Minimal change to fix seeking before prepare + finalize API

- This change fixes seeking before the prepare (or more
  accurately, before the timeline is set). The fix a minimal
  one to fix the behavior. It's inefficient compared to
  posting the pending seek onto the playback thread, which
  will be the long term solution.
- As of this change, I think we can call V2 "done". There are
  some loose ends to tie up, but the API is effectively
  finalized and the implementation is in a state where you
  can take it, use it and expect it to work.

-------------
Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=132468107

demo/src/main/java/com/google/android/exoplayer2/demo/EventLogger.java

@@ -90,8 +90,8 @@ import java.util.Locale;
   }
 
   @Override
-  public void onPositionDiscontinuity(int periodIndex, long positionMs) {
+  public void onPositionDiscontinuity() {
-    Log.d(TAG, "discontinuity [" + periodIndex + ", " + positionMs + "]");
+    Log.d(TAG, "positionDiscontinuity");
   }
 
   @Override

demo/src/main/java/com/google/android/exoplayer2/demo/PlayerActivity.java

@@ -427,7 +427,7 @@ public class PlayerActivity extends Activity implements OnKeyListener, OnTouchLi
   }
 
   @Override
-  public void onPositionDiscontinuity(int periodIndex, long positionMs) {
+  public void onPositionDiscontinuity() {
     if (mediaController.isShowing()) {
       // The MediaController is visible, so force it to show the updated position immediately.
       mediaController.show();

extensions/flac/src/androidTest/java/com/google/android/exoplayer2/ext/flac/FlacPlaybackTest.java

@@ -91,7 +91,7 @@ public class FlacPlaybackTest extends InstrumentationTestCase {
     }
 
     @Override
-    public void onPositionDiscontinuity(int periodIndex, long positionMs) {
+    public void onPositionDiscontinuity() {
       // Do nothing.
     }
 

extensions/opus/src/androidTest/java/com/google/android/exoplayer2/ext/opus/OpusPlaybackTest.java

@@ -91,7 +91,7 @@ public class OpusPlaybackTest extends InstrumentationTestCase {
     }
 
     @Override
-    public void onPositionDiscontinuity(int periodIndex, long positionMs) {
+    public void onPositionDiscontinuity() {
       // Do nothing.
     }
 

extensions/vp9/src/androidTest/java/com/google/android/exoplayer2/ext/vp9/VpxPlaybackTest.java

@@ -110,7 +110,7 @@ public class VpxPlaybackTest extends InstrumentationTestCase {
     }
 
     @Override
-    public void onPositionDiscontinuity(int periodIndex, long positionMs) {
+    public void onPositionDiscontinuity() {
       // Do nothing.
     }
 

library/src/main/java/com/google/android/exoplayer2/ExoPlayer.java

@@ -144,15 +144,12 @@ public interface ExoPlayer {
      */
     void onPlayerError(ExoPlaybackException error);
 
-    // TODO: Should be windowIndex and position in the window.
     /**
-     * Called when the player's position changes due to a discontinuity (i.e. due to seeking,
+     * Called when a position discontinuity occurs. Position discontinuities occur when seeks are
-     * playback transitioning to the next window, or a source induced discontinuity).
+     * performed, when playbacks transition from one period in the timeline to the next, and when
-     *
+     * the player introduces discontinuities internally.
-     * @param periodIndex The index of the period being played.
-     * @param positionMs The playback position in that period, in milliseconds.
      */
-    void onPositionDiscontinuity(int periodIndex, long positionMs);
+    void onPositionDiscontinuity();
 
   }
 
@@ -309,17 +306,17 @@ public interface ExoPlayer {
   /**
    * Seeks to a position specified in milliseconds in the current window.
    *
-   * @param positionMs The seek position.
+   * @param windowPositionMs The seek position in the current window.
    */
-  void seekTo(long positionMs);
+  void seekTo(long windowPositionMs);
 
   /**
    * Seeks to a position specified in milliseconds in the specified window.
    *
    * @param windowIndex The index of the window.
-   * @param positionMs The seek position relative to the start of the window.
+   * @param windowPositionMs The seek position in the specified window.
    */
-  void seekTo(int windowIndex, long positionMs);
+  void seekTo(int windowIndex, long windowPositionMs);
 
   /**
    * Stops playback. Use {@code setPlayWhenReady(false)} rather than this method if the intention
@@ -356,11 +353,6 @@ public interface ExoPlayer {
    */
   void blockingSendMessages(ExoPlayerMessage... messages);
 
-  /**
-   * Returns the current {@link Timeline}, or {@code null} if there is no timeline.
-   */
-  Timeline getCurrentTimeline();
-
   /**
    * Returns the current manifest. The type depends on the {@link MediaSource} passed to
    * {@link #prepare}.
@@ -368,8 +360,17 @@ public interface ExoPlayer {
   Object getCurrentManifest();
 
   /**
-   * Returns the index of the window associated with the current period, or {@link C#INDEX_UNSET} if
+   * Returns the current {@link Timeline}, or {@code null} if there is no timeline.
-   * the timeline is not set.
+   */
+  Timeline getCurrentTimeline();
+
+  /**
+   * Returns the index of the period currently being played, or {@link C#INDEX_UNSET} if unknown.
+   */
+  int getCurrentPeriodIndex();
+
+  /**
+   * Returns the index of the window currently being played.
    */
   int getCurrentWindowIndex();
 
@@ -380,14 +381,13 @@ public interface ExoPlayer {
   long getDuration();
 
   /**
-   * Returns the playback position in the current window, in milliseconds, or {@link C#TIME_UNSET}
+   * Returns the playback position in the current window, in milliseconds.
-   * if the timeline is not set.
    */
   long getCurrentPosition();
 
   /**
-   * Returns an estimate of the position in the current window up to which data is buffered, or
+   * Returns an estimate of the position in the current window up to which data is buffered, in
-   * {@link C#TIME_UNSET} if no estimate is available.
+   * milliseconds.
    */
   long getBufferedPosition();
 

library/src/main/java/com/google/android/exoplayer2/ExoPlayerImpl.java

@@ -40,6 +40,7 @@ import java.util.concurrent.CopyOnWriteArraySet;
   private final Timeline.Window window;
   private final Timeline.Period period;
 
+  private boolean pendingInitialSeek;
   private boolean playWhenReady;
   private int playbackState;
   private int pendingSeekAcks;
@@ -137,7 +138,9 @@ import java.util.concurrent.CopyOnWriteArraySet;
   @Override
   public void seekToDefaultPosition(int windowIndex) {
     if (timeline == null) {
-      // TODO: Handle seeks before the timeline is set.
+      maskingWindowIndex = windowIndex;
+      maskingWindowPositionMs = C.TIME_UNSET;
+      pendingInitialSeek = true;
     } else {
       Assertions.checkIndex(windowIndex, 0, timeline.getWindowCount());
       pendingSeekAcks++;
@@ -157,7 +160,9 @@ import java.util.concurrent.CopyOnWriteArraySet;
     if (positionMs == C.TIME_UNSET) {
       seekToDefaultPosition(windowIndex);
     } else if (timeline == null) {
-      // TODO: Handle seeks before the timeline is set.
+      maskingWindowIndex = windowIndex;
+      maskingWindowPositionMs = positionMs;
+      pendingInitialSeek = true;
     } else {
       Assertions.checkIndex(windowIndex, 0, timeline.getWindowCount());
       pendingSeekAcks++;
@@ -174,7 +179,7 @@ import java.util.concurrent.CopyOnWriteArraySet;
       }
       internalPlayer.seekTo(periodIndex, C.msToUs(periodPositionMs));
       for (EventListener listener : listeners) {
-        listener.onPositionDiscontinuity(periodIndex, periodPositionMs);
+        listener.onPositionDiscontinuity();
       }
     }
   }
@@ -200,11 +205,14 @@ import java.util.concurrent.CopyOnWriteArraySet;
     internalPlayer.blockingSendMessages(messages);
   }
 
+  @Override
+  public int getCurrentPeriodIndex() {
+    return playbackInfo.periodIndex;
+  }
+
   @Override
   public int getCurrentWindowIndex() {
-    if (timeline == null) {
+    if (timeline == null || pendingSeekAcks > 0) {
-      return C.INDEX_UNSET;
-    } else if (pendingSeekAcks > 0) {
       return maskingWindowIndex;
     } else {
       return timeline.getPeriod(playbackInfo.periodIndex, period).windowIndex;
@@ -221,9 +229,7 @@ import java.util.concurrent.CopyOnWriteArraySet;
 
   @Override
   public long getCurrentPosition() {
-    if (timeline == null) {
+    if (timeline == null || pendingSeekAcks > 0) {
-      return C.TIME_UNSET;
-    } else if (pendingSeekAcks > 0) {
       return maskingWindowPositionMs;
     } else {
       timeline.getPeriod(playbackInfo.periodIndex, period);
@@ -234,9 +240,7 @@ import java.util.concurrent.CopyOnWriteArraySet;
   @Override
   public long getBufferedPosition() {
     // TODO - Implement this properly.
-    if (timeline == null) {
+    if (timeline == null || pendingSeekAcks > 0) {
-      return C.TIME_UNSET;
-    } else if (pendingSeekAcks > 0) {
       return maskingWindowPositionMs;
     } else {
       int periodIndex = playbackInfo.periodIndex;
@@ -293,9 +297,8 @@ import java.util.concurrent.CopyOnWriteArraySet;
       case ExoPlayerImplInternal.MSG_SEEK_ACK: {
         if (--pendingSeekAcks == 0) {
           playbackInfo = (ExoPlayerImplInternal.PlaybackInfo) msg.obj;
-          long positionMs = C.usToMs(playbackInfo.startPositionUs);
           for (EventListener listener : listeners) {
-            listener.onPositionDiscontinuity(playbackInfo.periodIndex, positionMs);
+            listener.onPositionDiscontinuity();
           }
         }
         break;
@@ -303,9 +306,8 @@ import java.util.concurrent.CopyOnWriteArraySet;
       case ExoPlayerImplInternal.MSG_POSITION_DISCONTINUITY: {
         if (pendingSeekAcks == 0) {
           playbackInfo = (ExoPlayerImplInternal.PlaybackInfo) msg.obj;
-          long positionMs = C.usToMs(playbackInfo.startPositionUs);
           for (EventListener listener : listeners) {
-            listener.onPositionDiscontinuity(playbackInfo.periodIndex, positionMs);
+            listener.onPositionDiscontinuity();
           }
         }
         break;
@@ -315,6 +317,10 @@ import java.util.concurrent.CopyOnWriteArraySet;
         Pair<Timeline, Object> timelineAndManifest = (Pair<Timeline, Object>) msg.obj;
         timeline = timelineAndManifest.first;
         manifest = timelineAndManifest.second;
+        if (pendingInitialSeek) {
+          pendingInitialSeek = false;
+          seekTo(maskingWindowIndex, maskingWindowPositionMs);
+        }
         for (EventListener listener : listeners) {
           listener.onTimelineChanged(timeline, manifest);
         }

library/src/main/java/com/google/android/exoplayer2/SimpleExoPlayer.java

@@ -460,6 +460,11 @@ public final class SimpleExoPlayer implements ExoPlayer {
     player.blockingSendMessages(messages);
   }
 
+  @Override
+  public int getCurrentPeriodIndex() {
+    return player.getCurrentPeriodIndex();
+  }
+
   @Override
   public int getCurrentWindowIndex() {
     return player.getCurrentWindowIndex();

library/src/main/java/com/google/android/exoplayer2/ui/DebugTextViewHelper.java

@@ -84,7 +84,7 @@ public final class DebugTextViewHelper implements Runnable, ExoPlayer.EventListe
   }
 
   @Override
-  public void onPositionDiscontinuity(int periodIndex, long positionMs) {
+  public void onPositionDiscontinuity() {
     updateAndPost();
   }
 

playbacktests/src/main/java/com/google/android/exoplayer2/playbacktests/util/ExoHostedTest.java

@@ -210,7 +210,7 @@ public abstract class ExoHostedTest implements HostedTest, ExoPlayer.EventListen
   }
 
   @Override
-  public final void onPositionDiscontinuity(int periodIndex, long positionMs) {
+  public final void onPositionDiscontinuity() {
     // Do nothing.
   }