Call AudioMixer only from MixerThread threadLoop.

As part of change:
Remove track name offset by TRACK0.
Move track name management to the Tracks class.
Sync mixer track name to FastMixer track index.

Fixes regression introduced by commit 8ed196a.

Test: SoundPool, AudioTrack CTS, Usability
Bug: 72937362
Bug: 73004420
Change-Id: I2f1a33f6f0da66bcd7aa91e2a4b663ff822df645
diff --git a/services/audioflinger/FastMixer.cpp b/services/audioflinger/FastMixer.cpp
index ace586c..ef466a2 100644
--- a/services/audioflinger/FastMixer.cpp
+++ b/services/audioflinger/FastMixer.cpp
@@ -79,7 +79,6 @@
 
     unsigned i;
     for (i = 0; i < FastMixerState::sMaxFastTracks; ++i) {
-        mFastTrackNames[i] = -1;
         mGenerations[i] = 0;
     }
 #ifdef FAST_THREAD_STATISTICS
@@ -190,7 +189,7 @@
             // FIXME new may block for unbounded time at internal mutex of the heap
             //       implementation; it would be better to have normal mixer allocate for us
             //       to avoid blocking here and to prevent possible priority inversion
-            mMixer = new AudioMixer(frameCount, mSampleRate, FastMixerState::sMaxFastTracks);
+            mMixer = new AudioMixer(frameCount, mSampleRate);
             // FIXME See the other FIXME at FastMixer::setNBLogWriter()
             const size_t mixerFrameSize = mSinkChannelCount
                     * audio_bytes_per_sample(mMixerBufferFormat);
@@ -235,7 +234,6 @@
     dumpState->mTrackMask = currentTrackMask;
     if (current->mFastTracksGen != mFastTracksGen) {
         ALOG_ASSERT(mMixerBuffer != NULL);
-        int name;
 
         // process removed tracks first to avoid running out of track names
         unsigned removedTracks = previousTrackMask & ~currentTrackMask;
@@ -245,9 +243,7 @@
             const FastTrack* fastTrack = &current->mFastTracks[i];
             ALOG_ASSERT(fastTrack->mBufferProvider == NULL);
             if (mMixer != NULL) {
-                name = mFastTrackNames[i];
-                ALOG_ASSERT(name >= 0);
-                mMixer->deleteTrackName(name);
+                mMixer->destroy(i);
             }
 #if !LOG_NDEBUG
             mFastTrackNames[i] = -1;
@@ -265,10 +261,16 @@
             AudioBufferProvider *bufferProvider = fastTrack->mBufferProvider;
             ALOG_ASSERT(bufferProvider != NULL && mFastTrackNames[i] == -1);
             if (mMixer != NULL) {
-                name = mMixer->getTrackName(fastTrack->mChannelMask,
+                const int name = i; // for clarity, choose name as fast track index.
+                status_t status = mMixer->create(
+                        name,
+                        fastTrack->mChannelMask,
                         fastTrack->mFormat, AUDIO_SESSION_OUTPUT_MIX);
-                ALOG_ASSERT(name >= 0);
-                mFastTrackNames[i] = name;
+                LOG_ALWAYS_FATAL_IF(status != NO_ERROR,
+                        "%s: cannot create track name"
+                        " %d, mask %#x, format %#x, sessionId %d in AudioMixer",
+                        __func__, name,
+                        fastTrack->mChannelMask, fastTrack->mFormat, AUDIO_SESSION_OUTPUT_MIX);
                 mMixer->setBufferProvider(name, bufferProvider);
                 mMixer->setParameter(name, AudioMixer::TRACK, AudioMixer::MAIN_BUFFER,
                         (void *)mMixerBuffer);
@@ -300,8 +302,7 @@
                 AudioBufferProvider *bufferProvider = fastTrack->mBufferProvider;
                 ALOG_ASSERT(bufferProvider != NULL);
                 if (mMixer != NULL) {
-                    name = mFastTrackNames[i];
-                    ALOG_ASSERT(name >= 0);
+                    const int name = i;
                     mMixer->setBufferProvider(name, bufferProvider);
                     if (fastTrack->mVolumeProvider == NULL) {
                         float f = AudioMixer::UNITY_GAIN_FLOAT;
@@ -378,8 +379,7 @@
             perTrackTimestamp.mPosition[ExtendedTimestamp::LOCATION_SERVER] = trackFramesWritten;
             fastTrack->mBufferProvider->onTimestamp(perTrackTimestamp);
 
-            int name = mFastTrackNames[i];
-            ALOG_ASSERT(name >= 0);
+            const int name = i;
             if (fastTrack->mVolumeProvider != NULL) {
                 gain_minifloat_packed_t vlr = fastTrack->mVolumeProvider->getVolumeLR();
                 float vlf = float_from_gain(gain_minifloat_unpack_left(vlr));