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, 20 insertions, 1 deletions

diff --git a/include/media/AudioIoDescriptor.h b/include/media/AudioIoDescriptor.h
index 2437901..c94b738 100644
--- a/include/media/AudioIoDescriptor.h
+++ b/include/media/AudioIoDescriptor.h
@@ -33,12 +33,31 @@ enum audio_io_config_event {
 class AudioIoDescriptor : public RefBase {
 public:
     AudioIoDescriptor() :
+        mIoHandle(AUDIO_IO_HANDLE_NONE),
         mSamplingRate(0), mFormat(AUDIO_FORMAT_DEFAULT), mChannelMask(AUDIO_CHANNEL_NONE),
-        mFrameCount(0), mLatency(0) {}
+        mFrameCount(0), mLatency(0)
+    {
+        memset(&mPatch, 0, sizeof(struct audio_patch));
+    }
 
     virtual ~AudioIoDescriptor() {}
 
+    audio_port_handle_t getDeviceId() {
+        if (mPatch.num_sources != 0 && mPatch.num_sinks != 0) {
+            if (mPatch.sources[0].type == AUDIO_PORT_TYPE_MIX) {
+                // this is an output mix
+                // FIXME: the API only returns the first device in case of multiple device selection
+                return mPatch.sinks[0].id;
+            } else {
+                // this is an input mix
+                return mPatch.sources[0].id;
+            }
+        }
+        return AUDIO_PORT_HANDLE_NONE;
+    }
+
     audio_io_handle_t mIoHandle;
+    struct audio_patch mPatch;
     uint32_t mSamplingRate;
     audio_format_t mFormat;
     audio_channel_mask_t mChannelMask;