Fix bug 4064086 Use a death handler on audio focus changes from mode

Use a death handler when audio focus changes are caused by audio
 mode changes.

The bug comes from the fact that audio focus clients that use the
 audio mode for automatic focus handling didn't register a death
 handler, which was set to null. When such a client died, this
 handler was compared against the one to remove from the
 audio focus stack, which resulted in an NPE.
The fix consists in registering a valid IBinder object in the
 audio focus stack, even for clients whose focus requests originate
 from a change in audio mode, as implemented in the
 handleFocusForCalls() method.

Change-Id: Id9e1d3d10afcd99969285f6d60fc4d7dde1e4a10

1 files changed, 17 insertions, 21 deletions

diff --git a/media/java/android/media/AudioService.java b/media/java/android/media/AudioService.java
index 5a73d2d..fd12e19 100644
--- a/media/java/android/media/AudioService.java
+++ b/media/java/android/media/AudioService.java
@@ -805,7 +805,7 @@ public class AudioService extends IAudioService.Stub {
             if (mode != mMode) {
 
                 // automatically handle audio focus for mode changes
-                handleFocusForCalls(mMode, mode);
+                handleFocusForCalls(mMode, mode, cb);
 
                 if (AudioSystem.setPhoneState(mode) == AudioSystem.AUDIO_STATUS_OK) {
                     mMode = mode;
@@ -864,7 +864,7 @@ public class AudioService extends IAudioService.Stub {
     }
 
     /** pre-condition: oldMode != newMode */
-    private void handleFocusForCalls(int oldMode, int newMode) {
+    private void handleFocusForCalls(int oldMode, int newMode, IBinder cb) {
         // if ringing
         if (newMode == AudioSystem.MODE_RINGTONE) {
             // if not ringing silently
@@ -872,8 +872,8 @@ public class AudioService extends IAudioService.Stub {
             if (ringVolume > 0) {
                 // request audio focus for the communication focus entry
                 requestAudioFocus(AudioManager.STREAM_RING,
-                        AudioManager.AUDIOFOCUS_GAIN_TRANSIENT,
-                        null, null /* both allowed to be null only for this clientId */,
+                        AudioManager.AUDIOFOCUS_GAIN_TRANSIENT, cb,
+                        null /* IAudioFocusDispatcher allowed to be null only for this clientId */,
                         IN_VOICE_COMM_FOCUS_ID /*clientId*/);
 
             }
@@ -884,8 +884,8 @@ public class AudioService extends IAudioService.Stub {
             // request audio focus for the communication focus entry
             // (it's ok if focus was already requested during ringing)
             requestAudioFocus(AudioManager.STREAM_RING,
-                    AudioManager.AUDIOFOCUS_GAIN_TRANSIENT,
-                    null, null /* both allowed to be null only for this clientId */,
+                    AudioManager.AUDIOFOCUS_GAIN_TRANSIENT, cb,
+                    null /* IAudioFocusDispatcher allowed to be null only for this clientId */,
                     IN_VOICE_COMM_FOCUS_ID /*clientId*/);
         }
         // if exiting call
@@ -2547,10 +2547,9 @@ public class AudioService extends IAudioService.Stub {
         // the main stream type for the audio focus request is currently not used. It may
         // potentially be used to handle multiple stream type-dependent audio focuses.
 
-        // we need a valid binder callback for clients other than the AudioService's phone
-        // state listener
-        if (!IN_VOICE_COMM_FOCUS_ID.equals(clientId) && ((cb == null) || !cb.pingBinder())) {
-            Log.i(TAG, " AudioFocus  DOA client for requestAudioFocus(), exiting");
+        // we need a valid binder callback for clients
+        if (!cb.pingBinder()) {
+            Log.e(TAG, " AudioFocus DOA client for requestAudioFocus(), aborting.");
             return AudioManager.AUDIOFOCUS_REQUEST_FAILED;
         }
 
@@ -2591,17 +2590,14 @@ public class AudioService extends IAudioService.Stub {
         }//synchronized(mAudioFocusLock)
 
         // handle the potential premature death of the new holder of the focus
-        // (premature death == death before abandoning focus) for a client which is not the
-        // AudioService's phone state listener
-        if (!IN_VOICE_COMM_FOCUS_ID.equals(clientId)) {
-            // Register for client death notification
-            AudioFocusDeathHandler afdh = new AudioFocusDeathHandler(cb);
-            try {
-                cb.linkToDeath(afdh, 0);
-            } catch (RemoteException e) {
-                // client has already died!
-                Log.w(TAG, "AudioFocus  requestAudioFocus() could not link to "+cb+" binder death");
-            }
+        // (premature death == death before abandoning focus)
+        // Register for client death notification
+        AudioFocusDeathHandler afdh = new AudioFocusDeathHandler(cb);
+        try {
+            cb.linkToDeath(afdh, 0);
+        } catch (RemoteException e) {
+            // client has already died!
+            Log.w(TAG, "AudioFocus  requestAudioFocus() could not link to "+cb+" binder death");
         }
 
         return AudioManager.AUDIOFOCUS_REQUEST_GRANTED;