(svn r4937) Reduce the use of _error_message a bit

4 files changed, 13 insertions, 17 deletions

diff --git a/rail_cmd.c b/rail_cmd.c
index 203f83119..ec819ab36 100644
--- a/rail_cmd.c
+++ b/rail_cmd.c
@@ -904,6 +904,7 @@ int32 CmdConvertRail(TileIndex tile, uint32 flags, uint32 p1, uint32 p2)
 
 	money = GetAvailableMoneyForCommand();
 	cost = 0;
+	ret = 0;
 
 	for (x = sx; x <= ex; ++x) {
 		for (y = sy; y <= ey; ++y) {
@@ -933,7 +934,7 @@ int32 CmdConvertRail(TileIndex tile, uint32 flags, uint32 p1, uint32 p2)
 		}
 	}
 
-	return (cost == 0) ? CMD_ERROR : cost;
+	return (cost == 0) ? ret : cost;
 }
 
 static int32 RemoveTrainDepot(TileIndex tile, uint32 flags)
diff --git a/tunnelbridge_cmd.c b/tunnelbridge_cmd.c
index 858465aaa..c3c339bdd 100644
--- a/tunnelbridge_cmd.c
+++ b/tunnelbridge_cmd.c
@@ -656,10 +656,7 @@ static int32 DoClearBridge(TileIndex tile, uint32 flags)
 		endtile - delta,
 		GetBridgeHeightRamp(tile) + TILE_HEIGHT
 	);
-	if (v != NULL) {
-		VehicleInTheWayErrMsg(v);
-		return CMD_ERROR;
-	}
+	if (v != NULL) return_cmd_error(VehicleInTheWayErrMsg(v));
 
 	t = ClosestTownFromTile(tile, (uint)-1); //needed for town rating penalty
 	// check if you're allowed to remove the bridge owned by a town.
@@ -770,13 +767,11 @@ int32 DoConvertTunnelBridgeRail(TileIndex tile, RailType totype, bool exec)
 		// Make sure there's no vehicle on the bridge
 		v = FindVehicleBetween(tile, endtile, z);
 		if (v != NULL) {
-			VehicleInTheWayErrMsg(v);
-			return CMD_ERROR;
+			return_cmd_error(VehicleInTheWayErrMsg(v));
 		}
 
 		if (!EnsureNoVehicle(tile) || !EnsureNoVehicle(endtile)) {
-			_error_message = STR_8803_TRAIN_IN_THE_WAY;
-			return CMD_ERROR;
+			return_cmd_error(STR_8803_TRAIN_IN_THE_WAY);
 		}
 
 		if (GetRailType(tile) == totype) return CMD_ERROR;
diff --git a/vehicle.c b/vehicle.c
index 63d861129..eed5b2128 100644
--- a/vehicle.c
+++ b/vehicle.c
@@ -102,13 +102,13 @@ bool VehicleNeedsService(const Vehicle *v)
 		(v->date_of_last_service + v->service_interval < _date);
 }
 
-void VehicleInTheWayErrMsg(const Vehicle* v)
+StringID VehicleInTheWayErrMsg(const Vehicle* v)
 {
 	switch (v->type) {
-		case VEH_Train:    _error_message = STR_8803_TRAIN_IN_THE_WAY;        break;
-		case VEH_Road:     _error_message = STR_9000_ROAD_VEHICLE_IN_THE_WAY; break;
-		case VEH_Aircraft: _error_message = STR_A015_AIRCRAFT_IN_THE_WAY;     break;
-		default:           _error_message = STR_980E_SHIP_IN_THE_WAY;         break;
+		case VEH_Train:    return STR_8803_TRAIN_IN_THE_WAY;
+		case VEH_Road:     return STR_9000_ROAD_VEHICLE_IN_THE_WAY;
+		case VEH_Aircraft: return STR_A015_AIRCRAFT_IN_THE_WAY;
+		default:           return STR_980E_SHIP_IN_THE_WAY;
 	}
 }
 
@@ -117,7 +117,7 @@ static void *EnsureNoVehicleProc(Vehicle *v, void *data)
 	if (v->tile != *(const TileIndex*)data || v->type == VEH_Disaster)
 		return NULL;
 
-	VehicleInTheWayErrMsg(v);
+	_error_message = VehicleInTheWayErrMsg(v);
 	return v;
 }
 
@@ -133,7 +133,7 @@ static void *EnsureNoVehicleProcZ(Vehicle *v, void *data)
 	if (v->tile != ti->tile || v->type == VEH_Disaster) return NULL;
 	if (v->z_pos > ti->z) return NULL;
 
-	VehicleInTheWayErrMsg(v);
+	_error_message = VehicleInTheWayErrMsg(v);
 	return v;
 }
 
diff --git a/vehicle.h b/vehicle.h
index a4939c69e..5d22820be 100644
--- a/vehicle.h
+++ b/vehicle.h
@@ -284,7 +284,7 @@ Vehicle *CreateEffectVehicleRel(const Vehicle *v, int x, int y, int z, EffectVeh
 
 uint32 VehicleEnterTile(Vehicle *v, TileIndex tile, int x, int y);
 
-void VehicleInTheWayErrMsg(const Vehicle* v);
+StringID VehicleInTheWayErrMsg(const Vehicle* v);
 Vehicle *FindVehicleBetween(TileIndex from, TileIndex to, byte z);
 TileIndex GetVehicleOutOfTunnelTile(const Vehicle *v);