change API for GainControl, VCA and VCAManager

This allows sane state save/restore

libs/ardour/ardour/gain_control.h

@@ -20,7 +20,7 @@
 #define __ardour_gain_control_h__
 
 #include <string>
-#include <list>
+#include <set>
 
 #include <boost/shared_ptr.hpp>
 #include <glibmm/threads.h>
@@ -54,20 +54,28 @@ class LIBARDOUR_API GainControl : public AutomationControl {
 	double range_db;
 
 	gain_t get_master_gain () const;
-	void add_master (boost::shared_ptr<GainControl>);
-	void remove_master (boost::shared_ptr<GainControl>);
+	void add_master (boost::shared_ptr<VCA>);
+	void remove_master (boost::shared_ptr<VCA>);
 	void clear_masters ();
-	bool slaved_to (boost::shared_ptr<GainControl>) const;
+	bool slaved_to (boost::shared_ptr<VCA>) const;
+	std::vector<uint32_t> masters () const;
+
+	int set_state (XMLNode const&, int);
+	XMLNode& get_state();
 
   private:
 	void _set_value (double val, PBD::Controllable::GroupControlDisposition group_override);
 
 	mutable Glib::Threads::Mutex master_lock;
 
-	typedef std::list<boost::shared_ptr<GainControl> > Masters;
+	typedef std::set<boost::shared_ptr<GainControl> > Masters;
 	Masters _masters;
+	PBD::ScopedConnectionList masters_connections;
+	std::set<uint32_t> _masters_numbers;
+	std::string _masters_state_string ();
 
 	gain_t get_master_gain_locked () const;
+	void master_going_away (boost::weak_ptr<VCA>);
 };
 
 } /* namespace */

libs/ardour/ardour/vca.h

@@ -37,6 +37,7 @@ class LIBARDOUR_API VCA : public SessionHandleRef, public PBD::StatefulDestructi
   public:
 	VCA (Session& session, const std::string& name, uint32_t num);
 	VCA (Session& session, XMLNode const&, int version);
+	~VCA();
 
 	std::string name() const { return _name; }
 	uint32_t number () const { return _number; }
@@ -48,9 +49,6 @@ class LIBARDOUR_API VCA : public SessionHandleRef, public PBD::StatefulDestructi
 
 	boost::shared_ptr<GainControl> control() const { return _control; }
 
-	void add (boost::shared_ptr<Route>);
-	void remove (boost::shared_ptr<Route>);
-
 	XMLNode& get_state();
 	int set_state (XMLNode const&, int version);
 

libs/ardour/gain_control.cc

@@ -16,9 +16,14 @@
     675 Mass Ave, Cambridge, MA 02139, USA.
 */
 
+#include "pbd/convert.h"
+#include "pbd/strsplit.h"
+
 #include "ardour/dB.h"
 #include "ardour/gain_control.h"
 #include "ardour/session.h"
+#include "ardour/vca.h"
+#include "ardour/vca_manager.h"
 
 #include "i18n.h"
 
@@ -124,7 +129,7 @@ GainControl::get_master_gain_locked () const
 }
 
 void
-GainControl::add_master (boost::shared_ptr<GainControl> m)
+GainControl::add_master (boost::shared_ptr<VCA> vca)
 {
 	gain_t old_master_val;
 	gain_t new_master_val;
@@ -132,8 +137,17 @@ GainControl::add_master (boost::shared_ptr<GainControl> m)
 	{
 		Glib::Threads::Mutex::Lock lm (master_lock);
 		old_master_val = get_master_gain_locked ();
-		_masters.push_back (m);
+		_masters.insert (vca->control());
+		_masters_numbers.insert (vca->number());
 		new_master_val = get_master_gain_locked ();
+
+		/* note that we bind @param m as a weak_ptr<GainControl>, thus
+		   avoiding holding a reference to the control in the binding
+		   itself.
+		*/
+
+		vca->DropReferences.connect_same_thread (masters_connections, boost::bind (&GainControl::master_going_away, this, vca));
+
 	}
 
 	if (old_master_val != new_master_val) {
@@ -142,7 +156,16 @@ GainControl::add_master (boost::shared_ptr<GainControl> m)
 }
 
 void
-GainControl::remove_master (boost::shared_ptr<GainControl> m)
+GainControl::master_going_away (boost::weak_ptr<VCA> wv)
+{
+	boost::shared_ptr<VCA> v = wv.lock();
+	if (v) {
+		remove_master (v);
+	}
+}
+
+void
+GainControl::remove_master (boost::shared_ptr<VCA> vca)
 {
 	gain_t old_master_val;
 	gain_t new_master_val;
@@ -150,7 +173,8 @@ GainControl::remove_master (boost::shared_ptr<GainControl> m)
 	{
 		Glib::Threads::Mutex::Lock lm (master_lock);
 		old_master_val = get_master_gain_locked ();
-		_masters.remove (m);
+		_masters.erase (vca->control());
+		_masters_numbers.erase (vca->number());
 		new_master_val = get_master_gain_locked ();
 	}
 
@@ -169,6 +193,7 @@ GainControl::clear_masters ()
 		Glib::Threads::Mutex::Lock lm (master_lock);
 		old_master_val = get_master_gain_locked ();
 		_masters.clear ();
+		_masters_numbers.clear ();
 		new_master_val = get_master_gain_locked ();
 	}
 
@@ -178,8 +203,61 @@ GainControl::clear_masters ()
 }
 
 bool
-GainControl::slaved_to (boost::shared_ptr<GainControl> gc) const
+GainControl::slaved_to (boost::shared_ptr<VCA> vca) const
 {
 	Glib::Threads::Mutex::Lock lm (master_lock);
-	return find (_masters.begin(), _masters.end(), gc) != _masters.end();
+	return find (_masters.begin(), _masters.end(), vca->control()) != _masters.end();
+}
+
+XMLNode&
+GainControl::get_state ()
+{
+	XMLNode& node (AutomationControl::get_state());
+
+	/* store VCA master IDs */
+
+	string str;
+
+	{
+		Glib::Threads::Mutex::Lock lm (master_lock);
+		for (set<uint32_t>::const_iterator m = _masters_numbers.begin(); m != _masters_numbers.end(); ++m) {
+			if (!str.empty()) {
+				str += ',';
+			}
+			str += PBD::to_string (*m, std::dec);
+		}
+	}
+
+	if (!str.empty()) {
+		node.add_property (X_("masters"), str);
+	}
+
+	return node;
+}
+
+int
+GainControl::set_state (XMLNode const& node, int version)
+{
+	AutomationControl::set_state (node, version);
+
+	XMLProperty const* prop = node.property (X_("masters"));
+
+	/* XXXProblem here if we allow VCA's to be slaved to other VCA's .. we
+	 * have to load all VCAs first, then call ::set_state() so that
+	 * vca_by_number() will succeed.
+	 */
+
+	if (prop) {
+		vector<string> masters;
+		split (prop->value(), masters, ',');
+
+		for (vector<string>::const_iterator m = masters.begin(); m != masters.end(); ++m) {
+			boost::shared_ptr<VCA> vca = _session.vca_manager().vca_by_number (PBD::atoi (*m));
+			if (vca) {
+				add_master (vca);
+			}
+		}
+	}
+
+	return 0;
 }

libs/ardour/route.cc

@@ -5892,5 +5892,5 @@ Route::slaved_to (boost::shared_ptr<VCA> vca) const
 		return false;
 	}
 
-	return _gain_control->slaved_to (vca->control());
+	return _gain_control->slaved_to (vca);
 }

libs/ardour/vca.cc

@@ -66,6 +66,11 @@ VCA::VCA (Session& s, XMLNode const & node, int version)
 	set_state (node, version);
 }
 
+VCA::~VCA ()
+{
+	DropReferences (); /* emit signal */
+}
+
 void
 VCA::set_value (double val, Controllable::GroupControlDisposition gcd)
 {
@@ -78,19 +83,6 @@ VCA::get_value() const
 	return _control->get_value();
 }
 
-void
-VCA::add (boost::shared_ptr<Route> r)
-{
-	boost::dynamic_pointer_cast<GainControl>(r->gain_control())->add_master (_control);
-	std::cerr << name() << " now controlling " << r->name() << std::endl;
-}
-
-void
-VCA::remove (boost::shared_ptr<Route> r)
-{
-	r->gain_control()->remove_master (_control);
-}
-
 void
 VCA::set_name (string const& str)
 {

libs/ardour/vca_manager.cc

@@ -146,7 +146,6 @@ VCAManager::set_state (XMLNode const& node, int version)
 
 		for (XMLNodeList::const_iterator i = children.begin(); i != children.end(); ++i) {
 			if ((*i)->name() == VCA::xml_node_name) {
-				std::cerr << "Adding VCA from XML\n";
 				boost::shared_ptr<VCA> vca = boost::shared_ptr<VCA> (new VCA (_session, **i, version));
 				_vcas.push_back (vca);
 				vcal.push_back (vca);