From c9826ba4a93f4ac4b3026c27ed0ca3668d4d0328 Mon Sep 17 00:00:00 2001
From: Aaron Chiu <aaronechiu@fb.com>
Date: Fri, 14 Apr 2017 02:03:56 -0700
Subject: [PATCH] make mHasDispatchScheduledCount in EventDispatcher atomic

Reviewed By: achen1

Differential Revision: D4882881

fbshipit-source-id: ac9a985287bd4720846ecde97ebb4935963c0d9f
---
 .../react/uimanager/events/EventDispatcher.java      | 12 ++++++------
 1 file changed, 6 insertions(+), 6 deletions(-)

diff --git a/ReactAndroid/src/main/java/com/facebook/react/uimanager/events/EventDispatcher.java b/ReactAndroid/src/main/java/com/facebook/react/uimanager/events/EventDispatcher.java
index 540714b2f..22e6c35f5 100644
--- a/ReactAndroid/src/main/java/com/facebook/react/uimanager/events/EventDispatcher.java
+++ b/ReactAndroid/src/main/java/com/facebook/react/uimanager/events/EventDispatcher.java
@@ -15,6 +15,7 @@ import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.Comparator;
 import java.util.Map;
+import java.util.concurrent.atomic.AtomicInteger;
 
 import android.util.LongSparseArray;
 
@@ -93,19 +94,19 @@ public class EventDispatcher implements LifecycleEventListener {
   private final DispatchEventsRunnable mDispatchEventsRunnable = new DispatchEventsRunnable();
   private final ArrayList<Event> mEventStaging = new ArrayList<>();
   private final ArrayList<EventDispatcherListener> mListeners = new ArrayList<>();
+  private final ScheduleDispatchFrameCallback mCurrentFrameCallback =
+    new ScheduleDispatchFrameCallback();
+  private final AtomicInteger mHasDispatchScheduledCount = new AtomicInteger();
 
   private Event[] mEventsToDispatch = new Event[16];
   private int mEventsToDispatchSize = 0;
   private volatile @Nullable RCTEventEmitter mRCTEventEmitter;
-  private final ScheduleDispatchFrameCallback mCurrentFrameCallback;
   private short mNextEventTypeId = 0;
   private volatile boolean mHasDispatchScheduled = false;
-  private volatile int mHasDispatchScheduledCount = 0;
 
   public EventDispatcher(ReactApplicationContext reactContext) {
     mReactContext = reactContext;
     mReactContext.addLifecycleEventListener(this);
-    mCurrentFrameCallback = new ScheduleDispatchFrameCallback();
   }
 
   /**
@@ -279,7 +280,7 @@ public class EventDispatcher implements LifecycleEventListener {
           Systrace.startAsyncFlow(
               Systrace.TRACE_TAG_REACT_JAVA_BRIDGE,
               "ScheduleDispatchFrameCallback",
-              mHasDispatchScheduledCount);
+              mHasDispatchScheduledCount.get());
           mReactContext.runOnJSQueueThread(mDispatchEventsRunnable);
         }
       } finally {
@@ -331,9 +332,8 @@ public class EventDispatcher implements LifecycleEventListener {
         Systrace.endAsyncFlow(
             Systrace.TRACE_TAG_REACT_JAVA_BRIDGE,
             "ScheduleDispatchFrameCallback",
-            mHasDispatchScheduledCount);
+            mHasDispatchScheduledCount.getAndIncrement());
         mHasDispatchScheduled = false;
-        mHasDispatchScheduledCount++;
         Assertions.assertNotNull(mRCTEventEmitter);
         synchronized (mEventsToDispatchLock) {
           // We avoid allocating an array and iterator, and "sorting" if we don't need to.