Add INotify(Activity)StanceChanged interfaces.

OpenRA.Game/Activities/Activity.cs

@@ -171,6 +171,20 @@ namespace OpenRA.Activities
 				act = act.childActivity;
 			}
 		}
+
+		public IEnumerable<T> ActivitiesImplementing<T>() where T : IActivityInterface
+		{
+			if (childActivity != null)
+				foreach (var a in childActivity.ActivitiesImplementing<T>())
+					yield return a;
+
+			if (this is T)
+				yield return (T)(object)this;
+
+			if (NextActivity != null)
+				foreach (var a in NextActivity.ActivitiesImplementing<T>())
+					yield return a;
+		}
 	}
 
 	public static class ActivityExts

OpenRA.Game/Traits/TraitsInterfaces.cs

@@ -350,6 +350,8 @@ namespace OpenRA.Traits
 	[SuppressMessage("StyleCop.CSharp.NamingRules", "SA1302:InterfaceNamesMustBeginWithI", Justification = "Not a real interface, but more like a tag.")]
 	public interface Requires<T> where T : class, ITraitInfoInterface { }
 
+	public interface IActivityInterface { }
+
 	[RequireExplicitImplementation]
 	public interface INotifySelected { void Selected(Actor self); }
 	[RequireExplicitImplementation]

OpenRA.Mods.Common/Traits/AutoTarget.cs

@@ -11,6 +11,7 @@
 
 using System.Collections.Generic;
 using System.Linq;
+using OpenRA.Activities;
 using OpenRA.Primitives;
 using OpenRA.Traits;
 
@@ -18,6 +19,18 @@ namespace OpenRA.Mods.Common.Traits
 {
 	public enum UnitStance { HoldFire, ReturnFire, Defend, AttackAnything }
 
+	[RequireExplicitImplementation]
+	public interface IActivityNotifyStanceChanged : IActivityInterface
+	{
+		void StanceChanged(Actor self, AutoTarget autoTarget, UnitStance oldStance, UnitStance newStance);
+	}
+
+	[RequireExplicitImplementation]
+	public interface INotifyStanceChanged
+	{
+		void StanceChanged(Actor self, AutoTarget autoTarget, UnitStance oldStance, UnitStance newStance);
+	}
+
 	[Desc("The actor will automatically engage the enemy when it is in range.")]
 	public class AutoTargetInfo : ConditionalTraitInfo, Requires<AttackBaseInfo>, IEditorActorOptions
 	{
@@ -126,6 +139,7 @@ namespace OpenRA.Mods.Common.Traits
 		UnitStance stance;
 		ConditionManager conditionManager;
 		IDisableAutoTarget[] disableAutoTarget;
+		INotifyStanceChanged[] notifyStanceChanged;
 		IEnumerable<AutoTargetPriorityInfo> activeTargetPriorities;
 		int conditionToken = ConditionManager.InvalidConditionToken;
 
@@ -134,8 +148,16 @@ namespace OpenRA.Mods.Common.Traits
 			if (stance == value)
 				return;
 
+			var oldStance = stance;
 			stance = value;
 			ApplyStanceCondition(self);
+
+			foreach (var nsc in notifyStanceChanged)
+				nsc.StanceChanged(self, this, oldStance, stance);
+
+			if (self.CurrentActivity != null)
+				foreach (var a in self.CurrentActivity.ActivitiesImplementing<IActivityNotifyStanceChanged>())
+					a.StanceChanged(self, this, oldStance, stance);
 		}
 
 		void ApplyStanceCondition(Actor self)
@@ -176,6 +198,7 @@ namespace OpenRA.Mods.Common.Traits
 
 			conditionManager = self.TraitOrDefault<ConditionManager>();
 			disableAutoTarget = self.TraitsImplementing<IDisableAutoTarget>().ToArray();
+			notifyStanceChanged = self.TraitsImplementing<INotifyStanceChanged>().ToArray();
 			ApplyStanceCondition(self);
 		}