From 5b0cee78cf2b71e2de6ffa1fedd3b53118f77f11 Mon Sep 17 00:00:00 2001
From: Paul Chote <paul@chote.net>
Date: Sat, 19 Jul 2014 16:17:08 +1200
Subject: [PATCH] Calculate a new path (and possibly new target cell) if the
 original path is blocked.

---
 OpenRA.Mods.RA/Activities/MoveAdjacentTo.cs | 27 +++++++++++----------
 1 file changed, 14 insertions(+), 13 deletions(-)

diff --git a/OpenRA.Mods.RA/Activities/MoveAdjacentTo.cs b/OpenRA.Mods.RA/Activities/MoveAdjacentTo.cs
index 373f719ac2..23b0206a57 100755
--- a/OpenRA.Mods.RA/Activities/MoveAdjacentTo.cs
+++ b/OpenRA.Mods.RA/Activities/MoveAdjacentTo.cs
@@ -8,6 +8,7 @@
  */
 #endregion
 
+using System;
 using System.Collections.Generic;
 using System.Linq;
 using OpenRA.Mods.RA.Move;
@@ -17,6 +18,8 @@ namespace OpenRA.Mods.RA.Activities
 {
 	public class MoveAdjacentTo : Activity
 	{
+		static readonly List<CPos> NoPath = new List<CPos>();
+
 		readonly Mobile mobile;
 		readonly PathFinder pathFinder;
 		readonly DomainIndex domainIndex;
@@ -52,6 +55,11 @@ namespace OpenRA.Mods.RA.Activities
 			return targetPosition != oldTargetPosition;
 		}
 
+		protected virtual IEnumerable<CPos> CandidateMovementCells(Actor self)
+		{
+			return Util.AdjacentCells(self.World, target);
+		}
+
 		public override Activity Tick(Actor self)
 		{
 			var targetIsValid = target.IsValidFor(self);
@@ -65,7 +73,7 @@ namespace OpenRA.Mods.RA.Activities
 					return NextActivity;
 
 				// Target has moved, and MoveAdjacentTo is still valid.
-				UpdateInnerPath(self);
+				inner = mobile.MoveTo(() => CalculatePathToTarget(self));
 				repath = false;
 			}
 
@@ -97,12 +105,7 @@ namespace OpenRA.Mods.RA.Activities
 			return this;
 		}
 
-		protected virtual IEnumerable<CPos> CandidateMovementCells(Actor self)
-		{
-			return Util.AdjacentCells(self.World, target);
-		}
-
-		void UpdateInnerPath(Actor self)
+		List<CPos> CalculatePathToTarget(Actor self)
 		{
 			var targetCells = CandidateMovementCells(self);
 			var searchCells = new List<CPos>();
@@ -113,14 +116,12 @@ namespace OpenRA.Mods.RA.Activities
 					searchCells.Add(cell);
 
 			if (!searchCells.Any())
-				return;
+				return NoPath;
 
-			var path = pathFinder.FindBidiPath(
-				PathSearch.FromPoints(self.World, mobile.Info, self, searchCells, loc, true),
-				PathSearch.FromPoint(self.World, mobile.Info, self, loc, targetPosition, true).Reverse()
-			);
+			var fromSrc = PathSearch.FromPoints(self.World, mobile.Info, self, searchCells, loc, true);
+			var fromDest = PathSearch.FromPoint(self.World, mobile.Info, self, loc, targetPosition, true).Reverse();
 
-			inner = mobile.MoveTo(() => path);
+			return pathFinder.FindBidiPath(fromSrc, fromDest);
 		}
 
 		public override IEnumerable<Target> GetTargets(Actor self)