#!/usr/bin/perl

#############################################################################

# Copyright (c) 2015 Micro Focus

# All Rights Reserved.

#

# This program is free software; you can redistribute it and/or

# modify it under the terms of version 2 of the GNU General Public License as

# published by the Free Software Foundation.

#

# 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, contact Novell, Inc.

#

# To contact Novell about this file by physical or electronic mail,

# you may find current contact information at www.novell.com

#############################################################################

# Check that the a patch is in the format produced by scripts/refresh_patch.sh

use strict;

use warnings;

my $errors = 0;

my $git_renames = 0;

my %reported;

our $file;

sub err {

	return if ($reported{"$file:$_[0]"}++);

	print STDERR "$file:$.: error: @_\n";

	$errors = 1;

}

sub check_filename {

	my $filename = shift;

	if ($filename !~ m:^(/dev/null\b|[ab]/):) {

		err("Patch not in -p ab format");

	}

	if ($filename =~ /\s\S/) {

		err("Timestamp after filename");

	}

	if ($filename =~ /\/\//) {

		err("Double slash in filename");

	}

}

sub do_patch {

	my $fh = shift;

	my $fn = shift;

	my ($in_payload, $in_hunk, $maybe_eof, $last_noncontext);

	my $xen_prefix = "patches.xen/";

	my $is_xen = $xen_prefix eq substr($fn,0,length($xen_prefix));

	my @lines = <$fh>;

	chomp(@lines);

	for (my $i = 1; $i < scalar(@lines); $i++) {

		my $cur = $lines[$i];

		$. = $i + 1;

		if ($cur =~ /^similarity index \d+%/ &&

					$lines[$i-1] =~ /^diff --git/) {

			$in_payload = 1;

			$in_hunk = 0;

			$maybe_eof = 0;

			err("git diff -M patches fail with sequences-patch.sh --fast");

			$git_renames = 1;

		}

		if ($cur =~ /^\+\+\+ / && $lines[$i-1] =~ /^--- /) {

			$in_payload = 1;

			$in_hunk = 0;

			$maybe_eof = 0;

			(my $new = $cur) =~ s/^\+\+\+ //;

			(my $old = $lines[$i-1]) =~ s/^--- //;

			if (!$is_xen) { check_filename($new); }

			if (!$is_xen) { check_filename($old); }

			if (!$is_xen && $i > 2 && $lines[$i-2] =~ /^={20}/ &&

						$lines[$i-3] =~ /^Index: /) {

				err("Superfluous Index: line in patch");

			}

			next;

		}

		next unless $in_payload;

		if ($cur =~ /^(diff |Index: |--- |\\ No newline at end of file)/) {

			$in_hunk = 0;

			$maybe_eof = 0;

			next;

		} elsif ($cur =~ /^@@ /) {

			$in_hunk = 1;

			$last_noncontext = $i;

			$maybe_eof = 0;

			next;

		}

		next unless $in_hunk;

		# "-- " can be used as signature delimiter and is sometimes

		# written as "--"

		if ($cur =~ /^-- ?$/) {

			$maybe_eof = 1;

			next;

		}

		if ($cur =~ /^[-+]/) {

			$last_noncontext = $i;

			next;

		}

		# Blank lines seem to be OK for git am

		if ($cur =~ /^$|^ /) {

			next;

		}

		# Try to ignore junk at the end of patch files

		if ($i - $last_noncontext <= 3 && !$maybe_eof) {

			err("Malformed patch (missing leading space in context line?)");

		}

	}

}

if (!@ARGV) {

	die "Usage: $0 <patch>...\n";

}

if ($ARGV[0] eq "--stdin") {

	shift;

	$file = "<stdin>";

	if (scalar(@ARGV)) {

		$file = $ARGV[0];

	}

	open(my $fh, '-');

	do_patch($fh, $file);

	close($fh);

} else {

	for $file (@ARGV) {

		open(my $fh, '<', $file) or die "$file: $!\n";

		do_patch($fh, $file);

		close($fh);

	}

}

if ($errors) {

	printf STDERR ("Please refresh the patch%s using scripts/refresh_patch.sh\n", (scalar(@ARGV) > 1 ? "es" : ""));

	if ($git_renames) {

		print STDERR "Use --no-renames when generating patches from git\n";

	}

	exit(1);

}

exit(0);