bug#6995: 24.0.50; get-free-disk-space doesn't return available space in dired

[Thierry Volpiatto <thierry.volpiatto@gmail.com>]

Stefan Monnier <monnier@iro.umontreal.ca> writes:

>> How about dropping the use of `df', at least on GNU/Linux?  It's IMO
>> ridiculous to invoke an external program for a single system call.  I
>> know that this system call is notoriously non-portable, and that doing
>> in Emacs all that system-dependent stuff that `df' does is not a good
>> idea.  But at least on the most popular free system (and perhaps on a
>> few compatible ones) we could do it right without all that labor, and
>> gain stability and reliability that depending on `df' will never
>> achieve.
>
> That would make a lot of sense, yes,

I agree too, but waiting such a change, you should rewrite
`get-free-disk-space' as it can't work correctly on the output of df.

,----
| 	    ;; Usual format is as follows:
| 	    ;; Filesystem ...    Used  Available  Capacity ...
| 	    ;; /dev/sda6  ...48106535   35481255  10669850 ...
| 	    (goto-char (point-min))
| 	    (when (re-search-forward " +Avail[^ \n]*"
`----

But usual format is not the same on all locales:
Here it is:

,----
| Sys. de fichiers    1024-blocs   Utilisé    Dispo. Capacité Monté sur
| /dev/sda7             48947688  21618816  24842416      47% /home
`----

So (re-search-forward " +Avail[^ \n]*" is not portable here.

I use this simplified version of get-free-disk-space if it can help:

,----
| (defun get-free-disk-space (dir)
|   (let* ((data   (with-temp-buffer
|                    (call-process directory-free-space-program
|                                  nil t nil
|                                  directory-free-space-args
|                                  dir)
|                    (split-string (buffer-string) "\n" t)))
|          (values (cdr (split-string (second data)))))
|     (nth 2 values)))
`----

Tough the version on 23.2 work also.

Note that the value of "total used in directory" is always wrong.
How do you get this value?

-- 
A+ Thierry
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