Re: [MacPerl] Determining free disk space

[Chris Nandor <pudge@pobox.com>]

At 8:55 -0500 1999.10.11, Jefferson R. Lowrey wrote:
>At 10:34 AM +0200 10/11/99, Ian wrote:
>>Hi
>>
>>I've had a look at CPAN, the FAQ, and searched the mailing list archive, but
>>with no joy. I'd like to write a simple script that runs as a cron job and
>>checks the space remaining on all the volumes on our server...if there's
>>less than a certain amount of space on one of the volumes it'll email the
>>sysadmin with the details.
>>
>>However, I can't find a way of finding out how much free space there is on a
>>mounted (or local) volume. There are a couple of Unix modules for this, but
>>evidently not for the Mac. Any clues?
>>
>
>Well.  This sounds like a job for glue...
>use strict;
>use Mac::Glue ':all';
>my $finder = new Mac::Glue 'Finder';
>
>my $freespace = $finder->get($finder->prop('free_space',disk => 'Jeff-HD'));
>
>print "$freespace\n";
>__END__
>
>But I'm not getting quite the result I'm looking for.  It sends the same AE
>as the corresponding AppleScript (another option)
>tell application "Finder"
>   get free space of disk "Jeff-HD"
>end tell
>
>but I get a result like
>comp(«0000000017402000»)
>
>So I don't think I'm coercing things right or using the right terminology
>somewhere.

There are two ways around it.

One is to add this code:

    local $Mac::AppleEvents::Simple::AE_GET{comp} = sub {
        (unpack 'll', shift()->data->get)[-1]
    };

This will unpack the double integer (which is what 'comp' stands for, I
believe).  I can add this code to a future version of the module or
something.

The other way is to ask for a double float:

    printf $finder->get(
        $finder->prop(free_space => disk => 'Bird'),
        as => 'doub'
    );

You can also do:

    $Mac::Types::MacUnpack{comp} = sub {
        (&Mac::Types::_Unpacker('ll')->(@_))[-1];
    };

Note that we take the last argument of the list returned by the two
unpacking routines.  I guess you should really concatenate the two values:

    join '', unpack 'll' ... ;

Would that be correct?  But if you did that, you could not use the
resulting number for math operations (unless the first number is 0, which
it will be in most cases).

-- 
Chris Nandor          mailto:pudge@pobox.com         http://pudge.net/
%PGPKey = ('B76E72AD', [1024, '0824090B CE73CA10  1FF77F13 8180B6B6'])

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