Make ID icons safe for deletion from threads

Added a lock-free deferred queue for deletion. Now if ID icon
is requested to be freed from non-main thread, it will be added
to the deferred list. Actual deletion will happen later from main
thread.

Currently actual deletion only happens next time BKE_icon_id_delete()
is called, which might not be enough. But it's easy to enforce
deferred deletion.

Icons for preview images are not covered by deferred deletion yet.

Reviewers: mont29

Differential Revision: https://developer.blender.org/D3146

1 files changed, 3 insertions, 0 deletions

diff --git a/source/blender/blenkernel/BKE_icons.h b/source/blender/blenkernel/BKE_icons.h
index a9ca5cc8bbb..c3f5d7bf7c2 100644
--- a/source/blender/blenkernel/BKE_icons.h
+++ b/source/blender/blenkernel/BKE_icons.h
@@ -75,6 +75,9 @@ void BKE_icon_changed(const int icon_id);
 /* free all icons */
 void BKE_icons_free(void);
 
+/* free all icons marked for deferred deletion */
+void BKE_icons_deferred_free(void);
+
 /* free the preview image for use in list */
 void BKE_previewimg_freefunc(void *link);