Rollback of https://github.com/google/ExoPlayer/commit/dd7223df10e1e72d65a628404a4e851dad44148e

*** Original commit ***

Refactor HlsSampleStreamWrapper#track() to clarify the return paths

I found the original implementation quite hard to follow, and I believe this is functionally identical.

***

PiperOrigin-RevId: 270263186

library/hls/src/main/java/com/google/android/exoplayer2/source/hls/HlsSampleStreamWrapper.java

@@ -127,7 +127,7 @@ import java.util.Set;
   private Format downstreamTrackFormat;
   private boolean released;
 
-  // Tracks are complicated in HLS. See documentation of buildTracksFromSampleStreams for details.
+  // Tracks are complicated in HLS. See documentation of buildTracks for details.
   // Indexed by track (as exposed by this source).
   private TrackGroupArray trackGroups;
   private Set<TrackGroup> optionalTrackGroups;
@@ -815,15 +815,42 @@ import java.util.Set;
     int trackCount = sampleQueues.length;
 
     // Audio and video tracks are handled manually to ignore ids.
-    @Nullable TrackOutput mappedTrack = maybeMapAndGetSampleQueue(id, type);
-    if (mappedTrack != null) {
-      return mappedTrack;
-    }
-    if (tracksEnded) {
-      return createDummyTrackOutput(id, type);
+    if (type == C.TRACK_TYPE_AUDIO) {
+      if (audioSampleQueueIndex != C.INDEX_UNSET) {
+        if (audioSampleQueueMappingDone) {
+          return sampleQueueTrackIds[audioSampleQueueIndex] == id
+              ? sampleQueues[audioSampleQueueIndex]
+              : createDummyTrackOutput(id, type);
+        }
+        audioSampleQueueMappingDone = true;
+        sampleQueueTrackIds[audioSampleQueueIndex] = id;
+        return sampleQueues[audioSampleQueueIndex];
+      } else if (tracksEnded) {
+        return createDummyTrackOutput(id, type);
+      }
+    } else if (type == C.TRACK_TYPE_VIDEO) {
+      if (videoSampleQueueIndex != C.INDEX_UNSET) {
+        if (videoSampleQueueMappingDone) {
+          return sampleQueueTrackIds[videoSampleQueueIndex] == id
+              ? sampleQueues[videoSampleQueueIndex]
+              : createDummyTrackOutput(id, type);
+        }
+        videoSampleQueueMappingDone = true;
+        sampleQueueTrackIds[videoSampleQueueIndex] = id;
+        return sampleQueues[videoSampleQueueIndex];
+      } else if (tracksEnded) {
+        return createDummyTrackOutput(id, type);
+      }
+    } else /* sparse track */ {
+      for (int i = 0; i < trackCount; i++) {
+        if (sampleQueueTrackIds[i] == id) {
+          return sampleQueues[i];
+        }
+      }
+      if (tracksEnded) {
+        return createDummyTrackOutput(id, type);
+      }
     }
-
-    // The relevant SampleQueue hasn't been constructed yet - so construct it:
     SampleQueue trackOutput = new FormatAdjustingSampleQueue(allocator, overridingDrmInitData);
     trackOutput.setSampleOffsetUs(sampleOffsetUs);
     trackOutput.sourceId(chunkUid);
@@ -854,31 +881,6 @@ import java.util.Set;
     return trackOutput;
   }
 
-  @Nullable
-  private TrackOutput maybeMapAndGetSampleQueue(int id, int type) {
-    int sampleQueueIndex;
-    boolean sampleQueueMappingDone;
-    if (type == C.TRACK_TYPE_AUDIO && audioSampleQueueIndex != C.INDEX_UNSET) {
-      sampleQueueIndex = audioSampleQueueIndex;
-      sampleQueueMappingDone = audioSampleQueueMappingDone;
-      audioSampleQueueMappingDone = true;
-    } else if (type == C.TRACK_TYPE_VIDEO && videoSampleQueueIndex != C.INDEX_UNSET) {
-      sampleQueueIndex = videoSampleQueueIndex;
-      sampleQueueMappingDone = videoSampleQueueMappingDone;
-      videoSampleQueueMappingDone = true;
-    } else {
-      return null;
-    }
-
-    if (sampleQueueMappingDone) {
-      return sampleQueueTrackIds[sampleQueueIndex] == id
-          ? sampleQueues[sampleQueueIndex]
-          : createDummyTrackOutput(id, type);
-    } else {
-      return sampleQueues[sampleQueueIndex];
-    }
-  }
-
   @Override
   public void endTracks() {
     tracksEnded = true;