From 2e44b138f39de68b3b895c01678cd3d8fbe22f80 Mon Sep 17 00:00:00 2001
From: David Drysdale <drysdale@google.com>
Date: Wed, 2 Dec 2020 13:17:57 -0800
Subject: [PATCH] Make CallbackManager.hasEverSetCallback atomic

PiperOrigin-RevId: 345298471
---
 java/arcs/core/storage/util/CallbackManager.kt | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/java/arcs/core/storage/util/CallbackManager.kt b/java/arcs/core/storage/util/CallbackManager.kt
index 307cc7934ce..c2b2031a050 100644
--- a/java/arcs/core/storage/util/CallbackManager.kt
+++ b/java/arcs/core/storage/util/CallbackManager.kt
@@ -35,7 +35,7 @@ class CallbackManager<T>(
   // token for the current map and the addition of that callback and token to the map.
   private var callbacksMap = atomic(emptyMap<Int, Callback<T>>())
 
-  private var hasEverSetCallback = false
+  private var hasEverSetCallback = atomic(false)
 
   val callbacks: Collection<Callback<T>>
     get() = callbacksMap.value.values
@@ -56,7 +56,7 @@ class CallbackManager<T>(
       token = tokenGenerator(it.keys)
       it + (token to callback)
     }
-    hasEverSetCallback = true
+    hasEverSetCallback.value = true
     return token
   }
 
@@ -86,7 +86,7 @@ class CallbackManager<T>(
 
   /** True if no callbacks are registered, and at least one has been registered before. */
   fun hasBecomeEmpty(): Boolean {
-    return hasEverSetCallback && callbacksMap.value.isEmpty()
+    return hasEverSetCallback.value && callbacksMap.value.isEmpty()
   }
 
   /** Remove all currently registered callbacks. */