IAppOpsCallback has weak reference to PlayerBase

The implementation of the IAppOpsCallback interface was an inner class
  that implicitly held a strong reference to the PlayerBase
  instance, preventing subclasses of PlayerBase to be GC'd.
The fix consists in making the IAppOpsCallback implementation be a static
  class and hold a weak reference to PlayerBase.

Test: see bug
Bug: 35359144

Change-Id: Ic97d07dad0be2376eef160d01ff4e4a9e5ee0bcd

1 files changed, 33 insertions, 17 deletions

diff --git a/media/java/android/media/PlayerBase.java b/media/java/android/media/PlayerBase.java
index 72be9f71d3a8..9bd93aa31abf 100644
--- a/media/java/android/media/PlayerBase.java
+++ b/media/java/android/media/PlayerBase.java
@@ -46,11 +46,11 @@ import java.util.Objects;
  */
 public abstract class PlayerBase {
 
-    private final static String TAG = "PlayerBase";
-    private final static boolean DEBUG = false;
+    private static final String TAG = "PlayerBase";
+    private static final boolean DEBUG = false;
     private static IAudioService sService; //lazy initialization, use getService()
     /** Debug app ops */
-    protected static final boolean DEBUG_APP_OPS = Log.isLoggable(TAG + ".AO", Log.DEBUG);
+    private static final boolean DEBUG_APP_OPS = false;
 
     // parameters of the player that affect AppOps
     protected AudioAttributes mAttributes;
@@ -95,19 +95,9 @@ public abstract class PlayerBase {
         IBinder b = ServiceManager.getService(Context.APP_OPS_SERVICE);
         mAppOps = IAppOpsService.Stub.asInterface(b);
         // initialize mHasAppOpsPlayAudio
-        synchronized (mLock) {
-            updateAppOpsPlayAudio_sync();
-        }
+        updateAppOpsPlayAudio();
         // register a callback to monitor whether the OP_PLAY_AUDIO is still allowed
-        mAppOpsCallback = new IAppOpsCallback.Stub() {
-            public void opChanged(int op, int uid, String packageName) {
-                synchronized (mLock) {
-                    if (op == AppOpsManager.OP_PLAY_AUDIO) {
-                        updateAppOpsPlayAudio_sync();
-                    }
-                }
-            }
-        };
+        mAppOpsCallback = new IAppOpsCallbackWrapper(this);
         try {
             mAppOps.startWatchingMode(AppOpsManager.OP_PLAY_AUDIO,
                     ActivityThread.currentPackageName(), mAppOpsCallback);
@@ -258,6 +248,12 @@ public abstract class PlayerBase {
         }
     }
 
+    private void updateAppOpsPlayAudio() {
+        synchronized (mLock) {
+            updateAppOpsPlayAudio_sync();
+        }
+    }
+
     /**
      * To be called whenever a condition that might affect audibility of this player is updated.
      * Must be called synchronized on mLock.
@@ -405,6 +401,26 @@ public abstract class PlayerBase {
     abstract void playerStop();
 
     //=====================================================================
+    private static class IAppOpsCallbackWrapper extends IAppOpsCallback.Stub {
+        private final WeakReference<PlayerBase> mWeakPB;
+
+        public IAppOpsCallbackWrapper(PlayerBase pb) {
+            mWeakPB = new WeakReference<PlayerBase>(pb);
+        }
+
+        @Override
+        public void opChanged(int op, int uid, String packageName) {
+            if (op == AppOpsManager.OP_PLAY_AUDIO) {
+                if (DEBUG_APP_OPS) { Log.v(TAG, "opChanged: op=PLAY_AUDIO pack=" + packageName); }
+                final PlayerBase pb = mWeakPB.get();
+                if (pb != null) {
+                    pb.updateAppOpsPlayAudio();
+                }
+            }
+        }
+    }
+
+    //=====================================================================
     /**
      * Wrapper around an implementation of IPlayer for all subclasses of PlayerBase
      * that doesn't keep a strong reference on PlayerBase
@@ -482,8 +498,8 @@ public abstract class PlayerBase {
     public static class PlayerIdCard implements Parcelable {
         public final int mPlayerType;
 
-        public final static int AUDIO_ATTRIBUTES_NONE = 0;
-        public final static int AUDIO_ATTRIBUTES_DEFINED = 1;
+        public static final int AUDIO_ATTRIBUTES_NONE = 0;
+        public static final int AUDIO_ATTRIBUTES_DEFINED = 1;
         public final AudioAttributes mAttributes;
         public final IPlayer mIPlayer;