[FFmpeg-devel] [PATCH 1/2] avformat/wtvdec: Forward errors when reading packet

[Michael Niedermayer]

On Wed, Feb 19, 2020 at 08:16:03PM +1100, Peter Ross wrote:
> On Tue, Feb 18, 2020 at 12:36:00PM +0000, Andreas Rheinhardt wrote:
> > Andreas Rheinhardt:
> > > wtvfile_read_packet did not abide by the requirements of an
> > > AVIOContext's read_packet-function: If it did not read anything,
> > > it returned zero, which currently leads to a warning in read_packet_wrapper
> > > in aviobuf.c. Said warning will be an av_assert2 as soon as
> > > FF_API_OLD_AVIO_EOF_0 is zero (probably the next major version bump).
> > > So instead forward the error code from the underlying protocol.
> > > 
> > > This error/assert is triggered in the wtv-demux FATE test.
> > > 
> > > Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt at gmail.com>
> > > ---
> > > This patch supersedes [1]. The difference to the previous version is
> > > that I have changed the return value from "nread ? nread : n ? :
> > > AVERROR_EOF" to "nread ? nread : n". This can only make a difference if
> > > buf_size (the size of the data to be read) is zero and I now think that
> > > this should simply not happen: It would be possible by calling
> > > avio_read_partial with a desired size of 0 and if the AVIOContext's
> > > write_flag is set, but avio_read_partial is not called with one of
> > > wtvdec's custom AVIOContexts (not to mention that if this were a
> > > problem, it should probably be fixed in avio_read_partial).
> > > 
> > > [1]: https://patchwork.ffmpeg.org/project/ffmpeg/patch/20190821090438.10260-4-andreas.rheinhardt@gmail.com/
> > > 
> > >  libavformat/wtvdec.c | 5 ++---
> > >  1 file changed, 2 insertions(+), 3 deletions(-)
> > > 
> > > diff --git a/libavformat/wtvdec.c b/libavformat/wtvdec.c
> > > index 67d934f074..83f510b92f 100644
> > > --- a/libavformat/wtvdec.c
> > > +++ b/libavformat/wtvdec.c
> > > @@ -71,7 +71,7 @@ static int wtvfile_read_packet(void *opaque, uint8_t *buf, int buf_size)
> > >  {
> > >      WtvFile *wf = opaque;
> > >      AVIOContext *pb = wf->pb_filesystem;
> > > -    int nread = 0;
> > > +    int nread = 0, n = 0;
> > >  
> > >      if (wf->error || pb->error)
> > >          return -1;
> > > @@ -80,7 +80,6 @@ static int wtvfile_read_packet(void *opaque, uint8_t *buf, int buf_size)
> > >  
> > >      buf_size = FFMIN(buf_size, wf->length - wf->position);
> > >      while(nread < buf_size) {
> > > -        int n;
> > >          int remaining_in_sector = (1 << wf->sector_bits) - (wf->position & ((1 << wf->sector_bits) - 1));
> > >          int read_request        = FFMIN(buf_size - nread, remaining_in_sector);
> > >  
> > > @@ -100,7 +99,7 @@ static int wtvfile_read_packet(void *opaque, uint8_t *buf, int buf_size)
> > >              }
> > >          }
> > >      }
> > > -    return nread;
> > > +    return nread ? nread : n;
> > >  }
> > >  
> > >  /**
> > > 
> > 
> > Ping.
> 
> looks good. please apply.

will apply

thx

[...]

-- 
Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

During times of universal deceit, telling the truth becomes a
revolutionary act. -- George Orwell
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