Split IPluginBase from IComponent

We're also going to need this for `IEditController`. Separating all of
these classes will also keep everything much more maintainable with all
of these associated structs.

src/wine-host/bridges/vst3.cpp

@@ -26,7 +26,9 @@ ComponentInstance::ComponentInstance() {}
 
 ComponentInstance::ComponentInstance(
     Steinberg::IPtr<Steinberg::Vst::IComponent> component)
-    : component(component), audio_processor(component) {}
+    : component(component),
+      plugin_base(component),
+      audio_processor(component) {}
 
 Vst3Bridge::Vst3Bridge(MainContext& main_context,
                        std::string plugin_dll_path,
@@ -86,8 +88,8 @@ void Vst3Bridge::run() {
 
                 return Ack{};
             },
-            [&](YaComponent::Initialize& request)
-                -> YaComponent::Initialize::Response {
+            [&](YaPluginBase::Initialize& request)
+                -> YaPluginBase::Initialize::Response {
                 // If we got passed a host context, we'll create a proxy object
                 // and pass that to the initialize function. This object should
                 // be cleaned up again during `YaComponent::Destruct`.
@@ -103,12 +105,12 @@ void Vst3Bridge::run() {
                 }
 
                 return component_instances[request.instance_id]
-                    .component->initialize(context);
+                    .plugin_base->initialize(context);
             },
-            [&](const YaComponent::Terminate& request)
-                -> YaComponent::Terminate::Response {
+            [&](const YaPluginBase::Terminate& request)
+                -> YaPluginBase::Terminate::Response {
                 return component_instances[request.instance_id]
-                    .component->terminate();
+                    .plugin_base->terminate();
             },
             [&](const YaComponent::SetIoMode& request)
                 -> YaComponent::SetIoMode::Response {

src/wine-host/bridges/vst3.h

@@ -28,6 +28,9 @@
  * A holder for an `IComponent` instance created from the factory along with any
  * host context proxy objects belonging to it, and several predefined
  * `FUnknownPtrs` so we don't have to do these dynamic casts all the times..
+ *
+ * TODO: When implementing `IEditController`, change this to use `IPluginBase`
+ *       as the base interface.
  */
 struct ComponentInstance {
     ComponentInstance();
@@ -37,7 +40,7 @@ struct ComponentInstance {
     /**
      * If the host passes an `IHostApplication` during
      * `IPluginBase::initialize()`, we'll store a proxy object here and then
-     * pass it to `component->initialize()`.
+     * pass it to `plugin_base->initialize()`.
      */
     Steinberg::IPtr<YaHostApplication> hsot_application_context;
 
@@ -49,6 +52,7 @@ struct ComponentInstance {
     // All smart pointers below are created from `component`. They will be null
     // pointers if `component` did not implement the interface.
 
+    Steinberg::FUnknownPtr<Steinberg::IPluginBase> plugin_base;
     Steinberg::FUnknownPtr<Steinberg::Vst::IAudioProcessor> audio_processor;
 };