Implement audio device callback

Add class AudioSystem::AudioDeviceCallback notifying
AudioSystem clients upon device selection change on a given
input or output thread.
Maintain a list of installed callback per I/O handle in AudioSystem
and call registered callbacks when an OPEN of CONFIG_CHANGED event
is received on IAudioFlingerClient::ioConfigChanged().
Add methods to AudioTrack and AudioRecord to add and remove device
change callbacks.
Add methods to AudioTrack and AudioRecord to query currently selected
device.
ioConfigChanged() events now convey the audio patch describing
the input or output thread routing.

Fix AudioRecord failure to start when invalidation is
handled by start().

Change-Id: I9e938adf025fa712337c63b1e02a8c18f2a20d39

1 files changed, 34 insertions, 1 deletions

diff --git a/include/media/AudioTrack.h b/include/media/AudioTrack.h
index 0ccd19e..458f4b4 100644
--- a/include/media/AudioTrack.h
+++ b/include/media/AudioTrack.h
@@ -510,7 +510,7 @@ public:
      */
             status_t    setOutputDevice(audio_port_handle_t deviceId);
 
-    /* Returns the ID of the audio device used for output of this AudioTrack.
+    /* Returns the ID of the audio device selected for this AudioTrack.
      * A value of AUDIO_PORT_HANDLE_NONE indicates default (AudioPolicyManager) routing.
      *
      * Parameters:
@@ -518,6 +518,15 @@ public:
      */
      audio_port_handle_t getOutputDevice();
 
+     /* Returns the ID of the audio device actually used by the output to which this AudioTrack is
+      * attached.
+      * A value of AUDIO_PORT_HANDLE_NONE indicates the audio track is not attached to any output.
+      *
+      * Parameters:
+      *  none.
+      */
+     audio_port_handle_t getRoutedDeviceId();
+
     /* Returns the unique session ID associated with this track.
      *
      * Parameters:
@@ -664,6 +673,28 @@ public:
      */
             status_t    getTimestamp(AudioTimestamp& timestamp);
 
+    /* Add an AudioDeviceCallback. The caller will be notified when the audio device to which this
+     * AudioTrack is routed is updated.
+     * Replaces any previously installed callback.
+     * Parameters:
+     *  callback:  The callback interface
+     * Returns NO_ERROR if successful.
+     *         INVALID_OPERATION if the same callback is already installed.
+     *         NO_INIT or PREMISSION_DENIED if AudioFlinger service is not reachable
+     *         BAD_VALUE if the callback is NULL
+     */
+            status_t addAudioDeviceCallback(const sp<AudioSystem::AudioDeviceCallback>& callback);
+
+    /* remove an AudioDeviceCallback.
+     * Parameters:
+     *  callback:  The callback interface
+     * Returns NO_ERROR if successful.
+     *         INVALID_OPERATION if the callback is not installed
+     *         BAD_VALUE if the callback is NULL
+     */
+            status_t removeAudioDeviceCallback(
+                    const sp<AudioSystem::AudioDeviceCallback>& callback);
+
 protected:
     /* copying audio tracks is not allowed */
                         AudioTrack(const AudioTrack& other);
@@ -885,6 +916,8 @@ private:
     uint32_t                mSequence;              // incremented for each new IAudioTrack attempt
     int                     mClientUid;
     pid_t                   mClientPid;
+
+    sp<AudioSystem::AudioDeviceCallback> mDeviceCallback;
 };
 
 class TimedAudioTrack : public AudioTrack