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From: Maxime Devos <maximedevos@telenet.be>
To: Andrew Tropin <andrew@trop.in>, 54762@debbugs.gnu.org
Subject: [bug#54762] [PATCH] home: symlink-manager: Use no-follow version of file-exists?.
Date: Thu, 07 Apr 2022 20:21:35 +0200	[thread overview]
Message-ID: <be6efed627587bf2a962db2f76615b8de538c2ba.camel@telenet.be> (raw)
In-Reply-To: <87bkxc6d5t.fsf@trop.in>

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Andrew Tropin schreef op do 07-04-2022 om 20:01 [+0300]:
> Idk how file-exists? works internally, but still expect it to be more
> efficient than lstat.  That's why I decided to use lstat only as a
> "fallback" option in `or` statement.

Here's the definition, from module/ice-9/boot-9.scm (Guile source
code):

;; For reference, Emacs file-exists-p uses stat in this same way.
(define file-exists?
  (if (provided? 'posix)
      (lambda (str)
        (->bool (stat str #f)))
      [non-POSIX code that's not relevant to Guix]))

'file-exists?' just calls 'stat', a variant of 'lstat', so I don't
think there are performance gains to be had here.  Well, the
(stat ... #f) might not need to install an exception handler since it
is written in C, but that seems at most a micro-optimisation to me.

Greetings,
Maxime.

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  parent reply	other threads:[~2022-04-07 18:22 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-04-07  8:22 [bug#54762] [PATCH] home: symlink-manager: Use no-follow version of file-exists? Andrew Tropin
2022-04-07 12:28 ` Maxime Devos
2022-04-07 17:01   ` Andrew Tropin
2022-04-07 18:17     ` Maxime Devos
2022-04-07 18:21     ` Maxime Devos [this message]
2022-04-08  4:23       ` Andrew Tropin
2022-04-09 21:57         ` bug#54762: " Ludovic Courtès
2022-04-11  5:26           ` [bug#54762] " Andrew Tropin

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