[glib] GStaticMutex: ABI fixup

[Ryan Lortie <ryanl src gnome org>]

commit 3e5a30fc17ee071254d7c2a70e1713d554e4a1ad
Author: Ryan Lortie <desrt desrt ca>
Date:   Mon Oct 10 13:13:31 2011 -0400

    GStaticMutex: ABI fixup
    
    Everything was OK as long as GMutex was backed by pthread_mutex_t on
    POSIX.  Since this is no longer the case, the ABI of GStaticMutex was
    broken.
    
    Fix that up by using pthread_mutex_t directly in the structure.  Since
    that's potentially incompatible with our GMutex implementation, set
    g_thread_use_default_impl to FALSE to cause the fallback code (which
    manually allocates a GMutex) to run, even in the case of
    already-existing code (without the need for a recompile).  This will
    cause the pthread_mutex_t part of the struct to be completely ignored.

 glib/deprecated/gthread-deprecated.c |   13 ++++++++-----
 glib/deprecated/gthread.h            |   25 +++++++++++++------------
 2 files changed, 21 insertions(+), 17 deletions(-)
---
diff --git a/glib/deprecated/gthread-deprecated.c b/glib/deprecated/gthread-deprecated.c
index 17ff343..861a599 100644
--- a/glib/deprecated/gthread-deprecated.c
+++ b/glib/deprecated/gthread-deprecated.c
@@ -113,7 +113,10 @@
 
 /* {{{1 Exported Variables */
 
-gboolean g_thread_use_default_impl = TRUE;
+/* Set this FALSE to have previously-compiled GStaticMutex code use the
+ * slow path (ie: call into us) to avoid compatibility problems.
+ */
+gboolean g_thread_use_default_impl = FALSE;
 
 GThreadFunctions g_thread_functions_for_glib_use =
 {
@@ -492,24 +495,24 @@ g_static_mutex_init (GStaticMutex *mutex)
  * Deprecated: 2.32: Just use a #GMutex
  */
 GMutex *
-g_static_mutex_get_mutex_impl (GMutex** mutex)
+g_static_mutex_get_mutex_impl (GStaticMutex* mutex)
 {
   GMutex *result;
 
   if (!g_thread_supported ())
     return NULL;
 
-  result = g_atomic_pointer_get (mutex);
+  result = g_atomic_pointer_get (&mutex->mutex);
 
   if (!result)
     {
       g_mutex_lock (&g_once_mutex);
 
-      result = *mutex;
+      result = mutex->mutex;
       if (!result)
         {
           result = g_mutex_new ();
-          g_atomic_pointer_set (mutex, result);
+          g_atomic_pointer_set (&mutex->mutex, result);
         }
 
       g_mutex_unlock (&g_once_mutex);
diff --git a/glib/deprecated/gthread.h b/glib/deprecated/gthread.h
index 97acda1..d15dd9d 100644
--- a/glib/deprecated/gthread.h
+++ b/glib/deprecated/gthread.h
@@ -114,18 +114,20 @@ void g_thread_set_priority     (GThread         *thread,
 void     g_thread_foreach      (GFunc         thread_func,
                                 gpointer      user_data) G_GNUC_DEPRECATED;
 
-#ifdef G_OS_WIN32
-typedef GMutex * GStaticMutex;
-#define G_STATIC_MUTEX_INIT NULL
+#ifndef G_OS_WIN32
+#include <pthread.h>
+#endif
+
 #define g_static_mutex_get_mutex g_static_mutex_get_mutex_impl
-#else /* G_OS_WIN32 */
-typedef struct {
-  GMutex *unused;
-  GMutex mutex;
+#define G_STATIC_MUTEX_INIT { NULL }
+typedef struct
+{
+  GMutex *mutex;
+#ifndef G_OS_WIN32
+  /* only for ABI compatibility reasons */
+  pthread_mutex_t unused;
+#endif
 } GStaticMutex;
-#define G_STATIC_MUTEX_INIT { NULL, { NULL } }
-#define g_static_mutex_get_mutex(s) (&(s)->mutex)
-#endif /* G_OS_WIN32 */
 
 #define g_static_mutex_lock(mutex) \
     g_mutex_lock (g_static_mutex_get_mutex (mutex))
@@ -135,6 +137,7 @@ typedef struct {
     g_mutex_unlock (g_static_mutex_get_mutex (mutex))
 void g_static_mutex_init (GStaticMutex *mutex) G_GNUC_DEPRECATED_FOR(g_mutex_init);
 void g_static_mutex_free (GStaticMutex *mutex) G_GNUC_DEPRECATED_FOR(g_mutex_free);
+GMutex* g_static_mutex_get_mutex_impl   (GStaticMutex *mutex);
 
 typedef struct _GStaticRecMutex GStaticRecMutex;
 struct _GStaticRecMutex
@@ -210,8 +213,6 @@ GLIB_VAR gboolean g_threads_got_initialized;
 #define g_thread_supported()    (g_threads_got_initialized)
 #endif
 
-GMutex* g_static_mutex_get_mutex_impl   (GMutex **mutex);
-
 GMutex *                g_mutex_new                                     (void) G_GNUC_DEPRECATED;
 void                    g_mutex_free                                    (GMutex         *mutex) G_GNUC_DEPRECATED;
 GCond *                 g_cond_new                                      (void) G_GNUC_DEPRECATED;