[FFmpeg-devel] [PATCH] avformat/dashenc: Only use temporary files when outputting to file protocol

[Michael Niedermayer]

On Tue, Feb 14, 2017 at 10:18:02PM +0800, Steven Liu wrote:
> 2017-02-14 21:14 GMT+08:00 Thomas Stephens <thomas at ustudio.com>:
> 
> > Has anybody had a chance to look at this patch?
> >
> > Thanks,
> > --Thomas
> >
> > On Tue, Feb 7, 2017, 2:20 PM Thomas Stephens <thomas at ustudio.com> wrote:
> >
> > > Skips using temporary files when outputting to a protocol other than
> > > "file", which enables dash to output content over network
> > > protocols. The logic has been copied from the HLS format.
> > > ---
> > >  libavformat/dashenc.c | 29 +++++++++++++++++++++++------
> > >  1 file changed, 23 insertions(+), 6 deletions(-)
> > >
> > > diff --git a/libavformat/dashenc.c b/libavformat/dashenc.c
> > > index 534fa75..fa56505 100644
> > > --- a/libavformat/dashenc.c
> > > +++ b/libavformat/dashenc.c
> > > @@ -444,9 +444,15 @@ static int write_manifest(AVFormatContext *s, int
> > > final)
> > >      AVIOContext *out;
> > >      char temp_filename[1024];
> > >      int ret, i;
> > > +    const char *proto = avio_find_protocol_name(s->filename);
> > > +    int use_rename = proto && !strcmp(proto, "file");
> > > +    static unsigned int warned_non_file = 0;
> > >      AVDictionaryEntry *title = av_dict_get(s->metadata, "title", NULL,
> > 0);
> > >
> > > -    snprintf(temp_filename, sizeof(temp_filename), "%s.tmp",
> > s->filename);
> > > +    if (!use_rename && !warned_non_file++)
> > > +        av_log(s, AV_LOG_ERROR, "Cannot use rename on non file protocol,
> > > this may lead to races and temporary partial files\n");
> > > +
> > > +    snprintf(temp_filename, sizeof(temp_filename), use_rename ? "%s.tmp"
> > > : "%s", s->filename);
> > >      ret = s->io_open(s, &out, temp_filename, AVIO_FLAG_WRITE, NULL);
> > >      if (ret < 0) {
> > >          av_log(s, AV_LOG_ERROR, "Unable to open %s for writing\n",
> > > temp_filename);
> > > @@ -548,7 +554,11 @@ static int write_manifest(AVFormatContext *s, int
> > > final)
> > >      avio_printf(out, "</MPD>\n");
> > >      avio_flush(out);
> > >      ff_format_io_close(s, &out);
> > > -    return avpriv_io_move(temp_filename, s->filename);
> > > +
> > > +    if (use_rename)
> > > +        return avpriv_io_move(temp_filename, s->filename);
> > > +
> > > +    return 0;
> > >  }
> > >
> > >  static int dash_init(AVFormatContext *s)
> > > @@ -796,6 +806,10 @@ static int dash_flush(AVFormatContext *s, int final,
> > > int stream)
> > >  {
> > >      DASHContext *c = s->priv_data;
> > >      int i, ret = 0;
> > > +
> > > +    const char *proto = avio_find_protocol_name(s->filename);
> > > +    int use_rename = proto && !strcmp(proto, "file");
> > > +
> > >      int cur_flush_segment_index = 0;
> > >      if (stream >= 0)
> > >          cur_flush_segment_index = c->streams[stream].segment_index;
> > > @@ -833,7 +847,7 @@ static int dash_flush(AVFormatContext *s, int final,
> > > int stream)
> > >          if (!c->single_file) {
> > >              dash_fill_tmpl_params(filename, sizeof(filename),
> > > c->media_seg_name, i, os->segment_index, os->bit_rate, os->start_pts);
> > >              snprintf(full_path, sizeof(full_path), "%s%s", c->dirname,
> > > filename);
> > > -            snprintf(temp_path, sizeof(temp_path), "%s.tmp", full_path);
> > > +            snprintf(temp_path, sizeof(temp_path), use_rename ? "%s.tmp"
> > > : "%s", full_path);
> > >              ret = s->io_open(s, &os->out, temp_path, AVIO_FLAG_WRITE,
> > > NULL);
> > >              if (ret < 0)
> > >                  break;
> > > @@ -851,9 +865,12 @@ static int dash_flush(AVFormatContext *s, int final,
> > > int stream)
> > >              find_index_range(s, full_path, start_pos, &index_length);
> > >          } else {
> > >              ff_format_io_close(s, &os->out);
> > > -            ret = avpriv_io_move(temp_path, full_path);
> > > -            if (ret < 0)
> > > -                break;
> > > +
> > > +            if (use_rename) {
> > > +                ret = avpriv_io_move(temp_path, full_path);
> > > +                if (ret < 0)
> > > +                    break;
> > > +            }
> > >          }
> > >          add_segment(os, filename, os->start_pts, os->max_pts -
> > > os->start_pts, start_pos, range_length, index_length);
> > >          av_log(s, AV_LOG_VERBOSE, "Representation %d media segment %d
> > > written to: %s\n", i, os->segment_index, full_path);
> > > --
> > > 2.5.0
> > >
> > >
> > _______________________________________________
> > ffmpeg-devel mailing list
> > ffmpeg-devel at ffmpeg.org
> > http://ffmpeg.org/mailman/listinfo/ffmpeg-devel
> >
> 
> 
> LGTM

will apply

thx

[...]
--
Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

Breaking DRM is a little like attempting to break through a door even
though the window is wide open and the only thing in the house is a bunch
of things you dont want and which you would get tomorrow for free anyway
-------------- next part --------------
A non-text attachment was scrubbed...
Name: signature.asc
Type: application/pgp-signature
Size: 181 bytes
Desc: Digital signature
URL: <http://ffmpeg.org/pipermail/ffmpeg-devel/attachments/20170214/33d1e24b/attachment.sig>