egl: Add _eglAddAtExitCall.

Add a convenient wrapper to register atexit calls.  Add mutex to
_eglGlobal along the way.

Signed-off-by: Chia-I Wu <olvaffe@gmail.com>

src/egl/main/eglglobals.c

@@ -1,13 +1,53 @@
 #include <stdlib.h>
+#include <assert.h>
 #include "eglglobals.h"
 #include "egldisplay.h"
 #include "egllog.h"
+#include "eglmutex.h"
 
+
+#define ARRAY_SIZE(a) (sizeof(a) / sizeof((a)[0]))
+
+
+static _EGL_DECLARE_MUTEX(_eglGlobalMutex);
 struct _egl_global _eglGlobal =
 {
+   &_eglGlobalMutex,       /* Mutex */
    1,                      /* FreeScreenHandle */
    0x0,                    /* ClientAPIsMask */
    { 0x0 },                /* ClientAPIs */
    0,                      /* NumDrivers */
    { NULL },               /* Drivers */
+   0,                      /* NumAtExitCalls */
+   { NULL },               /* AtExitCalls */
 };
+
+
+static void
+_eglAtExit(void)
+{
+   EGLint i;
+   for (i = _eglGlobal.NumAtExitCalls - 1; i >= 0; i--)
+      _eglGlobal.AtExitCalls[i]();
+}
+
+
+void
+_eglAddAtExitCall(void (*func)(void))
+{
+   if (func) {
+      static EGLBoolean registered = EGL_FALSE;
+
+      _eglLockMutex(_eglGlobal.Mutex);
+
+      if (!registered) {
+         atexit(_eglAtExit);
+         registered = EGL_TRUE;
+      }
+
+      assert(_eglGlobal.NumAtExitCalls < ARRAY_SIZE(_eglGlobal.AtExitCalls));
+      _eglGlobal.AtExitCalls[_eglGlobal.NumAtExitCalls++] = func;
+
+      _eglUnlockMutex(_eglGlobal.Mutex);
+   }
+}

src/egl/main/eglglobals.h

@@ -4,6 +4,7 @@
 #include "egltypedefs.h"
 #include "eglhash.h"
 #include "eglcurrent.h"
+#include "eglmutex.h"
 
 
 /**
@@ -11,6 +12,7 @@
  */
 struct _egl_global
 {
+   _EGLMutex *Mutex;
    EGLScreenMESA FreeScreenHandle;
 
    /* bitmaks of supported APIs (supported by _some_ driver) */
@@ -20,10 +22,17 @@ struct _egl_global
 
    EGLint NumDrivers;
    _EGLDriver *Drivers[10];
+
+   EGLint NumAtExitCalls;
+   void (*AtExitCalls[10])(void);
 };
 
 
 extern struct _egl_global _eglGlobal;
 
 
+extern void
+_eglAddAtExitCall(void (*func)(void));
+
+
 #endif /* EGLGLOBALS_INCLUDED */