Clear inetaddress fields when removing the record

When calling MdnsResponse.setInet4AddressRecord with null, the record
was removed from the records list, but not from the inet4AddressRecord /
inet6AddressRecord fields.

Fix that, and update the MdnsResponseDecoder test that missed the bug
because it modified the same incomplete MdnsResponse multiple times
(so isComplete keeps returning false), instead of using a copy of
a complete MdnsResponse.

This requires using a copy constructor, which will be useful for future
changes, so add it with a test.

Bug: 267570781
Test: atest
Change-Id: I199a8e4bc9a54a142c1fec1acee2ab6b1baa7efb

service-t/src/com/android/server/connectivity/mdns/MdnsResponse.java

@@ -16,12 +16,14 @@
 
 package com.android.server.connectivity.mdns;
 
+import android.annotation.NonNull;
 import android.annotation.Nullable;
 import android.net.Network;
 
 import com.android.internal.annotations.VisibleForTesting;
 
 import java.io.IOException;
+import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.Iterator;
 import java.util.LinkedList;
@@ -48,6 +50,18 @@ public class MdnsResponse {
         this.network = network;
     }
 
+    public MdnsResponse(@NonNull MdnsResponse base) {
+        records = new ArrayList<>(base.records);
+        pointerRecords = new ArrayList<>(base.pointerRecords);
+        serviceRecord = base.serviceRecord;
+        textRecord = base.textRecord;
+        inet4AddressRecord = base.inet4AddressRecord;
+        inet6AddressRecord = base.inet6AddressRecord;
+        lastUpdateTime = base.lastUpdateTime;
+        interfaceIndex = base.interfaceIndex;
+        network = base.network;
+    }
+
     // This generic typed helper compares records for equality.
     // Returns True if records are the same.
     private <T> boolean recordsAreSame(T a, T b) {
@@ -178,6 +192,7 @@ public class MdnsResponse {
         }
         if (this.inet4AddressRecord != null) {
             records.remove(this.inet4AddressRecord);
+            this.inet4AddressRecord = null;
         }
         if (newInet4AddressRecord != null && newInet4AddressRecord.getInet4Address() != null) {
             this.inet4AddressRecord = newInet4AddressRecord;
@@ -203,6 +218,7 @@ public class MdnsResponse {
         }
         if (this.inet6AddressRecord != null) {
             records.remove(this.inet6AddressRecord);
+            this.inet6AddressRecord = null;
         }
         if (newInet6AddressRecord != null && newInet6AddressRecord.getInet6Address() != null) {
             this.inet6AddressRecord = newInet6AddressRecord;

tests/unit/java/com/android/server/connectivity/mdns/MdnsResponseDecoderTests.java

@@ -16,6 +16,8 @@
 
 package com.android.server.connectivity.mdns;
 
+import static android.net.InetAddresses.parseNumericAddress;
+
 import static com.android.server.connectivity.mdns.MdnsResponseDecoder.Clock;
 import static com.android.testutils.DevSdkIgnoreRuleKt.SC_V2;
 
@@ -239,25 +241,29 @@ public class MdnsResponseDecoderTests {
 
     @Test
     public void testIsComplete() {
-        MdnsResponse response = responses.get(0);
+        MdnsResponse response = new MdnsResponse(responses.get(0));
         assertTrue(response.isComplete());
 
         response.clearPointerRecords();
         assertFalse(response.isComplete());
 
-        response = responses.get(0);
+        response = new MdnsResponse(responses.get(0));
         response.setInet4AddressRecord(null);
         assertFalse(response.isComplete());
 
-        response = responses.get(0);
+        response.setInet6AddressRecord(new MdnsInetAddressRecord(new String[] { "testhostname" },
+                0L /* receiptTimeMillis */, false /* cacheFlush */, 1234L /* ttlMillis */,
+                parseNumericAddress("2008:db1::123")));
+        assertTrue(response.isComplete());
+
         response.setInet6AddressRecord(null);
         assertFalse(response.isComplete());
 
-        response = responses.get(0);
+        response = new MdnsResponse(responses.get(0));
         response.setServiceRecord(null);
         assertFalse(response.isComplete());
 
-        response = responses.get(0);
+        response = new MdnsResponse(responses.get(0));
         response.setTextRecord(null);
         assertFalse(response.isComplete());
     }

tests/unit/java/com/android/server/connectivity/mdns/MdnsResponseTests.java

@@ -16,6 +16,8 @@
 
 package com.android.server.connectivity.mdns;
 
+import static android.net.InetAddresses.parseNumericAddress;
+
 import static com.android.testutils.DevSdkIgnoreRuleKt.SC_V2;
 
 import static org.junit.Assert.assertEquals;
@@ -26,6 +28,8 @@ import static org.junit.Assert.assertTrue;
 import static org.junit.Assert.fail;
 import static org.mockito.Mockito.mock;
 
+import static java.util.Collections.emptyList;
+
 import android.net.Network;
 
 import com.android.net.module.util.HexDump;
@@ -330,4 +334,35 @@ public class MdnsResponseTests {
         // Merging should not indicate any change.
         assertFalse(response.mergeRecordsFrom(response2));
     }
+
+    @Test
+    public void copyConstructor() {
+        final MdnsResponse response = new MdnsResponse(/* now= */ 0, INTERFACE_INDEX, mNetwork);
+        final String[] hostname = new String[] { "MyHostname" };
+        final String[] serviceName = new String[] { "MyService", "_type", "_tcp", "local" };
+        final String[] serviceType = new String[] { "_type", "_tcp", "local" };
+        response.addPointerRecord(new MdnsPointerRecord(serviceType, 0L /* receiptTimeMillis */,
+                false /* cacheFlush */, 1234L /* ttlMillis */, serviceName));
+        response.setServiceRecord(new MdnsServiceRecord(serviceName, 0L /* receiptTimeMillis */,
+                true /* cacheFlush */, 1234L /* ttlMillis */, 0 /* servicePriority */,
+                0 /* serviceWeight */, 0 /* servicePort */, hostname));
+        response.setTextRecord(new MdnsTextRecord(serviceName, 0L /* receiptTimeMillis */,
+                true /* cacheFlush */, 1234L /* ttlMillis */, emptyList() /* entries */));
+        response.setInet4AddressRecord(new MdnsInetAddressRecord(
+                hostname, 0L /* receiptTimeMillis */, true /* cacheFlush */,
+                1234L /* ttlMillis */, parseNumericAddress("192.0.2.123")));
+        response.setInet6AddressRecord(new MdnsInetAddressRecord(
+                hostname, 0L /* receiptTimeMillis */, true /* cacheFlush */,
+                1234L /* ttlMillis */, parseNumericAddress("2001:db8::123")));
+        final MdnsResponse copy = new MdnsResponse(response);
+
+        assertEquals(response.getInet6AddressRecord(), copy.getInet6AddressRecord());
+        assertEquals(response.getInet4AddressRecord(), copy.getInet4AddressRecord());
+        assertEquals(response.getPointerRecords(), copy.getPointerRecords());
+        assertEquals(response.getServiceRecord(), copy.getServiceRecord());
+        assertEquals(response.getTextRecord(), copy.getTextRecord());
+        assertEquals(response.getRecords(), copy.getRecords());
+        assertEquals(response.getNetwork(), copy.getNetwork());
+        assertEquals(response.getInterfaceIndex(), copy.getInterfaceIndex());
+    }
 }