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

3 files changed, 72 insertions, 2 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)
 {
     {
diff --git a/media/libmedia/IAudioPolicyService.cpp b/media/libmedia/IAudioPolicyService.cpp
index 76b5924..6ff8149 100644
--- a/media/libmedia/IAudioPolicyService.cpp
+++ b/media/libmedia/IAudioPolicyService.cpp
@@ -74,6 +74,7 @@ enum {
     START_AUDIO_SOURCE,
     STOP_AUDIO_SOURCE,
     SET_AUDIO_PORT_CALLBACK_ENABLED,
+    SET_EFFECT_SESSION_CALLBACK_ENABLED,
 };
 
 #define MAX_ITEMS_PER_LIST 1024
@@ -655,6 +656,18 @@ public:
         remote()->transact(SET_AUDIO_PORT_CALLBACK_ENABLED, data, &reply);
     }
 
+    virtual status_t setEffectSessionCallbacksEnabled(bool enabled)
+    {
+        Parcel data, reply;
+        data.writeInterfaceToken(IAudioPolicyService::getInterfaceDescriptor());
+        data.writeInt32(enabled ? 1 : 0);
+        status_t status = remote()->transact(SET_EFFECT_SESSION_CALLBACK_ENABLED, data, &reply);
+        if (status != NO_ERROR) {
+            return status;
+        }
+        return (status_t)reply.readInt32();
+    }
+
     virtual status_t acquireSoundTriggerSession(audio_session_t *session,
                                             audio_io_handle_t *ioHandle,
                                             audio_devices_t *device)
@@ -1238,6 +1251,13 @@ status_t BnAudioPolicyService::onTransact(
             return NO_ERROR;
         } break;
 
+        case SET_EFFECT_SESSION_CALLBACK_ENABLED: {
+            CHECK_INTERFACE(IAudioPolicyService, data, reply);
+            status_t status = setEffectSessionCallbacksEnabled(data.readInt32() == 1);
+            reply->writeInt32(status);
+            return NO_ERROR;
+        } break;
+
         case ACQUIRE_SOUNDTRIGGER_SESSION: {
             CHECK_INTERFACE(IAudioPolicyService, data, reply);
             sp<IAudioPolicyServiceClient> client = interface_cast<IAudioPolicyServiceClient>(
diff --git a/media/libmedia/IAudioPolicyServiceClient.cpp b/media/libmedia/IAudioPolicyServiceClient.cpp
index 65cc7d6..d6207ce 100644
--- a/media/libmedia/IAudioPolicyServiceClient.cpp
+++ b/media/libmedia/IAudioPolicyServiceClient.cpp
@@ -30,7 +30,8 @@ namespace android {
 enum {
     PORT_LIST_UPDATE = IBinder::FIRST_CALL_TRANSACTION,
     PATCH_LIST_UPDATE,
-    MIX_STATE_UPDATE
+    MIX_STATE_UPDATE,
+    OUTPUT_SESSION_EFFECTS_UPDATE
 };
 
 class BpAudioPolicyServiceClient : public BpInterface<IAudioPolicyServiceClient>
@@ -63,6 +64,17 @@ public:
         data.writeInt32(state);
         remote()->transact(MIX_STATE_UPDATE, data, &reply, IBinder::FLAG_ONEWAY);
     }
+
+    void onOutputSessionEffectsUpdate(audio_stream_type_t stream,
+                                      audio_unique_id_t sessionId, bool added)
+    {
+        Parcel data, reply;
+        data.writeInterfaceToken(IAudioPolicyServiceClient::getInterfaceDescriptor());
+        data.writeInt32(stream);
+        data.writeInt32(sessionId);
+        data.writeInt32(added ? 1 : 0);
+        remote()->transact(OUTPUT_SESSION_EFFECTS_UPDATE, data, &reply, IBinder::FLAG_ONEWAY);
+    }
 };
 
 IMPLEMENT_META_INTERFACE(AudioPolicyServiceClient, "android.media.IAudioPolicyServiceClient");
@@ -90,6 +102,14 @@ status_t BnAudioPolicyServiceClient::onTransact(
             onDynamicPolicyMixStateUpdate(regId, state);
             return NO_ERROR;
     }
+    case OUTPUT_SESSION_EFFECTS_UPDATE: {
+            CHECK_INTERFACE(IAudioPolicyServiceClient, data, reply);
+            audio_stream_type_t stream = static_cast<audio_stream_type_t>(data.readInt32());
+            audio_unique_id_t sessionId = static_cast<audio_unique_id_t>(data.readInt32());
+            bool added = data.readInt32() > 0;
+            onOutputSessionEffectsUpdate(stream, sessionId, added);
+            return NO_ERROR;
+    }
     default:
         return BBinder::onTransact(code, data, reply, flags);
     }