VST threading: prevent concurrent effSetChunk and process()

This is a potential fix for unreliable preset load/restore.
(http://mixbus.harrisonconsoles.com/forum/thread-1970-post-21486.html#pid21486)

Since a Glib Mutex can't be copy-constructed an explicit copy c'tor
is needed.

1 files changed, 3 insertions, 0 deletions

diff --git a/libs/ardour/ardour/vst_plugin.h b/libs/ardour/ardour/vst_plugin.h
index e56b9c005c..182b432692 100644
--- a/libs/ardour/ardour/vst_plugin.h
+++ b/libs/ardour/ardour/vst_plugin.h
@@ -40,6 +40,7 @@ class LIBARDOUR_API VSTPlugin : public Plugin
 {
 public:
 	VSTPlugin (AudioEngine &, Session &, VSTHandle *);
+	VSTPlugin (const VSTPlugin& other);
 	virtual ~VSTPlugin ();
 
 	void activate ();
@@ -119,6 +120,8 @@ protected:
 	framepos_t _transport_frame;
 	float      _transport_speed;
 	mutable std::map <uint32_t, float> _parameter_defaults;
+
+	Glib::Threads::Mutex _state_lock;
 };
 
 }