#!/usr/bin/perl

=head1 NAME

dh_update_autotools_config - Update autotools config files

=cut

use strict;
use warnings;
use Debian::Debhelper::Dh_Lib;

our $VERSION = DH_BUILTIN_VERSION;

=head1 SYNOPSIS

B<dh_update_autotools_config> [S<I<debhelper options>>]

=head1 DESCRIPTION

B<dh_update_autotools_config> replaces all occurrences of B<config.sub>
and B<config.guess> in the source tree by the up-to-date versions
found in the autotools-dev package.  The original files are backed up
and restored by B<dh_clean>.

=cut

init();

for my $basename (qw(config.guess config.sub)) {
	my $new_version = "/usr/share/misc/$basename";
	open(my $fd, '-|', 'find', '-mindepth', '1',
		 '(', '-type', 'd', '-name', '.*', '-prune', ')',
		 '-o', '-type', 'f', '-name', $basename, '-print')
		or error("Cannot run find -type f -name $basename: $!");
	while (my $filename = <$fd>) {
		chomp($filename);
		next if not is_autotools_config_file($filename);
		restore_file_on_clean($filename);
		doit('cp', '-f', $new_version, $filename);
	}
	close($fd);
}

sub is_autotools_config_file {
	my ($file) = @_;
	my ($is_autoconf_file);
	open(my $fd, '<', $file) or error("open $file for reading failed: $!");
	while (my $line = <$fd>) {
		chomp($line);
		# This is the test lintian uses.
		if ($line =~ m{^timestamp=['"]\d{4}-\d{2}-\d{2}['"]\s*$}) {
			$is_autoconf_file = 1;
			last;
		}
		$line =~ s/\s++$//;
		if ($line eq q{# Attempt to guess a canonical system name.}
			or $line =~ q{^# Configuration validation subroutine script}) {
			# Very old scripts do not have that timestamp line, but
			# they do have these headers (which even new files also
			# have).
			$is_autoconf_file = 1;
			last;
		}
		last if $. >= 10;
	}
	close($fd);
	return $is_autoconf_file;
}


=head1 SEE ALSO

L<debhelper(7)>

This program is a part of debhelper.

=head1 AUTHOR

Niels Thykier <niels@thykier.net>

=cut