From a60572f8441e5799da6d09f5ced03fa6ad42ed18 Mon Sep 17 00:00:00 2001
From: Yuyang Huang <yuyanghuang@google.com>
Date: Wed, 11 Dec 2024 19:48:56 +0900
Subject: [PATCH] Use CollectionUtils for array concatenation in NsdService

Simplified code in the NsdService by utilizing methods from
CollectionUtils for array concatenation. This change reduces code
duplication and improves maintainability.

Test: TH
Change-Id: I6d85f01047e7e70d0e1ea2fe397b703deeee6d0a
---
 .../connectivity/mdns/EnqueueMdnsQueryCallable.java  |  7 ++-----
 .../connectivity/mdns/MdnsRecordRepository.java      | 12 ++----------
 .../server/connectivity/mdns/util/MdnsUtils.java     |  8 +++-----
 3 files changed, 7 insertions(+), 20 deletions(-)

diff --git a/service-t/src/com/android/server/connectivity/mdns/EnqueueMdnsQueryCallable.java b/service-t/src/com/android/server/connectivity/mdns/EnqueueMdnsQueryCallable.java
index f55db93767..81ba53081e 100644
--- a/service-t/src/com/android/server/connectivity/mdns/EnqueueMdnsQueryCallable.java
+++ b/service-t/src/com/android/server/connectivity/mdns/EnqueueMdnsQueryCallable.java
@@ -139,11 +139,8 @@ public class EnqueueMdnsQueryCallable implements Callable<Pair<Integer, List<Str
                 // Base service type
                 questions.add(new MdnsPointerRecord(serviceTypeLabels, expectUnicastResponse));
                 for (String subtype : subtypes) {
-                    final String[] labels = new String[serviceTypeLabels.length + 2];
-                    labels[0] = MdnsConstants.SUBTYPE_PREFIX + subtype;
-                    labels[1] = MdnsConstants.SUBTYPE_LABEL;
-                    System.arraycopy(serviceTypeLabels, 0, labels, 2, serviceTypeLabels.length);
-
+                    final String[] labels = MdnsUtils.constructFullSubtype(serviceTypeLabels,
+                            MdnsConstants.SUBTYPE_PREFIX + subtype);
                     questions.add(new MdnsPointerRecord(labels, expectUnicastResponse));
                 }
             }
diff --git a/service-t/src/com/android/server/connectivity/mdns/MdnsRecordRepository.java b/service-t/src/com/android/server/connectivity/mdns/MdnsRecordRepository.java
index c3cb776b74..bfef5d9204 100644
--- a/service-t/src/com/android/server/connectivity/mdns/MdnsRecordRepository.java
+++ b/service-t/src/com/android/server/connectivity/mdns/MdnsRecordRepository.java
@@ -1482,22 +1482,14 @@ public class MdnsRecordRepository {
 
     private static String[] splitFullyQualifiedName(
             @NonNull NsdServiceInfo info, @NonNull String[] serviceType) {
-        final String[] split = new String[serviceType.length + 1];
-        split[0] = info.getServiceName();
-        System.arraycopy(serviceType, 0, split, 1, serviceType.length);
-
-        return split;
+        return CollectionUtils.prependArray(String.class, serviceType, info.getServiceName());
     }
 
     private static String[] splitServiceType(@NonNull NsdServiceInfo info) {
         // String.split(pattern, 0) removes trailing empty strings, which would appear when
         // splitting "domain.name." (with a dot a the end), so this is what is needed here.
         final String[] split = info.getServiceType().split("\\.", 0);
-        final String[] type = new String[split.length + 1];
-        System.arraycopy(split, 0, type, 0, split.length);
-        type[split.length] = LOCAL_TLD;
-
-        return type;
+        return CollectionUtils.appendArray(String.class, split, LOCAL_TLD);
     }
 
     /** Returns whether there will be an SRV record when registering the {@code info}. */
diff --git a/service-t/src/com/android/server/connectivity/mdns/util/MdnsUtils.java b/service-t/src/com/android/server/connectivity/mdns/util/MdnsUtils.java
index 41b15ddd24..282ca9ab5d 100644
--- a/service-t/src/com/android/server/connectivity/mdns/util/MdnsUtils.java
+++ b/service-t/src/com/android/server/connectivity/mdns/util/MdnsUtils.java
@@ -28,6 +28,7 @@ import android.os.SystemClock;
 import android.util.ArraySet;
 import android.util.Pair;
 
+import com.android.net.module.util.CollectionUtils;
 import com.android.server.connectivity.mdns.MdnsConstants;
 import com.android.server.connectivity.mdns.MdnsInetAddressRecord;
 import com.android.server.connectivity.mdns.MdnsPacket;
@@ -273,11 +274,8 @@ public class MdnsUtils {
      * of ["_printer", "_sub", "_http", "_tcp"].
      */
     public static String[] constructFullSubtype(String[] serviceType, String subtype) {
-        String[] fullSubtype = new String[serviceType.length + 2];
-        fullSubtype[0] = subtype;
-        fullSubtype[1] = MdnsConstants.SUBTYPE_LABEL;
-        System.arraycopy(serviceType, 0, fullSubtype, 2, serviceType.length);
-        return fullSubtype;
+        return CollectionUtils.prependArray(String.class, serviceType, subtype,
+                MdnsConstants.SUBTYPE_LABEL);
     }
 
     /** A wrapper class of {@link SystemClock} to be mocked in unit tests. */