aaudio: refactor references to shared FIFO

Reduce passing of raw pointers.
Use shared_ptrs and unique_ptrs.
Simplify memory management.

Refactor FifoBuffer into two subclasses so that
the internal memory management is simpler.

Bug: 151650670
Test: OboeTester "TEST OUTPUT"
Test: disable EXCLUSIVE mode
Test: OboeTester "ECHO INPUT TO OUTPUT"
Test: disable INPUT EXCLUSIVE mode
Change-Id: I10981767f8719f3cc3525df211285c53219a7979
diff --git a/services/oboeservice/AAudioServiceStreamBase.cpp b/services/oboeservice/AAudioServiceStreamBase.cpp
index 663dae2..ea691cf 100644
--- a/services/oboeservice/AAudioServiceStreamBase.cpp
+++ b/services/oboeservice/AAudioServiceStreamBase.cpp
@@ -46,8 +46,7 @@
  */
 
 AAudioServiceStreamBase::AAudioServiceStreamBase(AAudioService &audioService)
-        : mUpMessageQueue(nullptr)
-        , mTimestampThread("AATime")
+        : mTimestampThread("AATime")
         , mAtomicStreamTimestamp()
         , mAudioService(audioService) {
     mMmapClient.clientUid = -1;
@@ -56,6 +55,8 @@
 }
 
 AAudioServiceStreamBase::~AAudioServiceStreamBase() {
+    ALOGD("%s() called", __func__);
+
     // May not be set if open failed.
     if (mMetricsId.size() > 0) {
         mediametrics::LogItem(mMetricsId)
@@ -140,7 +141,7 @@
             return AAUDIO_ERROR_INVALID_STATE;
         }
 
-        mUpMessageQueue = new SharedRingBuffer();
+        mUpMessageQueue = std::make_shared<SharedRingBuffer>();
         result = mUpMessageQueue->allocate(sizeof(AAudioServiceMessage),
                                            QUEUE_UP_CAPACITY_COMMANDS);
         if (result != AAUDIO_OK) {
@@ -179,6 +180,8 @@
         return AAUDIO_OK;
     }
 
+    // This will call stopTimestampThread() and also stop the stream,
+    // just in case it was not already stopped.
     stop_l();
 
     aaudio_result_t result = AAUDIO_OK;
@@ -194,13 +197,6 @@
         mServiceEndpoint.clear(); // endpoint will hold the pointer after this method returns.
     }
 
-    {
-        std::lock_guard<std::mutex> lock(mUpMessageQueueLock);
-        stopTimestampThread();
-        delete mUpMessageQueue;
-        mUpMessageQueue = nullptr;
-    }
-
     setState(AAUDIO_STREAM_STATE_CLOSED);
 
     mediametrics::LogItem(mMetricsId)
@@ -514,12 +510,8 @@
         ALOGE("%s(): mUpMessageQueue null! - stream not open", __func__);
         return true;
     }
-    int32_t framesAvailable = mUpMessageQueue->getFifoBuffer()
-        ->getFullFramesAvailable();
-    int32_t capacity = mUpMessageQueue->getFifoBuffer()
-        ->getBufferCapacityInFrames();
     // Is it half full or more
-    return framesAvailable >= (capacity / 2);
+    return mUpMessageQueue->getFractionalFullness() >= 0.5;
 }
 
 aaudio_result_t AAudioServiceStreamBase::writeUpMessageQueue(AAudioServiceMessage *command) {