[vlc-devel] [vlc-commits] Revert "lib: media: Use an atomic refcounter"

[Hugo Beauzée-Luyssen]

On Mon, Oct 28, 2019, at 11:34 AM, Hugo Beauzée-Luyssen wrote:
> vlc | branch: master | Hugo Beauzée-Luyssen <hugo at beauzee.fr> | Thu Oct 
> 24 10:28:35 2019 +0200| [cf14bc8f63bc19092f19354d93f99c289d00afb4] | 
> committer: Hugo Beauzée-Luyssen
> 
> Revert "lib: media: Use an atomic refcounter"
> 
> This reverts commit 1b07eaa8612eb77a28178a8739a1a23d4dc16cef.
> 
> > http://git.videolan.org/gitweb.cgi/vlc.git/?a=commit;h=cf14bc8f63bc19092f19354d93f99c289d00afb4
> ---
> 
>  lib/media.c          | 8 +++++---
>  lib/media_internal.h | 3 +--
>  2 files changed, 6 insertions(+), 5 deletions(-)
> 
> diff --git a/lib/media.c b/lib/media.c
> index 36dee3b9e5..d4e3ba7a62 100644
> --- a/lib/media.c
> +++ b/lib/media.c
> @@ -394,7 +394,7 @@ libvlc_media_t * libvlc_media_new_from_input_item(
>  
>      p_md->p_libvlc_instance = p_instance;
>      p_md->p_input_item      = p_input_item;
> -    vlc_atomic_rc_init(&p_md->refcount);
> +    p_md->i_refcount        = 1;
>  
>      vlc_cond_init(&p_md->parsed_cond);
>      vlc_mutex_init(&p_md->parsed_lock);
> @@ -547,7 +547,9 @@ void libvlc_media_release( libvlc_media_t *p_md )
>      if (!p_md)
>          return;
>  
> -    if(!vlc_atomic_rc_dec( &p_md->refcount ))
> +    p_md->i_refcount--;
> +
> +    if( p_md->i_refcount > 0 )
>          return;
>  
>      uninstall_input_item_observer( p_md );
> @@ -583,7 +585,7 @@ void libvlc_media_release( libvlc_media_t *p_md )
>  void libvlc_media_retain( libvlc_media_t *p_md )
>  {
>      assert (p_md);
> -    vlc_atomic_rc_inc(&p_md->refcount);
> +    p_md->i_refcount++;
>  }
>  
>  /**************************************************************************
> diff --git a/lib/media_internal.h b/lib/media_internal.h
> index cfeb056178..aefc731c68 100644
> --- a/lib/media_internal.h
> +++ b/lib/media_internal.h
> @@ -29,13 +29,12 @@
>  
>  #include <vlc_common.h>
>  #include <vlc_input.h>
> -#include <vlc_atomic.h>
>  
>  struct libvlc_media_t
>  {
>      libvlc_event_manager_t event_manager;
>      input_item_t      *p_input_item;
> -    vlc_atomic_rc_t   refcount;
> +    int                i_refcount;
>      libvlc_instance_t *p_libvlc_instance;
>      libvlc_state_t     state;
>      VLC_FORWARD_DECLARE_OBJECT(libvlc_media_list_t*) p_subitems; /* A 
> media descriptor can have Sub items. This is the only dependancy we 
> really have on media_list */
> 

I can't find back the rational for reverting this commit, but with a708c988091d6bc770212f5deeaba45e2395f4b2 it seems to be required, since the refcount will be accessed from the preparser thread & the libvlc_media_parse_with_options thread, as can be seen here: https://code.videolan.org/videolan/medialibrary/-/jobs/487725

Any objection in re-introducing this commit?

-- 
  Hugo Beauzée-Luyssen
  hugo at beauzee.fr