Remove background_executor flag

Summary: changelog: [internal] Background executor has been shipped on both platforms for a long time. I've kept the flag around because I wanted to run tests and compare Concurrent Mode vs Background Executor. The intention was to see if we can get rid of Background Executor to simplify the threading model. Since then, React team has moved away from Concurrent Mode towards more gradual rollout of concurrent rendering and it no longer makes sense to do this comparison. Right now, we don't have a concern with concurrent rendering and Background Executor. If we ever want to run the an experiment, this gating will need to be added again. Reviewed By: javache Differential Revision: D32674798 fbshipit-source-id: a1e51c9c5b8e48efa4cb0f25379d58e7eb80ccd9
facebook · Dec 2, 2021 · 387e79f · 387e79f
1 parent ae67c5a
commit 387e79f
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Showing 3 changed files with 44 additions and 70 deletions.
diff --git a/React/Fabric/RCTSurfacePresenter.mm b/React/Fabric/RCTSurfacePresenter.mm
@@ -285,9 +285,7 @@ - (RCTScheduler *)_createScheduler
     return std::make_unique<MainRunLoopObserver>(activities, owner);
   };
 
-  if (reactNativeConfig && reactNativeConfig->getBool("react_fabric:enable_background_executor_ios")) {
-    toolbox.backgroundExecutor = RCTGetBackgroundExecutor();
-  }
+  toolbox.backgroundExecutor = RCTGetBackgroundExecutor();
 
   toolbox.synchronousEventBeatFactory =
       [runtimeExecutor, runtimeScheduler = runtimeScheduler](EventBeat::SharedOwnerBox const &ownerBox) {

diff --git a/ReactAndroid/src/main/java/com/facebook/react/fabric/jni/Binding.cpp b/ReactAndroid/src/main/java/com/facebook/react/fabric/jni/Binding.cpp
@@ -606,11 +606,8 @@ void Binding::installFabricUIManager(
   toolbox.synchronousEventBeatFactory = synchronousBeatFactory;
   toolbox.asynchronousEventBeatFactory = asynchronousBeatFactory;
 
-  if (reactNativeConfig_->getBool(
-          "react_fabric:enable_background_executor_android")) {
-    backgroundExecutor_ = std::make_unique<JBackgroundExecutor>();
-    toolbox.backgroundExecutor = backgroundExecutor_->get();
-  }
+  backgroundExecutor_ = std::make_unique<JBackgroundExecutor>();
+  toolbox.backgroundExecutor = backgroundExecutor_->get();
 
   animationDriver_ = std::make_shared<LayoutAnimationDriver>(
       runtimeExecutor, contextContainer, this);

diff --git a/ReactCommon/react/renderer/uimanager/UIManagerBinding.cpp b/ReactCommon/react/renderer/uimanager/UIManagerBinding.cpp
@@ -531,69 +531,48 @@ jsi::Value UIManagerBinding::get(
   }
 
   if (methodName == "completeRoot") {
-    if (uiManager->backgroundExecutor_) {
-      std::weak_ptr<UIManager> weakUIManager = uiManager_;
-      // Enhanced version of the method that uses `backgroundExecutor` and
-      // captures a shared pointer to `UIManager`.
-      return jsi::Function::createFromHostFunction(
-          runtime,
-          name,
-          2,
-          [weakUIManager, uiManager](
-              jsi::Runtime &runtime,
-              jsi::Value const &thisValue,
-              jsi::Value const *arguments,
-              size_t count) noexcept -> jsi::Value {
-            auto surfaceId = surfaceIdFromValue(runtime, arguments[0]);
-            auto weakShadowNodeList =
-                weakShadowNodeListFromValue(runtime, arguments[1]);
-            static std::atomic_uint_fast8_t completeRootEventCounter{0};
-            static std::atomic_uint_fast32_t mostRecentSurfaceId{0};
-            completeRootEventCounter += 1;
-            mostRecentSurfaceId = surfaceId;
-            uiManager->backgroundExecutor_(
-                [weakUIManager,
-                 weakShadowNodeList,
-                 surfaceId,
-                 eventCount = completeRootEventCounter.load()] {
-                  auto shouldYield = [=]() -> bool {
-                    // If `completeRootEventCounter` was incremented, another
-                    // `completeSurface` call has been scheduled and current
-                    // `completeSurface` should yield to it.
-                    return completeRootEventCounter > eventCount &&
-                        mostRecentSurfaceId == surfaceId;
-                  };
-                  auto shadowNodeList =
-                      shadowNodeListFromWeakList(weakShadowNodeList);
-                  auto strongUIManager = weakUIManager.lock();
-                  if (shadowNodeList && strongUIManager) {
-                    strongUIManager->completeSurface(
-                        surfaceId, shadowNodeList, {true, shouldYield});
-                  }
-                });
-
-            return jsi::Value::undefined();
-          });
-    } else {
-      // Basic version of the method that does *not* use `backgroundExecutor`
-      // and does *not* capture a shared pointer to `UIManager`.
-      return jsi::Function::createFromHostFunction(
-          runtime,
-          name,
-          2,
-          [uiManager](
-              jsi::Runtime &runtime,
-              jsi::Value const &thisValue,
-              jsi::Value const *arguments,
-              size_t count) noexcept -> jsi::Value {
-            uiManager->completeSurface(
-                surfaceIdFromValue(runtime, arguments[0]),
-                shadowNodeListFromValue(runtime, arguments[1]),
-                {true, {}});
+    std::weak_ptr<UIManager> weakUIManager = uiManager_;
+    // Enhanced version of the method that uses `backgroundExecutor` and
+    // captures a shared pointer to `UIManager`.
+    return jsi::Function::createFromHostFunction(
+        runtime,
+        name,
+        2,
+        [weakUIManager, uiManager](
+            jsi::Runtime &runtime,
+            jsi::Value const &thisValue,
+            jsi::Value const *arguments,
+            size_t count) noexcept -> jsi::Value {
+          auto surfaceId = surfaceIdFromValue(runtime, arguments[0]);
+          auto weakShadowNodeList =
+              weakShadowNodeListFromValue(runtime, arguments[1]);
+          static std::atomic_uint_fast8_t completeRootEventCounter{0};
+          static std::atomic_uint_fast32_t mostRecentSurfaceId{0};
+          completeRootEventCounter += 1;
+          mostRecentSurfaceId = surfaceId;
+          uiManager->backgroundExecutor_(
+              [weakUIManager,
+               weakShadowNodeList,
+               surfaceId,
+               eventCount = completeRootEventCounter.load()] {
+                auto shouldYield = [=]() -> bool {
+                  // If `completeRootEventCounter` was incremented, another
+                  // `completeSurface` call has been scheduled and current
+                  // `completeSurface` should yield to it.
+                  return completeRootEventCounter > eventCount &&
+                      mostRecentSurfaceId == surfaceId;
+                };
+                auto shadowNodeList =
+                    shadowNodeListFromWeakList(weakShadowNodeList);
+                auto strongUIManager = weakUIManager.lock();
+                if (shadowNodeList && strongUIManager) {
+                  strongUIManager->completeSurface(
+                      surfaceId, shadowNodeList, {true, shouldYield});
+                }
+              });
 
-            return jsi::Value::undefined();
-          });
-    }
+          return jsi::Value::undefined();
+        });
   }
 
   if (methodName == "registerEventHandler") {