gluploadelement: Avoid race condition of base class' context.

The base class' context may change, we should use the common API
with lock to access it, rather than the just directly access the
struct field.

Part-of: <https://gitlab.freedesktop.org/gstreamer/gst-plugins-base/-/merge_requests/916>

diff --git a/ext/gl/gstgluploadelement.c b/ext/gl/gstgluploadelement.c
index fab026b..7de7bba 100644 (file)
--- a/ext/gl/gstgluploadelement.c
+++ b/ext/gl/gstgluploadelement.c
@@ -167,7 +167,7 @@ _gst_gl_upload_element_transform_caps (GstBaseTransform * bt,
   if (base_filter->display && !gst_gl_base_filter_find_gl_context (base_filter))
     return NULL;
 
-  context = GST_GL_BASE_FILTER (bt)->context;
+  context = gst_gl_base_filter_get_gl_context (base_filter);
 
   GST_OBJECT_LOCK (upload);
   if (upload->upload == NULL) {
@@ -191,7 +191,10 @@ _gst_gl_upload_element_transform_caps (GstBaseTransform * bt,
 
   ret_caps =
       gst_gl_upload_transform_caps (ul, context, direction, caps, filter);
+
   gst_object_unref (ul);
+  if (context)
+    gst_object_unref (context);
 
   return ret_caps;
 }