nntp: do not drain rbuf if there is a command pending

Some clients pipeline requests aggressively (enough to match
LINE_MAX) and we should not read from the client socket until we
know there's no pending command in our read buffer.

Reported-and-tested-by: Sergey Organov <sorganov@gmail.com>

1 files changed, 5 insertions, 3 deletions

diff --git a/lib/PublicInbox/NNTP.pm b/lib/PublicInbox/NNTP.pm
index 1e564634..267fe4b9 100644
--- a/lib/PublicInbox/NNTP.pm
+++ b/lib/PublicInbox/NNTP.pm
@@ -949,10 +949,12 @@ sub event_write {
 sub event_read {
         my ($self) = @_;
         use constant LINE_MAX => 512; # RFC 977 section 2.3
-        my $r = 1;
 
-        my $buf = $self->read(LINE_MAX) or return $self->close;
-        $self->{rbuf} .= $$buf;
+        if (index($self->{rbuf}, "\n") < 0) {
+                my $buf = $self->read(LINE_MAX) or return $self->close;
+                $self->{rbuf} .= $$buf;
+        }
+        my $r = 1;
         while ($r > 0 && $self->{rbuf} =~ s/\A\s*([^\r\n]+)\r?\n//) {
                 my $line = $1;
                 return $self->close if $line =~ /[[:cntrl:]]/s;