Allow creating IEditController instances

Now `IPluginFactory::createInstance()` can create multiple (and in our
case, all relevant) different types of objects.

src/common/logging/vst3.cpp

@@ -34,24 +34,29 @@ void Vst3Logger::log_unknown_interface(
 }
 
 void Vst3Logger::log_request(bool is_host_vst,
-                             const Vst3PluginProxy::Construct& args) {
+                             const Vst3PluginProxy::Construct& request) {
     log_request_base(is_host_vst, [&](auto& message) {
-        // TODO: When adding the enum class for instantiating different types,
-        //       make sure to reflect those in the constructor and destructor
-        //       logging
         message << "IPluginFactory::createComponent(cid = "
-                << format_uid(Steinberg::FUID::fromTUID(args.cid.data()))
-                << ", _iid = "
-                   "IComponent::iid, "
-                   "&obj)";
+                << format_uid(Steinberg::FUID::fromTUID(request.cid.data()))
+                << ", _iid = ";
+        switch (request.requested_interface) {
+            case Vst3PluginProxy::Construct::Interface::IComponent:
+                message << "IComponent::iid";
+                break;
+            case Vst3PluginProxy::Construct::Interface::IEditController:
+                message << "IEditController::iid";
+                break;
+        }
+        message << ", &obj)";
     });
 }
 
 void Vst3Logger::log_request(bool is_host_vst,
                              const Vst3PluginProxy::Destruct& request) {
     log_request_base(is_host_vst, [&](auto& message) {
-        message << "<IComponent* #" << request.instance_id
-                << ">::~IComponent()";
+        // We don't know what class this instance was originally instantiated
+        // as, but it also doesn't really matter
+        message << "<FUnknown* #" << request.instance_id << ">::~FUnknown()";
     });
 }
 

src/common/serialization/vst3/plugin-proxy.h

@@ -93,20 +93,29 @@ class Vst3PluginProxy : public YaAudioProcessor,
     /**
      * Message to request the Wine plugin host to instantiate a new IComponent
      * to pass through a call to `IComponent::createInstance(cid,
-     * IComponent::iid, ...)`.
+     * <requested_interface>::iid, ...)`.
      */
     struct Construct {
         using Response = std::variant<ConstructArgs, UniversalTResult>;
 
         ArrayUID cid;
 
-        // TODO: Add an enum class to reify the type of object we want to
-        //       instantiate so we can initialize things other than
-        //       `IComponent`, like `IEditController.`
+        /**
+         * The interface the host was trying to instantiate an object for.
+         * Technically the host can create any kind of object, but these are the
+         * objects that are actually used.
+         */
+        enum class Interface {
+            IComponent,
+            IEditController,
+        };
+
+        Interface requested_interface;
 
         template <typename S>
         void serialize(S& s) {
             s.container1b(cid);
+            s.value4b(requested_interface);
         }
     };