VCA: fix numbering scheme to allow contiguous numbers after removing the last VCA; remove unnecessary remote_control_id() method

2 files changed, 27 insertions, 18 deletions

diff --git a/libs/ardour/ardour/vca.h b/libs/ardour/ardour/vca.h
index 3364dd514b..65de6fb9ef 100644
--- a/libs/ardour/ardour/vca.h
+++ b/libs/ardour/ardour/vca.h
@@ -23,6 +23,8 @@
 #include <boost/shared_ptr.hpp>
 #include <boost/enable_shared_from_this.hpp>
 
+#include <glibmm/threads.h>
+
 #include "pbd/controllable.h"
 #include "pbd/statefuldestructible.h"
 
@@ -54,7 +56,6 @@ class LIBARDOUR_API VCA : public Stripable,
 	~VCA();
 
 	uint32_t number () const { return _number; }
-	uint32_t remote_control_id() const;
 
 	int init ();
 	XMLNode& get_state();
@@ -93,7 +94,7 @@ class LIBARDOUR_API VCA : public Stripable,
 	MonitorState monitoring_state() const;
 
 	static std::string default_name_template ();
-	static int next_vca_number ();
+	static uint32_t next_vca_number ();
 	static std::string xml_node_name;
 
 	/* used by Session to save/restore the atomic counter */
@@ -142,7 +143,7 @@ class LIBARDOUR_API VCA : public Stripable,
 	boost::shared_ptr<MonitorProcessor> monitor_control() const { return boost::shared_ptr<MonitorProcessor>(); }
 
   private:
-	uint32_t    _number;
+	uint32_t _number;
 
 	boost::shared_ptr<GainControl> _gain_control;
 	boost::shared_ptr<SoloControl> _solo_control;
@@ -151,7 +152,8 @@ class LIBARDOUR_API VCA : public Stripable,
 	// boost::shared_ptr<AutomationControl> _record_safe_control;
 	boost::shared_ptr<MonitorControl> _monitor_control;
 
-	static gint next_number;
+	static uint32_t next_number;
+	static Glib::Threads::Mutex number_lock;
 
 	void solo_target_going_away (boost::weak_ptr<Route>);
 	void mute_target_going_away (boost::weak_ptr<Route>);
diff --git a/libs/ardour/vca.cc b/libs/ardour/vca.cc
index 87853f7850..27ecec7910 100644
--- a/libs/ardour/vca.cc
+++ b/libs/ardour/vca.cc
@@ -34,7 +34,8 @@ using namespace ARDOUR;
 using namespace PBD;
 using std::string;
 
-gint VCA::next_number = 1;
+Glib::Threads::Mutex VCA::number_lock;
+uint32_t VCA::next_number = 1;
 string VCA::xml_node_name (X_("VCA"));
 
 string
@@ -43,25 +44,28 @@ VCA::default_name_template ()
 	return _("VCA %n");
 }
 
-int
+uint32_t
 VCA::next_vca_number ()
 {
-	/* recall that atomic_int_add() returns the value before the add. We
-	 * start at one, then next one will be two etc.
-	 */
-	return g_atomic_int_add (&next_number, 1);
+	/* we could use atomic inc here, but elsewhere we need more complete
+	   mutex semantics, so we have to do it here also.
+	*/
+	Glib::Threads::Mutex::Lock lm (number_lock);
+	return next_number++;
 }
 
 void
 VCA::set_next_vca_number (uint32_t n)
 {
-	g_atomic_int_set (&next_number, n);
+	Glib::Threads::Mutex::Lock lm (number_lock);
+	next_number = n;
 }
 
 uint32_t
 VCA::get_next_vca_number ()
 {
-	return g_atomic_int_get (&next_number);
+	Glib::Threads::Mutex::Lock lm (number_lock);
+	return next_number;
 }
 
 VCA::VCA (Session& s,  uint32_t num, const string& name)
@@ -91,12 +95,15 @@ VCA::init ()
 VCA::~VCA ()
 {
 	DEBUG_TRACE (DEBUG::Destruction, string_compose ("delete VCA %1\n", number()));
-}
-
-uint32_t
-VCA::remote_control_id () const
-{
-	return 9999999 + _number;
+	{
+		Glib::Threads::Mutex::Lock lm (number_lock);
+		if (_number == next_number - 1) {
+			/* this was the "last" VCA added, so rewind the next number so
+			 * that future VCAs get numbered as intended
+			 */
+			next_number--;
+		}
+	}
 }
 
 XMLNode&