* Fixed bug. If a transport add-on returned an empty

port list, the transport add-on could be selected,
  altough later using it would fail. In that case
  now a sub menu item is created containing the text
  "No printer found!" and selecting it won't work.
  TODO the contents of the sub menu should be refreshed
  before the sub menu is opened, so that only currently
  connected and turned on printers are shown.


git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@39258 a95241bf-73f2-0310-859d-f6bbb57e9c96

src/preferences/print/AddPrinterDialog.cpp

@@ -364,25 +364,37 @@ AddPrinterDialog::_FillTransportMenu(BMenu* menu)
 
 		// Now get ports...
 		BString portId, portName;
+		int32 error;
 		msg.MakeEmpty();
 		msg.what = B_GET_PROPERTY;
 		msg.AddSpecifier("Ports");
 		if (transport.SendMessage(&msg, &reply) != B_OK ||
-			reply.FindString("port_id", &portId) != B_OK) {
-			// Can't find ports; so just show transport item, no menu
+			reply.FindInt32("error", &error) != B_OK ||
+			error != B_OK) {
+			// Transport does not provide list of ports
 			BMessage* menuMsg = new BMessage(kTransportSelectedMsg);
 			menuMsg->AddString("name", transportName);
 			menu->AddItem(new BMenuItem(transportName.String(), menuMsg));
 			continue;
 		}
 
-		// We have at least one port; so create submenu
+		// Create submenu
 		BMenu* transportMenu = new BMenu(transportName.String());
 		menu->AddItem(transportMenu);
 		transportMenu->SetRadioMode(true);
 		menu->ItemAt(menu->IndexOf(transportMenu))->
 			SetMessage(new BMessage(kTransportSelectedMsg));
 
+
+		if (reply.FindString("port_id", &portId) != B_OK) {
+			// Show error message in submenu
+			BMessage* portMsg = new BMessage(kTransportSelectedMsg);
+			transportMenu->AddItem(new BMenuItem(
+				B_TRANSLATE("No printer found!"), portMsg));
+			continue;
+		}
+
+		// Add ports to submenu
 		for (int32 i = 0; reply.FindString("port_id", i, &portId) == B_OK;
 			i++) {
 			if (reply.FindString("port_name", i, &portName) != B_OK