package blib;

=head1 NAME

blib - Use MakeMaker's uninstalled version of a package

=head1 SYNOPSIS

perl -Mblib script [args...]

perl -Mblib=dir script [args...]

=head1 DESCRIPTION

Looks for MakeMaker-like I<'blib'> directory structure starting in
I<dir> (or current directory) and working back up to five levels of '..'.

Intended for use on command line with B<-M> option as a way of testing
arbitrary scripts against an uninstalled version of a package.

However it is possible to :

use blib;
or
use blib '..';

etc. if you really must.

=head1 BUGS

Pollutes global name space for development only task.

=head1 AUTHOR

Nick Ing-Simmons nik@tiuk.ti.com

=cut

use Cwd;
use File::Spec;

use vars qw($VERSION $Verbose);
$VERSION = '1.06';
$Verbose = 0;

sub import
{
my $package = shift;
my $dir;
if ($^O eq "MSWin32" && -f "Win32.xs") {
# We don't use getcwd() on Windows because it will internally
# call Win32::GetCwd(), which will get the Win32 module loaded.
# That means that it would not be possible to run `make test`
# for the Win32 module because blib.pm would always load the
# installed version before @INC gets updated with the blib path.
chomp($dir = `cd`);
}
else {
$dir = getcwd;
}
if ($^O eq 'VMS') { ($dir = VMS::Filespec::unixify($dir)) =~ s-/\z--; }
if (@_)
{
$dir = shift;
$dir =~ s/blib\z//;
$dir =~ s,/+\z,,;
$dir = File::Spec->curdir unless ($dir);
die "$dir is not a directory\n" unless (-d $dir);
}

# detaint: if the user asked for blib, s/he presumably knew
# what s/he wanted
$dir = $1 if $dir =~ /^(.*)$/;

my $i = 5;
my($blib, $blib_lib, $blib_arch);
while ($i--)
{
$blib = File::Spec->catdir($dir, "blib");
$blib_lib = File::Spec->catdir($blib, "lib");
$blib_arch = File::Spec->catdir($blib, "arch");

if (-d $blib && -d $blib_arch && -d $blib_lib)
{
unshift(@INC,$blib_arch,$blib_lib);
warn "Using $blib\n" if $Verbose;
return;
}
$dir = File::Spec->catdir($dir, File::Spec->updir);
}
die "Cannot find blib even in $dir\n";
}

1;