2 files changed, 31 insertions, 35 deletions

diff --git a/libs/ardour/ardour/gain_control.h b/libs/ardour/ardour/gain_control.h
index 15be6d684f..f833163383 100644
--- a/libs/ardour/ardour/gain_control.h
+++ b/libs/ardour/ardour/gain_control.h
@@ -20,7 +20,7 @@
 #define __ardour_gain_control_h__
 
 #include <string>
-#include <set>
+#include <map>
 
 #include <boost/shared_ptr.hpp>
 #include <glibmm/threads.h>
@@ -70,34 +70,25 @@ class LIBARDOUR_API GainControl : public AutomationControl {
   private:
 	class MasterRecord {
           public:
-		MasterRecord (boost::shared_ptr<GainControl> gc, uint32_t n, double r)
+		MasterRecord (boost::shared_ptr<GainControl> gc, double r)
 			: _master (gc)
-			, _number (n)
 			, _ratio (r)
 		{}
 
 		boost::shared_ptr<GainControl> master() const { return _master; }
 		double ratio () const { return _ratio; }
-		uint32_t number() const { return _number; }
-
-		bool operator== (MasterRecord const& other) const {
-			return _number == other._number;
-		}
-
-		bool operator< (MasterRecord const& other) const {
-			return _number < other._number;
-		}
-
 		void reset_ratio (double r) { _ratio = r; }
 
-	  private:
-		const boost::shared_ptr<GainControl> _master;
-		const uint32_t _number;
+		PBD::ScopedConnection connection;
+
+         private:
+		boost::shared_ptr<GainControl> _master;
 		double _ratio;
+
 	};
 
 	mutable Glib::Threads::RWLock master_lock;
-	typedef std::set<MasterRecord> Masters;
+	typedef std::map<uint32_t,MasterRecord> Masters;
 	Masters _masters;
 	PBD::ScopedConnectionList masters_connections;
 	std::string _masters_state_string ();
@@ -105,7 +96,7 @@ class LIBARDOUR_API GainControl : public AutomationControl {
 	gain_t get_master_gain_locked () const;
 	void master_going_away (boost::weak_ptr<VCA>);
 	void recompute_masters_ratios (double val);
-	
+
 	void _set_value (double val, PBD::Controllable::GroupControlDisposition group_override);
 };
 
diff --git a/libs/ardour/gain_control.cc b/libs/ardour/gain_control.cc
index 124ce97d45..52752dcdda 100644
--- a/libs/ardour/gain_control.cc
+++ b/libs/ardour/gain_control.cc
@@ -56,7 +56,7 @@ GainControl::get_value () const
 
 	for (Masters::const_iterator mr = _masters.begin(); mr != _masters.end(); ++mr) {
 		/* get current master value, scale by our current ratio with that master */
-		g *= mr->master()->get_value () * mr->ratio();
+		g *= mr->second.master()->get_value () * mr->second.ratio();
 	}
 
 	return g;
@@ -155,7 +155,7 @@ GainControl::get_master_gain_locked () const
 
 	for (Masters::const_iterator mr = _masters.begin(); mr != _masters.end(); ++mr) {
 		/* get current master value, scale by our current ratio with that master */
-		g *= mr->master()->get_value () * mr->ratio();
+		g *= mr->second.master()->get_value () * mr->second.ratio();
 	}
 
 	return g;
@@ -173,18 +173,24 @@ GainControl::add_master (boost::shared_ptr<VCA> vca)
 
 		/* ratio will be recomputed below */
 
-		MasterRecord mr (vca->control(), vca->number(), 0.0);
+		res = _masters.insert (make_pair<uint32_t,MasterRecord> (vca->number(), MasterRecord (vca->control(), 0.0)));
 
-		res = _masters.insert (mr);
-		recompute_masters_ratios (old_master_val);
+		if (res.second) {
+			recompute_masters_ratios (old_master_val);
+
+			/* note that we bind @param m as a weak_ptr<GainControl>, thus
+			   avoiding holding a reference to the control in the binding
+			   itself.
+			*/
 
-		/* 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));
 
-		vca->DropReferences.connect_same_thread (masters_connections, boost::bind (&GainControl::master_going_away, this, vca));
-		vca->control()->Changed.connect_same_thread (masters_connections, boost::bind (&PBD::Signal0<void>::operator(), &Changed));
+			/* Store the connection inside the MasterRecord, so that when we destroy it, the connection is destroyed
+			   and we no longer hear about changes to the VCA.
+			*/
+
+			vca->control()->Changed.connect_same_thread (res.first->second.connection, boost::bind (&PBD::Signal0<void>::operator(), &Changed));
+		}
 	}
 
 	if (res.second) {
@@ -210,8 +216,7 @@ GainControl::remove_master (boost::shared_ptr<VCA> vca)
 	{
 		Glib::Threads::RWLock::WriterLock lm (master_lock);
 		old_master_val = get_master_gain_locked ();
-		MasterRecord mr (vca->control(), vca->number(), 0.0);
-		erased = _masters.erase (mr);
+		erased = _masters.erase (vca->number());
 		if (erased) {
 			recompute_masters_ratios (old_master_val);
 		}
@@ -278,13 +283,13 @@ GainControl::recompute_masters_ratios (double val)
 	double masters_total_gain_coefficient = 1.0;
 
 	for (Masters::iterator mr = _masters.begin(); mr != _masters.end(); ++mr) {
-		masters_total_gain_coefficient *= mr->master()->get_value();
+		masters_total_gain_coefficient *= mr->second.master()->get_value();
 	}
 
 	const double new_universal_ratio = pow ((val / masters_total_gain_coefficient), (1.0/nmasters));
 
 	for (Masters::iterator mr = _masters.begin(); mr != _masters.end(); ++mr) {
-		const_cast<MasterRecord*>(&(*mr))->reset_ratio (new_universal_ratio);
+		mr->second.reset_ratio (new_universal_ratio);
 	}
 }
 
@@ -292,7 +297,7 @@ bool
 GainControl::slaved_to (boost::shared_ptr<VCA> vca) const
 {
 	Glib::Threads::RWLock::ReaderLock lm (master_lock);
-	return find (_masters.begin(), _masters.end(), MasterRecord (vca->control(), vca->number(), 0.0)) != _masters.end();
+	return _masters.find (vca->number()) != _masters.end();
 }
 
 bool
@@ -317,7 +322,7 @@ GainControl::get_state ()
 			if (!str.empty()) {
 				str += ',';
 			}
-			str += PBD::to_string (mr->number(), std::dec);
+			str += PBD::to_string (mr->first, std::dec);
 		}
 	}