From cd91ae4053b17952decae2b01e5dd95ce47247ba Mon Sep 17 00:00:00 2001
From: christosts <christosts@google.com>
Date: Mon, 13 Sep 2021 12:59:22 +0100
Subject: [PATCH] PlaybackStatsListener: add check when adding guessed times

This is was reported in #9257 where the PlaybackStatsListener may try to
access an emtpy ArrayList.

Issue: #9257

#minor-release
#exofixit

PiperOrigin-RevId: 396329373
---
 .../exoplayer2/analytics/PlaybackStatsListener.java    | 10 ++++++----
 1 file changed, 6 insertions(+), 4 deletions(-)

diff --git a/library/core/src/main/java/com/google/android/exoplayer2/analytics/PlaybackStatsListener.java b/library/core/src/main/java/com/google/android/exoplayer2/analytics/PlaybackStatsListener.java
index fd349ea60c..e061066788 100644
--- a/library/core/src/main/java/com/google/android/exoplayer2/analytics/PlaybackStatsListener.java
+++ b/library/core/src/main/java/com/google/android/exoplayer2/analytics/PlaybackStatsListener.java
@@ -769,10 +769,12 @@ public final class PlaybackStatsListener
           }
         }
       }
-      mediaTimeHistory.add(
-          mediaTimeMs == C.TIME_UNSET
-              ? guessMediaTimeBasedOnElapsedRealtime(realtimeMs)
-              : new long[] {realtimeMs, mediaTimeMs});
+
+      if (mediaTimeMs != C.TIME_UNSET) {
+        mediaTimeHistory.add(new long[] {realtimeMs, mediaTimeMs});
+      } else if (!mediaTimeHistory.isEmpty()) {
+        mediaTimeHistory.add(guessMediaTimeBasedOnElapsedRealtime(realtimeMs));
+      }
     }
 
     private long[] guessMediaTimeBasedOnElapsedRealtime(long realtimeMs) {