File mozilla-get-app-id of Package firefox6

#!/usr/bin/perl -w
use XML::Simple;

my $file = shift || die "Usage: $0 [install.rdf|somefile.xpi]\n";
my $xml;

if ($file =~ /\.xpi$/) {
	use Archive::Zip qw/:ERROR_CODES :CONSTANTS/;
	my $zip = Archive::Zip->new();
	if ( $zip->read($file) != AZ_OK ) {
		die "zip file read error\n";
	}
	my $data = $zip->contents("install.rdf");
	die "missing install.rdf in $file\n" unless $data;
	$xml = XMLin($data) || die "$!\n";
} elsif ($file =~ /install.rdf/) {
	$xml = XMLin($file) || die "$!\n";
} else {
	die "unsupported file format\n";
}

my $desc;
for my $tag (qw/RDF:Description Description/) {
	if (exists $xml->{$tag}) {
		if (ref $xml->{$tag} eq 'ARRAY') {
			$desc = $xml->{$tag};
		} else {
			$desc = [ $xml->{$tag} ];
		}
	}
}

my $uuid;
my $id;
for my $x (@$desc) {
	if ($x->{"em:id"} =~ /{[[:xdigit:]]+-/) {
		print STDERR "Warning: multiple uuids!\n" if defined $uuid;
		$uuid = $x->{"em:id"};
	} elsif ($x->{"em:id"} =~ /@/) {
		print STDERR "Warning: multiple ids!\n" if defined $id;
		$id = $x->{"em:id"};
	}
}

if (defined $id) {
	print "$id\n";
} elsif (defined $uuid) {
	print "$uuid\n";
} else {
	exit 1;
}