[dconf/wip/reorg: 493/523] user source: use threadsafe init for shmdir

[Ryan Lortie <ryanl src gnome org>]

commit fb6ad83ace3aa4c7fb912b202754161ae8c1da65
Author: Ryan Lortie <desrt desrt ca>
Date:   Fri Jul 6 14:06:04 2012 -0400

    user source: use threadsafe init for shmdir
    
    Otherwise it's possible for multiple threads to initialise it at the
    same time.
    
    Each thread will come up with the same value anyway, but it's a string,
    so we will leak all but one of them.

 engine/dconf-engine-source-user.c |    4 ++--
 1 files changed, 2 insertions(+), 2 deletions(-)
---
diff --git a/engine/dconf-engine-source-user.c b/engine/dconf-engine-source-user.c
index dba655f..7c44b79 100644
--- a/engine/dconf-engine-source-user.c
+++ b/engine/dconf-engine-source-user.c
@@ -41,8 +41,8 @@ dconf_engine_source_user_open_shm (const gchar *name)
   void *memory;
   gint fd;
 
-  if (shmdir == NULL)
-    shmdir = g_build_filename (g_get_user_runtime_dir (), "dconf", NULL);
+  if (g_once_init_enter (&shmdir))
+    g_once_init_leave (&shmdir, g_build_filename (g_get_user_runtime_dir (), "dconf", NULL));
 
   filename = g_build_filename (shmdir, name, NULL);
   memory = NULL;