Fully implement IComponentHandlerBusActivation

We now support all VST 3.6.8 features. (or technically, also all VST
3.6.10 features)

src/common/serialization/vst3.h

@@ -180,7 +180,8 @@ void serialize(S& s, AudioProcessorRequest& payload) {
  * information we want or the operation we want to perform. A request of type
  * `CallbackRequest(T)` should send back a `T::Response`.
  */
-using CallbackRequest = std::variant<Vst3ContextMenuProxy::Destruct,
+using CallbackRequest =
+    std::variant<Vst3ContextMenuProxy::Destruct,
                  WantsConfiguration,
                  YaComponentHandler::BeginEdit,
                  YaComponentHandler::PerformEdit,
@@ -191,6 +192,7 @@ using CallbackRequest = std::variant<Vst3ContextMenuProxy::Destruct,
                  YaComponentHandler2::StartGroupEdit,
                  YaComponentHandler2::FinishGroupEdit,
                  YaComponentHandler3::CreateContextMenu,
+                 YaComponentHandlerBusActivation::RequestBusActivation,
                  // Used when the host uses proxy objects,
                  // and we have to route
                  // `IConnectionPoint::notify` calls through

src/plugin/bridges/vst3-impls/plugin-proxy.cpp

@@ -449,6 +449,7 @@ tresult PLUGIN_API Vst3PluginProxyImpl::setComponentHandler(
         // callback later
         component_handler_2 = component_handler;
         component_handler_3 = component_handler;
+        component_handler_bus_activation = component_handler;
         unit_handler = component_handler;
         unit_handler_2 = component_handler;
 

src/plugin/bridges/vst3-impls/plugin-proxy.h

@@ -334,6 +334,8 @@ class Vst3PluginProxyImpl : public Vst3PluginProxy {
         component_handler_2;
     Steinberg::FUnknownPtr<Steinberg::Vst::IComponentHandler3>
         component_handler_3;
+    Steinberg::FUnknownPtr<Steinberg::Vst::IComponentHandlerBusActivation>
+        component_handler_bus_activation;
     Steinberg::FUnknownPtr<Steinberg::Vst::IUnitHandler> unit_handler;
     Steinberg::FUnknownPtr<Steinberg::Vst::IUnitHandler2> unit_handler_2;
 

src/plugin/bridges/vst3.cpp

@@ -149,6 +149,17 @@ Vst3PluginBridge::Vst3PluginBridge()
                             .context_menu_args = std::nullopt};
                     }
                 },
+                [&](const YaComponentHandlerBusActivation::RequestBusActivation&
+                        request) -> YaComponentHandlerBusActivation::
+                                     RequestBusActivation::Response {
+                                         return plugin_proxies
+                                             .at(request.owner_instance_id)
+                                             .get()
+                                             .component_handler_bus_activation
+                                             ->requestBusActivation(
+                                                 request.type, request.dir,
+                                                 request.index, request.state);
+                                     },
                 [&](const YaContextMenu::GetItemCount& request)
                     -> YaContextMenu::GetItemCount::Response {
                     return plugin_proxies.at(request.owner_instance_id)

src/wine-host/bridges/vst3-impls/component-handler-proxy.cpp

@@ -119,10 +119,13 @@ tresult PLUGIN_API Vst3ComponentHandlerProxyImpl::requestBusActivation(
     Steinberg::Vst::BusDirection dir,
     int32 index,
     TBool state) {
-    // TODO: Implement
+    return bridge.send_message(
-    std::cerr << "TODO: IComponentHandlerBusActivation::requestBusActivation()"
+        YaComponentHandlerBusActivation::RequestBusActivation{
-              << std::endl;
+            .owner_instance_id = owner_instance_id(),
-    return Steinberg::kNotImplemented;
+            .type = type,
+            .dir = dir,
+            .index = index,
+            .state = state});
 }
 
 tresult PLUGIN_API Vst3ComponentHandlerProxyImpl::notifyUnitSelection(