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, 54 insertions, 12 deletions

diff --git a/services/audiopolicy/service/AudioPolicyInterfaceImpl.cpp b/services/audiopolicy/service/AudioPolicyInterfaceImpl.cpp
index c0d3866..f0be341 100644
--- a/services/audiopolicy/service/AudioPolicyInterfaceImpl.cpp
+++ b/services/audiopolicy/service/AudioPolicyInterfaceImpl.cpp
@@ -161,19 +161,32 @@ status_t AudioPolicyService::getOutputForAttr(const audio_attributes_t *attr,
     if (mAudioPolicyManager == NULL) {
         return NO_INIT;
     }
-    ALOGV("getOutput()");
-    Mutex::Autolock _l(mLock);
+    ALOGV("getOutputForAttr()");
+    status_t status = NO_ERROR;
+    sp<AudioPolicyEffects> audioPolicyEffects;
+    {
+        Mutex::Autolock _l(mLock);
 
-    // if the caller is us, trust the specified uid
-    if (IPCThreadState::self()->getCallingPid() != getpid_cached || uid == (uid_t)-1) {
-        uid_t newclientUid = IPCThreadState::self()->getCallingUid();
-        if (uid != (uid_t)-1 && uid != newclientUid) {
-            ALOGW("%s uid %d tried to pass itself off as %d", __FUNCTION__, newclientUid, uid);
+        // if the caller is us, trust the specified uid
+        if (IPCThreadState::self()->getCallingPid() != getpid_cached || uid == (uid_t)-1) {
+            uid_t newclientUid = IPCThreadState::self()->getCallingUid();
+            if (uid != (uid_t)-1 && uid != newclientUid) {
+                ALOGW("%s uid %d tried to pass itself off as %d", __FUNCTION__, newclientUid, uid);
+            }
+            uid = newclientUid;
         }
-        uid = newclientUid;
+        status = mAudioPolicyManager->getOutputForAttr(attr, output, session, stream, uid, samplingRate,
+                                 format, channelMask, flags, selectedDeviceId, offloadInfo);
+
+        audioPolicyEffects = mAudioPolicyEffects;
+    }
+
+    if (status == NO_ERROR && audioPolicyEffects != 0) {
+        audioPolicyEffects->updateOutputAudioSessionInfo(*output,
+                *stream, session, flags, channelMask, uid);
     }
-    return mAudioPolicyManager->getOutputForAttr(attr, output, session, stream, uid, samplingRate,
-                                    format, channelMask, flags, selectedDeviceId, offloadInfo);
+
+    return status;
 }
 
 status_t AudioPolicyService::startOutput(audio_io_handle_t output,
@@ -269,8 +282,16 @@ void AudioPolicyService::doReleaseOutput(audio_io_handle_t output,
                                          audio_session_t session)
 {
     ALOGV("doReleaseOutput from tid %d", gettid());
-    Mutex::Autolock _l(mLock);
-    mAudioPolicyManager->releaseOutput(output, stream, session);
+    sp<AudioPolicyEffects>audioPolicyEffects;
+    {
+        Mutex::Autolock _l(mLock);
+        audioPolicyEffects = mAudioPolicyEffects;
+        mAudioPolicyManager->releaseOutput(output, stream, session);
+    }
+    if (audioPolicyEffects != 0) {
+        audioPolicyEffects->releaseOutputAudioSessionInfo(output,
+                stream, session);
+    }
 }
 
 status_t AudioPolicyService::getInputForAttr(const audio_attributes_t *attr,
@@ -717,4 +738,25 @@ status_t AudioPolicyService::stopAudioSource(audio_io_handle_t handle)
     return mAudioPolicyManager->stopAudioSource(handle);
 }
 
+status_t AudioPolicyService::listAudioSessions(audio_stream_type_t streams,
+                                               Vector< sp<AudioSessionInfo>> &sessions)
+{
+    sp<AudioPolicyEffects> audioPolicyEffects;
+    {
+        Mutex::Autolock _l(mLock);
+        if (mAudioPolicyManager == NULL) {
+            return NO_INIT;
+        }
+        audioPolicyEffects = mAudioPolicyEffects;
+    }
+
+    if (audioPolicyEffects != 0) {
+        return audioPolicyEffects->listAudioSessions(streams, sessions);
+    }
+
+    // no errors here if effects are not available
+    return NO_ERROR;
+}
+
+
 }; // namespace android