Fix track selection nullability issues.

-------------
Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=199266768

library/core/build.gradle

@@ -54,6 +54,7 @@ android {
 dependencies {
     implementation 'com.android.support:support-annotations:' + supportLibraryVersion
     compileOnly 'org.checkerframework:checker-qual:' + checkerframeworkVersion
+    compileOnly 'org.checkerframework:checker-compat-qual:' + checkerframeworkVersion
     androidTestImplementation 'com.google.dexmaker:dexmaker:' + dexmakerVersion
     androidTestImplementation 'com.google.dexmaker:dexmaker-mockito:' + dexmakerVersion
     androidTestImplementation 'com.google.truth:truth:' + truthVersion

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

@@ -15,6 +15,7 @@
  */
 package com.google.android.exoplayer2.trackselection;
 
+import android.support.annotation.Nullable;
 import com.google.android.exoplayer2.C;
 import com.google.android.exoplayer2.Format;
 import com.google.android.exoplayer2.source.TrackGroup;
@@ -242,9 +243,11 @@ public class AdaptiveTrackSelection extends BaseTrackSelection {
     this.minTimeBetweenBufferReevaluationMs = minTimeBetweenBufferReevaluationMs;
     this.clock = clock;
     playbackSpeed = 1f;
-    selectedIndex = determineIdealSelectedIndex(Long.MIN_VALUE);
     reason = C.SELECTION_REASON_INITIAL;
     lastBufferEvaluationMs = C.TIME_UNSET;
+    @SuppressWarnings("nullness:method.invocation.invalid")
+    int selectedIndex = determineIdealSelectedIndex(Long.MIN_VALUE);
+    this.selectedIndex = selectedIndex;
   }
 
   @Override
@@ -301,7 +304,7 @@ public class AdaptiveTrackSelection extends BaseTrackSelection {
   }
 
   @Override
-  public Object getSelectionData() {
+  public @Nullable Object getSelectionData() {
     return null;
   }
 

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

@@ -15,6 +15,7 @@
  */
 package com.google.android.exoplayer2.trackselection;
 
+import android.support.annotation.Nullable;
 import com.google.android.exoplayer2.C;
 import com.google.android.exoplayer2.source.TrackGroup;
 import com.google.android.exoplayer2.util.Assertions;
@@ -30,7 +31,7 @@ public final class FixedTrackSelection extends BaseTrackSelection {
   public static final class Factory implements TrackSelection.Factory {
 
     private final int reason;
-    private final Object data;
+    private final @Nullable Object data;
 
     public Factory() {
       this.reason = C.SELECTION_REASON_UNKNOWN;
@@ -41,7 +42,7 @@ public final class FixedTrackSelection extends BaseTrackSelection {
      * @param reason A reason for the track selection.
      * @param data Optional data associated with the track selection.
      */
-    public Factory(int reason, Object data) {
+    public Factory(int reason, @Nullable Object data) {
       this.reason = reason;
       this.data = data;
     }
@@ -51,11 +52,10 @@ public final class FixedTrackSelection extends BaseTrackSelection {
       Assertions.checkArgument(tracks.length == 1);
       return new FixedTrackSelection(group, tracks[0], reason, data);
     }
-
   }
 
   private final int reason;
-  private final Object data;
+  private final @Nullable Object data;
 
   /**
    * @param group The {@link TrackGroup}. Must not be null.
@@ -71,7 +71,7 @@ public final class FixedTrackSelection extends BaseTrackSelection {
    * @param reason A reason for the track selection.
    * @param data Optional data associated with the track selection.
    */
-  public FixedTrackSelection(TrackGroup group, int track, int reason, Object data) {
+  public FixedTrackSelection(TrackGroup group, int track, int reason, @Nullable Object data) {
     super(group, track);
     this.reason = reason;
     this.data = data;
@@ -94,7 +94,7 @@ public final class FixedTrackSelection extends BaseTrackSelection {
   }
 
   @Override
-  public Object getSelectionData() {
+  public @Nullable Object getSelectionData() {
     return data;
   }
 

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

@@ -16,6 +16,7 @@
 package com.google.android.exoplayer2.trackselection;
 
 import android.support.annotation.IntDef;
+import android.support.annotation.Nullable;
 import android.util.Pair;
 import com.google.android.exoplayer2.C;
 import com.google.android.exoplayer2.ExoPlaybackException;
@@ -28,6 +29,7 @@ import com.google.android.exoplayer2.util.Util;
 import java.lang.annotation.Retention;
 import java.lang.annotation.RetentionPolicy;
 import java.util.Arrays;
+import org.checkerframework.checker.nullness.compatqual.NullableType;
 
 /**
  * Base class for {@link TrackSelector}s that first establish a mapping between {@link TrackGroup}s
@@ -301,13 +303,13 @@ public abstract class MappingTrackSelector extends TrackSelector {
 
   }
 
-  private MappedTrackInfo currentMappedTrackInfo;
+  private @Nullable MappedTrackInfo currentMappedTrackInfo;
 
   /**
    * Returns the mapping information for the currently active track selection, or null if no
    * selection is currently active.
    */
-  public final MappedTrackInfo getCurrentMappedTrackInfo() {
+  public final @Nullable MappedTrackInfo getCurrentMappedTrackInfo() {
     return currentMappedTrackInfo;
   }
 
@@ -357,9 +359,11 @@ public abstract class MappingTrackSelector extends TrackSelector {
     int[] rendererTrackTypes = new int[rendererCapabilities.length];
     for (int i = 0; i < rendererCapabilities.length; i++) {
       int rendererTrackGroupCount = rendererTrackGroupCounts[i];
-      rendererTrackGroupArrays[i] = new TrackGroupArray(
-          Arrays.copyOf(rendererTrackGroups[i], rendererTrackGroupCount));
-      rendererFormatSupports[i] = Arrays.copyOf(rendererFormatSupports[i], rendererTrackGroupCount);
+      rendererTrackGroupArrays[i] =
+          new TrackGroupArray(
+              Util.nullSafeArrayCopy(rendererTrackGroups[i], rendererTrackGroupCount));
+      rendererFormatSupports[i] =
+          Util.nullSafeArrayCopy(rendererFormatSupports[i], rendererTrackGroupCount);
       rendererTrackTypes[i] = rendererCapabilities[i].getTrackType();
     }
 
@@ -367,7 +371,7 @@ public abstract class MappingTrackSelector extends TrackSelector {
     int unmappedTrackGroupCount = rendererTrackGroupCounts[rendererCapabilities.length];
     TrackGroupArray unmappedTrackGroupArray =
         new TrackGroupArray(
-            Arrays.copyOf(
+            Util.nullSafeArrayCopy(
                 rendererTrackGroups[rendererCapabilities.length], unmappedTrackGroupCount));
 
     // Package up the track information and selections.
@@ -379,7 +383,7 @@ public abstract class MappingTrackSelector extends TrackSelector {
             rendererFormatSupports,
             unmappedTrackGroupArray);
 
-    Pair<RendererConfiguration[], TrackSelection[]> result =
+    Pair<@NullableType RendererConfiguration[], @NullableType TrackSelection[]> result =
         selectTracks(
             mappedTrackInfo, rendererFormatSupports, rendererMixedMimeTypeAdaptationSupports);
     return new TrackSelectorResult(result.first, result.second, mappedTrackInfo);
@@ -399,11 +403,12 @@ public abstract class MappingTrackSelector extends TrackSelector {
    *     RendererCapabilities#getTrackType()} is {@link C#TRACK_TYPE_NONE}.
    * @throws ExoPlaybackException If an error occurs while selecting the tracks.
    */
-  protected abstract Pair<RendererConfiguration[], TrackSelection[]> selectTracks(
-      MappedTrackInfo mappedTrackInfo,
-      int[][][] rendererFormatSupports,
-      int[] rendererMixedMimeTypeAdaptationSupport)
-      throws ExoPlaybackException;
+  protected abstract Pair<@NullableType RendererConfiguration[], @NullableType TrackSelection[]>
+      selectTracks(
+          MappedTrackInfo mappedTrackInfo,
+          int[][][] rendererFormatSupports,
+          int[] rendererMixedMimeTypeAdaptationSupport)
+          throws ExoPlaybackException;
 
   /**
    * Finds the renderer to which the provided {@link TrackGroup} should be mapped.

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

@@ -16,6 +16,7 @@
 package com.google.android.exoplayer2.trackselection;
 
 import android.os.SystemClock;
+import android.support.annotation.Nullable;
 import com.google.android.exoplayer2.C;
 import com.google.android.exoplayer2.source.TrackGroup;
 import java.util.Random;
@@ -47,7 +48,6 @@ public final class RandomTrackSelection extends BaseTrackSelection {
     public RandomTrackSelection createTrackSelection(TrackGroup group, int... tracks) {
       return new RandomTrackSelection(group, tracks, random);
     }
-
   }
 
   private final Random random;
@@ -123,7 +123,7 @@ public final class RandomTrackSelection extends BaseTrackSelection {
   }
 
   @Override
-  public Object getSelectionData() {
+  public @Nullable Object getSelectionData() {
     return null;
   }
 

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

@@ -15,6 +15,7 @@
  */
 package com.google.android.exoplayer2.trackselection;
 
+import android.support.annotation.Nullable;
 import com.google.android.exoplayer2.C;
 import com.google.android.exoplayer2.Format;
 import com.google.android.exoplayer2.source.TrackGroup;
@@ -129,10 +130,8 @@ public interface TrackSelection {
    */
   int getSelectionReason();
 
-  /**
-   * Returns optional data associated with the current track selection.
-   */
-  Object getSelectionData();
+  /** Returns optional data associated with the current track selection. */
+  @Nullable Object getSelectionData();
 
   // Adaptation.
 

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

@@ -17,6 +17,7 @@ package com.google.android.exoplayer2.trackselection;
 
 import android.support.annotation.Nullable;
 import java.util.Arrays;
+import org.checkerframework.checker.nullness.compatqual.NullableType;
 
 /** An array of {@link TrackSelection}s. */
 public final class TrackSelectionArray {
@@ -24,15 +25,13 @@ public final class TrackSelectionArray {
   /** The length of this array. */
   public final int length;
 
-  private final TrackSelection[] trackSelections;
+  private final @NullableType TrackSelection[] trackSelections;
 
   // Lazily initialized hashcode.
   private int hashCode;
 
-  /**
-   * @param trackSelections The selections. Must not be null, but may contain null elements.
-   */
-  public TrackSelectionArray(TrackSelection... trackSelections) {
+  /** @param trackSelections The selections. Must not be null, but may contain null elements. */
+  public TrackSelectionArray(@NullableType TrackSelection... trackSelections) {
     this.trackSelections = trackSelections;
     this.length = trackSelections.length;
   }
@@ -43,14 +42,12 @@ public final class TrackSelectionArray {
    * @param index The index of the selection.
    * @return The selection.
    */
-  public TrackSelection get(int index) {
+  public @Nullable TrackSelection get(int index) {
     return trackSelections[index];
   }
 
-  /**
-   * Returns the selections in a newly allocated array.
-   */
-  public TrackSelection[] getAll() {
+  /** Returns the selections in a newly allocated array. */
+  public @NullableType TrackSelection[] getAll() {
     return trackSelections.clone();
   }
 

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

@@ -15,6 +15,7 @@
  */
 package com.google.android.exoplayer2.trackselection;
 
+import android.support.annotation.Nullable;
 import com.google.android.exoplayer2.ExoPlaybackException;
 import com.google.android.exoplayer2.ExoPlayer;
 import com.google.android.exoplayer2.Renderer;
@@ -89,7 +90,7 @@ public abstract class TrackSelector {
 
   }
 
-  private InvalidationListener listener;
+  private @Nullable InvalidationListener listener;
 
   /**
    * Called by the player to initialize the selector.

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

@@ -17,6 +17,7 @@ package com.google.android.exoplayer2.trackselection;
 
 import com.google.android.exoplayer2.RendererConfiguration;
 import com.google.android.exoplayer2.util.Util;
+import org.checkerframework.checker.nullness.compatqual.NullableType;
 
 /**
  * The result of a {@link TrackSelector} operation.
@@ -29,7 +30,7 @@ public final class TrackSelectorResult {
    * A {@link RendererConfiguration} for each renderer. A null entry indicates the corresponding
    * renderer should be disabled.
    */
-  public final RendererConfiguration[] rendererConfigurations;
+  public final @NullableType RendererConfiguration[] rendererConfigurations;
   /**
    * A {@link TrackSelectionArray} containing the track selection for each renderer.
    */
@@ -48,7 +49,9 @@ public final class TrackSelectorResult {
    *     TrackSelector#onSelectionActivated(Object)} should the selection be activated.
    */
   public TrackSelectorResult(
-      RendererConfiguration[] rendererConfigurations, TrackSelection[] selections, Object info) {
+      @NullableType RendererConfiguration[] rendererConfigurations,
+      @NullableType TrackSelection[] selections,
+      Object info) {
     this.rendererConfigurations = rendererConfigurations;
     this.selections = new TrackSelectionArray(selections);
     this.info = info;

library/core/src/main/java/com/google/android/exoplayer2/util/Util.java

@@ -311,10 +311,10 @@ public final class Util {
    * Returns a normalized RFC 639-2/T code for {@code language}.
    *
    * @param language A case-insensitive ISO 639 alpha-2 or alpha-3 language code.
-   * @return The all-lowercase normalized code, or null if the input was null, or
-   *     {@code language.toLowerCase()} if the language could not be normalized.
+   * @return The all-lowercase normalized code, or null if the input was null, or {@code
+   *     language.toLowerCase()} if the language could not be normalized.
    */
-  public static String normalizeLanguageCode(String language) {
+  public static @Nullable String normalizeLanguageCode(@Nullable String language) {
     try {
       return language == null ? null : new Locale(language).getISO3Language();
     } catch (MissingResourceException e) {

library/ui/src/main/java/com/google/android/exoplayer2/ui/TrackSelectionView.java

@@ -203,7 +203,9 @@ public class TrackSelectionView extends LinearLayout {
       removeViewAt(i);
     }
 
-    if (trackSelector == null) {
+    MappingTrackSelector.MappedTrackInfo trackInfo =
+        trackSelector == null ? null : trackSelector.getCurrentMappedTrackInfo();
+    if (trackSelector == null || trackInfo == null) {
       // The view is not initialized.
       disableView.setEnabled(false);
       defaultView.setEnabled(false);
@@ -212,7 +214,6 @@ public class TrackSelectionView extends LinearLayout {
     disableView.setEnabled(true);
     defaultView.setEnabled(true);
 
-    MappingTrackSelector.MappedTrackInfo trackInfo = trackSelector.getCurrentMappedTrackInfo();
     trackGroups = trackInfo.getTrackGroups(rendererIndex);
 
     DefaultTrackSelector.Parameters parameters = trackSelector.getParameters();