From c660703f95a269a7f312e84564345f8961cb7e75 Mon Sep 17 00:00:00 2001
From: Paul Davis <paul@linuxaudiosystems.com>
Date: Tue, 8 Mar 2016 23:29:17 -0500
Subject: redesign control slave/master system, move code from GainControl to
 AutomationControl

---
 libs/ardour/automation_control.cc | 129 +++++++++++++++++++++++++++++++++++++-
 1 file changed, 128 insertions(+), 1 deletion(-)

(limited to 'libs/ardour/automation_control.cc')

diff --git a/libs/ardour/automation_control.cc b/libs/ardour/automation_control.cc
index 3629345d94..4317a18788 100644
--- a/libs/ardour/automation_control.cc
+++ b/libs/ardour/automation_control.cc
@@ -56,6 +56,7 @@ AutomationControl::AutomationControl(ARDOUR::Session&                          s
 
 AutomationControl::~AutomationControl ()
 {
+	DropReferences (); /* EMIT SIGNAL */
 }
 
 bool
@@ -73,9 +74,36 @@ double
 AutomationControl::get_value() const
 {
 	bool from_list = _list && ((AutomationList*)_list.get())->automation_playback();
-	return Control::get_double (from_list, _session.transport_frame());
+
+	if (!from_list) {
+		Glib::Threads::RWLock::ReaderLock lm (master_lock);
+		return get_value_locked ();
+	} else {
+		return Control::get_double (from_list, _session.transport_frame());
+	}
+}
+
+double
+AutomationControl::get_value_locked() const
+{
+	/* read or write masters lock must be held */
+
+	if (_masters.empty()) {
+		return Control::get_double (false, _session.transport_frame());
+	}
+
+	gain_t v = 1.0;
+
+	for (Masters::const_iterator mr = _masters.begin(); mr != _masters.end(); ++mr) {
+		/* get current master value, scale by our current ratio with that master */
+		v *= mr->second.master()->get_value () * mr->second.ratio();
+	}
+
+	return min (_desc.upper, v);
 }
 
+
+
 /** Set the value and do the right thing based on automation state
  *  (e.g. record if necessary, etc.)
  *  @param value `user' value
@@ -232,3 +260,102 @@ AutomationControl::interface_to_internal (double val) const
 }
 
 
+void
+AutomationControl::add_master (boost::shared_ptr<AutomationControl> m)
+{
+	double current_value;
+	std::pair<Masters::iterator,bool> res;
+
+	{
+		Glib::Threads::RWLock::WriterLock lm (master_lock);
+		current_value = get_value_locked ();
+
+		/* ratio will be recomputed below */
+
+		res = _masters.insert (make_pair<PBD::ID,MasterRecord> (m->id(), MasterRecord (m, 1.0)));
+
+		if (res.second) {
+
+			recompute_masters_ratios (current_value);
+
+			/* note that we bind @param m as a weak_ptr<AutomationControl>, thus
+			   avoiding holding a reference to the control in the binding
+			   itself.
+			*/
+
+			m->DropReferences.connect_same_thread (masters_connections, boost::bind (&AutomationControl::master_going_away, this, m));
+
+			/* 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 AutomationControl.
+			*/
+
+			m->Changed.connect_same_thread (res.first->second.connection, boost::bind (&PBD::Signal0<void>::operator(), &Changed));
+		}
+	}
+
+	if (res.second) {
+		MasterStatusChange (); /* EMIT SIGNAL */
+	}
+}
+
+void
+AutomationControl::master_going_away (boost::weak_ptr<AutomationControl> wm)
+{
+	boost::shared_ptr<AutomationControl> m = wm.lock();
+	if (m) {
+		remove_master (m);
+	}
+}
+
+void
+AutomationControl::remove_master (boost::shared_ptr<AutomationControl> m)
+{
+	double current_value;
+	Masters::size_type erased = 0;
+
+	{
+		Glib::Threads::RWLock::WriterLock lm (master_lock);
+		current_value = get_value_locked ();
+		erased = _masters.erase (m->id());
+		if (erased) {
+			recompute_masters_ratios (current_value);
+		}
+	}
+
+	if (erased) {
+		MasterStatusChange (); /* EMIT SIGNAL */
+	}
+}
+
+void
+AutomationControl::clear_masters ()
+{
+	bool had_masters = false;
+
+	{
+		Glib::Threads::RWLock::WriterLock lm (master_lock);
+		if (!_masters.empty()) {
+			had_masters = true;
+		}
+		_masters.clear ();
+	}
+
+	if (had_masters) {
+		MasterStatusChange (); /* EMIT SIGNAL */
+	}
+}
+
+bool
+AutomationControl::slaved_to (boost::shared_ptr<AutomationControl> m) const
+{
+	Glib::Threads::RWLock::ReaderLock lm (master_lock);
+	return _masters.find (m->id()) != _masters.end();
+}
+
+bool
+AutomationControl::slaved () const
+{
+	Glib::Threads::RWLock::ReaderLock lm (master_lock);
+	return !_masters.empty();
+}
+
-- 
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