gmain: use atomic operation instead of GMutex to access g_main_context_default()

I think it is wasteful to use a mutex every time the default main context
is accessed. Especially, as the default main context is used all the
time.
This commit is contained in:
Thomas Haller 2019-10-07 13:22:30 +00:00 committed by Philip Withnall
parent 038ec3de31
commit 39dd2be538

View File

@ -439,9 +439,6 @@ static void block_source (GSource *source);
static GMainContext *glib_worker_context;
G_LOCK_DEFINE_STATIC (main_loop);
static GMainContext *default_main_context;
#ifndef G_OS_WIN32
@ -667,34 +664,35 @@ g_main_context_new (void)
/**
* g_main_context_default:
*
*
* Returns the global default main context. This is the main context
* used for main loop functions when a main loop is not explicitly
* specified, and corresponds to the "main" main loop. See also
* g_main_context_get_thread_default().
*
*
* Returns: (transfer none): the global default main context.
**/
GMainContext *
g_main_context_default (void)
{
/* Slow, but safe */
G_LOCK (main_loop);
static GMainContext *default_main_context;
if (!default_main_context)
if (g_once_init_enter (&default_main_context))
{
default_main_context = g_main_context_new ();
GMainContext *context;
TRACE (GLIB_MAIN_CONTEXT_DEFAULT (default_main_context));
context = g_main_context_new ();
TRACE (GLIB_MAIN_CONTEXT_DEFAULT (context));
#ifdef G_MAIN_POLL_DEBUG
if (_g_main_poll_debug)
g_print ("default context=%p\n", default_main_context);
g_print ("default context=%p\n", context);
#endif
}
G_UNLOCK (main_loop);
g_once_init_leave ((gsize *) &default_main_context, (gsize) context);
}
return default_main_context;
}