Re: [msysGit] [PATCH/RFC 07/11] run-command: support input-fd

On Thu, Nov 26, 2009 at 10:53 PM, Johannes Sixt [off-list ref] wrote:

On Donnerstag, 26. November 2009, Erik Faye-Lund wrote:

quoted

@@ -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