[glib] GSettingsBackend: fix NULL vs "" context issues

[Ryan Lortie <ryanl src gnome org>]

commit defd75fbc53511e27d178373ba6caa226c1ab3cf
Author: Ryan Lortie <desrt desrt ca>
Date:   Thu Apr 15 18:30:06 2010 -0400

    GSettingsBackend: fix NULL vs "" context issues

 gio/gsettingsbackend.c |    6 ++++--
 1 files changed, 4 insertions(+), 2 deletions(-)
---
diff --git a/gio/gsettingsbackend.c b/gio/gsettingsbackend.c
index 9828929..3b3de90 100644
--- a/gio/gsettingsbackend.c
+++ b/gio/gsettingsbackend.c
@@ -738,7 +738,7 @@ g_settings_backend_class_init (GSettingsBackendClass *class)
   g_object_class_install_property (gobject_class, PROP_CONTEXT,
     g_param_spec_string ("context", P_("Context"),
                          P_("An identifier to decide which storage to use"),
-                         NULL, G_PARAM_READWRITE |
+                         "", G_PARAM_READWRITE |
                          G_PARAM_CONSTRUCT_ONLY | G_PARAM_STATIC_STRINGS));
 
 }
@@ -791,7 +791,7 @@ get_default_backend (const gchar *context)
       extension = extensions->data;
     }
 
-  if (context)
+  if (context[0] != '\0') /* (context != "") */
     {
       GSettingsBackendClass *backend_class;
       GTypeClass *class;
@@ -876,6 +876,8 @@ g_settings_backend_supports_context (const gchar *context)
 {
   GSettingsBackend *backend;
 
+  g_return_val_if_fail (context != NULL, NULL);
+
   backend = get_default_backend (context);
 
   if (backend)