Implement IComponentHandler::beginEdit()

src/common/logging/vst3.cpp

@@ -446,6 +446,14 @@ bool Vst3Logger::log_request(bool is_host_vst, const WantsConfiguration&) {
     });
 }
 
+bool Vst3Logger::log_request(bool is_host_vst,
+                             const YaComponentHandler::BeginEdit& request) {
+    return log_request_base(is_host_vst, [&](auto& message) {
+        message << request.owner_instance_id
+                << ": IComponentHandler::beginEdit(" << request.id << ")";
+    });
+}
+
 void Vst3Logger::log_response(bool is_host_vst, const Ack&) {
     log_response_base(is_host_vst, [&](auto& message) { message << "ACK"; });
 }

src/common/logging/vst3.h

@@ -108,7 +108,9 @@ class Vst3Logger {
     bool log_request(bool is_host_vst, const YaPluginBase::Terminate&);
     bool log_request(bool is_host_vst, const YaPluginFactory::Construct&);
     bool log_request(bool is_host_vst, const YaPluginFactory::SetHostContext&);
+
     bool log_request(bool is_host_vst, const WantsConfiguration&);
+    bool log_request(bool is_host_vst, const YaComponentHandler::BeginEdit&);
 
     void log_response(bool is_host_vst, const Ack&);
     void log_response(

src/common/serialization/vst3.h

@@ -105,7 +105,8 @@ void serialize(S& s, ControlRequest& 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<WantsConfiguration>;
+using CallbackRequest =
+    std::variant<WantsConfiguration, YaComponentHandler::BeginEdit>;
 
 template <typename S>
 void serialize(S& s, CallbackRequest& payload) {

src/common/serialization/vst3/component-handler/component-handler.h

@@ -61,6 +61,24 @@ class YaComponentHandler : public Steinberg::Vst::IComponentHandler {
 
     inline bool supported() const { return arguments.supported; }
 
+    /**
+     * Message to pass through a call to `IComponentHandler::beginEdit(id)` to
+     * the component handler provided by the host.
+     */
+    struct BeginEdit {
+        using Response = UniversalTResult;
+
+        native_size_t owner_instance_id;
+
+        Steinberg::Vst::ParamID id;
+
+        template <typename S>
+        void serialize(S& s) {
+            s.value8b(owner_instance_id);
+            s.value4b(id);
+        }
+    };
+
     virtual tresult PLUGIN_API
     beginEdit(Steinberg::Vst::ParamID id) override = 0;
     virtual tresult PLUGIN_API

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

@@ -122,9 +122,6 @@ class Vst3PluginProxyImpl : public Vst3PluginProxy {
     tresult PLUGIN_API initialize(FUnknown* context) override;
     tresult PLUGIN_API terminate() override;
 
-   private:
-    Vst3PluginBridge& bridge;
-
     /**
      * An `IHostApplication` instance if we get one through
      * `IPluginBase::initialize()`. This should be the same for all plugin
@@ -141,4 +138,7 @@ class Vst3PluginProxyImpl : public Vst3PluginProxy {
      * to this object.
      */
     Steinberg::IPtr<Steinberg::Vst::IComponentHandler> component_handler;
+
+   private:
+    Vst3PluginBridge& bridge;
 };

src/plugin/bridges/vst3.cpp

@@ -79,8 +79,17 @@ Vst3PluginBridge::Vst3PluginBridge()
     host_callback_handler = std::jthread([&]() {
         sockets.vst_host_callback.receive_messages(
             std::pair<Vst3Logger&, bool>(logger, false),
-            overload{[&](const WantsConfiguration&)
-                         -> WantsConfiguration::Response { return config; }});
+            overload{
+                [&](const WantsConfiguration&) -> WantsConfiguration::Response {
+                    return config;
+                },
+                [&](const YaComponentHandler::BeginEdit& request)
+                    -> YaComponentHandler::BeginEdit::Response {
+                    return plugin_proxies.at(request.owner_instance_id)
+                        .get()
+                        .component_handler->beginEdit(request.id);
+                },
+            });
     });
 }
 

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

@@ -41,9 +41,8 @@ Vst3ComponentHandlerProxyImpl::queryInterface(const Steinberg::TUID _iid,
 
 tresult PLUGIN_API
 Vst3ComponentHandlerProxyImpl::beginEdit(Steinberg::Vst::ParamID id) {
-    // TODO: Implement
-    std::cerr << "TODO: IComponentHandler::beginEdit()" << std::endl;
-    return Steinberg::kNotImplemented;
+    return bridge.send_message(YaComponentHandler::BeginEdit{
+        .owner_instance_id = owner_instance_id(), .id = id});
 }
 
 tresult PLUGIN_API Vst3ComponentHandlerProxyImpl::performEdit(

src/wine-host/bridges/vst3.h

@@ -103,6 +103,16 @@ class Vst3Bridge : public HostBridge {
      */
     void run() override;
 
+    /**
+     * Send a callback message to the host return the response. This is a
+     * shorthand for `sockets.vst_host_callback.send_message` for use in VST3
+     * interface implementations.
+     */
+    template <typename T>
+    typename T::Response send_message(const T& object) {
+        return sockets.vst_host_callback.send_message(object, std::nullopt);
+    }
+
    private:
     /**
      * Generate a nique instance identifier using an atomic fetch-and-add. This