#! /usr/bin/perl
#
# Copyright 2003 by Stefan Hornburg (Racke) <racke@linuxia.de>
#
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation; either version 2 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public
# License along with this program; if not, write to the Free
# Software Foundation, Inc., 59 Temple Place, Suite 330, Boston,
# MA  02111-1307  USA.

use strict;
use warnings;

use Cwd;
use File::Find;

my (@files, @dirs, %fmap);
my $topdir = cwd();
my $command = shift || '';

if ($command eq 'cleanse') {
	# read list of files to be preserved from stdin
	while (<>) {
		chomp();
		$fmap{$_} = 1;
	}
	# call routine to remove files and symlinks, collects obsolete dirs too
	find (\&cleanse_files, $topdir);
	# the obsolete dirs are empty too, remove them
	for (@dirs) {
		next unless -d $_;
		rmdir ($_)
			|| die "Couldn't remove directory $_: $!\n";
	}
} else {
	# collect existing files and write them to stdou
	find (\&collect_files, $topdir);
	print join("\n", @files);
}

sub collect_files {
	return if -d $_ && $_ eq '.';
	my $f = substr($File::Find::name, length($topdir) + 1);
	push (@files, $f);
}

sub cleanse_files {
	return if -d $_ && $_ eq '.';
	my $f = substr($File::Find::name, length($topdir) + 1);
	unless (exists ($fmap{$f})) {
		if (-f $_ || -l $_) {
			unlink ($_)
				|| die "couldn't remove file $File::Find::name: $!\n";
		}
		if (-d $_) {
			push (@dirs, $f);
		}
	}
}