#!/usr/bin/perl -w

=head1 NAME

dh_strip_nondeterminism - strip uninteresting, nondeterministic information from files

=cut

use strict;
use warnings;
use B;
use File::Find;
use Debian::Debhelper::Dh_Lib;
use File::StripNondeterminism;

=head1 SYNOPSIS

B<dh_strip_nondeterminism> [S<I<debhelper options>>] [B<-X>I<item>]

=head1 DESCRIPTION

B<dh_strip_nondeterminism> is a debhelper program that is responsible
for stripping uninteresting, nondeterministic information, such as
timestamps, from compiled files so that the build is reproducible.

This program examines your package build directories and works out what
to strip on its own. It uses L<file(1)> and filenames to figure out what
files should have nondeterminism stripped from them.  In general it
seems to make very good guesses, and will do the right thing in almost
all cases.

=head1 OPTIONS

=over 4

=item B<-X>I<item>, B<--exclude=>I<item>

Exclude files that contain I<item> anywhere in their filename from being
stripped. You may use this option multiple times to build up a list of
things to exclude.

=back

=cut

init();

my (@nondeterministic_files, %seen);

sub testfile {
	return if -l $_ or -d $_; # Skip directories and symlinks always.

	# See if we were asked to exclude this file.
	# Note that we have to test on the full filename, including directory.
	my $fn="$File::Find::dir/$_";
	foreach my $f (@{$dh{EXCLUDE}}) {
		return if ($fn=~m/\Q$f\E/);
	}

	# Deduplicate hardlinks to avoid issues under parallelism
	my ($dev, $inode, undef, $nlink) = stat($_);
	return if defined $nlink && $nlink > 1 && $seen{"$inode.$dev"};
	$seen{"$inode.$dev"} = 1;

	my $normalizer = File::StripNondeterminism::get_normalizer_for_file($_);
	if ($normalizer) {
		push @nondeterministic_files, [$fn, $normalizer];
	}
}

sub handler_name {
	eval {
		my $obj = B::svref_2object(shift());
		return $obj->GV->STASH->NAME;
	} || "unknown handler";
}

File::StripNondeterminism::init();

foreach my $package (@{$dh{DOPACKAGES}}) {
	my $tmp=tmpdir($package);

	next if not -d $tmp;

	@nondeterministic_files=();
	find(\&testfile,$tmp);
	next unless @nondeterministic_files;

	$File::StripNondeterminism::canonical_time = get_source_date_epoch();

	verbose_print("Using $File::StripNondeterminism::canonical_time as canonical time");

	on_items_in_parallel(\@nondeterministic_files, sub {
		foreach (@_) {
			my ($path, $normalize) = @$_;
			verbose_print("Normalizing $path using " . handler_name($normalize));
			eval { $normalize->($path) or nonquiet_print("Normalized $path"); 1; }
			  or error("$path: $@");
		}
	});
}

=head1 SEE ALSO

L<debhelper(7)>

This program is a part of debhelper.

=head1 AUTHORS

Andrew Ayer <agwa@andrewayer.name>
Chris Lamb <lamby@debian.org>

=cut