in reply to Cleaning up a path

Well, if you're not worried about portablity:


!/usr/bin/perl

use strict;
use warnings;

my $somepath = "/var/log/../../home/poletti/../../etc/passwd";
my( @true );

foreach( split( /\//, $somepath ) ) {
    $_ eq ".." ? pop( @true ) : push( @true, $_ );
}
print join( '/', @true ), "\n";

[download]

Let the golf begin

-derby

Replies are listed 'Best First'.
(golf): Cleaning up a path
by Roy Johnson (Monsignor) on Apr 13, 2005 at 18:29 UTC 
    1while s#[^/]+/..(/|$)##

    [download]
    ikegami's remarks still apply.
    Caution: Contents may have been coded under pressure.
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[d/l]

      aye, works great (if you canonise first)

      sub remove_dot_dot_roy_edited {
   local $_ = $_[0];
   $_ = File::Spec::Unix->canonpath($_);
   1while s#[^/]+/..(/|$)##;
   return length($_) ? $_ : '.';
}

      [download]
[reply]
[d/l]
Re^2: Cleaning up a path
by ikegami (Patriarch) on Apr 13, 2005 at 17:52 UTC

    While that works for

    /foo/../bar          -> /bar
foo/../bar           -> bar
/foo/bar/../../moo   -> /moo
/var/log/../../home/poletti/../../etc/passwd -> /etc/passwd

    [download]

    it doesn't work for

    /foo/..              ->           <- Should be /
foo/..               ->           <- Should be . (?)
..                   ->           <- Should be ..
../foo               -> foo       <- Should be ../foo
../foo/bar           -> foo/bar   <- Should be ../foo/bar
foo/bar/../..        ->           <- Should be . (?)
/foo/bar/../..       ->           <- Should be /

    [download]
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[d/l]
[select]
Re^2: Cleaning up a path
by polettix (Vicar) on Apr 13, 2005 at 18:00 UTC
    This breaks in the case depicted by ikegami, but can be adjusted to cope with the portability problem: 
    #!/usr/bin/perl

use strict;
use warnings;
use File::Spec;

my $somepath = "/var/log/../../home/poletti/../../etc/rc.d";

my @true;
$somepath = "/../../../";
# Let's pretend $somepath is a directory... or is it? :)
/^\.\./ ? pop( @true ) : push( @true, $_ )
  foreach( File::Spec->splitdir($somepath) );
print File::Spec->catdir(@true), "\n";

    [download]

    Flavio (perl -e "print(scalar(reverse('ti.xittelop@oivalf')))")

    Don't fool yourself.
[reply]
[d/l]
      /foo/..              -> /            <- Fixed
/foo/../bar          -> /bar         <- Still works
foo/..               ->              <- Should be . (?)
foo/../bar           -> bar          <- Still works
..                   ->              <- Should be ..
../foo               -> foo          <- Should be ../foo
../foo/bar           -> foo/bar      <- Should be ../foo/bar
foo/bar/../..        ->              <- Should be . (?)
/foo/bar/../..       -> /            <- Fixed
/foo/bar/../../moo   -> /moo         <- Still works
{...}/etc/passwd     -> /etc/passwd  <- Still works

      [download]
[reply]
[d/l]
        Correct, but I did not dare asking for some solution which could be valid for relative filenames: this would be some kind of sphere reading!

        Just before you reply (I can hear your breath on my neck!), I want to admit that it also fails miserably with this valid, absolute path: 

        /..       ->     <- still broken

        [download]
        I'm understanding proper testing these days...

        Flavio (perl -e "print(scalar(reverse('ti.xittelop@oivalf')))")

        Don't fool yourself.
[reply]
[d/l]

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