NetworkStats always needs arrays.

Internal logic relies on Arrays.copyOf(), so always give ourselves
valid arrays, using shared empty objects to save overhead.

Bug: 17502649
Change-Id: I5dbb00545bdfe45bbd48144ab505ea08cc92cbcd

2 files changed, 21 insertions, 0 deletions

diff --git a/core/java/android/net/NetworkStats.java b/core/java/android/net/NetworkStats.java
index 54d43d3..ea5dfd1 100644
--- a/core/java/android/net/NetworkStats.java
+++ b/core/java/android/net/NetworkStats.java
@@ -24,6 +24,8 @@ import android.util.SparseBooleanArray;
 import com.android.internal.annotations.VisibleForTesting;
 import com.android.internal.util.ArrayUtils;
 
+import libcore.util.EmptyArray;
+
 import java.io.CharArrayWriter;
 import java.io.PrintWriter;
 import java.util.Arrays;
@@ -169,6 +171,15 @@ public class NetworkStats implements Parcelable {
         } else {
             // Special case for use by NetworkStatsFactory to start out *really* empty.
             this.capacity = 0;
+            this.iface = EmptyArray.STRING;
+            this.uid = EmptyArray.INT;
+            this.set = EmptyArray.INT;
+            this.tag = EmptyArray.INT;
+            this.rxBytes = EmptyArray.LONG;
+            this.rxPackets = EmptyArray.LONG;
+            this.txBytes = EmptyArray.LONG;
+            this.txPackets = EmptyArray.LONG;
+            this.operations = EmptyArray.LONG;
         }
     }
 
diff --git a/core/tests/coretests/src/android/net/NetworkStatsTest.java b/core/tests/coretests/src/android/net/NetworkStatsTest.java
index 6331964..9ee4e20 100644
--- a/core/tests/coretests/src/android/net/NetworkStatsTest.java
+++ b/core/tests/coretests/src/android/net/NetworkStatsTest.java
@@ -310,6 +310,16 @@ public class NetworkStatsTest extends TestCase {
         assertEquals(128L + 512L, clone.getTotalBytes());
     }
 
+    public void testAddWhenEmpty() throws Exception {
+        final NetworkStats red = new NetworkStats(TEST_START, -1);
+        final NetworkStats blue = new NetworkStats(TEST_START, 5)
+                .addValues(TEST_IFACE, 100, SET_DEFAULT, TAG_NONE, 128L, 8L, 0L, 2L, 20L)
+                .addValues(TEST_IFACE2, 100, SET_DEFAULT, TAG_NONE, 512L, 32L, 0L, 0L, 0L);
+
+        // We're mostly checking that we don't crash
+        red.combineAllValues(blue);
+    }
+
     private static void assertValues(NetworkStats stats, int index, String iface, int uid, int set,
             int tag, long rxBytes, long rxPackets, long txBytes, long txPackets, long operations) {
         final NetworkStats.Entry entry = stats.getValues(index, null);