Add manual reference counting to GetPluginFactory

Since even though we're passign raw pointers, it's expected that they
are actually `IPtr<T>`s.

src/plugin/bridges/vst3.cpp

@@ -81,13 +81,24 @@ Vst3PluginBridge::Vst3PluginBridge()
             overload{[&](const WantsConfiguration&)
                          -> WantsConfiguration::Response { return config; }});
     });
-
-    // Set up the plugin factory, since this is the first thing the host will
-    // request after loading the module. Host callback handlers should have
-    // started before this since the Wine plugin host will request a copy of the
-    // configuration during its initialization.
-    plugin_factory = std::make_unique<YaPluginFactoryPluginImpl>(*this);
-    sockets.host_vst_control.receive_into(
-        WantsPluginFactory{}, *plugin_factory,
-        std::pair<Vst3Logger&, bool>(logger, true));
+}
+
+Steinberg::IPluginFactory* Vst3PluginBridge::get_plugin_factory() {
+    // Even though we're working with raw pointers here, we should pretend that
+    // we're `IPtr<Steinberg::IPluginFactory>` and do the reference counting
+    // ourselves because you can't always safely pass those around
+    if (plugin_factory) {
+        plugin_factory->addRef();
+    } else {
+        // Set up the plugin factory, since this is the first thing the host
+        // will request after loading the module. Host callback handlers should
+        // have started before this since the Wine plugin host will request a
+        // copy of the configuration during its initialization.
+        plugin_factory = std::make_unique<YaPluginFactoryPluginImpl>(*this);
+        sockets.host_vst_control.receive_into(
+            WantsPluginFactory{}, *plugin_factory,
+            std::pair<Vst3Logger&, bool>(logger, true));
+    }
+
+    return plugin_factory.get();
 }