C++ 20: Move vnext to C++ 20 and C++ 20 coroutines

change/react-native-windows-dce01c53-5395-463d-bbfd-9162cd9f309d.json

@@ -0,0 +1,7 @@
+{
+  "type": "prerelease",
+  "comment": "C++ 20: Move vnext to C++ 20 and C++ 20 coroutines",
+  "packageName": "react-native-windows",
+  "email": "ngerlem@fb.com",
+  "dependentChangeType": "patch"
+}

vnext/Desktop.UnitTests/React.Windows.Desktop.UnitTests.vcxproj

@@ -69,7 +69,6 @@
         $(VCInstallDir)UnitTest\include;
         %(AdditionalIncludeDirectories)
       </AdditionalIncludeDirectories>
-      <AdditionalOptions>%(AdditionalOptions) /await</AdditionalOptions>
     </ClCompile>
     <Link>
       <!--

vnext/Microsoft.ReactNative.Cxx.UnitTests/Microsoft.ReactNative.Cxx.UnitTests.vcxproj

@@ -65,7 +65,7 @@
       <PreprocessorDefinitions>_CONSOLE;MSO_MOTIFCPP;%(PreprocessorDefinitions)</PreprocessorDefinitions>
       <WarningLevel>Level4</WarningLevel>
       <AdditionalIncludeDirectories>$(MSBuildThisFileDirectory);%(AdditionalIncludeDirectories)</AdditionalIncludeDirectories>
-      <AdditionalOptions>/await %(AdditionalOptions) /bigobj</AdditionalOptions>
+      <AdditionalOptions>%(AdditionalOptions) /bigobj</AdditionalOptions>
       <ConformanceMode>true</ConformanceMode>
       <CallingConvention>Cdecl</CallingConvention>
     </ClCompile>
@@ -165,4 +165,4 @@
     <PackageReference Include="$(V8PackageName)" Version="$(V8Version)" Condition="'$(UseV8)' == 'true'" />
   </ItemGroup>
   <Import Project="$(VCTargetsPath)\Microsoft.Cpp.targets" />
-</Project>
+</Project>

vnext/Microsoft.ReactNative.IntegrationTests/Microsoft.ReactNative.IntegrationTests.vcxproj

@@ -64,7 +64,7 @@
       <PreprocessorDefinitions>_CONSOLE;MSO_MOTIFCPP;FOLLY_CFG_NO_COROUTINES;FOLLY_NO_CONFIG;%(PreprocessorDefinitions)</PreprocessorDefinitions>
       <WarningLevel>Level4</WarningLevel>
       <AdditionalIncludeDirectories>$(MSBuildThisFileDirectory);%(AdditionalIncludeDirectories)</AdditionalIncludeDirectories>
-      <AdditionalOptions>/await %(AdditionalOptions) /bigobj</AdditionalOptions>
+      <AdditionalOptions>%(AdditionalOptions) /bigobj</AdditionalOptions>
       <ConformanceMode>true</ConformanceMode>
       <CallingConvention>Cdecl</CallingConvention>
       <!-- We need RuntimeTypeInfo for JSI tests -->

vnext/Microsoft.ReactNative/Microsoft.ReactNative.vcxproj

@@ -95,7 +95,7 @@
       <PrecompiledHeaderOutputFile>$(IntDir)pch.pch</PrecompiledHeaderOutputFile>
       <ForcedIncludeFiles>pch.h</ForcedIncludeFiles>
       <WarningLevel>Level4</WarningLevel>
-      <AdditionalOptions>/await %(AdditionalOptions) /bigobj /ZH:SHA_256</AdditionalOptions>
+      <AdditionalOptions>%(AdditionalOptions) /bigobj /ZH:SHA_256</AdditionalOptions>
       <AdditionalIncludeDirectories>
         $(FmtDir)\include;
         $(ReactNativeWindowsDir)Microsoft.ReactNative;

vnext/Microsoft.ReactNative/Utils/LocalBundleReader.cpp

@@ -53,7 +53,8 @@ std::string GetBundleFromEmbeddedResource(const winrt::Windows::Foundation::Uri
   return std::string(start, start + size);
 }
 
-std::future<std::string> LocalBundleReader::LoadBundleAsync(const std::wstring bundleUri) {
+winrt::Windows::Foundation::IAsyncOperation<winrt::hstring> LocalBundleReader::LoadBundleAsync(
+    const std::wstring bundleUri) {
   co_await winrt::resume_background();
 
   winrt::Windows::Storage::StorageFile file{nullptr};
@@ -65,7 +66,7 @@ std::future<std::string> LocalBundleReader::LoadBundleAsync(const std::wstring b
     file = co_await winrt::Windows::Storage::StorageFile::GetFileFromApplicationUriAsync(uri);
   } else if (bundleUri._Starts_with(L"resource://")) {
     winrt::Windows::Foundation::Uri uri(bundleUri);
-    co_return GetBundleFromEmbeddedResource(uri);
+    co_return winrt::to_hstring(GetBundleFromEmbeddedResource(uri));
   } else {
     file = co_await winrt::Windows::Storage::StorageFile::GetFileFromPathAsync(bundleUri);
   }
@@ -86,10 +87,10 @@ std::future<std::string> LocalBundleReader::LoadBundleAsync(const std::wstring b
       reinterpret_cast<uint8_t *>(&script[0]), reinterpret_cast<uint8_t *>(&script[script.length()])});
   dataReader.Close();
 
-  co_return script;
+  co_return winrt::to_hstring(script);
 }
 
-std::string LocalBundleReader::LoadBundle(const std::wstring &bundlePath) {
+winrt::hstring LocalBundleReader::LoadBundle(const std::wstring &bundlePath) {
   return LoadBundleAsync(bundlePath).get();
 }
 
@@ -113,7 +114,7 @@ size_t StorageFileBigString::size() const {
 
 void StorageFileBigString::ensure() const {
   if (m_string.empty()) {
-    m_string = m_futureBuffer.get();
+    m_string = winrt::to_string(m_futureBuffer.get());
   }
 }
 

vnext/Microsoft.ReactNative/Utils/LocalBundleReader.h

@@ -3,15 +3,15 @@
 
 #pragma once
 #include <cxxreact/JSBigString.h>
-#include <future>
+#include <winrt/Windows.Foundation.h>
 #include <string>
 
 namespace Microsoft::ReactNative {
 
 class LocalBundleReader {
  public:
-  static std::future<std::string> LoadBundleAsync(const std::wstring bundlePath);
-  static std::string LoadBundle(const std::wstring &bundlePath);
+  static winrt::Windows::Foundation::IAsyncOperation<winrt::hstring> LoadBundleAsync(const std::wstring bundleUri);
+  static winrt::hstring LoadBundle(const std::wstring &bundlePath);
 };
 
 class StorageFileBigString : public facebook::react::JSBigString {
@@ -24,7 +24,7 @@ class StorageFileBigString : public facebook::react::JSBigString {
   void ensure() const;
 
  private:
-  mutable std::future<std::string> m_futureBuffer;
+  mutable winrt::Windows::Foundation::IAsyncOperation<winrt::hstring> m_futureBuffer;
   mutable std::string m_string;
 };
 

vnext/Microsoft.ReactNative/Utils/UwpScriptStore.cpp

@@ -43,7 +43,8 @@ facebook::jsi::ScriptVersion_t UwpScriptStore::getScriptVersion(const std::strin
   return version;
 }
 
-std::future<facebook::jsi::ScriptVersion_t> UwpScriptStore::getScriptVersionAsync(const std::string &bundleUri) {
+winrt::Windows::Foundation::IAsyncOperation<facebook::jsi::ScriptVersion_t> UwpScriptStore::getScriptVersionAsync(
+    const std::string &bundleUri) {
   co_await winrt::resume_background();
 
   const winrt::hstring fileUrl(Microsoft::Common::Unicode::Utf8ToUtf16("ms-appx:///Bundle/" + bundleUri + ".bundle"));

vnext/Microsoft.ReactNative/Utils/UwpScriptStore.h

@@ -1,6 +1,6 @@
 #pragma once
 #include <JSI/ScriptStore.h>
-#include <future>
+#include <winrt/Windows.Foundation.h>
 
 namespace Microsoft::ReactNative {
 
@@ -16,7 +16,8 @@ class UwpScriptStore : public facebook::jsi::ScriptStore {
   static facebook::jsi::ScriptVersion_t GetFileVersion(const std::wstring &filePath);
 
  private:
-  std::future<facebook::jsi::ScriptVersion_t> getScriptVersionAsync(const std::string &bundleUri);
+  winrt::Windows::Foundation::IAsyncOperation<facebook::jsi::ScriptVersion_t> getScriptVersionAsync(
+      const std::string &bundleUri);
 };
 
 } // namespace Microsoft::ReactNative

vnext/Mso.UnitTests/Mso.UnitTests.vcxproj

@@ -62,7 +62,7 @@
       <PrecompiledHeaderOutputFile>$(IntDir)pch.pch</PrecompiledHeaderOutputFile>
       <PreprocessorDefinitions>_CONSOLE;MS_TARGET_WINDOWS;MSO_MOTIFCPP;%(PreprocessorDefinitions)</PreprocessorDefinitions>
       <WarningLevel>Level4</WarningLevel>
-      <AdditionalOptions>/await %(AdditionalOptions) /bigobj</AdditionalOptions>
+      <AdditionalOptions>%(AdditionalOptions) /bigobj</AdditionalOptions>
       <ConformanceMode>true</ConformanceMode>
       <CallingConvention>Cdecl</CallingConvention>
     </ClCompile>
@@ -148,4 +148,4 @@
     <PackageReference Include="Microsoft.Windows.CppWinRT" Version="$(CppWinRTVersion)" PrivateAssets="all" />
   </ItemGroup>
   <Import Project="$(VCTargetsPath)\Microsoft.Cpp.targets" />
-</Project>
+</Project>

vnext/PropertySheets/React.Cpp.props

@@ -152,4 +152,4 @@
     </Link>
   </ItemDefinitionGroup>
 
-</Project>
+</Project>

vnext/Shared/DevSupportManager.cpp

@@ -15,6 +15,7 @@
 #include "Utilities.h"
 
 #include <Utils/CppWinrtLessExceptions.h>
+#include <winrt/Windows.Foundation.Collections.h>
 #include <winrt/Windows.Foundation.h>
 #include <winrt/Windows.Storage.Streams.h>
 #include <winrt/Windows.Web.Http.Filters.h>
@@ -30,7 +31,6 @@
 #include <cxxreact/MessageQueueThread.h>
 #pragma warning(pop)
 
-#include <future>
 #include <mutex>
 
 #include <AppModel.h>
@@ -44,7 +44,9 @@ using namespace facebook::react;
 
 namespace Microsoft::ReactNative {
 
-std::future<std::pair<std::string, bool>> GetJavaScriptFromServerAsync(const std::string &url) {
+winrt::Windows::Foundation::IAsyncOperation<
+    winrt::Windows::Foundation::Collections::IKeyValuePair<winrt::hstring, bool>>
+GetJavaScriptFromServerAsync(const std::string &url) {
   winrt::Windows::Web::Http::Filters::HttpBaseProtocolFilter filter;
   filter.CacheControl().ReadBehavior(winrt::Windows::Web::Http::Filters::HttpCacheReadBehavior::NoCache);
   winrt::Windows::Web::Http::HttpClient httpClient(filter);
@@ -58,8 +60,9 @@ std::future<std::pair<std::string, bool>> GetJavaScriptFromServerAsync(const std
   try {
     winrt::Windows::Web::Http::HttpResponseMessage response = co_await asyncRequest;
   } catch (winrt::hresult_error const &e) {
-    co_return std::make_pair(
-        Microsoft::Common::Unicode::Utf16ToUtf8(e.message().c_str(), e.message().size()).c_str(), false);
+    co_return winrt::pair<winrt::hstring, bool>(
+        winrt::to_hstring(Microsoft::Common::Unicode::Utf16ToUtf8(e.message().c_str(), e.message().size()).c_str()),
+        false);
   }
 #else
   co_await lessthrow_await_adapter<winrt::Windows::Foundation::IAsyncOperationWithProgress<
@@ -74,7 +77,7 @@ std::future<std::pair<std::string, bool>> GetJavaScriptFromServerAsync(const std
     } else {
       error = fmt::format("Error 0x{:x} downloading {}.", static_cast<int>(asyncRequest.ErrorCode()), url);
     }
-    co_return std::make_pair(error, false);
+    co_return winrt::pair<winrt::hstring, bool>(winrt::to_hstring(error), false);
   }
 
   winrt::Windows::Web::Http::HttpResponseMessage response = asyncRequest.GetResults();
@@ -98,7 +101,7 @@ std::future<std::pair<std::string, bool>> GetJavaScriptFromServerAsync(const std
     result = fmt::format("HTTP Error {} downloading {}.", static_cast<int>(response.StatusCode()), url);
   }
 
-  co_return std::make_pair(std::move(result), response.IsSuccessStatusCode());
+  co_return winrt::pair<winrt::hstring, bool>(winrt::to_hstring(std::move(result)), response.IsSuccessStatusCode());
 }
 
 void LaunchDevTools(const facebook::react::DevSettings &settings) {
@@ -171,7 +174,8 @@ bool IsIgnorablePollHResult(HRESULT hr) {
   return hr == WININET_E_INVALID_SERVER_RESPONSE;
 }
 
-std::future<winrt::Windows::Web::Http::HttpStatusCode> PollForLiveReload(const std::string &url) {
+winrt::Windows::Foundation::IAsyncOperation<winrt::Windows::Web::Http::HttpStatusCode> PollForLiveReload(
+    const std::string url) {
   winrt::Windows::Web::Http::HttpClient httpClient;
   winrt::Windows::Foundation::Uri uri(Microsoft::Common::Unicode::Utf8ToUtf16(url));
   httpClient.DefaultRequestHeaders().Connection().TryParseAdd(L"keep-alive");
@@ -290,7 +294,8 @@ std::pair<std::string, bool> GetJavaScriptFromServer(
       inlineSourceMap,
       hermesBytecodeVersion);
   try {
-    return GetJavaScriptFromServerAsync(bundleUrl).get();
+    auto result = GetJavaScriptFromServerAsync(bundleUrl).get();
+    return std::make_pair(winrt::to_string(result.Key()), result.Value());
   } catch (winrt::hresult_error const &e) {
     return std::make_pair(
         "Error: " + Microsoft::Common::Unicode::Utf16ToUtf8(e.message().c_str(), e.message().size()), false);

vnext/Shared/DevSupportManager.h

@@ -7,6 +7,7 @@
 
 #include <DevServerHelper.h>
 
+#include <winrt/Windows.Foundation.Collections.h>
 #include <winrt/Windows.Networking.Sockets.h>
 #include <atomic>
 #include <functional>
@@ -22,6 +23,29 @@ struct DevSettings;
 }
 } // namespace facebook
 
+namespace winrt {
+
+template <typename K, typename V>
+struct pair_impl : implements<pair_impl<K, V>, Windows::Foundation::Collections::IKeyValuePair<K, V>> {
+  pair_impl(K k, V v) : m_k(k), m_v(v) {}
+  K Key() {
+    return m_k;
+  }
+  V Value() {
+    return m_v;
+  }
+
+ private:
+  K m_k;
+  V m_v;
+};
+
+template <typename K, typename V>
+Windows::Foundation::Collections::IKeyValuePair<K, V> pair(K key, V value) {
+  return make<pair_impl<K, V>>(key, value);
+}
+} // namespace winrt
+
 namespace Microsoft::ReactNative {
 
 std::pair<std::string, bool> GetJavaScriptFromServer(

vnext/Shared/HermesSamplingProfiler.cpp

@@ -5,7 +5,7 @@
 
 #include <hermes/hermes_api.h>
 #include <chrono>
-#include <future>
+#include <coroutine>
 
 #include "HermesRuntimeHolder.h"
 #include "HermesSamplingProfiler.h"
@@ -32,10 +32,8 @@ auto resume_in_dispatcher(const IReactDispatcher &dispatcher) noexcept {
 
     void await_resume() const noexcept {}
 
-    void await_suspend(std::experimental::coroutine_handle<> resume) noexcept {
-      callback_ = [context = resume.address()]() noexcept {
-        std::experimental::coroutine_handle<>::from_address(context)();
-      };
+    void await_suspend(std::coroutine_handle<> resume) noexcept {
+      callback_ = [context = resume.address()]() noexcept { std::coroutine_handle<>::from_address(context)(); };
       dispatcher_.Post(std::move(callback_));
     }
 
@@ -54,8 +52,7 @@ IAsyncOperation<winrt::hstring> getTraceFilePath() noexcept {
                  .count();
 
   os << hermesDataPath.c_str() << L"\\cpu_" << now << L".cpuprofile";
-  // TODO: Use C++ 20 `os.view()` to avoid a copy
-  co_return winrt::hstring(os.str());
+  co_return winrt::hstring(os.view());
 }
 
 } // namespace

vnext/Shared/Networking/WinRTWebSocketResource.cpp

@@ -20,6 +20,7 @@
 #include <winrt/Windows.Security.Cryptography.h>
 
 // Standard Library
+#include <coroutine>
 #include <sstream>
 
 using Microsoft::Common::Utilities::CheckedReinterpretCast;
@@ -67,10 +68,8 @@ auto resume_in_queue(const Mso::DispatchQueue &queue) noexcept {
 
     void await_resume() const noexcept {}
 
-    void await_suspend(std::experimental::coroutine_handle<> resume) noexcept {
-      m_callback = [context = resume.address()]() noexcept {
-        std::experimental::coroutine_handle<>::from_address(context)();
-      };
+    void await_suspend(std::coroutine_handle<> resume) noexcept {
+      m_callback = [context = resume.address()]() noexcept { std::coroutine_handle<>::from_address(context)(); };
       m_queue.Post(std::move(m_callback));
     }
 

vnext/Shared/Utils/CppWinrtLessExceptions.h

@@ -22,6 +22,7 @@
 #define SHARED_UTILS_CPPWINRTLESSEXCEPTIONS_H_
 
 #include <winrt/base.h>
+#include <coroutine>
 
 // #define DEFAULT_CPPWINRT_EXCEPTIONS
 #ifndef DEFAULT_CPPWINRT_EXCEPTIONS
@@ -35,15 +36,15 @@ struct lessthrow_await_adapter {
     return async.Status() == winrt::Windows::Foundation::AsyncStatus::Completed;
   }
 
-  void await_suspend(std::experimental::coroutine_handle<> handle) const {
+  void await_suspend(std::coroutine_handle<> handle) const {
     auto context = winrt::capture<winrt::impl::IContextCallback>(WINRT_IMPL_CoGetObjectContext);
 
     async.Completed([handle, context = std::move(context)](auto const &, winrt::Windows::Foundation::AsyncStatus) {
       winrt::impl::com_callback_args args{};
       args.data = handle.address();
 
       auto callback = [](winrt::impl::com_callback_args *args) noexcept -> int32_t {
-        std::experimental::coroutine_handle<>::from_address(args->data)();
+        std::coroutine_handle<>::from_address(args->data)();
         return S_OK;
       };