[FFmpeg-devel] [PATCH 1/2] avformat/aviobuf: Remove AVIOInternal and one level of indirection

Paul B Mahol onemda at gmail.com
Thu Jan 30 14:33:43 EET 2020


I guess it is fine, see no negative implications.

On 1/30/20, Andreas Rheinhardt <andreas.rheinhardt at gmail.com> wrote:
> Andreas Rheinhardt:
>> Andreas Rheinhardt:
>>> On Mon, Jan 6, 2020 at 3:51 PM Andreas Rheinhardt <
>>> andreas.rheinhardt at gmail.com> wrote:
>>>
>>>> In the Libav commit cae448cf, the opaque of every AVIOContext opened
>>>> by ffio_fdopen() (which is used internally by avio_open() and
>>>> avio_open2())
>>>> changed: It was a simple pointer to an URLContext before, but now it was
>>>> a structure (namely AVIOInternal) containing a pointer to an URLContext
>>>> as its only member. The next commits (namely 8c0ceafb and ec4c4839)
>>>> added
>>>> members to AVIOInternal to allow white-/blacklisting of protocols.
>>>>
>>>> But these two commits were never merged into FFmpeg (they were only
>>>> merged as no-ops in 510046c2 and 063b26d3), because FFmpeg chose
>>>> a different way to implement this (in 93629735); and so our AVIOInternal
>>>> still has exactly one member.
>>>>
>>>> This of course means that it is unnecessary to use AVIOInternal as
>>>> opaque as it is just adding a level of indirection (not only pointer
>>>> dereference, but also wrapper functions). Therefore this commit
>>>> removes AVIOInternal entirely and essentially reverts cae448cf.
>>>>
>>>> Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt at gmail.com>
>>>> ---
>>>>  libavformat/aviobuf.c | 86 ++++++++-----------------------------------
>>>>  1 file changed, 15 insertions(+), 71 deletions(-)
>>>>
>>>> diff --git a/libavformat/aviobuf.c b/libavformat/aviobuf.c
>>>> index 70e1d2ca10..0e2f038988 100644
>>>> --- a/libavformat/aviobuf.c
>>>> +++ b/libavformat/aviobuf.c
>>>> @@ -42,15 +42,10 @@
>>>>   */
>>>>  #define SHORT_SEEK_THRESHOLD 4096
>>>>
>>>> -typedef struct AVIOInternal {
>>>> -    URLContext *h;
>>>> -} AVIOInternal;
>>>> -
>>>>  static void *ff_avio_child_next(void *obj, void *prev)
>>>>  {
>>>>      AVIOContext *s = obj;
>>>> -    AVIOInternal *internal = s->opaque;
>>>> -    return prev ? NULL : internal->h;
>>>> +    return prev ? NULL : s->opaque;
>>>>  }
>>>>
>>>>  static const AVClass *ff_avio_child_class_next(const AVClass *prev)
>>>> @@ -940,49 +935,8 @@ uint64_t ffio_read_varlen(AVIOContext *bc){
>>>>      return val;
>>>>  }
>>>>
>>>> -static int io_read_packet(void *opaque, uint8_t *buf, int buf_size)
>>>> -{
>>>> -    AVIOInternal *internal = opaque;
>>>> -    return ffurl_read(internal->h, buf, buf_size);
>>>> -}
>>>> -
>>>> -static int io_write_packet(void *opaque, uint8_t *buf, int buf_size)
>>>> -{
>>>> -    AVIOInternal *internal = opaque;
>>>> -    return ffurl_write(internal->h, buf, buf_size);
>>>> -}
>>>> -
>>>> -static int64_t io_seek(void *opaque, int64_t offset, int whence)
>>>> -{
>>>> -    AVIOInternal *internal = opaque;
>>>> -    return ffurl_seek(internal->h, offset, whence);
>>>> -}
>>>> -
>>>> -static int io_short_seek(void *opaque)
>>>> -{
>>>> -    AVIOInternal *internal = opaque;
>>>> -    return ffurl_get_short_seek(internal->h);
>>>> -}
>>>> -
>>>> -static int io_read_pause(void *opaque, int pause)
>>>> -{
>>>> -    AVIOInternal *internal = opaque;
>>>> -    if (!internal->h->prot->url_read_pause)
>>>> -        return AVERROR(ENOSYS);
>>>> -    return internal->h->prot->url_read_pause(internal->h, pause);
>>>> -}
>>>> -
>>>> -static int64_t io_read_seek(void *opaque, int stream_index, int64_t
>>>> timestamp, int flags)
>>>> -{
>>>> -    AVIOInternal *internal = opaque;
>>>> -    if (!internal->h->prot->url_read_seek)
>>>> -        return AVERROR(ENOSYS);
>>>> -    return internal->h->prot->url_read_seek(internal->h, stream_index,
>>>> timestamp, flags);
>>>> -}
>>>> -
>>>>  int ffio_fdopen(AVIOContext **s, URLContext *h)
>>>>  {
>>>> -    AVIOInternal *internal = NULL;
>>>>      uint8_t *buffer = NULL;
>>>>      int buffer_size, max_packet_size;
>>>>
>>>> @@ -996,14 +950,10 @@ int ffio_fdopen(AVIOContext **s, URLContext *h)
>>>>      if (!buffer)
>>>>          return AVERROR(ENOMEM);
>>>>
>>>> -    internal = av_mallocz(sizeof(*internal));
>>>> -    if (!internal)
>>>> -        goto fail;
>>>> -
>>>> -    internal->h = h;
>>>> -
>>>> -    *s = avio_alloc_context(buffer, buffer_size, h->flags &
>>>> AVIO_FLAG_WRITE,
>>>> -                            internal, io_read_packet, io_write_packet,
>>>> io_seek);
>>>> +    *s = avio_alloc_context(buffer, buffer_size, h->flags &
>>>> AVIO_FLAG_WRITE, h,
>>>> +                            (int (*)(void *, uint8_t *, int))
>>>> ffurl_read,
>>>> +                            (int (*)(void *, uint8_t *, int))
>>>> ffurl_write,
>>>> +                            (int64_t (*)(void *, int64_t,
>>>> int))ffurl_seek);
>>>>      if (!*s)
>>>>          goto fail;
>>>>
>>>> @@ -1023,30 +973,28 @@ int ffio_fdopen(AVIOContext **s, URLContext *h)
>>>>      (*s)->max_packet_size = max_packet_size;
>>>>      (*s)->min_packet_size = h->min_packet_size;
>>>>      if(h->prot) {
>>>> -        (*s)->read_pause = io_read_pause;
>>>> -        (*s)->read_seek  = io_read_seek;
>>>> +        (*s)->read_pause = (int (*)(void *,
>>>> int))h->prot->url_read_pause;
>>>> +        (*s)->read_seek  =
>>>> +            (int64_t (*)(void *, int, int64_t,
>>>> int))h->prot->url_read_seek;
>>>>
>>>>          if (h->prot->url_read_seek)
>>>>              (*s)->seekable |= AVIO_SEEKABLE_TIME;
>>>>      }
>>>> -    (*s)->short_seek_get = io_short_seek;
>>>> +    (*s)->short_seek_get = (int (*)(void *))ffurl_get_short_seek;
>>>>      (*s)->av_class = &ff_avio_class;
>>>>      return 0;
>>>>  fail:
>>>> -    av_freep(&internal);
>>>>      av_freep(&buffer);
>>>>      return AVERROR(ENOMEM);
>>>>  }
>>>>
>>>>  URLContext* ffio_geturlcontext(AVIOContext *s)
>>>>  {
>>>> -    AVIOInternal *internal;
>>>>      if (!s)
>>>>          return NULL;
>>>>
>>>> -    internal = s->opaque;
>>>> -    if (internal && s->read_packet == io_read_packet)
>>>> -        return internal->h;
>>>> +    if (s->opaque && s->read_packet == (int (*)(void *, uint8_t *,
>>>> int))ffurl_read)
>>>> +        return s->opaque;
>>>>      else
>>>>          return NULL;
>>>>  }
>>>> @@ -1216,17 +1164,15 @@ int avio_open2(AVIOContext **s, const char
>>>> *filename, int flags,
>>>>
>>>>  int avio_close(AVIOContext *s)
>>>>  {
>>>> -    AVIOInternal *internal;
>>>>      URLContext *h;
>>>>
>>>>      if (!s)
>>>>          return 0;
>>>>
>>>>      avio_flush(s);
>>>> -    internal = s->opaque;
>>>> -    h        = internal->h;
>>>> +    h         = s->opaque;
>>>> +    s->opaque = NULL;
>>>>
>>>> -    av_freep(&s->opaque);
>>>>      av_freep(&s->buffer);
>>>>      if (s->write_flag)
>>>>          av_log(s, AV_LOG_VERBOSE, "Statistics: %d seeks, %d
>>>> writeouts\n",
>>>> s->seek_count, s->writeout_count);
>>>> @@ -1318,8 +1264,7 @@ int avio_read_to_bprint(AVIOContext *h, AVBPrint
>>>> *pb, size_t max_size)
>>>>  int avio_accept(AVIOContext *s, AVIOContext **c)
>>>>  {
>>>>      int ret;
>>>> -    AVIOInternal *internal = s->opaque;
>>>> -    URLContext *sc = internal->h;
>>>> +    URLContext *sc = s->opaque;
>>>>      URLContext *cc = NULL;
>>>>      ret = ffurl_accept(sc, &cc);
>>>>      if (ret < 0)
>>>> @@ -1329,8 +1274,7 @@ int avio_accept(AVIOContext *s, AVIOContext **c)
>>>>
>>>>  int avio_handshake(AVIOContext *c)
>>>>  {
>>>> -    AVIOInternal *internal = c->opaque;
>>>> -    URLContext *cc = internal->h;
>>>> +    URLContext *cc = c->opaque;
>>>>      return ffurl_handshake(cc);
>>>>  }
>>>>
>>>> --
>>>> 2.20.1
>>>>
>>>>
>>> Ping.
>>>
>>> - Andreas
>>>
>> Ping.
>>
>> - Andreas
>>
> Ping.
>
> - Andreas
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