Send the factory from the Wine host to the plugin

src/common/communication/vst3.h

@@ -178,7 +178,7 @@ class Vst3MessageHandler : public AdHocSocketHandler<Thread> {
                         request);
                 }
 
-                const auto response = callback(request);
+                const auto& response = callback(request);
                 if (logging) {
                     auto [logger, is_host_vst] = *logging;
                     logger.log_response(!is_host_vst, response);

src/common/serialization/vst3.h

@@ -50,7 +50,9 @@ struct WantsConfiguration {
  * copy of the hosted Windows VST3 plugin's `IPluginFactory{,2,3}` interface.
  */
 struct WantsPluginFactory {
-    using Response = YaPluginFactory;
+    // TODO: Some things had to be changed to use references since this is an
+    //       abstract class. Check if nothing breaks.
+    using Response = YaPluginFactory&;
 };
 
 /**

src/plugin/vst3-plugin.cpp

@@ -73,6 +73,10 @@ SMTG_EXPORT_SYMBOL Steinberg::IPluginFactory* PLUGIN_API GetPluginFactory() {
     // The host should have called `InitModule()` first
     assert(bridge);
 
+    // TODO: I think there is a flag that indicates that the class configuration
+    //       may change, but I don't remember if it's at runtime or every time
+    //       the module is loaded. If it's the former then this will take some
+    //       special handling.
     return bridge->plugin_factory.get();
 
     // TODO: In the normal implementation of this function they manually call

src/wine-host/bridges/vst3.cpp

@@ -36,6 +36,11 @@ Vst3Bridge::Vst3Bridge(MainContext& main_context,
 
     sockets.connect();
 
+    // Serialize the plugin's plugin factory. The native VST3 plugin will
+    // request a copy of this during its initialization.
+    plugin_factory =
+        std::make_unique<YaPluginFactoryHostImpl>(module->getFactory().get());
+
     // Fetch this instance's configuration from the plugin to finish the setup
     // process
     config = sockets.vst_host_callback.send_message(WantsConfiguration{},
@@ -43,18 +48,12 @@ Vst3Bridge::Vst3Bridge(MainContext& main_context,
 }
 
 void Vst3Bridge::run() {
-    // TODO: Remove, this is just for type checking
-    if (false) {
-        boost::asio::local::stream_protocol::socket* socket;
-        Steinberg::IPtr<Steinberg::IPluginFactory> factory;
-        YaPluginFactoryHostImpl object(factory);
-        write_object(*socket, object);
-    }
-
-    // TODO: Handle events
-    // sockets.host_vst_control.receive_messages(
-    //     std::nullopt, [&](ControlRequest request) -> ControlResponse {
-    //     });
-
-    std::cerr << "TODO: Not yet implemented" << std::endl;
+    sockets.host_vst_control.receive_messages(
+        std::nullopt, [&](ControlRequest request) -> auto& {
+            return std::visit(overload{[&](const WantsPluginFactory&)
+                                           -> WantsPluginFactory::Response {
+                                  return *plugin_factory;
+                              }},
+                              request);
+        });
 }

src/wine-host/bridges/vst3.h

@@ -83,4 +83,11 @@ class Vst3Bridge : public HostBridge {
      *       threads to exit.
      */
     Vst3Sockets<Win32Thread> sockets;
+
+    /**
+     * A plugin factory copied from the Windows VST3 plugin during
+     * initialization. The native VST3 plugin will request a copy of this
+     * information during its initialization.
+     */
+    std::unique_ptr<YaPluginFactory> plugin_factory;
 };