Expose a few APIs in util collections.

These are either already exposed on other specialized collection variants or are exposed as public API on the androidx versions, or both.

With these APIs exposed, all of the unsupported app usage can be done through public API. As a result, all unsupported app usage is now locked to apps targeting API 28 or earlier.

Bug: 116877302
Test: none, no implementation change
Change-Id: I548d71319bffb0a6b529e380ea936df674dbf515

1 files changed, 11 insertions, 10 deletions

diff --git a/core/java/android/util/ArraySet.java b/core/java/android/util/ArraySet.java
index 526a950b4820..d74a0fe8d2c1 100644
--- a/core/java/android/util/ArraySet.java
+++ b/core/java/android/util/ArraySet.java
@@ -71,15 +71,15 @@ public final class ArraySet<E> implements Collection<E>, Set<E> {
     static int sTwiceBaseCacheSize;
 
     final boolean mIdentityHashCode;
-    @UnsupportedAppUsage
+    @UnsupportedAppUsage(maxTargetSdk = 28) // Hashes are an implementation detail. Use public API.
     int[] mHashes;
-    @UnsupportedAppUsage
+    @UnsupportedAppUsage(maxTargetSdk = 28) // Storage is an implementation detail. Use public API.
     Object[] mArray;
-    @UnsupportedAppUsage
+    @UnsupportedAppUsage(maxTargetSdk = 28) // Use size()
     int mSize;
     MapCollections<E, E> mCollections;
 
-    @UnsupportedAppUsage
+    @UnsupportedAppUsage(maxTargetSdk = 28) // Hashes are an implementation detail. Use indexOfKey(Object).
     private int indexOf(Object key, int hash) {
         final int N = mSize;
 
@@ -118,7 +118,7 @@ public final class ArraySet<E> implements Collection<E>, Set<E> {
         return ~end;
     }
 
-    @UnsupportedAppUsage
+    @UnsupportedAppUsage(maxTargetSdk = 28) // Use indexOf(null)
     private int indexOfNull() {
         final int N = mSize;
 
@@ -157,7 +157,7 @@ public final class ArraySet<E> implements Collection<E>, Set<E> {
         return ~end;
     }
 
-    @UnsupportedAppUsage
+    @UnsupportedAppUsage(maxTargetSdk = 28) // Allocations are an implementation detail.
     private void allocArrays(final int size) {
         if (size == (BASE_SIZE * 2)) {
             synchronized (ArraySet.class) {
@@ -215,7 +215,7 @@ public final class ArraySet<E> implements Collection<E>, Set<E> {
         mArray = new Object[size];
     }
 
-    @UnsupportedAppUsage
+    @UnsupportedAppUsage(maxTargetSdk = 28) // Allocations are an implementation detail.
     private static void freeArrays(final int[] hashes, final Object[] array, final int size) {
         if (hashes.length == (BASE_SIZE * 2)) {
             synchronized (ArraySet.class) {
@@ -289,9 +289,10 @@ public final class ArraySet<E> implements Collection<E>, Set<E> {
         }
     }
 
-    /** {@hide} */
-    @UnsupportedAppUsage
-    public ArraySet(Collection<E> set) {
+    /**
+     * Create a new ArraySet with items from the given collection.
+     */
+    public ArraySet(Collection<? extends E> set) {
         this();
         if (set != null) {
             addAll(set);