AudioService: move volume callback on AudioService

Robustness to crash of AudioServer.
Take benefit of future permission enforcement.

Bug: 293236285
Flag: EXEMPT refactor
Test: atest com.android.server.audio

Signed-off-by: Francois Gaffie <francois.gaffie@renault.com>
Change-Id: If556a668f45d608b98b6e8073426f5bb8128c7a2

6 files changed, 112 insertions, 402 deletions

diff --git a/media/java/android/media/AudioManager.java b/media/java/android/media/AudioManager.java
index 4aba491c291e..f0890d11c95e 100644
--- a/media/java/android/media/AudioManager.java
+++ b/media/java/android/media/AudioManager.java
@@ -65,7 +65,7 @@ import android.media.audiopolicy.AudioPolicy;
 import android.media.audiopolicy.AudioPolicy.AudioPolicyFocusListener;
 import android.media.audiopolicy.AudioProductStrategy;
 import android.media.audiopolicy.AudioVolumeGroup;
-import android.media.audiopolicy.AudioVolumeGroupChangeHandler;
+import android.media.audiopolicy.IAudioVolumeChangeDispatcher;
 import android.media.projection.MediaProjection;
 import android.media.session.MediaController;
 import android.media.session.MediaSession;
@@ -128,8 +128,6 @@ public class AudioManager {
     private static final String TAG = "AudioManager";
     private static final boolean DEBUG = false;
     private static final AudioPortEventHandler sAudioPortEventHandler = new AudioPortEventHandler();
-    private static final AudioVolumeGroupChangeHandler sAudioAudioVolumeGroupChangedHandler =
-            new AudioVolumeGroupChangeHandler();
 
     private static WeakReference<Context> sContext;
 
@@ -8761,9 +8759,13 @@ public class AudioManager {
         }
     }
 
+    //====================================================================
+    // Notification of volume group changes
     /**
+     * Callback to receive updates on volume group changes, register using
+     * {@link AudioManager#registerVolumeGroupCallback(Executor, AudioVolumeCallback)}.
+     *
      * @hide
-     * Callback registered by client to be notified upon volume group change.
      */
     @SystemApi
     public abstract static class VolumeGroupCallback {
@@ -8774,35 +8776,63 @@ public class AudioManager {
         public void onAudioVolumeGroupChanged(int group, int flags) {}
     }
 
-   /**
-    * @hide
-    * Register an audio volume group change listener.
-    * @param callback the {@link VolumeGroupCallback} to register
-    */
+    /**
+     * @hide
+     * Register an audio volume group change listener.
+     *
+     * @param executor {@link Executor} to handle the callbacks
+     * @param callback the callback to receive the audio volume group changes
+     * @throws SecurityException if the caller doesn't have the required permission.
+     */
     @SystemApi
-    public void registerVolumeGroupCallback(
-            @NonNull Executor executor,
+    public void registerVolumeGroupCallback(@NonNull Executor executor,
             @NonNull VolumeGroupCallback callback) {
-        Preconditions.checkNotNull(executor, "executor must not be null");
-        Preconditions.checkNotNull(callback, "volume group change cb must not be null");
-        sAudioAudioVolumeGroupChangedHandler.init();
-        // TODO: make use of executor
-        sAudioAudioVolumeGroupChangedHandler.registerListener(callback);
+        mVolumeChangedListenerMgr.addListener(executor, callback, "registerVolumeGroupCallback",
+                () -> new AudioVolumeChangeDispatcherStub());
     }
 
-   /**
-    * @hide
-    * Unregister an audio volume group change listener.
-    * @param callback the {@link VolumeGroupCallback} to unregister
-    */
+    /**
+     * @hide
+     * Unregister an audio volume group change listener.
+     * @param callback the {@link VolumeGroupCallback} to unregister
+     */
     @SystemApi
-    public void unregisterVolumeGroupCallback(
-            @NonNull VolumeGroupCallback callback) {
-        Preconditions.checkNotNull(callback, "volume group change cb must not be null");
-        sAudioAudioVolumeGroupChangedHandler.unregisterListener(callback);
+    public void unregisterVolumeGroupCallback(@NonNull VolumeGroupCallback callback) {
+        mVolumeChangedListenerMgr.removeListener(callback, "unregisterVolumeGroupCallback");
     }
 
     /**
+     * Manages the VolumeGroupCallback listeners and the AudioVolumeChangeDispatcherStub
+     */
+    private final CallbackUtil.LazyListenerManager<VolumeGroupCallback> mVolumeChangedListenerMgr =
+            new CallbackUtil.LazyListenerManager();
+
+    final class AudioVolumeChangeDispatcherStub extends IAudioVolumeChangeDispatcher.Stub
+            implements CallbackUtil.DispatcherStub {
+
+        @Override
+        public void register(boolean register) {
+            try {
+                if (register) {
+                    getService().registerAudioVolumeCallback(this);
+                } else {
+                    getService().unregisterAudioVolumeCallback(this);
+                }
+            } catch (RemoteException e) {
+                e.rethrowFromSystemServer();
+            }
+        }
+
+        @Override
+        public void onAudioVolumeGroupChanged(int group, int flags) {
+            mVolumeChangedListenerMgr.callListeners((listener) ->
+                    listener.onAudioVolumeGroupChanged(group, flags));
+        }
+    }
+
+    //====================================================================
+
+    /**
      * Return if an asset contains haptic channels or not.
      *
      * @param context the {@link Context} to resolve the uri.
diff --git a/media/java/android/media/AudioSystem.java b/media/java/android/media/AudioSystem.java
index ad6f2e52fd97..4906cd3fb1e5 100644
--- a/media/java/android/media/AudioSystem.java
+++ b/media/java/android/media/AudioSystem.java
@@ -2732,4 +2732,25 @@ public class AudioSystem
      * @hide
      */
     public static native void triggerSystemPropertyUpdate(long handle);
+
+    /**
+     * Registers the given {@link INativeAudioVolumeGroupCallback} to native audioserver.
+     * @param callback to register
+     * @return {@link #SUCCESS} if successfully registered.
+     *
+     * @hide
+     */
+    public static native int registerAudioVolumeGroupCallback(
+            INativeAudioVolumeGroupCallback callback);
+
+    /**
+     * Unegisters the given {@link INativeAudioVolumeGroupCallback} from native audioserver
+     * previously registered via {@link #registerAudioVolumeGroupCallback}.
+     * @param callback to register
+     * @return {@link #SUCCESS} if successfully registered.
+     *
+     * @hide
+     */
+    public static native int unregisterAudioVolumeGroupCallback(
+            INativeAudioVolumeGroupCallback callback);
 }
diff --git a/media/java/android/media/IAudioService.aidl b/media/java/android/media/IAudioService.aidl
index 8aadb418cf5a..b97b943113b6 100644
--- a/media/java/android/media/IAudioService.aidl
+++ b/media/java/android/media/IAudioService.aidl
@@ -65,6 +65,7 @@ import android.media.audiopolicy.AudioPolicyConfig;
 import android.media.audiopolicy.AudioProductStrategy;
 import android.media.audiopolicy.AudioVolumeGroup;
 import android.media.audiopolicy.IAudioPolicyCallback;
+import android.media.audiopolicy.IAudioVolumeChangeDispatcher;
 import android.media.projection.IMediaProjection;
 import android.net.Uri;
 import android.os.PersistableBundle;
@@ -446,6 +447,10 @@ interface IAudioService {
 
     boolean isAudioServerRunning();
 
+    void registerAudioVolumeCallback(IAudioVolumeChangeDispatcher avc);
+
+    oneway void unregisterAudioVolumeCallback(IAudioVolumeChangeDispatcher avc);
+
     int setUidDeviceAffinity(in IAudioPolicyCallback pcb, in int uid, in int[] deviceTypes,
              in String[] deviceAddresses);
 
diff --git a/media/java/android/media/audiopolicy/AudioVolumeGroupChangeHandler.java b/media/java/android/media/audiopolicy/AudioVolumeGroupChangeHandler.java
deleted file mode 100644
index 022cfeeb4e43..000000000000
--- a/media/java/android/media/audiopolicy/AudioVolumeGroupChangeHandler.java
+++ /dev/null
@@ -1,166 +0,0 @@
-/*
- * Copyright (C) 2018 The Android Open Source Project
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *      http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-
-package android.media.audiopolicy;
-
-import android.annotation.NonNull;
-import android.media.AudioManager;
-import android.os.Handler;
-import android.os.HandlerThread;
-import android.os.Message;
-
-import com.android.internal.util.Preconditions;
-
-import java.lang.ref.WeakReference;
-import java.util.ArrayList;
-
-/**
- * The AudioVolumeGroupChangeHandler handles AudioManager.OnAudioVolumeGroupChangedListener
- * callbacks posted from JNI
- *
- * TODO: Make use of Executor of callbacks.
- * @hide
- */
-public class AudioVolumeGroupChangeHandler {
-    private Handler mHandler;
-    private HandlerThread mHandlerThread;
-    private final ArrayList<AudioManager.VolumeGroupCallback> mListeners =
-            new ArrayList<AudioManager.VolumeGroupCallback>();
-
-    private static final String TAG = "AudioVolumeGroupChangeHandler";
-
-    private static final int AUDIOVOLUMEGROUP_EVENT_VOLUME_CHANGED = 1000;
-    private static final int AUDIOVOLUMEGROUP_EVENT_NEW_LISTENER = 4;
-
-    /**
-     * Accessed by native methods: JNI Callback context.
-     */
-    @SuppressWarnings("unused")
-    private long mJniCallback;
-
-    /**
-     * Initialization
-     */
-    public void init() {
-        synchronized (this) {
-            if (mHandler != null) {
-                return;
-            }
-            // create a new thread for our new event handler
-            mHandlerThread = new HandlerThread(TAG);
-            mHandlerThread.start();
-
-            if (mHandlerThread.getLooper() == null) {
-                mHandler = null;
-                return;
-            }
-            mHandler = new Handler(mHandlerThread.getLooper()) {
-                @Override
-                public void handleMessage(Message msg) {
-                    ArrayList<AudioManager.VolumeGroupCallback> listeners;
-                    synchronized (this) {
-                        if (msg.what == AUDIOVOLUMEGROUP_EVENT_NEW_LISTENER) {
-                            listeners =
-                                    new ArrayList<AudioManager.VolumeGroupCallback>();
-                            if (mListeners.contains(msg.obj)) {
-                                listeners.add(
-                                        (AudioManager.VolumeGroupCallback) msg.obj);
-                            }
-                        } else {
-                            listeners = (ArrayList<AudioManager.VolumeGroupCallback>)
-                                    mListeners.clone();
-                        }
-                    }
-                    if (listeners.isEmpty()) {
-                        return;
-                    }
-
-                    switch (msg.what) {
-                        case AUDIOVOLUMEGROUP_EVENT_VOLUME_CHANGED:
-                            for (int i = 0; i < listeners.size(); i++) {
-                                listeners.get(i).onAudioVolumeGroupChanged((int) msg.arg1,
-                                                                           (int) msg.arg2);
-                            }
-                            break;
-
-                        default:
-                            break;
-                    }
-                }
-            };
-            native_setup(new WeakReference<AudioVolumeGroupChangeHandler>(this));
-        }
-    }
-
-    private native void native_setup(Object moduleThis);
-
-    @Override
-    protected void finalize() {
-        native_finalize();
-        if (mHandlerThread.isAlive()) {
-            mHandlerThread.quit();
-        }
-    }
-    private native void native_finalize();
-
-   /**
-    * @param cb the {@link AudioManager.VolumeGroupCallback} to register
-    */
-    public void registerListener(@NonNull AudioManager.VolumeGroupCallback cb) {
-        Preconditions.checkNotNull(cb, "volume group callback shall not be null");
-        synchronized (this) {
-            mListeners.add(cb);
-        }
-        if (mHandler != null) {
-            Message m = mHandler.obtainMessage(
-                    AUDIOVOLUMEGROUP_EVENT_NEW_LISTENER, 0, 0, cb);
-            mHandler.sendMessage(m);
-        }
-    }
-
-   /**
-    * @param cb the {@link AudioManager.VolumeGroupCallback} to unregister
-    */
-    public void unregisterListener(@NonNull AudioManager.VolumeGroupCallback cb) {
-        Preconditions.checkNotNull(cb, "volume group callback shall not be null");
-        synchronized (this) {
-            mListeners.remove(cb);
-        }
-    }
-
-    Handler handler() {
-        return mHandler;
-    }
-
-    @SuppressWarnings("unused")
-    private static void postEventFromNative(Object moduleRef,
-                                            int what, int arg1, int arg2, Object obj) {
-        AudioVolumeGroupChangeHandler eventHandler =
-                (AudioVolumeGroupChangeHandler) ((WeakReference) moduleRef).get();
-        if (eventHandler == null) {
-            return;
-        }
-
-        if (eventHandler != null) {
-            Handler handler = eventHandler.handler();
-            if (handler != null) {
-                Message m = handler.obtainMessage(what, arg1, arg2, obj);
-                // Do not remove previous messages, as we would lose notification of group changes
-                handler.sendMessage(m);
-            }
-        }
-    }
-}
diff --git a/media/java/android/media/audiopolicy/IAudioVolumeChangeDispatcher.aidl b/media/java/android/media/audiopolicy/IAudioVolumeChangeDispatcher.aidl
new file mode 100644
index 000000000000..e6f9024cfd1e
--- /dev/null
+++ b/media/java/android/media/audiopolicy/IAudioVolumeChangeDispatcher.aidl
@@ -0,0 +1,31 @@
+/* Copyright (C) 2025 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package android.media.audiopolicy;
+
+/**
+ * AIDL for the AudioService to signal audio volume groups changes
+ *
+ * {@hide}
+ */
+oneway interface IAudioVolumeChangeDispatcher {
+
+    /**
+     * Called when a volume group has been changed
+     * @param group id of the volume group that has changed.
+     * @param flags one or more flags to describe the volume change.
+     */
+    void onAudioVolumeGroupChanged(int group, int flags);
+}
diff --git a/media/tests/AudioPolicyTest/src/com/android/audiopolicytest/AudioVolumeGroupChangeHandlerTest.java b/media/tests/AudioPolicyTest/src/com/android/audiopolicytest/AudioVolumeGroupChangeHandlerTest.java
deleted file mode 100644
index 82394a2eb420..000000000000
--- a/media/tests/AudioPolicyTest/src/com/android/audiopolicytest/AudioVolumeGroupChangeHandlerTest.java
+++ /dev/null
@@ -1,211 +0,0 @@
-/*
- * Copyright (C) 2020 The Android Open Source Project
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *      http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-
-package com.android.audiopolicytest;
-
-import static androidx.test.core.app.ApplicationProvider.getApplicationContext;
-
-import static com.android.audiopolicytest.AudioVolumeTestUtil.DEFAULT_ATTRIBUTES;
-import static com.android.audiopolicytest.AudioVolumeTestUtil.incrementVolumeIndex;
-
-import static org.junit.Assert.assertEquals;
-import static org.junit.Assert.assertThrows;
-import static org.junit.Assert.assertTrue;
-
-import android.media.AudioAttributes;
-import android.media.AudioManager;
-import android.media.audiopolicy.AudioVolumeGroup;
-import android.media.audiopolicy.AudioVolumeGroupChangeHandler;
-import android.platform.test.annotations.Presubmit;
-
-import androidx.test.ext.junit.runners.AndroidJUnit4;
-
-import org.junit.Before;
-import org.junit.Rule;
-import org.junit.Test;
-import org.junit.runner.RunWith;
-
-import java.util.ArrayList;
-import java.util.List;
-
-@Presubmit
-@RunWith(AndroidJUnit4.class)
-public class AudioVolumeGroupChangeHandlerTest {
-    private static final String TAG = "AudioVolumeGroupChangeHandlerTest";
-
-    @Rule
-    public final AudioVolumesTestRule rule = new AudioVolumesTestRule();
-
-    private AudioManager mAudioManager;
-
-    @Before
-    public void setUp() {
-        mAudioManager = getApplicationContext().getSystemService(AudioManager.class);
-    }
-
-    @Test
-    public void testRegisterInvalidCallback() {
-        final AudioVolumeGroupChangeHandler audioAudioVolumeGroupChangedHandler =
-                new AudioVolumeGroupChangeHandler();
-
-        audioAudioVolumeGroupChangedHandler.init();
-
-        assertThrows(NullPointerException.class, () -> {
-            AudioManager.VolumeGroupCallback nullCb = null;
-            audioAudioVolumeGroupChangedHandler.registerListener(nullCb);
-        });
-    }
-
-    @Test
-    public void testUnregisterInvalidCallback() {
-        final AudioVolumeGroupChangeHandler audioAudioVolumeGroupChangedHandler =
-                new AudioVolumeGroupChangeHandler();
-
-        audioAudioVolumeGroupChangedHandler.init();
-
-        final AudioVolumeGroupCallbackHelper cb = new AudioVolumeGroupCallbackHelper();
-        audioAudioVolumeGroupChangedHandler.registerListener(cb);
-
-        assertThrows(NullPointerException.class, () -> {
-            AudioManager.VolumeGroupCallback nullCb = null;
-            audioAudioVolumeGroupChangedHandler.unregisterListener(nullCb);
-        });
-        audioAudioVolumeGroupChangedHandler.unregisterListener(cb);
-    }
-
-    @Test
-    public void testRegisterUnregisterCallback() {
-        final AudioVolumeGroupChangeHandler audioAudioVolumeGroupChangedHandler =
-                new AudioVolumeGroupChangeHandler();
-
-        audioAudioVolumeGroupChangedHandler.init();
-        final AudioVolumeGroupCallbackHelper validCb = new AudioVolumeGroupCallbackHelper();
-
-        // Should not assert, otherwise test will fail
-        audioAudioVolumeGroupChangedHandler.registerListener(validCb);
-
-        // Should not assert, otherwise test will fail
-        audioAudioVolumeGroupChangedHandler.unregisterListener(validCb);
-    }
-
-    @Test
-    public void testCallbackReceived() {
-        final AudioVolumeGroupChangeHandler audioAudioVolumeGroupChangedHandler =
-                new AudioVolumeGroupChangeHandler();
-
-        audioAudioVolumeGroupChangedHandler.init();
-
-        final AudioVolumeGroupCallbackHelper validCb = new AudioVolumeGroupCallbackHelper();
-        audioAudioVolumeGroupChangedHandler.registerListener(validCb);
-
-        List<AudioVolumeGroup> audioVolumeGroups = mAudioManager.getAudioVolumeGroups();
-        assertTrue(audioVolumeGroups.size() > 0);
-
-        try {
-            for (final AudioVolumeGroup audioVolumeGroup : audioVolumeGroups) {
-                int volumeGroupId = audioVolumeGroup.getId();
-
-                List<AudioAttributes> avgAttributes = audioVolumeGroup.getAudioAttributes();
-                // Set the volume per attributes (if valid) and wait the callback
-                if (avgAttributes.size() == 0 || avgAttributes.get(0).equals(DEFAULT_ATTRIBUTES)) {
-                    // Some volume groups may not have valid attributes, used for internal
-                    // volume management like patch/rerouting
-                    // so bailing out strategy retrieval from attributes
-                    continue;
-                }
-                final AudioAttributes aa = avgAttributes.get(0);
-
-                int index = mAudioManager.getVolumeIndexForAttributes(aa);
-                int indexMax = mAudioManager.getMaxVolumeIndexForAttributes(aa);
-                int indexMin = mAudioManager.getMinVolumeIndexForAttributes(aa);
-
-                final int indexForAa = incrementVolumeIndex(index, indexMin, indexMax);
-
-                // Set the receiver to filter only the current group callback
-                validCb.setExpectedVolumeGroup(volumeGroupId);
-                mAudioManager.setVolumeIndexForAttributes(aa, indexForAa, 0/*flags*/);
-                assertTrue(validCb.waitForExpectedVolumeGroupChanged(
-                        AudioVolumeGroupCallbackHelper.ASYNC_TIMEOUT_MS));
-
-                final int readIndex = mAudioManager.getVolumeIndexForAttributes(aa);
-                assertEquals(readIndex, indexForAa);
-            }
-        } finally {
-            audioAudioVolumeGroupChangedHandler.unregisterListener(validCb);
-        }
-    }
-
-    @Test
-    public void testMultipleCallbackReceived() {
-
-        final AudioVolumeGroupChangeHandler audioAudioVolumeGroupChangedHandler =
-                new AudioVolumeGroupChangeHandler();
-
-        audioAudioVolumeGroupChangedHandler.init();
-
-        final int callbackCount = 10;
-        final List<AudioVolumeGroupCallbackHelper> validCbs =
-                new ArrayList<AudioVolumeGroupCallbackHelper>();
-        for (int i = 0; i < callbackCount; i++) {
-            validCbs.add(new AudioVolumeGroupCallbackHelper());
-        }
-        for (final AudioVolumeGroupCallbackHelper cb : validCbs) {
-            audioAudioVolumeGroupChangedHandler.registerListener(cb);
-        }
-
-        List<AudioVolumeGroup> audioVolumeGroups = mAudioManager.getAudioVolumeGroups();
-        assertTrue(audioVolumeGroups.size() > 0);
-
-        try {
-            for (final AudioVolumeGroup audioVolumeGroup : audioVolumeGroups) {
-                int volumeGroupId = audioVolumeGroup.getId();
-
-                List<AudioAttributes> avgAttributes = audioVolumeGroup.getAudioAttributes();
-                // Set the volume per attributes (if valid) and wait the callback
-                if (avgAttributes.size() == 0 || avgAttributes.get(0).equals(DEFAULT_ATTRIBUTES)) {
-                    // Some volume groups may not have valid attributes, used for internal
-                    // volume management like patch/rerouting
-                    // so bailing out strategy retrieval from attributes
-                    continue;
-                }
-                AudioAttributes aa = avgAttributes.get(0);
-
-                int index = mAudioManager.getVolumeIndexForAttributes(aa);
-                int indexMax = mAudioManager.getMaxVolumeIndexForAttributes(aa);
-                int indexMin = mAudioManager.getMinVolumeIndexForAttributes(aa);
-
-                final int indexForAa = incrementVolumeIndex(index, indexMin, indexMax);
-
-                // Set the receiver to filter only the current group callback
-                for (final AudioVolumeGroupCallbackHelper cb : validCbs) {
-                    cb.setExpectedVolumeGroup(volumeGroupId);
-                }
-                mAudioManager.setVolumeIndexForAttributes(aa, indexForAa, 0/*flags*/);
-
-                for (final AudioVolumeGroupCallbackHelper cb : validCbs) {
-                    assertTrue(cb.waitForExpectedVolumeGroupChanged(
-                            AudioVolumeGroupCallbackHelper.ASYNC_TIMEOUT_MS));
-                }
-                int readIndex = mAudioManager.getVolumeIndexForAttributes(aa);
-                assertEquals(readIndex, indexForAa);
-            }
-        } finally {
-            for (final AudioVolumeGroupCallbackHelper cb : validCbs) {
-                audioAudioVolumeGroupChangedHandler.unregisterListener(cb);
-            }
-        }
-    }
-}