[WIFICOND][API] Replace capability BitSet by an int

The capability bit set is standard constrained - 16 bits and no more.
Can use a simpler/lighter int.

Per API council feedback.

Bug: 148680192
Test: atest android.net.wifi
Test: atest com.android.server.wifi
Change-Id: I47e8458d64f998da2e9743ad850687bc56a24cf6

api/system-current.txt

@@ -8199,7 +8199,7 @@ package android.net.wifi.wificond {
     ctor public NativeScanResult();
     method public int describeContents();
     method @NonNull public byte[] getBssid();
-    method @NonNull public java.util.BitSet getCapabilities();
+    method @NonNull public int getCapabilities();
     method public int getFrequencyMhz();
     method @NonNull public byte[] getInformationElements();
     method @NonNull public java.util.List<android.net.wifi.wificond.RadioChainInfo> getRadioChainInfos();

api/system-lint-baseline.txt

@@ -64,10 +64,6 @@ GenericException: android.service.autofill.augmented.FillWindow#finalize():
     
 
 
-HeavyBitSet: android.net.wifi.wificond.NativeScanResult#getCapabilities():
-    
-
-
 IntentBuilderName: android.content.Context#registerReceiverForAllUsers(android.content.BroadcastReceiver, android.content.IntentFilter, String, android.os.Handler):
     Methods creating an Intent should be named `create<Foo>Intent()`, was `registerReceiverForAllUsers`
 

wifi/java/android/net/wifi/wificond/NativeScanResult.java

@@ -24,7 +24,6 @@ import android.os.Parcelable;
 import com.android.internal.annotations.VisibleForTesting;
 
 import java.util.ArrayList;
-import java.util.BitSet;
 import java.util.List;
 
 /**
@@ -34,8 +33,6 @@ import java.util.List;
  */
 @SystemApi
 public final class NativeScanResult implements Parcelable {
-    private static final int CAPABILITY_SIZE = 16;
-
     /** @hide */
     @VisibleForTesting
     public byte[] ssid;
@@ -56,7 +53,7 @@ public final class NativeScanResult implements Parcelable {
     public long tsf;
     /** @hide */
     @VisibleForTesting
-    public BitSet capability;
+    public int capability;
     /** @hide */
     @VisibleForTesting
     public boolean associated;
@@ -134,7 +131,7 @@ public final class NativeScanResult implements Parcelable {
      *  Returns the capabilities of the AP repseresented by this scan result as advertised in the
      *  received probe response or beacon.
      *
-     *  This is a bit mask describing the capabilities of a BSS. See IEEE Std 802.11: 8.4.1.4:
+     *  This is a bit mask describing the capabilities of a BSS. See IEEE Std 802.11: 9.4.1.4:
      *    Bit 0 - ESS
      *    Bit 1 - IBSS
      *    Bit 2 - CF Pollable
@@ -143,7 +140,7 @@ public final class NativeScanResult implements Parcelable {
      *    Bit 5 - Short Preamble
      *    Bit 6 - PBCC
      *    Bit 7 - Channel Agility
-     *    Bit 8 - Spectrum Mgmt
+     *    Bit 8 - Spectrum Management
      *    Bit 9 - QoS
      *    Bit 10 - Short Slot Time
      *    Bit 11 - APSD
@@ -154,7 +151,7 @@ public final class NativeScanResult implements Parcelable {
      *
      * @return a bit mask of capabilities.
      */
-    @NonNull public BitSet getCapabilities() {
+    @NonNull public int getCapabilities() {
         return capability;
     }
 
@@ -188,13 +185,7 @@ public final class NativeScanResult implements Parcelable {
         out.writeInt(frequency);
         out.writeInt(signalMbm);
         out.writeLong(tsf);
-        int capabilityInt = 0;
-        for (int i = 0; i < CAPABILITY_SIZE; i++) {
-            if (capability.get(i)) {
-                capabilityInt |= 1 << i;
-            }
-        }
-        out.writeInt(capabilityInt);
+        out.writeInt(capability);
         out.writeInt(associated ? 1 : 0);
         out.writeTypedList(radioChainInfos);
     }
@@ -220,13 +211,7 @@ public final class NativeScanResult implements Parcelable {
             result.frequency = in.readInt();
             result.signalMbm = in.readInt();
             result.tsf = in.readLong();
-            int capabilityInt = in.readInt();
-            result.capability = new BitSet(CAPABILITY_SIZE);
-            for (int i = 0; i < CAPABILITY_SIZE; i++) {
-                if ((capabilityInt & (1 << i)) != 0) {
-                    result.capability.set(i);
-                }
-            }
+            result.capability = in.readInt();
             result.associated = (in.readInt() != 0);
             result.radioChainInfos = new ArrayList<>();
             in.readTypedList(result.radioChainInfos, RadioChainInfo.CREATOR);

wifi/tests/src/android/net/wifi/wificond/NativeScanResultTest.java

@@ -28,7 +28,6 @@ import org.junit.Test;
 
 import java.util.ArrayList;
 import java.util.Arrays;
-import java.util.BitSet;
 
 /**
  * Unit tests for {@link android.net.wifi.wificond.NativeScanResult}.
@@ -46,7 +45,7 @@ public class NativeScanResultTest {
     private static final int TEST_FREQUENCY = 2456;
     private static final int TEST_SIGNAL_MBM = -45;
     private static final long TEST_TSF = 34455441;
-    private static final BitSet TEST_CAPABILITY = new BitSet(16) {{ set(2); set(5); }};
+    private static final int TEST_CAPABILITY = (0x1 << 2) | (0x1 << 5);
     private static final boolean TEST_ASSOCIATED = true;
     private static final int[] RADIO_CHAIN_IDS = { 0, 1 };
     private static final int[] RADIO_CHAIN_LEVELS = { -56, -65 };