[evolution-ews/evolution-ews-3-12] Bug #684425 - Do not pass NULL text to gtk_entry_set_text()

[Milan Crha <mcrha src gnome org>]

commit 88e9c9601565fe05dedab269b8905e5ed8b7b1fa
Author: Milan Crha <mcrha redhat com>
Date:   Fri Apr 11 11:01:04 2014 +0200

    Bug #684425 - Do not pass NULL text to gtk_entry_set_text()

 src/configuration/e-mail-config-ews-backend.c |   62 +++++++++++++++++++++++--
 1 files changed, 58 insertions(+), 4 deletions(-)
---
diff --git a/src/configuration/e-mail-config-ews-backend.c b/src/configuration/e-mail-config-ews-backend.c
index 74c35a7..d75c840 100644
--- a/src/configuration/e-mail-config-ews-backend.c
+++ b/src/configuration/e-mail-config-ews-backend.c
@@ -54,6 +54,60 @@ G_DEFINE_DYNAMIC_TYPE (
        e_mail_config_ews_backend,
        E_TYPE_MAIL_CONFIG_SERVICE_BACKEND)
 
+static gboolean
+e_ews_binding_transform_text_non_null (GBinding *binding,
+                                      const GValue *source_value,
+                                      GValue *target_value,
+                                      gpointer user_data)
+{
+       const gchar *str;
+
+       g_return_val_if_fail (G_IS_BINDING (binding), FALSE);
+       g_return_val_if_fail (source_value != NULL, FALSE);
+       g_return_val_if_fail (target_value != NULL, FALSE);
+
+       str = g_value_get_string (source_value);
+       if (!str)
+               str = "";
+
+       g_value_set_string (target_value, str);
+
+       return TRUE;
+}
+
+static GBinding *
+e_ews_binding_bind_object_text_property (gpointer source,
+                                        const gchar *source_property,
+                                        gpointer target,
+                                        const gchar *target_property,
+                                        GBindingFlags flags)
+{
+       GObjectClass *klass;
+       GParamSpec *property;
+
+       g_return_val_if_fail (G_IS_OBJECT (source), NULL);
+       g_return_val_if_fail (source_property != NULL, NULL);
+       g_return_val_if_fail (G_IS_OBJECT (target), NULL);
+       g_return_val_if_fail (target_property != NULL, NULL);
+
+       klass = G_OBJECT_GET_CLASS (source);
+       property = g_object_class_find_property (klass, source_property);
+       g_return_val_if_fail (property != NULL, NULL);
+       g_return_val_if_fail (property->value_type == G_TYPE_STRING, NULL);
+
+       klass = G_OBJECT_GET_CLASS (target);
+       property = g_object_class_find_property (klass, target_property);
+       g_return_val_if_fail (property != NULL, NULL);
+       g_return_val_if_fail (property->value_type == G_TYPE_STRING, NULL);
+
+       return g_object_bind_property_full (source, source_property,
+                                           target, target_property,
+                                           flags,
+                                           e_ews_binding_transform_text_non_null,
+                                           e_ews_binding_transform_text_non_null,
+                                           NULL, NULL);
+}
+
 static ESource *
 mail_config_ews_backend_new_collection (EMailConfigServiceBackend *backend)
 {
@@ -226,7 +280,7 @@ mail_config_ews_backend_insert_widgets (EMailConfigServiceBackend *backend,
        gtk_widget_show (widget);
        priv->impersonate_user_entry = widget;  /* do not reference */
 
-       g_object_bind_property (
+       e_ews_binding_bind_object_text_property (
                settings, "impersonate-user",
                widget, "text",
                G_BINDING_BIDIRECTIONAL | G_BINDING_SYNC_CREATE);
@@ -263,19 +317,19 @@ mail_config_ews_backend_insert_widgets (EMailConfigServiceBackend *backend,
        priv->auth_check = widget;  /* do not reference */
        gtk_widget_show (widget);
 
-       g_object_bind_property (
+       e_ews_binding_bind_object_text_property (
                settings, "user",
                priv->user_entry, "text",
                G_BINDING_BIDIRECTIONAL |
                G_BINDING_SYNC_CREATE);
 
-       g_object_bind_property (
+       e_ews_binding_bind_object_text_property (
                settings, "hosturl",
                priv->host_entry, "text",
                G_BINDING_BIDIRECTIONAL |
                G_BINDING_SYNC_CREATE);
 
-       g_object_bind_property (
+       e_ews_binding_bind_object_text_property (
                settings, "oaburl",
                priv->oab_entry, "text",
                G_BINDING_BIDIRECTIONAL |