From 35c9585f5fa30ab18da8b55492e1f97cc44c4d44 Mon Sep 17 00:00:00 2001
From: christosts <christosts@google.com>
Date: Wed, 8 Jun 2022 16:23:18 +0000
Subject: [PATCH] Avoid using ConcurrentHashMap

Use Collections.synchronizedSet() instead of creating a set from a
ConcurrentHashMap because ConcurrentHashMap has a bug in APIs 21/22
that can result in lost updates.

PiperOrigin-RevId: 453696565
(cherry picked from commit d506c709c9a793d751908aac879f2f85b74f7b58)
---
 .../java/androidx/media3/session/MediaSessionService.java    | 5 +++--
 .../main/java/androidx/media3/session/MediaSessionStub.java  | 5 +++--
 2 files changed, 6 insertions(+), 4 deletions(-)

diff --git a/libraries/session/src/main/java/androidx/media3/session/MediaSessionService.java b/libraries/session/src/main/java/androidx/media3/session/MediaSessionService.java
index 0cb00a915f..d44c3d0da1 100644
--- a/libraries/session/src/main/java/androidx/media3/session/MediaSessionService.java
+++ b/libraries/session/src/main/java/androidx/media3/session/MediaSessionService.java
@@ -43,10 +43,10 @@ import androidx.media3.session.MediaSession.ControllerInfo;
 import java.lang.ref.WeakReference;
 import java.util.ArrayList;
 import java.util.Collections;
+import java.util.HashSet;
 import java.util.List;
 import java.util.Map;
 import java.util.Set;
-import java.util.concurrent.ConcurrentHashMap;
 import org.checkerframework.checker.nullness.qual.MonotonicNonNull;
 
 /**
@@ -472,7 +472,8 @@ public abstract class MediaSessionService extends Service {
       Context context = serviceReference.getApplicationContext();
       handler = new Handler(context.getMainLooper());
       mediaSessionManager = MediaSessionManager.getSessionManager(context);
-      pendingControllers = Collections.newSetFromMap(new ConcurrentHashMap<>());
+      // ConcurrentHashMap has a bug in APIs 21-22 that can result in lost updates.
+      pendingControllers = Collections.synchronizedSet(new HashSet<>());
     }
 
     @Override
diff --git a/libraries/session/src/main/java/androidx/media3/session/MediaSessionStub.java b/libraries/session/src/main/java/androidx/media3/session/MediaSessionStub.java
index 672edf3a30..2a8bbb8b59 100644
--- a/libraries/session/src/main/java/androidx/media3/session/MediaSessionStub.java
+++ b/libraries/session/src/main/java/androidx/media3/session/MediaSessionStub.java
@@ -83,10 +83,10 @@ import com.google.common.util.concurrent.MoreExecutors;
 import java.lang.ref.WeakReference;
 import java.util.Collections;
 import java.util.Deque;
+import java.util.HashSet;
 import java.util.List;
 import java.util.Set;
 import java.util.concurrent.CancellationException;
-import java.util.concurrent.ConcurrentHashMap;
 import java.util.concurrent.ExecutionException;
 
 /**
@@ -109,7 +109,8 @@ import java.util.concurrent.ExecutionException;
     this.sessionImpl = new WeakReference<>(sessionImpl);
     sessionManager = MediaSessionManager.getSessionManager(sessionImpl.getContext());
     connectedControllersManager = new ConnectedControllersManager<>(sessionImpl);
-    pendingControllers = Collections.newSetFromMap(new ConcurrentHashMap<>());
+    // ConcurrentHashMap has a bug in APIs 21-22 that can result in lost updates.
+    pendingControllers = Collections.synchronizedSet(new HashSet<>());
   }
 
   public ConnectedControllersManager<IBinder> getConnectedControllersManager() {