Add a (nonfunctional) VST3 entry point

meson.build

@@ -196,6 +196,29 @@ if with_vst3
     link_with : vst3_sdk_hosting_wine,
     include_directories : vst3_include_dir,
   )
+
+  # This is the VST3 equivalent of `libyabridge-vst2.so`. The Wine host
+  # applications can handle both VST2 and VST3 plugins.
+  shared_library(
+    'yabridge-vst3',
+    [
+      'src/common/logging.cpp',
+      'src/plugin/vst3-plugin.cpp',
+      version_header,
+    ],
+    native : true,
+    include_directories : include_dir,
+    dependencies : [
+      boost_dep,
+      boost_filesystem_dep,
+      bitsery_dep,
+      threads_dep,
+      tomlplusplus_dep,
+      vst3_sdk_native_dep,
+    ],
+    cpp_args : compiler_options,
+    link_args : ['-ldl'],
+  )
 else
   message('VST3 support has been disabled')
 endif

src/plugin/vst3-plugin.cpp

@@ -0,0 +1,65 @@
+#include <public.sdk/source/main/pluginfactory.h>
+
+// TODO: Should you include this implementation file or copy everything over?
+#include <public.sdk/source/main/linuxmain.cpp>
+
+using Steinberg::gPluginFactory;
+
+// TODO: What should we do here? Also, note to self, don't forget to call these
+//       on the Wine host side if the host SDK doesn't already do that for us.
+bool InitModule() {
+    return true;
+}
+
+bool DeinitModule() {
+    return true;
+}
+
+/**
+ * Our VST3 plugin's entry point. When building the plugin factory we'll host
+ * the plugin in our Wine application, retrieve its information and supported
+ * classes, and then recreate it here.
+ */
+SMTG_EXPORT_SYMBOL Steinberg::IPluginFactory* PLUGIN_API GetPluginFactory() {
+    // TODO: So from this I can imagine that the host is supposed to keep this
+    //       module loaded into memory and reuse it for multiple plugins? How
+    //       should Wine host instances be tied to native plugin instances?
+    if (!gPluginFactory) {
+        // TODO: Here we want to:
+        //       1) Load the plugin on the Wine host
+        //       2) Create a factory using the plugins PFactoryInfo
+        //       3) Get all PClassInfo{,2,W} objects from the plugin, register
+        //          those classes.
+        //
+        //       We should wrap this in our `Vst3PluginBridge`
+
+        // static Steinberg::PFactoryInfo factoryInfo(vendor, url, email,
+        // flags); gPluginFactory = new Steinberg::CPluginFactory(factoryInfo);
+
+        //
+        // {
+        //     Steinberg::TUID lcid = cid;
+        //     static Steinberg::PClassInfo componentClass(lcid, cardinality,
+        //                                                 category, name);
+        //     gPluginFactory->registerClass(&componentClass, createMethod);
+        // }
+        // {
+        //     Steinberg::TUID lcid = cid;
+        //     static Steinberg::PClassInfo2 componentClass(
+        //         lcid, cardinality, category, name, classFlags, subCategories,
+        //         0, version, sdkVersion);
+        //     gPluginFactory->registerClass(&componentClass, createMethod);
+        // }
+        // {
+        //     TUID lcid = cid;
+        //     static Steinberg::PClassInfoW componentClass(
+        //         lcid, cardinality, category, name, classFlags, subCategories,
+        //         0, version, sdkVersion);
+        //     gPluginFactory->registerClass(&componentClass, createMethod);
+        // }
+    } else {
+        gPluginFactory->addRef();
+    }
+
+    return gPluginFactory;
+}