[PATCH] ds: use MSG_MORE when wbuf is empty during long responses

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

HTTP::getline_pull and NNTP::long_step will both populate {wbuf}
manually to avoid recursion, so we need to account for an
empty-but-present {wbuf} while dispatching msg_more().
---
 lib/PublicInbox/DS.pm | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/lib/PublicInbox/DS.pm b/lib/PublicInbox/DS.pm
index 62aa3c2d..8f17f7fb 100644
--- a/lib/PublicInbox/DS.pm
+++ b/lib/PublicInbox/DS.pm
@@ -574,15 +574,18 @@ use constant MSG_MORE => ($^O eq 'linux') ? 0x8000 : 0;
 sub msg_more ($$) {
     my $self = $_[0];
     my $sock = $self->{sock} or return 1;
+    my $wbuf = $self->{wbuf};
 
-    if (MSG_MORE && !$self->{wbuf} && ref($sock) ne 'IO::Socket::SSL') {
+    if (MSG_MORE && (!defined($wbuf) || !scalar(@$wbuf)) &&
+		ref($sock) ne 'IO::Socket::SSL') {
         my $n = send($sock, $_[1], MSG_MORE);
         if (defined $n) {
             my $nlen = bytes::length($_[1]) - $n;
             return 1 if $nlen == 0; # all done!
             # queue up the unwritten substring:
             my $tmpio = tmpio($self, \($_[1]), $n) or return 0;
-            $self->{wbuf} = [ $tmpio ];
+            $self->{wbuf} //= $wbuf //= [];
+            push @$wbuf, $tmpio;
             epwait($sock, EPOLLOUT|EPOLLONESHOT);
             return 0;
         }