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

[Andreas Rheinhardt]

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