Reenable optimization in TMs to avoid going through a dynamic for callbacks/promises (#14691)

acoates-ms · web-flow · commit 721dff3b65b0 · 2025-05-19T14:10:39.000-07:00
* Reenable optimization in TMs to avoid going through a dynamic for callbacks/promises

* Change files
diff --git a/change/react-native-windows-9adb4921-0e07-4622-8839-b36a3e017a3a.json b/change/react-native-windows-9adb4921-0e07-4622-8839-b36a3e017a3a.json
@@ -0,0 +1,7 @@
+{
+  "type": "prerelease",
+  "comment": "Reenable optimization in TMs to avoid going through a dynamic for callbacks/promises",
+  "packageName": "react-native-windows",
+  "email": "30809111+acoates-ms@users.noreply.github.com",
+  "dependentChangeType": "patch"
+}
diff --git a/vnext/Microsoft.ReactNative/CallInvokerWriter.cpp b/vnext/Microsoft.ReactNative/CallInvokerWriter.cpp
@@ -15,7 +15,9 @@ namespace winrt::Microsoft::ReactNative {
 CallInvokerWriter::CallInvokerWriter(
     const std::shared_ptr<facebook::react::CallInvoker> &jsInvoker,
     std::weak_ptr<LongLivedJsiRuntime> jsiRuntimeHolder) noexcept
-    : m_callInvoker(jsInvoker), m_jsiRuntimeHolder(std::move(jsiRuntimeHolder)) {}
+    : m_callInvoker(jsInvoker),
+      m_jsiRuntimeHolder(std::move(jsiRuntimeHolder)),
+      m_threadId(std::this_thread::get_id()) {}
 
 CallInvokerWriter::~CallInvokerWriter() {
   if (auto jsiRuntimeHolder = m_jsiRuntimeHolder.lock()) {
@@ -26,32 +28,30 @@ CallInvokerWriter::~CallInvokerWriter() {
 void CallInvokerWriter::WithResultArgs(
     Mso::Functor<void(facebook::jsi::Runtime &rt, facebook::jsi::Value const *args, size_t argCount)>
         handler) noexcept {
-  /*
-    if (m_jsDispatcher.HasThreadAccess()) {
-      VerifyElseCrash(!m_dynamicWriter);
-      if (auto jsiRuntimeHolder = m_jsiRuntimeHolder.lock()) {
-        const facebook::jsi::Value *args{nullptr};
-        size_t argCount{0};
-        m_jsiWriter->AccessResultAsArgs(args, argCount);
-        handler(jsiRuntimeHolder->Runtime(), args, argCount);
-        m_jsiWriter = nullptr;
-      }
-    } else {
-  */
-  VerifyElseCrash(!m_jsiWriter);
-  folly::dynamic dynValue = m_dynamicWriter->TakeValue();
-  VerifyElseCrash(dynValue.isArray());
-  m_callInvoker->invokeAsync(
-      [handler, dynValue = std::move(dynValue), weakJsiRuntimeHolder = m_jsiRuntimeHolder, self = get_strong()](
-          facebook::jsi::Runtime &runtime) {
-        std::vector<facebook::jsi::Value> args;
-        args.reserve(dynValue.size());
-        for (auto const &item : dynValue) {
-          args.emplace_back(facebook::jsi::valueFromDynamic(runtime, item));
-        }
-        handler(runtime, args.data(), args.size());
-      });
-  //}
+  if (m_threadId == std::this_thread::get_id() && m_fastPath) {
+    VerifyElseCrash(!m_dynamicWriter);
+    if (auto jsiRuntimeHolder = m_jsiRuntimeHolder.lock()) {
+      const facebook::jsi::Value *args{nullptr};
+      size_t argCount{0};
+      m_jsiWriter->AccessResultAsArgs(args, argCount);
+      handler(jsiRuntimeHolder->Runtime(), args, argCount);
+      m_jsiWriter = nullptr;
+    }
+  } else {
+    VerifyElseCrash(!m_jsiWriter);
+    folly::dynamic dynValue = m_dynamicWriter->TakeValue();
+    VerifyElseCrash(dynValue.isArray());
+    m_callInvoker->invokeAsync(
+        [handler, dynValue = std::move(dynValue), weakJsiRuntimeHolder = m_jsiRuntimeHolder, self = get_strong()](
+            facebook::jsi::Runtime &runtime) {
+          std::vector<facebook::jsi::Value> args;
+          args.reserve(dynValue.size());
+          for (auto const &item : dynValue) {
+            args.emplace_back(facebook::jsi::valueFromDynamic(runtime, item));
+          }
+          handler(runtime, args.data(), args.size());
+        });
+  }
 }
 
 void CallInvokerWriter::WriteNull() noexcept {
@@ -96,24 +96,26 @@ void CallInvokerWriter::WriteArrayEnd() noexcept {
 
 IJSValueWriter CallInvokerWriter::GetWriter() noexcept {
   if (!m_writer) {
-    /*
-        if (m_jsDispatcher.HasThreadAccess()) {
-          if (auto jsiRuntimeHolder = m_jsiRuntimeHolder.lock()) {
-            m_jsiWriter = winrt::make_self<JsiWriter>(jsiRuntimeHolder->Runtime());
-            m_writer = m_jsiWriter.as<IJSValueWriter>();
-          } else {
-            m_writer = winrt::make<JSNoopWriter>();
-          }
-        } else {
-         */
-    m_dynamicWriter = winrt::make_self<DynamicWriter>();
-    m_writer = m_dynamicWriter.as<IJSValueWriter>();
-    //}
+    if (m_threadId == std::this_thread::get_id() && m_fastPath) {
+      if (auto jsiRuntimeHolder = m_jsiRuntimeHolder.lock()) {
+        m_jsiWriter = winrt::make_self<JsiWriter>(jsiRuntimeHolder->Runtime());
+        m_writer = m_jsiWriter.as<IJSValueWriter>();
+      } else {
+        m_writer = winrt::make<JSNoopWriter>();
+      }
+    } else {
+      m_dynamicWriter = winrt::make_self<DynamicWriter>();
+      m_writer = m_dynamicWriter.as<IJSValueWriter>();
+    }
   }
-  Debug(VerifyElseCrash(m_dynamicWriter != nullptr /* || m_jsDispatcher.HasThreadAccess()*/));
+  Debug(VerifyElseCrash(m_dynamicWriter != nullptr || (m_threadId == std::this_thread::get_id() && m_fastPath)));
   return m_writer;
 }
 
+void CallInvokerWriter::ExitCurrentCallInvokeScope() noexcept {
+  m_fastPath = false;
+}
+
 //===========================================================================
 // JSNoopWriter implementation
 //===========================================================================
@@ -129,4 +131,4 @@ void JSNoopWriter::WriteObjectEnd() noexcept {}
 void JSNoopWriter::WriteArrayBegin() noexcept {}
 void JSNoopWriter::WriteArrayEnd() noexcept {}
 
-} // namespace winrt::Microsoft::ReactNative
+} // namespace winrt::Microsoft::ReactNative
diff --git a/vnext/Microsoft.ReactNative/CallInvokerWriter.h b/vnext/Microsoft.ReactNative/CallInvokerWriter.h
@@ -34,6 +34,10 @@ struct CallInvokerWriter : winrt::implements<CallInvokerWriter, IJSValueWriter>
   void WriteArrayBegin() noexcept;
   void WriteArrayEnd() noexcept;
 
+  // This should be called before the code flow exits the scope of the CallInvoker,
+  // thus requiring the CallInokerWriter to call m_callInvoker->invokeAsync to call back into JS.
+  void ExitCurrentCallInvokeScope() noexcept;
+
  private:
   IJSValueWriter GetWriter() noexcept;
 
@@ -43,6 +47,12 @@ struct CallInvokerWriter : winrt::implements<CallInvokerWriter, IJSValueWriter>
   winrt::com_ptr<DynamicWriter> m_dynamicWriter;
   winrt::com_ptr<JsiWriter> m_jsiWriter;
   IJSValueWriter m_writer;
+
+  // If a callback is invoked synchronously we can call the JS callback directly.
+  // However, if we post to another thread, or call the callback on the same thread but after we exit the current
+  // RuntimeExecutor callback, then we need to save the callback args in a dynamic and post it back to the CallInvoker
+  bool m_fastPath{true};
+  const std::thread::id m_threadId;
 };
 
 // Special IJSValueWriter that does nothing.
@@ -61,4 +71,4 @@ struct JSNoopWriter : winrt::implements<JSNoopWriter, IJSValueWriter> {
   void WriteArrayEnd() noexcept;
 };
 
-} // namespace winrt::Microsoft::ReactNative
+} // namespace winrt::Microsoft::ReactNative
diff --git a/vnext/Microsoft.ReactNative/TurboModulesProvider.cpp b/vnext/Microsoft.ReactNative/TurboModulesProvider.cpp
@@ -225,11 +225,13 @@ class TurboModuleImpl : public facebook::react::TurboModule {
                   VerifyElseCrash(argCount > 0);
                   if (auto strongLongLivedObjectCollection = longLivedObjectCollection.lock()) {
                     auto jsiRuntimeHolder = LongLivedJsiRuntime::CreateWeak(strongLongLivedObjectCollection, rt);
+                    auto writer = winrt::make<CallInvokerWriter>(jsInvoker, jsiRuntimeHolder);
                     method(
                         winrt::make<JsiReader>(rt, args, argCount - 1),
-                        winrt::make<CallInvokerWriter>(jsInvoker, jsiRuntimeHolder),
+                        writer,
                         MakeCallback(rt, strongLongLivedObjectCollection, args[argCount - 1]),
                         nullptr);
+                    winrt::get_self<CallInvokerWriter>(writer)->ExitCurrentCallInvokeScope();
                   }
                   return facebook::jsi::Value::undefined();
                 });
@@ -253,9 +255,10 @@ class TurboModuleImpl : public facebook::react::TurboModule {
                     auto weakCallback2 = LongLivedJsiFunction::CreateWeak(
                         strongLongLivedObjectCollection, rt, args[argCount - 1].getObject(rt).getFunction(rt));
 
+                    auto writer = winrt::make<CallInvokerWriter>(jsInvoker, jsiRuntimeHolder);
                     method(
                         winrt::make<JsiReader>(rt, args, argCount - 2),
-                        winrt::make<CallInvokerWriter>(jsInvoker, jsiRuntimeHolder),
+                        writer,
                         [weakCallback1, weakCallback2, jsiRuntimeHolder](const IJSValueWriter &writer) noexcept {
                           writer.as<CallInvokerWriter>()->WithResultArgs(
                               [weakCallback1, weakCallback2, jsiRuntimeHolder](
@@ -288,6 +291,7 @@ class TurboModuleImpl : public facebook::react::TurboModule {
                                 }
                               });
                         });
+                    winrt::get_self<CallInvokerWriter>(writer)->ExitCurrentCallInvokeScope();
                   }
                   return facebook::jsi::Value::undefined();
                 });
@@ -369,6 +373,7 @@ class TurboModuleImpl : public facebook::react::TurboModule {
                                       }
                                     });
                               });
+                          winrt::get_self<CallInvokerWriter>(argWriter)->ExitCurrentCallInvokeScope();
                         });
                   }
                   return facebook::jsi::Value::undefined();
