Rollout TurboModuleBinding::Prototype (#38220)

Summary: Pull Request resolved: #38220 We ran an experiment to test different implementations of TurboModules HostObjects, as the current one has various inefficiencies, such as re-creating HostFunctions on every property access. The strategy we found to be most efficient and flexible longer-term is to represent the TurboModule with a plain JavaScript object and use a HostObject as its prototype. Whenever a property is accessed through the prototype, we cache the property value on the plain object, so it can be efficiently resolved by the VM for future accesses. Changelog: [General] TurboModules are now exposed to JS as the prototype of a plain JS object, so methods can be cached Reviewed By: sammy-SC Differential Revision: D47258286 fbshipit-source-id: 4562ac5316164daaf673e713b35cb31315ff9652
facebook · Jul 10, 2023 · 20dba39 · 20dba39
1 parent c82f2e9
commit 20dba39
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diff --git a/.../react-native/ReactAndroid/src/main/java/com/facebook/react/config/ReactFeatureFlags.java b/.../react-native/ReactAndroid/src/main/java/com/facebook/react/config/ReactFeatureFlags.java
@@ -104,17 +104,6 @@ public class ReactFeatureFlags {
   /** Feature Flag to enable the pending event queue in fabric before mounting views */
   public static boolean enableFabricPendingEventQueue = false;
 
-  /**
-   * Feature flag that controls how turbo modules are exposed to JS
-   *
-   * <ul>
-   *   <li>0 = as a HostObject
-   *   <li>1 = as a plain object, backed with a HostObject as prototype
-   *   <li>2 = as a plain object, with all methods eagerly configured
-   * </ul>
-   */
-  public static int turboModuleBindingMode = 0;
-
   /**
    * Feature Flag to enable View Recycling. When enabled, individual ViewManagers must still opt-in.
    */

diff --git a/...act-native/ReactAndroid/src/main/jni/react/turbomodule/ReactCommon/TurboModuleManager.cpp b/...act-native/ReactAndroid/src/main/jni/react/turbomodule/ReactCommon/TurboModuleManager.cpp
@@ -91,17 +91,6 @@ class JMethodDescriptor : public jni::JavaClass<JMethodDescriptor> {
 };
 } // namespace
 
-constexpr static auto ReactFeatureFlagsJavaDescriptor =
-    "com/facebook/react/config/ReactFeatureFlags";
-
-static int getFeatureFlagValue(const char *name) {
-  static const auto reactFeatureFlagsJavaDescriptor =
-      jni::findClassStatic(ReactFeatureFlagsJavaDescriptor);
-  const auto field =
-      reactFeatureFlagsJavaDescriptor->getStaticField<jint>(name);
-  return reactFeatureFlagsJavaDescriptor->getStaticFieldValue(field);
-}
-
 TurboModuleManager::TurboModuleManager(
     jni::alias_ref<TurboModuleManager::javaobject> jThis,
     RuntimeExecutor runtimeExecutor,
@@ -319,20 +308,13 @@ void TurboModuleManager::installJSIBindings(bool shouldCreateLegacyModules) {
   bool isInteropLayerDisabled = !shouldCreateLegacyModules;
 
   runtimeExecutor_([this, isInteropLayerDisabled](jsi::Runtime &runtime) {
-    TurboModuleBindingMode bindingMode = static_cast<TurboModuleBindingMode>(
-        getFeatureFlagValue("turboModuleBindingMode"));
-
     if (isInteropLayerDisabled) {
-      TurboModuleBinding::install(
-          runtime, bindingMode, createTurboModuleProvider());
+      TurboModuleBinding::install(runtime, createTurboModuleProvider());
       return;
     }
 
     TurboModuleBinding::install(
-        runtime,
-        bindingMode,
-        createTurboModuleProvider(),
-        createLegacyModuleProvider());
+        runtime, createTurboModuleProvider(), createLegacyModuleProvider());
   });
 }
 

diff --git a/packages/react-native/ReactCommon/react/nativemodule/core/ReactCommon/TurboModuleBinding.cpp b/packages/react-native/ReactCommon/react/nativemodule/core/ReactCommon/TurboModuleBinding.cpp
@@ -95,13 +95,11 @@ static void defineReadOnlyGlobal(
  */
 
 TurboModuleBinding::TurboModuleBinding(
-    TurboModuleBindingMode bindingMode,
     TurboModuleProviderFunctionType &&moduleProvider)
-    : bindingMode_(bindingMode), moduleProvider_(std::move(moduleProvider)) {}
+    : moduleProvider_(std::move(moduleProvider)) {}
 
 void TurboModuleBinding::install(
     jsi::Runtime &runtime,
-    TurboModuleBindingMode bindingMode,
     TurboModuleProviderFunctionType &&moduleProvider,
     TurboModuleProviderFunctionType &&legacyModuleProvider) {
   runtime.global().setProperty(
@@ -111,8 +109,7 @@ void TurboModuleBinding::install(
           runtime,
           jsi::PropNameID::forAscii(runtime, "__turboModuleProxy"),
           1,
-          [binding =
-               TurboModuleBinding(bindingMode, std::move(moduleProvider))](
+          [binding = TurboModuleBinding(std::move(moduleProvider))](
               jsi::Runtime &rt,
               const jsi::Value &thisVal,
               const jsi::Value *args,
@@ -135,7 +132,7 @@ void TurboModuleBinding::install(
               runtime,
               std::make_shared<BridgelessNativeModuleProxy>(
                   std::make_unique<TurboModuleBinding>(
-                      bindingMode, std::move(legacyModuleProvider)))));
+                      std::move(legacyModuleProvider)))));
     } else {
       defineReadOnlyGlobal(
           runtime,
@@ -160,11 +157,6 @@ jsi::Value TurboModuleBinding::getModule(
     module = moduleProvider_(moduleName);
   }
   if (module) {
-    // Default behaviour
-    if (bindingMode_ == TurboModuleBindingMode::HostObject) {
-      return jsi::Object::createFromHostObject(runtime, std::move(module));
-    }
-
     // What is jsRepresentation? A cache for the TurboModule's properties
     // Henceforth, always return the cache (i.e: jsRepresentation) to JavaScript
     //
@@ -186,26 +178,19 @@ jsi::Value TurboModuleBinding::getModule(
     weakJsRepresentation =
         std::make_unique<jsi::WeakObject>(runtime, jsRepresentation);
 
-    if (bindingMode_ == TurboModuleBindingMode::Prototype) {
-      // Option 1: Lazily populate the jsRepresentation, on property access.
-      //
-      // How does this work?
-      //   1. Initially jsRepresentation is empty: {}
-      //   2. If property lookup on jsRepresentation fails, the JS runtime will
-      //   search jsRepresentation's prototype: jsi::Object(TurboModule).
-      //   3. TurboModule::get(runtime, propKey) executes. This creates the
-      //   property, caches it on jsRepresentation, then returns it to
-      //   JavaScript.
-      auto hostObject =
-          jsi::Object::createFromHostObject(runtime, std::move(module));
-      jsRepresentation.setProperty(runtime, "__proto__", std::move(hostObject));
-    } else {
-      // Option 2: Eagerly populate the jsRepresentation, on create.
-      // Object.assign(jsRepresentation, jsi::Object(TurboModule))
-      for (auto &propName : module->getPropertyNames(runtime)) {
-        module->get(runtime, propName);
-      }
-    }
+    // Lazily populate the jsRepresentation, on property access.
+    //
+    // How does this work?
+    //   1. Initially jsRepresentation is empty: {}
+    //   2. If property lookup on jsRepresentation fails, the JS runtime will
+    //   search jsRepresentation's prototype: jsi::Object(TurboModule).
+    //   3. TurboModule::get(runtime, propKey) executes. This creates the
+    //   property, caches it on jsRepresentation, then returns it to
+    //   JavaScript.
+    auto hostObject =
+        jsi::Object::createFromHostObject(runtime, std::move(module));
+    jsRepresentation.setProperty(runtime, "__proto__", std::move(hostObject));
+
     return jsRepresentation;
   } else {
     return jsi::Value::null();

diff --git a/packages/react-native/ReactCommon/react/nativemodule/core/ReactCommon/TurboModuleBinding.h b/packages/react-native/ReactCommon/react/nativemodule/core/ReactCommon/TurboModuleBinding.h
@@ -14,12 +14,6 @@
 
 namespace facebook::react {
 
-enum class TurboModuleBindingMode : uint8_t {
-  HostObject = 0,
-  Prototype = 1,
-  Eager = 2,
-};
-
 class BridgelessNativeModuleProxy;
 
 /**
@@ -33,13 +27,10 @@ class TurboModuleBinding {
    */
   static void install(
       jsi::Runtime &runtime,
-      TurboModuleBindingMode bindingMode,
       TurboModuleProviderFunctionType &&moduleProvider,
       TurboModuleProviderFunctionType &&legacyModuleProvider = nullptr);
 
-  TurboModuleBinding(
-      TurboModuleBindingMode bindingMode,
-      TurboModuleProviderFunctionType &&moduleProvider);
+  TurboModuleBinding(TurboModuleProviderFunctionType &&moduleProvider);
   virtual ~TurboModuleBinding();
 
  private:
@@ -52,7 +43,6 @@ class TurboModuleBinding {
   jsi::Value getModule(jsi::Runtime &runtime, const std::string &moduleName)
       const;
 
-  TurboModuleBindingMode bindingMode_;
   TurboModuleProviderFunctionType moduleProvider_;
 };
 

diff --git a/...tive/ReactCommon/react/nativemodule/core/platform/ios/ReactCommon/RCTTurboModuleManager.h b/...tive/ReactCommon/react/nativemodule/core/platform/ios/ReactCommon/RCTTurboModuleManager.h
@@ -17,8 +17,6 @@
 #import <ReactCommon/TurboModuleBinding.h>
 #import "RCTTurboModule.h"
 
-RCT_EXTERN void RCTTurboModuleSetBindingMode(facebook::react::TurboModuleBindingMode bindingMode);
-
 @protocol RCTTurboModuleManagerDelegate <NSObject>
 
 /**

diff --git a/...ive/ReactCommon/react/nativemodule/core/platform/ios/ReactCommon/RCTTurboModuleManager.mm b/...ive/ReactCommon/react/nativemodule/core/platform/ios/ReactCommon/RCTTurboModuleManager.mm
@@ -33,12 +33,6 @@
 using namespace facebook;
 using namespace facebook::react;
 
-static TurboModuleBindingMode sTurboModuleBindingMode = TurboModuleBindingMode::HostObject;
-void RCTTurboModuleSetBindingMode(TurboModuleBindingMode bindingMode)
-{
-  sTurboModuleBindingMode = bindingMode;
-}
-
 /**
  * A global variable whose address we use to associate method queues to id<RCTBridgeModule> objects.
  */
@@ -962,10 +956,9 @@ - (void)installJSBindings:(facebook::jsi::Runtime &)runtime
       return turboModule;
     };
 
-    TurboModuleBinding::install(
-        runtime, sTurboModuleBindingMode, std::move(turboModuleProvider), std::move(legacyModuleProvider));
+    TurboModuleBinding::install(runtime, std::move(turboModuleProvider), std::move(legacyModuleProvider));
   } else {
-    TurboModuleBinding::install(runtime, sTurboModuleBindingMode, std::move(turboModuleProvider));
+    TurboModuleBinding::install(runtime, std::move(turboModuleProvider));
   }
 }