printing: Make sure destroy function is always called by gtk_enumerate_printers

When GtkPrinterFunc always returns FALSE, for example when looking for
a non existent printer, if print list is done for all backends or print
backend status is UNAVAILABLE, gtk_enumerate_printers() finishes with an
empty backend list and destroy function is never called. We need to
check the backend list again after calling list_printers_init for all
backends and finish the enumeration if it's empty.

https://bugzilla.gnome.org/show_bug.cgi?id=672125

diff --git a/gtk/gtkprinter.c b/gtk/gtkprinter.c
index 05e67e9a0ab2543f10b6d1c02720516d25c32c39..ada20b5d2f14d701e25b2cfbaff9e21018fd97cd 100644 (file)
--- a/gtk/gtkprinter.c
+++ b/gtk/gtkprinter.c
@@ -1151,15 +1151,10 @@ backend_status_changed (GObject    *object,
 }
 
 static void
-list_done_cb (GtkPrintBackend *backend, 
-             PrinterList     *printer_list)
+list_printers_remove_backend (PrinterList     *printer_list,
+                              GtkPrintBackend *backend)
 {
   printer_list->backends = g_list_remove (printer_list->backends, backend);
-  
-  g_signal_handlers_disconnect_by_func (backend, list_added_cb, printer_list);
-  g_signal_handlers_disconnect_by_func (backend, list_done_cb, printer_list);
-  g_signal_handlers_disconnect_by_func (backend, backend_status_changed, printer_list);
-  
   gtk_print_backend_destroy (backend);
   g_object_unref (backend);
 
@@ -1167,6 +1162,17 @@ list_done_cb (GtkPrintBackend *backend,
     free_printer_list (printer_list);
 }
 
+static void
+list_done_cb (GtkPrintBackend *backend,
+             PrinterList     *printer_list)
+{
+  g_signal_handlers_disconnect_by_func (backend, list_added_cb, printer_list);
+  g_signal_handlers_disconnect_by_func (backend, list_done_cb, printer_list);
+  g_signal_handlers_disconnect_by_func (backend, backend_status_changed, printer_list);
+
+  list_printers_remove_backend(printer_list, backend);
+}
+
 static gboolean
 list_printers_init (PrinterList     *printer_list,
                    GtkPrintBackend *backend)
@@ -1191,11 +1197,7 @@ list_printers_init (PrinterList     *printer_list,
   
   if (status == GTK_PRINT_BACKEND_STATUS_UNAVAILABLE || 
       gtk_print_backend_printer_list_is_done (backend))
-    {
-      printer_list->backends = g_list_remove (printer_list->backends, backend);
-      gtk_print_backend_destroy (backend);
-      g_object_unref (backend);
-    }
+    list_printers_remove_backend(printer_list, backend);
   else
     {
       g_signal_connect (backend, "printer-added",