Yet more simplifications.

-------------
Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=118775612

demo/src/main/java/com/google/android/exoplayer/demo/player/DemoPlayer.java

@@ -31,11 +31,10 @@ import com.google.android.exoplayer.TimeRange;
 import com.google.android.exoplayer.TrackRenderer;
 import com.google.android.exoplayer.audio.AudioCapabilities;
 import com.google.android.exoplayer.audio.AudioTrack;
-import com.google.android.exoplayer.chunk.ChunkSampleSource;
+import com.google.android.exoplayer.chunk.ChunkSampleSourceEventListener;
 import com.google.android.exoplayer.dash.DashChunkSource;
 import com.google.android.exoplayer.drm.StreamingDrmSessionManager;
 import com.google.android.exoplayer.extractor.ExtractorSampleSource;
-import com.google.android.exoplayer.hls.HlsSampleSource;
 import com.google.android.exoplayer.metadata.MetadataTrackRenderer;
 import com.google.android.exoplayer.metadata.MetadataTrackRenderer.MetadataRenderer;
 import com.google.android.exoplayer.metadata.id3.Id3Frame;
@@ -65,12 +64,11 @@ import java.util.concurrent.CopyOnWriteArrayList;
  * SmoothStreaming and so on).
  */
 public class DemoPlayer implements ExoPlayer.Listener, DefaultTrackSelector.EventListener,
-    ChunkSampleSource.EventListener, HlsSampleSource.EventListener,
-    ExtractorSampleSource.EventListener, SingleSampleSource.EventListener,
-    DefaultBandwidthMeter.EventListener, MediaCodecVideoTrackRenderer.EventListener,
-    MediaCodecAudioTrackRenderer.EventListener, StreamingDrmSessionManager.EventListener,
-    DashChunkSource.EventListener, TextRenderer, MetadataRenderer<List<Id3Frame>>,
-    DebugTextViewHelper.Provider {
+    ChunkSampleSourceEventListener, ExtractorSampleSource.EventListener,
+    SingleSampleSource.EventListener, DefaultBandwidthMeter.EventListener,
+    MediaCodecVideoTrackRenderer.EventListener, MediaCodecAudioTrackRenderer.EventListener,
+    StreamingDrmSessionManager.EventListener, DashChunkSource.EventListener, TextRenderer,
+    MetadataRenderer<List<Id3Frame>>, DebugTextViewHelper.Provider {
 
   /**
    * Builds a source to play.

library/src/main/java/com/google/android/exoplayer/chunk/BaseChunkSampleSourceEventListener.java → library/src/main/java/com/google/android/exoplayer/chunk/ChunkSampleSourceEventListener.java

@@ -19,13 +19,16 @@ import com.google.android.exoplayer.C;
 import com.google.android.exoplayer.Format;
 import com.google.android.exoplayer.SampleSource;
 import com.google.android.exoplayer.TrackStream;
+import com.google.android.exoplayer.util.Util;
+
+import android.os.Handler;
 
 import java.io.IOException;
 
 /**
  * Interface for callbacks to be notified of chunk based {@link SampleSource} events.
  */
-public interface BaseChunkSampleSourceEventListener {
+public interface ChunkSampleSourceEventListener {
 
   /**
    * Invoked when an upstream load is started.
@@ -102,4 +105,96 @@ public interface BaseChunkSampleSourceEventListener {
    */
   void onDownstreamFormatChanged(int sourceId, Format format, int trigger, long mediaTimeMs);
 
+  /**
+   * Dispatches events to a {@link ChunkSampleSourceEventListener}.
+   */
+  final class EventDispatcher {
+
+    private final Handler handler;
+    private final ChunkSampleSourceEventListener listener;
+    private final int sourceId;
+
+    public EventDispatcher(Handler handler, ChunkSampleSourceEventListener listener, int sourceId) {
+      this.handler = listener != null ? handler : null;
+      this.listener = listener;
+      this.sourceId = sourceId;
+    }
+
+    public void loadStarted(final long length, final int type, final int trigger,
+        final Format format, final long mediaStartTimeUs, final long mediaEndTimeUs) {
+      if (listener != null) {
+        handler.post(new Runnable()  {
+          @Override
+          public void run() {
+            listener.onLoadStarted(sourceId, length, type, trigger, format,
+                Util.usToMs(mediaStartTimeUs), Util.usToMs(mediaEndTimeUs));
+          }
+        });
+      }
+    }
+
+    public void loadCompleted(final long bytesLoaded, final int type, final int trigger,
+        final Format format, final long mediaStartTimeUs, final long mediaEndTimeUs,
+        final long elapsedRealtimeMs, final long loadDurationMs) {
+      if (listener != null) {
+        handler.post(new Runnable()  {
+          @Override
+          public void run() {
+            listener.onLoadCompleted(sourceId, bytesLoaded, type, trigger, format,
+                Util.usToMs(mediaStartTimeUs), Util.usToMs(mediaEndTimeUs), elapsedRealtimeMs,
+                loadDurationMs);
+          }
+        });
+      }
+    }
+
+    public void loadCanceled(final long bytesLoaded) {
+      if (listener != null) {
+        handler.post(new Runnable()  {
+          @Override
+          public void run() {
+            listener.onLoadCanceled(sourceId, bytesLoaded);
+          }
+        });
+      }
+    }
+
+    public void loadError(final IOException e) {
+      if (listener != null) {
+        handler.post(new Runnable()  {
+          @Override
+          public void run() {
+            listener.onLoadError(sourceId, e);
+          }
+        });
+      }
+    }
+
+    public void upstreamDiscarded(final long mediaStartTimeUs, final long mediaEndTimeUs) {
+      if (listener != null) {
+        handler.post(new Runnable()  {
+          @Override
+          public void run() {
+            listener.onUpstreamDiscarded(sourceId, Util.usToMs(mediaStartTimeUs),
+                Util.usToMs(mediaEndTimeUs));
+          }
+        });
+      }
+    }
+
+    public void downstreamFormatChanged(final Format format, final int trigger,
+        final long positionUs) {
+      if (listener != null) {
+        handler.post(new Runnable()  {
+          @Override
+          public void run() {
+            listener.onDownstreamFormatChanged(sourceId, format, trigger,
+                Util.usToMs(positionUs));
+          }
+        });
+      }
+    }
+
+  }
+
 }

library/src/main/java/com/google/android/exoplayer/hls/HlsChunkSource.java

@@ -18,7 +18,6 @@ package com.google.android.exoplayer.hls;
 import com.google.android.exoplayer.BehindLiveWindowException;
 import com.google.android.exoplayer.C;
 import com.google.android.exoplayer.Format;
-import com.google.android.exoplayer.chunk.BaseChunkSampleSourceEventListener;
 import com.google.android.exoplayer.chunk.Chunk;
 import com.google.android.exoplayer.chunk.ChunkOperationHolder;
 import com.google.android.exoplayer.chunk.DataChunk;
@@ -57,11 +56,6 @@ import java.util.Locale;
  */
 public class HlsChunkSource {
 
-  /**
-   * Interface definition for a callback to be notified of {@link HlsChunkSource} events.
-   */
-  public interface EventListener extends BaseChunkSampleSourceEventListener {}
-
   public static final int TYPE_DEFAULT = 0;
   public static final int TYPE_AUDIO = 1;
   public static final int TYPE_SUBTITLE = 2;

library/src/main/java/com/google/android/exoplayer/hls/HlsSampleSource.java

@@ -25,14 +25,14 @@ import com.google.android.exoplayer.TrackGroup;
 import com.google.android.exoplayer.TrackGroupArray;
 import com.google.android.exoplayer.TrackSelection;
 import com.google.android.exoplayer.TrackStream;
-import com.google.android.exoplayer.chunk.BaseChunkSampleSourceEventListener;
 import com.google.android.exoplayer.chunk.Chunk;
 import com.google.android.exoplayer.chunk.ChunkOperationHolder;
+import com.google.android.exoplayer.chunk.ChunkSampleSourceEventListener;
+import com.google.android.exoplayer.chunk.ChunkSampleSourceEventListener.EventDispatcher;
 import com.google.android.exoplayer.upstream.Loader;
 import com.google.android.exoplayer.upstream.Loader.Loadable;
 import com.google.android.exoplayer.util.Assertions;
 import com.google.android.exoplayer.util.MimeTypes;
-import com.google.android.exoplayer.util.Util;
 
 import android.os.Handler;
 import android.os.SystemClock;
@@ -48,11 +48,6 @@ import java.util.List;
 public final class HlsSampleSource implements SampleSource, Loader.Callback {
 
   /**
-   * Interface definition for a callback to be notified of {@link HlsSampleSource} events.
-   */
-  public interface EventListener extends BaseChunkSampleSourceEventListener {}
-
-  /**
    * The default minimum number of times to retry loading data prior to failing.
    */
   public static final int DEFAULT_MIN_LOADABLE_RETRY_COUNT = 3;
@@ -69,11 +64,8 @@ public final class HlsSampleSource implements SampleSource, Loader.Callback {
   private final LinkedList<HlsExtractorWrapper> extractors;
   private final int bufferSizeContribution;
   private final ChunkOperationHolder chunkOperationHolder;
-
-  private final int eventSourceId;
+  private final EventDispatcher eventDispatcher;
   private final LoadControl loadControl;
-  private final Handler eventHandler;
-  private final EventListener eventListener;
 
   private boolean prepared;
   private boolean seenFirstTrackSelection;
@@ -108,23 +100,21 @@ public final class HlsSampleSource implements SampleSource, Loader.Callback {
   }
 
   public HlsSampleSource(HlsChunkSource chunkSource, LoadControl loadControl,
-      int bufferSizeContribution, Handler eventHandler, EventListener eventListener,
-      int eventSourceId) {
+      int bufferSizeContribution, Handler eventHandler,
+      ChunkSampleSourceEventListener eventListener, int eventSourceId) {
     this(chunkSource, loadControl, bufferSizeContribution, eventHandler, eventListener,
         eventSourceId, DEFAULT_MIN_LOADABLE_RETRY_COUNT);
   }
 
   public HlsSampleSource(HlsChunkSource chunkSource, LoadControl loadControl,
-      int bufferSizeContribution, Handler eventHandler, EventListener eventListener,
-      int eventSourceId, int minLoadableRetryCount) {
+      int bufferSizeContribution, Handler eventHandler,
+      ChunkSampleSourceEventListener eventListener, int eventSourceId, int minLoadableRetryCount) {
     this.chunkSource = chunkSource;
     this.loadControl = loadControl;
     this.bufferSizeContribution = bufferSizeContribution;
-    this.eventHandler = eventHandler;
-    this.eventListener = eventListener;
-    this.eventSourceId = eventSourceId;
     this.pendingResetPositionUs = NO_RESET_PENDING;
     loader = new Loader("Loader:HLS", minLoadableRetryCount);
+    eventDispatcher = new EventDispatcher(eventHandler, eventListener, eventSourceId);
     extractors = new LinkedList<>();
     chunkOperationHolder = new ChunkOperationHolder();
   }
@@ -336,7 +326,8 @@ public final class HlsSampleSource implements SampleSource, Loader.Callback {
 
     if (downstreamFormat == null || !downstreamFormat.equals(extractor.format)) {
       // Notify a change in the downstream format.
-      notifyDownstreamFormatChanged(extractor.format, extractor.trigger, extractor.startTimeUs);
+      eventDispatcher.downstreamFormatChanged(extractor.format, extractor.trigger,
+          extractor.startTimeUs);
       downstreamFormat = extractor.format;
     }
 
@@ -389,11 +380,11 @@ public final class HlsSampleSource implements SampleSource, Loader.Callback {
     if (isTsChunk(currentLoadable)) {
       Assertions.checkState(currentLoadable == currentTsLoadable);
       previousTsLoadable = currentTsLoadable;
-      notifyLoadCompleted(currentLoadable.bytesLoaded(), currentTsLoadable.type,
+      eventDispatcher.loadCompleted(currentLoadable.bytesLoaded(), currentTsLoadable.type,
           currentTsLoadable.trigger, currentTsLoadable.format, currentTsLoadable.startTimeUs,
           currentTsLoadable.endTimeUs, now, loadDurationMs);
     } else {
-      notifyLoadCompleted(currentLoadable.bytesLoaded(), currentLoadable.type,
+      eventDispatcher.loadCompleted(currentLoadable.bytesLoaded(), currentLoadable.type,
           currentLoadable.trigger, currentLoadable.format, -1, -1, now, loadDurationMs);
     }
     clearCurrentLoadable();
@@ -402,7 +393,7 @@ public final class HlsSampleSource implements SampleSource, Loader.Callback {
 
   @Override
   public void onLoadCanceled(Loadable loadable) {
-    notifyLoadCanceled(currentLoadable.bytesLoaded());
+    eventDispatcher.loadCanceled(currentLoadable.bytesLoaded());
     if (enabledTrackCount > 0) {
       restartFrom(pendingResetPositionUs);
     } else {
@@ -416,16 +407,16 @@ public final class HlsSampleSource implements SampleSource, Loader.Callback {
     long bytesLoaded = currentLoadable.bytesLoaded();
     boolean cancelable = !isTsChunk(currentLoadable) || bytesLoaded == 0;
     if (chunkSource.onChunkLoadError(currentLoadable, cancelable, e)) {
+      eventDispatcher.loadError(e);
+      eventDispatcher.loadCanceled(bytesLoaded);
+      clearCurrentLoadable();
       if (previousTsLoadable == null && !isPendingReset()) {
         pendingResetPositionUs = lastSeekPositionUs;
       }
-      clearCurrentLoadable();
-      notifyLoadError(e);
-      notifyLoadCanceled(bytesLoaded);
       maybeStartLoading();
       return Loader.DONT_RETRY;
     } else {
-      notifyLoadError(e);
+      eventDispatcher.loadError(e);
       return Loader.RETRY;
     }
   }
@@ -679,11 +670,11 @@ public final class HlsSampleSource implements SampleSource, Loader.Callback {
         extractorWrapper.init(loadControl.getAllocator());
         extractors.addLast(extractorWrapper);
       }
-      notifyLoadStarted(tsChunk.dataSpec.length, tsChunk.type, tsChunk.trigger, tsChunk.format,
-          tsChunk.startTimeUs, tsChunk.endTimeUs);
+      eventDispatcher.loadStarted(tsChunk.dataSpec.length, tsChunk.type, tsChunk.trigger,
+          tsChunk.format, tsChunk.startTimeUs, tsChunk.endTimeUs);
       currentTsLoadable = tsChunk;
     } else {
-      notifyLoadStarted(currentLoadable.dataSpec.length, currentLoadable.type,
+      eventDispatcher.loadStarted(currentLoadable.dataSpec.length, currentLoadable.type,
           currentLoadable.trigger, currentLoadable.format, -1, -1);
     }
     loader.startLoading(currentLoadable, this);
@@ -712,69 +703,6 @@ public final class HlsSampleSource implements SampleSource, Loader.Callback {
     return pendingResetPositionUs != NO_RESET_PENDING;
   }
 
-  private void notifyLoadStarted(final long length, final int type, final int trigger,
-      final Format format, final long mediaStartTimeUs, final long mediaEndTimeUs) {
-    if (eventHandler != null && eventListener != null) {
-      eventHandler.post(new Runnable()  {
-        @Override
-        public void run() {
-          eventListener.onLoadStarted(eventSourceId, length, type, trigger, format,
-              Util.usToMs(mediaStartTimeUs), Util.usToMs(mediaEndTimeUs));
-        }
-      });
-    }
-  }
-
-  private void notifyLoadCompleted(final long bytesLoaded, final int type, final int trigger,
-      final Format format, final long mediaStartTimeUs, final long mediaEndTimeUs,
-      final long elapsedRealtimeMs, final long loadDurationMs) {
-    if (eventHandler != null && eventListener != null) {
-      eventHandler.post(new Runnable()  {
-        @Override
-        public void run() {
-          eventListener.onLoadCompleted(eventSourceId, bytesLoaded, type, trigger, format,
-              Util.usToMs(mediaStartTimeUs), Util.usToMs(mediaEndTimeUs), elapsedRealtimeMs,
-              loadDurationMs);
-        }
-      });
-    }
-  }
-
-  private void notifyLoadCanceled(final long bytesLoaded) {
-    if (eventHandler != null && eventListener != null) {
-      eventHandler.post(new Runnable()  {
-        @Override
-        public void run() {
-          eventListener.onLoadCanceled(eventSourceId, bytesLoaded);
-        }
-      });
-    }
-  }
-
-  private void notifyLoadError(final IOException e) {
-    if (eventHandler != null && eventListener != null) {
-      eventHandler.post(new Runnable()  {
-        @Override
-        public void run() {
-          eventListener.onLoadError(eventSourceId, e);
-        }
-      });
-    }
-  }
-
-  private void notifyDownstreamFormatChanged(final Format format, final int trigger,
-      final long positionUs) {
-    if (eventHandler != null && eventListener != null) {
-      eventHandler.post(new Runnable()  {
-        @Override
-        public void run() {
-          eventListener.onDownstreamFormatChanged(eventSourceId, format, trigger,
-              Util.usToMs(positionUs));
-        }
-      });
-    }
-  }
-
   private final class TrackStreamImpl implements TrackStream {
 
     private final int group;