[PATCH 02/11] nntp: start adding CRLF to responses natively

[Eric Wong <e@80x24.org>]

With IMAP and POP3, I've started to embed CRLF into constant
response codes to avoid triggering CoW and extra memory traffic
in Perl.

The end goal is to enable more code sharing between IMAP, NNTP,
and POP3 inside one -netd process.
---
 lib/PublicInbox/NNTP.pm | 35 ++++++++++++++---------------------
 1 file changed, 14 insertions(+), 21 deletions(-)

diff --git a/lib/PublicInbox/NNTP.pm b/lib/PublicInbox/NNTP.pm
index 3d304c52..1f9058ca 100644
--- a/lib/PublicInbox/NNTP.pm
+++ b/lib/PublicInbox/NNTP.pm
@@ -24,9 +24,9 @@ use constant {
 	LINE_MAX => 512, # RFC 977 section 2.3
 	r501 => '501 command syntax error',
 	r502 => '502 Command unavailable',
-	r221 => '221 Header follows',
+	r221 => "221 Header follows\r\n",
 	r224 => '224 Overview information follows (multi-line)',
-	r225 =>	'225 Headers follow (multi-line)',
+	r225 =>	"225 Headers follow (multi-line)\r\n",
 	r430 => '430 No article with that message-id',
 };
 use PublicInbox::Syscall qw(EPOLLIN EPOLLONESHOT);
@@ -82,8 +82,8 @@ sub process_line ($$) {
 	my ($self, $l) = @_;
 	my ($req, @args) = split(/[ \t]+/, $l);
 	return 1 unless defined($req); # skip blank line
-	$req = $self->can('cmd_'.lc($req));
-	return res($self, '500 command not recognized') unless $req;
+	$req = $self->can('cmd_'.lc($req)) //
+		return $self->write(\"500 command not recognized\r\n");
 	return res($self, r501) unless args_ok($req, scalar @args);
 
 	my $res = eval { $req->($self, @args) };
@@ -403,7 +403,7 @@ sub cmd_post ($) {
 
 sub cmd_quit ($) {
 	my ($self) = @_;
-	res($self, '205 closing connection - goodbye!');
+	$self->write(\"205 closing connection - goodbye!\r\n");
 	$self->shutdn;
 	undef;
 }
@@ -663,7 +663,7 @@ sub long_step {
 		$self->requeue if $new_size == 1;
 	} else { # all done!
 		delete $self->{long_cb};
-		res($self, '.');
+		$self->write(\".\r\n");
 		my $elapsed = now() - $t0;
 		my $fd = fileno($self->{sock});
 		out($self, " deferred[$fd] done - %0.6f", $elapsed);
@@ -703,7 +703,7 @@ sub hdr_message_id ($$$) { # optimize XHDR Message-ID [range] for slrnpull.
 		$range = $self->{article} unless defined $range;
 		my $r = get_range($self, $range);
 		return $r unless ref $r;
-		more($self, $xhdr ? r221 : r225);
+		$self->msg_more($xhdr ? r221 : r225);
 		long_response($self, \&hdr_msgid_range_i, @$r);
 	}
 }
@@ -775,7 +775,7 @@ sub hdr_xref ($$$) { # optimize XHDR Xref [range] for rtin
 		$range = $self->{article} unless defined $range;
 		my $r = get_range($self, $range);
 		return $r unless ref $r;
-		more($self, $xhdr ? r221 : r225);
+		$self->msg_more($xhdr ? r221 : r225);
 		long_response($self, \&xref_range_i, @$r);
 	}
 }
@@ -819,7 +819,7 @@ sub hdr_smsg ($$$$) {
 		$range = $self->{article} unless defined $range;
 		my $r = get_range($self, $range);
 		return $r unless ref $r;
-		more($self, $xhdr ? r221 : r225);
+		$self->msg_more($xhdr ? r221 : r225);
 		long_response($self, \&smsg_range_i, @$r, $field);
 	}
 }
@@ -837,7 +837,7 @@ sub do_hdr ($$$;$) {
 	} elsif ($sub =~ /\A:(bytes|lines)\z/) {
 		hdr_smsg($self, $xhdr, $1, $range);
 	} else {
-		$xhdr ? (r221 . "\r\n.") : "503 HDR not permitted on $header";
+		$xhdr ? (r221 . '.') : "503 HDR not permitted on $header";
 	}
 }
 
@@ -867,16 +867,9 @@ sub hdr_mid_prefix ($$$$$) {
 
 sub hdr_mid_response ($$$$$$) {
 	my ($self, $xhdr, $ibx, $n, $mid, $v) = @_;
-	my $res = '';
-	if ($xhdr) {
-		$res .= r221 . "\r\n";
-		$res .= "$mid $v\r\n";
-	} else {
-		$res .= r225 . "\r\n";
-		my $pfx = hdr_mid_prefix($self, $xhdr, $ibx, $n, $mid);
-		$res .= "$pfx $v\r\n";
-	}
-	res($self, $res .= '.');
+	$self->write(($xhdr ? r221.$mid :
+		   r225.hdr_mid_prefix($self, $xhdr, $ibx, $n, $mid)) .
+		" $v\r\n.\r\n");
 	undef;
 }
 
@@ -972,7 +965,7 @@ sub cmd_starttls ($) {
 	return r502 if ($sock->can('accept_SSL') || $self->compressed);
 	my $opt = $self->{nntpd}->{accept_tls} or
 		return '580 can not initiate TLS negotiation';
-	res($self, '382 Continue with TLS negotiation');
+	$self->write(\"382 Continue with TLS negotiation\r\n");
 	$self->{sock} = IO::Socket::SSL->start_SSL($sock, %$opt);
 	$self->requeue if PublicInbox::DS::accept_tls_step($self);
 	undef;