Re: [O] Re: Using babel to generate a commit log

[Nick Dokos]

Luke Crook <address@hidden> wrote:

> Nick Dokos <nicholas.dokos <at> hp.com> writes:
> 
> > 
> > Luke Crook <luke <at> balooga.com> wrote:
> > 
> > > Jambunathan K <kjambunathan <at> gmail.com> writes:
> > > 
> > > > 
> > > 
> > > I changed my code to wait until the 'Git' process completes. Luckily "vc-
> call-
> > > backend" returns the async process.
> > > 
> > 
> > ... or you could use a sentinel 
> > 
> > One bit of defensive programming might be to check that status *is* a
> > process before you do the wait: vc-do-command returns a real status in
> > the synchronous case, so if you cut-n-paste this code with some other
> > command that does not use async, it'll blow up.
> > 
> 
> I have modified the code to only check the status if the process is actually 
> running;
> 
>         (with-temp-buffer 
>           (let ((status (vc-call-backend backend
>                                            'print-log
>                                            files
>                                            (current-buffer))))
>           (when (= 0 (process-exit-status status))
>               (while (not (eq 'exit (process-status status)))
>                  (sit-for 1 t)))
> 

I meant something like this:

  (if (processp status)
     ...do the process stuff)
  
It's not a problem here since vc-call-backend will always call print-log
asynchronously, so status will always be a process, but if you use this
code somewhere else with a different command that is *not* done
asynchronously, then you'll have a problem. Not a biggie.

> I'm not sure about using a sentinel though as this is just a callback that is 
> executed when the process completes. Wouldn't the sentinel fire after the 
> source 
> block has returned?
> 
> Or do you mean to wait until a variable set by the sentinel returns t?
> 

Something like the latter: just something to avoid the busy-wait loop,
but again it's a minor nit - the loop works just fine.

Nick