(svn r19561) -Feature: Give more detailed error message when trying to build a too long bridge.

src/bridge.h

@@ -67,7 +67,7 @@ static inline const BridgeSpec *GetBridgeSpec(BridgeType i)
 
 void DrawBridgeMiddle(const TileInfo *ti);
 
-bool CheckBridgeAvailability(BridgeType bridge_type, uint bridge_len, DoCommandFlag flags = DC_NONE);
+CommandCost CheckBridgeAvailability(BridgeType bridge_type, uint bridge_len, DoCommandFlag flags = DC_NONE);
 int CalcBridgeLenCostFactor(int x);
 
 void ResetBridges();

src/bridge_gui.cpp

@@ -375,7 +375,7 @@ void ShowBuildBridgeWindow(TileIndex start, TileIndex end, TransportType transpo
 		case TRANSPORT_RAIL: last_bridge_type = _last_railbridge_type; break;
 		default: break; // water ways and air routes don't have bridge types
 	}
-	if (_ctrl_pressed && CheckBridgeAvailability(last_bridge_type, bridge_len)) {
+	if (_ctrl_pressed && CheckBridgeAvailability(last_bridge_type, bridge_len).Succeeded()) {
 		DoCommandP(end, start, type | last_bridge_type, CMD_BUILD_BRIDGE | CMD_MSG(STR_ERROR_CAN_T_BUILD_BRIDGE_HERE), CcBuildBridge);
 		return;
 	}
@@ -396,7 +396,7 @@ void ShowBuildBridgeWindow(TileIndex start, TileIndex end, TransportType transpo
 
 		/* loop for all bridgetypes */
 		for (BridgeType brd_type = 0; brd_type != MAX_BRIDGES; brd_type++) {
-			if (CheckBridgeAvailability(brd_type, bridge_len)) {
+			if (CheckBridgeAvailability(brd_type, bridge_len).Succeeded()) {
 				/* bridge is accepted, add to list */
 				BuildBridgeData *item = bl->Append();
 				item->index = brd_type;

src/lang/english.txt

@@ -3539,6 +3539,7 @@ STR_ERROR_BRIDGEHEADS_NOT_SAME_HEIGHT                           :{WHITE}Bridge h
 STR_ERROR_BRIDGE_TOO_LOW_FOR_TERRAIN                            :{WHITE}Bridge is too low for the terrain
 STR_ERROR_START_AND_END_MUST_BE_IN                              :{WHITE}Start and end must be in line
 STR_ERROR_ENDS_OF_BRIDGE_MUST_BOTH                              :{WHITE}... ends of bridge must both be on land
+STR_ERROR_BRIDGE_TOO_LONG                                       :{WHITE}... bridge too long
 
 # Tunnel related errors
 STR_ERROR_CAN_T_BUILD_TUNNEL_HERE                               :{WHITE}Can't build tunnel here...

src/tunnelbridge_cmd.cpp

@@ -166,23 +166,26 @@ static CommandCost CheckBridgeSlopeSouth(Axis axis, Slope *tileh, uint *z)
 /** Is a bridge of the specified type and length available?
  * @param bridge_type Wanted type of bridge.
  * @param bridge_len  Wanted length of the bridge.
- * @return The requested bridge is available.
+ * @return A succeeded (the requested bridge is available) or failed (it cannot be built) command.
  */
-bool CheckBridgeAvailability(BridgeType bridge_type, uint bridge_len, DoCommandFlag flags)
+CommandCost CheckBridgeAvailability(BridgeType bridge_type, uint bridge_len, DoCommandFlag flags)
 {
 	if (flags & DC_QUERY_COST) {
-		return bridge_len <= (_settings_game.construction.longbridges ? 100U : 16U);
+		if (bridge_len <= (_settings_game.construction.longbridges ? 100U : 16U)) return CommandCost();
+		return_cmd_error(STR_ERROR_BRIDGE_TOO_LONG);
 	}
 
-	if (bridge_type >= MAX_BRIDGES) return false;
+	if (bridge_type >= MAX_BRIDGES) return CMD_ERROR;
 
 	const BridgeSpec *b = GetBridgeSpec(bridge_type);
-	if (b->avail_year > _cur_year) return false;
+	if (b->avail_year > _cur_year) return CMD_ERROR;
 
 	uint max = b->max_length;
 	if (max >= 16 && _settings_game.construction.longbridges) max = 100;
 
-	return b->min_length <= bridge_len && bridge_len <= max;
+	if (b->min_length > bridge_len) return CMD_ERROR;
+	if (bridge_len <= max) return CommandCost();
+	return_cmd_error(STR_ERROR_BRIDGE_TOO_LONG);
 }
 
 /** Build a Bridge
@@ -248,9 +251,10 @@ CommandCost CmdBuildBridge(TileIndex end_tile, DoCommandFlag flags, uint32 p1, u
 	uint bridge_len = GetTunnelBridgeLength(tile_start, tile_end);
 	if (transport_type != TRANSPORT_WATER) {
 		/* set and test bridge length, availability */
-		if (!CheckBridgeAvailability(bridge_type, bridge_len, flags)) return CMD_ERROR;
+		CommandCost ret = CheckBridgeAvailability(bridge_type, bridge_len, flags);
+		if (ret.Failed()) return ret;
 	} else {
-		if (bridge_len > (_settings_game.construction.longbridges ? 100U : 16U)) return CMD_ERROR;
+		if (bridge_len > (_settings_game.construction.longbridges ? 100U : 16U)) return_cmd_error(STR_ERROR_BRIDGE_TOO_LONG);
 	}
 
 	/* retrieve landscape height and ensure it's on land */