From 1bf9ebb4b113bf2dc3c4537974cd81f1cca67a97 Mon Sep 17 00:00:00 2001
From: reuk <reuk@users.noreply.github.com>
Date: Wed, 9 Feb 2022 13:06:20 +0000
Subject: [PATCH] VST3 Host:  Avoid calling initialize twice on objects that
 implement both IComponent and IEditController

---
 .../format_types/juce_VST3PluginFormat.cpp    | 49 ++++++++++++++-----
 1 file changed, 38 insertions(+), 11 deletions(-)

diff --git a/modules/juce_audio_processors/format_types/juce_VST3PluginFormat.cpp b/modules/juce_audio_processors/format_types/juce_VST3PluginFormat.cpp
index 2b6e980749..05997fc7cd 100644
--- a/modules/juce_audio_processors/format_types/juce_VST3PluginFormat.cpp
+++ b/modules/juce_audio_processors/format_types/juce_VST3PluginFormat.cpp
@@ -1348,9 +1348,7 @@ struct VST3PluginWindow : public AudioProcessorEditor,
         warnOnFailure (view->setFrame (this));
         view->queryInterface (Steinberg::IPlugViewContentScaleSupport::iid, (void**) &scaleInterface);
 
-        if (scaleInterface != nullptr)
-            warnOnFailure (scaleInterface->setContentScaleFactor ((Steinberg::IPlugViewContentScaleSupport::ScaleFactor) nativeScaleFactor));
-
+        setContentScaleFactor();
         resizeToFit();
     }
 
@@ -1598,11 +1596,24 @@ private:
     void updatePluginScale()
     {
         if (scaleInterface != nullptr)
-            warnOnFailure (scaleInterface->setContentScaleFactor ((Steinberg::IPlugViewContentScaleSupport::ScaleFactor) nativeScaleFactor));
+            setContentScaleFactor();
         else
             resizeToFit();
     }
 
+    void setContentScaleFactor()
+    {
+        if (scaleInterface != nullptr)
+        {
+            const auto result = scaleInterface->setContentScaleFactor ((Steinberg::IPlugViewContentScaleSupport::ScaleFactor) nativeScaleFactor);
+            ignoreUnused (result);
+
+           #if ! JUCE_MAC
+            ignoreUnused (warnOnFailure (result));
+           #endif
+        }
+    }
+
     //==============================================================================
     Atomic<int> refCount { 1 };
     VSTComSmartPtr<IPlugView> view;
@@ -1676,16 +1687,33 @@ struct VST3ComponentHolder
     // transfers ownership to the plugin instance!
     AudioPluginInstance* createPluginInstance();
 
+    bool isIComponentAlsoIEditController() const
+    {
+        if (component == nullptr)
+        {
+            jassertfalse;
+            return false;
+        }
+
+        return VSTComSmartPtr<Vst::IEditController>().loadFrom (component);
+    }
+
     bool fetchController (VSTComSmartPtr<Vst::IEditController>& editController)
     {
         if (! isComponentInitialised && ! initialise())
             return false;
 
+        editController.loadFrom (component);
+
         // Get the IEditController:
         TUID controllerCID = { 0 };
 
-        if (component->getControllerClassId (controllerCID) == kResultTrue && FUID (controllerCID).isValid())
+        if (editController == nullptr
+            && component->getControllerClassId (controllerCID) == kResultTrue
+            && FUID (controllerCID).isValid())
+        {
             editController.loadFrom (factory, controllerCID);
+        }
 
         if (editController == nullptr)
         {
@@ -1702,9 +1730,6 @@ struct VST3ComponentHolder
             }
         }
 
-        if (editController == nullptr)
-            editController.loadFrom (component);
-
         return (editController != nullptr);
     }
 
@@ -2220,7 +2245,7 @@ public:
 
         editController->setComponentHandler (nullptr);
 
-        if (isControllerInitialised)
+        if (isControllerInitialised && ! holder->isIComponentAlsoIEditController())
             editController->terminate();
 
         holder->terminate();
@@ -2252,8 +2277,10 @@ public:
         if (! (isControllerInitialised || holder->fetchController (editController)))
             return false;
 
-        // (May return an error if the plugin combines the IComponent and IEditController implementations)
-        editController->initialize (holder->host->getFUnknown());
+        // If the IComponent and IEditController are the same, we will have
+        // already initialized the object at this point and should avoid doing so again.
+        if (! holder->isIComponentAlsoIEditController())
+            editController->initialize (holder->host->getFUnknown());
 
         isControllerInitialised = true;
         editController->setComponentHandler (holder->host);