Align Chunk/HLS sample sources.

Having moved HLS to use single sample queues per track, these
classes have become relatively similar. This CL aligns the two
to make this more obvious. It remains unclear whether it'll
ever be sensible to merge them; there are still some niggly
complications for HLS.
-------------
Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=120429618

library/src/main/java/com/google/android/exoplayer/chunk/ChunkSampleSource.java

@@ -51,31 +51,31 @@ public class ChunkSampleSource implements SampleSource, TrackStream, Loader.Call
   public static final int DEFAULT_MIN_LOADABLE_RETRY_COUNT = 3;
 
   private final Loader loader;
-  private final LoadControl loadControl;
   private final ChunkSource chunkSource;
-  private final ChunkHolder nextChunkHolder;
   private final LinkedList<BaseMediaChunk> mediaChunks;
   private final List<BaseMediaChunk> readOnlyMediaChunks;
   private final DefaultTrackOutput sampleQueue;
   private final int bufferSizeContribution;
+  private final ChunkHolder nextChunkHolder;
   private final EventDispatcher eventDispatcher;
+  private final LoadControl loadControl;
 
   private boolean prepared;
-  private long downstreamPositionUs;
-  private long lastSeekPositionUs;
-  private long pendingResetPositionUs;
   private long lastPreferredQueueSizeEvaluationTimeMs;
-  private boolean pendingReset;
+  private Format downstreamFormat;
 
   private TrackGroupArray trackGroups;
-  private long durationUs;
-  private boolean loadingFinished;
   private boolean trackEnabled;
-  private long currentLoadStartTimeMs;
+  private boolean pendingReset;
+  private Format downstreamSampleFormat;
+
+  private long downstreamPositionUs;
+  private long lastSeekPositionUs;
+  private long pendingResetPositionUs;
 
   private Chunk currentLoadable;
-  private Format downstreamFormat;
-  private Format downstreamSampleFormat;
+  private long currentLoadStartTimeMs;
+  private boolean loadingFinished;
 
   /**
    * @param chunkSource A {@link ChunkSource} from which chunks to load are obtained.
@@ -139,7 +139,6 @@ public class ChunkSampleSource implements SampleSource, TrackStream, Loader.Call
     if (!chunkSource.prepare()) {
       return false;
     }
-    durationUs = chunkSource.getDurationUs();
     TrackGroup tracks = chunkSource.getTracks();
     if (tracks != null) {
       trackGroups = new TrackGroupArray(tracks);
@@ -152,7 +151,7 @@ public class ChunkSampleSource implements SampleSource, TrackStream, Loader.Call
 
   @Override
   public long getDurationUs() {
-    return durationUs;
+    return chunkSource.getDurationUs();
   }
 
   @Override
@@ -222,9 +221,14 @@ public class ChunkSampleSource implements SampleSource, TrackStream, Loader.Call
     } else if (isPendingReset()) {
       return pendingResetPositionUs;
     } else {
-      long largestQueuedTimestampUs = sampleQueue.getLargestQueuedTimestampUs();
-      return largestQueuedTimestampUs == Long.MIN_VALUE ? downstreamPositionUs
-          : largestQueuedTimestampUs;
+      long bufferedPositionUs = downstreamPositionUs;
+      BaseMediaChunk lastMediaChunk = mediaChunks.getLast();
+      BaseMediaChunk lastCompletedMediaChunk = lastMediaChunk != currentLoadable ? lastMediaChunk
+          : mediaChunks.size() > 1 ? mediaChunks.get(mediaChunks.size() - 2) : null;
+      if (lastCompletedMediaChunk != null) {
+        bufferedPositionUs = Math.max(bufferedPositionUs, lastCompletedMediaChunk.endTimeUs);
+      }
+      return Math.max(bufferedPositionUs, sampleQueue.getLargestQueuedTimestampUs());
     }
   }
 
@@ -236,8 +240,7 @@ public class ChunkSampleSource implements SampleSource, TrackStream, Loader.Call
     boolean seekInsideBuffer = !isPendingReset() && sampleQueue.skipToKeyframeBefore(positionUs);
     if (seekInsideBuffer) {
       // We succeeded. All we need to do is discard any chunks that we've moved past.
-      boolean haveSamples = !sampleQueue.isEmpty();
-      while (haveSamples && mediaChunks.size() > 1
+      while (mediaChunks.size() > 1
           && mediaChunks.get(1).getFirstSampleIndex() <= sampleQueue.getReadIndex()) {
         mediaChunks.removeFirst();
       }
@@ -286,9 +289,8 @@ public class ChunkSampleSource implements SampleSource, TrackStream, Loader.Call
       return NOTHING_READ;
     }
 
-    boolean haveSamples = !sampleQueue.isEmpty();
     BaseMediaChunk currentChunk = mediaChunks.getFirst();
-    while (haveSamples && mediaChunks.size() > 1
+    while (mediaChunks.size() > 1
         && mediaChunks.get(1).getFirstSampleIndex() <= sampleQueue.getReadIndex()) {
       mediaChunks.removeFirst();
       currentChunk = mediaChunks.getFirst();
@@ -300,15 +302,7 @@ public class ChunkSampleSource implements SampleSource, TrackStream, Loader.Call
       downstreamFormat = currentChunk.format;
     }
 
-    Format sampleFormat = sampleQueue.getDownstreamFormat();
-    if (sampleFormat != null && !sampleFormat.equals(downstreamSampleFormat)) {
-      formatHolder.format = sampleFormat;
-      formatHolder.drmInitData = currentChunk.getDrmInitData();
-      downstreamSampleFormat = sampleFormat;
-      return FORMAT_READ;
-    }
-
-    if (!haveSamples) {
+    if (sampleQueue.isEmpty()) {
       if (loadingFinished) {
         buffer.addFlag(C.BUFFER_FLAG_END_OF_STREAM);
         return BUFFER_READ;
@@ -316,6 +310,14 @@ public class ChunkSampleSource implements SampleSource, TrackStream, Loader.Call
       return NOTHING_READ;
     }
 
+    Format sampleFormat = sampleQueue.getDownstreamFormat();
+    if (!sampleFormat.equals(downstreamSampleFormat)) {
+      formatHolder.format = sampleFormat;
+      formatHolder.drmInitData = currentChunk.getDrmInitData();
+      downstreamSampleFormat = sampleFormat;
+      return FORMAT_READ;
+    }
+
     if (sampleQueue.readSample(buffer)) {
       if (buffer.timeUs < lastSeekPositionUs) {
         buffer.addFlag(C.BUFFER_FLAG_DECODE_ONLY);
@@ -327,7 +329,7 @@ public class ChunkSampleSource implements SampleSource, TrackStream, Loader.Call
     return NOTHING_READ;
   }
 
-  // Loadable.Callback implementation.
+  // Loader.Callback implementation.
 
   @Override
   public void onLoadCompleted(Loadable loadable) {
@@ -451,12 +453,10 @@ public class ChunkSampleSource implements SampleSource, TrackStream, Loader.Call
     currentLoadStartTimeMs = now;
     currentLoadable = nextLoadable;
     if (isMediaChunk(currentLoadable)) {
+      pendingResetPositionUs = C.UNSET_TIME_US;
       BaseMediaChunk mediaChunk = (BaseMediaChunk) currentLoadable;
       mediaChunk.init(sampleQueue);
       mediaChunks.add(mediaChunk);
-      if (isPendingReset()) {
-        pendingResetPositionUs = C.UNSET_TIME_US;
-      }
       eventDispatcher.loadStarted(mediaChunk.dataSpec.length, mediaChunk.type, mediaChunk.trigger,
           mediaChunk.format, mediaChunk.startTimeUs, mediaChunk.endTimeUs);
     } else {
@@ -480,6 +480,14 @@ public class ChunkSampleSource implements SampleSource, TrackStream, Loader.Call
     }
   }
 
+  private boolean isMediaChunk(Chunk chunk) {
+    return chunk instanceof BaseMediaChunk;
+  }
+
+  private boolean isPendingReset() {
+    return pendingResetPositionUs != C.UNSET_TIME_US;
+  }
+
   /**
    * Discard upstream media chunks until the queue length is equal to the length specified.
    *
@@ -504,12 +512,4 @@ public class ChunkSampleSource implements SampleSource, TrackStream, Loader.Call
     return true;
   }
 
-  private boolean isMediaChunk(Chunk chunk) {
-    return chunk instanceof BaseMediaChunk;
-  }
-
-  private boolean isPendingReset() {
-    return pendingResetPositionUs != C.UNSET_TIME_US;
-  }
-
 }