[seahorse] Only permit import from clipboard when data is available

[Stefan Walter <stefw src gnome org>]

commit e76c46a7f4bfca6df0851be01df49d5053e03218
Author: Michael I Doherty <michael i doherty intel com>
Date:   Fri Jul 5 15:37:17 2013 +0100

    Only permit import from clipboard when data is available
    
    https://bugzilla.gnome.org/show_bug.cgi?id=703394

 src/seahorse-key-manager.c |   22 +++++++++++++++++++++-
 1 files changed, 21 insertions(+), 1 deletions(-)
---
diff --git a/src/seahorse-key-manager.c b/src/seahorse-key-manager.c
index d7c0b99..907008b 100644
--- a/src/seahorse-key-manager.c
+++ b/src/seahorse-key-manager.c
@@ -364,12 +364,25 @@ on_target_drag_data_received (GtkWindow* window, GdkDragContext* context, gint x
        }
 }
 
+static void
+update_clipboard_state (GtkClipboard* clipboard, GdkEvent* event, GtkActionGroup* group)
+{
+       GtkAction *action;
+       gboolean text_available;
+
+       text_available = gtk_clipboard_wait_is_text_available (clipboard);
+       action = gtk_action_group_get_action (group, "edit-import-clipboard");
+       gtk_action_set_sensitive (action, text_available);
+}
+
 static void 
 on_clipboard_received (GtkClipboard* board, const char* text, SeahorseKeyManager* self) 
 {
        g_return_if_fail (SEAHORSE_IS_KEY_MANAGER (self));
        g_return_if_fail (GTK_IS_CLIPBOARD (board));
-       g_return_if_fail (text != NULL);
+
+       if (text == NULL)
+               return;
 
        g_assert(self->pv->filter_entry);
        if (gtk_widget_is_focus (GTK_WIDGET (self->pv->filter_entry)) == TRUE)
@@ -638,6 +651,7 @@ seahorse_key_manager_constructed (GObject *object)
        GtkAction *action;
        GtkWindow *window;
        GtkBuilder *builder;
+       GtkClipboard* clipboard;
 
        G_OBJECT_CLASS (seahorse_key_manager_parent_class)->constructed (object);
 
@@ -691,6 +705,12 @@ seahorse_key_manager_constructed (GObject *object)
        g_signal_connect_object (gtk_builder_get_object (builder, "new-button"),
                                 "clicked", G_CALLBACK (on_keymanager_new_button), self, 0);
 
+       /* Make sure import is only available with clipboard content */
+       action = gtk_action_group_get_action (actions, "edit-import-clipboard");
+       clipboard = gtk_clipboard_get(GDK_SELECTION_PRIMARY);
+       g_signal_connect (clipboard, "owner-change", G_CALLBACK (update_clipboard_state), actions);
+       update_clipboard_state (clipboard, NULL, actions);
+
        /* Flush all updates */
        seahorse_catalog_ensure_updated (SEAHORSE_CATALOG (self));