(svn r16746) -Codechange: use Town::PostDestructor() instead of not very clean construct for invalidating nearest town for road tiles

src/road_cmd.cpp

@@ -1248,7 +1248,7 @@ void DrawRoadDepotSprite(int x, int y, DiagDirection dir, RoadType rt)
  * @param ignore town that should be ignored (because we are deleting it now)
  * @pre invalidate == true implies _generating_world == true
  */
-void UpdateNearestTownForRoadTiles(bool invalidate, const Town *ignore)
+void UpdateNearestTownForRoadTiles(bool invalidate)
 {
 	assert(!invalidate || _generating_world);
 
@@ -1256,7 +1256,7 @@ void UpdateNearestTownForRoadTiles(bool invalidate, const Town *ignore)
 		if (IsTileType(t, MP_ROAD) && !HasTownOwnedRoad(t)) {
 			TownID tid = (TownID)INVALID_TOWN;
 			if (!invalidate) {
-				const Town *town = CalcClosestTownFromTile(t, UINT_MAX, ignore);
+				const Town *town = CalcClosestTownFromTile(t);
 				if (town != NULL) tid = town->index;
 			}
 			SetTownIndex(t, tid);

src/road_cmd.h

@@ -8,6 +8,6 @@
 #include "direction_type.h"
 
 void DrawRoadDepotSprite(int x, int y, DiagDirection dir, RoadType rt);
-void UpdateNearestTownForRoadTiles(bool invalidate, const struct Town *ignore = NULL);
+void UpdateNearestTownForRoadTiles(bool invalidate);
 
 #endif /* ROAD_CMD_H */

src/town.h

@@ -142,6 +142,7 @@ struct Town : TownPool::PoolItem<&_town_pool> {
 	}
 
 	static Town *GetRandom();
+	static void PostDestructor(size_t index);
 };
 
 uint32 GetWorldPopulation();
@@ -181,7 +182,7 @@ bool CheckforTownRating(DoCommandFlag flags, Town *t, TownRatingCheckType type);
 
 TileIndexDiff GetHouseNorthPart(HouseID &house);
 
-Town *CalcClosestTownFromTile(TileIndex tile, uint threshold = UINT_MAX, const Town *ignore = NULL);
+Town *CalcClosestTownFromTile(TileIndex tile, uint threshold = UINT_MAX);
 
 #define FOR_ALL_TOWNS_FROM(var, start) FOR_ALL_ITEMS_FROM(Town, town_index, var, start)
 #define FOR_ALL_TOWNS(var) FOR_ALL_TOWNS_FROM(var, 0)

src/town_cmd.cpp

@@ -102,8 +102,17 @@ Town::~Town()
 	DeleteSubsidyWithTown(this->index);
 
 	MarkWholeScreenDirty();
+}
+
 
-	UpdateNearestTownForRoadTiles(false, this);
+/**
+ * Invalidating of the "nearest town cache" has to be done
+ * after removing item from the pool.
+ * @param index index of deleted item
+ */
+void Town::PostDestructor(size_t index)
+{
+	UpdateNearestTownForRoadTiles(false);
 }
 
 /**
@@ -2694,14 +2703,13 @@ bool CheckIfAuthorityAllowsNewStation(TileIndex tile, DoCommandFlag flags)
 }
 
 
-Town *CalcClosestTownFromTile(TileIndex tile, uint threshold, const Town *ignore)
+Town *CalcClosestTownFromTile(TileIndex tile, uint threshold)
 {
 	Town *t;
 	uint best = threshold;
 	Town *best_town = NULL;
 
 	FOR_ALL_TOWNS(t) {
-		if (t == ignore) continue;
 		uint dist = DistanceManhattan(tile, t->xy);
 		if (dist < best) {
 			best = dist;