Implement IPlugView::isPLatformTypeSupported()

This of course requires us to substitute the relevant Linux platform
type for the Win32 one.

src/common/logging/vst3.cpp

@@ -432,6 +432,21 @@ bool Vst3Logger::log_request(bool is_host_vst,
     });
 }
 
+bool Vst3Logger::log_request(
+    bool is_host_vst,
+    const YaPlugView::IsPlatformTypeSupported& request) {
+    return log_request_base(is_host_vst, [&](auto& message) {
+        message << request.owner_instance_id
+                << ": IPlugView::isPLatformTypeSupported(type = \""
+                << request.type;
+        if (request.type == Steinberg::kPlatformTypeX11EmbedWindowID) {
+            message << "\" (will be translated to \""
+                    << Steinberg::kPlatformTypeHWND << "\")";
+        }
+        message << ")";
+    });
+}
+
 bool Vst3Logger::log_request(bool is_host_vst,
                              const YaPluginBase::Initialize& request) {
     return log_request_base(is_host_vst, [&](auto& message) {

src/common/logging/vst3.h

@@ -108,6 +108,8 @@ class Vst3Logger {
     bool log_request(bool is_host_vst,
                      const YaEditController::SetComponentHandler&);
     bool log_request(bool is_host_vst, const YaEditController::CreateView&);
+    bool log_request(bool is_host_vst,
+                     const YaPlugView::IsPlatformTypeSupported&);
     bool log_request(bool is_host_vst, const YaPluginBase::Initialize&);
     bool log_request(bool is_host_vst, const YaPluginBase::Terminate&);
     bool log_request(bool is_host_vst, const YaPluginFactory::Construct&);

src/common/serialization/vst3.h

@@ -92,6 +92,7 @@ using ControlRequest = std::variant<Vst3PlugViewProxy::Destruct,
                                     YaEditController::SetParamNormalized,
                                     YaEditController::SetComponentHandler,
                                     YaEditController::CreateView,
+                                    YaPlugView::IsPlatformTypeSupported,
                                     YaPluginBase::Initialize,
                                     YaPluginBase::Terminate,
                                     YaPluginFactory::Construct,

src/common/serialization/vst3/plug-view/plug-view.h

@@ -61,6 +61,27 @@ class YaPlugView : public Steinberg::IPlugView {
 
     inline bool supported() const { return arguments.supported; }
 
+    /**
+     * Message to pass through a call to
+     * `IPlugView::isPlatformTypeSupported(type)` to the Wine plugin host. We
+     * will of course change `kPlatformStringLinux` for `kPlatformStringWin`,
+     * because why would a Windows VST3 plugin have X11 support? (and how would
+     * that even work)
+     */
+    struct IsPlatformTypeSupported {
+        using Response = UniversalTResult;
+
+        native_size_t owner_instance_id;
+
+        std::string type;
+
+        template <typename S>
+        void serialize(S& s) {
+            s.value8b(owner_instance_id);
+            s.text1b(type, 128);
+        }
+    };
+
     virtual tresult PLUGIN_API
     isPlatformTypeSupported(Steinberg::FIDString type) override = 0;
     virtual tresult PLUGIN_API attached(void* parent,

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

@@ -42,9 +42,10 @@ Vst3PlugViewProxyImpl::queryInterface(const Steinberg::TUID _iid, void** obj) {
 
 tresult PLUGIN_API
 Vst3PlugViewProxyImpl::isPlatformTypeSupported(Steinberg::FIDString type) {
-    // TODO: Implement
+    // We'll swap the X11 window ID platform type string for the Win32 HWND
-    bridge.logger.log("TODO: IPlugView::isPlatformTypeSupported()");
+    // equivalent on the Wine side
-    return Steinberg::kNotImplemented;
+    return bridge.send_message(YaPlugView::IsPlatformTypeSupported{
+        .owner_instance_id = owner_instance_id(), .type = type});
 }
 
 tresult PLUGIN_API Vst3PlugViewProxyImpl::attached(void* parent,

src/wine-host/bridges/vst3.cpp

@@ -398,6 +398,19 @@ void Vst3Bridge::run() {
                                    request.instance_id)
                              : std::nullopt)};
             },
+            [&](const YaPlugView::IsPlatformTypeSupported& request)
+                -> YaPlugView::IsPlatformTypeSupported::Response {
+                // The host will of course want to pass an X11 window ID for the
+                // plugin to embed itself in, so we'll have to translate this to
+                // a HWND
+                const std::string type =
+                    request.type == Steinberg::kPlatformTypeX11EmbedWindowID
+                        ? Steinberg::kPlatformTypeHWND
+                        : request.type;
+
+                return object_instances[request.owner_instance_id]
+                    .plug_view->isPlatformTypeSupported(type.c_str());
+            },
             [&](YaPluginBase::Initialize& request)
                 -> YaPluginBase::Initialize::Response {
                 // If we got passed a host context, we'll create a proxy object