From 9023209dfd6973f08588a1963d383eefde385afc Mon Sep 17 00:00:00 2001
From: Jean Pierre Cimalando <jp-dev@inbox.ru>
Date: Wed, 28 Apr 2021 17:59:37 +0200
Subject: [PATCH] Add thread checker for the VST controller

---
 plugins/vst/SfizzVstController.cpp | 10 ++++++++++
 plugins/vst/SfizzVstController.h   |  2 ++
 2 files changed, 12 insertions(+)

diff --git a/plugins/vst/SfizzVstController.cpp b/plugins/vst/SfizzVstController.cpp
index eb658137..9f7b9246 100644
--- a/plugins/vst/SfizzVstController.cpp
+++ b/plugins/vst/SfizzVstController.cpp
@@ -10,6 +10,7 @@
 #include "SfizzVstIDs.h"
 #include "base/source/fstreamer.h"
 #include "base/source/updatehandler.h"
+#include <atomic>
 
 tresult PLUGIN_API SfizzVstControllerNoUi::initialize(FUnknown* context)
 {
@@ -20,6 +21,9 @@ tresult PLUGIN_API SfizzVstControllerNoUi::initialize(FUnknown* context)
     // initialize the update handler
     Steinberg::UpdateHandler::instance();
 
+    // initialize the thread checker
+    threadChecker_ = Vst::ThreadChecker::create();
+
     // create update objects
     queuedUpdates_ = Steinberg::owned(new QueuedUpdates);
     sfzUpdate_ = Steinberg::owned(new SfzUpdate);
@@ -228,6 +232,12 @@ tresult SfizzVstControllerNoUi::notify(Vst::IMessage* message)
     if (result != kResultFalse)
         return result;
 
+    if (!threadChecker_->test()) {
+        static std::atomic_bool warn_once_flag { false };
+        if (!warn_once_flag.exchange(true))
+            fprintf(stderr, "[sfizz] controller notification arrives from the wrong thread\n");
+    }
+
     const char* id = message->getMessageID();
     Vst::IAttributeList* attr = message->getAttributes();
 
diff --git a/plugins/vst/SfizzVstController.h b/plugins/vst/SfizzVstController.h
index db52179f..153bcd85 100644
--- a/plugins/vst/SfizzVstController.h
+++ b/plugins/vst/SfizzVstController.h
@@ -9,6 +9,7 @@
 #include "SfizzVstUpdates.h"
 #include "public.sdk/source/vst/vsteditcontroller.h"
 #include "public.sdk/source/vst/vstparameters.h"
+#include "public.sdk/source/common/threadchecker.h"
 #include "pluginterfaces/vst/ivstmidicontrollers.h"
 #include "vstgui/plugin-bindings/vst3editor.h"
 #include <sfizz_message.h>
@@ -44,6 +45,7 @@ public:
     REFCOUNT_METHODS(Vst::EditController)
 
 protected:
+    std::unique_ptr<Vst::ThreadChecker> threadChecker_;
     Steinberg::IPtr<QueuedUpdates> queuedUpdates_;
     Steinberg::IPtr<SfzUpdate> sfzUpdate_;
     Steinberg::IPtr<SfzDescriptionUpdate> sfzDescriptionUpdate_;