Add SessionPlayer#movePlaylistItem(int, int) support

extensions/media2/src/androidTest/java/com/google/android/exoplayer2/ext/media2/SessionPlayerConnectorTest.java

@@ -931,6 +931,38 @@ public class SessionPlayerConnectorTest {
     assertThat(onPlaylistChangedLatch.getCount()).isEqualTo(1);
   }
 
+  @Test
+  @LargeTest
+  @SdkSuppress(minSdkVersion = Build.VERSION_CODES.KITKAT)
+  public void movePlaylistItem_calledOnlyOnce_notifiesPlaylistChangeOnlyOnce() throws Exception {
+    List<MediaItem> playlist = new ArrayList<>();
+    playlist.add(TestUtils.createMediaItem(R.raw.video_1));
+    playlist.add(TestUtils.createMediaItem(R.raw.video_2));
+    playlist.add(TestUtils.createMediaItem(R.raw.video_3));
+    assertPlayerResultSuccess(sessionPlayerConnector.setPlaylist(playlist, /* metadata= */ null));
+    assertPlayerResultSuccess(sessionPlayerConnector.prepare());
+
+    CountDownLatch onPlaylistChangedLatch = new CountDownLatch(2);
+    int moveFromIndex = 0;
+    int moveToIndex = 2;
+    playlist.add(moveToIndex, playlist.remove(moveFromIndex));
+    sessionPlayerConnector.registerPlayerCallback(
+        executor,
+        new SessionPlayer.PlayerCallback() {
+          @Override
+          public void onPlaylistChanged(
+              SessionPlayer player,
+              @Nullable List<MediaItem> list,
+              @Nullable MediaMetadata metadata) {
+            assertThat(list).isEqualTo(playlist);
+            onPlaylistChangedLatch.countDown();
+          }
+        });
+    sessionPlayerConnector.movePlaylistItem(moveFromIndex, moveToIndex);
+    assertThat(onPlaylistChangedLatch.await(PLAYLIST_CHANGE_WAIT_TIME_MS, MILLISECONDS)).isFalse();
+    assertThat(onPlaylistChangedLatch.getCount()).isEqualTo(1);
+  }
+
   // TODO(b/168860979): De-flake and re-enable.
   @Ignore
   @Test

extensions/media2/src/main/java/com/google/android/exoplayer2/ext/media2/PlayerCommandQueue.java

@@ -97,6 +97,8 @@ import java.util.concurrent.Callable;
   /** Command code for {@link SessionPlayer#removePlaylistItem(int)} */
   public static final int COMMAND_CODE_PLAYER_REMOVE_PLAYLIST_ITEM = 16;
 
+  /** Command code for {@link SessionPlayer#movePlaylistItem(int, int)} */
+  public static final int COMMAND_CODE_PLAYER_MOVE_PLAYLIST_ITEM = 17;
   /** List of session commands whose result would be set after the command is finished. */
   @Documented
   @Retention(RetentionPolicy.SOURCE)
@@ -119,6 +121,7 @@ import java.util.concurrent.Callable;
         COMMAND_CODE_PLAYER_SET_PLAYLIST,
         COMMAND_CODE_PLAYER_ADD_PLAYLIST_ITEM,
         COMMAND_CODE_PLAYER_REMOVE_PLAYLIST_ITEM,
+        COMMAND_CODE_PLAYER_MOVE_PLAYLIST_ITEM,
       })
   public @interface CommandCode {}
 

extensions/media2/src/main/java/com/google/android/exoplayer2/ext/media2/PlayerWrapper.java

@@ -223,6 +223,18 @@ import java.util.List;
     return true;
   }
 
+  public boolean movePlaylistItem(@IntRange(from = 0) int fromIndex, @IntRange(from = 0) int toIndex) {
+    int itemCount = player.getMediaItemCount();
+    if (!(fromIndex < itemCount && toIndex < itemCount)) {
+      return false;
+    }
+    if (fromIndex == toIndex) {
+      return true;
+    }
+    player.moveMediaItem(fromIndex, toIndex);
+    return true;
+  }
+
   public boolean skipToPreviousPlaylistItem() {
     Timeline timeline = player.getCurrentTimeline();
     Assertions.checkState(!timeline.isEmpty());

extensions/media2/src/main/java/com/google/android/exoplayer2/ext/media2/SessionCallback.java

@@ -226,7 +226,7 @@ import java.util.concurrent.TimeoutException;
       build = new SessionCommandGroup.Builder();
     }
 
-    build.addAllPredefinedCommands(SessionCommand.COMMAND_VERSION_1);
+    build.addAllPredefinedCommands(SessionCommand.COMMAND_VERSION_2);
     // TODO(internal b/142848015): Use removeCommand(int) when it's added.
     if (mediaItemProvider == null) {
       build.removeCommand(new SessionCommand(SessionCommand.COMMAND_CODE_PLAYER_SET_MEDIA_ITEM));
@@ -234,6 +234,7 @@ import java.util.concurrent.TimeoutException;
       build.removeCommand(new SessionCommand(SessionCommand.COMMAND_CODE_PLAYER_ADD_PLAYLIST_ITEM));
       build.removeCommand(
           new SessionCommand(SessionCommand.COMMAND_CODE_PLAYER_REPLACE_PLAYLIST_ITEM));
+      build.removeCommand(new SessionCommand(SessionCommand.COMMAND_CODE_PLAYER_MOVE_PLAYLIST_ITEM));
     }
     if (ratingCallback == null) {
       build.removeCommand(new SessionCommand(SessionCommand.COMMAND_CODE_SESSION_SET_RATING));

extensions/media2/src/main/java/com/google/android/exoplayer2/ext/media2/SessionPlayerConnector.java

@@ -324,6 +324,17 @@ public final class SessionPlayerConnector extends SessionPlayer {
     return result;
   }
 
+  @Override
+  public ListenableFuture<PlayerResult> movePlaylistItem(int fromIndex, int toIndex) {
+    Assertions.checkArgument(fromIndex >= 0);
+    Assertions.checkArgument(toIndex >= 0);
+    ListenableFuture<PlayerResult> result =
+        playerCommandQueue.addCommand(
+            PlayerCommandQueue.COMMAND_CODE_PLAYER_MOVE_PLAYLIST_ITEM,
+            /* command= */ () -> player.movePlaylistItem(fromIndex, toIndex));
+    return result;
+  }
+
   @Override
   public ListenableFuture<PlayerResult> skipToPreviousPlaylistItem() {
     ListenableFuture<PlayerResult> result =