laying the groundwork for adding/removing transport masters

libs/ardour/ardour/transport_master.h

@@ -155,7 +155,7 @@ class LIBARDOUR_API TransportMaster : public PBD::Stateful {
 	TransportMaster (SyncSource t, std::string const & name);
 	virtual ~TransportMaster();
 
-	static boost::shared_ptr<TransportMaster> factory (SyncSource, std::string const &);
+	static boost::shared_ptr<TransportMaster> factory (SyncSource, std::string const &, bool removeable);
 	static boost::shared_ptr<TransportMaster> factory (XMLNode const &);
 
 	virtual void pre_process (pframes_t nframes, samplepos_t now, boost::optional<samplepos_t>) = 0;
@@ -337,12 +337,20 @@ class LIBARDOUR_API TransportMaster : public PBD::Stateful {
 
 	void get_current (double&, samplepos_t&, samplepos_t);
 
+	/* this is set at construction, and not changeable later, so it is not
+	 * a property
+	 */
+
+	bool removeable () const { return _removeable; }
+	void set_removeable (bool yn) { _removeable = yn; }
+
   protected:
 	SyncSource      _type;
 	PBD::Property<std::string>   _name;
 	Session*        _session;
 	sampleoffset_t  _current_delta;
 	bool            _pending_collect;
+	bool            _removeable;
 	PBD::Property<TransportRequestType> _request_mask; /* lists transport requests still accepted when we're in control */
 	PBD::Property<bool> _locked;
 	PBD::Property<bool> _sclock_synced;

libs/ardour/ardour/transport_master_manager.h

@@ -41,7 +41,7 @@ class LIBARDOUR_API TransportMasterManager : public boost::noncopyable
 
 	typedef std::list<boost::shared_ptr<TransportMaster> > TransportMasters;
 
-	int add (SyncSource type, std::string const & name);
+	int add (SyncSource type, std::string const & name, bool removeable = true);
 	int remove (std::string const & name);
 	void clear ();
 

libs/ardour/transport_master.cc

@@ -68,6 +68,7 @@ TransportMaster::TransportMaster (SyncSource t, std::string const & name)
 	, _session (0)
 	, _current_delta (0)
 	, _pending_collect (true)
+	, _removeable (false)
 	, _request_mask (Properties::allowed_transport_requests, TransportRequestType (0))
 	, _locked (Properties::locked, false)
 	, _sclock_synced (Properties::sclock_synced, false)
@@ -285,6 +286,7 @@ TransportMaster::get_state ()
 {
 	XMLNode* node = new XMLNode (state_node_name);
 	node->set_property (X_("type"), _type);
+	node->set_property (X_("removeable"), _removeable);
 
 	add_properties (*node);
 
@@ -329,6 +331,7 @@ TransportMaster::factory (XMLNode const & node)
 
 	SyncSource type;
 	std::string name;
+	bool removeable;
 
 	if (!node.get_property (X_("type"), type)) {
 		return boost::shared_ptr<TransportMaster>();
@@ -338,28 +341,49 @@ TransportMaster::factory (XMLNode const & node)
 		return boost::shared_ptr<TransportMaster>();
 	}
 
-	return factory (type, name);
+	if (!node.get_property (X_("removeable"), removeable)) {
+		/* development versions of 6.0 didn't have this property for a
+		   while. Any TM listed in XML at that time was non-removeable
+		*/
+		removeable = false;
+	}
+
+	DEBUG_TRACE (DEBUG::Slave, string_compose ("xml-construct %1 name %2 removeable %3\n", enum_2_string (type), name, removeable));
+
+	return factory (type, name, removeable);
 }
 
 boost::shared_ptr<TransportMaster>
-TransportMaster::factory (SyncSource type, std::string const& name)
+TransportMaster::factory (SyncSource type, std::string const& name, bool removeable)
 {
 	/* XXX need to count existing sources of a given type */
 
+	boost::shared_ptr<TransportMaster> tm;
+
+	DEBUG_TRACE (DEBUG::Slave, string_compose ("factory-construct %1 name %2 removeable %3\n", enum_2_string (type), name, removeable));
+
 	switch (type) {
 	case MTC:
-		return boost::shared_ptr<TransportMaster> (new MTC_TransportMaster (sync_source_to_string (type)));
+		tm.reset (new MTC_TransportMaster (sync_source_to_string (type)));
+		break;
 	case LTC:
-		return boost::shared_ptr<TransportMaster> (new LTC_TransportMaster (sync_source_to_string (type)));
+		tm.reset (new LTC_TransportMaster (sync_source_to_string (type)));
+		break;
 	case MIDIClock:
-		return boost::shared_ptr<TransportMaster> (new MIDIClock_TransportMaster (sync_source_to_string (type)));
+		tm.reset (new MIDIClock_TransportMaster (sync_source_to_string (type)));
+		break;
 	case Engine:
-		return boost::shared_ptr<TransportMaster> (new Engine_TransportMaster (*AudioEngine::instance()));
+		tm.reset (new Engine_TransportMaster (*AudioEngine::instance()));
+		break;
 	default:
 		break;
 	}
 
-	return boost::shared_ptr<TransportMaster>();
+	if (tm) {
+		tm->set_removeable (removeable);
+	}
+
+	return tm;
 }
 
 boost::shared_ptr<Port>

libs/ardour/transport_master_manager.cc

@@ -57,10 +57,10 @@ TransportMasterManager::init ()
 		/* setup default transport masters. Most people will never need any
 		   others
 		*/
-		add (Engine, X_("JACK Transport"));
-		add (MTC, X_("MTC"));
-		add (LTC, X_("LTC"));
-		add (MIDIClock, X_("MIDI Clock"));
+		add (Engine, X_("JACK Transport"), false);
+		add (MTC, X_("MTC"), false);
+		add (LTC, X_("LTC"), false);
+		add (MIDIClock, X_("MIDI Clock"), false);
 	} catch (...) {
 		return -1;
 	}
@@ -306,14 +306,16 @@ TransportMasterManager::init_transport_master_dll (double speed, samplepos_t pos
 }
 
 int
-TransportMasterManager::add (SyncSource type, std::string const & name)
+TransportMasterManager::add (SyncSource type, std::string const & name, bool removeable)
 {
 	int ret = 0;
 	boost::shared_ptr<TransportMaster> tm;
 
+	DEBUG_TRACE (DEBUG::Slave, string_compose ("adding new transport master, type %1 name %2 removeable %3\n", enum_2_string (type), name, removeable));
+
 	{
 		Glib::Threads::RWLock::WriterLock lm (lock);
-		tm = TransportMaster::factory (type, name);
+		tm = TransportMaster::factory (type, name, removeable);
 		ret = add_locked (tm);
 	}
 
@@ -353,6 +355,9 @@ TransportMasterManager::remove (std::string const & name)
 
 		for (TransportMasters::iterator t = _transport_masters.begin(); t != _transport_masters.end(); ++t) {
 			if ((*t)->name() == name) {
+				if (!tm->removeable()) {
+					return -1;
+				}
 				tm = *t;
 				_transport_masters.erase (t);
 				ret = 0;