From 8f3a13d998e812e1c997bd8485b0d5c7b7ff9809 Mon Sep 17 00:00:00 2001
From: Robin Gareus <robin@gareus.org>
Date: Sat, 19 Mar 2016 18:03:36 +0100
Subject: [PATCH] hotfix for concurrent lua interpreter calls

ToDo: localize parameter descriptor in init()
---
 libs/ardour/ardour/luaproc.h | 3 +++
 libs/ardour/luaproc.cc       | 7 +++++++
 2 files changed, 10 insertions(+)

diff --git a/libs/ardour/ardour/luaproc.h b/libs/ardour/ardour/luaproc.h
index d0560e9953..062aad9fff 100644
--- a/libs/ardour/ardour/luaproc.h
+++ b/libs/ardour/ardour/luaproc.h
@@ -142,6 +142,9 @@ private:
 	int64_t _stats_max[2];
 	int64_t _stats_cnt;
 #endif
+
+	mutable Glib::Threads::Mutex debug_hack; // prevent concurrent calls to  _lua_dsp() and _lua_params() -- test/debug
+
 };
 
 class LIBARDOUR_API LuaPluginInfo : public PluginInfo
diff --git a/libs/ardour/luaproc.cc b/libs/ardour/luaproc.cc
index a030691e9f..2669f3a03f 100644
--- a/libs/ardour/luaproc.cc
+++ b/libs/ardour/luaproc.cc
@@ -531,6 +531,7 @@ LuaProc::connect_and_run (BufferSet& bufs,
 
 	try {
 		if (_lua_does_channelmapping) {
+			Glib::Threads::Mutex::Lock lm (debug_hack);
 			// run the DSP function
 			(*_lua_dsp)(&bufs, in, out, nframes, offset);
 		} else {
@@ -594,6 +595,7 @@ LuaProc::connect_and_run (BufferSet& bufs,
 			}
 
 
+			Glib::Threads::Mutex::Lock lm (debug_hack);
 			// run the DSP function
 			(*_lua_dsp)(in_map, out_map, nframes);
 		}
@@ -747,6 +749,7 @@ LuaProc::default_value (uint32_t port)
 		return 0;
 	}
 	int lp = _ctrl_params[port].second;
+	Glib::Threads::Mutex::Lock lm (debug_hack);
 	luabridge::LuaRef lr = (*_lua_params)[lp];
 	return (lr["default"]).cast<float> ();
 }
@@ -778,6 +781,7 @@ LuaProc::get_parameter_descriptor (uint32_t port, ParameterDescriptor& desc) con
 	assert (port <= parameter_count ());
 	int lp = _ctrl_params[port].second;
 
+	Glib::Threads::Mutex::Lock lm (debug_hack);
 	luabridge::LuaRef lr = (*_lua_params)[lp];
 	desc.lower  = (lr["min"]).cast<float> ();
 	desc.upper  = (lr["max"]).cast<float> ();
@@ -814,6 +818,7 @@ std::string
 LuaProc::get_parameter_docs (uint32_t port) const {
 	assert (port <= parameter_count ());
 	int lp = _ctrl_params[port].second;
+	Glib::Threads::Mutex::Lock lm (debug_hack);
 	luabridge::LuaRef lr = (*_lua_params)[lp];
 	luabridge::LuaRef doc = lr["doc"];
 	if (doc.isString ()) {
@@ -864,6 +869,7 @@ LuaProc::describe_parameter (Evoral::Parameter param)
 {
 	if (param.type () == PluginAutomation && param.id () < parameter_count ()) {
 		int lp = _ctrl_params[param.id ()].second;
+		Glib::Threads::Mutex::Lock lm (debug_hack);
 		luabridge::LuaRef lr = (*_lua_params)[lp];
 		return (lr["name"]).cast<std::string> ();
 	} else {
@@ -887,6 +893,7 @@ boost::shared_ptr<ScalePoints>
 LuaProc::get_scale_points (uint32_t port) const
 {
 	int lp = _ctrl_params[port].second;
+	Glib::Threads::Mutex::Lock lm (debug_hack);
 	luabridge::LuaRef lr = (*_lua_params)[lp];
 
 	if (!lr["scalepoints"].isTable()) {