From 499ac1f14b4347dcd7b918326a378a330e52bb3d Mon Sep 17 00:00:00 2001
From: Joshua Gross <joshuagross@fb.com>
Date: Fri, 18 Jun 2021 14:21:41 -0700
Subject: [PATCH] Resolve race condition in usage/teardown of
 EventEmitterWrapper

Summary:
In stopSurface we destroy these EventEmitters which is not a threadsafe operation. Wrap usage and destruction of these wrappers to prevent crashes.

This crash is caused by D29020768 (https://github.com/facebook/react-native/commit/25e8fbe8ffa1c91522e91819a781434093f8b759) which was landed to fix T92179998, which was in turn caused by D28938637 (https://github.com/facebook/react-native/commit/ac6d1982f4df55eca4da1cfc588dadc35bc005d0).

Changelog: [internal]

Reviewed By: sammy-SC, mdvacca

Differential Revision: D29239828

fbshipit-source-id: 6be5acf4a24b82c75c13fe9f1d16a87cce5b7e00
---
 .../fabric/events/EventEmitterWrapper.java    | 26 ++++++++++++-------
 1 file changed, 16 insertions(+), 10 deletions(-)

diff --git a/ReactAndroid/src/main/java/com/facebook/react/fabric/events/EventEmitterWrapper.java b/ReactAndroid/src/main/java/com/facebook/react/fabric/events/EventEmitterWrapper.java
index 69d0e1c8a8a..7938b793c5d 100644
--- a/ReactAndroid/src/main/java/com/facebook/react/fabric/events/EventEmitterWrapper.java
+++ b/ReactAndroid/src/main/java/com/facebook/react/fabric/events/EventEmitterWrapper.java
@@ -48,11 +48,13 @@ public class EventEmitterWrapper {
    * @param params {@link WritableMap} payload of the event
    */
   public void invoke(@NonNull String eventName, @Nullable WritableMap params) {
-    if (!isValid()) {
-      return;
+    synchronized (mHybridData) {
+      if (!isValid()) {
+        return;
+      }
+      NativeMap payload = params == null ? new WritableNativeMap() : (NativeMap) params;
+      invokeEvent(eventName, payload);
     }
-    NativeMap payload = params == null ? new WritableNativeMap() : (NativeMap) params;
-    invokeEvent(eventName, payload);
   }
 
   /**
@@ -64,16 +66,20 @@ public class EventEmitterWrapper {
    */
   public void invokeUnique(
       @NonNull String eventName, @Nullable WritableMap params, int customCoalesceKey) {
-    if (!isValid()) {
-      return;
+    synchronized (mHybridData) {
+      if (!isValid()) {
+        return;
+      }
+      NativeMap payload = params == null ? new WritableNativeMap() : (NativeMap) params;
+      invokeUniqueEvent(eventName, payload, customCoalesceKey);
     }
-    NativeMap payload = params == null ? new WritableNativeMap() : (NativeMap) params;
-    invokeUniqueEvent(eventName, payload, customCoalesceKey);
   }
 
   public void destroy() {
-    if (mHybridData != null) {
-      mHybridData.resetNative();
+    synchronized (mHybridData) {
+      if (mHybridData != null) {
+        mHybridData.resetNative();
+      }
     }
   }