Merge "MediaSessionManager: Add listener for Session2Token changes"
diff --git a/Android.bp b/Android.bp
index 980aa04..7e97e66 100644
--- a/Android.bp
+++ b/Android.bp
@@ -502,6 +502,7 @@
         "media/java/android/media/session/IOnMediaKeyListener.aidl",
         "media/java/android/media/session/IOnVolumeKeyLongPressListener.aidl",
         "media/java/android/media/session/ISession.aidl",
+        "media/java/android/media/session/ISession2TokensListener.aidl",
         "media/java/android/media/session/ISessionCallback.aidl",
         "media/java/android/media/session/ISessionController.aidl",
         "media/java/android/media/session/ISessionControllerCallback.aidl",
diff --git a/media/java/android/media/session/ISession2TokensListener.aidl b/media/java/android/media/session/ISession2TokensListener.aidl
new file mode 100644
index 0000000..7d1a4aa
--- /dev/null
+++ b/media/java/android/media/session/ISession2TokensListener.aidl
@@ -0,0 +1,27 @@
+/*
+ * Copyright 2019 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.session;
+
+import android.media.Session2Token;
+
+/**
+ * Listens for changes to the list of session2 tokens.
+ * @hide
+ */
+oneway interface ISession2TokensListener {
+    void onSession2TokensChanged(in List<Session2Token> tokens);
+}
diff --git a/media/java/android/media/session/ISessionManager.aidl b/media/java/android/media/session/ISessionManager.aidl
index 7ac3ef2..46516e0 100644
--- a/media/java/android/media/session/ISessionManager.aidl
+++ b/media/java/android/media/session/ISessionManager.aidl
@@ -23,6 +23,7 @@
 import android.media.session.IOnMediaKeyListener;
 import android.media.session.IOnVolumeKeyLongPressListener;
 import android.media.session.ISession;
+import android.media.session.ISession2TokensListener;
 import android.media.session.SessionCallbackLink;
 import android.os.Bundle;
 import android.view.KeyEvent;
@@ -45,6 +46,8 @@
     void addSessionsListener(in IActiveSessionsListener listener, in ComponentName compName,
             int userId);
     void removeSessionsListener(in IActiveSessionsListener listener);
+    void addSession2TokensListener(in ISession2TokensListener listener, int userId);
+    void removeSession2TokensListener(in ISession2TokensListener listener);
 
     // This is for the system volume UI only
     void setRemoteVolumeController(in IRemoteVolumeController rvc);
@@ -56,6 +59,5 @@
     void setOnVolumeKeyLongPressListener(in IOnVolumeKeyLongPressListener listener);
     void setOnMediaKeyListener(in IOnMediaKeyListener listener);
 
-    // MediaSession2
     boolean isTrusted(String controllerPackageName, int controllerPid, int controllerUid);
 }
diff --git a/media/java/android/media/session/MediaSessionManager.java b/media/java/android/media/session/MediaSessionManager.java
index 56ea484..4596c22 100644
--- a/media/java/android/media/session/MediaSessionManager.java
+++ b/media/java/android/media/session/MediaSessionManager.java
@@ -41,6 +41,8 @@
 import android.util.Log;
 import android.view.KeyEvent;
 
+import com.android.internal.annotations.GuardedBy;
+
 import java.util.ArrayList;
 import java.util.List;
 import java.util.Objects;
@@ -69,9 +71,13 @@
      */
     public static final int RESULT_MEDIA_KEY_HANDLED = 1;
 
+    private final Object mLock = new Object();
+    @GuardedBy("mLock")
     private final ArrayMap<OnActiveSessionsChangedListener, SessionsChangedWrapper> mListeners
             = new ArrayMap<OnActiveSessionsChangedListener, SessionsChangedWrapper>();
-    private final Object mLock = new Object();
+    @GuardedBy("mLock")
+    private final ArrayMap<OnSession2TokensChangedListener, Session2TokensChangedWrapper>
+            mSession2TokensListeners = new ArrayMap<>();
     private final ISessionManager mService;
 
     private Context mContext;
@@ -324,6 +330,87 @@
     }
 
     /**
+     * Adds a listener to be notified when the {@link #getSession2Tokens()} changes.
+     * <p>
+     * This API is not generally intended for third party application developers.
+     * Use the <a href="{@docRoot}jetpack/androidx.html">AndroidX</a>
+     * <a href="{@docRoot}reference/androidx/media2/package-summary.html">Media2 Library</a>
+     * for consistent behavior across all devices.
+     *
+     * @param listener The listener to add
+     * @param handler The handler to call listener on. If {@code null}, calling thread's looper will
+     *                be used.
+     * @hide
+     */
+    // TODO(jaewan): Unhide
+    public void addOnSession2TokensChangedListener(
+            @NonNull OnSession2TokensChangedListener listener, @Nullable Handler handler) {
+        addOnSession2TokensChangedListener(UserHandle.myUserId(), listener, handler);
+    }
+
+    /**
+     * Adds a listener to be notified when the {@link #getSession2Tokens()} changes.
+     * <p>
+     * This API is not generally intended for third party application developers.
+     * Use the <a href="{@docRoot}jetpack/androidx.html">AndroidX</a>
+     * <a href="{@docRoot}reference/androidx/media2/package-summary.html">Media2 Library</a>
+     * for consistent behavior across all devices.
+     *
+     * @param userId The userId to listen for changes on
+     * @param listener The listener to add
+     * @param handler The handler to call listener on. If {@code null}, calling thread's looper will
+     *                be used.
+     * @hide
+     */
+    public void addOnSession2TokensChangedListener(int userId,
+            @NonNull OnSession2TokensChangedListener listener, @Nullable Handler handler) {
+        if (listener == null) {
+            throw new IllegalArgumentException("listener shouldn't be null");
+        }
+        synchronized (mLock) {
+            if (mSession2TokensListeners.get(listener) != null) {
+                Log.w(TAG, "Attempted to add session listener twice, ignoring.");
+                return;
+            }
+            Session2TokensChangedWrapper wrapper =
+                    new Session2TokensChangedWrapper(listener, handler);
+            try {
+                mService.addSession2TokensListener(wrapper.getStub(), userId);
+                mSession2TokensListeners.put(listener, wrapper);
+            } catch (RemoteException e) {
+                Log.e(TAG, "Error in addSessionTokensListener.", e);
+                e.rethrowFromSystemServer();
+            }
+        }
+    }
+
+    /**
+     * Removes the {@link OnSession2TokensChangedListener} to stop receiving session token updates.
+     *
+     * @param listener The listener to remove.
+     * @hide
+     */
+    // TODO(jaewan): Unhide
+    public void removeOnSession2TokensChangedListener(
+            @NonNull OnSession2TokensChangedListener listener) {
+        if (listener == null) {
+            throw new IllegalArgumentException("listener may not be null");
+        }
+        final Session2TokensChangedWrapper wrapper;
+        synchronized (mLock) {
+            wrapper = mSession2TokensListeners.remove(listener);
+        }
+        if (wrapper != null) {
+            try {
+                mService.removeSession2TokensListener(wrapper.getStub());
+            } catch (RemoteException e) {
+                Log.e(TAG, "Error in removeSessionTokensListener.", e);
+                e.rethrowFromSystemServer();
+            }
+        }
+    }
+
+    /**
      * Set the remote volume controller to receive volume updates on. Only for
      * use by system UI.
      *
@@ -590,6 +677,26 @@
     }
 
     /**
+     * Listens for changes to the {@link #getSession2Tokens()}. This can be added
+     * using {@link #addOnSession2TokensChangedListener(OnSession2TokensChangedListener, Handler)}.
+     * <p>
+     * This API is not generally intended for third party application developers.
+     * Use the <a href="{@docRoot}jetpack/androidx.html">AndroidX</a>
+     * <a href="{@docRoot}reference/androidx/media2/package-summary.html">Media2 Library</a>
+     * for consistent behavior across all devices.
+     *
+     * @hide
+     */
+    public interface OnSession2TokensChangedListener {
+        /**
+         * Called when the {@link #getSession2Tokens()} is changed.
+         *
+         * @param tokens list of {@link Session2Token}
+         */
+        void onSession2TokensChanged(@NonNull List<Session2Token> tokens);
+    }
+
+    /**
      * Listens the volume key long-presses.
      * @hide
      */
@@ -807,6 +914,27 @@
         }
     }
 
+    private static final class Session2TokensChangedWrapper {
+        private final OnSession2TokensChangedListener mListener;
+        private final Handler mHandler;
+        private final ISession2TokensListener.Stub mStub =
+                new ISession2TokensListener.Stub() {
+                    @Override
+                    public void onSession2TokensChanged(final List<Session2Token> tokens) {
+                        mHandler.post(() -> mListener.onSession2TokensChanged(tokens));
+                    }
+                };
+
+        Session2TokensChangedWrapper(OnSession2TokensChangedListener listener, Handler handler) {
+            mListener = listener;
+            mHandler = (handler == null) ? new Handler() : new Handler(handler.getLooper());
+        }
+
+        public ISession2TokensListener.Stub getStub() {
+            return mStub;
+        }
+    }
+
     private static final class OnVolumeKeyLongPressListenerImpl
             extends IOnVolumeKeyLongPressListener.Stub {
         private OnVolumeKeyLongPressListener mListener;
diff --git a/services/core/java/com/android/server/media/MediaSessionService.java b/services/core/java/com/android/server/media/MediaSessionService.java
index ce0e72b..ba7b87e 100644
--- a/services/core/java/com/android/server/media/MediaSessionService.java
+++ b/services/core/java/com/android/server/media/MediaSessionService.java
@@ -16,6 +16,8 @@
 
 package com.android.server.media;
 
+import static android.os.UserHandle.USER_ALL;
+
 import android.annotation.Nullable;
 import android.app.ActivityManager;
 import android.app.INotificationManager;
@@ -48,6 +50,7 @@
 import android.media.session.IOnMediaKeyListener;
 import android.media.session.IOnVolumeKeyLongPressListener;
 import android.media.session.ISession;
+import android.media.session.ISession2TokensListener;
 import android.media.session.ISessionManager;
 import android.media.session.MediaSession;
 import android.media.session.MediaSessionManager;
@@ -119,6 +122,9 @@
     //       one place.
     @GuardedBy("mLock")
     private final SparseArray<List<Session2Token>> mSession2TokensPerUser = new SparseArray<>();
+    @GuardedBy("mLock")
+    private final List<Session2TokensListenerRecord> mSession2TokensListenerRecords =
+            new ArrayList<>();
 
     private KeyguardManager mKeyguardManager;
     private IAudioService mAudioService;
@@ -235,7 +241,7 @@
 
     private List<MediaSessionRecord> getActiveSessionsLocked(int userId) {
         List<MediaSessionRecord> records = new ArrayList<>();
-        if (userId == UserHandle.USER_ALL) {
+        if (userId == USER_ALL) {
             int size = mUserRecords.size();
             for (int i = 0; i < size; i++) {
                 records.addAll(mUserRecords.valueAt(i).mPriorityStack.getActiveSessions(userId));
@@ -251,13 +257,24 @@
 
         // Return global priority session at the first whenever it's asked.
         if (isGlobalPriorityActiveLocked()
-                && (userId == UserHandle.USER_ALL
-                    || userId == mGlobalPrioritySession.getUserId())) {
+                && (userId == USER_ALL || userId == mGlobalPrioritySession.getUserId())) {
             records.add(0, mGlobalPrioritySession);
         }
         return records;
     }
 
+    List<Session2Token> getSession2TokensLocked(int userId) {
+        List<Session2Token> list = new ArrayList<>();
+        if (userId == USER_ALL) {
+            for (int i = 0; i < mSession2TokensPerUser.size(); i++) {
+                list.addAll(mSession2TokensPerUser.valueAt(i));
+            }
+        } else {
+            list.addAll(mSession2TokensPerUser.get(userId));
+        }
+        return list;
+    }
+
     /**
      * Tells the system UI that volume has changed on an active remote session.
      */
@@ -316,7 +333,7 @@
             FullUserRecord user = getFullUserRecordLocked(userId);
             if (user != null) {
                 if (user.mFullUserId == userId) {
-                    user.destroySessionsForUserLocked(UserHandle.USER_ALL);
+                    user.destroySessionsForUserLocked(USER_ALL);
                     mUserRecords.remove(userId);
                 } else {
                     user.destroySessionsForUserLocked(userId);
@@ -393,14 +410,14 @@
             for (int i = mSessionsListeners.size() - 1; i >= 0; i--) {
                 SessionsListenerRecord listener = mSessionsListeners.get(i);
                 try {
-                    enforceMediaPermissions(listener.mComponentName, listener.mPid, listener.mUid,
-                            listener.mUserId);
+                    enforceMediaPermissions(listener.componentName, listener.pid, listener.uid,
+                            listener.userId);
                 } catch (SecurityException e) {
-                    Log.i(TAG, "ActiveSessionsListener " + listener.mComponentName
+                    Log.i(TAG, "ActiveSessionsListener " + listener.componentName
                             + " is no longer authorized. Disconnecting.");
                     mSessionsListeners.remove(i);
                     try {
-                        listener.mListener
+                        listener.listener
                                 .onActiveSessionsChanged(new ArrayList<MediaSession.Token>());
                     } catch (Exception e1) {
                         // ignore
@@ -562,13 +579,23 @@
 
     private int findIndexOfSessionsListenerLocked(IActiveSessionsListener listener) {
         for (int i = mSessionsListeners.size() - 1; i >= 0; i--) {
-            if (mSessionsListeners.get(i).mListener.asBinder() == listener.asBinder()) {
+            if (mSessionsListeners.get(i).listener.asBinder() == listener.asBinder()) {
                 return i;
             }
         }
         return -1;
     }
 
+    private int findIndexOfSession2TokensListenerLocked(ISession2TokensListener listener) {
+        for (int i = mSession2TokensListenerRecords.size() - 1; i >= 0; i--) {
+            if (mSession2TokensListenerRecords.get(i).listener.asBinder() == listener.asBinder()) {
+                return i;
+            }
+        }
+        return -1;
+    }
+
+
     private void pushSessionsChanged(int userId) {
         synchronized (mLock) {
             FullUserRecord user = getFullUserRecordLocked(userId);
@@ -585,9 +612,9 @@
             pushRemoteVolumeUpdateLocked(userId);
             for (int i = mSessionsListeners.size() - 1; i >= 0; i--) {
                 SessionsListenerRecord record = mSessionsListeners.get(i);
-                if (record.mUserId == UserHandle.USER_ALL || record.mUserId == userId) {
+                if (record.userId == USER_ALL || record.userId == userId) {
                     try {
-                        record.mListener.onActiveSessionsChanged(tokens);
+                        record.listener.onActiveSessionsChanged(tokens);
                     } catch (RemoteException e) {
                         Log.w(TAG, "Dead ActiveSessionsListener in pushSessionsChanged, removing",
                                 e);
@@ -614,6 +641,25 @@
         }
     }
 
+    void pushSession2TokensChangedLocked(int userId) {
+        List<Session2Token> allSession2Tokens = getSession2TokensLocked(USER_ALL);
+        List<Session2Token> session2Tokens = getSession2TokensLocked(userId);
+
+        for (int i = mSession2TokensListenerRecords.size() - 1; i >= 0; i--) {
+            Session2TokensListenerRecord listenerRecord = mSession2TokensListenerRecords.get(i);
+            try {
+                if (listenerRecord.userId == USER_ALL) {
+                    listenerRecord.listener.onSession2TokensChanged(allSession2Tokens);
+                } else if (listenerRecord.userId == userId) {
+                    listenerRecord.listener.onSession2TokensChanged(session2Tokens);
+                }
+            } catch (RemoteException e) {
+                Log.w(TAG, "Failed to notify Session2Token change. Removing listener.", e);
+                mSession2TokensListenerRecords.remove(i);
+            }
+        }
+    }
+
     /**
      * Called when the media button receiver for the {@param record} is changed.
      *
@@ -855,20 +901,20 @@
     }
 
     final class SessionsListenerRecord implements IBinder.DeathRecipient {
-        private final IActiveSessionsListener mListener;
-        private final ComponentName mComponentName;
-        private final int mUserId;
-        private final int mPid;
-        private final int mUid;
+        public final IActiveSessionsListener listener;
+        public final ComponentName componentName;
+        public final int userId;
+        public final int pid;
+        public final int uid;
 
         public SessionsListenerRecord(IActiveSessionsListener listener,
                 ComponentName componentName,
                 int userId, int pid, int uid) {
-            mListener = listener;
-            mComponentName = componentName;
-            mUserId = userId;
-            mPid = pid;
-            mUid = uid;
+            this.listener = listener;
+            this.componentName = componentName;
+            this.userId = userId;
+            this.pid = pid;
+            this.uid = uid;
         }
 
         @Override
@@ -879,6 +925,24 @@
         }
     }
 
+    final class Session2TokensListenerRecord implements IBinder.DeathRecipient {
+        public final ISession2TokensListener listener;
+        public final int userId;
+
+        Session2TokensListenerRecord(ISession2TokensListener listener,
+                int userId) {
+            this.listener = listener;
+            this.userId = userId;
+        }
+
+        @Override
+        public void binderDied() {
+            synchronized (mLock) {
+                mSession2TokensListenerRecords.remove(this);
+            }
+        }
+    }
+
     final class SettingsObserver extends ContentObserver {
         private final Uri mSecureSettingsUri = Settings.Secure.getUriFor(
                 Settings.Secure.ENABLED_NOTIFICATION_LISTENERS);
@@ -889,7 +953,7 @@
 
         private void observe() {
             mContentResolver.registerContentObserver(mSecureSettingsUri,
-                    false, this, UserHandle.USER_ALL);
+                    false, this, USER_ALL);
         }
 
         @Override
@@ -984,15 +1048,9 @@
                 int resolvedUserId = ActivityManager.handleIncomingUser(pid, uid, userId,
                         true /* allowAll */, true /* requireFull */, "getSession2Tokens",
                         null /* optional packageName */);
-                List<Session2Token> result = new ArrayList<>();
+                List<Session2Token> result;
                 synchronized (mLock) {
-                    if (resolvedUserId == UserHandle.USER_ALL) {
-                        for (int i = 0; i < mSession2TokensPerUser.size(); i++) {
-                            result.addAll(mSession2TokensPerUser.valueAt(i));
-                        }
-                    } else {
-                        result.addAll(mSession2TokensPerUser.get(userId));
-                    }
+                    result = getSession2TokensLocked(resolvedUserId);
                 }
                 return result;
             } finally {
@@ -1038,7 +1096,7 @@
                 if (index != -1) {
                     SessionsListenerRecord record = mSessionsListeners.remove(index);
                     try {
-                        record.mListener.asBinder().unlinkToDeath(record, 0);
+                        record.listener.asBinder().unlinkToDeath(record, 0);
                     } catch (Exception e) {
                         // ignore exceptions, the record is being removed
                     }
@@ -1046,6 +1104,56 @@
             }
         }
 
+        @Override
+        public void addSession2TokensListener(ISession2TokensListener listener,
+                int userId) {
+            final int pid = Binder.getCallingPid();
+            final int uid = Binder.getCallingUid();
+            final long token = Binder.clearCallingIdentity();
+
+            try {
+                // Check that they can make calls on behalf of the user and get the final user id.
+                int resolvedUserId = ActivityManager.handleIncomingUser(pid, uid, userId,
+                        true /* allowAll */, true /* requireFull */, "addSession2TokensListener",
+                        null /* optional packageName */);
+                synchronized (mLock) {
+                    int index = findIndexOfSession2TokensListenerLocked(listener);
+                    if (index >= 0) {
+                        Log.w(TAG, "addSession2TokensListener is already added, ignoring");
+                        return;
+                    }
+                    mSession2TokensListenerRecords.add(
+                            new Session2TokensListenerRecord(listener, resolvedUserId));
+                }
+            } finally {
+                Binder.restoreCallingIdentity(token);
+            }
+        }
+
+        @Override
+        public void removeSession2TokensListener(ISession2TokensListener listener) {
+            final int pid = Binder.getCallingPid();
+            final int uid = Binder.getCallingUid();
+            final long token = Binder.clearCallingIdentity();
+
+            try {
+                synchronized (mLock) {
+                    int index = findIndexOfSession2TokensListenerLocked(listener);
+                    if (index >= 0) {
+                        Session2TokensListenerRecord listenerRecord =
+                                mSession2TokensListenerRecords.remove(index);
+                        try {
+                            listenerRecord.listener.asBinder().unlinkToDeath(listenerRecord, 0);
+                        } catch (Exception e) {
+                            // Ignore exception.
+                        }
+                    }
+                }
+            } finally {
+                Binder.restoreCallingIdentity(token);
+            }
+        }
+
         /**
          * Handles the dispatching of the media button events to one of the
          * registered listeners, or if there was none, broadcast an
@@ -2012,6 +2120,7 @@
             synchronized (mLock) {
                 int userId = UserHandle.getUserId(mToken.getUid());
                 mSession2TokensPerUser.get(userId).add(mToken);
+                pushSession2TokensChangedLocked(userId);
             }
         }
 
@@ -2020,6 +2129,7 @@
             synchronized (mLock) {
                 int userId = UserHandle.getUserId(mToken.getUid());
                 mSession2TokensPerUser.get(userId).remove(mToken);
+                pushSession2TokensChangedLocked(userId);
             }
         }
     }