Return NetworkStats bundle from NM service.

Introduce NetworkStats which is a collection of network statistics,
which should match the structure communicated by kernel module through
netd.  Will introduce tags and fg/bg stats later.  Kept entirely in a
flat data structure to optimize parcel speed.

Initial pass at returning NetworkStats from NetworkManagementService,
both summary and details.  Will eventually pull data from kernel module
over netd connection.

Change-Id: I92d9f61678ec8c22e2ce26775fb035a0cf32413f

core/java/android/net/NetworkStats.aidl

@@ -0,0 +1,19 @@
+/**
+ * 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;
+
+parcelable NetworkStats;

core/java/android/net/NetworkStats.java

@@ -0,0 +1,158 @@
+/*
+ * 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.Parcel;
+import android.os.Parcelable;
+import android.os.SystemClock;
+
+import java.io.CharArrayWriter;
+import java.io.PrintWriter;
+
+/**
+ * Collection of network statistics. Can contain summary details across all
+ * interfaces, or details with per-UID granularity. Designed to parcel quickly
+ * across process boundaries.
+ *
+ * @hide
+ */
+public class NetworkStats implements Parcelable {
+    /** {@link #iface} value when entry is summarized over all interfaces. */
+    public static final String IFACE_ALL = null;
+    /** {@link #uid} value when entry is summarized over all UIDs. */
+    public static final int UID_ALL = 0;
+
+    /**
+     * {@link SystemClock#elapsedRealtime()} timestamp when this data was
+     * generated.
+     */
+    public final long elapsedRealtime;
+    public final String[] iface;
+    public final int[] uid;
+    public final long[] rx;
+    public final long[] tx;
+
+    // TODO: add fg/bg stats and tag granularity
+
+    private NetworkStats(long elapsedRealtime, String[] iface, int[] uid, long[] rx, long[] tx) {
+        this.elapsedRealtime = elapsedRealtime;
+        this.iface = iface;
+        this.uid = uid;
+        this.rx = rx;
+        this.tx = tx;
+    }
+
+    public NetworkStats(Parcel parcel) {
+        elapsedRealtime = parcel.readLong();
+        iface = parcel.createStringArray();
+        uid = parcel.createIntArray();
+        rx = parcel.createLongArray();
+        tx = parcel.createLongArray();
+    }
+
+    public static class Builder {
+        private long mElapsedRealtime;
+        private final String[] mIface;
+        private final int[] mUid;
+        private final long[] mRx;
+        private final long[] mTx;
+
+        private int mIndex = 0;
+
+        public Builder(long elapsedRealtime, int size) {
+            mElapsedRealtime = elapsedRealtime;
+            mIface = new String[size];
+            mUid = new int[size];
+            mRx = new long[size];
+            mTx = new long[size];
+        }
+
+        public void addEntry(String iface, int uid, long rx, long tx) {
+            mIface[mIndex] = iface;
+            mUid[mIndex] = uid;
+            mRx[mIndex] = rx;
+            mTx[mIndex] = tx;
+            mIndex++;
+        }
+
+        public NetworkStats build() {
+            if (mIndex != mIface.length) {
+                throw new IllegalArgumentException("unexpected number of entries");
+            }
+            return new NetworkStats(mElapsedRealtime, mIface, mUid, mRx, mTx);
+        }
+    }
+
+    /**
+     * Find first stats index that matches the requested parameters.
+     */
+    public int findIndex(String iface, int uid) {
+        for (int i = 0; i < this.iface.length; i++) {
+            if (equal(iface, this.iface[i]) && uid == this.uid[i]) {
+                return i;
+            }
+        }
+        return -1;
+    }
+
+    private static boolean equal(Object a, Object b) {
+        return a == b || (a != null && a.equals(b));
+    }
+
+    /** {@inheritDoc} */
+    public int describeContents() {
+        return 0;
+    }
+
+    public void dump(String prefix, PrintWriter pw) {
+        pw.print(prefix);
+        pw.print("NetworkStats: elapsedRealtime="); pw.println(elapsedRealtime);
+        for (int i = 0; i < iface.length; i++) {
+            pw.print(prefix);
+            pw.print("  iface="); pw.print(iface[i]);
+            pw.print(" uid="); pw.print(uid[i]);
+            pw.print(" rx="); pw.print(rx[i]);
+            pw.print(" tx="); pw.println(tx[i]);
+        }
+    }
+
+    @Override
+    public String toString() {
+        final CharArrayWriter writer = new CharArrayWriter();
+        dump("", new PrintWriter(writer));
+        return writer.toString();
+    }
+
+    /** {@inheritDoc} */
+    public void writeToParcel(Parcel dest, int flags) {
+        dest.writeLong(elapsedRealtime);
+        dest.writeStringArray(iface);
+        dest.writeIntArray(uid);
+        dest.writeLongArray(rx);
+        dest.writeLongArray(tx);
+    }
+
+    public static final Creator<NetworkStats> CREATOR = new Creator<NetworkStats>() {
+        public NetworkStats createFromParcel(Parcel in) {
+            return new NetworkStats(in);
+        }
+
+        public NetworkStats[] newArray(int size) {
+            return new NetworkStats[size];
+        }
+    };
+}