c't freeware shareware 1997/CT_SW_97.ISO/pc/software/entwickl/win95/pw32i306.exe/lib/findbin.pm

Text File | 1996-10-09 | 5KB | 233 lines

# FindBin.pm
#
# Copyright (c) 1995 Graham Barr & Nick Ing-Simmons. All rights reserved.
# This program is free software; you can redistribute it and/or modify it
# under the same terms as Perl itself.

=head1 NAME

FindBin - Locate directory of original perl script

=head1 SYNOPSIS

 use FindBin;
 use lib "$FindBin::Bin/../lib";

 or

 use FindBin qw($Bin);
 use lib "$Bin/../lib";

=head1 DESCRIPTION

Locates the full path to the script bin directory to allow the use
of paths relative to the bin directory.

This allows a user to setup a directory tree for some software with
directories E<lt>rootE<gt>/bin and E<lt>rootE<gt>/lib and then the above example will allow
the use of modules in the lib directory without knowing where the software
tree is installed.

If perl is invoked using the B<-e> option or the perl script is read from
C<STDIN> then FindBin sets both C<$Bin> and C<$RealBin> to the current
directory.

=head1 EXPORTABLE VARIABLES

 $Bin         - path to bin directory from where script was invoked
 $Script      - basename of script from which perl was invoked
 $RealBin     - $Bin with all links resolved
 $RealScript  - $Script with all links resolved

=head1 KNOWN BUGS

if perl is invoked as

   perl filename

and I<filename> does not have executable rights and a program called I<filename>
exists in the users C<$ENV{PATH}> which satisfies both B<-x> and B<-T> then FindBin
assumes that it was invoked via the C<$ENV{PATH}>.

Workaround is to invoke perl as

 perl ./filename

=head1 AUTHORS

Graham Barr E<lt>F<[e-mail]>E<gt>
Nick Ing-Simmons E<lt>F<[e-mail]>E<gt>

=head1 COPYRIGHT

Copyright (c) 1995 Graham Barr & Nick Ing-Simmons. All rights reserved.
This program is free software; you can redistribute it and/or modify it
under the same terms as Perl itself.

=head1 REVISION

$Revision: 1.4 $

=cut

package FindBin;
use Carp;
require 5.000;
require Exporter;
use Cwd qw(getcwd);

@EXPORT_OK = qw($Bin $Script $RealBin $RealScript $Dir $RealDir);
%EXPORT_TAGS = (ALL => [qw($Bin $Script $RealBin $RealScript $Dir $RealDir)]);
@ISA = qw(Exporter);

$VERSION = $VERSION = sprintf("%d.%02d", q$Revision: 1.4 $ =~ /(\d+)\.(\d+)/);

# Taken from Cwd.pm It is really getcwd with an optional
# parameter instead of '.'
#
# another way would be:
#
#sub abs_path
#{
# my $cwd = getcwd();
# chdir(shift || '.');
# my $realpath = getcwd();
# chdir($cwd);
# $realpath;
#}

sub abs_path
{
    my $start = shift || '.';
    my($dotdots, $cwd, @pst, @cst, $dir, @tst);

    unless (@cst = stat( $start ))
    {
    warn "stat($start): $!";
    return '';
    }
    $cwd = '';
    $dotdots = $start;
    do
    {
    $dotdots .= '/..';
    @pst = @cst;
    unless (opendir(PARENT, $dotdots))
    {
        warn "opendir($dotdots): $!";
        return '';
    }
    unless (@cst = stat($dotdots))
    {
        warn "stat($dotdots): $!";
        closedir(PARENT);
        return '';
    }
    if ($pst[0] == $cst[0] && $pst[1] == $cst[1])
    {
        $dir = '';
    }
    else
    {
        do
        {
        unless (defined ($dir = readdir(PARENT)))
            {
            warn "readdir($dotdots): $!";
            closedir(PARENT);
            return '';
        }
        $tst[0] = $pst[0]+1 unless (@tst = lstat("$dotdots/$dir"))
        }
        while ($dir eq '.' || $dir eq '..' || $tst[0] != $pst[0] ||
           $tst[1] != $pst[1]);
    }
    $cwd = "$dir/$cwd";
    closedir(PARENT);
    } while ($dir);
    chop($cwd); # drop the trailing /
    $cwd;
}


BEGIN
{
 *Dir = \$Bin;
 *RealDir = \$RealBin;

 if($0 eq '-e' || $0 eq '-')
  {
   # perl invoked with -e or script is on C<STDIN>

   $Script = $RealScript = $0;
   $Bin    = $RealBin    = getcwd();
  }
 else
  {
   my $script = $0;

   if ($^O eq 'VMS')
    {
     ($Bin,$Script) = VMS::Filespec::rmsexpand($0) =~ /(.*\])(.*)/;
     ($RealBin,$RealScript) = ($Bin,$Script);
    }
   else
    {
     unless($script =~ m#/# && -f $script)
      {
       my $dir;

       foreach $dir (split(/:/,$ENV{PATH}))
    {
    if(-x "$dir/$script")
         {
          $script = "$dir/$script";

      if (-f $0)
           {
        # $script has been found via PATH but perl could have
        # been invoked as 'perl file'. Do a dumb check to see
        # if $script is a perl program, if not then $script = $0
            #
            # well we actually only check that it is an ASCII file
            # we know its executable so it is probably a script
            # of some sort.

            $script = $0 unless(-T $script);
           }
          last;
         }
       }
     }

     croak("Cannot find current script '$0'") unless(-f $script);

     # Ensure $script contains the complete path incase we C<chdir>

     $script = getcwd() . "/" . $script unless($script =~ m,^/,);

     ($Bin,$Script) = $script =~ m,^(.*?)/+([^/]+)$,;

     # Resolve $script if it is a link
     while(1)
      {
       my $linktext = readlink($script);

       ($RealBin,$RealScript) = $script =~ m,^(.*?)/+([^/]+)$,;
       last unless defined $linktext;

       $script = ($linktext =~ m,^/,)
                  ? $linktext
                  : $RealBin . "/" . $linktext;
      }

     # Get absolute paths to directories
     $Bin     = abs_path($Bin)     if($Bin);
     $RealBin = abs_path($RealBin) if($RealBin);
    }
  }
}

1; # Keep require happy