Use Clock to create Handler for delivering messages.

This ensures the message devilery is governed by the clock.

Also replace setting a Handler with a Looper to facilititate this
change.

PiperOrigin-RevId: 353019729

RELEASENOTES.md

@@ -138,6 +138,7 @@
         ([#8430](https://github.com/google/ExoPlayer/issues/8430)).
     *   Remove `setVideoDecoderOutputBufferRenderer` from Player API. Use
         `setVideoSurfaceView` and `clearVideoSurfaceView` instead.
+    *   Replace `PlayerMessage.setHandler` with `PlayerMessage.setLooper`.
 *   Extractors:
     *   Populate codecs string for H.264/AVC in MP4, Matroska and FLV streams to
         allow decoder capability checks based on codec profile/level

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

@@ -456,6 +456,9 @@ public interface ExoPlayer extends Player {
   /** Returns the {@link Looper} associated with the playback thread. */
   Looper getPlaybackLooper();
 
+  /** Returns the {@link Clock} used for playback. */
+  Clock getClock();
+
   /** @deprecated Use {@link #prepare()} instead. */
   @Deprecated
   void retry();

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

@@ -70,7 +70,6 @@ import java.util.List;
   private final Handler playbackInfoUpdateHandler;
   private final ExoPlayerImplInternal.PlaybackInfoUpdateListener playbackInfoUpdateListener;
   private final ExoPlayerImplInternal internalPlayer;
-  private final Handler internalPlayerHandler;
   private final ListenerSet<Player.EventListener, Player.Events> listeners;
   private final Timeline.Period period;
   private final List<MediaSourceHolderSnapshot> mediaSourceHolderSnapshots;
@@ -79,6 +78,7 @@ import java.util.List;
   @Nullable private final AnalyticsCollector analyticsCollector;
   private final Looper applicationLooper;
   private final BandwidthMeter bandwidthMeter;
+  private final Clock clock;
 
   @RepeatMode private int repeatMode;
   private boolean shuffleModeEnabled;
@@ -149,6 +149,7 @@ import java.util.List;
     this.seekParameters = seekParameters;
     this.pauseAtEndOfMediaItems = pauseAtEndOfMediaItems;
     this.applicationLooper = applicationLooper;
+    this.clock = clock;
     repeatMode = Player.REPEAT_MODE_OFF;
     Player playerForListeners = wrappingPlayer != null ? wrappingPlayer : this;
     listeners =
@@ -193,7 +194,6 @@ import java.util.List;
             applicationLooper,
             clock,
             playbackInfoUpdateListener);
-    internalPlayerHandler = new Handler(internalPlayer.getPlaybackLooper());
   }
 
   /**
@@ -261,6 +261,11 @@ import java.util.List;
   }
 
   @Override
+  public Clock getClock() {
+    return clock;
+  }
+
+  @Override
   public void addListener(Player.EventListener listener) {
     listeners.add(listener);
   }
@@ -755,7 +760,8 @@ import java.util.List;
         target,
         playbackInfo.timeline,
         getCurrentWindowIndex(),
-        internalPlayerHandler);
+        clock,
+        internalPlayer.getPlaybackLooper());
   }
 
   @Override

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

@@ -1468,7 +1468,7 @@ import java.util.concurrent.atomic.AtomicBoolean;
   }
 
   private void sendMessageToTarget(PlayerMessage message) throws ExoPlaybackException {
-    if (message.getHandler().getLooper() == playbackLooper) {
+    if (message.getLooper() == playbackLooper) {
       deliverMessage(message);
       if (playbackInfo.playbackState == Player.STATE_READY
           || playbackInfo.playbackState == Player.STATE_BUFFERING) {
@@ -1481,21 +1481,23 @@ import java.util.concurrent.atomic.AtomicBoolean;
   }
 
   private void sendMessageToTargetThread(final PlayerMessage message) {
-    Handler handler = message.getHandler();
-    if (!handler.getLooper().getThread().isAlive()) {
+    Looper looper = message.getLooper();
+    if (!looper.getThread().isAlive()) {
       Log.w("TAG", "Trying to send message on a dead thread.");
       message.markAsProcessed(/* isDelivered= */ false);
       return;
     }
-    handler.post(
-        () -> {
-          try {
-            deliverMessage(message);
-          } catch (ExoPlaybackException e) {
-            Log.e(TAG, "Unexpected error delivering message on external thread.", e);
-            throw new RuntimeException(e);
-          }
-        });
+    clock
+        .createHandler(looper, /* callback= */ null)
+        .post(
+            () -> {
+              try {
+                deliverMessage(message);
+              } catch (ExoPlaybackException e) {
+                Log.e(TAG, "Unexpected error delivering message on external thread.", e);
+                throw new RuntimeException(e);
+              }
+            });
   }
 
   private void deliverMessage(PlayerMessage message) throws ExoPlaybackException {

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

@@ -16,8 +16,8 @@
 package com.google.android.exoplayer2;
 
 import android.os.Handler;
+import android.os.Looper;
 import androidx.annotation.Nullable;
-import androidx.annotation.VisibleForTesting;
 import com.google.android.exoplayer2.util.Assertions;
 import com.google.android.exoplayer2.util.Clock;
 import java.util.concurrent.TimeoutException;
@@ -55,11 +55,12 @@ public final class PlayerMessage {
 
   private final Target target;
   private final Sender sender;
+  private final Clock clock;
   private final Timeline timeline;
 
   private int type;
   @Nullable private Object payload;
-  private Handler handler;
+  private Looper looper;
   private int windowIndex;
   private long positionMs;
   private boolean deleteAfterDelivery;
@@ -77,7 +78,8 @@ public final class PlayerMessage {
    *     set to {@link Timeline#EMPTY}, any position can be specified.
    * @param defaultWindowIndex The default window index in the {@code timeline} when no other window
    *     index is specified.
-   * @param defaultHandler The default handler to send the message on when no other handler is
+   * @param clock The {@link Clock}.
+   * @param defaultLooper The default {@link Looper} to send the message on when no other looper is
    *     specified.
    */
   public PlayerMessage(
@@ -85,11 +87,13 @@ public final class PlayerMessage {
       Target target,
       Timeline timeline,
       int defaultWindowIndex,
-      Handler defaultHandler) {
+      Clock clock,
+      Looper defaultLooper) {
     this.sender = sender;
     this.target = target;
     this.timeline = timeline;
-    this.handler = defaultHandler;
+    this.looper = defaultLooper;
+    this.clock = clock;
     this.windowIndex = defaultWindowIndex;
     this.positionMs = C.TIME_UNSET;
     this.deleteAfterDelivery = true;
@@ -142,22 +146,28 @@ public final class PlayerMessage {
     return payload;
   }
 
+  /** @deprecated Use {@link #setLooper(Looper)} instead. */
+  @Deprecated
+  public PlayerMessage setHandler(Handler handler) {
+    return setLooper(handler.getLooper());
+  }
+
   /**
-   * Sets the handler the message is delivered on.
+   * Sets the {@link Looper} the message is delivered on.
    *
-   * @param handler A {@link Handler}.
+   * @param looper A {@link Looper}.
    * @return This message.
    * @throws IllegalStateException If {@link #send()} has already been called.
    */
-  public PlayerMessage setHandler(Handler handler) {
+  public PlayerMessage setLooper(Looper looper) {
     Assertions.checkState(!isSent);
-    this.handler = handler;
+    this.looper = looper;
     return this;
   }
 
-  /** Returns the handler the message is delivered on. */
-  public Handler getHandler() {
-    return handler;
+  /** Returns the {@link Looper} the message is delivered on. */
+  public Looper getLooper() {
+    return looper;
   }
 
   /**
@@ -287,19 +297,19 @@ public final class PlayerMessage {
    * Blocks until after the message has been delivered or the player is no longer able to deliver
    * the message.
    *
-   * <p>Note that this method can't be called if the current thread is the same thread used by the
-   * message handler set with {@link #setHandler(Handler)} as it would cause a deadlock.
+   * <p>Note that this method must not be called if the current thread is the same thread used by
+   * the message {@link #getLooper() looper} as it would cause a deadlock.
    *
    * @return Whether the message was delivered successfully.
    * @throws IllegalStateException If this method is called before {@link #send()}.
    * @throws IllegalStateException If this method is called on the same thread used by the message
-   *     handler set with {@link #setHandler(Handler)}.
+   *     {@link #getLooper() looper}.
    * @throws InterruptedException If the current thread is interrupted while waiting for the message
    *     to be delivered.
    */
   public synchronized boolean blockUntilDelivered() throws InterruptedException {
     Assertions.checkState(isSent);
-    Assertions.checkState(handler.getLooper().getThread() != Thread.currentThread());
+    Assertions.checkState(looper.getThread() != Thread.currentThread());
     while (!isProcessed) {
       wait();
     }
@@ -310,14 +320,14 @@ public final class PlayerMessage {
    * Blocks until after the message has been delivered or the player is no longer able to deliver
    * the message or the specified timeout elapsed.
    *
-   * <p>Note that this method can't be called if the current thread is the same thread used by the
-   * message handler set with {@link #setHandler(Handler)} as it would cause a deadlock.
+   * <p>Note that this method must not be called if the current thread is the same thread used by
+   * the message {@link #getLooper() looper} as it would cause a deadlock.
    *
    * @param timeoutMs The timeout in milliseconds.
    * @return Whether the message was delivered successfully.
    * @throws IllegalStateException If this method is called before {@link #send()}.
    * @throws IllegalStateException If this method is called on the same thread used by the message
-   *     handler set with {@link #setHandler(Handler)}.
+   *     {@link #getLooper() looper}.
    * @throws TimeoutException If the {@code timeoutMs} elapsed and this message has not been
    *     delivered and the player is still able to deliver the message.
    * @throws InterruptedException If the current thread is interrupted while waiting for the message
@@ -325,14 +335,8 @@ public final class PlayerMessage {
    */
   public synchronized boolean blockUntilDelivered(long timeoutMs)
       throws InterruptedException, TimeoutException {
-    return blockUntilDelivered(timeoutMs, Clock.DEFAULT);
-  }
-
-  @VisibleForTesting()
-  /* package */ synchronized boolean blockUntilDelivered(long timeoutMs, Clock clock)
-      throws InterruptedException, TimeoutException {
     Assertions.checkState(isSent);
-    Assertions.checkState(handler.getLooper().getThread() != Thread.currentThread());
+    Assertions.checkState(looper.getThread() != Thread.currentThread());
 
     long deadlineMs = clock.elapsedRealtime() + timeoutMs;
     long remainingMs = timeoutMs;
@@ -340,11 +344,9 @@ public final class PlayerMessage {
       wait(remainingMs);
       remainingMs = deadlineMs - clock.elapsedRealtime();
     }
-
     if (!isProcessed) {
       throw new TimeoutException("Message delivery timed out.");
     }
-
     return isDelivered;
   }
 }

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

@@ -1203,6 +1203,11 @@ public class SimpleExoPlayer extends BasePlayer
   }
 
   @Override
+  public Clock getClock() {
+    return player.getClock();
+  }
+
+  @Override
   public void addListener(Player.EventListener listener) {
     // Don't verify application thread. We allow calls to this method from any thread.
     Assertions.checkNotNull(listener);

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

@@ -22,7 +22,6 @@ import static org.mockito.Mockito.verify;
 import static org.mockito.Mockito.when;
 import static org.mockito.MockitoAnnotations.initMocks;
 
-import android.os.Handler;
 import android.os.HandlerThread;
 import androidx.test.ext.junit.runners.AndroidJUnit4;
 import com.google.android.exoplayer2.util.Clock;
@@ -55,9 +54,14 @@ public class PlayerMessageTest {
     PlayerMessage.Target target = (messageType, payload) -> {};
     handlerThread = new HandlerThread("TestHandler");
     handlerThread.start();
-    Handler handler = new Handler(handlerThread.getLooper());
     message =
-        new PlayerMessage(sender, target, Timeline.EMPTY, /* defaultWindowIndex= */ 0, handler);
+        new PlayerMessage(
+            sender,
+            target,
+            Timeline.EMPTY,
+            /* defaultWindowIndex= */ 0,
+            clock,
+            handlerThread.getLooper());
   }
 
   @After
@@ -69,8 +73,7 @@ public class PlayerMessageTest {
   public void blockUntilDelivered_timesOut() throws Exception {
     when(clock.elapsedRealtime()).thenReturn(0L).thenReturn(TIMEOUT_MS * 2);
 
-    assertThrows(
-        TimeoutException.class, () -> message.send().blockUntilDelivered(TIMEOUT_MS, clock));
+    assertThrows(TimeoutException.class, () -> message.send().blockUntilDelivered(TIMEOUT_MS));
 
     // Ensure blockUntilDelivered() entered the blocking loop.
     verify(clock, Mockito.times(2)).elapsedRealtime();
@@ -82,7 +85,7 @@ public class PlayerMessageTest {
 
     message.send().markAsProcessed(/* isDelivered= */ true);
 
-    assertThat(message.blockUntilDelivered(TIMEOUT_MS, clock)).isTrue();
+    assertThat(message.blockUntilDelivered(TIMEOUT_MS)).isTrue();
   }
 
   @Test
@@ -110,7 +113,7 @@ public class PlayerMessageTest {
             });
 
     try {
-      assertThat(message.blockUntilDelivered(TIMEOUT_MS, clock)).isTrue();
+      assertThat(message.blockUntilDelivered(TIMEOUT_MS)).isTrue();
       // Ensure blockUntilDelivered() entered the blocking loop.
       verify(clock, Mockito.atLeast(2)).elapsedRealtime();
       future.get(1, SECONDS);

robolectricutils/src/main/java/com/google/android/exoplayer2/robolectric/TestPlayerRunHelper.java

@@ -18,7 +18,6 @@ package com.google.android.exoplayer2.robolectric;
 
 import static com.google.android.exoplayer2.robolectric.RobolectricUtil.runMainLooperUntil;
 
-import android.os.Handler;
 import android.os.Looper;
 import com.google.android.exoplayer2.ExoPlaybackException;
 import com.google.android.exoplayer2.ExoPlayer;
@@ -297,20 +296,22 @@ public class TestPlayerRunHelper {
   public static void playUntilPosition(ExoPlayer player, int windowIndex, long positionMs)
       throws TimeoutException {
     verifyMainTestThread(player);
-    Handler testHandler = Util.createHandlerForCurrentOrMainLooper();
-
+    Looper applicationLooper = Util.getCurrentOrMainLooper();
     AtomicBoolean messageHandled = new AtomicBoolean(false);
     player
         .createMessage(
             (messageType, payload) -> {
               // Block playback thread until pause command has been sent from test thread.
               ConditionVariable blockPlaybackThreadCondition = new ConditionVariable();
-              testHandler.post(
-                  () -> {
-                    player.pause();
-                    messageHandled.set(true);
-                    blockPlaybackThreadCondition.open();
-                  });
+              player
+                  .getClock()
+                  .createHandler(applicationLooper, /* callback= */ null)
+                  .post(
+                      () -> {
+                        player.pause();
+                        messageHandled.set(true);
+                        blockPlaybackThreadCondition.open();
+                      });
               try {
                 blockPlaybackThreadCondition.block();
               } catch (InterruptedException e) {
@@ -354,7 +355,7 @@ public class TestPlayerRunHelper {
     AtomicBoolean receivedMessageCallback = new AtomicBoolean(false);
     player
         .createMessage((type, data) -> receivedMessageCallback.set(true))
-        .setHandler(Util.createHandlerForCurrentOrMainLooper())
+        .setLooper(Util.getCurrentOrMainLooper())
         .send();
     runMainLooperUntil(receivedMessageCallback::get);
   }

testutils/src/main/java/com/google/android/exoplayer2/testutil/Action.java

@@ -15,7 +15,7 @@
  */
 package com.google.android.exoplayer2.testutil;
 
-import android.os.Handler;
+import android.os.Looper;
 import android.view.Surface;
 import androidx.annotation.Nullable;
 import com.google.android.exoplayer2.C;
@@ -603,7 +603,7 @@ public abstract class Action {
       } else {
         message.setPosition(positionMs);
       }
-      message.setHandler(Util.createHandlerForCurrentOrMainLooper());
+      message.setLooper(Util.getCurrentOrMainLooper());
       message.setDeleteAfterDelivery(deleteAfterDelivery);
       message.send();
     }
@@ -685,18 +685,21 @@ public abstract class Action {
         @Nullable Surface surface,
         HandlerWrapper handler,
         @Nullable ActionNode nextAction) {
-      Handler testThreadHandler = Util.createHandlerForCurrentOrMainLooper();
       // Schedule a message on the playback thread to ensure the player is paused immediately.
+      Looper applicationLooper = Util.getCurrentOrMainLooper();
       player
           .createMessage(
               (messageType, payload) -> {
                 // Block playback thread until pause command has been sent from test thread.
                 ConditionVariable blockPlaybackThreadCondition = new ConditionVariable();
-                testThreadHandler.post(
-                    () -> {
-                      player.pause();
-                      blockPlaybackThreadCondition.open();
-                    });
+                player
+                    .getClock()
+                    .createHandler(applicationLooper, /* callback= */ null)
+                    .post(
+                        () -> {
+                          player.pause();
+                          blockPlaybackThreadCondition.open();
+                        });
                 try {
                   blockPlaybackThreadCondition.block();
                 } catch (InterruptedException e) {
@@ -712,7 +715,7 @@ public abstract class Action {
                 (messageType, payload) ->
                     nextAction.schedule(player, trackSelector, surface, handler))
             .setPosition(windowIndex, positionMs)
-            .setHandler(testThreadHandler)
+            .setLooper(applicationLooper)
             .send();
       }
       player.play();
@@ -1049,7 +1052,7 @@ public abstract class Action {
       player
           .createMessage(
               (type, data) -> nextAction.schedule(player, trackSelector, surface, handler))
-          .setHandler(Util.createHandlerForCurrentOrMainLooper())
+          .setLooper(Util.getCurrentOrMainLooper())
           .send();
     }
 

testutils/src/main/java/com/google/android/exoplayer2/testutil/StubExoPlayer.java

@@ -32,6 +32,7 @@ import com.google.android.exoplayer2.source.ShuffleOrder;
 import com.google.android.exoplayer2.source.TrackGroupArray;
 import com.google.android.exoplayer2.trackselection.TrackSelectionArray;
 import com.google.android.exoplayer2.trackselection.TrackSelector;
+import com.google.android.exoplayer2.util.Clock;
 import java.util.List;
 
 /**
@@ -76,6 +77,11 @@ public abstract class StubExoPlayer extends BasePlayer implements ExoPlayer {
   }
 
   @Override
+  public Clock getClock() {
+    throw new UnsupportedOperationException();
+  }
+
+  @Override
   public void addListener(Player.EventListener listener) {
     throw new UnsupportedOperationException();
   }