Reduce unecessary allocation churn in MdnsServiceTypeClient.processResponse

Bug: 413371501
Test: atest ConnectivityCoverageTests:android.net.connectivity.com.android.server.connectivity.mdns.MdnsServiceTypeClientTests
Test: atest ConnectivityCoverageTests:android.net.connectivity.com.android.net.module.util.CollectionUtilsTest
Flag: EXEMPT bugfix

Change-Id: Id9abf0b79f6db155e6895b0dd7661d0aafb6b0a7

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

@@ -298,6 +298,11 @@ public class MdnsResponse {
         return new LinkedList<>(records);
     }
 
+    /** Gets the number of records. */
+    synchronized int getNumRecords() {
+        return records.size();
+    }
+
     /**
      * Drop address records if they are for a hostname that does not match the service record.
      *

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

@@ -265,7 +265,7 @@ public class MdnsResponseDecoder {
         for (int i = 0; i < augmentedToOriginal.size(); i++) {
             final MdnsResponse augmented = augmentedToOriginal.keyAt(i);
             final MdnsResponse original = augmentedToOriginal.valueAt(i);
-            if (augmented.getRecords().size() != original.getRecords().size()) {
+            if (augmented.getNumRecords() != original.getNumRecords()) {
                 modified.add(augmented);
             }
         }
@@ -304,4 +304,4 @@ public class MdnsResponseDecoder {
         }
         return result == null ? List.of() : result;
     }
-}
+}

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

@@ -59,14 +59,22 @@ public class MdnsServiceCache {
     public static class CacheKey {
         @NonNull final String mUpperCaseServiceType;
         @NonNull final SocketKey mSocketKey;
+        private final int mHashCode;
 
         CacheKey(@NonNull String serviceType, @NonNull SocketKey socketKey) {
             mUpperCaseServiceType = toDnsUpperCase(serviceType);
             mSocketKey = socketKey;
+
+            // Equivalent to Objects.hash(mUpperCaseServiceType, mSocketKey),
+            // but without the unnecessary array allocation.
+            int hashCode = 1;
+            hashCode = 31 * hashCode + mUpperCaseServiceType.hashCode();
+            hashCode = 31 * hashCode + mSocketKey.hashCode();
+            mHashCode = hashCode;
         }
 
         @Override public int hashCode() {
-            return Objects.hash(mUpperCaseServiceType, mSocketKey);
+            return mHashCode;
         }
 
         @Override public boolean equals(Object other) {
@@ -180,7 +188,8 @@ public class MdnsServiceCache {
      */
     public static MdnsResponse findMatchedResponse(@NonNull List<MdnsResponse> responses,
             @NonNull String serviceName) {
-        for (MdnsResponse response : responses) {
+        for (int i = 0; i < responses.size(); ++i) {
+            MdnsResponse response = responses.get(i);
             if (equalsIgnoreDnsCase(serviceName, response.getServiceInstanceName())) {
                 return response;
             }
@@ -190,7 +199,8 @@ public class MdnsServiceCache {
 
     private static CachedService findMatchedCachedService(
             @NonNull List<CachedService> cachedServices, @NonNull String serviceName) {
-        for (CachedService cachedService : cachedServices) {
+        for (int i = 0; i < cachedServices.size(); ++i) {
+            CachedService cachedService = cachedServices.get(i);
             if (equalsIgnoreDnsCase(serviceName, cachedService.mService.getServiceInstanceName())) {
                 return cachedService;
             }

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

@@ -40,6 +40,7 @@ public class SocketKey {
      */
     @NonNull
     private final String mInterfaceName;
+    private final int mHashCode;
 
     SocketKey(int interfaceIndex, @NonNull String interfaceName) {
         this(null /* network */, interfaceIndex, interfaceName);
@@ -49,6 +50,13 @@ public class SocketKey {
         mNetwork = network;
         mInterfaceIndex = interfaceIndex;
         mInterfaceName = interfaceName;
+
+        // Equivalent to Objects.hash(mNetwork, mInterfaceIndex), but without
+        // the unnecessary array allocation.
+        int hashCode = 1;
+        hashCode = 31 * hashCode + (mNetwork == null ? 0 : mNetwork.hashCode());
+        hashCode = 31 * hashCode + Integer.hashCode(mInterfaceIndex);
+        mHashCode = hashCode;
     }
 
     @Nullable
@@ -67,7 +75,7 @@ public class SocketKey {
 
     @Override
     public int hashCode() {
-        return Objects.hash(mNetwork, mInterfaceIndex);
+        return mHashCode;
     }
 
     @Override

staticlibs/framework/com/android/net/module/util/CollectionUtils.java

@@ -113,6 +113,16 @@ public final class CollectionUtils {
         return indexOf(elem, predicate) >= 0;
     }
 
+    /**
+     * @return True if any element satisfies the predicate, false otherwise.
+     *   Note that means this always returns false for empty collections.
+     *
+     * This is an overload for List that avoids unnecessary iterator allocation.
+     */
+    public static <T> boolean any(@NonNull List<T> elem, @NonNull Predicate<T> predicate) {
+        return indexOf(elem, predicate) >= 0;
+    }
+
     /**
      * @return The index of the first element that matches the predicate, or -1 if none.
      */
@@ -126,6 +136,21 @@ public final class CollectionUtils {
         return -1;
     }
 
+    /**
+     * @return The index of the first element that matches the predicate, or -1 if none.
+     *
+     * This is an overload for List that avoids unnecessary iterator allocation.
+     */
+    public static <T> int indexOf(@NonNull final List<T> elem,
+            @NonNull final Predicate<? super T> predicate) {
+        for (int idx = 0; idx < elem.size(); ++idx) {
+            if (predicate.test(elem.get(idx))) {
+                return idx;
+            }
+        }
+        return -1;
+    }
+
     /**
      * @return True if there exists at least one element in the sparse array for which
      * condition {@code predicate}

staticlibs/tests/unit/src/com/android/net/module/util/CollectionUtilsTest.kt

@@ -53,6 +53,12 @@ class CollectionUtilsTest {
         assertEquals(1, CollectionUtils.indexOf(listOf("AA", "BBB", "CCCC")) { it.length >= 3 })
         assertEquals(1, CollectionUtils.indexOf(listOf("AA", null, "CCCC")) { it == null })
         assertEquals(1, CollectionUtils.indexOf(listOf(null, "CCCC")) { it != null })
+
+        assertEquals(4, CollectionUtils.indexOf(setOf("A", "B", "C", "D", "E")) { it == "E" })
+        assertEquals(0, CollectionUtils.indexOf(setOf("A", "B", "C", "D", "E")) { it == "A" })
+        assertEquals(1, CollectionUtils.indexOf(setOf("AA", "BBB", "CCCC")) { it.length >= 3 })
+        assertEquals(1, CollectionUtils.indexOf(setOf("AA", null, "CCCC")) { it == null })
+        assertEquals(1, CollectionUtils.indexOf(setOf(null, "CCCC")) { it != null })
     }
 
     @Test