Untangle PlayerInfo/PlaybackInfo updates

The methods in ExoPlayerImpl and MediaControllerImplBase that determine
the new PlayerInfo/PlaybackInfo currently have a hard-to-reason-about
setup where the method generating the new info accesses other methods
that rely on the existing class field instead of working with the
passed in PlayerInfo/PlaybackInfo. This prevents reuse of the util
methods (e.g. for replaceMediaItems) because they access potentially
stale state.

This change untangles these methods a bit by making the util methods
either static or at least ensure that they don't rely on existing
class fields of PlayerInfo/PlaybackInfo. Overall, the change is a
complete no-op.

#minor-release

PiperOrigin-RevId: 534036633

libraries/exoplayer/src/main/java/androidx/media3/exoplayer/ExoPlayerImpl.java

@@ -659,16 +659,7 @@ import java.util.concurrent.TimeoutException;
       setMediaSources(mediaSources, /* resetPosition= */ maskingWindowIndex == C.INDEX_UNSET);
       return;
     }
-    Timeline oldTimeline = getCurrentTimeline();
+    PlaybackInfo newPlaybackInfo = addMediaSourcesInternal(playbackInfo, index, mediaSources);
-    pendingOperationAcks++;
-    List<MediaSourceList.MediaSourceHolder> holders = addMediaSourceHolders(index, mediaSources);
-    Timeline newTimeline = createMaskingTimeline();
-    PlaybackInfo newPlaybackInfo =
-        maskTimelineAndPosition(
-            playbackInfo,
-            newTimeline,
-            getPeriodPositionUsAfterTimelineChanged(oldTimeline, newTimeline));
-    internalPlayer.addMediaSources(index, holders, shuffleOrder);
     updatePlaybackInfo(
         newPlaybackInfo,
         /* timelineChangeReason= */ TIMELINE_CHANGE_REASON_PLAYLIST_CHANGED,
@@ -691,7 +682,7 @@ import java.util.concurrent.TimeoutException;
       // Do nothing.
       return;
     }
-    PlaybackInfo newPlaybackInfo = removeMediaItemsInternal(fromIndex, toIndex);
+    PlaybackInfo newPlaybackInfo = removeMediaItemsInternal(playbackInfo, fromIndex, toIndex);
     boolean positionDiscontinuity =
         !newPlaybackInfo.periodId.periodUid.equals(playbackInfo.periodId.periodUid);
     updatePlaybackInfo(
@@ -725,7 +716,11 @@ import java.util.concurrent.TimeoutException;
         maskTimelineAndPosition(
             playbackInfo,
             newTimeline,
-            getPeriodPositionUsAfterTimelineChanged(oldTimeline, newTimeline));
+            getPeriodPositionUsAfterTimelineChanged(
+                oldTimeline,
+                newTimeline,
+                getCurrentWindowIndexInternal(playbackInfo),
+                getContentPositionInternal(playbackInfo)));
     internalPlayer.moveMediaSources(fromIndex, toIndex, newFromIndex, shuffleOrder);
     updatePlaybackInfo(
         newPlaybackInfo,
@@ -1057,7 +1052,7 @@ import java.util.concurrent.TimeoutException;
   @Override
   public int getCurrentMediaItemIndex() {
     verifyApplicationThread();
-    int currentWindowIndex = getCurrentWindowIndexInternal();
+    int currentWindowIndex = getCurrentWindowIndexInternal(playbackInfo);
     return currentWindowIndex == C.INDEX_UNSET ? 0 : currentWindowIndex;
   }
 
@@ -1117,17 +1112,7 @@ import java.util.concurrent.TimeoutException;
   @Override
   public long getContentPosition() {
     verifyApplicationThread();
-    if (isPlayingAd()) {
+    return getContentPositionInternal(playbackInfo);
-      playbackInfo.timeline.getPeriodByUid(playbackInfo.periodId.periodUid, period);
-      return playbackInfo.requestedContentPositionUs == C.TIME_UNSET
-          ? playbackInfo
-              .timeline
-              .getWindow(getCurrentMediaItemIndex(), window)
-              .getDefaultPositionMs()
-          : period.getPositionInWindowMs() + Util.usToMs(playbackInfo.requestedContentPositionUs);
-    } else {
-      return getCurrentPosition();
-    }
   }
 
   @Override
@@ -1853,13 +1838,25 @@ import java.util.concurrent.TimeoutException;
         /* repeatCurrentMediaItem= */ false);
   }
 
-  private int getCurrentWindowIndexInternal() {
+  private int getCurrentWindowIndexInternal(PlaybackInfo playbackInfo) {
     if (playbackInfo.timeline.isEmpty()) {
       return maskingWindowIndex;
-    } else {
-      return playbackInfo.timeline.getPeriodByUid(playbackInfo.periodId.periodUid, period)
-          .windowIndex;
     }
+    return playbackInfo.timeline.getPeriodByUid(playbackInfo.periodId.periodUid, period)
+        .windowIndex;
+  }
+
+  private long getContentPositionInternal(PlaybackInfo playbackInfo) {
+    if (playbackInfo.periodId.isAd()) {
+      playbackInfo.timeline.getPeriodByUid(playbackInfo.periodId.periodUid, period);
+      return playbackInfo.requestedContentPositionUs == C.TIME_UNSET
+          ? playbackInfo
+              .timeline
+              .getWindow(getCurrentWindowIndexInternal(playbackInfo), window)
+              .getDefaultPositionMs()
+          : period.getPositionInWindowMs() + Util.usToMs(playbackInfo.requestedContentPositionUs);
+    }
+    return Util.usToMs(getCurrentPositionUsInternal(playbackInfo));
   }
 
   private long getCurrentPositionUsInternal(PlaybackInfo playbackInfo) {
@@ -1874,10 +1871,9 @@ import java.util.concurrent.TimeoutException;
 
     if (playbackInfo.periodId.isAd()) {
       return positionUs;
-    } else {
-      return periodPositionUsToWindowPositionUs(
-          playbackInfo.timeline, playbackInfo.periodId, positionUs);
     }
+    return periodPositionUsToWindowPositionUs(
+        playbackInfo.timeline, playbackInfo.periodId, positionUs);
   }
 
   private List<MediaSource> createMediaSources(List<MediaItem> mediaItems) {
@@ -2276,7 +2272,7 @@ import java.util.concurrent.TimeoutException;
       int startWindowIndex,
       long startPositionMs,
       boolean resetToDefaultPosition) {
-    int currentWindowIndex = getCurrentWindowIndexInternal();
+    int currentWindowIndex = getCurrentWindowIndexInternal(playbackInfo);
     long currentPositionMs = getCurrentPosition();
     pendingOperationAcks++;
     if (!mediaSourceHolderSnapshots.isEmpty()) {
@@ -2347,9 +2343,30 @@ import java.util.concurrent.TimeoutException;
     return holders;
   }
 
-  private PlaybackInfo removeMediaItemsInternal(int fromIndex, int toIndex) {
+  private PlaybackInfo addMediaSourcesInternal(
-    int currentIndex = getCurrentMediaItemIndex();
+      PlaybackInfo playbackInfo, int index, List<MediaSource> mediaSources) {
-    Timeline oldTimeline = getCurrentTimeline();
+    Timeline oldTimeline = playbackInfo.timeline;
+    pendingOperationAcks++;
+    List<MediaSourceList.MediaSourceHolder> holders = addMediaSourceHolders(index, mediaSources);
+    Timeline newTimeline = createMaskingTimeline();
+    PlaybackInfo newPlaybackInfo =
+        maskTimelineAndPosition(
+            playbackInfo,
+            newTimeline,
+            getPeriodPositionUsAfterTimelineChanged(
+                oldTimeline,
+                newTimeline,
+                getCurrentWindowIndexInternal(playbackInfo),
+                getContentPositionInternal(playbackInfo)));
+    internalPlayer.addMediaSources(index, holders, shuffleOrder);
+    return newPlaybackInfo;
+  }
+
+  private PlaybackInfo removeMediaItemsInternal(
+      PlaybackInfo playbackInfo, int fromIndex, int toIndex) {
+    int currentIndex = getCurrentWindowIndexInternal(playbackInfo);
+    long contentPositionMs = getContentPositionInternal(playbackInfo);
+    Timeline oldTimeline = playbackInfo.timeline;
     int currentMediaSourceCount = mediaSourceHolderSnapshots.size();
     pendingOperationAcks++;
     removeMediaSourceHolders(fromIndex, /* toIndexExclusive= */ toIndex);
@@ -2358,7 +2375,8 @@ import java.util.concurrent.TimeoutException;
         maskTimelineAndPosition(
             playbackInfo,
             newTimeline,
-            getPeriodPositionUsAfterTimelineChanged(oldTimeline, newTimeline));
+            getPeriodPositionUsAfterTimelineChanged(
+                oldTimeline, newTimeline, currentIndex, contentPositionMs));
     // Player transitions to STATE_ENDED if the current index is part of the removed tail.
     final boolean transitionsToEnded =
         newPlaybackInfo.playbackState != STATE_IDLE
@@ -2387,7 +2405,9 @@ import java.util.concurrent.TimeoutException;
   private PlaybackInfo maskTimelineAndPosition(
       PlaybackInfo playbackInfo, Timeline timeline, @Nullable Pair<Object, Long> periodPositionUs) {
     checkArgument(timeline.isEmpty() || periodPositionUs != null);
+    // Get the old timeline and position before updating playbackInfo.
     Timeline oldTimeline = playbackInfo.timeline;
+    long oldContentPositionMs = getContentPositionInternal(playbackInfo);
     // Mask the timeline.
     playbackInfo = playbackInfo.copyWithTimeline(timeline);
 
@@ -2415,7 +2435,7 @@ import java.util.concurrent.TimeoutException;
     MediaPeriodId newPeriodId =
         playingPeriodChanged ? new MediaPeriodId(periodPositionUs.first) : playbackInfo.periodId;
     long newContentPositionUs = periodPositionUs.second;
-    long oldContentPositionUs = Util.msToUs(getContentPosition());
+    long oldContentPositionUs = Util.msToUs(oldContentPositionMs);
     if (!oldTimeline.isEmpty()) {
       oldContentPositionUs -=
           oldTimeline.getPeriodByUid(oldPeriodUid, period).getPositionInWindowUs();
@@ -2491,20 +2511,21 @@ import java.util.concurrent.TimeoutException;
 
   @Nullable
   private Pair<Object, Long> getPeriodPositionUsAfterTimelineChanged(
-      Timeline oldTimeline, Timeline newTimeline) {
+      Timeline oldTimeline,
-    long currentPositionMs = getContentPosition();
+      Timeline newTimeline,
+      int currentWindowIndexInternal,
+      long contentPositionMs) {
     if (oldTimeline.isEmpty() || newTimeline.isEmpty()) {
       boolean isCleared = !oldTimeline.isEmpty() && newTimeline.isEmpty();
       return maskWindowPositionMsOrGetPeriodPositionUs(
           newTimeline,
-          isCleared ? C.INDEX_UNSET : getCurrentWindowIndexInternal(),
+          isCleared ? C.INDEX_UNSET : currentWindowIndexInternal,
-          isCleared ? C.TIME_UNSET : currentPositionMs);
+          isCleared ? C.TIME_UNSET : contentPositionMs);
     }
-    int currentMediaItemIndex = getCurrentMediaItemIndex();
     @Nullable
     Pair<Object, Long> oldPeriodPositionUs =
         oldTimeline.getPeriodPositionUs(
-            window, period, currentMediaItemIndex, Util.msToUs(currentPositionMs));
+            window, period, currentWindowIndexInternal, Util.msToUs(contentPositionMs));
     Object periodUid = castNonNull(oldPeriodPositionUs).first;
     if (newTimeline.getIndexOfPeriod(periodUid) != C.INDEX_UNSET) {
       // The old period position is still available in the new timeline.
@@ -2556,7 +2577,7 @@ import java.util.concurrent.TimeoutException;
   }
 
   private PlayerMessage createMessageInternal(Target target) {
-    int currentWindowIndex = getCurrentWindowIndexInternal();
+    int currentWindowIndex = getCurrentWindowIndexInternal(playbackInfo);
     return new PlayerMessage(
         internalPlayer,
         target,

libraries/session/src/main/java/androidx/media3/session/MediaControllerImplBase.java

@@ -920,7 +920,19 @@ import org.checkerframework.checker.nullness.qual.NonNull;
     }
     // Add media items to the end of the timeline if the index exceeds the window count.
     index = min(index, playerInfo.timeline.getWindowCount());
+    PlayerInfo newPlayerInfo = maskPlaybackInfoForAddedItems(playerInfo, index, mediaItems);
+    updatePlayerInfo(
+        newPlayerInfo,
+        /* timelineChangeReason= */ Player.TIMELINE_CHANGE_REASON_PLAYLIST_CHANGED,
+        /* ignored */ Player.PLAY_WHEN_READY_CHANGE_REASON_USER_REQUEST,
+        /* positionDiscontinuity= */ false,
+        /* ignored */ Player.DISCONTINUITY_REASON_INTERNAL,
+        /* mediaItemTransition= */ playerInfo.timeline.isEmpty(),
+        Player.MEDIA_ITEM_TRANSITION_REASON_PLAYLIST_CHANGED);
+  }
 
+  private static PlayerInfo maskPlaybackInfoForAddedItems(
+      PlayerInfo playerInfo, int index, List<MediaItem> mediaItems) {
     Timeline oldTimeline = playerInfo.timeline;
     List<Window> newWindows = new ArrayList<>();
     List<Period> newPeriods = new ArrayList<>();
@@ -948,21 +960,12 @@ import org.checkerframework.checker.nullness.qual.NonNull;
               ? playerInfo.sessionPositionInfo.positionInfo.periodIndex + mediaItems.size()
               : playerInfo.sessionPositionInfo.positionInfo.periodIndex;
     }
-    PlayerInfo newPlayerInfo =
+    return maskTimelineAndPositionInfo(
-        maskTimelineAndPositionInfo(
+        playerInfo,
-            playerInfo,
+        newTimeline,
-            newTimeline,
+        newMediaItemIndex,
-            newMediaItemIndex,
+        newPeriodIndex,
-            newPeriodIndex,
+        Player.DISCONTINUITY_REASON_INTERNAL);
-            Player.DISCONTINUITY_REASON_INTERNAL);
-    updatePlayerInfo(
-        newPlayerInfo,
-        /* timelineChangeReason= */ Player.TIMELINE_CHANGE_REASON_PLAYLIST_CHANGED,
-        /* ignored */ Player.PLAY_WHEN_READY_CHANGE_REASON_USER_REQUEST,
-        /* positionDiscontinuity= */ false,
-        /* ignored */ Player.DISCONTINUITY_REASON_INTERNAL,
-        /* mediaItemTransition= */ oldTimeline.isEmpty(),
-        Player.MEDIA_ITEM_TRANSITION_REASON_PLAYLIST_CHANGED);
   }
 
   @Override
@@ -1004,13 +1007,29 @@ import org.checkerframework.checker.nullness.qual.NonNull;
   }
 
   private void removeMediaItemsInternal(int fromIndex, int toIndex) {
-    Timeline oldTimeline = playerInfo.timeline;
     int playlistSize = playerInfo.timeline.getWindowCount();
     toIndex = min(toIndex, playlistSize);
-    if (fromIndex >= playlistSize || fromIndex == toIndex) {
+    if (fromIndex >= playlistSize || fromIndex == toIndex || playlistSize == 0) {
       return;
     }
+    boolean currentItemRemoved =
+        getCurrentMediaItemIndex() >= fromIndex && getCurrentMediaItemIndex() < toIndex;
+    PlayerInfo newPlayerInfo = maskPlayerInfoForRemovedItems(playerInfo, fromIndex, toIndex);
+    updatePlayerInfo(
+        newPlayerInfo,
+        /* timelineChangeReason= */ Player.TIMELINE_CHANGE_REASON_PLAYLIST_CHANGED,
+        /* ignored */ Player.PLAY_WHEN_READY_CHANGE_REASON_USER_REQUEST,
+        /* positionDiscontinuity= */ currentItemRemoved,
+        Player.DISCONTINUITY_REASON_REMOVE,
+        /* mediaItemTransition= */ playerInfo.sessionPositionInfo.positionInfo.mediaItemIndex
+                >= fromIndex
+            && playerInfo.sessionPositionInfo.positionInfo.mediaItemIndex < toIndex,
+        Player.MEDIA_ITEM_TRANSITION_REASON_PLAYLIST_CHANGED);
+  }
 
+  private static PlayerInfo maskPlayerInfoForRemovedItems(
+      PlayerInfo playerInfo, int fromIndex, int toIndex) {
+    Timeline oldTimeline = playerInfo.timeline;
     List<Window> newWindows = new ArrayList<>();
     List<Period> newPeriods = new ArrayList<>();
     for (int i = 0; i < oldTimeline.getWindowCount(); i++) {
@@ -1021,124 +1040,109 @@ import org.checkerframework.checker.nullness.qual.NonNull;
     rebuildPeriods(oldTimeline, newWindows, newPeriods);
     Timeline newTimeline = createMaskingTimeline(newWindows, newPeriods);
 
-    int oldMediaItemIndex = getCurrentMediaItemIndex();
+    int oldMediaItemIndex = getCurrentMediaItemIndexInternal(playerInfo);
     int newMediaItemIndex = oldMediaItemIndex;
     int oldPeriodIndex = playerInfo.sessionPositionInfo.positionInfo.periodIndex;
     int newPeriodIndex = oldPeriodIndex;
-    boolean currentItemRemoved =
-        getCurrentMediaItemIndex() >= fromIndex && getCurrentMediaItemIndex() < toIndex;
     Window window = new Window();
-    if (oldTimeline.isEmpty()) {
+    boolean currentItemRemoved = oldMediaItemIndex >= fromIndex && oldMediaItemIndex < toIndex;
-      // No masking required. Just forwarding command to session.
+    if (newTimeline.isEmpty()) {
+      newMediaItemIndex = C.INDEX_UNSET;
+      newPeriodIndex = 0;
     } else {
-      if (newTimeline.isEmpty()) {
-        newMediaItemIndex = C.INDEX_UNSET;
-        newPeriodIndex = 0;
-      } else {
-        if (currentItemRemoved) {
-          int oldNextMediaItemIndex =
-              resolveSubsequentMediaItemIndex(
-                  getRepeatMode(),
-                  getShuffleModeEnabled(),
-                  oldMediaItemIndex,
-                  oldTimeline,
-                  fromIndex,
-                  toIndex);
-          if (oldNextMediaItemIndex == C.INDEX_UNSET) {
-            newMediaItemIndex = newTimeline.getFirstWindowIndex(getShuffleModeEnabled());
-          } else if (oldNextMediaItemIndex >= toIndex) {
-            newMediaItemIndex = oldNextMediaItemIndex - (toIndex - fromIndex);
-          } else {
-            newMediaItemIndex = oldNextMediaItemIndex;
-          }
-          newPeriodIndex = newTimeline.getWindow(newMediaItemIndex, window).firstPeriodIndex;
-        } else if (oldMediaItemIndex >= toIndex) {
-          newMediaItemIndex -= (toIndex - fromIndex);
-          newPeriodIndex =
-              getNewPeriodIndexWithoutRemovedPeriods(
-                  oldTimeline, oldPeriodIndex, fromIndex, toIndex);
-        }
-      }
-
-      PlayerInfo newPlayerInfo;
       if (currentItemRemoved) {
-        PositionInfo newPositionInfo;
+        int oldNextMediaItemIndex =
-        if (newMediaItemIndex == C.INDEX_UNSET) {
+            resolveSubsequentMediaItemIndex(
-          newPositionInfo = SessionPositionInfo.DEFAULT_POSITION_INFO;
+                playerInfo.repeatMode,
-          newPlayerInfo =
+                playerInfo.shuffleModeEnabled,
-              maskTimelineAndPositionInfo(
+                oldMediaItemIndex,
-                  playerInfo,
+                oldTimeline,
-                  newTimeline,
+                fromIndex,
-                  newPositionInfo,
+                toIndex);
-                  SessionPositionInfo.DEFAULT,
+        if (oldNextMediaItemIndex == C.INDEX_UNSET) {
-                  Player.DISCONTINUITY_REASON_REMOVE);
+          newMediaItemIndex = newTimeline.getFirstWindowIndex(playerInfo.shuffleModeEnabled);
+        } else if (oldNextMediaItemIndex >= toIndex) {
+          newMediaItemIndex = oldNextMediaItemIndex - (toIndex - fromIndex);
         } else {
-          Window newWindow = newTimeline.getWindow(newMediaItemIndex, new Window());
+          newMediaItemIndex = oldNextMediaItemIndex;
-          long defaultPositionMs = newWindow.getDefaultPositionMs();
-          long durationMs = newWindow.getDurationMs();
-          newPositionInfo =
-              new PositionInfo(
-                  /* windowUid= */ null,
-                  newMediaItemIndex,
-                  newWindow.mediaItem,
-                  /* periodUid= */ null,
-                  newPeriodIndex,
-                  /* positionMs= */ defaultPositionMs,
-                  /* contentPositionMs= */ defaultPositionMs,
-                  /* adGroupIndex= */ C.INDEX_UNSET,
-                  /* adIndexInAdGroup= */ C.INDEX_UNSET);
-          newPlayerInfo =
-              maskTimelineAndPositionInfo(
-                  playerInfo,
-                  newTimeline,
-                  newPositionInfo,
-                  new SessionPositionInfo(
-                      newPositionInfo,
-                      /* isPlayingAd= */ false,
-                      /* eventTimeMs= */ SystemClock.elapsedRealtime(),
-                      /* durationMs= */ durationMs,
-                      /* bufferedPositionMs= */ defaultPositionMs,
-                      /* bufferedPercentage= */ calculateBufferedPercentage(
-                          defaultPositionMs, durationMs),
-                      /* totalBufferedDurationMs= */ 0,
-                      /* currentLiveOffsetMs= */ C.TIME_UNSET,
-                      /* contentDurationMs= */ durationMs,
-                      /* contentBufferedPositionMs= */ defaultPositionMs),
-                  Player.DISCONTINUITY_REASON_REMOVE);
         }
-      } else {
+        newPeriodIndex = newTimeline.getWindow(newMediaItemIndex, window).firstPeriodIndex;
+      } else if (oldMediaItemIndex >= toIndex) {
+        newMediaItemIndex -= (toIndex - fromIndex);
+        newPeriodIndex =
+            getNewPeriodIndexWithoutRemovedPeriods(oldTimeline, oldPeriodIndex, fromIndex, toIndex);
+      }
+    }
+
+    PlayerInfo newPlayerInfo;
+    if (currentItemRemoved) {
+      PositionInfo newPositionInfo;
+      if (newMediaItemIndex == C.INDEX_UNSET) {
+        newPositionInfo = SessionPositionInfo.DEFAULT_POSITION_INFO;
         newPlayerInfo =
             maskTimelineAndPositionInfo(
                 playerInfo,
                 newTimeline,
+                newPositionInfo,
+                SessionPositionInfo.DEFAULT,
+                Player.DISCONTINUITY_REASON_REMOVE);
+      } else {
+        Window newWindow = newTimeline.getWindow(newMediaItemIndex, new Window());
+        long defaultPositionMs = newWindow.getDefaultPositionMs();
+        long durationMs = newWindow.getDurationMs();
+        newPositionInfo =
+            new PositionInfo(
+                /* windowUid= */ null,
                 newMediaItemIndex,
+                newWindow.mediaItem,
+                /* periodUid= */ null,
                 newPeriodIndex,
+                /* positionMs= */ defaultPositionMs,
+                /* contentPositionMs= */ defaultPositionMs,
+                /* adGroupIndex= */ C.INDEX_UNSET,
+                /* adIndexInAdGroup= */ C.INDEX_UNSET);
+        newPlayerInfo =
+            maskTimelineAndPositionInfo(
+                playerInfo,
+                newTimeline,
+                newPositionInfo,
+                new SessionPositionInfo(
+                    newPositionInfo,
+                    /* isPlayingAd= */ false,
+                    /* eventTimeMs= */ SystemClock.elapsedRealtime(),
+                    /* durationMs= */ durationMs,
+                    /* bufferedPositionMs= */ defaultPositionMs,
+                    /* bufferedPercentage= */ calculateBufferedPercentage(
+                        defaultPositionMs, durationMs),
+                    /* totalBufferedDurationMs= */ 0,
+                    /* currentLiveOffsetMs= */ C.TIME_UNSET,
+                    /* contentDurationMs= */ durationMs,
+                    /* contentBufferedPositionMs= */ defaultPositionMs),
                 Player.DISCONTINUITY_REASON_REMOVE);
       }
-
+    } else {
-      // Player transitions to Player.STATE_ENDED if the current index is part of the removed tail.
+      newPlayerInfo =
-      final boolean transitionsToEnded =
+          maskTimelineAndPositionInfo(
-          newPlayerInfo.playbackState != Player.STATE_IDLE
+              playerInfo,
-              && newPlayerInfo.playbackState != Player.STATE_ENDED
+              newTimeline,
-              && fromIndex < toIndex
+              newMediaItemIndex,
-              && toIndex == oldTimeline.getWindowCount()
+              newPeriodIndex,
-              && getCurrentMediaItemIndex() >= fromIndex;
+              Player.DISCONTINUITY_REASON_REMOVE);
-      if (transitionsToEnded) {
-        newPlayerInfo =
-            newPlayerInfo.copyWithPlaybackState(Player.STATE_ENDED, /* playerError= */ null);
-      }
-
-      updatePlayerInfo(
-          newPlayerInfo,
-          /* timelineChangeReason= */ Player.TIMELINE_CHANGE_REASON_PLAYLIST_CHANGED,
-          /* ignored */ Player.PLAY_WHEN_READY_CHANGE_REASON_USER_REQUEST,
-          /* positionDiscontinuity= */ currentItemRemoved,
-          Player.DISCONTINUITY_REASON_REMOVE,
-          /* mediaItemTransition= */ playerInfo.sessionPositionInfo.positionInfo.mediaItemIndex
-                  >= fromIndex
-              && playerInfo.sessionPositionInfo.positionInfo.mediaItemIndex < toIndex,
-          Player.MEDIA_ITEM_TRANSITION_REASON_PLAYLIST_CHANGED);
     }
+
+    // Player transitions to Player.STATE_ENDED if the current index is part of the removed tail.
+    final boolean transitionsToEnded =
+        newPlayerInfo.playbackState != Player.STATE_IDLE
+            && newPlayerInfo.playbackState != Player.STATE_ENDED
+            && fromIndex < toIndex
+            && toIndex == oldTimeline.getWindowCount()
+            && oldMediaItemIndex >= fromIndex;
+    if (transitionsToEnded) {
+      newPlayerInfo =
+          newPlayerInfo.copyWithPlaybackState(Player.STATE_ENDED, /* playerError= */ null);
+    }
+
+    return newPlayerInfo;
   }
 
   @Override
@@ -1176,9 +1180,7 @@ import org.checkerframework.checker.nullness.qual.NonNull;
 
   @Override
   public int getCurrentMediaItemIndex() {
-    return playerInfo.sessionPositionInfo.positionInfo.mediaItemIndex == C.INDEX_UNSET
+    return getCurrentMediaItemIndexInternal(playerInfo);
-        ? 0
-        : playerInfo.sessionPositionInfo.positionInfo.mediaItemIndex;
   }
 
   // TODO(b/184479406): Get the index directly from Player rather than Timeline.
@@ -1773,7 +1775,7 @@ import org.checkerframework.checker.nullness.qual.NonNull;
     return null;
   }
 
-  private Timeline createMaskingTimeline(List<Window> windows, List<Period> periods) {
+  private static Timeline createMaskingTimeline(List<Window> windows, List<Period> periods) {
     return new RemotableTimeline(
         new ImmutableList.Builder<Window>().addAll(windows).build(),
         new ImmutableList.Builder<Period>().addAll(periods).build(),
@@ -2751,7 +2753,7 @@ import org.checkerframework.checker.nullness.qual.NonNull;
   }
 
   @Nullable
-  private PeriodInfo getPeriodInfo(
+  private static PeriodInfo getPeriodInfo(
       Timeline timeline, Window window, Period period, int windowIndex, long windowPositionUs) {
     checkIndex(windowIndex, 0, timeline.getWindowCount());
     timeline.getWindow(windowIndex, window);
@@ -2773,7 +2775,13 @@ import org.checkerframework.checker.nullness.qual.NonNull;
     return new PeriodInfo(periodIndex, periodPositionUs);
   }
 
-  private PlayerInfo maskTimelineAndPositionInfo(
+  private static int getCurrentMediaItemIndexInternal(PlayerInfo playerInfo) {
+    return playerInfo.sessionPositionInfo.positionInfo.mediaItemIndex == C.INDEX_UNSET
+        ? 0
+        : playerInfo.sessionPositionInfo.positionInfo.mediaItemIndex;
+  }
+
+  private static PlayerInfo maskTimelineAndPositionInfo(
       PlayerInfo playerInfo,
       Timeline timeline,
       int newMediaItemIndex,
@@ -2808,7 +2816,7 @@ import org.checkerframework.checker.nullness.qual.NonNull;
         discontinuityReason);
   }
 
-  private PlayerInfo maskTimelineAndPositionInfo(
+  private static PlayerInfo maskTimelineAndPositionInfo(
       PlayerInfo playerInfo,
       Timeline timeline,
       PositionInfo newPositionInfo,
@@ -2853,14 +2861,15 @@ import org.checkerframework.checker.nullness.qual.NonNull;
     currentPositionMs = estimatedPositionMs;
   }
 
-  private Period getPeriodWithNewWindowIndex(Timeline timeline, int periodIndex, int windowIndex) {
+  private static Period getPeriodWithNewWindowIndex(
+      Timeline timeline, int periodIndex, int windowIndex) {
     Period period = new Period();
     timeline.getPeriod(periodIndex, period);
     period.windowIndex = windowIndex;
     return period;
   }
 
-  private int getNewPeriodIndexWithoutRemovedPeriods(
+  private static int getNewPeriodIndexWithoutRemovedPeriods(
       Timeline timeline, int oldPeriodIndex, int fromIndex, int toIndex) {
     if (oldPeriodIndex == C.INDEX_UNSET) {
       return oldPeriodIndex;
@@ -2906,7 +2915,7 @@ import org.checkerframework.checker.nullness.qual.NonNull;
             /* isPlaceholder= */ true);
   }
 
-  private void rebuildPeriods(
+  private static void rebuildPeriods(
       Timeline oldTimeline, List<Window> newWindows, List<Period> newPeriods) {
     for (int i = 0; i < newWindows.size(); i++) {
       Window window = newWindows.get(i);