Clean-up of player message handling.

Some readability fixes for PlayerMessage and the handling in
ExoPlayerImplInternal.

-------------
Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=180544294

extensions/vp9/src/androidTest/java/com/google/android/exoplayer2/ext/vp9/VpxPlaybackTest.java

@@ -122,7 +122,7 @@ public class VpxPlaybackTest extends InstrumentationTestCase {
       player
           .createMessage(videoRenderer)
           .setType(LibvpxVideoRenderer.MSG_SET_OUTPUT_BUFFER_RENDERER)
-          .setMessage(new VpxVideoSurfaceView(context))
+          .setPayload(new VpxVideoSurfaceView(context))
           .send();
       player.prepare(mediaSource);
       player.setPlayWhenReady(true);

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

@@ -217,7 +217,7 @@ public interface ExoPlayer extends Player {
   /**
    * Creates a message that can be sent to a {@link PlayerMessage.Target}. By default, the message
    * will be delivered immediately without blocking on the playback thread. The default {@link
-   * PlayerMessage#getType()} is 0 and the default {@link PlayerMessage#getMessage()} is null. If a
+   * PlayerMessage#getType()} is 0 and the default {@link PlayerMessage#getPayload()} is null. If a
    * position is specified with {@link PlayerMessage#setPosition(long)}, the message will be
    * delivered at this position in the current window defined by {@link #getCurrentWindowIndex()}.
    * Alternatively, the message can be sent at a specific window using {@link

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

@@ -336,7 +336,7 @@ import java.util.concurrent.CopyOnWriteArraySet;
   @Override
   public void sendMessages(ExoPlayerMessage... messages) {
     for (ExoPlayerMessage message : messages) {
-      createMessage(message.target).setType(message.messageType).setMessage(message.message).send();
+      createMessage(message.target).setType(message.messageType).setPayload(message.message).send();
     }
   }
 
@@ -357,7 +357,7 @@ import java.util.concurrent.CopyOnWriteArraySet;
       playerMessages.add(
           createMessage(message.target)
               .setType(message.messageType)
-              .setMessage(message.message)
+              .setPayload(message.message)
               .send());
     }
     boolean wasInterrupted = false;

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

@@ -79,6 +79,7 @@ import java.util.Collections;
   private static final int MSG_CUSTOM = 12;
   private static final int MSG_SET_REPEAT_MODE = 13;
   private static final int MSG_SET_SHUFFLE_ENABLED = 14;
+  private static final int MSG_SEND_MESSAGE_TO_TARGET = 15;
 
   private static final int PREPARING_SOURCE_INTERVAL_MS = 10;
   private static final int RENDERING_INTERVAL_MS = 10;
@@ -223,14 +224,13 @@ import java.util.Collections;
   }
 
   @Override
-  public synchronized void sendMessage(
-      PlayerMessage message, PlayerMessage.Sender.Listener listener) {
+  public synchronized void sendMessage(PlayerMessage message) {
     if (released) {
       Log.w(TAG, "Ignoring messages sent after release.");
-      listener.onMessageDeleted();
+      message.markAsProcessed(/* isDelivered= */ false);
       return;
     }
-    handler.obtainMessage(MSG_CUSTOM, new CustomMessageInfo(message, listener)).sendToTarget();
+    handler.obtainMessage(MSG_CUSTOM, message).sendToTarget();
   }
 
   public synchronized void release() {
@@ -338,7 +338,10 @@ import java.util.Collections;
           reselectTracksInternal();
           break;
         case MSG_CUSTOM:
-          sendMessageInternal((CustomMessageInfo) msg.obj);
+          sendMessageInternal((PlayerMessage) msg.obj);
+          break;
+        case MSG_SEND_MESSAGE_TO_TARGET:
+          sendCustomMessageToTargetThread((PlayerMessage) msg.obj);
           break;
         case MSG_RELEASE:
           releaseInternal();
@@ -838,7 +841,7 @@ import java.util.Collections;
     if (resetState) {
       mediaPeriodInfoSequence.setTimeline(null);
       for (CustomMessageInfo customMessageInfo : customMessageInfos) {
-        customMessageInfo.listener.onMessageDeleted();
+        customMessageInfo.message.markAsProcessed(/* isDelivered= */ false);
       }
       customMessageInfos.clear();
       nextCustomMessageInfoIndex = 0;
@@ -862,58 +865,54 @@ import java.util.Collections;
     }
   }
 
-  private void sendMessageInternal(CustomMessageInfo customMessageInfo) {
-    if (customMessageInfo.message.getPositionMs() == C.TIME_UNSET) {
+  private void sendMessageInternal(PlayerMessage message) {
+    if (message.getPositionMs() == C.TIME_UNSET) {
       // If no delivery time is specified, trigger immediate message delivery.
-      sendCustomMessagesToTarget(customMessageInfo);
+      sendCustomMessageToTarget(message);
     } else if (playbackInfo.timeline == null) {
       // Still waiting for initial timeline to resolve position.
-      customMessageInfos.add(customMessageInfo);
+      customMessageInfos.add(new CustomMessageInfo(message));
     } else {
+      CustomMessageInfo customMessageInfo = new CustomMessageInfo(message);
       if (resolveCustomMessagePosition(customMessageInfo)) {
         customMessageInfos.add(customMessageInfo);
         // Ensure new message is inserted according to playback order.
         Collections.sort(customMessageInfos);
       } else {
-        customMessageInfo.listener.onMessageDeleted();
-      }
-    }
-  }
-
-  private void sendCustomMessagesToTarget(final CustomMessageInfo customMessageInfo) {
-    final Runnable handleMessageRunnable =
-        new Runnable() {
-          @Override
-          public void run() {
-            try {
-              customMessageInfo
-                  .message
-                  .getTarget()
-                  .handleMessage(
-                      customMessageInfo.message.getType(), customMessageInfo.message.getMessage());
-            } catch (ExoPlaybackException e) {
-              eventHandler.obtainMessage(MSG_ERROR, e).sendToTarget();
-            } finally {
-              customMessageInfo.listener.onMessageDelivered();
-              if (customMessageInfo.message.getDeleteAfterDelivery()) {
-                customMessageInfo.listener.onMessageDeleted();
-              }
-              // The message may have caused something to change that now requires us to do
-              // work.
-              handler.sendEmptyMessage(MSG_DO_SOME_WORK);
-            }
-          }
-        };
-    if (customMessageInfo.message.getHandler().getLooper() == handler.getLooper()) {
-      handleMessageRunnable.run();
+        message.markAsProcessed(/* isDelivered= */ false);
+      }
+    }
+  }
+
+  private void sendCustomMessageToTarget(PlayerMessage message) {
+    if (message.getHandler().getLooper() == handler.getLooper()) {
+      deliverCustomMessage(message);
+      // The message may have caused something to change that now requires us to do work.
+      handler.sendEmptyMessage(MSG_DO_SOME_WORK);
     } else {
-      handler.post(
-          new Runnable() {
-            @Override
-            public void run() {
-              customMessageInfo.message.getHandler().post(handleMessageRunnable);
-            }
-          });
+      handler.obtainMessage(MSG_SEND_MESSAGE_TO_TARGET, message).sendToTarget();
+    }
+  }
+
+  private void sendCustomMessageToTargetThread(final PlayerMessage message) {
+    message
+        .getHandler()
+        .post(
+            new Runnable() {
+              @Override
+              public void run() {
+                deliverCustomMessage(message);
+              }
+            });
+  }
+
+  private void deliverCustomMessage(PlayerMessage message) {
+    try {
+      message.getTarget().handleMessage(message.getType(), message.getPayload());
+    } catch (ExoPlaybackException e) {
+      eventHandler.obtainMessage(MSG_ERROR, e).sendToTarget();
+    } finally {
+      message.markAsProcessed(/* isDelivered= */ true);
     }
   }
 
@@ -921,7 +920,7 @@ import java.util.Collections;
     for (int i = customMessageInfos.size() - 1; i >= 0; i--) {
       if (!resolveCustomMessagePosition(customMessageInfos.get(i))) {
         // Remove messages if new position can't be resolved.
-        customMessageInfos.get(i).listener.onMessageDeleted();
+        customMessageInfos.get(i).message.markAsProcessed(/* isDelivered= */ false);
         customMessageInfos.remove(i);
       }
     }
@@ -1003,7 +1002,7 @@ import java.util.Collections;
         && nextInfo.resolvedPeriodIndex == currentPeriodIndex
         && nextInfo.resolvedPeriodTimeUs > oldPeriodPositionUs
         && nextInfo.resolvedPeriodTimeUs <= newPeriodPositionUs) {
-      sendCustomMessagesToTarget(nextInfo);
+      sendCustomMessageToTarget(nextInfo.message);
       if (nextInfo.message.getDeleteAfterDelivery()) {
         customMessageInfos.remove(nextCustomMessageInfoIndex);
       } else {
@@ -1942,15 +1941,13 @@ import java.util.Collections;
   private static final class CustomMessageInfo implements Comparable<CustomMessageInfo> {
 
     public final PlayerMessage message;
-    public final PlayerMessage.Sender.Listener listener;
 
     public int resolvedPeriodIndex;
     public long resolvedPeriodTimeUs;
     public @Nullable Object resolvedPeriodUid;
 
-    public CustomMessageInfo(PlayerMessage message, PlayerMessage.Sender.Listener listener) {
+    public CustomMessageInfo(PlayerMessage message) {
       this.message = message;
-      this.listener = listener;
     }
 
     public void setResolvedPosition(int periodIndex, long periodTimeUs, Object periodUid) {

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

@@ -32,32 +32,21 @@ public final class PlayerMessage {
      * Handles a message delivered to the target.
      *
      * @param messageType The message type.
-     * @param message The message.
+     * @param payload The message payload.
      * @throws ExoPlaybackException If an error occurred whilst handling the message.
      */
-    void handleMessage(int messageType, Object message) throws ExoPlaybackException;
+    void handleMessage(int messageType, Object payload) throws ExoPlaybackException;
   }
 
   /** A sender for messages. */
   public interface Sender {
 
-    /** A listener for message events triggered by the sender. */
-    interface Listener {
-
-      /** Called when the message has been delivered. */
-      void onMessageDelivered();
-
-      /** Called when the message has been deleted. */
-      void onMessageDeleted();
-    }
-
     /**
      * Sends a message.
      *
      * @param message The message to be sent.
-     * @param listener The listener to listen to message events.
      */
-    void sendMessage(PlayerMessage message, Listener listener);
+    void sendMessage(PlayerMessage message);
   }
 
   private final Target target;
@@ -65,14 +54,14 @@ public final class PlayerMessage {
   private final Timeline timeline;
 
   private int type;
-  private Object message;
+  private Object payload;
   private Handler handler;
   private int windowIndex;
   private long positionMs;
   private boolean deleteAfterDelivery;
   private boolean isSent;
   private boolean isDelivered;
-  private boolean isDeleted;
+  private boolean isProcessed;
 
   /**
    * Creates a new message.
@@ -112,9 +101,9 @@ public final class PlayerMessage {
   }
 
   /**
-   * Sets a custom message type forwarded to the {@link Target#handleMessage(int, Object)}.
+   * Sets the message type forwarded to {@link Target#handleMessage(int, Object)}.
    *
-   * @param messageType The custom message type.
+   * @param messageType The message type.
    * @return This message.
    * @throws IllegalStateException If {@link #send()} has already been called.
    */
@@ -124,27 +113,27 @@ public final class PlayerMessage {
     return this;
   }
 
-  /** Returns custom message type forwarded to the {@link Target#handleMessage(int, Object)}. */
+  /** Returns the message type forwarded to {@link Target#handleMessage(int, Object)}. */
   public int getType() {
     return type;
   }
 
   /**
-   * Sets a custom message forwarded to the {@link Target#handleMessage(int, Object)}.
+   * Sets the message payload forwarded to {@link Target#handleMessage(int, Object)}.
    *
-   * @param message The custom message.
+   * @param payload The message payload.
    * @return This message.
    * @throws IllegalStateException If {@link #send()} has already been called.
    */
-  public PlayerMessage setMessage(@Nullable Object message) {
+  public PlayerMessage setPayload(@Nullable Object payload) {
     Assertions.checkState(!isSent);
-    this.message = message;
+    this.payload = payload;
     return this;
   }
 
-  /** Returns custom message forwarded to the {@link Target#handleMessage(int, Object)}. */
-  public Object getMessage() {
-    return message;
+  /** Returns the message payload forwarded to {@link Target#handleMessage(int, Object)}. */
+  public Object getPayload() {
+    return payload;
   }
 
   /**
@@ -248,25 +237,7 @@ public final class PlayerMessage {
       Assertions.checkArgument(deleteAfterDelivery);
     }
     isSent = true;
-    sender.sendMessage(
-        this,
-        new Sender.Listener() {
-          @Override
-          public void onMessageDelivered() {
-            synchronized (PlayerMessage.this) {
-              isDelivered = true;
-              PlayerMessage.this.notifyAll();
-            }
-          }
-
-          @Override
-          public void onMessageDeleted() {
-            synchronized (PlayerMessage.this) {
-              isDeleted = true;
-              PlayerMessage.this.notifyAll();
-            }
-          }
-        });
+    sender.sendMessage(this);
     return this;
   }
 
@@ -287,9 +258,23 @@ public final class PlayerMessage {
   public synchronized boolean blockUntilDelivered() throws InterruptedException {
     Assertions.checkState(isSent);
     Assertions.checkState(handler.getLooper().getThread() != Thread.currentThread());
-    while (!isDelivered && !isDeleted) {
+    while (!isProcessed) {
       wait();
     }
     return isDelivered;
   }
+
+  /**
+   * Marks the message as processed. Should only be called by a {@link Sender} and may be called
+   * multiple times.
+   *
+   * @param isDelivered Whether the message has been delivered to its target. The message is
+   *     considered as being delivered when this method has been called with {@code isDelivered} set
+   *     to true at least once.
+   */
+  public synchronized void markAsProcessed(boolean isDelivered) {
+    this.isDelivered |= isDelivered;
+    isProcessed = true;
+    notifyAll();
+  }
 }

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

@@ -41,6 +41,7 @@ import com.google.android.exoplayer2.trackselection.TrackSelector;
 import com.google.android.exoplayer2.util.Clock;
 import com.google.android.exoplayer2.util.Util;
 import com.google.android.exoplayer2.video.VideoRendererEventListener;
+import java.util.ArrayList;
 import java.util.List;
 import java.util.concurrent.CopyOnWriteArraySet;
 
@@ -168,7 +169,7 @@ public class SimpleExoPlayer implements ExoPlayer {
         player
             .createMessage(renderer)
             .setType(C.MSG_SET_SCALING_MODE)
-            .setMessage(videoScalingMode)
+            .setPayload(videoScalingMode)
             .send();
       }
     }
@@ -357,7 +358,7 @@ public class SimpleExoPlayer implements ExoPlayer {
         player
             .createMessage(renderer)
             .setType(C.MSG_SET_AUDIO_ATTRIBUTES)
-            .setMessage(audioAttributes)
+            .setPayload(audioAttributes)
             .send();
       }
     }
@@ -379,7 +380,7 @@ public class SimpleExoPlayer implements ExoPlayer {
     this.audioVolume = audioVolume;
     for (Renderer renderer : renderers) {
       if (renderer.getTrackType() == C.TRACK_TYPE_AUDIO) {
-        player.createMessage(renderer).setType(C.MSG_SET_VOLUME).setMessage(audioVolume).send();
+        player.createMessage(renderer).setType(C.MSG_SET_VOLUME).setPayload(audioVolume).send();
       }
     }
   }
@@ -911,21 +912,22 @@ public class SimpleExoPlayer implements ExoPlayer {
   private void setVideoSurfaceInternal(Surface surface, boolean ownsSurface) {
     // Note: We don't turn this method into a no-op if the surface is being replaced with itself
     // so as to ensure onRenderedFirstFrame callbacks are still called in this case.
-    boolean surfaceReplaced = this.surface != null && this.surface != surface;
+    List<PlayerMessage> messages = new ArrayList<>();
     for (Renderer renderer : renderers) {
       if (renderer.getTrackType() == C.TRACK_TYPE_VIDEO) {
-        PlayerMessage message =
-            player.createMessage(renderer).setType(C.MSG_SET_SURFACE).setMessage(surface).send();
-        if (surfaceReplaced) {
-          try {
-            message.blockUntilDelivered();
-          } catch (InterruptedException e) {
-            Thread.currentThread().interrupt();
-          }
-        }
+        messages.add(
+            player.createMessage(renderer).setType(C.MSG_SET_SURFACE).setPayload(surface).send());
       }
     }
-    if (surfaceReplaced) {
+    if (this.surface != null && this.surface != surface) {
+      // We're replacing a surface. Block to ensure that it's not accessed after the method returns.
+      try {
+        for (PlayerMessage message : messages) {
+          message.blockUntilDelivered();
+        }
+      } catch (InterruptedException e) {
+        Thread.currentThread().interrupt();
+      }
       // If we created the previous surface, we are responsible for releasing it.
       if (this.ownsSurface) {
         this.surface.release();

library/core/src/main/java/com/google/android/exoplayer2/source/DynamicConcatenatingMediaSource.java

@@ -149,7 +149,7 @@ public final class DynamicConcatenatingMediaSource implements MediaSource, Playe
       player
           .createMessage(this)
           .setType(MSG_ADD)
-          .setMessage(new MessageData<>(index, mediaSource, actionOnCompletion))
+          .setPayload(new MessageData<>(index, mediaSource, actionOnCompletion))
           .send();
     } else if (actionOnCompletion != null) {
       actionOnCompletion.run();
@@ -225,7 +225,7 @@ public final class DynamicConcatenatingMediaSource implements MediaSource, Playe
       player
           .createMessage(this)
           .setType(MSG_ADD_MULTIPLE)
-          .setMessage(new MessageData<>(index, mediaSources, actionOnCompletion))
+          .setPayload(new MessageData<>(index, mediaSources, actionOnCompletion))
           .send();
     } else if (actionOnCompletion != null){
       actionOnCompletion.run();
@@ -264,7 +264,7 @@ public final class DynamicConcatenatingMediaSource implements MediaSource, Playe
       player
           .createMessage(this)
           .setType(MSG_REMOVE)
-          .setMessage(new MessageData<>(index, null, actionOnCompletion))
+          .setPayload(new MessageData<>(index, null, actionOnCompletion))
           .send();
     } else if (actionOnCompletion != null) {
       actionOnCompletion.run();
@@ -304,7 +304,7 @@ public final class DynamicConcatenatingMediaSource implements MediaSource, Playe
       player
           .createMessage(this)
           .setType(MSG_MOVE)
-          .setMessage(new MessageData<>(currentIndex, newIndex, actionOnCompletion))
+          .setPayload(new MessageData<>(currentIndex, newIndex, actionOnCompletion))
           .send();
     } else if (actionOnCompletion != null) {
       actionOnCompletion.run();
@@ -438,7 +438,7 @@ public final class DynamicConcatenatingMediaSource implements MediaSource, Playe
           new ConcatenatedTimeline(mediaSourceHolders, windowCount, periodCount, shuffleOrder),
           null);
       if (actionOnCompletion != null) {
-        player.createMessage(this).setType(MSG_ON_COMPLETION).setMessage(actionOnCompletion).send();
+        player.createMessage(this).setType(MSG_ON_COMPLETION).setPayload(actionOnCompletion).send();
       }
     }
   }

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

@@ -24,7 +24,6 @@ import android.os.Handler;
 import android.os.HandlerThread;
 import android.os.Looper;
 import android.os.Message;
-import android.util.Pair;
 import com.google.android.exoplayer2.ExoPlaybackException;
 import com.google.android.exoplayer2.PlayerMessage;
 import com.google.android.exoplayer2.Timeline;
@@ -299,22 +298,17 @@ public class MediaSourceTestRunner {
     }
 
     @Override
-    public void sendMessage(PlayerMessage message, Listener listener) {
-      handler.obtainMessage(0, Pair.create(message, listener)).sendToTarget();
+    public void sendMessage(PlayerMessage message) {
+      handler.obtainMessage(0, message).sendToTarget();
     }
 
     @Override
     @SuppressWarnings("unchecked")
     public boolean handleMessage(Message msg) {
-      Pair<PlayerMessage, Listener> messageAndListener = (Pair<PlayerMessage, Listener>) msg.obj;
+      PlayerMessage message = (PlayerMessage) msg.obj;
       try {
-        messageAndListener
-            .first
-            .getTarget()
-            .handleMessage(
-                messageAndListener.first.getType(), messageAndListener.first.getMessage());
-        messageAndListener.second.onMessageDelivered();
-        messageAndListener.second.onMessageDeleted();
+        message.getTarget().handleMessage(message.getType(), message.getPayload());
+        message.markAsProcessed(/* isDelivered= */ true);
       } catch (ExoPlaybackException e) {
         fail("Unexpected ExoPlaybackException.");
       }