Fix argb_layer handling in xine-libs OSD stack.

xine-libs OSD stack is event driven and some memory blocks are not copied
but responsibility to free the memory moves to different layers of the
OSD stack.
When argb_layer was introduced, this behavior was not taken into account
and as such it is likely that for example osd_free_object() frees the
argb_layer while vdpau_overlay_* functions still access the memory.
Passing responsibility for the argb_layer is not that easy as it seems as
the design goal of the argb_layer was to not duplicate any memory of the
argb_buffer which all other OSD functions usually do.
To solve this issue, argb_layer_t will be turned into a managed data
structure by introducing a ref_count member. ref_count increases as more
layers of the OSD stack hold a reference to that memory block, and it
decreases when they are no longer interested in it. When ref_count reaches
zero the memory block is freed automatically. To deal with ref counting,
set_argb_layer_ptr() has been introduced.
Some functions of the OSD layers had to be modified to deal with reference
tracking. For convinience, osd_free_object() should clear the argb_buffer
pointer so that the buffer may be freed safely after returning.

2 files changed, 3 insertions, 1 deletions

diff --git a/include/xine/osd.h b/include/xine/osd.h
index 00df97ad2..44471534b 100644
--- a/include/xine/osd.h
+++ b/include/xine/osd.h
@@ -69,7 +69,7 @@ struct osd_object_s {
   /* this holds an optional ARGB overlay, which
    * is only be used by supported video_out modules.
    * right now this is only vdpau */
-  argb_layer_t argb_layer;
+  argb_layer_t *argb_layer;
 
   int32_t handle;
 };
diff --git a/include/xine/video_out.h b/include/xine/video_out.h
index 9d5380884..799e8f726 100644
--- a/include/xine/video_out.h
+++ b/include/xine/video_out.h
@@ -449,6 +449,7 @@ typedef struct argb_layer_s {
   /* dirty area */
   int x1, y1;
   int x2, y2;
+  int ref_count;
 } argb_layer_t;
 
 struct vo_overlay_s {
@@ -489,6 +490,7 @@ struct vo_overlay_s {
   argb_layer_t     *argb_layer;
 };
 
+void set_argb_layer_ptr(argb_layer_t **dst, argb_layer_t *src);
 
 /* API to video_overlay manager
  *