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avformat: use mutexes instead of atomics in av_register_{input,output}_format()

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Reviewed-by: wm4 <nfxjfg@googlemail.com>
Signed-off-by: James Almer <jamrial@gmail.com>
This commit is contained in:
James Almer 2018-01-04 15:12:53 -03:00
parent 9ed4ebc530
commit 57960b1f28
1 changed files with 23 additions and 11 deletions
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34
libavformat/format.c
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@ -19,10 +19,10 @@
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
#include "libavutil/atomic.h"
#include "libavutil/avstring.h"
#include "libavutil/bprint.h"
#include "libavutil/opt.h"
#include "libavutil/thread.h"
#include "avio_internal.h"
#include "avformat.h"
@ -58,28 +58,40 @@ AVOutputFormat *av_oformat_next(const AVOutputFormat *f)
return first_oformat;
}
static AVMutex iformat_register_mutex = AV_MUTEX_INITIALIZER;
void av_register_input_format(AVInputFormat *format)
{
AVInputFormat **p = last_iformat;
AVInputFormat **p;
// Note, format could be added after the first 2 checks but that implies that *p is no longer NULL
while(p != &format->next && !format->next && avpriv_atomic_ptr_cas((void * volatile *)p, NULL, format))
ff_mutex_lock(&iformat_register_mutex);
p = last_iformat;
while (*p)
p = &(*p)->next;
if (!format->next)
*p = format;
format->next = NULL;
last_iformat = &format->next;
ff_mutex_unlock(&iformat_register_mutex);
}
static AVMutex oformat_register_mutex = AV_MUTEX_INITIALIZER;
void av_register_output_format(AVOutputFormat *format)
{
AVOutputFormat **p = last_oformat;
AVOutputFormat **p;
// Note, format could be added after the first 2 checks but that implies that *p is no longer NULL
while(p != &format->next && !format->next && avpriv_atomic_ptr_cas((void * volatile *)p, NULL, format))
ff_mutex_lock(&oformat_register_mutex);
p = last_oformat;
while (*p)
p = &(*p)->next;
if (!format->next)
*p = format;
format->next = NULL;
last_oformat = &format->next;
ff_mutex_unlock(&oformat_register_mutex);
}
int av_match_ext(const char *filename, const char *extensions)