gst/gstelementfactory.c (gst_element_factory_create): Avoid eating the caller's refcount.

Original commit message from CVS:
2005-09-20  Andy Wingo  <wingo@pobox.com>

* gst/gstelementfactory.c (gst_element_factory_create): Avoid
eating the caller's refcount.

* gst/gstobject.h (GST_OBJECT_REFCOUNT)
(GST_OBJECT_REFCOUNT_VALUE): Conditionally fondle the right
refcount.

* gst/gstconfig.h.in (GST_HAVE_GLIB_2_8):
* configure.ac (GST_HAVE_GLIB_2_8_DEFINE): Make the availability
of GLib 2.8 public, so we can know which refcount to check in
tests.

* gst/gstobject.c: Use the GST_HAVE_GLIB_2_8 define.
(gst_object_init): Only set the gst refcount if we're going ahead
with the refcount hack.

4 files changed, 28 insertions, 6 deletions

diff --git a/gst/gstconfig.h.in b/gst/gstconfig.h.in
index 0647d5407..70b60ebf4 100644
--- a/gst/gstconfig.h.in
+++ b/gst/gstconfig.h.in
@@ -112,6 +112,10 @@
 /* whether or not the CPU supports unaligned access */
 @GST_HAVE_UNALIGNED_ACCESS_DEFINE@
 
+/* whether or not we are using glib 2.8 api, e.g. atomic gobject
+   refcounting */
+@GST_HAVE_GLIB_2_8_DEFINE@
+
 /***** Deal with XML stuff, we have to handle both loadsave and registry *****/
 
 #if (! (defined(GST_DISABLE_LOADSAVE) && defined(GST_DISABLE_REGISTRY)) )
diff --git a/gst/gstelementfactory.c b/gst/gstelementfactory.c
index 5afb15cdb..c545b62f5 100644
--- a/gst/gstelementfactory.c
+++ b/gst/gstelementfactory.c
@@ -349,15 +349,27 @@ gst_element_factory_create (GstElementFactory * factory, const gchar * name)
 {
   GstElement *element;
   GstElementClass *oclass;
+  GstElementFactory *newfactory;
 
   g_return_val_if_fail (factory != NULL, NULL);
 
-  factory =
+  gst_object_ref (factory);
+
+  newfactory =
       GST_ELEMENT_FACTORY (gst_plugin_feature_load (GST_PLUGIN_FEATURE
           (factory)));
-  if (factory == NULL) {
-    GST_DEBUG ("warning: loading the plugin for this factory returned NULL");
+  if (newfactory == NULL) {
+    /* it could be factory is invalid. with ref-eating functions nothing is
+       certain! */
+    GST_WARNING ("loading the plugin for factory %p returned NULL", factory);
     return NULL;
+  } else if (newfactory != factory) {
+    /* gst_plugin_feature_load ate the ref we added to the factory */
+    factory = newfactory;
+  } else {
+    /* strip off our extra ref */
+    gst_object_unref (factory);
+    factory = newfactory;
   }
 
   if (name)
@@ -392,7 +404,6 @@ gst_element_factory_create (GstElementFactory * factory, const gchar * name)
     gst_object_set_name (GST_OBJECT (element), name);
 
   GST_DEBUG ("created \"%s\"", GST_PLUGIN_FEATURE_NAME (factory));
-  gst_object_unref (factory);
 
   return element;
 }
diff --git a/gst/gstobject.c b/gst/gstobject.c
index 91bd7aa95..79cc89945 100644
--- a/gst/gstobject.c
+++ b/gst/gstobject.c
@@ -33,7 +33,7 @@
 #endif
 
 #define DEBUG_REFCOUNT
-#ifndef HAVE_GLIB_2_8
+#ifndef GST_HAVE_GLIB_2_8
 #define REFCOUNT_HACK
 #endif
 
@@ -218,7 +218,9 @@ gst_object_init (GTypeInstance * instance, gpointer g_class)
   object->parent = NULL;
   object->name = NULL;
   GST_CAT_LOG_OBJECT (GST_CAT_REFCOUNTING, object, "%p new", object);
+#ifdef REFCOUNT_HACK
   gst_atomic_int_set (&object->refcount, 1);
+#endif
   PATCH_REFCOUNT (object);
 
   object->flags = 0;
diff --git a/gst/gstobject.h b/gst/gstobject.h
index 3f6cb6727..31e2645d3 100644
--- a/gst/gstobject.h
+++ b/gst/gstobject.h
@@ -55,8 +55,13 @@ typedef enum
   GST_OBJECT_FLAG_LAST   = 4
 } GstObjectFlags;
 
+#ifdef GST_HAVE_GLIB_2_8
+#define GST_OBJECT_REFCOUNT(obj)                (((GObject*)(obj))->ref_count)
+#define GST_OBJECT_REFCOUNT_VALUE(obj)          (g_atomic_int_get (&((GObject*)(obj))->ref_count))
+#else
 #define GST_OBJECT_REFCOUNT(obj)                ((GST_OBJECT_CAST(obj))->refcount)
 #define GST_OBJECT_REFCOUNT_VALUE(obj)          (g_atomic_int_get (&(GST_OBJECT_CAST(obj))->refcount))
+#endif /* GST_HAVE_GLIB_2_8 */
 
 /* we do a GST_OBJECT_CAST to avoid type checking, better call these
  * function with a valid object! */
@@ -84,7 +89,7 @@ struct _GstObject {
   GObject 	 object;
 
   /*< public >*/
-  gint           refcount;
+  gint           refcount;    /* only used ifndef GST_HAVE_GLIB_0_8 */
 
   /*< public >*/ /* with LOCK */
   GMutex        *lock;        /* object LOCK */