Implement IComponent::getState()

With this the basic IComponent interface is fully implemented. Next will
be `IAudioProcessor` and `IConnectionPoint` as additions to IComponent.
We'll use the same `known_iids` mechanism as used in the plugin factory.

README.md

@@ -17,11 +17,13 @@ imcomplete list of things that still have to be done before this can be used:
 
 - Left to implement:
   - `YaHostApplicationHostImpl::createComponent`.
-  - The rest of `IComponent`'s functions
+  - `IAudioProcessor` and `IConnectionPoint` to supplement `IComponent`
+  - `IEditController{,2}`
   - All other mandatory interfaces
   - All other optional interfaces
 - Fully implemented:
   - `GetPluginFactory()` and `IPluginFactory{,2,3}`
+  - `IComponent`
 - Update the GitHub Actions workflows.
 - Update yabridgectl to handle buth VST2 and VST3 plugins.
 - Update all documentation to refer to VST2 and VST3 support separately, and

src/common/logging/vst3.cpp

@@ -142,6 +142,14 @@ void Vst3Logger::log_request(bool is_host_vst,
     });
 }
 
+void Vst3Logger::log_request(bool is_host_vst,
+                             const YaComponent::GetState& request) {
+    log_request_base(is_host_vst, [&](auto& message) {
+        message << "<IComponent* #" << request.instance_id
+                << ">::getState(state = <IBStream*>)";
+    });
+}
+
 void Vst3Logger::log_request(bool is_host_vst,
                              const YaPluginFactory::Construct&) {
     log_request_base(is_host_vst,
@@ -206,6 +214,17 @@ void Vst3Logger::log_response(
     });
 }
 
+void Vst3Logger::log_response(bool is_host_vst,
+                              const YaComponent::GetStateResponse& response) {
+    log_response_base(is_host_vst, [&](auto& message) {
+        message << response.result.string();
+        if (response.result.native() == Steinberg::kResultOk) {
+            message << ", <IBStream* containing "
+                    << response.updated_state.size() << " bytes>";
+        }
+    });
+}
+
 void Vst3Logger::log_response(bool is_host_vst,
                               const YaPluginFactory::ConstructArgs& args) {
     log_response_base(is_host_vst, [&](auto& message) {

src/common/logging/vst3.h

@@ -67,6 +67,7 @@ class Vst3Logger {
     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 YaComponent::SetState&);
+    void log_request(bool is_host_vst, const YaComponent::GetState&);
     void log_request(bool is_host_vst, const YaPluginFactory::Construct&);
     void log_request(bool is_host_vst, const YaPluginFactory::SetHostContext&);
     void log_request(bool is_host_vst, const WantsConfiguration&);
@@ -78,6 +79,7 @@ class Vst3Logger {
     void log_response(bool is_host_vst, const YaComponent::GetBusInfoResponse&);
     void log_response(bool is_host_vst,
                       const YaComponent::GetRoutingInfoResponse&);
+    void log_response(bool is_host_vst, const YaComponent::GetStateResponse&);
     void log_response(bool is_host_vst, const YaPluginFactory::ConstructArgs&);
     void log_response(bool is_host_vst, const Configuration&);
 

src/common/serialization/vst3.h

@@ -68,6 +68,7 @@ using ControlRequest = std::variant<YaComponent::Construct,
                                     YaComponent::ActivateBus,
                                     YaComponent::SetActive,
                                     YaComponent::SetState,
+                                    YaComponent::GetState,
                                     YaPluginFactory::Construct,
                                     YaPluginFactory::SetHostContext>;
 

src/common/serialization/vst3/base.cpp

@@ -175,15 +175,15 @@ tresult PLUGIN_API VectorStream::queryInterface(Steinberg::FIDString _iid,
     return Steinberg::kNoInterface;
 }
 
-tresult VectorStream::write_back(Steinberg::IBStream* stream) {
+tresult VectorStream::write_back(Steinberg::IBStream* stream) const {
     if (!stream) {
         return Steinberg::kInvalidArgument;
     }
 
     int32 num_bytes_written;
     assert(stream->seek(0, kIBSeekSet) == Steinberg::kResultOk);
-    assert(stream->write(buffer.data(), buffer.size(), &num_bytes_written) ==
-           Steinberg::kResultOk);
+    assert(stream->write(const_cast<uint8_t*>(buffer.data()), buffer.size(),
+                         &num_bytes_written) == Steinberg::kResultOk);
 
     assert(num_bytes_written == 0 ||
            static_cast<size_t>(num_bytes_written) == buffer.size());

src/common/serialization/vst3/base.h

@@ -140,7 +140,7 @@ class VectorStream : public Steinberg::IBStream,
      * Write the vector buffer back to an IBStream. After writing the seek
      * position will be left at the end of the stream.
      */
-    tresult write_back(Steinberg::IBStream* stream);
+    tresult write_back(Steinberg::IBStream* stream) const;
 
     /**
      * Return the buffer's, used in the logging messages.

src/common/serialization/vst3/component.h

@@ -371,6 +371,37 @@ class YaComponent : public Steinberg::Vst::IComponent {
 
     virtual tresult PLUGIN_API
     setState(Steinberg::IBStream* state) override = 0;
+
+    /**
+     * The response code and written state for a call to
+     * `IComponent::getState(state)`.
+     */
+    struct GetStateResponse {
+        UniversalTResult result;
+        VectorStream updated_state;
+
+        template <typename S>
+        void serialize(S& s) {
+            s.object(result);
+            s.object(updated_state);
+        }
+    };
+
+    /**
+     * Message to pass through a call to `IComponent::getState(state)` to the
+     * Wine plugin host.
+     */
+    struct GetState {
+        using Response = GetStateResponse;
+
+        native_size_t instance_id;
+
+        template <typename S>
+        void serialize(S& s) {
+            s.value8b(instance_id);
+        }
+    };
+
     virtual tresult PLUGIN_API
     getState(Steinberg::IBStream* state) override = 0;
 

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

@@ -148,7 +148,10 @@ tresult PLUGIN_API YaComponentPluginImpl::setState(Steinberg::IBStream* state) {
 }
 
 tresult PLUGIN_API YaComponentPluginImpl::getState(Steinberg::IBStream* state) {
-    // TODO: Implement
-    bridge.logger.log("TODO: IComponent::getState()");
-    return Steinberg::kNotImplemented;
+    const GetStateResponse response = bridge.send_message(
+        YaComponent::GetState{.instance_id = arguments.instance_id});
+
+    assert(response.updated_state.write_back(state) == Steinberg::kResultOk);
+
+    return response.result.native();
 }

src/wine-host/bridges/vst3.cpp

@@ -158,6 +158,15 @@ void Vst3Bridge::run() {
                 return component_instances[request.instance_id]
                     .component->setState(&request.state);
             },
+            [&](YaComponent::GetState& request)
+                -> YaComponent::GetState::Response {
+                VectorStream stream;
+                const tresult result = component_instances[request.instance_id]
+                                           .component->getState(&stream);
+
+                return YaComponent::GetStateResponse{
+                    .result = result, .updated_state = std::move(stream)};
+            },
             [&](const YaPluginFactory::Construct&)
                 -> YaPluginFactory::Construct::Response {
                 return YaPluginFactory::ConstructArgs(