[FFmpeg-devel] [PATCH] Use AVERROR(ENOSYS) when it makes sense

[Michael Niedermayer]

On Tue, Apr 13, 2010 at 04:41:15PM -0700, Howard Chu wrote:
> Michael Niedermayer wrote:
>> On Mon, Apr 12, 2010 at 12:42:05AM +0200, Stefano Sabatini wrote:
>>> On date Sunday 2010-04-11 23:33:15 +0200, Michael Niedermayer encoded:
>>>> On Sun, Apr 11, 2010 at 10:13:30PM +0200, Stefano Sabatini wrote:
>>>>> On date Saturday 2010-04-03 13:46:24 +0200, Stefano Sabatini encoded:
>>>>>> Hi, as in subject.
>>>>>> --
>>>>>> FFmpeg = Fucking and Fabulous Moronic Peaceful Elitarian Genius
>>>>>
>>>>>>  From e66cec2193ee289f742120f92db17f33e7651fba Mon Sep 17 00:00:00 
>>>>>> 2001
>>>>>> From: Stefano Sabatini<stefano.sabatini-lala at poste.it>
>>>>>> Date: Tue, 16 Mar 2010 22:48:37 +0100
>>>>>> Subject: [PATCH 2/5] Make url_seek() return AVERROR(ENOSYS) rather 
>>>>>> than AVERROR(EPIPE) in
>>>>>>   the case where the seek operation is not defined in the protocol
>>>>>>   handler.
>>>>>>
>>>>>> ---
>>>>>>   libavformat/avio.c |    2 +-
>>>>>>   1 files changed, 1 insertions(+), 1 deletions(-)
>>>>>>
>>>>>> diff --git a/libavformat/avio.c b/libavformat/avio.c
>>>>>> index af9e049..3fb64d1 100644
>>>>>> --- a/libavformat/avio.c
>>>>>> +++ b/libavformat/avio.c
>>>>>> @@ -201,7 +201,7 @@ int64_t url_seek(URLContext *h, int64_t pos, int 
>>>>>> whence)
>>>>>>       int64_t ret;
>>>>>>
>>>>>>       if (!h->prot->url_seek)
>>>>>> -        return AVERROR(EPIPE);
>>>>>> +        return AVERROR(ENOSYS);
>>>>>>       ret = h->prot->url_seek(h, pos, whence&  ~AVSEEK_FORCE);
>>>>>>       return ret;
>>>>>>   }
>>>>>> --
>>>>>> 1.7.0
>>>>>>
>>>>>
>>>>>>  From f11131bc3a2e08f46b291e4fa849e7e8c642c757 Mon Sep 17 00:00:00 
>>>>>> 2001
>>>>>> From: Stefano Sabatini<stefano.sabatini-lala at poste.it>
>>>>>> Date: Tue, 16 Mar 2010 23:08:32 +0100
>>>>>> Subject: [PATCH 3/5] Make url_fseek() return AVERROR(ENOSYS) rather 
>>>>>> than AVERROR(EPIPE) if
>>>>>>   the seek operation is not defined in the ByteIOContext.
>>>>>>
>>>>>> ---
>>>>>>   libavformat/aviobuf.c |    2 +-
>>>>>>   1 files changed, 1 insertions(+), 1 deletions(-)
>>>>>>
>>>>>> diff --git a/libavformat/aviobuf.c b/libavformat/aviobuf.c
>>>>>> index 37a6f6d..039b6d3 100644
>>>>>> --- a/libavformat/aviobuf.c
>>>>>> +++ b/libavformat/aviobuf.c
>>>>>> @@ -160,7 +160,7 @@ int64_t url_fseek(ByteIOContext *s, int64_t 
>>>>>> offset, int whence)
>>>>>>               return AVERROR_EOF;
>>>>>>           s->buf_ptr = s->buf_end + offset - s->pos;
>>>>>>       } else {
>>>>>> -        int64_t res = AVERROR(EPIPE);
>>>>>> +        int64_t res = AVERROR(ENOSYS);
>>>>>>
>>>>>>   #if CONFIG_MUXERS || CONFIG_NETWORK
>>>>>>           if (s->write_flag) {
>>>>>> --
>>>>>> 1.7.0
>>>>>>
>>>>>
>>>>>>  From 492f5063961b0d63fd6dda4404a107aa99484d40 Mon Sep 17 00:00:00 
>>>>>> 2001
>>>>>> From: Stefano Sabatini<stefano.sabatini-lala at poste.it>
>>>>>> Date: Tue, 16 Mar 2010 23:10:21 +0100
>>>>>> Subject: [PATCH 4/5] Make url_fsize() return AVERROR(ENOSYS) rather 
>>>>>> than AVERROR(EPIPE) if
>>>>>>   the seek operation is not defined in the ByteIOContext.
>>>>>>
>>>>>> ---
>>>>>>   libavformat/aviobuf.c |    2 +-
>>>>>>   1 files changed, 1 insertions(+), 1 deletions(-)
>>>>>>
>>>>>> diff --git a/libavformat/aviobuf.c b/libavformat/aviobuf.c
>>>>>> index 039b6d3..0c46327 100644
>>>>>> --- a/libavformat/aviobuf.c
>>>>>> +++ b/libavformat/aviobuf.c
>>>>>> @@ -197,7 +197,7 @@ int64_t url_fsize(ByteIOContext *s)
>>>>>>           return AVERROR(EINVAL);
>>>>>>
>>>>>>       if (!s->seek)
>>>>>> -        return AVERROR(EPIPE);
>>>>>> +        return AVERROR(ENOSYS);
>>>>>>       size = s->seek(s->opaque, 0, AVSEEK_SIZE);
>>>>>>       if(size<0){
>>>>>>           if ((size = s->seek(s->opaque, -1, SEEK_END))<  0)
>>>>>
>>>>> Ping.
>>>>
>>>> you are misusing ENOSYS
>>>
>>> This is possible, anyway how is EPIPE better than ENOSYS in this case?
>>>
>>> Please give some advice if you have any.
>>
>> ive none atm, just that i prefer to leave things as they are if they are
>> wrong before and afte the patch. And i didnt really think much about it
>> maybe EPIPE does make some sense dunno
>
> Leaving it EPIPE makes for some other headaches. Most of the code uses 
> ENOSYS for unimplemented functions, so using EPIPE here makes an awkward 
> inconsistency. Callers expect ENOSYS.

what is "here", the code above quotes 3 functions i dont see any immedeate
relation between any of them and your code

[...]

-- 
Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

The educated differ from the uneducated as much as the living from the
dead. -- Aristotle 
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