Add IAudioTrack::getTimestamp()

with dummy implementation in AudioFlinger::TrackHandle, and
implement AudioTrack::getTimestamp() using IAudioTrack.

Also document invariant that mAudioTrack and control block are always
non-0 after successful initialization.

Change-Id: I9861d1454cff7decf795d5d5898ac7999a9f3b7e

6 files changed, 49 insertions, 13 deletions

diff --git a/include/media/AudioTrack.h b/include/media/AudioTrack.h
index ebb7ef3..453c106 100644
--- a/include/media/AudioTrack.h
+++ b/include/media/AudioTrack.h
@@ -227,6 +227,7 @@ public:
      *  - INVALID_OPERATION: AudioTrack is already initialized
      *  - BAD_VALUE: invalid parameter (channelMask, format, sampleRate...)
      *  - NO_INIT: audio server or audio hardware not initialized
+     * If status is not equal to NO_ERROR, don't call any other APIs on this AudioTrack.
      * If sharedBuffer is non-0, the frameCount parameter is ignored and
      * replaced by the shared buffer's total allocated size in frame units.
      *
@@ -249,7 +250,7 @@ public:
                             transfer_type transferType = TRANSFER_DEFAULT,
                             const audio_offload_info_t *offloadInfo = NULL);
 
-    /* Result of constructing the AudioTrack. This must be checked
+    /* Result of constructing the AudioTrack. This must be checked for successful initialization
      * before using any AudioTrack API (except for set()), because using
      * an uninitialized AudioTrack produces undefined results.
      * See set() method above for possible return codes.
@@ -646,7 +647,7 @@ protected:
             bool     isOffloaded() const
                 { return (mFlags & AUDIO_OUTPUT_FLAG_COMPRESS_OFFLOAD) != 0; }
 
-    // may be changed if IAudioTrack is re-created
+    // Next 3 fields may be changed if IAudioTrack is re-created, but always != 0
     sp<IAudioTrack>         mAudioTrack;
     sp<IMemory>             mCblkMemory;
     audio_track_cblk_t*     mCblk;                  // re-load after mLock.unlock()
diff --git a/include/media/IAudioTrack.h b/include/media/IAudioTrack.h
index 1014403..afac4ae 100644
--- a/include/media/IAudioTrack.h
+++ b/include/media/IAudioTrack.h
@@ -26,6 +26,7 @@
 #include <binder/IMemory.h>
 #include <utils/LinearTransform.h>
 #include <utils/String8.h>
+#include <media/AudioTimestamp.h>
 
 namespace android {
 
@@ -86,6 +87,9 @@ public:
 
     /* Send parameters to the audio hardware */
     virtual status_t    setParameters(const String8& keyValuePairs) = 0;
+
+    /* Return NO_ERROR if timestamp is valid */
+    virtual status_t    getTimestamp(AudioTimestamp& timestamp) = 0;
 };
 
 // ----------------------------------------------------------------------------
diff --git a/media/libmedia/AudioTrack.cpp b/media/libmedia/AudioTrack.cpp
index d90e733..78ae37e 100644
--- a/media/libmedia/AudioTrack.cpp
+++ b/media/libmedia/AudioTrack.cpp
@@ -148,10 +148,8 @@ AudioTrack::~AudioTrack()
             mAudioTrackThread->requestExitAndWait();
             mAudioTrackThread.clear();
         }
-        if (mAudioTrack != 0) {
-            mAudioTrack->asBinder()->unlinkToDeath(mDeathNotifier, this);
-            mAudioTrack.clear();
-        }
+        mAudioTrack->asBinder()->unlinkToDeath(mDeathNotifier, this);
+        mAudioTrack.clear();
         IPCThreadState::self()->flushCommands();
         AudioSystem::releaseAudioSessionId(mSessionId);
     }
@@ -222,6 +220,7 @@ status_t AudioTrack::set(
 
     AutoMutex lock(mLock);
 
+    // invariant that mAudioTrack != 0 is true only after set() returns successfully
     if (mAudioTrack != 0) {
         ALOGE("Track already in use");
         return INVALID_OPERATION;
@@ -965,6 +964,7 @@ status_t AudioTrack::createTrack_l(
         ALOGE("Could not get control block");
         return NO_INIT;
     }
+    // invariant that mAudioTrack != 0 is true only after set() returns successfully
     if (mAudioTrack != 0) {
         mAudioTrack->asBinder()->unlinkToDeath(mDeathNotifier, this);
         mDeathNotifier.clear();
@@ -1705,16 +1705,13 @@ status_t AudioTrack::restoreTrack_l(const char *from)
 status_t AudioTrack::setParameters(const String8& keyValuePairs)
 {
     AutoMutex lock(mLock);
-    if (mAudioTrack != 0) {
-        return mAudioTrack->setParameters(keyValuePairs);
-    } else {
-        return NO_INIT;
-    }
+    return mAudioTrack->setParameters(keyValuePairs);
 }
 
 status_t AudioTrack::getTimestamp(AudioTimestamp& timestamp)
 {
-    return INVALID_OPERATION;
+    AutoMutex lock(mLock);
+    return mAudioTrack->getTimestamp(timestamp);
 }
 
 String8 AudioTrack::getParameters(const String8& keys)
diff --git a/media/libmedia/IAudioTrack.cpp b/media/libmedia/IAudioTrack.cpp
index a2b49a3..f0d75ba 100644
--- a/media/libmedia/IAudioTrack.cpp
+++ b/media/libmedia/IAudioTrack.cpp
@@ -39,7 +39,8 @@ enum {
     ALLOCATE_TIMED_BUFFER,
     QUEUE_TIMED_BUFFER,
     SET_MEDIA_TIME_TRANSFORM,
-    SET_PARAMETERS
+    SET_PARAMETERS,
+    GET_TIMESTAMP,
 };
 
 class BpAudioTrack : public BpInterface<IAudioTrack>
@@ -166,6 +167,21 @@ public:
         }
         return status;
     }
+
+    virtual status_t getTimestamp(AudioTimestamp& timestamp) {
+        Parcel data, reply;
+        data.writeInterfaceToken(IAudioTrack::getInterfaceDescriptor());
+        status_t status = remote()->transact(GET_TIMESTAMP, data, &reply);
+        if (status == NO_ERROR) {
+            status = reply.readInt32();
+            if (status == NO_ERROR) {
+                timestamp.mPosition = reply.readInt32();
+                timestamp.mTime.tv_sec = reply.readInt32();
+                timestamp.mTime.tv_nsec = reply.readInt32();
+            }
+        }
+        return status;
+    }
 };
 
 IMPLEMENT_META_INTERFACE(AudioTrack, "android.media.IAudioTrack");
@@ -241,6 +257,18 @@ status_t BnAudioTrack::onTransact(
             reply->writeInt32(setParameters(keyValuePairs));
             return NO_ERROR;
         } break;
+        case GET_TIMESTAMP: {
+            CHECK_INTERFACE(IAudioTrack, data, reply);
+            AudioTimestamp timestamp;
+            status_t status = getTimestamp(timestamp);
+            reply->writeInt32(status);
+            if (status == NO_ERROR) {
+                reply->writeInt32(timestamp.mPosition);
+                reply->writeInt32(timestamp.mTime.tv_sec);
+                reply->writeInt32(timestamp.mTime.tv_nsec);
+            }
+            return NO_ERROR;
+        } break;
         default:
             return BBinder::onTransact(code, data, reply, flags);
     }
diff --git a/services/audioflinger/AudioFlinger.h b/services/audioflinger/AudioFlinger.h
index e5e4113..5df04f4 100644
--- a/services/audioflinger/AudioFlinger.h
+++ b/services/audioflinger/AudioFlinger.h
@@ -411,6 +411,7 @@ private:
         virtual status_t    setMediaTimeTransform(const LinearTransform& xform,
                                                   int target);
         virtual status_t    setParameters(const String8& keyValuePairs);
+        virtual status_t    getTimestamp(AudioTimestamp& timestamp);
 
         virtual status_t onTransact(
             uint32_t code, const Parcel& data, Parcel* reply, uint32_t flags);
diff --git a/services/audioflinger/Tracks.cpp b/services/audioflinger/Tracks.cpp
index e676365..d1ab3c8 100644
--- a/services/audioflinger/Tracks.cpp
+++ b/services/audioflinger/Tracks.cpp
@@ -283,6 +283,11 @@ status_t AudioFlinger::TrackHandle::setParameters(const String8& keyValuePairs)
     return mTrack->setParameters(keyValuePairs);
 }
 
+status_t AudioFlinger::TrackHandle::getTimestamp(AudioTimestamp& timestamp)
+{
+    return INVALID_OPERATION;
+}
+
 status_t AudioFlinger::TrackHandle::onTransact(
     uint32_t code, const Parcel& data, Parcel* reply, uint32_t flags)
 {