[nautilus] file-undo-manager: fix trash undo invalidation

[Carlos Soriano Sánchez <csoriano src gnome org>]

commit 11fdde78eb2957fe297b9e2a77c521d64649a6f5
Author: Razvan Chitu <razvan ch95 gmail com>
Date:   Sat Mar 5 13:32:40 2016 +0200

    file-undo-manager: fix trash undo invalidation
    
    In Nautilus, when the Trash is emptied, trash undo / redo operations are
    invalidated by the undo manager. However, only the undo operations should be
    invalidated, because a redo is not affected by the state of the Trash. In order
    to fix this, change the invalidation condition to only target undo.
    
    https://bugzilla.gnome.org/show_bug.cgi?id=763134

 libnautilus-private/nautilus-file-undo-manager.c |   13 ++++---------
 1 files changed, 4 insertions(+), 9 deletions(-)
---
diff --git a/libnautilus-private/nautilus-file-undo-manager.c 
b/libnautilus-private/nautilus-file-undo-manager.c
index 862060f..0fb1583 100644
--- a/libnautilus-private/nautilus-file-undo-manager.c
+++ b/libnautilus-private/nautilus-file-undo-manager.c
@@ -83,15 +83,10 @@ trash_state_changed_cb (NautilusTrashMonitor *monitor,
 {
        NautilusFileUndoManager *self = user_data;
 
-       if (!is_empty) {
-               return;
-       }
-
-       if (self->priv->state == NAUTILUS_FILE_UNDO_MANAGER_STATE_NONE) {
-               return;
-       }
-
-       if (NAUTILUS_IS_FILE_UNDO_INFO_TRASH (self->priv->info)) {
+       /* A trash operation cannot be undone if the trash is empty */
+       if (is_empty &&
+           self->priv->state == NAUTILUS_FILE_UNDO_MANAGER_STATE_UNDO &&
+           NAUTILUS_IS_FILE_UNDO_INFO_TRASH (self->priv->info)) {
                file_undo_manager_clear (self);
                g_signal_emit (self, signals[SIGNAL_UNDO_CHANGED], 0);
        }