From cfd425406a08d49e506238f74c2ba40bfdc8e9e4 Mon Sep 17 00:00:00 2001
From: Samuel Susla <samuelsusla@fb.com>
Date: Mon, 26 Jul 2021 10:19:22 -0700
Subject: [PATCH] Back out "Use atomic pointer to prevent race during teardown"

Summary:
Changelog: [internal]

Original commit changeset: 390e773283a7

Original diff didn't resolve crash T82119127. Let's back this out and investigate again.

Reviewed By: mdvacca

Differential Revision: D29909878

fbshipit-source-id: 54b054f4a5c97b8f6369f8790c2cf32a56c4fbd2
---
 .../react/renderer/uimanager/UIManager.cpp    | 30 ++++++++-----------
 .../react/renderer/uimanager/UIManager.h      |  2 +-
 2 files changed, 13 insertions(+), 19 deletions(-)

diff --git a/ReactCommon/react/renderer/uimanager/UIManager.cpp b/ReactCommon/react/renderer/uimanager/UIManager.cpp
index fd6114161c4..a15c46313ab 100644
--- a/ReactCommon/react/renderer/uimanager/UIManager.cpp
+++ b/ReactCommon/react/renderer/uimanager/UIManager.cpp
@@ -72,9 +72,8 @@ SharedShadowNode UIManager::createNode(
       },
       family);
 
-  auto delegate = delegate_.load();
-  if (delegate) {
-    delegate->uiManagerDidCreateShadowNode(*shadowNode.get());
+  if (delegate_) {
+    delegate_->uiManagerDidCreateShadowNode(*shadowNode.get());
   }
   if (leakChecker_) {
     leakChecker_->uiManagerDidCreateShadowNodeFamily(family);
@@ -100,9 +99,8 @@ SharedShadowNode UIManager::cloneNode(
           /* .children = */ children,
       });
 
-  auto delegate = delegate_.load();
-  if (delegate) {
-    delegate->uiManagerDidCloneShadowNode(
+  if (delegate_) {
+    delegate_->uiManagerDidCloneShadowNode(
         *shadowNode.get(), *clonedShadowNode.get());
   }
 
@@ -142,9 +140,8 @@ void UIManager::setIsJSResponder(
     ShadowNode::Shared const &shadowNode,
     bool isJSResponder,
     bool blockNativeResponder) const {
-  auto delegate = delegate_.load();
-  if (delegate) {
-    delegate->uiManagerDidSetIsJSResponder(
+  if (delegate_) {
+    delegate_->uiManagerDidSetIsJSResponder(
         shadowNode, isJSResponder, blockNativeResponder);
   }
 }
@@ -326,18 +323,16 @@ void UIManager::dispatchCommand(
     const ShadowNode::Shared &shadowNode,
     std::string const &commandName,
     folly::dynamic const args) const {
-  auto delegate = delegate_.load();
-  if (delegate) {
-    delegate->uiManagerDidDispatchCommand(shadowNode, commandName, args);
+  if (delegate_) {
+    delegate_->uiManagerDidDispatchCommand(shadowNode, commandName, args);
   }
 }
 
 void UIManager::sendAccessibilityEvent(
     const ShadowNode::Shared &shadowNode,
     std::string const &eventType) {
-  auto delegate = delegate_.load();
-  if (delegate) {
-    delegate->uiManagerDidSendAccessibilityEvent(shadowNode, eventType);
+  if (delegate_) {
+    delegate_->uiManagerDidSendAccessibilityEvent(shadowNode, eventType);
   }
 }
 
@@ -424,9 +419,8 @@ void UIManager::shadowTreeDidFinishTransaction(
     MountingCoordinator::Shared const &mountingCoordinator) const {
   SystraceSection s("UIManager::shadowTreeDidFinishTransaction");
 
-  auto delegate = delegate_.load();
-  if (delegate) {
-    delegate->uiManagerDidFinishTransaction(mountingCoordinator);
+  if (delegate_) {
+    delegate_->uiManagerDidFinishTransaction(mountingCoordinator);
   }
 }
 
diff --git a/ReactCommon/react/renderer/uimanager/UIManager.h b/ReactCommon/react/renderer/uimanager/UIManager.h
index 285df897d1e..13729bae024 100644
--- a/ReactCommon/react/renderer/uimanager/UIManager.h
+++ b/ReactCommon/react/renderer/uimanager/UIManager.h
@@ -184,7 +184,7 @@ class UIManager final : public ShadowTreeDelegate {
   ShadowTreeRegistry const &getShadowTreeRegistry() const;
 
   SharedComponentDescriptorRegistry componentDescriptorRegistry_;
-  std::atomic<UIManagerDelegate *> delegate_;
+  UIManagerDelegate *delegate_;
   std::atomic<UIManagerAnimationDelegate *> animationDelegate_{nullptr};
   RuntimeExecutor const runtimeExecutor_{};
   ShadowTreeRegistry shadowTreeRegistry_{};