audiopolicy: Add AudioSessionInfo API

 * This patch introduces a new API which allows applications to
   query the state of the audio effects system, and receive
   callbacks with the necessary information to attach effects
   to any stream.
 * In the future, this may come as part of the AudioPort system,
   but since that's an active area of development by Google, we
   will dodge it for now.
 * The policy now simply keeps a refcounted list of objects which
   hold various bits of stream metadata. Callbacks are sent on
   stream open/close to applications which might be listening
   for them.

Change-Id: I2d554d36e1378f4eb7b276010a3bfe8345c22ecd

1 files changed, 38 insertions, 1 deletions

diff --git a/media/libmedia/AudioSystem.cpp b/media/libmedia/AudioSystem.cpp
index 9d645f0..2e9fca9 100644
--- a/media/libmedia/AudioSystem.cpp
+++ b/media/libmedia/AudioSystem.cpp
@@ -37,7 +37,7 @@ sp<IAudioFlinger> AudioSystem::gAudioFlinger;
 sp<AudioSystem::AudioFlingerClient> AudioSystem::gAudioFlingerClient;
 audio_error_callback AudioSystem::gAudioErrorCallback = NULL;
 dynamic_policy_callback AudioSystem::gDynPolicyCallback = NULL;
-
+audio_session_callback AudioSystem::gAudioSessionCallback = NULL;
 
 // establish binder interface to AudioFlinger service
 const sp<IAudioFlinger> AudioSystem::get_audio_flinger()
@@ -652,6 +652,17 @@ status_t AudioSystem::AudioFlingerClient::removeAudioDeviceCallback(
     gDynPolicyCallback = cb;
 }
 
+/*static*/ status_t AudioSystem::setAudioSessionCallback(audio_session_callback cb)
+{
+    const sp<IAudioPolicyService>& aps = AudioSystem::get_audio_policy_service();
+    if (aps == 0) return PERMISSION_DENIED;
+
+    Mutex::Autolock _l(gLock);
+    gAudioSessionCallback = cb;
+
+    return NO_ERROR;
+}
+
 // client singleton for AudioPolicyService binder interface
 // protected by gLockAPS
 sp<IAudioPolicyService> AudioSystem::gAudioPolicyService;
@@ -1223,6 +1234,32 @@ void AudioSystem::AudioPolicyServiceClient::onDynamicPolicyMixStateUpdate(
     }
 }
 
+// ---------------------------------------------------------------------------
+
+status_t AudioSystem::listAudioSessions(audio_stream_type_t stream,
+                                        Vector< sp<AudioSessionInfo>> &sessions)
+{
+    const sp<IAudioPolicyService>& aps = AudioSystem::get_audio_policy_service();
+    if (aps == 0) return PERMISSION_DENIED;
+    return aps->listAudioSessions(stream, sessions);
+}
+
+void AudioSystem::AudioPolicyServiceClient::onOutputSessionEffectsUpdate(
+        sp<AudioSessionInfo>& info, bool added)
+{
+    ALOGV("AudioPolicyServiceClient::onOutputSessionEffectsUpdate(%d, %d, %d)",
+            info->mStream, info->mSessionId, added);
+    audio_session_callback cb = NULL;
+    {
+        Mutex::Autolock _l(AudioSystem::gLock);
+        cb = gAudioSessionCallback;
+    }
+
+    if (cb != NULL) {
+        cb(AUDIO_OUTPUT_SESSION_EFFECTS_UPDATE, info, added);
+    }
+}
+
 void AudioSystem::AudioPolicyServiceClient::binderDied(const wp<IBinder>& who __unused)
 {
     {