avcodec/avcodec, avpacket: Return blank packet on av_packet_ref() failure

Up until now, it was completely unspecified what the content of the
destination packet dst was on error. Depending upon where the error
happened calling av_packet_unref() on dst might be dangerous.

This commit changes this by making sure that dst is blank on error, so
unreferencing it again is safe (and still pointless). This behaviour is
documented.

Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@gmail.com>
This commit is contained in:
Andreas Rheinhardt 2020-03-27 01:56:38 +01:00
parent e621f2b6cd
commit c52ec0367d
4 changed files with 11 additions and 5 deletions

View File

@ -15,6 +15,10 @@ libavutil: 2017-10-21
API changes, most recent first:
2020-03-27 - xxxxxxxxxx - lavc 58.77.100 - avcodec.h
av_packet_ref() now guarantees to return the destination packet
in a blank state on error.
2020-03-10 - xxxxxxxxxx - lavc 58.75.100 - avcodec.h
Add AV_PKT_DATA_ICC_PROFILE.

View File

@ -4651,7 +4651,8 @@ void av_packet_free_side_data(AVPacket *pkt);
* @param dst Destination packet. Will be completely overwritten.
* @param src Source packet
*
* @return 0 on success, a negative AVERROR on error.
* @return 0 on success, a negative AVERROR on error. On error, dst
* will be blank (as if returned by av_packet_alloc()).
*/
int av_packet_ref(AVPacket *dst, const AVPacket *src);

View File

@ -610,12 +610,13 @@ int av_packet_ref(AVPacket *dst, const AVPacket *src)
{
int ret;
dst->buf = NULL;
ret = av_packet_copy_props(dst, src);
if (ret < 0)
return ret;
goto fail;
if (!src->buf) {
dst->buf = NULL;
ret = packet_alloc(&dst->buf, src->size);
if (ret < 0)
goto fail;
@ -637,7 +638,7 @@ int av_packet_ref(AVPacket *dst, const AVPacket *src)
return 0;
fail:
av_packet_free_side_data(dst);
av_packet_unref(dst);
return ret;
}

View File

@ -28,7 +28,7 @@
#include "libavutil/version.h"
#define LIBAVCODEC_VERSION_MAJOR 58
#define LIBAVCODEC_VERSION_MINOR 76
#define LIBAVCODEC_VERSION_MINOR 77
#define LIBAVCODEC_VERSION_MICRO 100
#define LIBAVCODEC_VERSION_INT AV_VERSION_INT(LIBAVCODEC_VERSION_MAJOR, \