30; // ticks; = a bit over 1s. must be >= netlag.
 
@@ -52,6 +53,7 @@ namespace OpenRA.Mods.Common.Traits
 		readonly Player player;
 
 		readonly List<string> queuedBuildRequests = new();
+		readonly ActorIndex.OwnerAndNames unitsToBuild;
 
 		IBotRequestPauseUnitProduction[] requestPause;
 		int idleUnitCount;
@@ -65,6 +67,7 @@ namespace OpenRA.Mods.Common.Traits
 		{
 			world = self.World;
 			player = self.Owner;
+			unitsToBuild = new ActorIndex.OwnerAndNames(world, info.UnitsToBuild.Keys, player);
 		}
 
 		protected override void Created(Actor self)
@@ -174,20 +177,21 @@ namespace OpenRA.Mods.Common.Traits
 			if (buildableThings.Length == 0)
 				return null;
 
-			var allUnits = world.Actors.Where(a => a.Owner == player && Info.UnitsToBuild.ContainsKey(a.Info.Name) && !a.IsDead).ToArray();
+			var allUnits = unitsToBuild.Actors.Where(a => !a.IsDead).ToArray();
 
 			ActorInfo desiredUnit = null;
 			var desiredError = int.MaxValue;
 			foreach (var unit in buildableThings)
 			{
-				if (!Info.UnitsToBuild.ContainsKey(unit.Name) || (Info.UnitDelays != null && Info.UnitDelays.TryGetValue(unit.Name, out var delay) && delay > world.WorldTick))
+				if (!Info.UnitsToBuild.TryGetValue(unit.Name, out var share) ||
+					(Info.UnitDelays != null && Info.UnitDelays.TryGetValue(unit.Name, out var delay) && delay > world.WorldTick))
 					continue;
 
 				var unitCount = allUnits.Count(a => a.Info.Name == unit.Name);
 				if (Info.UnitLimits != null && Info.UnitLimits.TryGetValue(unit.Name, out var count) && unitCount >= count)
 					continue;
 
-				var error = allUnits.Length > 0 ? unitCount * 100 / allUnits.Length - Info.UnitsToBuild[unit.Name] : -1;
+				var error = allUnits.Length > 0 ? unitCount * 100 / allUnits.Length - share : -1;
 				if (error < 0)
 					return HasAdequateAirUnitReloadBuildings(unit) ? unit : null;
 
@@ -213,8 +217,8 @@ namespace OpenRA.Mods.Common.Traits
 			if (rearmableInfo == null)
 				return true;
 
-			var countOwnAir = AIUtils.CountActorsWithTrait<IPositionable>(actorInfo.Name, player);
-			var countBuildings = rearmableInfo.RearmActors.Sum(b => AIUtils.CountActorsWithTrait<Building>(b, player));
+			var countOwnAir = AIUtils.CountActorsWithNameAndTrait<IPositionable>(actorInfo.Name, player);
+			var countBuildings = rearmableInfo.RearmActors.Sum(b => AIUtils.CountActorsWithNameAndTrait<Building>(b, player));
 			if (countOwnAir >= countBuildings)
 				return false;
 
@@ -249,5 +253,10 @@ namespace OpenRA.Mods.Common.Traits
 			if (idleUnitCountNode != null)
 				idleUnitCount = FieldLoader.GetValue<int>("IdleUnitCount", idleUnitCountNode.Value.Value);
 		}
+
+		void INotifyActorDisposing.Disposing(Actor self)
+		{
+			unitsToBuild.Dispose();
+		}
 	}
 }