prdiff

#!/usr/bin/perl

use strict;
use warnings;
use v5.030;
use OpenBSD::Paths;
use OpenBSD::Pledge;
use OpenBSD::Unveil;

unveil(OpenBSD::Paths->ftp, 'x') || die $!;
pledge(qw( proc exec )) || die $!;

sub usage
{
	say STDERR 'usage: prdiff owner/repo#pr';
	exit 1;
}

@ARGV == 1 || usage();

sub ftp_get
{
	my $url = shift;
	my @cmd = (OpenBSD::Paths->ftp, '-VMo-', $url);
	open(my $ftp_stdout, '-|', @cmd) or die "open `@cmd` failed: $!";
	my $is_diff;
	while (my $line = readline $ftp_stdout) {
		unless ($is_diff ||= $line =~ m/^diff /) {
			close($ftp_stdout);
			die "not a pull request";
		}
		print $line;
	}
	close($ftp_stdout);
}

sub print_pr
{
	my ($repo, $pull_num) = @_;
	my $url = 'https://patch-diff.githubusercontent.com' .
		"/raw/$repo/pull/$pull_num.diff";
	ftp_get($url);
}

my @args = $ARGV[0] =~ m{^([\w-]+/[\w-]+)#(\d+)$}; # owner/repo#pr
@args == 2 || usage();
print_pr(@args);