[FFmpeg-devel] [PATCH] [Trac ticket #3194] libavcodec/utils: Statically initialize global mutexes to avoid a leak.

[wm4]

On Sun, 15 Dec 2013 12:59:58 +0100
Hendrik Leppkes <h.leppkes at gmail.com> wrote:

> On Sun, Dec 15, 2013 at 12:17 PM, Tomer Barletz <barletz at gmail.com> wrote:
> > ---
> >  libavcodec/utils.c | 25 +++++++------------------
> >  1 file changed, 7 insertions(+), 18 deletions(-)
> >
> > diff --git a/libavcodec/utils.c b/libavcodec/utils.c
> > index 73370fe..0653acc 100644
> > --- a/libavcodec/utils.c
> > +++ b/libavcodec/utils.c
> > @@ -74,20 +74,6 @@ static int default_lockmgr_cb(void **arg, enum AVLockOp op)
> >      case AV_LOCK_CREATE:
> >          return 0;
> >      case AV_LOCK_OBTAIN:
> > -        if (!*mutex) {
> > -            pthread_mutex_t *tmp = av_malloc(sizeof(pthread_mutex_t));
> > -            if (!tmp)
> > -                return AVERROR(ENOMEM);
> > -            if ((err = pthread_mutex_init(tmp, NULL))) {
> > -                av_free(tmp);
> > -                return AVERROR(err);
> > -            }
> > -            if (avpriv_atomic_ptr_cas(mutex, NULL, tmp)) {
> > -                pthread_mutex_destroy(tmp);
> > -                av_free(tmp);
> > -            }
> > -        }
> > -
> >          if ((err = pthread_mutex_lock(*mutex)))
> >              return AVERROR(err);
> >
> > @@ -100,8 +86,7 @@ static int default_lockmgr_cb(void **arg, enum AVLockOp op)
> >      case AV_LOCK_DESTROY:
> >          if (*mutex)
> >              pthread_mutex_destroy(*mutex);
> > -        av_free(*mutex);
> > -        avpriv_atomic_ptr_cas(mutex, *mutex, NULL);
> > +
> >          return 0;
> >      }
> >      return 1;
> > @@ -114,8 +99,12 @@ static int (*lockmgr_cb)(void **mutex, enum AVLockOp op) = NULL;
> >
> >  volatile int ff_avcodec_locked;
> >  static int volatile entangled_thread_counter = 0;
> > -static void *codec_mutex;
> > -static void *avformat_mutex;
> > +
> > +static pthread_mutex_t codec_mutex_real = PTHREAD_MUTEX_INITIALIZER;
> > +static void *codec_mutex = &codec_mutex_real;
> > +
> > +static pthread_mutex_t avformat_mutex_real = PTHREAD_MUTEX_INITIALIZER;
> > +static void *avformat_mutex = &avformat_mutex_real;
> >
> >  #if FF_API_FAST_MALLOC && CONFIG_SHARED && HAVE_SYMVER
> >  FF_SYMVER(void*, av_fast_realloc, (void *ptr, unsigned int *size, size_t min_size), "LIBAVCODEC_55")
> 
> Static initialization doesn't work with the w32threads compat wrapper,
> and as such, this patch would break this use-case.

So why doesn't libavcodec use one of the pthread implementations for
windows?