Re: [PATCH] emacs: Use socket instead of port.

[ludo@gnu.org (Ludovic Courtès)]

Alex Kost <alezost@gmail.com> skribis:

> Hm, but it doesn't delete the socket after the quit, right?  At least,
> it doesn't when I tried "guile -l /tmp/repl-server.scm" with the
> following "/tmp/repl-server.scm":
>
>
> (use-modules (system repl server))
>
> (let ((socket "/tmp/s1"))
>   (call-with-new-thread
>    (lambda ()
>      (dynamic-wind
>        (const #t)
>        (lambda ()
>          (run-server (make-unix-domain-server-socket #:path socket)))
>        (lambda ()
>          (false-if-exception (delete-file socket)))))))
>
>
> And after ",q" the file "/tmp/s1" stayed.

Right, in that case, the thread is not properly terminated so it doesn’t
have a chance to run its dynwind handler.

Hmm, that sucks.

>> It may be good to fix it upfront though.  WDYT?
>
> Sorry, I don't understand.

I meant that we should probably fix this lingering socket problem before
committing the change.

> Anyway, as I mentioned in the reply to Florian, I think the best would
> be to add a procedure for deleting socket file to `kill-emacs-hook' (as
> in the attached updated patch).  This should prevent appearing dead
> sockets.

Indeed, sounds even better!

> P.S.  Maybe it's a wrong impression, but it looks (to me) that
> connecting to a socket is significantly faster than using a port (so all
> this Guix REPL stuff starts faster).

Hmm I don’t think it should be noticeably faster.  But it’s definitely
better because socket nodes are not a scarce/global resource (unlike TCP
ports), and they are integrated with the Unix file permission model.

> From d6903c7c115809cf88f892e78785d920ff80184d Mon Sep 17 00:00:00 2001
> From: Alex Kost <alezost@gmail.com>
> Date: Sat, 12 Dec 2015 11:23:03 +0300
> Subject: [PATCH] emacs: Use socket instead of port.
>
> Suggested by Florian Paul Schmidt.
>
> * emacs/guix-backend.el (guix-default-port): Remove.
>   (guix-repl-socket-file-name-function, guix-repl-current-socket): New
>   variables.
>   (guix-repl-socket-file-name, guix-repl-delete-socket-maybe): New
>   procedures.
>   (guix-get-guile-program): Take socket as an optional argument.
>   (guix-start-repl-maybe): Adjust accordingly.

LGTM, thanks!

Ludo’.