[evolution-data-server] store_get_inbox_folder_sync: Add a NULL check.

[Matthew Barnes <mbarnes src gnome org>]

commit d559cb488a1a0120c398840ce5c04f113148334a
Author: Matthew Barnes <mbarnes redhat com>
Date:   Wed Jan 25 10:43:40 2012 -0500

    store_get_inbox_folder_sync: Add a NULL check.
    
    Verify the get_folder_sync() method is implemented before invoking it.

 camel/camel-store.c |    4 +++-
 1 files changed, 3 insertions(+), 1 deletions(-)
---
diff --git a/camel/camel-store.c b/camel/camel-store.c
index c2529c3..be38c1c 100644
--- a/camel/camel-store.c
+++ b/camel/camel-store.c
@@ -302,8 +302,10 @@ store_get_inbox_folder_sync (CamelStore *store,
 	CamelStoreClass *class;
 	CamelFolder *folder;
 
-	/* Assume the inbox's name is "inbox" and open with default flags. */
 	class = CAMEL_STORE_GET_CLASS (store);
+	g_return_val_if_fail (class->get_folder_sync != NULL, NULL);
+
+	/* Assume the inbox's name is "inbox" and open with default flags. */
 	folder = class->get_folder_sync (store, "inbox", 0, cancellable, error);
 	CAMEL_CHECK_GERROR (store, get_folder_sync, folder != NULL, error);