Add callback for codec format change.

When creating native audio track, a IAudioTrackCallback will be created
systematically. All callbacks will be cached in Threads and protected by
a lock. Whenever there is a callback event from audio HAL, it will
finally trigger callback to native audio track. Currently, there is only
one callback event, which is codec format change.

Bug: 150301890
Test: manual
Change-Id: I32293627ed923b17dd25f11f0ee0a0c35cd7c01f
diff --git a/services/audioflinger/AudioFlinger.cpp b/services/audioflinger/AudioFlinger.cpp
index e5a6e27..4adbad2 100644
--- a/services/audioflinger/AudioFlinger.cpp
+++ b/services/audioflinger/AudioFlinger.cpp
@@ -833,7 +833,7 @@
                                       input.notificationsPerBuffer, input.speed,
                                       input.sharedBuffer, sessionId, &output.flags,
                                       callingPid, input.clientInfo.clientTid, clientUid,
-                                      &lStatus, portId);
+                                      &lStatus, portId, input.audioTrackCallback);
         LOG_ALWAYS_FATAL_IF((lStatus == NO_ERROR) && (track == 0));
         // we don't abort yet if lStatus != NO_ERROR; there is still work to be done regardless
 
diff --git a/services/audioflinger/AudioFlinger.h b/services/audioflinger/AudioFlinger.h
index a16fa94..d69b49d 100644
--- a/services/audioflinger/AudioFlinger.h
+++ b/services/audioflinger/AudioFlinger.h
@@ -33,6 +33,7 @@
 #include <sys/types.h>
 #include <limits.h>
 
+#include <android/media/IAudioTrackCallback.h>
 #include <android/os/BnExternalVibrationController.h>
 #include <android-base/macros.h>
 
diff --git a/services/audioflinger/Threads.cpp b/services/audioflinger/Threads.cpp
index 2833525..f24dcd7 100644
--- a/services/audioflinger/Threads.cpp
+++ b/services/audioflinger/Threads.cpp
@@ -42,6 +42,7 @@
 #include <private/media/AudioTrackShared.h>
 #include <private/android_filesystem_config.h>
 #include <audio_utils/Balance.h>
+#include <audio_utils/Metadata.h>
 #include <audio_utils/channels.h>
 #include <audio_utils/mono_blend.h>
 #include <audio_utils/primitives.h>
@@ -1921,6 +1922,16 @@
 
 void AudioFlinger::PlaybackThread::onFirstRef()
 {
+    if (mOutput == nullptr || mOutput->stream == nullptr) {
+        ALOGE("The stream is not open yet"); // This should not happen.
+    } else {
+        // setEventCallback will need a strong pointer as a parameter. Calling it
+        // here instead of constructor of PlaybackThread so that the onFirstRef
+        // callback would not be made on an incompletely constructed object.
+        if (mOutput->stream->setEventCallback(this) != OK) {
+            ALOGE("Failed to add event callback");
+        }
+    }
     run(mThreadName, ANDROID_PRIORITY_URGENT_AUDIO);
 }
 
@@ -2050,7 +2061,8 @@
         pid_t tid,
         uid_t uid,
         status_t *status,
-        audio_port_handle_t portId)
+        audio_port_handle_t portId,
+        const sp<media::IAudioTrackCallback>& callback)
 {
     size_t frameCount = *pFrameCount;
     size_t notificationFrameCount = *pNotificationFrameCount;
@@ -2340,6 +2352,12 @@
             goto Exit;
         }
         mTracks.add(track);
+        {
+            Mutex::Autolock _atCbL(mAudioTrackCbLock);
+            if (callback.get() != nullptr) {
+                mAudioTrackCallbacks.emplace(callback);
+            }
+        }
 
         sp<EffectChain> chain = getEffectChain_l(sessionId);
         if (chain != 0) {
@@ -2642,6 +2660,29 @@
     mCallbackThread->setAsyncError();
 }
 
+void AudioFlinger::PlaybackThread::onCodecFormatChanged(
+        const std::basic_string<uint8_t>& metadataBs)
+{
+    std::thread([this, metadataBs]() {
+            audio_utils::metadata::Data metadata =
+                    audio_utils::metadata::dataFromByteString(metadataBs);
+            if (metadata.empty()) {
+                ALOGW("Can not transform the buffer to audio metadata, %s, %d",
+                      reinterpret_cast<char*>(const_cast<uint8_t*>(metadataBs.data())),
+                      (int)metadataBs.size());
+                return;
+            }
+
+            audio_utils::metadata::ByteString metaDataStr =
+                    audio_utils::metadata::byteStringFromData(metadata);
+            std::vector metadataVec(metaDataStr.begin(), metaDataStr.end());
+            Mutex::Autolock _l(mAudioTrackCbLock);
+            for (const auto& callback : mAudioTrackCallbacks) {
+                callback->onCodecFormatChanged(metadataVec);
+            }
+    }).detach();
+}
+
 void AudioFlinger::PlaybackThread::resetWriteBlocked(uint32_t sequence)
 {
     Mutex::Autolock _l(mLock);
diff --git a/services/audioflinger/Threads.h b/services/audioflinger/Threads.h
index b0eb75d..153cf7c 100644
--- a/services/audioflinger/Threads.h
+++ b/services/audioflinger/Threads.h
@@ -720,7 +720,7 @@
 
 // --- PlaybackThread ---
 class PlaybackThread : public ThreadBase, public StreamOutHalInterfaceCallback,
-    public VolumeInterface {
+                       public VolumeInterface, public StreamOutHalInterfaceEventCallback {
 public:
 
 #include "PlaybackTracks.h"
@@ -796,6 +796,10 @@
     virtual     void        onAddNewTrack_l();
                 void        onAsyncError(); // error reported by AsyncCallbackThread
 
+    // StreamHalInterfaceCodecFormatCallback implementation
+                void        onCodecFormatChanged(
+                                const std::basic_string<uint8_t>& metadataBs) override;
+
     // ThreadBase virtuals
     virtual     void        preExit();
 
@@ -845,7 +849,8 @@
                                 pid_t tid,
                                 uid_t uid,
                                 status_t *status /*non-NULL*/,
-                                audio_port_handle_t portId);
+                                audio_port_handle_t portId,
+                                const sp<media::IAudioTrackCallback>& callback);
 
                 AudioStreamOut* getOutput() const;
                 AudioStreamOut* clearOutput();
@@ -1168,6 +1173,10 @@
     uint32_t                        mDrainSequence;
     sp<AsyncCallbackThread>         mCallbackThread;
 
+    Mutex                                    mAudioTrackCbLock;
+    // Record of IAudioTrackCallback
+    std::set<sp<media::IAudioTrackCallback>> mAudioTrackCallbacks;
+
 private:
     // The HAL output sink is treated as non-blocking, but current implementation is blocking
     sp<NBAIO_Sink>          mOutputSink;