Report additional position discontinuities

- Properly report internal discontinuities
- Add DISCONTINUITY_REASON_SEEK_ADJUSTMENT to distinguish
  seek adjustments from other internal discontinuity events

-------------
Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=176367365

RELEASENOTES.md

@@ -11,6 +11,10 @@
 * SimpleExoPlayer: Support for multiple video, text and metadata outputs.
 * Support for `Renderer`s that don't consume any media
   ([#3212](https://github.com/google/ExoPlayer/issues/3212)).
+* Fix reporting of internal position discontinuities via
+  `Player.onPositionDiscontinuity`. `DISCONTINUITY_REASON_SEEK_ADJUSTMENT` is
+  added to disambiguate position adjustments during seeks from other types of
+  internal position discontinuity.
 * Fix potential `IndexOutOfBoundsException` when calling `ExoPlayer.getDuration`
   ([#3362](https://github.com/google/ExoPlayer/issues/3362)).
 * Fix playbacks involving looping, concatenation and ads getting stuck when

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

@@ -496,6 +496,8 @@ import java.util.Locale;
         return "PERIOD_TRANSITION";
       case Player.DISCONTINUITY_REASON_SEEK:
         return "SEEK";
+      case Player.DISCONTINUITY_REASON_SEEK_ADJUSTMENT:
+        return "SEEK_ADJUSTMENT";
       case Player.DISCONTINUITY_REASON_INTERNAL:
         return "INTERNAL";
       default:

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

@@ -473,7 +473,8 @@ import java.util.concurrent.CopyOnWriteArraySet;
       case ExoPlayerImplInternal.MSG_SOURCE_INFO_REFRESHED: {
         int prepareAcks = msg.arg1;
         int seekAcks = msg.arg2;
-        handlePlaybackInfo((PlaybackInfo) msg.obj, prepareAcks, seekAcks, false);
+        handlePlaybackInfo((PlaybackInfo) msg.obj, prepareAcks, seekAcks, false,
+            /* ignored */ DISCONTINUITY_REASON_INTERNAL);
         break;
       }
       case ExoPlayerImplInternal.MSG_TRACKS_CHANGED: {
@@ -491,11 +492,13 @@ import java.util.concurrent.CopyOnWriteArraySet;
       }
       case ExoPlayerImplInternal.MSG_SEEK_ACK: {
         boolean seekPositionAdjusted = msg.arg1 != 0;
-        handlePlaybackInfo((PlaybackInfo) msg.obj, 0, 1, seekPositionAdjusted);
+        handlePlaybackInfo((PlaybackInfo) msg.obj, 0, 1, seekPositionAdjusted,
+            DISCONTINUITY_REASON_SEEK_ADJUSTMENT);
         break;
       }
       case ExoPlayerImplInternal.MSG_POSITION_DISCONTINUITY: {
-        handlePlaybackInfo((PlaybackInfo) msg.obj, 0, 0, true);
+        @DiscontinuityReason int discontinuityReason = msg.arg1;
+        handlePlaybackInfo((PlaybackInfo) msg.obj, 0, 0, true, discontinuityReason);
         break;
       }
       case ExoPlayerImplInternal.MSG_PLAYBACK_PARAMETERS_CHANGED: {
@@ -521,7 +524,7 @@ import java.util.concurrent.CopyOnWriteArraySet;
   }
 
   private void handlePlaybackInfo(PlaybackInfo playbackInfo, int prepareAcks, int seekAcks,
-      boolean positionDiscontinuity) {
+      boolean positionDiscontinuity, @DiscontinuityReason int positionDiscontinuityReason) {
     Assertions.checkNotNull(playbackInfo.timeline);
     pendingPrepareAcks -= prepareAcks;
     pendingSeekAcks -= seekAcks;
@@ -542,9 +545,7 @@ import java.util.concurrent.CopyOnWriteArraySet;
       }
       if (positionDiscontinuity) {
         for (Player.EventListener listener : listeners) {
-          listener.onPositionDiscontinuity(
-              seekAcks > 0 ? DISCONTINUITY_REASON_INTERNAL : DISCONTINUITY_REASON_PERIOD_TRANSITION
-          );
+          listener.onPositionDiscontinuity(positionDiscontinuityReason);
         }
       }
     }

library/core/src/main/java/com/google/android/exoplayer2/ExoPlayerImplInternal.java

@@ -503,6 +503,10 @@ import java.io.IOException;
     long periodPositionUs = playingPeriodHolder.mediaPeriod.readDiscontinuity();
     if (periodPositionUs != C.TIME_UNSET) {
       resetRendererPosition(periodPositionUs);
+      playbackInfo = playbackInfo.fromNewPosition(playbackInfo.periodId, periodPositionUs,
+          playbackInfo.contentPositionUs);
+      eventHandler.obtainMessage(MSG_POSITION_DISCONTINUITY, Player.DISCONTINUITY_REASON_INTERNAL,
+          0, playbackInfo).sendToTarget();
     } else {
       // Use the standalone clock if there's no renderer clock, or if the providing renderer has
       // ended or needs the next sample stream to reenter the ready state. The latter case uses the
@@ -893,7 +897,10 @@ import java.io.IOException;
       long periodPositionUs = playingPeriodHolder.updatePeriodTrackSelection(
           playbackInfo.positionUs, recreateStreams, streamResetFlags);
       if (periodPositionUs != playbackInfo.positionUs) {
-        playbackInfo.positionUs = periodPositionUs;
+        playbackInfo = playbackInfo.fromNewPosition(playbackInfo.periodId, periodPositionUs,
+            playbackInfo.contentPositionUs);
+        eventHandler.obtainMessage(MSG_POSITION_DISCONTINUITY, Player.DISCONTINUITY_REASON_INTERNAL,
+            0, playbackInfo).sendToTarget();
         resetRendererPosition(periodPositionUs);
       }
 
@@ -1280,7 +1287,8 @@ import java.io.IOException;
       playbackInfo = playbackInfo.fromNewPosition(playingPeriodHolder.info.id,
           playingPeriodHolder.info.startPositionUs, playingPeriodHolder.info.contentPositionUs);
       updatePlaybackPositions();
-      eventHandler.obtainMessage(MSG_POSITION_DISCONTINUITY, playbackInfo).sendToTarget();
+      eventHandler.obtainMessage(MSG_POSITION_DISCONTINUITY,
+          Player.DISCONTINUITY_REASON_PERIOD_TRANSITION, 0, playbackInfo).sendToTarget();
     }
 
     if (readingPeriodHolder.info.isFinal) {

library/core/src/main/java/com/google/android/exoplayer2/Player.java

@@ -243,7 +243,7 @@ public interface Player {
    */
   @Retention(RetentionPolicy.SOURCE)
   @IntDef({DISCONTINUITY_REASON_PERIOD_TRANSITION, DISCONTINUITY_REASON_SEEK,
-      DISCONTINUITY_REASON_INTERNAL})
+      DISCONTINUITY_REASON_SEEK_ADJUSTMENT, DISCONTINUITY_REASON_INTERNAL})
   public @interface DiscontinuityReason {}
   /**
    * Automatic playback transition from one period in the timeline to the next. The period index may
@@ -254,10 +254,15 @@ public interface Player {
    * Seek within the current period or to another period.
    */
   int DISCONTINUITY_REASON_SEEK = 1;
+  /**
+   * Seek adjustment due to being unable to seek to the requested position or because the seek was
+   * permitted to be inexact.
+   */
+  int DISCONTINUITY_REASON_SEEK_ADJUSTMENT = 2;
   /**
    * Discontinuity introduced internally by the source.
    */
-  int DISCONTINUITY_REASON_INTERNAL = 2;
+  int DISCONTINUITY_REASON_INTERNAL = 3;
 
   /**
    * Register a listener to receive events from the player. The listener's methods will be called on