Ensure position reset keep window sequence number.

We currently keep the sequence number if we don't reset the position. However,
the sequence number should be kept if we don't reset the state. Otherwise
re-prepare with position reset is counted as new playback although it's still
the same.

PiperOrigin-RevId: 261644924

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

@@ -647,7 +647,7 @@ import java.util.concurrent.CopyOnWriteArrayList;
     resetPosition = resetPosition || resetState;
     resetPosition = resetPosition || resetState;
     MediaPeriodId mediaPeriodId =
     MediaPeriodId mediaPeriodId =
         resetPosition
         resetPosition
-            ? playbackInfo.getDummyFirstMediaPeriodId(shuffleModeEnabled, window)
+            ? playbackInfo.getDummyFirstMediaPeriodId(shuffleModeEnabled, window, period)
             : playbackInfo.periodId;
             : playbackInfo.periodId;
     long startPositionUs = resetPosition ? 0 : playbackInfo.positionUs;
     long startPositionUs = resetPosition ? 0 : playbackInfo.positionUs;
     long contentPositionUs = resetPosition ? C.TIME_UNSET : playbackInfo.contentPositionUs;
     long contentPositionUs = resetPosition ? C.TIME_UNSET : playbackInfo.contentPositionUs;

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

@@ -646,7 +646,7 @@ import java.util.concurrent.atomic.AtomicBoolean;
     if (resolvedSeekPosition == null) {
     if (resolvedSeekPosition == null) {
       // The seek position was valid for the timeline that it was performed into, but the
       // The seek position was valid for the timeline that it was performed into, but the
       // timeline has changed or is not ready and a suitable seek position could not be resolved.
       // timeline has changed or is not ready and a suitable seek position could not be resolved.
-      periodId = playbackInfo.getDummyFirstMediaPeriodId(shuffleModeEnabled, window);
+      periodId = playbackInfo.getDummyFirstMediaPeriodId(shuffleModeEnabled, window, period);
       periodPositionUs = C.TIME_UNSET;
       periodPositionUs = C.TIME_UNSET;
       contentPositionUs = C.TIME_UNSET;
       contentPositionUs = C.TIME_UNSET;
       seekPositionAdjusted = true;
       seekPositionAdjusted = true;
@@ -884,7 +884,7 @@ import java.util.concurrent.atomic.AtomicBoolean;
       }
       }
     }
     }
 
 
-    queue.clear(/* keepFrontPeriodUid= */ !resetPosition);
+    queue.clear(/* keepFrontPeriodUid= */ !resetState);
     setIsLoading(false);
     setIsLoading(false);
     if (resetState) {
     if (resetState) {
       queue.setTimeline(Timeline.EMPTY);
       queue.setTimeline(Timeline.EMPTY);
@@ -896,7 +896,7 @@ import java.util.concurrent.atomic.AtomicBoolean;
     }
     }
     MediaPeriodId mediaPeriodId =
     MediaPeriodId mediaPeriodId =
         resetPosition
         resetPosition
-            ? playbackInfo.getDummyFirstMediaPeriodId(shuffleModeEnabled, window)
+            ? playbackInfo.getDummyFirstMediaPeriodId(shuffleModeEnabled, window, period)
             : playbackInfo.periodId;
             : playbackInfo.periodId;
     // Set the start position to TIME_UNSET so that a subsequent seek to 0 isn't ignored.
     // Set the start position to TIME_UNSET so that a subsequent seek to 0 isn't ignored.
     long startPositionUs = resetPosition ? C.TIME_UNSET : playbackInfo.positionUs;
     long startPositionUs = resetPosition ? C.TIME_UNSET : playbackInfo.positionUs;

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

@@ -150,17 +150,26 @@ import com.google.android.exoplayer2.trackselection.TrackSelectorResult;
    *
    *
    * @param shuffleModeEnabled Whether shuffle mode is enabled.
    * @param shuffleModeEnabled Whether shuffle mode is enabled.
    * @param window A writable {@link Timeline.Window}.
    * @param window A writable {@link Timeline.Window}.
+   * @param period A writable {@link Timeline.Period}.
    * @return A dummy media period id for the first-to-be-played period of the current timeline.
    * @return A dummy media period id for the first-to-be-played period of the current timeline.
    */
    */
   public MediaPeriodId getDummyFirstMediaPeriodId(
   public MediaPeriodId getDummyFirstMediaPeriodId(
-      boolean shuffleModeEnabled, Timeline.Window window) {
+      boolean shuffleModeEnabled, Timeline.Window window, Timeline.Period period) {
     if (timeline.isEmpty()) {
     if (timeline.isEmpty()) {
       return DUMMY_MEDIA_PERIOD_ID;
       return DUMMY_MEDIA_PERIOD_ID;
     }
     }
-    int firstPeriodIndex =
-        timeline.getWindow(timeline.getFirstWindowIndex(shuffleModeEnabled), window)
-            .firstPeriodIndex;
-    return new MediaPeriodId(timeline.getUidOfPeriod(firstPeriodIndex));
+    int firstWindowIndex = timeline.getFirstWindowIndex(shuffleModeEnabled);
+    int firstPeriodIndex = timeline.getWindow(firstWindowIndex, window).firstPeriodIndex;
+    int currentPeriodIndex = timeline.getIndexOfPeriod(periodId.periodUid);
+    long windowSequenceNumber = C.INDEX_UNSET;
+    if (currentPeriodIndex != C.INDEX_UNSET) {
+      int currentWindowIndex = timeline.getPeriod(currentPeriodIndex, period).windowIndex;
+      if (firstWindowIndex == currentWindowIndex) {
+        // Keep window sequence number if the new position is still in the same window.
+        windowSequenceNumber = periodId.windowSequenceNumber;
+      }
+    }
+    return new MediaPeriodId(timeline.getUidOfPeriod(firstPeriodIndex), windowSequenceNumber);
   }
   }
 
 
   /**
   /**

library/core/src/test/java/com/google/android/exoplayer2/ExoPlayerTest.java

@@ -28,6 +28,7 @@ import androidx.test.ext.junit.runners.AndroidJUnit4;
 import com.google.android.exoplayer2.Player.DiscontinuityReason;
 import com.google.android.exoplayer2.Player.DiscontinuityReason;
 import com.google.android.exoplayer2.Player.EventListener;
 import com.google.android.exoplayer2.Player.EventListener;
 import com.google.android.exoplayer2.Timeline.Window;
 import com.google.android.exoplayer2.Timeline.Window;
+import com.google.android.exoplayer2.analytics.AnalyticsListener;
 import com.google.android.exoplayer2.source.ClippingMediaSource;
 import com.google.android.exoplayer2.source.ClippingMediaSource;
 import com.google.android.exoplayer2.source.ConcatenatingMediaSource;
 import com.google.android.exoplayer2.source.ConcatenatingMediaSource;
 import com.google.android.exoplayer2.source.MediaSource;
 import com.google.android.exoplayer2.source.MediaSource;
@@ -59,6 +60,7 @@ import java.io.IOException;
 import java.util.ArrayList;
 import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.Arrays;
 import java.util.Collections;
 import java.util.Collections;
+import java.util.HashSet;
 import java.util.List;
 import java.util.List;
 import java.util.concurrent.CountDownLatch;
 import java.util.concurrent.CountDownLatch;
 import java.util.concurrent.atomic.AtomicInteger;
 import java.util.concurrent.atomic.AtomicInteger;
@@ -1435,6 +1437,46 @@ public final class ExoPlayerTest {
   }
   }
 
 
   @Test
   @Test
+  public void playbackErrorAndReprepareWithPositionResetKeepsWindowSequenceNumber()
+      throws Exception {
+    FakeMediaSource mediaSource = new FakeMediaSource(new FakeTimeline(/* windowCount= */ 1));
+    ActionSchedule actionSchedule =
+        new ActionSchedule.Builder("playbackErrorWithResetKeepsWindowSequenceNumber")
+            .pause()
+            .waitForPlaybackState(Player.STATE_READY)
+            .throwPlaybackException(ExoPlaybackException.createForSource(new IOException()))
+            .waitForPlaybackState(Player.STATE_IDLE)
+            .prepareSource(mediaSource, /* resetPosition= */ true, /* resetState= */ false)
+            .waitForPlaybackState(Player.STATE_READY)
+            .play()
+            .build();
+    HashSet<Long> reportedWindowSequenceNumbers = new HashSet<>();
+    AnalyticsListener listener =
+        new AnalyticsListener() {
+          @Override
+          public void onPlayerStateChanged(
+              EventTime eventTime, boolean playWhenReady, int playbackState) {
+            if (eventTime.mediaPeriodId != null) {
+              reportedWindowSequenceNumbers.add(eventTime.mediaPeriodId.windowSequenceNumber);
+            }
+          }
+        };
+    ExoPlayerTestRunner testRunner =
+        new ExoPlayerTestRunner.Builder()
+            .setMediaSource(mediaSource)
+            .setActionSchedule(actionSchedule)
+            .setAnalyticsListener(listener)
+            .build(context);
+    try {
+      testRunner.start().blockUntilActionScheduleFinished(TIMEOUT_MS).blockUntilEnded(TIMEOUT_MS);
+      fail();
+    } catch (ExoPlaybackException e) {
+      // Expected exception.
+    }
+    assertThat(reportedWindowSequenceNumbers).hasSize(1);
+  }
+
+  @Test
   public void testPlaybackErrorTwiceStillKeepsTimeline() throws Exception {
   public void testPlaybackErrorTwiceStillKeepsTimeline() throws Exception {
     final Timeline timeline = new FakeTimeline(/* windowCount= */ 1);
     final Timeline timeline = new FakeTimeline(/* windowCount= */ 1);
     final FakeMediaSource mediaSource2 = new FakeMediaSource(/* timeline= */ null);
     final FakeMediaSource mediaSource2 = new FakeMediaSource(/* timeline= */ null);