Use addEntries when creating NetworkStats

In the current design, NetworkStats.addEntry is used within a
loop to create a NetworkStats instance from entries. This results
in a large memory footprint because the addEntry() method clones
the original NetworkStats instance each time it is called.

This change utilizes the newly created API to add a list of
entries at once. This approach only clones the instance once,
thereby reducing the required memory footprint.

Test: atest NetworkStaticLibTests:com.android.net.moduletests.util.NetworkStatsUtilsTest#testPublicStatsToAndroidNetStats
Test: atest ConnectivityCoverageTests:android.net.connectivity.com.android.net.module.util.NetworkStatsUtilsTest
      (on S device)
Test: atest ConnectivityCoverageTests:com.android.testutils.NetworkStatsUtilsTest
      (on S device)
Bug: 335680025
Change-Id: I5c635613ed3ba34d840ee71b6bef21d10105df0d
diff --git a/staticlibs/Android.bp b/staticlibs/Android.bp
index ed0670d..94a2411 100644
--- a/staticlibs/Android.bp
+++ b/staticlibs/Android.bp
@@ -296,6 +296,9 @@
         "framework-connectivity-t.stubs.module_lib",
         "framework-location.stubs.module_lib",
     ],
+    static_libs: [
+        "modules-utils-build",
+    ],
     jarjar_rules: "jarjar-rules-shared.txt",
     visibility: [
         "//cts/tests/tests/net",
diff --git a/staticlibs/framework/com/android/net/module/util/NetworkStatsUtils.java b/staticlibs/framework/com/android/net/module/util/NetworkStatsUtils.java
index 41a9428..04b6174 100644
--- a/staticlibs/framework/com/android/net/module/util/NetworkStatsUtils.java
+++ b/staticlibs/framework/com/android/net/module/util/NetworkStatsUtils.java
@@ -19,6 +19,9 @@
 import android.app.usage.NetworkStats;
 
 import com.android.internal.annotations.VisibleForTesting;
+import com.android.modules.utils.build.SdkLevel;
+
+import java.util.ArrayList;
 
 /**
  * Various utilities used for NetworkStats related code.
@@ -105,12 +108,21 @@
      */
     public static android.net.NetworkStats fromPublicNetworkStats(
             NetworkStats publiceNetworkStats) {
-        android.net.NetworkStats stats = new android.net.NetworkStats(0L, 0);
+        final ArrayList<android.net.NetworkStats.Entry> entries = new ArrayList<>();
         while (publiceNetworkStats.hasNextBucket()) {
             NetworkStats.Bucket bucket = new NetworkStats.Bucket();
             publiceNetworkStats.getNextBucket(bucket);
-            final android.net.NetworkStats.Entry entry = fromBucket(bucket);
-            stats = stats.addEntry(entry);
+            entries.add(fromBucket(bucket));
+        }
+        android.net.NetworkStats stats = new android.net.NetworkStats(0L, 0);
+        // The new API is only supported on devices running the mainline version of `NetworkStats`.
+        // It should always be used when available for memory efficiency.
+        if (SdkLevel.isAtLeastT()) {
+            stats = stats.addEntries(entries);
+        } else {
+            for (android.net.NetworkStats.Entry entry : entries) {
+                stats = stats.addEntry(entry);
+            }
         }
         return stats;
     }
diff --git a/staticlibs/tests/unit/src/com/android/net/module/util/NetworkStatsUtilsTest.kt b/staticlibs/tests/unit/src/com/android/net/module/util/NetworkStatsUtilsTest.kt
index baadad0..97d3c19 100644
--- a/staticlibs/tests/unit/src/com/android/net/module/util/NetworkStatsUtilsTest.kt
+++ b/staticlibs/tests/unit/src/com/android/net/module/util/NetworkStatsUtilsTest.kt
@@ -17,15 +17,27 @@
 package com.android.net.module.util
 
 import android.net.NetworkStats
+import android.net.NetworkStats.DEFAULT_NETWORK_NO
+import android.net.NetworkStats.DEFAULT_NETWORK_YES
+import android.net.NetworkStats.Entry
+import android.net.NetworkStats.METERED_NO
+import android.net.NetworkStats.ROAMING_NO
+import android.net.NetworkStats.ROAMING_YES
+import android.net.NetworkStats.SET_DEFAULT
+import android.net.NetworkStats.TAG_NONE
 import androidx.test.filters.SmallTest
 import androidx.test.runner.AndroidJUnit4
 import com.android.testutils.assertEntryEquals
+import com.android.testutils.assertNetworkStatsEquals
+import com.android.testutils.makePublicStatsFromAndroidNetStats
 import kotlin.test.assertEquals
 import kotlin.test.assertFailsWith
 import org.junit.Test
 import org.junit.runner.RunWith
 import org.mockito.Mockito.doReturn
 import org.mockito.Mockito.mock
+import org.mockito.Mockito.`when`
+
 
 @RunWith(AndroidJUnit4::class)
 @SmallTest
@@ -93,6 +105,37 @@
         assertEntryEquals(expectedEntry, entry)
     }
 
+    @Test
+    fun testPublicStatsToAndroidNetStats() {
+        val uid1 = 10001
+        val uid2 = 10002
+        val testIface = "wlan0"
+        val testAndroidNetStats = NetworkStats(0L, 3)
+                .addEntry(Entry(testIface, uid1, SET_DEFAULT, TAG_NONE,
+                        METERED_NO, ROAMING_NO, DEFAULT_NETWORK_YES, 20, 3, 57, 40, 3))
+                .addEntry(Entry(
+                        testIface, uid2, SET_DEFAULT, TAG_NONE,
+                        METERED_NO, ROAMING_YES, DEFAULT_NETWORK_NO, 2, 7, 2, 5, 7))
+                .addEntry(Entry(testIface, uid2, SET_DEFAULT, TAG_NONE,
+                        METERED_NO, ROAMING_YES, DEFAULT_NETWORK_NO, 4, 5, 3, 1, 8))
+        val publicStats: android.app.usage.NetworkStats =
+                makePublicStatsFromAndroidNetStats(testAndroidNetStats)
+        val androidNetStats: NetworkStats =
+                NetworkStatsUtils.fromPublicNetworkStats(publicStats)
+
+        // 1. The public `NetworkStats` class does not include interface information.
+        //    Interface details must be removed and items with duplicated
+        //    keys need to be merged before making any comparisons.
+        // 2. The public `NetworkStats` class lacks an operations field.
+        //    Thus, the information will not be preserved during the conversion.
+        val expectedStats = NetworkStats(0L, 2)
+                .addEntry(Entry(null, uid1, SET_DEFAULT, TAG_NONE,
+                        METERED_NO, ROAMING_NO, DEFAULT_NETWORK_YES, 20, 3, 57, 40, 0))
+                .addEntry(Entry(null, uid2, SET_DEFAULT, TAG_NONE,
+                        METERED_NO, ROAMING_YES, DEFAULT_NETWORK_NO, 6, 12, 5, 6, 0))
+        assertNetworkStatsEquals(expectedStats, androidNetStats)
+    }
+
     private fun makeMockBucket(
         uid: Int,
         tag: Int,
diff --git a/staticlibs/testutils/devicetests/com/android/testutils/NetworkStatsUtils.kt b/staticlibs/testutils/devicetests/com/android/testutils/NetworkStatsUtils.kt
index f2b14f5..e8c7297 100644
--- a/staticlibs/testutils/devicetests/com/android/testutils/NetworkStatsUtils.kt
+++ b/staticlibs/testutils/devicetests/com/android/testutils/NetworkStatsUtils.kt
@@ -16,7 +16,12 @@
 
 package com.android.testutils
 
+import android.app.usage.NetworkStatsManager
+import android.content.Context
+import android.net.INetworkStatsService
+import android.net.INetworkStatsSession
 import android.net.NetworkStats
+import android.net.NetworkTemplate
 import android.text.TextUtils
 import com.android.modules.utils.build.SdkLevel
 import kotlin.test.assertTrue
@@ -112,3 +117,32 @@
 fun assertParcelingIsLossless(stats: NetworkStats) {
     assertParcelingIsLossless(stats) { a, b -> orderInsensitiveEquals(a, b) }
 }
+
+/**
+ * Make a {@link android.app.usage.NetworkStats} instance from
+ * a {@link android.net.NetworkStats} instance.
+ */
+// It's not possible to directly create a mocked `NetworkStats` instance
+// because of limitations with `NetworkStats#getNextBucket`.
+// As a workaround for testing, create a mock by controlling the return values
+// from the mocked service that provides the `NetworkStats` data.
+// Notes:
+//   1. The order of records in the final `NetworkStats` object might change or
+//      some records might be merged if there are items with duplicate keys.
+//   2. The interface and operations fields will be empty since there is
+//      no such field in the {@link android.app.usage.NetworkStats}.
+fun makePublicStatsFromAndroidNetStats(androidNetStats: NetworkStats):
+        android.app.usage.NetworkStats {
+    val mockService = Mockito.mock(INetworkStatsService::class.java)
+    val manager = NetworkStatsManager(Mockito.mock(Context::class.java), mockService)
+    val mockStatsSession = Mockito.mock(INetworkStatsSession::class.java)
+
+    Mockito.doReturn(mockStatsSession).`when`(mockService)
+            .openSessionForUsageStats(anyInt(), any())
+    Mockito.doReturn(androidNetStats).`when`(mockStatsSession).getSummaryForAllUid(
+            any(NetworkTemplate::class.java), anyLong(), anyLong(), anyBoolean())
+    return manager.querySummary(
+            Mockito.mock(NetworkTemplate::class.java),
+            Long.MIN_VALUE, Long.MAX_VALUE
+    )
+}