Prevent deletion of last port using the PortMatrix.

diff --git a/gtk2_ardour/port_matrix.cc b/gtk2_ardour/port_matrix.cc
index 34e0f68c7ed857e5bbcce15fb4a7b87bddc301de..11a76dddc6768abfb2c1475a95bec57954d0d262 100644 (file)
--- a/gtk2_ardour/port_matrix.cc
+++ b/gtk2_ardour/port_matrix.cc
@@ -747,23 +747,31 @@ PortMatrix::can_remove_channels (boost::shared_ptr<Bundle> b) const
 void
 PortMatrix::remove_channel (ARDOUR::BundleChannel b)
 {
+       std::string errmsg;
        boost::shared_ptr<IO> io = io_from_bundle (b.bundle);
+       boost::shared_ptr<Port> p = io->nth (b.channel);
 
-       if (io) {
-               boost::shared_ptr<Port> p = io->nth (b.channel);
-               if (p) {
-                       int const r = io->remove_port (p, this);
-                       if (r == -1) {
-                               ArdourDialog d (_("Port removal not allowed"));
-                               Label l (_("This port cannot be removed.\nEither the first plugin in the track or buss cannot accept\nthe new number of inputs or the last plugin has more outputs."));
-                               d.get_vbox()->pack_start (l);
-                               d.add_button (Stock::OK, RESPONSE_ACCEPT);
-                               d.set_modal (true);
-                               d.show_all ();
-                               d.run ();
-                       }
+       if (!io || !p) {
+               return;
+       }
+
+       if (io->n_ports ().n_total () == 1) {
+               errmsg = _("The last port cannot be removed");
+       } else {
+               if (-1 == io->remove_port (p, this)) {
+                       errmsg = _("This port cannot be removed.\nEither the first plugin in the track or buss cannot accept\nthe new number of inputs or the last plugin has more outputs.");
                }
        }
+
+       if (!errmsg.empty ()) {
+               ArdourDialog d (_("Port removal not allowed"));
+               Label l (errmsg);
+               d.get_vbox()->pack_start (l);
+               d.add_button (Stock::OK, RESPONSE_ACCEPT);
+               d.set_modal (true);
+               d.show_all ();
+               d.run ();
+       }
 }
 
 void