Mark @C.SelectionReason as TYPE_USE (only) and use it in more places

This is not backwards compatible if the @SelectionReason annotation is
used in Kotlin code, but before this change there aren't many library
surfaces that return a value annotated with @SelectionReason, so it
seems relatively unlikely that it is in use in any/many apps.

A follow-up change will fix the positions of existing usages to match
this new config.

#minor-release

PiperOrigin-RevId: 426409877

RELEASENOTES.md

@@ -169,6 +169,10 @@
         a fallback value.
     *   Remove `(Simple)ExoPlayer.setThrowsWhenUsingWrongThread`. Opting out of
         the thread enforcement is no longer possible.
+*   Change the following `IntDefs` to `@Target(TYPE_USE)` only. This may break
+    the compilation of usages in Kotlin, which can be fixed by moving the
+    annotation to annotate the type (`Int`).
+    *   `@C.SelectionReason`
 
 ### 2.16.1 (2021-11-18)
 

library/common/src/main/java/com/google/android/exoplayer2/C.java

@@ -729,6 +729,7 @@ public final class C {
    */
   @Documented
   @Retention(RetentionPolicy.SOURCE)
+  @Target(TYPE_USE)
   @IntDef(
       open = true,
       value = {

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

@@ -41,7 +41,7 @@ public final class MediaLoadData {
    * One of the {@link SelectionReason selection reasons} if the data belongs to a track. {@link
    * C#SELECTION_REASON_UNKNOWN} otherwise.
    */
-  public final int trackSelectionReason;
+  public final @C.SelectionReason int trackSelectionReason;
   /**
    * Optional data associated with the selection of the track to which the data belongs. Null if the
    * data does not belong to a track.

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

@@ -546,7 +546,7 @@ import org.checkerframework.checker.nullness.qual.MonotonicNonNull;
     }
 
     @Override
-    public int getSelectionReason() {
+    public @C.SelectionReason int getSelectionReason() {
       return trackSelection.getSelectionReason();
     }
 

library/core/src/main/java/com/google/android/exoplayer2/trackselection/AdaptiveTrackSelection.java

@@ -313,7 +313,7 @@ public class AdaptiveTrackSelection extends BaseTrackSelection {
 
   private float playbackSpeed;
   private int selectedIndex;
-  private int reason;
+  private @C.SelectionReason int reason;
   private long lastBufferEvaluationMs;
   @Nullable private MediaChunk lastBufferEvaluationMediaChunk;
 
@@ -446,7 +446,7 @@ public class AdaptiveTrackSelection extends BaseTrackSelection {
     }
 
     int previousSelectedIndex = selectedIndex;
-    int previousReason = reason;
+    @C.SelectionReason int previousReason = reason;
     int formatIndexOfPreviousChunk =
         queue.isEmpty() ? C.INDEX_UNSET : indexOf(Iterables.getLast(queue).trackFormat);
     if (formatIndexOfPreviousChunk != C.INDEX_UNSET) {
@@ -484,7 +484,7 @@ public class AdaptiveTrackSelection extends BaseTrackSelection {
   }
 
   @Override
-  public int getSelectionReason() {
+  public @C.SelectionReason int getSelectionReason() {
     return reason;
   }
 

library/core/src/main/java/com/google/android/exoplayer2/trackselection/ExoTrackSelection.java

@@ -122,6 +122,7 @@ public interface ExoTrackSelection extends TrackSelection {
   int getSelectedIndex();
 
   /** Returns the reason for the current track selection. */
+  @C.SelectionReason
   int getSelectionReason();
 
   /** Returns optional data associated with the current track selection. */

library/core/src/main/java/com/google/android/exoplayer2/trackselection/FixedTrackSelection.java

@@ -25,7 +25,7 @@ import java.util.List;
 /** A {@link TrackSelection} consisting of a single track. */
 public final class FixedTrackSelection extends BaseTrackSelection {
 
-  private final int reason;
+  private final @C.SelectionReason int reason;
   @Nullable private final Object data;
 
   /**
@@ -53,7 +53,11 @@ public final class FixedTrackSelection extends BaseTrackSelection {
    * @param data Optional data associated with the track selection.
    */
   public FixedTrackSelection(
-      TrackGroup group, int track, @Type int type, int reason, @Nullable Object data) {
+      TrackGroup group,
+      int track,
+      @Type int type,
+      @C.SelectionReason int reason,
+      @Nullable Object data) {
     super(group, /* tracks= */ new int[] {track}, type);
     this.reason = reason;
     this.data = data;
@@ -75,7 +79,7 @@ public final class FixedTrackSelection extends BaseTrackSelection {
   }
 
   @Override
-  public int getSelectionReason() {
+  public @C.SelectionReason int getSelectionReason() {
     return reason;
   }
 

library/hls/src/main/java/com/google/android/exoplayer2/source/hls/HlsChunkSource.java

@@ -915,7 +915,7 @@ import org.checkerframework.checker.nullness.qual.MonotonicNonNull;
     }
 
     @Override
-    public int getSelectionReason() {
+    public @C.SelectionReason int getSelectionReason() {
       return C.SELECTION_REASON_UNKNOWN;
     }
 

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

@@ -114,7 +114,7 @@ public final class FakeTrackSelection implements ExoTrackSelection {
   }
 
   @Override
-  public int getSelectionReason() {
+  public @C.SelectionReason int getSelectionReason() {
     return C.SELECTION_REASON_UNKNOWN;
   }
 

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

@@ -238,7 +238,7 @@ public final class MediaPeriodAsserts {
     }
 
     @Override
-    public int getSelectionReason() {
+    public @C.SelectionReason int getSelectionReason() {
       return C.SELECTION_REASON_UNKNOWN;
     }