audiopolicy: Add notification when default effects are updated

 * In M, we now have the ability to define a default set of audio effect
   on a per-stream basis. This allows us to get around the problem of
   apps not sending the control intents so we can implement smart
   global effects for specific media types.
 * We still need a session id in order to get a handle and configure them
   from an app like AudioFX, so we'll need to add some plumbing in
   order to send an event to interested applications.
 * This patch implements the native side of this. The Java layer will
   call down thru AudioSystem and register a callback which will be
   invoked by the audio policy when default effects are updated on
   a stream. This callback will receive both the stream type as well
   as the session id.
 * Attaching this listener requires that the caller hold the
   MODIFY_AUDIO_ROUTING permission.

Change-Id: I142b15f2585ffca6a953c3e828e2a7c07b24f56c

1 files changed, 31 insertions, 1 deletions

diff --git a/media/libmedia/AudioSystem.cpp b/media/libmedia/AudioSystem.cpp
index 9d645f0..10ec495 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;
-
+effect_session_callback AudioSystem::gEffectSessionCallback = NULL;
 
 // establish binder interface to AudioFlinger service
 const sp<IAudioFlinger> AudioSystem::get_audio_flinger()
@@ -652,6 +652,21 @@ status_t AudioSystem::AudioFlingerClient::removeAudioDeviceCallback(
     gDynPolicyCallback = cb;
 }
 
+/*static*/ status_t AudioSystem::setEffectSessionCallback(effect_session_callback cb)
+{
+    const sp<IAudioPolicyService>& aps = AudioSystem::get_audio_policy_service();
+    if (aps == 0) return PERMISSION_DENIED;
+
+    Mutex::Autolock _l(gLock);
+    gEffectSessionCallback = cb;
+
+    status_t status = aps->setEffectSessionCallbacksEnabled(cb != NULL);
+    if (status != OK) {
+        gEffectSessionCallback = NULL;
+    }
+    return status;
+}
+
 // client singleton for AudioPolicyService binder interface
 // protected by gLockAPS
 sp<IAudioPolicyService> AudioSystem::gAudioPolicyService;
@@ -1223,6 +1238,21 @@ void AudioSystem::AudioPolicyServiceClient::onDynamicPolicyMixStateUpdate(
     }
 }
 
+void AudioSystem::AudioPolicyServiceClient::onOutputSessionEffectsUpdate(
+        audio_stream_type_t stream, audio_unique_id_t sessionId, bool added)
+{
+    ALOGV("AudioPolicyServiceClient::onOutputSessionEffectsUpdate(%d, %d, %d)", stream, sessionId, added);
+    effect_session_callback cb = NULL;
+    {
+        Mutex::Autolock _l(AudioSystem::gLock);
+        cb = gEffectSessionCallback;
+    }
+
+    if (cb != NULL) {
+        cb(AUDIO_OUTPUT_SESSION_EFFECTS_UPDATE, stream, sessionId, added);
+    }
+}
+
 void AudioSystem::AudioPolicyServiceClient::binderDied(const wp<IBinder>& who __unused)
 {
     {