+ $winch_received = 0;
+ };
+
+ my $max_buffer_len = 256*1024;
+
+ my $drain_buffer = sub {
+ my ($fh, $buffer_ref) = @_;
+
+ my $len = length($$buffer_ref);
+ my $nr = syswrite($fh, $$buffer_ref);
+ if (!defined($nr)) {
+ return if $! == EINTR || $! == EAGAIN;
+ die "drain buffer - write error - $!\n";
+ }
+ return $nr if !$nr;
+ substr($$buffer_ref, 0, $nr, '');
+ $len = length($$buffer_ref);
+ $write_select->remove($fh) if !$len;
+ };
+
+ while (1) {
+ while(my ($readable, $writable) = IO::Select->select($read_select, $write_select, undef, 3)) {
+ $check_terminal_size->() if $winch_received;
+
+ foreach my $fh (@$writable) {
+ if ($fh == $output_fh) {
+ $drain_buffer->($output_fh, \$output_buffer);
+ $read_select->add($web_socket) if length($output_buffer) <= $max_buffer_len;
+ } elsif ($fh == $web_socket) {
+ $drain_buffer->($web_socket, \$websock_buffer);
+ }
+ }
+
+ foreach my $fh (@$readable) {
+
+ if ($fh == $web_socket) {
+ # Read from WebSocket
+
+ my $nr = $wb_socket_read_available_bytes->();
+ if (!defined($nr)) {
+ # wait
+ } elsif ($nr == 0) {
+ return; # EOF
+ } else {
+ my ($payload, $req_close) = $parse_web_socket_frame->(\$wsbuf);
+ if (defined($payload) && length($payload)) {
+ $output_buffer .= $payload;
+ $write_select->add($output_fh);
+ if (length($output_buffer) > $max_buffer_len) {
+ $read_select->remove($web_socket);
+ }
+ }
+ return if $req_close;
+ }
+
+ } elsif ($fh == $input_fh) {
+ # Read from STDIN
+
+ my $nr = sysread($input_fh, my $buff, 4096);
+ return if !$nr; # EOF or error
+
+ my $char = ord($buff);
+
+ # Handle escape sequences:
+ if ($in_escape_sequence) {
+ $in_escape_sequence = 0;
+ if ($char == 0x71) {
+ # (escape, 'q')
+ return;
+ } elsif ($char == $escape_char) {
+ # (escape, escape)
+ # Pass this one through as a single escapekey
+ } else {
+ # Unknown escape sequence
+ # We could generate a bell or something...
+ # but for now just skip it
+ next;
+ }
+ } elsif ($char == $escape_char) {
+ $in_escape_sequence = 1;
+ next;
+ }
+
+ # Pass the key through:
+ $websock_buffer .= $create_websockt_frame->("0:" . $nr . ":" . $buff);
+ $write_select->add($web_socket);
+ }
+ }
+ }
+ $check_terminal_size->() if $winch_received;
+
+ # got timeout
+ $websock_buffer .= $create_websockt_frame->("2"); # ping server to keep connection alive
+ $write_select->add($web_socket);