Partially implement IConnectionPoint::connect()

This now works for direct connections, which is probably how most hosts
will use this.

README.md

@@ -17,7 +17,7 @@ incomplete list of things that still have to be done before this can be used:
 
 - Interfaces left to implement:
   - `YaHostApplicationHostImpl::createComponent()`
-  - `IConnectionPoint` to supplement `IComponent`
+  - The other parts of `IConnectionPoint`, including support for host provided proxies
   - Finish implementing `IEditController{,2}`
   - All other mandatory interfaces
   - All other optional interfaces

src/common/logging/vst3.cpp

@@ -270,6 +270,15 @@ void Vst3Logger::log_request(bool is_host_vst,
     });
 }
 
+void Vst3Logger::log_request(bool is_host_vst,
+                             const YaConnectionPoint::Connect& request) {
+    log_request_base(is_host_vst, [&](auto& message) {
+        message << request.instance_id
+                << ": IConnectionPoint::connect(other = <IConnectionPoint* #"
+                << request.other_instance_id << ">)";
+    });
+}
+
 void Vst3Logger::log_request(
     bool is_host_vst,
     const YaEditController2::SetComponentState& request) {

src/common/logging/vst3.h

@@ -79,6 +79,7 @@ class Vst3Logger {
     void log_request(bool is_host_vst, const YaComponent::GetRoutingInfo&);
     void log_request(bool is_host_vst, const YaComponent::ActivateBus&);
     void log_request(bool is_host_vst, const YaComponent::SetActive&);
+    void log_request(bool is_host_vst, const YaConnectionPoint::Connect&);
     void log_request(bool is_host_vst,
                      const YaEditController2::SetComponentState&);
     void log_request(bool is_host_vst,

src/common/serialization/vst3.h

@@ -75,6 +75,7 @@ using ControlRequest = std::variant<Vst3PluginProxy::Construct,
                                     YaComponent::GetRoutingInfo,
                                     YaComponent::ActivateBus,
                                     YaComponent::SetActive,
+                                    YaConnectionPoint::Connect,
                                     YaEditController2::SetComponentState,
                                     YaEditController2::GetParameterCount,
                                     YaEditController2::GetParameterInfo,

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

@@ -67,6 +67,29 @@ class YaConnectionPoint : public Steinberg::Vst::IConnectionPoint {
 
     inline bool supported() const { return arguments.supported; }
 
+    /**
+     * Message to pass through a call to
+     * `IConnectionPoint::connect(other_instance_id)` to the Wine plugin host.
+     */
+    struct Connect {
+        using Response = UniversalTResult;
+
+        native_size_t instance_id;
+
+        /**
+         * The other object this object should be connected to. When connecting
+         * two `Vst3PluginProxy` objects, we can directly connect the underlying
+         * objects on the Wine side.
+         */
+        native_size_t other_instance_id;
+
+        template <typename S>
+        void serialize(S& s) {
+            s.value8b(instance_id);
+            s.value8b(other_instance_id);
+        }
+    };
+
     virtual tresult PLUGIN_API connect(IConnectionPoint* other) override = 0;
     virtual tresult PLUGIN_API disconnect(IConnectionPoint* other) override = 0;
     virtual tresult PLUGIN_API

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

@@ -193,13 +193,9 @@ tresult PLUGIN_API Vst3PluginProxyImpl::connect(IConnectionPoint* other) {
     // identify the other object by its instance IDs and then connect the
     // objects in the Wine plugin host directly
     if (auto other_proxy = dynamic_cast<Vst3PluginProxy*>(other)) {
-        // TODO: Remove debug
-        bridge.logger.log("Host is trying to connect us with instance " +
-                          std::to_string(other_proxy->instance_id()));
-
-        // TODO: Implement
-        bridge.logger.log("TODO IConnectionPoint::connect()");
-        return Steinberg::kNotImplemented;
+        return bridge.send_message(YaConnectionPoint::Connect{
+            .instance_id = arguments.instance_id,
+            .other_instance_id = other_proxy->instance_id()});
     } else {
         // TODO: Add support for `ConnectionProxy` and similar objects
         bridge.logger.log(

src/wine-host/bridges/vst3.cpp

@@ -32,6 +32,7 @@ InstanceInterfaces::InstanceInterfaces(
     : object(object),
       audio_processor(object),
       component(object),
+      connection_point(object),
       edit_controller(object),
       plugin_base(object) {}
 
@@ -250,6 +251,16 @@ void Vst3Bridge::run() {
                 return object_instances[request.instance_id]
                     .component->setActive(request.state);
             },
+            [&](const YaConnectionPoint::Connect& request)
+                -> YaConnectionPoint::Connect::Response {
+                // We can directly connect the underlying objects
+                // TODO: Add support for connecting objects through a proxy
+                //       object provided by the host
+                return object_instances[request.instance_id]
+                    .connection_point->connect(
+                        object_instances[request.other_instance_id]
+                            .connection_point);
+            },
             [&](YaEditController2::SetComponentState& request)
                 -> YaEditController2::SetComponentState::Response {
                 return object_instances[request.instance_id]

src/wine-host/bridges/vst3.h

@@ -54,6 +54,7 @@ struct InstanceInterfaces {
 
     Steinberg::FUnknownPtr<Steinberg::Vst::IAudioProcessor> audio_processor;
     Steinberg::FUnknownPtr<Steinberg::Vst::IComponent> component;
+    Steinberg::FUnknownPtr<Steinberg::Vst::IConnectionPoint> connection_point;
     Steinberg::FUnknownPtr<Steinberg::Vst::IEditController> edit_controller;
     Steinberg::FUnknownPtr<Steinberg::IPluginBase> plugin_base;
 };