APIs to profile network usage for current UID.

Added startDataProfiling() and stopDataProfiling() to TrafficStats,
which can be used by apps to measure network usage delta between two
points in time.  Currently takes two NetworkStats snapshots and returns
delta, which will eventually include tag-level granularity.  Added
tests for NetworkStats delta subtraction.

Added NMS.getNetworkStatsUidDetail() that returns stats for specific
UID.  Always gives stats access for the calling UID, otherwise enforces
that caller has permission.  Fix readSingleLongFromFile(), since
/proc/ files don't have well-defined lengths.

Change-Id: Ic5b6414d8effbd66846e275b00d4b8a82c74589d

1 files changed, 97 insertions, 0 deletions

diff --git a/core/tests/coretests/src/android/net/NetworkStatsTest.java b/core/tests/coretests/src/android/net/NetworkStatsTest.java
new file mode 100644
index 0000000..45719c2
--- /dev/null
+++ b/core/tests/coretests/src/android/net/NetworkStatsTest.java
@@ -0,0 +1,97 @@
+/*
+ * Copyright (C) 2011 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package android.net;
+
+import android.os.SystemClock;
+import android.test.suitebuilder.annotation.SmallTest;
+
+import junit.framework.TestCase;
+
+@SmallTest
+public class NetworkStatsTest extends TestCase {
+
+    private static final String TEST_IFACE = "test0";
+
+    public void testFindIndex() throws Exception {
+        final NetworkStats stats = new NetworkStats.Builder(SystemClock.elapsedRealtime(), 3)
+                .addEntry(TEST_IFACE, 100, 1024, 0)
+                .addEntry(TEST_IFACE, 101, 0, 1024)
+                .addEntry(TEST_IFACE, 102, 1024, 1024).build();
+
+        assertEquals(2, stats.findIndex(TEST_IFACE, 102));
+        assertEquals(2, stats.findIndex(TEST_IFACE, 102));
+        assertEquals(0, stats.findIndex(TEST_IFACE, 100));
+        assertEquals(-1, stats.findIndex(TEST_IFACE, 6));
+    }
+
+    public void testSubtractIdenticalData() throws Exception {
+        final NetworkStats before = new NetworkStats.Builder(SystemClock.elapsedRealtime(), 2)
+                .addEntry(TEST_IFACE, 100, 1024, 0)
+                .addEntry(TEST_IFACE, 101, 0, 1024).build();
+
+        final NetworkStats after = new NetworkStats.Builder(SystemClock.elapsedRealtime(), 2)
+                .addEntry(TEST_IFACE, 100, 1024, 0)
+                .addEntry(TEST_IFACE, 101, 0, 1024).build();
+
+        final NetworkStats result = after.subtract(before);
+
+        assertEquals(0, result.rx[0]);
+        assertEquals(0, result.tx[0]);
+        assertEquals(0, result.rx[1]);
+        assertEquals(0, result.tx[1]);
+    }
+
+    public void testSubtractIdenticalRows() throws Exception {
+        final NetworkStats before = new NetworkStats.Builder(SystemClock.elapsedRealtime(), 2)
+                .addEntry(TEST_IFACE, 100, 1024, 0)
+                .addEntry(TEST_IFACE, 101, 0, 1024).build();
+
+        final NetworkStats after = new NetworkStats.Builder(SystemClock.elapsedRealtime(), 2)
+                .addEntry(TEST_IFACE, 100, 1025, 2)
+                .addEntry(TEST_IFACE, 101, 3, 1028).build();
+
+        final NetworkStats result = after.subtract(before);
+
+        // expect delta between measurements
+        assertEquals(1, result.rx[0]);
+        assertEquals(2, result.tx[0]);
+        assertEquals(3, result.rx[1]);
+        assertEquals(4, result.tx[1]);
+    }
+
+    public void testSubtractNewRows() throws Exception {
+        final NetworkStats before = new NetworkStats.Builder(SystemClock.elapsedRealtime(), 2)
+                .addEntry(TEST_IFACE, 100, 1024, 0)
+                .addEntry(TEST_IFACE, 101, 0, 1024).build();
+
+        final NetworkStats after = new NetworkStats.Builder(SystemClock.elapsedRealtime(), 3)
+                .addEntry(TEST_IFACE, 100, 1024, 0)
+                .addEntry(TEST_IFACE, 101, 0, 1024)
+                .addEntry(TEST_IFACE, 102, 1024, 1024).build();
+
+        final NetworkStats result = after.subtract(before);
+
+        // its okay to have new rows
+        assertEquals(0, result.rx[0]);
+        assertEquals(0, result.tx[0]);
+        assertEquals(0, result.rx[1]);
+        assertEquals(0, result.tx[1]);
+        assertEquals(1024, result.rx[2]);
+        assertEquals(1024, result.tx[2]);
+    }
+
+}