daemon: use ->can to check for IO::Socket::SSL

Doing a ref($obj) string comparison ties us to IO::Socket::SSL
(and OpenSSL) In the future, we may support GnuTLS or other TLS
implementations.  This was already done in the IMAP code.

1 files changed, 3 insertions, 3 deletions

diff --git a/lib/PublicInbox/NNTP.pm b/lib/PublicInbox/NNTP.pm
index bffd773c..be3bddc3 100644
--- a/lib/PublicInbox/NNTP.pm
+++ b/lib/PublicInbox/NNTP.pm
@@ -47,7 +47,7 @@ sub new ($$$) {
         my $self = fields::new($class);
         my $ev = EPOLLIN;
         my $wbuf;
-        if (ref($sock) eq 'IO::Socket::SSL' && !$sock->accept_SSL) {
+        if ($sock->can('accept_SSL') && !$sock->accept_SSL) {
                 return CORE::close($sock) if $! != EAGAIN;
                 $ev = PublicInbox::TLS::epollbit();
                 $wbuf = [ \&PublicInbox::DS::accept_tls_step, \&greet ];
@@ -97,7 +97,7 @@ sub process_line ($$) {
 sub cmd_capabilities ($;$) {
         my ($self, undef) = @_;
         my $res = $CAPABILITIES;
-        if (ref($self->{sock}) ne 'IO::Socket::SSL' &&
+        if (!$self->{sock}->can('accept_SSL') &&
                         $self->{nntpd}->{accept_tls}) {
                 $res .= "STARTTLS\r\n";
         }
@@ -896,7 +896,7 @@ sub cmd_starttls ($) {
         my ($self) = @_;
         my $sock = $self->{sock} or return;
         # RFC 4642 2.2.1
-        return r502 if (ref($sock) eq 'IO::Socket::SSL' || $self->compressed);
+        return r502 if ($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');