Chip Davis : winemac.drv: Use InitOnceExecuteOnce to initialize OpenGL.

[Alexandre Julliard]

Module: wine
Branch: master
Commit: a55320f00b7d2b69e709d45fdf6c2afde84d1b23
URL:    https://source.winehq.org/git/wine.git/?a=commit;h=a55320f00b7d2b69e709d45fdf6c2afde84d1b23

Author: Chip Davis <cdavis at codeweavers.com>
Date:   Sun May 17 17:44:15 2020 -0500

winemac.drv: Use InitOnceExecuteOnce to initialize OpenGL.

Currently, there is a race condition where if two threads call into
OpenGL at the same time, one of them will initialize OpenGL, but the
other will barrel on ahead, thinking GL is already initialized, even
though the first thread hasn't finished initializing it yet. One of the
symptoms of this is that no pixel formats appear to be available,
because the first thread hasn't yet enumerated the available pixel
formats.

Signed-off-by: Chip Davis <cdavis at codeweavers.com>
Signed-off-by: Ken Thomases <ken at codeweavers.com>
Signed-off-by: Alexandre Julliard <julliard at winehq.org>

---

 dlls/winemac.drv/opengl.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/dlls/winemac.drv/opengl.c b/dlls/winemac.drv/opengl.c
index b80c8fffb0..b66af0f1c4 100644
--- a/dlls/winemac.drv/opengl.c
+++ b/dlls/winemac.drv/opengl.c
@@ -4242,7 +4242,7 @@ static void load_extensions(void)
 }
 
 
-static BOOL init_opengl(void)
+static BOOL CALLBACK init_opengl(INIT_ONCE *init_once, void *context, void **param)
 {
     static BOOL init_done = FALSE;
     unsigned int i;
@@ -4654,13 +4654,15 @@ static struct opengl_funcs opengl_funcs =
  */
 struct opengl_funcs * CDECL macdrv_wine_get_wgl_driver(PHYSDEV dev, UINT version)
 {
+    static INIT_ONCE opengl_init = INIT_ONCE_STATIC_INIT;
+
     if (version != WINE_WGL_DRIVER_VERSION)
     {
         ERR("version mismatch, opengl32 wants %u but macdrv has %u\n", version, WINE_WGL_DRIVER_VERSION);
         return NULL;
     }
 
-    if (!init_opengl()) return (void *)-1;
+    if (!InitOnceExecuteOnce(&opengl_init, init_opengl, NULL, NULL)) return (void *)-1;
 
     return &opengl_funcs;
 }