make more activities cancelable. remove many uses of CurrentActivity is T

OpenRA.Game/Traits/Activities/Drag.cs

@@ -8,7 +8,7 @@
  */
 #endregion
 
-using OpenRA.Traits;
+using System.Collections.Generic;
 
 namespace OpenRA.Traits.Activities
 {
@@ -48,5 +48,10 @@ namespace OpenRA.Traits.Activities
 			else
 				NextActivity = activity;
 		}
+
+		public IEnumerable<float2> GetCurrentPath()
+		{
+			yield return endLocation;
+		}
 	}
 }

OpenRA.Game/Traits/Activities/Idle.cs

@@ -10,19 +10,8 @@
 
 namespace OpenRA.Traits.Activities
 {
-	class Idle : IActivity
+	class Idle : CancelableActivity
 	{
-		IActivity NextActivity { get; set; }
-
-		public IActivity Tick(Actor self) { return NextActivity; }
-		public void Cancel(Actor self) {}
-
-		public void Queue( IActivity activity )
-		{
-			if( NextActivity != null )
-				NextActivity.Queue( activity );
-			else
-				NextActivity = activity;
-		}
+		public override IActivity Tick(Actor self) { return NextActivity; }
 	}
 }

OpenRA.Game/Traits/Activities/Move.cs

@@ -247,9 +247,17 @@ namespace OpenRA.Traits.Activities
 			return nextCell;
 		}
 
-		protected override void OnCancel()
+		protected override bool OnCancel()
 		{
 			path = new List<int2>();
+			return true;
+		}
+
+		public override IEnumerable<float2> GetCurrentPath()
+		{
+			if( path == null )
+				return new float2[ 0 ];
+			return Enumerable.Reverse(path).Select( c => Util.CenterOfCell(c) );
 		}
 
 		abstract class MovePart : IActivity
@@ -312,6 +320,11 @@ namespace OpenRA.Traits.Activities
 			}
 
 			protected abstract MovePart OnComplete( Actor self, Mobile mobile, Move parent );
+
+			public IEnumerable<float2> GetCurrentPath()
+			{
+				return move.GetCurrentPath();
+			}
 		}
 
 		class MoveFirstHalf : MovePart

OpenRA.Game/Traits/Activities/Sell.cs

@@ -8,6 +8,8 @@
  */
 #endregion
 
+using System.Collections.Generic;
+
 namespace OpenRA.Traits.Activities
 {
 	class Sell : IActivity
@@ -63,5 +65,10 @@ namespace OpenRA.Traits.Activities
 			else
 				NextActivity = activity;
 		}
+
+		public IEnumerable<float2> GetCurrentPath()
+		{
+			yield break;
+		}
 	}
 }

OpenRA.Game/Traits/Mobile.cs

@@ -321,14 +321,6 @@ namespace OpenRA.Traits
 			return Info.Speed * Info.TerrainSpeeds[type].Speed * modifier / 100f;
 		}
 		
-		public IEnumerable<float2> GetCurrentPath(Actor self)
-		{
-			var move = self.GetCurrentActivity() as Move;
-			if (move == null || move.path == null) return new float2[] { };
-			
-			return Enumerable.Reverse(move.path).Select( c => Util.CenterOfCell(c) );
-		}
-		
 		public void AddInfluence()
 		{
 			uim.Add( self, this );

OpenRA.Game/Traits/Selectable.cs

@@ -164,7 +164,7 @@ namespace OpenRA.Traits
 			if (mobile != null)
 			{
 				var alt = new float2(0, -mobile.Altitude);
-				var path = mobile.GetCurrentPath(self);
+				var path = self.GetCurrentActivity().GetCurrentPath();
 				var start = self.CenterLocation + alt;
 
 				var c = Color.Green;

OpenRA.Game/Traits/TraitsInterfaces.cs

@@ -113,7 +113,6 @@ namespace OpenRA.Traits
 	public interface IMove : ITeleportable
 	{
 		float MovementSpeedForCell(Actor self, int2 cell);
-		IEnumerable<float2> GetCurrentPath(Actor self);
 		int Altitude { get; set; }
 	}
 	
@@ -173,6 +172,7 @@ namespace OpenRA.Traits
 		IActivity Tick(Actor self);
 		void Cancel(Actor self);
 		void Queue(IActivity activity);
+		IEnumerable<float2> GetCurrentPath();
 	}
 
 	public abstract class CancelableActivity : IActivity
@@ -181,13 +181,15 @@ namespace OpenRA.Traits
 		protected bool IsCanceled { get; private set; }
 
 		public abstract IActivity Tick( Actor self );
-		protected virtual void OnCancel() {}
+		protected virtual bool OnCancel() { return true; }
 
 		public void Cancel( Actor self )
 		{
-			IsCanceled = true;
-			NextActivity = null;
-			OnCancel();
+			IsCanceled = OnCancel();
+			if( IsCanceled )
+				NextActivity = null;
+			else
+				NextActivity.Cancel( self );
 		}
 
 		public void Queue( IActivity activity )
@@ -197,6 +199,11 @@ namespace OpenRA.Traits
 			else
 				NextActivity = activity;
 		}
+
+		public virtual IEnumerable<float2> GetCurrentPath()
+		{
+			yield break;
+		}
 	}
 
 	public interface IRenderOverlay { void Render(); }