Minimum work to make volume handling work with sessions

This is the minimum change to make adjusting volume work with
MediaSessions. This only affects adjusting the volume and adjusting
the volume with a suggested stream. Adjusting a specific stream or
setting a specific stream will still use the same code.

This does not fix existing remote volume handling in RCC, which
will require a separate change to MediaController.

Change-Id: I5b957ff4bece1ee11e2364e1f216e1c08343c983
diff --git a/services/core/java/com/android/server/media/MediaSessionService.java b/services/core/java/com/android/server/media/MediaSessionService.java
index 9d85167..87665e1 100644
--- a/services/core/java/com/android/server/media/MediaSessionService.java
+++ b/services/core/java/com/android/server/media/MediaSessionService.java
@@ -26,6 +26,8 @@
 import android.content.Context;
 import android.content.Intent;
 import android.content.pm.PackageManager;
+import android.media.AudioManager;
+import android.media.IAudioService;
 import android.media.routeprovider.RouteRequest;
 import android.media.session.ISession;
 import android.media.session.ISessionCallback;
@@ -40,6 +42,7 @@
 import android.os.PowerManager;
 import android.os.RemoteException;
 import android.os.ResultReceiver;
+import android.os.ServiceManager;
 import android.os.UserHandle;
 import android.provider.Settings;
 import android.speech.RecognizerIntent;
@@ -79,6 +82,7 @@
     private final PowerManager.WakeLock mMediaEventWakeLock;
 
     private KeyguardManager mKeyguardManager;
+    private IAudioService mAudioService;
 
     private MediaSessionRecord mPrioritySession;
     private int mCurrentUserId = -1;
@@ -105,6 +109,12 @@
         updateUser();
         mKeyguardManager =
                 (KeyguardManager) getContext().getSystemService(Context.KEYGUARD_SERVICE);
+        mAudioService = getAudioService();
+    }
+
+    private IAudioService getAudioService() {
+        IBinder b = ServiceManager.getService(Context.AUDIO_SERVICE);
+        return IAudioService.Stub.asInterface(b);
     }
 
     /**
@@ -703,6 +713,23 @@
         }
 
         @Override
+        public void dispatchAdjustVolumeBy(int suggestedStream, int delta, int flags)
+                throws RemoteException {
+            final int pid = Binder.getCallingPid();
+            final int uid = Binder.getCallingUid();
+            final long token = Binder.clearCallingIdentity();
+            try {
+                synchronized (mLock) {
+                    MediaSessionRecord session = mPriorityStack
+                            .getDefaultVolumeSession(mCurrentUserId);
+                    dispatchAdjustVolumeByLocked(suggestedStream, delta, flags, session);
+                }
+            } finally {
+                Binder.restoreCallingIdentity(token);
+            }
+        }
+
+        @Override
         public void dump(FileDescriptor fd, final PrintWriter pw, String[] args) {
             if (getContext().checkCallingOrSelfPermission(Manifest.permission.DUMP)
                     != PackageManager.PERMISSION_GRANTED) {
@@ -737,6 +764,49 @@
             }
         }
 
+        private void dispatchAdjustVolumeByLocked(int suggestedStream, int delta, int flags,
+                MediaSessionRecord session) {
+            int direction = 0;
+            int steps = delta;
+            if (delta > 0) {
+                direction = 1;
+            } else if (delta < 0) {
+                direction = -1;
+                steps = -delta;
+            }
+            if (DEBUG) {
+                String sessionInfo = session == null ? null : session.getSessionInfo().toString();
+                Log.d(TAG, "Adjusting session " + sessionInfo + " by " + delta + ". flags=" + flags
+                        + ", suggestedStream=" + suggestedStream);
+
+            }
+            if (session == null) {
+                for (int i = 0; i < steps; i++) {
+                    try {
+                        mAudioService.adjustSuggestedStreamVolume(direction, suggestedStream,
+                                flags, getContext().getOpPackageName());
+                    } catch (RemoteException e) {
+                        Log.e(TAG, "Error adjusting default volume.", e);
+                    }
+                }
+            } else {
+                if (session.getPlaybackType() == MediaSession.VOLUME_TYPE_LOCAL) {
+                    for (int i = 0; i < steps; i++) {
+                        try {
+                            mAudioService.adjustSuggestedStreamVolume(direction,
+                                    session.getAudioStream(), flags,
+                                    getContext().getOpPackageName());
+                        } catch (RemoteException e) {
+                            Log.e(TAG, "Error adjusting volume for stream "
+                                    + session.getAudioStream(), e);
+                        }
+                    }
+                } else if (session.getPlaybackType() == MediaSession.VOLUME_TYPE_REMOTE) {
+                    session.adjustVolumeBy(delta);
+                }
+            }
+        }
+
         private void handleVoiceKeyEventLocked(KeyEvent keyEvent, boolean needWakeLock,
                 MediaSessionRecord session) {
             if (session != null && session.hasFlag(MediaSession.FLAG_EXCLUSIVE_GLOBAL_PRIORITY)) {