Avoid throwing away native module calls (#248)

The current implementation of `JsiDispatchEvent` calls directly into
`callFunctionReturnFlushedQueue` to trigger a call into the JS code.
Unfortunately, this call returns an array which is a list of native
module calls which should be made. But this code is not able to call
those native modules since that code is not exposed. So instead, there
are just a set of native module calls which never get called.

This PR replaces the call to `callFunctionReturnFlushedQueue` with a
call directly into the `RCTEventEmitter.receiveEvent` function, which
will not do the flush.

The flush will be done by the `ExecuteJsi` function, which will
correctly flush and call the native modules returned.

Fixes #247

###### Microsoft Reviewers: [Open in
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Author: acoates-ms

change/react-native-xaml-2081187e-e006-4295-a34d-3985fb4ebe93.json

@@ -0,0 +1,7 @@
+{
+  "type": "patch",
+  "comment": "Avoid throwing away native module calls.",
+  "packageName": "react-native-xaml",
+  "email": "30809111+acoates-ms@users.noreply.github.com",
+  "dependentChangeType": "patch"
+}

package/Codegen/TypeEvents.cs

@@ -76,7 +76,7 @@ public virtual string TransformText()
                     "atchTheEvent(const EventAttachInfo& eai, const winrt::Windows::Foundation::IInsp" +
                     "ectable& sender, const T& args) {\r\n  auto senderAsFE = sender.try_as<FrameworkEl" +
                     "ement>();\r\n  auto wEN = winrt::to_hstring(eai.jsEventName);\r\n  if (eai.xamlMetad" +
-                    "ata.m_callFunctionReturnFlushedQueue.has_value()) {\r\n    const auto tag = XamlMe" +
+                    "ata.m_receiveEvent.has_value()) {\r\n    const auto tag = XamlMe" +
                     "tadata::TagFromElement(eai.obj.as<xaml::DependencyObject>());\r\n    ExecuteJsi(ea" +
                     "i.context, [metadata = eai.xamlMetadata.shared_from_this(), tag, senderAsFE, arg" +
                     "s, eventName = eai.jsEventName](facebook::jsi::Runtime& rt) {\r\n      auto objSen" +

package/Codegen/TypeEvents.tt

@@ -34,7 +34,7 @@ template<typename T>
 __declspec(noinline) void DispatchTheEvent(const EventAttachInfo& eai, const winrt::Windows::Foundation::IInspectable& sender, const T& args) {
   auto senderAsFE = sender.try_as<FrameworkElement>();
   auto wEN = winrt::to_hstring(eai.jsEventName);
-  if (eai.xamlMetadata.m_callFunctionReturnFlushedQueue.has_value()) {
+  if (eai.xamlMetadata.m_receiveEvent.has_value()) {
     const auto tag = XamlMetadata::TagFromElement(eai.obj.as<xaml::DependencyObject>());
     ExecuteJsi(eai.context, [metadata = eai.xamlMetadata.shared_from_this(), tag, senderAsFE, args, eventName = eai.jsEventName](facebook::jsi::Runtime& rt) {
       auto objSender = std::make_shared<XamlObject>(senderAsFE, metadata);

package/windows/ReactNativeXaml/Codegen/TypeEvents.g.h

@@ -34,7 +34,7 @@ template<typename T>
 __declspec(noinline) void DispatchTheEvent(const EventAttachInfo& eai, const winrt::Windows::Foundation::IInspectable& sender, const T& args) {
   auto senderAsFE = sender.try_as<FrameworkElement>();
   auto wEN = winrt::to_hstring(eai.jsEventName);
-  if (eai.xamlMetadata.m_callFunctionReturnFlushedQueue.has_value()) {
+  if (eai.xamlMetadata.m_receiveEvent.has_value()) {
     const auto tag = XamlMetadata::TagFromElement(eai.obj.as<xaml::DependencyObject>());
     ExecuteJsi(eai.context, [metadata = eai.xamlMetadata.shared_from_this(), tag, senderAsFE, args, eventName = eai.jsEventName](facebook::jsi::Runtime& rt) {
       auto objSender = std::make_shared<XamlObject>(senderAsFE, metadata);

package/windows/ReactNativeXaml/XamlMetadata.cpp

@@ -40,8 +40,9 @@ void XamlMetadata::SetupEventDispatcher(const IReactContext& reactContext) {
       auto batchedBridge = rt.global().getProperty(rt, "__fbBatchedBridge");
       if (!batchedBridge.isUndefined() && batchedBridge.isObject()) {
         if (auto vm = shared.get()) {
-          vm->m_callFunctionReturnFlushedQueue = batchedBridge.asObject(rt).getPropertyAsFunction(
-            rt, "callFunctionReturnFlushedQueue");
+           auto getCallableModule = batchedBridge.asObject(rt).getPropertyAsFunction(rt, "getCallableModule");
+           vm->m_eventEmitter = getCallableModule.callWithThis(rt, batchedBridge.asObject(rt), "RCTEventEmitter").asObject(rt);
+           vm->m_receiveEvent = vm->m_eventEmitter->getPropertyAsFunction(rt, "receiveEvent");
         }
       }
     });
@@ -332,12 +333,7 @@ const EventInfo* XamlMetadata::AttachEvent(const winrt::Microsoft::ReactNative::
 }
 
 void XamlMetadata::JsiDispatchEvent(jsi::Runtime& rt, int64_t viewTag, std::string&& eventName, std::shared_ptr<facebook::jsi::Object>& eventData) const noexcept {
-  auto params = jsi::Array(rt, 3);
-  params.setValueAtIndex(rt, 0, static_cast<int>(viewTag));
-  params.setValueAtIndex(rt, 1, eventName);
-  params.setValueAtIndex(rt, 2, *eventData.get());
-
-  m_callFunctionReturnFlushedQueue->call(rt, "RCTEventEmitter", "receiveEvent", params);
+  m_receiveEvent->callWithThis(rt, *m_eventEmitter,  static_cast<int>(viewTag), std::move(eventName), *eventData.get());
 }
 
 

package/windows/ReactNativeXaml/XamlMetadata.h

@@ -235,7 +235,8 @@ struct XamlMetadata : std::enable_shared_from_this<XamlMetadata> {
   void PopulateCommands(const winrt::Windows::Foundation::Collections::IVector<winrt::hstring>& commands) const;
 
   void JsiDispatchEvent(facebook::jsi::Runtime& rt, int64_t viewTag, std::string&& eventName, std::shared_ptr<facebook::jsi::Object>& eventData) const noexcept;
-  std::optional<facebook::jsi::Function> m_callFunctionReturnFlushedQueue;
+  std::optional<facebook::jsi::Function> m_receiveEvent;
+  std::optional<facebook::jsi::Object> m_eventEmitter;
   winrt::Microsoft::ReactNative::IReactDispatcher UIDispatcher() const { return m_reactContext.UIDispatcher(); }
   xaml::DependencyObject ElementFromTag(int64_t tag) const { return winrt::Microsoft::ReactNative::XamlUIService::FromContext(m_reactContext).ElementFromReactTag(tag); }
   static int64_t TagFromElement(xaml::DependencyObject const& element);