[nautilus] Don't allow drops on tabs for unwritable slots

[William Jon McCann <mccann src gnome org>]

commit 6aa7f6cbdc57cc1000b1be69f131e3223c2486a3
Author: William Jon McCann <jmccann redhat com>
Date:   Fri Aug 24 20:01:47 2012 -0400

    Don't allow drops on tabs for unwritable slots
    
    https://bugzilla.gnome.org/show_bug.cgi?id=329515

 src/nautilus-window-slot-dnd.c |   12 ++++++++++++
 1 files changed, 12 insertions(+), 0 deletions(-)
---
diff --git a/src/nautilus-window-slot-dnd.c b/src/nautilus-window-slot-dnd.c
index 4ec439f..7a1a098 100644
--- a/src/nautilus-window-slot-dnd.c
+++ b/src/nautilus-window-slot-dnd.c
@@ -97,6 +97,18 @@ slot_proxy_drag_motion (GtkWidget          *widget,
     }
   }
 
+  if (target_uri != NULL) {
+    NautilusFile *file;
+    gboolean can;
+    file = nautilus_file_get_existing_by_uri (target_uri);
+    can = nautilus_file_can_write (file);
+    g_object_unref (file);
+    if (!can) {
+      action = 0;
+      goto out;
+    }
+  }
+
   if (drag_info->have_data &&
       drag_info->have_valid_data) {
     if (drag_info->info == NAUTILUS_ICON_DND_GNOME_ICON_LIST) {