Initialize Xaml on demand only for module authors

change/react-native-windows-73f0d63e-63d7-4322-b402-83e1c0c092e8.json

@@ -0,0 +1,7 @@
+{
+  "type": "none",
+  "comment": "Initialize Xaml on demand only for module authors",
+  "packageName": "react-native-windows",
+  "email": "[email protected]",
+  "dependentChangeType": "none"
+}

vnext/Microsoft.ReactNative/Fabric/Composition/ReactCompositionViewComponentBuilder.cpp

@@ -227,6 +227,14 @@ void ReactCompositionViewComponentBuilder::SetUnmountChildComponentViewHandler(
   m_unmountChildComponentViewHandler = impl;
 }
 
+bool ReactCompositionViewComponentBuilder::XamlSupport() const noexcept {
+  return m_xamlSupport;
+}
+
+void ReactCompositionViewComponentBuilder::XamlSupport(bool isRequired) noexcept {
+  m_xamlSupport = isRequired;
+}
+
 const UnmountChildComponentViewDelegate &ReactCompositionViewComponentBuilder::UnmountChildComponentViewHandler()
     const noexcept {
   return m_unmountChildComponentViewHandler;

vnext/Microsoft.ReactNative/Fabric/Composition/ReactCompositionViewComponentBuilder.h

@@ -39,6 +39,8 @@ struct ReactCompositionViewComponentBuilder
   void SetUpdateEventEmitterHandler(UpdateEventEmitterDelegate impl) noexcept;
   void SetMountChildComponentViewHandler(MountChildComponentViewDelegate impl) noexcept;
   void SetUnmountChildComponentViewHandler(UnmountChildComponentViewDelegate impl) noexcept;
+  bool XamlSupport() const noexcept;
+  void XamlSupport(bool isRequired) noexcept;
 
  public: // Composition::IReactCompositionViewComponentBuilder
   void SetViewComponentViewInitializer(const ViewComponentViewInitializer &initializer) noexcept;
@@ -108,6 +110,7 @@ struct ReactCompositionViewComponentBuilder
   winrt::Microsoft::ReactNative::Composition::Experimental::IVisualToMountChildrenIntoDelegate
       m_visualToMountChildrenIntoHandler;
   UpdateLayoutMetricsDelegate m_updateLayoutMetricsHandler;
+  bool m_xamlSupport{false};
 };
 
 } // namespace winrt::Microsoft::ReactNative::Composition

vnext/Microsoft.ReactNative/Fabric/WindowsComponentDescriptorRegistry.cpp

@@ -54,6 +54,14 @@ bool WindowsComponentDescriptorRegistry::hasComponentProvider(const std::string
   return std::find(m_componentNames.begin(), m_componentNames.end(), name) != m_componentNames.end();
 }
 
+bool WindowsComponentDescriptorRegistry::isXamlSupportRequired() const noexcept {
+  return std::any_of(m_builderByName.cbegin(), m_builderByName.cend(), [](const auto &pair) -> bool {
+    return winrt::get_self<winrt::Microsoft::ReactNative::Composition::ReactCompositionViewComponentBuilder>(
+               pair.second)
+        ->XamlSupport();
+  });
+}
+
 void WindowsComponentDescriptorRegistry::Add(
     winrt::hstring componentName,
     winrt::Microsoft::ReactNative::ReactViewComponentProvider const &provider) noexcept {

vnext/Microsoft.ReactNative/Fabric/WindowsComponentDescriptorRegistry.h

@@ -34,6 +34,9 @@ struct WindowsComponentDescriptorRegistry {
 
   bool hasComponentProvider(const std::string &name) noexcept;
 
+  // Returns true if any component requested for XAML support.
+  bool isXamlSupportRequired() const noexcept;
+
  private:
   void add(const facebook::react::ComponentDescriptorProvider &provider) noexcept;
 

vnext/Microsoft.ReactNative/IReactViewComponentBuilder.idl

@@ -124,6 +124,7 @@ namespace Microsoft.ReactNative
     void SetUpdateEventEmitterHandler(UpdateEventEmitterDelegate impl);
     void SetMountChildComponentViewHandler(MountChildComponentViewDelegate impl);
     void SetUnmountChildComponentViewHandler(UnmountChildComponentViewDelegate impl);
+    Boolean XamlSupport { get; set; };
   };
 
   // [exclusiveto(ShadowNode)]

vnext/Microsoft.ReactNative/Microsoft.ReactNative.vcxproj

@@ -124,6 +124,7 @@
         DISABLE_XAML_GENERATED_MAIN;
         REACTWINDOWS_BUILD;
         RN_PLATFORM=windows;
+        RNW_XAML_ISLAND;
         NOMINMAX;
         FOLLY_CFG_NO_COROUTINES;
         FOLLY_NO_CONFIG;

vnext/Microsoft.ReactNative/ReactNativeHost.cpp

@@ -13,6 +13,9 @@
 #include <winrt/Windows.Foundation.Collections.h>
 #include "IReactContext.h"
 #include "ReactInstanceSettings.h"
+#ifdef RNW_XAML_ISLAND
+#include "XamlApplication.h"
+#endif // RNW_XAML_ISLAND
 
 #include <Fabric/Composition/Modal/WindowsModalHostViewComponentView.h>
 #include <Fabric/WindowsComponentDescriptorRegistry.h>
@@ -102,6 +105,12 @@ IAsyncAction ReactNativeHost::ReloadInstance() noexcept {
     }
   }
 
+#ifdef RNW_XAML_ISLAND
+  if (componentregistry->isXamlSupportRequired()) {
+    winrt::Microsoft::ReactNative::Xaml::implementation::XamlApplication::EnsureCreated();
+  }
+#endif // RNW_XAML_ISLAND
+
   ReactPropertyBag(m_instanceSettings.Properties()).Set(ReactNativeHostProperty(), get_weak());
 
   Mso::React::ReactOptions reactOptions{};

vnext/Shared/Shared.vcxitems

@@ -139,11 +139,6 @@
       <ExcludedFromBuild Condition="'$(UseFabric)' != 'true' OR '$(SupportWinUI3Islands)' != 'true'">true</ExcludedFromBuild>
       <DependentUpon>$(ReactNativeWindowsDir)Microsoft.ReactNative\XamlApplication.idl</DependentUpon>
       <SubType>Code</SubType>
-    </ClCompile>
-      <ClCompile Include="$(MSBuildThisFileDirectory)..\Microsoft.ReactNative\XamlHost.cpp">
-      <ExcludedFromBuild Condition="'$(UseFabric)' != 'true' OR '$(SupportWinUI3Islands)' != 'true'">true</ExcludedFromBuild>
-      <DependentUpon>$(ReactNativeWindowsDir)Microsoft.ReactNative\XamlApplication.idl</DependentUpon>
-      <SubType>Code</SubType>
     </ClCompile>
     <ClCompile Include="$(MSBuildThisFileDirectory)BaseFileReaderResource.cpp" />
     <ClCompile Include="$(MSBuildThisFileDirectory)BaseScriptStoreImpl.cpp" />
@@ -248,11 +243,6 @@
       <ExcludedFromBuild Condition="'$(UseFabric)' != 'true' OR '$(SupportWinUI3Islands)' != 'true'">true</ExcludedFromBuild>
       <DependentUpon>$(MSBuildThisFileDirectory)..\Microsoft.ReactNative\XamlApplication.idl</DependentUpon>
       <SubType>Code</SubType>
-    </ClInclude>
-      <ClInclude Include="$(MSBuildThisFileDirectory)..\Microsoft.ReactNative\XamlHost.h">
-      <ExcludedFromBuild Condition="'$(UseFabric)' != 'true' OR '$(SupportWinUI3Islands)' != 'true'">true</ExcludedFromBuild>
-      <DependentUpon>$(MSBuildThisFileDirectory)..\Microsoft.ReactNative\XamlApplication.idl</DependentUpon>
-      <SubType>Code</SubType>
     </ClInclude>
     <ClCompile Include="$(MSBuildThisFileDirectory)..\Microsoft.ReactNative\DynamicReader.cpp">
       <DependentUpon>$(MSBuildThisFileDirectory)..\Microsoft.ReactNative\IJSValueReader.idl</DependentUpon>
@@ -612,7 +602,6 @@
     <Midl Condition="'$(UseFabric)' == 'true' OR '$(IncludeFabricInterface)' == 'true'" Include="$(ReactNativeWindowsDir)Microsoft.ReactNative\ViewProps.idl" />
     <Midl Condition="'$(UseFabric)' == 'true' OR '$(IncludeFabricInterface)' == 'true'" Include="$(ReactNativeWindowsDir)Microsoft.ReactNative\ReactNativeAppBuilder.idl" />
     <Midl Condition="('$(UseFabric)' == 'true' OR '$(IncludeFabricInterface)' == 'true') AND '$(SupportWinUI3Islands)' == 'true'" Include="$(ReactNativeWindowsDir)Microsoft.ReactNative\XamlApplication.idl" />
-    <Midl Condition="('$(UseFabric)' == 'true' OR '$(IncludeFabricInterface)' == 'true') AND '$(SupportWinUI3Islands)' == 'true'" Include="$(ReactNativeWindowsDir)Microsoft.ReactNative\IXamlProvider.idl" />
   </ItemGroup>
   <ItemGroup>
     <ClInclude Include="$(NodeApiJsiDir)src\ApiLoaders\HermesApi.h" />

vnext/overrides.json

@@ -694,18 +694,6 @@
       "file": "src-win/src/private/specs_DEPRECATED/modules/NativePlatformConstantsWindows.js",
       "baseFile": "packages/react-native/src/private/specs_DEPRECATED/modules/NativePlatformConstantsAndroid.js",
       "baseHash": "365c5df75b38b129d364af3f6700cb206ce5bd2a"
-    },
-    {
-      "type": "platform",
-      "file": "src-win/Libraries/Components/Xaml/XamlHost.d.ts"
-    },
-    {
-      "type": "platform",
-      "file": "src-win/Libraries/Components/Xaml/XamlHost.windows.js"
-    },
-    {
-      "type": "platform",
-      "file": "src-win/src/private/specs_DEPRECATED/components/Xaml/XamlHostNativeComponent.js"
     }
   ]
-}
+}

vnext/src-win/index.windows.js

@@ -372,9 +372,6 @@ module.exports = {
   get AppTheme() {
     return require('./Libraries/AppTheme/AppTheme').AppTheme;
   },
-  get XamlHost() {
-    return require('./Libraries/Components/Xaml/XamlHost').default;
-  },
 } as ReactNativePublicAPI;
 
 if (__DEV__) {

vnext/src-win/index.windows.js.flow

@@ -469,7 +469,6 @@ export {HandledEventPhase } from './Libraries/Components/View/ViewPropTypes'
 
 export {default as ViewWindows} from './Libraries/Components/View/View';
 export {AppTheme} from './Libraries/AppTheme/AppTheme';
-export {default as XamlHost} from './Libraries/Components/Xaml/XamlHost';
 // End Windows Specific exports
 
 // #endregion