[FFmpeg-devel] [PATCH] avcodec/utils: use a default lock manager that uses a pthread mutex
Michael Niedermayer
michaelni at gmx.at
Fri Oct 18 21:04:47 CEST 2013
That makes avformat & avcodec thread safe without the need to explicitly
register a lock manager.
Signed-off-by: Michael Niedermayer <michaelni at gmx.at>
---
libavcodec/utils.c | 50 +++++++++++++++++++++++++++++++++++++++++++++++++-
1 file changed, 49 insertions(+), 1 deletion(-)
diff --git a/libavcodec/utils.c b/libavcodec/utils.c
index 3832b81..735c8e0 100644
--- a/libavcodec/utils.c
+++ b/libavcodec/utils.c
@@ -56,9 +56,57 @@
# include <iconv.h>
#endif
+#if HAVE_PTHREADS
+#include <pthread.h>
+static int default_lockmgr_cb(void **arg, enum AVLockOp op)
+{
+ void * volatile * mutex = arg;
+ int err;
+
+ switch (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);
+
+ return 0;
+ case AV_LOCK_RELEASE:
+ if ((err = pthread_mutex_unlock(*mutex)))
+ return AVERROR(err);
+
+ return 0;
+ case AV_LOCK_DESTROY:
+ if (*mutex)
+ pthread_mutex_destroy(*mutex);
+ av_free(*mutex);
+ avpriv_atomic_ptr_cas(mutex, *mutex, NULL);
+ return 0;
+ }
+ return 1;
+}
+static int (*lockmgr_cb)(void **mutex, enum AVLockOp op) = default_lockmgr_cb;
+#else
+static int (*lockmgr_cb)(void **mutex, enum AVLockOp op) = NULL;
+#endif
+
+
volatile int ff_avcodec_locked;
static int volatile entangled_thread_counter = 0;
-static int (*lockmgr_cb)(void **mutex, enum AVLockOp op);
static void *codec_mutex;
static void *avformat_mutex;
--
1.7.9.5
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