Implement IConnectionPoint::notify

src/common/logging/vst3.cpp

@@ -108,6 +108,21 @@ bool Vst3Logger::log_request(bool is_host_vst,
     });
 }
 
+bool Vst3Logger::log_request(bool is_host_vst,
+                             const YaConnectionPoint::Notify& request) {
+    return log_request_base(is_host_vst, [&](auto& message) {
+        message << request.instance_id
+                << ": IConnectionPoint::notify(message = <IMessage* ";
+        if (const char* id =
+                const_cast<YaMessage&>(request.message).getMessageID()) {
+            message << "with ID = \"" << id << "\"";
+        } else {
+            message << "without an ID";
+        }
+        message << ">)";
+    });
+}
+
 bool Vst3Logger::log_request(
     bool is_host_vst,
     const YaEditController::SetComponentState& request) {

src/common/logging/vst3.h

@@ -66,6 +66,7 @@ class Vst3Logger {
     bool log_request(bool is_host_vst, const Vst3PluginProxy::GetState&);
     bool log_request(bool is_host_vst, const YaConnectionPoint::Connect&);
     bool log_request(bool is_host_vst, const YaConnectionPoint::Disconnect&);
+    bool log_request(bool is_host_vst, const YaConnectionPoint::Notify&);
     bool log_request(bool is_host_vst,
                      const YaEditController::SetComponentState&);
     bool log_request(bool is_host_vst,

src/common/serialization/vst3.h

@@ -68,6 +68,7 @@ using ControlRequest = std::variant<Vst3PlugViewProxy::Destruct,
                                     Vst3PluginProxy::GetState,
                                     YaConnectionPoint::Connect,
                                     YaConnectionPoint::Disconnect,
+                                    YaConnectionPoint::Notify,
                                     YaEditController::SetComponentState,
                                     YaEditController::GetParameterCount,
                                     YaEditController::GetParameterInfo,

src/common/serialization/vst3/plugin/connection-point.h

@@ -21,6 +21,7 @@
 
 #include "../../common.h"
 #include "../base.h"
+#include "../message.h"
 
 #pragma GCC diagnostic push
 #pragma GCC diagnostic ignored "-Wnon-virtual-dtor"
@@ -119,6 +120,30 @@ class YaConnectionPoint : public Steinberg::Vst::IConnectionPoint {
     };
 
     virtual tresult PLUGIN_API disconnect(IConnectionPoint* other) override = 0;
+
+    /**
+     * Message to pass through a call to `IConnectionPoint::notify(message)` to
+     * the Wine plugin host. Since `IAttributeList` does not have any way to
+     * iterate over all values, we only support messages sent by plugins using
+     * our own implementation of the interface, since there's no way to
+     * serialize them otherwise. This `IConnectionPoint::notify()`
+     * implementation is also only used with hosts that do not connect objects
+     * directly and use connection proxies instead.
+     */
+    struct Notify {
+        using Response = UniversalTResult;
+
+        native_size_t instance_id;
+
+        YaMessage message;
+
+        template <typename S>
+        void serialize(S& s) {
+            s.value8b(instance_id);
+            s.object(message);
+        }
+    };
+
     virtual tresult PLUGIN_API
     notify(Steinberg::Vst::IMessage* message) override = 0;
 

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

@@ -246,9 +246,22 @@ tresult PLUGIN_API Vst3PluginProxyImpl::disconnect(IConnectionPoint* other) {
 
 tresult PLUGIN_API
 Vst3PluginProxyImpl::notify(Steinberg::Vst::IMessage* message) {
-    // TODO: Implement
+    // Since there is no way to enumerate over all values in an
-    bridge.logger.log("TODO IConnectionPoint::notify()");
+    // `IAttributeList`, we can only support relaying messages that were sent by
-    return Steinberg::kNotImplemented;
+    // our own objects. This is only needed to support hosts that place a
+    // connection proxy between two objects instead of connecting them directly.
+    // If the objects are connected directly we also connected them directly on
+    // the Wine side, so we don't have to do any additional when those objects
+    // pass through messages.
+    if (auto message_impl = dynamic_cast<YaMessage*>(message)) {
+        return bridge.send_message(YaConnectionPoint::Notify{
+            .instance_id = instance_id(), .message = *message_impl});
+    } else {
+        bridge.logger.log(
+            "WARNING: Unknown message type passed to "
+            "'IConnectionPoint::notify()', ignoring");
+        return Steinberg::kNotImplemented;
+    }
 }
 
 tresult PLUGIN_API

src/wine-host/bridges/vst3.cpp

@@ -187,6 +187,11 @@ void Vst3Bridge::run() {
                         object_instances[request.other_instance_id]
                             .connection_point);
             },
+            [&](YaConnectionPoint::Notify& request)
+                -> YaConnectionPoint::Notify::Response {
+                return object_instances[request.instance_id]
+                    .connection_point->notify(&request.message);
+            },
             [&](YaEditController::SetComponentState& request)
                 -> YaEditController::SetComponentState::Response {
                 return object_instances[request.instance_id]