From: Erik Faye-Lund <kusmabite@googlemail.com>
Date: Fri, 27 Nov 2009 14:39:39 GMT
Subject: Re: [msysGit] [PATCH/RFC 07/11] run-command: support input-fd
Message-ID: <40aa078e0911270639n1de36517w5fdf6ef38e931b19@mail.gmail.com>
In-Reply-To: <200911262253.59641.j6t@kdbg.org>

On Thu, Nov 26, 2009 at 10:53 PM, Johannes Sixt <j6t@kdbg.org> wrote:
> On Donnerstag, 26. November 2009, Erik Faye-Lund wrote:
>> @@ -327,7 +327,10 @@ int start_async(struct async *async)
>>  {
>>       int pipe_out[2];
>>
>> -     if (pipe(pipe_out) < 0)
>> +     if (async->out) {
>> +             pipe_out[0] = dup(async->out);
>> +             pipe_out[1] = dup(async->out);
>> +     } else if (pipe(pipe_out) < 0)
>>               return error("cannot create pipe: %s", strerror(errno));
>>       async->out = pipe_out[0];
>
> Hm. If async->out != 0:
>
>        pipe_out[0] = dup(async->out);
>        async->out = pipe_out[0];
>
> This is confusing.

What do you find confusing about it? The idea is to use a provided
bi-directional fd instead of a pipe if async->out is non-zero. The
currently defined rules for async is that async->out must be zero
(since the structure should be zero-initialized).

> Moreover, you are assigning (a dup of) the same fd to the writable end. This
> assumes a bi-directional channel. I don't yet know what I should think about
> this (haven't studied the later patches, yet).
>

Indeed it does. Do we want to extend it to support a set of
unidirectional channels instead?

> It would be great if you could add a few words to
> Documentation/technical/api-runcommand.txt.
>

Ah, yes. I know I should update the documentation and all, I'm just
usually really bad (*cough* lazy *cough*) at documenting stuff. But
I'll give it a go and if people hate what I write, they can suggest
changes.

-- 
Erik "kusma" Faye-Lund