From f18d81f8a88833d1410344bdb70c66ff3f16cb3c Mon Sep 17 00:00:00 2001
From: tonihei <tonihei@google.com>
Date: Wed, 9 Dec 2020 16:07:44 +0000
Subject: [PATCH] Ensure onEvents is called when listener is removed.

When a listener is removed or released we may not have called
onEvents for events that happened before this point. To ensure
listeners don't miss events we need to trigger a final onEvents
with all events we have happened so far (if any).

PiperOrigin-RevId: 346553030
---
 .../android/exoplayer2/util/ListenerSet.java     | 16 +++++++++++-----
 .../android/exoplayer2/util/ListenerSetTest.java |  4 +++-
 2 files changed, 14 insertions(+), 6 deletions(-)

diff --git a/library/core/src/main/java/com/google/android/exoplayer2/util/ListenerSet.java b/library/core/src/main/java/com/google/android/exoplayer2/util/ListenerSet.java
index f98ff33f6d..24bf624338 100644
--- a/library/core/src/main/java/com/google/android/exoplayer2/util/ListenerSet.java
+++ b/library/core/src/main/java/com/google/android/exoplayer2/util/ListenerSet.java
@@ -156,7 +156,7 @@ public final class ListenerSet<T, E extends MutableFlags> {
   public void remove(T listener) {
     for (ListenerHolder<T, E> listenerHolder : listeners) {
       if (listenerHolder.listener.equals(listener)) {
-        listenerHolder.release();
+        listenerHolder.release(iterationFinishedEvent);
         listeners.remove(listenerHolder);
       }
     }
@@ -221,7 +221,7 @@ public final class ListenerSet<T, E extends MutableFlags> {
    */
   public void release() {
     for (ListenerHolder<T, E> listenerHolder : listeners) {
-      listenerHolder.release();
+      listenerHolder.release(iterationFinishedEvent);
     }
     listeners.clear();
     released = true;
@@ -245,6 +245,7 @@ public final class ListenerSet<T, E extends MutableFlags> {
     @Nonnull public final T listener;
 
     private E eventsFlags;
+    private boolean needsIterationFinishedEvent;
     private boolean released;
 
     public ListenerHolder(@Nonnull T listener, Supplier<E> eventFlagSupplier) {
@@ -252,26 +253,31 @@ public final class ListenerSet<T, E extends MutableFlags> {
       this.eventsFlags = eventFlagSupplier.get();
     }
 
-    public void release() {
+    public void release(IterationFinishedEvent<T, E> event) {
       released = true;
+      if (needsIterationFinishedEvent) {
+        event.invoke(listener, eventsFlags);
+      }
     }
 
     public void invoke(int eventFlag, Event<T> event) {
       if (!released) {
-        event.invoke(listener);
         if (eventFlag != C.INDEX_UNSET) {
           eventsFlags.add(eventFlag);
         }
+        needsIterationFinishedEvent = true;
+        event.invoke(listener);
       }
     }
 
     public void iterationFinished(
         Supplier<E> eventFlagSupplier, IterationFinishedEvent<T, E> event) {
-      if (!released) {
+      if (!released && needsIterationFinishedEvent) {
         // Reset flags before invoking the listener to ensure we keep all new flags that are set by
         // recursive events triggered from this callback.
         E flagToNotify = eventsFlags;
         eventsFlags = eventFlagSupplier.get();
+        needsIterationFinishedEvent = false;
         event.invoke(listener, flagToNotify);
       }
     }
diff --git a/library/core/src/test/java/com/google/android/exoplayer2/util/ListenerSetTest.java b/library/core/src/test/java/com/google/android/exoplayer2/util/ListenerSetTest.java
index 604e0d5a0a..19ffd24899 100644
--- a/library/core/src/test/java/com/google/android/exoplayer2/util/ListenerSetTest.java
+++ b/library/core/src/test/java/com/google/android/exoplayer2/util/ListenerSetTest.java
@@ -297,10 +297,11 @@ public class ListenerSetTest {
     // Listener2 shouldn't even get this event as it's removed before the event can be invoked.
     listenerSet.sendEvent(EVENT_ID_1, TestListener::callback1);
     listenerSet.remove(listener1);
-    listenerSet.sendEvent(EVENT_ID_1, TestListener::callback1);
+    listenerSet.sendEvent(EVENT_ID_2, TestListener::callback2);
     ShadowLooper.runMainLooperToNextTask();
 
     verify(listener1).callback1();
+    verify(listener1).iterationFinished(Flags.create(EVENT_ID_1));
     verifyNoMoreInteractions(listener1, listener2);
   }
 
@@ -348,6 +349,7 @@ public class ListenerSetTest {
     ShadowLooper.runMainLooperToNextTask();
 
     verify(listener1).callback1();
+    verify(listener1).iterationFinished(Flags.create(EVENT_ID_1));
     verifyNoMoreInteractions(listener1, listener2);
   }