From a0810ed608cfa50a9f20269cf830fc1afa22da76 Mon Sep 17 00:00:00 2001
From: Robin Gareus <robin@gareus.org>
Date: Sun, 22 May 2022 00:16:22 +0200
Subject: [PATCH] LV2: pass patch-set messages to replicated plugin instances

This also fixes impulse analysis plugin display
---
 libs/ardour/ardour/lv2_plugin.h |  6 ++++++
 libs/ardour/lv2_plugin.cc       | 28 ++++++++++++++++++++++++++++
 2 files changed, 34 insertions(+)

diff --git a/libs/ardour/ardour/lv2_plugin.h b/libs/ardour/ardour/lv2_plugin.h
index ccbe187ff3..adb9bcc552 100644
--- a/libs/ardour/ardour/lv2_plugin.h
+++ b/libs/ardour/ardour/lv2_plugin.h
@@ -144,6 +144,9 @@ class LIBARDOUR_API LV2Plugin : public ARDOUR::Plugin, public ARDOUR::Workee
 	bool has_editor () const;
 	bool has_message_output () const;
 
+	void add_slave (boost::shared_ptr<Plugin>, bool);
+	void remove_slave (boost::shared_ptr<Plugin>);
+
 	bool write_from_ui(uint32_t       index,
 	                   uint32_t       protocol,
 	                   uint32_t       size,
@@ -299,6 +302,9 @@ class LIBARDOUR_API LV2Plugin : public ARDOUR::Plugin, public ARDOUR::Workee
 
 	Glib::Threads::Mutex _work_mutex;
 
+	Glib::Threads::Mutex                   _slave_lock;
+	std::set<boost::shared_ptr<LV2Plugin>> _slaves;
+
 #ifdef LV2_EXTENDED
 	static void queue_draw (LV2_Inline_Display_Handle);
 	static void midnam_update (LV2_Midnam_Handle);
diff --git a/libs/ardour/lv2_plugin.cc b/libs/ardour/lv2_plugin.cc
index 56fe3c2e80..b10a4ed0ba 100644
--- a/libs/ardour/lv2_plugin.cc
+++ b/libs/ardour/lv2_plugin.cc
@@ -1698,6 +1698,26 @@ LV2Plugin::has_editor() const
 	return _impl->ui != NULL;
 }
 
+void
+LV2Plugin::add_slave (boost::shared_ptr<Plugin> p, bool)
+{
+	boost::shared_ptr<LV2Plugin> lv2 = boost::dynamic_pointer_cast<LV2Plugin> (p);
+	if (lv2) {
+		Glib::Threads::Mutex::Lock lm (_slave_lock);
+		_slaves.insert (lv2);
+	}
+}
+
+void
+LV2Plugin::remove_slave (boost::shared_ptr<Plugin> p)
+{
+	boost::shared_ptr<LV2Plugin> lv2 = boost::dynamic_pointer_cast<LV2Plugin> (p);
+	if (lv2) {
+		Glib::Threads::Mutex::Lock lm (_slave_lock);
+		_slaves.erase (lv2);
+	}
+}
+
 bool
 LV2Plugin::has_message_output() const
 {
@@ -1761,6 +1781,14 @@ LV2Plugin::write_from_ui(uint32_t       index,
 		error << string_compose (_("LV2<%1>: Error writing from UI to plugin"), name()) << endmsg;
 		return false;
 	}
+
+	Glib::Threads::Mutex::Lock lm (_slave_lock, Glib::Threads::TRY_LOCK);
+	if (lm.locked()) {
+		for (auto const& i : _slaves) {
+			i->write_from_ui (index, protocol, size, body);
+		}
+	}
+
 	return true;
 }