From fbfd63996ddfc9a23b8a1e0f8756e378f2e196ba Mon Sep 17 00:00:00 2001
From: Jonathan Corbet <corbet@lwn.net>
Date: Sat, 13 Oct 2018 15:42:21 -0600
Subject: Add Xrefs to over/xover lines

Putting the Xref field into xover lines allows newsreaders to mark
cross-posted messages read when catching up a group.  That, in turn,
massively improves the life of crazy people who try to follow dozens of
kernel lists, where emails are often heavily cross-posted.
---
 lib/PublicInbox/NNTP.pm | 13 +++++++------
 t/nntpd.t               | 11 ++++++++---
 2 files changed, 15 insertions(+), 9 deletions(-)

diff --git a/lib/PublicInbox/NNTP.pm b/lib/PublicInbox/NNTP.pm
index cbd4ecf1..022bb809 100644
--- a/lib/PublicInbox/NNTP.pm
+++ b/lib/PublicInbox/NNTP.pm
@@ -28,7 +28,7 @@ use constant {
 
 sub now () { clock_gettime(CLOCK_MONOTONIC) };
 
-my @OVERVIEW = qw(Subject From Date Message-ID References);
+my @OVERVIEW = qw(Subject From Date Message-ID References Xref);
 my $OVERVIEW_FMT = join(":\r\n", @OVERVIEW, qw(Bytes Lines)) . ":\r\n";
 my $LIST_HEADERS = join("\r\n", @OVERVIEW,
 			qw(:bytes :lines Xref To Cc)) . "\r\n";
@@ -812,8 +812,8 @@ sub cmd_xrover ($;$) {
 	});
 }
 
-sub over_line ($$) {
-	my ($num, $smsg) = @_;
+sub over_line ($$$$) {
+	my ($self, $ng, $num, $smsg) = @_;
 	# n.b. field access and procedural calls can be
 	# 10%-15% faster than OO method calls:
 	my $s = join("\t", $num,
@@ -823,7 +823,8 @@ sub over_line ($$) {
 		"<$smsg->{mid}>",
 		$smsg->{references},
 		$smsg->{bytes},
-		$smsg->{lines});
+		$smsg->{lines},
+		"Xref: " . xref($self, $ng, $num, $smsg->{mid}));
 	utf8::encode($s);
 	$s
 }
@@ -839,7 +840,7 @@ sub cmd_over ($;$) {
 		# Only set article number column if it's the current group
 		my $self_ng = $self->{ng};
 		$n = 0 if (!$self_ng || $self_ng ne $ng);
-		more($self, over_line($n, $smsg));
+		more($self, over_line($self, $ng, $n, $smsg));
 		'.';
 	} else {
 		cmd_xover($self, $range);
@@ -861,7 +862,7 @@ sub cmd_xover ($;$) {
 
 		# OVERVIEW.FMT
 		more($self, join("\r\n", map {
-			over_line($_->{num}, $_);
+			over_line($self, $self->{ng}, $_->{num}, $_);
 			} @$msgs));
 		$cur = $msgs->[-1]->{num} + 1;
 	});
diff --git a/t/nntpd.t b/t/nntpd.t
index f8599080..9c1d0762 100644
--- a/t/nntpd.t
+++ b/t/nntpd.t
@@ -196,7 +196,9 @@ EOF
 			'<nntp@example.com>',
 			'<reftabsqueezed>',
 			$len,
-			'1' ] }, "XOVER range works");
+			'1',
+			'Xref: '. hostname . ' test-nntpd:1'] },
+		"XOVER range works");
 
 	is_deeply($n->xover('1'), {
 		'1' => ["Testing for El\xc3\xa9anor",
@@ -205,7 +207,9 @@ EOF
 			'<nntp@example.com>',
 			'<reftabsqueezed>',
 			$len,
-			'1' ] }, "XOVER by article works");
+			'1',
+			'Xref: '. hostname . ' test-nntpd:1'] },
+		"XOVER by article works");
 
 	is_deeply($n->head(1), $n->head('<nntp@example.com>'), 'HEAD OK');
 	is_deeply($n->body(1), $n->body('<nntp@example.com>'), 'BODY OK');
@@ -225,7 +229,8 @@ EOF
 		is($r[1], "0\tTesting for El\xc3\xa9anor\t" .
 			"El\xc3\xa9anor <me\@example.com>\t" .
 			"Thu, 01 Jan 1970 06:06:06 +0000\t" .
-			"$mid\t<reftabsqueezed>\t$len\t1",
+			"$mid\t<reftabsqueezed>\t$len\t1" .
+			"\tXref: " . hostname . " test-nntpd:0",
 			'OVER by Message-ID works');
 		is($r[2], '.', 'correctly terminated response');
 	}
-- 
cgit v1.2.3-24-ge0c7