[FFmpeg-devel] [PATCH] avio: Check for FF_NETERROR(EAGAIN) in retry_transfer_wrapper

[Ronald S. Bultje]

Hi,

On Sat, Feb 19, 2011 at 1:17 PM, Martin Storsj? <martin at martin.st> wrote:
> On Thu, 17 Feb 2011, Ronald S. Bultje wrote:
>
>> Hi,
>>
>> On Thu, Feb 17, 2011 at 11:22 AM, Martin Storsj? <martin at martin.st> wrote:
>> > On Thu, 17 Feb 2011, Nicolas George wrote:
>> >
>> >> Le nonidi 29 pluvi?se, an CCXIX, Luca Barbato a ?crit?:
>> >> > It would mean repeat that for every network protocol, might worth a try
>> >> > though.
>> >>
>> >> All (almost?) protocols use the ff_neterrno() macro, which is defined, on
>> >> windows, as:
>> >>
>> >> #define ff_neterrno() (-WSAGetLastError())
>> >>
>> >> It could become:
>> >>
>> >> static inline int ff_neterrno(void)
>> >> {
>> >> ? ? int err = -WSAGetLastError();
>> >> ? ? return err == -WSAEWOULDBLOCK ? AVERROR(EAGAIN) : err;
>> >> }
>> >>
>> >> This would become a good place for similar mappings should they become
>> >> necessary in the future.
>> >
>> > If this change is done, all uses of FF_NETERROR(EAGAIN) need to be
>> > switched to AVERROR(EAGAIN) at the same time.
>>
>> Sounds good to me, I've always disliked this FF_NETERROR() thing, it's
>> just very prone to stupid bugs that we can't really find because
>> they're win32-only and error-only.
>
> Indeed, getting rid of this would be great. However, that requires us to
> add mappings in ff_neterrno() for all the network errors that we want to
> catch via AVERROR(), that could lead to similar sublte bugs.
>
> What's worse, though, is that we use EPROTONOSUPPORT, ETIMEDOUT and
> ECONNREFUSED, too, and these ones don't exist in windows errno.h, only in
> the WSA-prefixed versions, so there's no header-provided value that we can
> map them to.

Can we map them to self-defined error codes on Windows? Made-up
values, is what I mean. I know that won't act well with strerror(),
but there isn't really an ideal solution for this.

> What do you think about this, is it worth fixing it this way, while still
> leaving a few cases of FF_NETERROR() scattered around for the errors that
> don't have a non-WSA-prefixed version in the windows errno.h?

Ideally we'd kill FF_NETERROR() completely.

Ronald