:
eval 'exec perl -wS $0 ${1+"$@"}'
    if 0;
#**************************************************************
#  
#  Licensed to the Apache Software Foundation (ASF) under one
#  or more contributor license agreements.  See the NOTICE file
#  distributed with this work for additional information
#  regarding copyright ownership.  The ASF licenses this file
#  to you under the Apache License, Version 2.0 (the
#  "License"); you may not use this file except in compliance
#  with the License.  You may obtain a copy of the License at
#  
#    http://www.apache.org/licenses/LICENSE-2.0
#  
#  Unless required by applicable law or agreed to in writing,
#  software distributed under the License is distributed on an
#  "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
#  KIND, either express or implied.  See the License for the
#  specific language governing permissions and limitations
#  under the License.
#  
#**************************************************************



use utf8;
use warnings;
use strict;

# command line arguments
my $oldpatchfile = shift;
my $newpatchfile = shift;
my $sortedfile = shift;

show_help() unless defined $oldpatchfile and defined $newpatchfile and defined $sortedfile;

my %oldpatchfile = parse_patch($oldpatchfile);
my %newpatchfile = parse_patch($newpatchfile);

open SORTEDPATCH, "> $sortedfile";

foreach my $file (sort (keys %newpatchfile)) {
	print SORTEDPATCH $file."\t";
	if (defined($oldpatchfile{$file})) {
		if ( (join '', @{$oldpatchfile{$file}{'data'}}) eq (join '', @{$newpatchfile{$file}{'data'}}) ) {
			# patch data for the file hasn't been modified, use the header from
			# the old patch, to reduce noise (keep the old timestamps)
			print SORTEDPATCH $oldpatchfile{$file}{'origtimestamp'}."\n";
			print SORTEDPATCH $oldpatchfile{$file}{'patchedfilename'}."\t";
			print SORTEDPATCH $oldpatchfile{$file}{'patchedtimestamp'}."\n";
			print SORTEDPATCH @{$oldpatchfile{$file}{'data'}};
			next;
		}
	}
	# either file wasn't patched before, or the patchset changed, so use the new
	# values for it..
	print SORTEDPATCH $newpatchfile{$file}{'origtimestamp'}."\n";
	print SORTEDPATCH $newpatchfile{$file}{'patchedfilename'}."\t";
	print SORTEDPATCH $newpatchfile{$file}{'patchedtimestamp'}."\n";
	print SORTEDPATCH @{$newpatchfile{$file}{'data'}};
}
close SORTEDPATCH;

###############
# Helper subs
###############
sub show_help {
	print "Usage: $0 oldpatch newpatch outputfilename\n";
	print "oldpatch and newpatch can be the very same file\n";
	print "will output a sanitized form of newpatch to outputfilename\n";
	print "if outputfilename is '-', the patch will be printed to stdout\n";
	print "sanitized means: It will avoid all unnecessary changes\n";
	exit 1;
}
sub parse_patch {
	my $patchfile = shift;
	my $patchtype;
	my $pfirst;
	my $psecond;

	my %hunks = ();
	my $origfilename;
	open PATCHFILE, "< $patchfile" or die "Cannot open file $patchfile $!";
	my @patchfile = <PATCHFILE>;
	close PATCHFILE;
	return %hunks if ( $#patchfile == -1 );
	if ( $patchfile[0] =~ /^---/ ) {
		$patchtype = "unified";
		$pfirst = '^--- [^\*]*$';
		$psecond = '^\+\+\+ [^\*]*$';
	} elsif ( $patchfile[0] =~ /^\*\*\*/ ) {
		$patchtype = "content";
		$pfirst = '^\*\*\* [^\*]*$';
		$psecond = '^--- .*\t.*$';
	} else {
		die "unknown patch format\n";
	}

	foreach (@patchfile) {
		if ( /$pfirst/ ) {
			my $timestamp;
			# extract the filename, to be able to compare the old
			# with the new file...
			($origfilename, $timestamp) = split(/\t/, $_, 2);
			chomp $timestamp;
			# ideally convert the timestamp to iso-format...
			$hunks{$origfilename}{'origtimestamp'} = $timestamp; 
			next;
		} elsif ( $_ =~ /$psecond/ ) {
			my ($filename, $timestamp) = split(/\t/, $_, 2);
			chomp $timestamp;
			# ideally convert the timestamp to iso-format...
			$hunks{$origfilename}{'patchedfilename'} = $filename;
			$hunks{$origfilename}{'patchedtimestamp'} = $timestamp;
			next;
		}
		push (@{$hunks{$origfilename}{'data'}}, $_);
		
	}
	return %hunks;
}