Have seekTo return new position directly.

-------------
Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=125476407

library/src/main/java/com/google/android/exoplayer/ExoPlayerImplInternal.java

@@ -377,8 +377,8 @@ import java.util.concurrent.atomic.AtomicInteger;
     TraceUtil.beginSection("doSomeWork");
 
     if (enabledRenderers.length > 0) {
-      // Process reset if there is one, else update the position.
-      if (!checkForSourceResetInternal()) {
+      // Process a source discontinuity if there is one, else update the position.
+      if (!checkForSourceDiscontinuityInternal()) {
         updatePositionUs();
         sampleSource = timeline.getSampleSource();
       }
@@ -442,21 +442,21 @@ import java.util.concurrent.atomic.AtomicInteger;
     }
   }
 
-  private void seekToInternal(int sourceIndex, long positionMs) throws ExoPlaybackException {
+  private void seekToInternal(int sourceIndex, long seekPositionMs) throws ExoPlaybackException {
     try {
-      if (positionMs == (positionUs / 1000)) {
+      if (seekPositionMs == (positionUs / 1000)) {
         // Seek is to the current position. Do nothing.
         return;
       }
 
+      long seekPositionUs = seekPositionMs * 1000;
       rebuffering = false;
-      positionUs = positionMs * 1000;
-      internalPositionUs = sourceOffsetUs + positionUs;
       standaloneMediaClock.stop();
-      standaloneMediaClock.setPositionUs(internalPositionUs);
-      sampleSource = timeline.seekTo(sourceIndex, positionUs);
+
+      sampleSource = timeline.seekToSource(sourceIndex);
       if (sampleSource == null) {
         // The source isn't prepared.
+        setNewSourcePositionInternal(seekPositionUs);
         return;
       }
 
@@ -464,9 +464,10 @@ import java.util.concurrent.atomic.AtomicInteger;
         for (TrackRenderer renderer : enabledRenderers) {
           ensureStopped(renderer);
         }
-        checkForSourceResetInternal();
+        seekPositionUs = sampleSource.seekToUs(seekPositionUs);
       }
 
+      setNewSourcePositionInternal(seekPositionUs);
       resumeInternal();
     } finally {
       pendingSeekCount.decrementAndGet();
@@ -496,17 +497,22 @@ import java.util.concurrent.atomic.AtomicInteger;
     handler.sendEmptyMessage(MSG_DO_SOME_WORK);
   }
 
-  private boolean checkForSourceResetInternal() throws ExoPlaybackException {
-    long resetPositionUs = sampleSource.readReset();
-    if (resetPositionUs == C.UNSET_TIME_US) {
+  private boolean checkForSourceDiscontinuityInternal() throws ExoPlaybackException {
+    long newSourcePositionUs = sampleSource.readDiscontinuity();
+    if (newSourcePositionUs == C.UNSET_TIME_US) {
       return false;
     }
-    internalPositionUs = sourceOffsetUs + resetPositionUs;
+    setNewSourcePositionInternal(newSourcePositionUs);
+    return true;
+  }
+
+  private void setNewSourcePositionInternal(long sourcePositionUs) throws ExoPlaybackException {
+    positionUs = sourcePositionUs;
+    internalPositionUs = sourceOffsetUs + sourcePositionUs;
     standaloneMediaClock.setPositionUs(internalPositionUs);
     for (TrackRenderer renderer : enabledRenderers) {
       renderer.reset(internalPositionUs);
     }
-    return true;
   }
 
   private void stopInternal() {
@@ -672,8 +678,6 @@ import java.util.concurrent.atomic.AtomicInteger;
         playingSourceEndPositionUs = C.UNSET_TIME_US;
       } else if (playingSource.nextSource != null && playingSource.nextSource.prepared) {
         readingSource = playingSource.nextSource;
-        // Suppress reading a reset so that the transition can be seamless.
-        readingSource.sampleSource.readReset();
         // Replace enabled renderers' TrackStreams if they will continue to be enabled when the
         // new source starts playing, so that the transition can be seamless.
         TrackSelectionArray newTrackSelections = readingSource.trackSelections;
@@ -711,7 +715,7 @@ import java.util.concurrent.atomic.AtomicInteger;
       return playingSource.sampleSource;
     }
 
-    public SampleSource seekTo(int sourceIndex, long sourcePositionUs) throws ExoPlaybackException {
+    public SampleSource seekToSource(int sourceIndex) throws ExoPlaybackException {
       // Clear the timeline, but keep the requested source if it is already prepared.
       Source source = playingSource;
       Source newPlayingSource = null;
@@ -729,10 +733,8 @@ import java.util.concurrent.atomic.AtomicInteger;
         setPlayingSource(newPlayingSource, sourceOffsetUs);
         bufferingSource = playingSource;
         bufferingSourceOffsetUs = sourceOffsetUs;
-        if (playingSource.hasEnabledTracks) {
-          sampleSource.seekToUs(sourcePositionUs);
-        }
       } else {
+        // TODO[REFACTOR]: Presumably we need to disable the renderers somewhere in here?
         playingSource = null;
         readingSource = null;
         bufferingSource = null;

library/src/main/java/com/google/android/exoplayer/MultiSampleSource.java

@@ -124,17 +124,14 @@ public final class MultiSampleSource implements SampleSource {
   }
 
   @Override
-  public long readReset() {
-    long resetPositionUs = C.UNSET_TIME_US;
+  public long readDiscontinuity() {
     for (SampleSource source : enabledSources) {
-      long childResetPositionUs = source.readReset();
-      if (resetPositionUs == C.UNSET_TIME_US) {
-        resetPositionUs = childResetPositionUs;
-      } else if (childResetPositionUs != C.UNSET_TIME_US) {
-        resetPositionUs = Math.min(resetPositionUs, childResetPositionUs);
+      if (source.readDiscontinuity() != C.UNSET_TIME_US) {
+        // Children are not allowed to report discontinuities.
+        throw new IllegalStateException("Child reported discontinuity");
       }
     }
-    return resetPositionUs;
+    return C.UNSET_TIME_US;
   }
 
   @Override
@@ -150,10 +147,15 @@ public final class MultiSampleSource implements SampleSource {
   }
 
   @Override
-  public void seekToUs(long positionUs) {
-    for (SampleSource source : enabledSources) {
-      source.seekToUs(positionUs);
+  public long seekToUs(long positionUs) {
+    positionUs = enabledSources[0].seekToUs(positionUs);
+    for (int i = 1; i < enabledSources.length; i++) {
+      // Additional sources must seek to the same position.
+      if (enabledSources[i].seekToUs(positionUs) != positionUs) {
+        throw new IllegalStateException("Children seeked to different positions");
+      }
     }
+    return positionUs;
   }
 
   @Override

library/src/main/java/com/google/android/exoplayer/SampleSource.java

@@ -88,12 +88,15 @@ public interface SampleSource {
   void continueBuffering(long positionUs);
 
   /**
-   * Attempts to read a pending reset.
+   * Attempts to read a discontinuity.
+   * <p>
+   * After this method has returned a value other than {@link C#UNSET_TIME_US}, all
+   * {@link TrackStream}s provided by the source are guaranteed to start from a key frame.
    *
-   * @return If a reset was read then the playback position in microseconds after the reset. Else
-   *     {@link C#UNSET_TIME_US}.
+   * @return If a discontinuity was read then the playback position in microseconds after the
+   *     discontinuity. Else {@link C#UNSET_TIME_US}.
    */
-  long readReset();
+  long readDiscontinuity();
 
   /**
    * Returns an estimate of the position up to which data is buffered for the enabled tracks.
@@ -106,13 +109,17 @@ public interface SampleSource {
   long getBufferedPositionUs();
 
   /**
-   * Seeks to the specified position in microseconds.
+   * Attempts to seek to the specified position in microseconds.
+   * <p>
+   * After this method has been called, all {@link TrackStream}s provided by the source are
+   * guaranteed to start from a key frame.
    * <p>
    * This method should only be called when at least one track is selected.
    *
    * @param positionUs The seek position in microseconds.
+   * @return The actual position to which the source was seeked, in microseconds.
    */
-  void seekToUs(long positionUs);
+  long seekToUs(long positionUs);
 
   /**
    * Releases the source.

library/src/main/java/com/google/android/exoplayer/SingleSampleSource.java

@@ -74,7 +74,6 @@ public final class SingleSampleSource implements SampleSource, TrackStream,
   private final EventListener eventListener;
   private final int eventSourceId;
 
-  private long pendingResetPositionUs;
   private boolean loadingFinished;
 
   private int streamState;
@@ -140,7 +139,6 @@ public final class SingleSampleSource implements SampleSource, TrackStream,
     if (!newSelections.isEmpty()) {
       newStreams[0] = this;
       streamState = STREAM_STATE_SEND_FORMAT;
-      pendingResetPositionUs = C.UNSET_TIME_US;
       maybeStartLoading();
     }
     return newStreams;
@@ -157,11 +155,11 @@ public final class SingleSampleSource implements SampleSource, TrackStream,
   }
 
   @Override
-  public void seekToUs(long positionUs) {
+  public long seekToUs(long positionUs) {
     if (streamState == STREAM_STATE_END_OF_STREAM) {
-      pendingResetPositionUs = positionUs;
       streamState = STREAM_STATE_SEND_SAMPLE;
     }
+    return positionUs;
   }
 
   @Override
@@ -182,10 +180,8 @@ public final class SingleSampleSource implements SampleSource, TrackStream,
   }
 
   @Override
-  public long readReset() {
-    long resetPositionUs = pendingResetPositionUs;
-    pendingResetPositionUs = C.UNSET_TIME_US;
-    return resetPositionUs;
+  public long readDiscontinuity() {
+    return C.UNSET_TIME_US;
   }
 
   @Override

library/src/main/java/com/google/android/exoplayer/dash/DashSampleSource.java

@@ -92,8 +92,6 @@ public final class DashSampleSource implements SampleSource {
   private long elapsedRealtimeOffset;
   private TrackGroupArray trackGroups;
   private int[] trackGroupAdaptationSetIndices;
-  private boolean pendingReset;
-  private long lastSeekPositionUs;
   private ChunkTrackStream<DashChunkSource>[] trackStreams;
 
   public DashSampleSource(Uri manifestUri, DataSourceFactory dataSourceFactory,
@@ -184,14 +182,7 @@ public final class DashSampleSource implements SampleSource {
   }
 
   @Override
-  public long readReset() {
-    if (pendingReset) {
-      pendingReset = false;
-      for (ChunkTrackStream<DashChunkSource> trackStream : trackStreams) {
-        trackStream.setReadingEnabled(true);
-      }
-      return lastSeekPositionUs;
-    }
+  public long readDiscontinuity() {
     return C.UNSET_TIME_US;
   }
 
@@ -208,13 +199,11 @@ public final class DashSampleSource implements SampleSource {
   }
 
   @Override
-  public void seekToUs(long positionUs) {
-    lastSeekPositionUs = positionUs;
-    pendingReset = true;
+  public long seekToUs(long positionUs) {
     for (ChunkTrackStream<DashChunkSource> trackStream : trackStreams) {
-      trackStream.setReadingEnabled(false);
       trackStream.seekToUs(positionUs);
     }
+    return positionUs;
   }
 
   @Override

library/src/main/java/com/google/android/exoplayer/extractor/ExtractorSampleSource.java

@@ -388,7 +388,7 @@ public final class ExtractorSampleSource implements SampleSource, ExtractorOutpu
   }
 
   @Override
-  public long readReset() {
+  public long readDiscontinuity() {
     if (notifyReset) {
       notifyReset = false;
       return lastSeekPositionUs;
@@ -410,7 +410,7 @@ public final class ExtractorSampleSource implements SampleSource, ExtractorOutpu
   }
 
   @Override
-  public void seekToUs(long positionUs) {
+  public long seekToUs(long positionUs) {
     // Treat all seeks into non-seekable media as being to t=0.
     positionUs = seekMap.isSeekable() ? positionUs : 0;
     lastSeekPositionUs = positionUs;
@@ -426,6 +426,7 @@ public final class ExtractorSampleSource implements SampleSource, ExtractorOutpu
     if (!seekInsideBuffer) {
       restartFrom(positionUs);
     }
+    return positionUs;
   }
 
   @Override

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

@@ -80,8 +80,6 @@ public final class HlsSampleSource implements SampleSource,
   private int[] selectedTrackCounts;
   private HlsTrackStreamWrapper[] trackStreamWrappers;
   private HlsTrackStreamWrapper[] enabledTrackStreamWrappers;
-  private boolean pendingReset;
-  private long lastSeekPositionUs;
 
   public HlsSampleSource(Uri manifestUri, DataSourceFactory dataSourceFactory,
       BandwidthMeter bandwidthMeter, Handler eventHandler,
@@ -192,14 +190,7 @@ public final class HlsSampleSource implements SampleSource,
   }
 
   @Override
-  public long readReset() {
-    if (pendingReset) {
-      pendingReset = false;
-      for (HlsTrackStreamWrapper trackStreamWrapper : trackStreamWrappers) {
-        trackStreamWrapper.setReadingEnabled(true);
-      }
-      return lastSeekPositionUs;
-    }
+  public long readDiscontinuity() {
     return C.UNSET_TIME_US;
   }
 
@@ -216,16 +207,14 @@ public final class HlsSampleSource implements SampleSource,
   }
 
   @Override
-  public void seekToUs(long positionUs) {
+  public long seekToUs(long positionUs) {
     // Treat all seeks into non-seekable media as being to t=0.
     positionUs = isLive ? 0 : positionUs;
-    lastSeekPositionUs = positionUs;
-    pendingReset = true;
     timestampAdjusterProvider.reset();
     for (HlsTrackStreamWrapper trackStreamWrapper : enabledTrackStreamWrappers) {
-      trackStreamWrapper.setReadingEnabled(false);
       trackStreamWrapper.restartFrom(positionUs);
     }
+    return positionUs;
   }
 
   @Override

library/src/main/java/com/google/android/exoplayer/smoothstreaming/SmoothStreamingSampleSource.java

@@ -81,8 +81,6 @@ public final class SmoothStreamingSampleSource implements SampleSource,
   private TrackEncryptionBox[] trackEncryptionBoxes;
   private TrackGroupArray trackGroups;
   private int[] trackGroupElementIndices;
-  private boolean pendingReset;
-  private long lastSeekPositionUs;
 
   private ChunkTrackStream<SmoothStreamingChunkSource>[] trackStreams;
 
@@ -171,14 +169,7 @@ public final class SmoothStreamingSampleSource implements SampleSource,
   }
 
   @Override
-  public long readReset() {
-    if (pendingReset) {
-      pendingReset = false;
-      for (ChunkTrackStream<SmoothStreamingChunkSource> trackStream : trackStreams) {
-        trackStream.setReadingEnabled(true);
-      }
-      return lastSeekPositionUs;
-    }
+  public long readDiscontinuity() {
     return C.UNSET_TIME_US;
   }
 
@@ -195,13 +186,11 @@ public final class SmoothStreamingSampleSource implements SampleSource,
   }
 
   @Override
-  public void seekToUs(long positionUs) {
-    lastSeekPositionUs = positionUs;
-    pendingReset = true;
+  public long seekToUs(long positionUs) {
     for (ChunkTrackStream<SmoothStreamingChunkSource> trackStream : trackStreams) {
-      trackStream.setReadingEnabled(false);
       trackStream.seekToUs(positionUs);
     }
+    return positionUs;
   }
 
   @Override