Fix PlaybackStatsListener behavior when not keeping history

issue:#7160
PiperOrigin-RevId: 303747338

RELEASENOTES.md

@@ -25,6 +25,8 @@
 * UI: Add an option to set whether to use the orientation sensor for rotation
   in spherical playbacks
   ([#6761](https://github.com/google/ExoPlayer/issues/6761)).
+* Analytics: Fix `PlaybackStatsListener` behavior when not keeping history
+  ([#7160](https://github.com/google/ExoPlayer/issues/7160)).
 * FFmpeg extension: Add support for x86_64.
 * Opus extension: Fix parsing of negative gain values
   ([#7046](https://github.com/google/ExoPlayer/issues/7046)).

library/core/src/main/java/com/google/android/exoplayer2/analytics/PlaybackStatsListener.java

@@ -50,7 +50,7 @@ import org.checkerframework.checker.nullness.compatqual.NullableType;
  * <p>For accurate measurements, the listener should be added to the player before loading media,
  * i.e., {@link Player#getPlaybackState()} should be {@link Player#STATE_IDLE}.
  *
- * <p>Playback stats are gathered separately for all playback session, i.e. each window in the
+ * <p>Playback stats are gathered separately for each playback session, i.e. each window in the
  * {@link Timeline} and each single ad.
  */
 public final class PlaybackStatsListener
@@ -931,6 +931,9 @@ public final class PlaybackStatsListener
     }
 
     private void maybeUpdateMediaTimeHistory(long realtimeMs, long mediaTimeMs) {
+      if (!keepHistory) {
+        return;
+      }
       if (currentPlaybackState != PlaybackStats.PLAYBACK_STATE_PLAYING) {
         if (mediaTimeMs == C.TIME_UNSET) {
           return;

library/core/src/test/java/com/google/android/exoplayer2/analytics/PlaybackStatsListenerTest.java

@@ -0,0 +1,74 @@
+/*
+ * Copyright 2020 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package com.google.android.exoplayer2.analytics;
+
+import static com.google.common.truth.Truth.assertThat;
+
+import androidx.annotation.Nullable;
+import androidx.test.ext.junit.runners.AndroidJUnit4;
+import com.google.android.exoplayer2.Player;
+import com.google.android.exoplayer2.Timeline;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+
+/** Unit test for {@link PlaybackStatsListener}. */
+@RunWith(AndroidJUnit4.class)
+public final class PlaybackStatsListenerTest {
+
+  private static final AnalyticsListener.EventTime TEST_EVENT_TIME =
+      new AnalyticsListener.EventTime(
+          /* realtimeMs= */ 500,
+          Timeline.EMPTY,
+          /* windowIndex= */ 0,
+          /* mediaPeriodId= */ null,
+          /* eventPlaybackPositionMs= */ 0,
+          /* currentPlaybackPositionMs= */ 0,
+          /* totalBufferedDurationMs= */ 0);
+
+  @Test
+  public void playback_withKeepHistory_updatesStats() {
+    PlaybackStatsListener playbackStatsListener =
+        new PlaybackStatsListener(/* keepHistory= */ true, /* callback= */ null);
+
+    playbackStatsListener.onPlayerStateChanged(
+        TEST_EVENT_TIME, /* playWhenReady= */ true, Player.STATE_BUFFERING);
+    playbackStatsListener.onPlayerStateChanged(
+        TEST_EVENT_TIME, /* playWhenReady= */ true, Player.STATE_READY);
+    playbackStatsListener.onPlayerStateChanged(
+        TEST_EVENT_TIME, /* playWhenReady= */ true, Player.STATE_ENDED);
+
+    @Nullable PlaybackStats playbackStats = playbackStatsListener.getPlaybackStats();
+    assertThat(playbackStats).isNotNull();
+    assertThat(playbackStats.endedCount).isEqualTo(1);
+  }
+
+  @Test
+  public void playback_withoutKeepHistory_updatesStats() {
+    PlaybackStatsListener playbackStatsListener =
+        new PlaybackStatsListener(/* keepHistory= */ false, /* callback= */ null);
+
+    playbackStatsListener.onPlayerStateChanged(
+        TEST_EVENT_TIME, /* playWhenReady= */ true, Player.STATE_BUFFERING);
+    playbackStatsListener.onPlayerStateChanged(
+        TEST_EVENT_TIME, /* playWhenReady= */ true, Player.STATE_READY);
+    playbackStatsListener.onPlayerStateChanged(
+        TEST_EVENT_TIME, /* playWhenReady= */ true, Player.STATE_ENDED);
+
+    @Nullable PlaybackStats playbackStats = playbackStatsListener.getPlaybackStats();
+    assertThat(playbackStats).isNotNull();
+    assertThat(playbackStats.endedCount).isEqualTo(1);
+  }
+}