Data Usage public API

Added new API consisting of android.app.usage.NetworkUsageManager and
android.app.usage.NetworkUsageStats. Through them data usage on a
network interface can be programmatically queried. Both summary and
details are available.

Bug: 19208876
Change-Id: I0e0c4b37ae23ad1e589d4b0c955b93f28ba4333e
diff --git a/core/java/android/app/usage/NetworkStatsManager.java b/core/java/android/app/usage/NetworkStatsManager.java
new file mode 100644
index 0000000..af7c053
--- /dev/null
+++ b/core/java/android/app/usage/NetworkStatsManager.java
@@ -0,0 +1,233 @@
+/**
+ * Copyright (C) 2015 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.app.usage;
+
+import android.app.usage.NetworkUsageStats.Bucket;
+import android.content.Context;
+import android.net.ConnectivityManager;
+import android.net.NetworkIdentity;
+import android.net.NetworkTemplate;
+import android.os.RemoteException;
+import android.os.UserHandle;
+import android.util.Log;
+
+/**
+ * Provides access to network usage history and statistics. Usage data is collected in
+ * discrete bins of time called 'Buckets'. See {@link NetworkUsageStats.Bucket} for details.
+ * <p />
+ * Queries can define a time interval in the form of start and end timestamps (Long.MIN_VALUE and
+ * Long.MAX_VALUE can be used to simulate open ended intervals). All queries (except
+ * {@link #querySummaryForDevice}) collect only network usage of apps belonging to the same user
+ * as the client. In addition tethering usage, usage by removed users and apps, and usage by system
+ * is also included in the results.
+ * <h3>
+ * Summary queries
+ * </h3>
+ * These queries aggregate network usage across the whole interval. Therefore there will be only one
+ * bucket for a particular key and state combination. In case of the user-wide and device-wide
+ * summaries a single bucket containing the totalised network usage is returned.
+ * <h3>
+ * History queries
+ * </h3>
+ * These queries do not aggregate over time but do aggregate over state. Therefore there can be
+ * multiple buckets for a particular key but all Bucket's state is going to be
+ * {@link NetworkUsageStats.Bucket#STATE_ALL}.
+ * <p />
+ * <b>NOTE:</b> This API requires the permission
+ * {@link android.Manifest.permission#PACKAGE_USAGE_STATS}, which is a system-level permission and
+ * will not be granted to third-party apps. However, declaring the permission implies intention to
+ * use the API and the user of the device can grant permission through the Settings application.
+ * Profile owner apps are automatically granted permission to query data on the profile they manage
+ * (that is, for any query except {@link #querySummaryForDevice}). Device owner apps likewise get
+ * access to usage data of the primary user.
+ */
+public class NetworkStatsManager {
+    private final static String TAG = "NetworkStatsManager";
+
+    private final Context mContext;
+
+    /**
+     * {@hide}
+     */
+    public NetworkStatsManager(Context context) {
+        mContext = context;
+    }
+    /**
+     * Query network usage statistics summaries. Result is summarised data usage for the whole
+     * device. Result is a single Bucket aggregated over time, state and uid.
+     *
+     * @param networkType As defined in {@link ConnectivityManager}, e.g.
+     *            {@link ConnectivityManager#TYPE_MOBILE}, {@link ConnectivityManager#TYPE_WIFI}
+     *            etc.
+     * @param subscriberId If applicable, the subscriber id of the network interface.
+     * @param startTime Start of period. Defined in terms of "Unix time", see
+     *            {@link java.lang.System#currentTimeMillis}.
+     * @param endTime End of period. Defined in terms of "Unix time", see
+     *            {@link java.lang.System#currentTimeMillis}.
+     * @return Bucket object or null if permissions are insufficient or error happened during
+     *         statistics collection.
+     */
+    public Bucket querySummaryForDevice(int networkType, String subscriberId,
+            long startTime, long endTime) throws SecurityException, RemoteException {
+        NetworkTemplate template = createTemplate(networkType, subscriberId);
+        if (template == null) {
+            return null;
+        }
+
+        Bucket bucket = null;
+        NetworkUsageStats stats = new NetworkUsageStats(mContext, template, startTime, endTime);
+        bucket = stats.getDeviceSummaryForNetwork(startTime, endTime);
+
+        stats.close();
+        return bucket;
+    }
+
+    /**
+     * Query network usage statistics summaries. Result is summarised data usage for all uids
+     * belonging to calling user. Result is a single Bucket aggregated over time, state and uid.
+     *
+     * @param networkType As defined in {@link ConnectivityManager}, e.g.
+     *            {@link ConnectivityManager#TYPE_MOBILE}, {@link ConnectivityManager#TYPE_WIFI}
+     *            etc.
+     * @param subscriberId If applicable, the subscriber id of the network interface.
+     * @param startTime Start of period. Defined in terms of "Unix time", see
+     *            {@link java.lang.System#currentTimeMillis}.
+     * @param endTime End of period. Defined in terms of "Unix time", see
+     *            {@link java.lang.System#currentTimeMillis}.
+     * @return Bucket object or null if permissions are insufficient or error happened during
+     *         statistics collection.
+     */
+    public Bucket querySummaryForUser(int networkType, String subscriberId, long startTime,
+            long endTime) throws SecurityException, RemoteException {
+        NetworkTemplate template = createTemplate(networkType, subscriberId);
+        if (template == null) {
+            return null;
+        }
+
+        NetworkUsageStats stats;
+        stats = new NetworkUsageStats(mContext, template, startTime, endTime);
+        stats.startSummaryEnumeration(startTime, endTime);
+
+        stats.close();
+        return stats.getSummaryAggregate();
+    }
+
+    /**
+     * Query network usage statistics summaries. Result filtered to include only uids belonging to
+     * calling user. Result is aggregated over time, hence all buckets will have the same start and
+     * end timestamps. Not aggregated over state or uid.
+     *
+     * @param networkType As defined in {@link ConnectivityManager}, e.g.
+     *            {@link ConnectivityManager#TYPE_MOBILE}, {@link ConnectivityManager#TYPE_WIFI}
+     *            etc.
+     * @param subscriberId If applicable, the subscriber id of the network interface.
+     * @param startTime Start of period. Defined in terms of "Unix time", see
+     *            {@link java.lang.System#currentTimeMillis}.
+     * @param endTime End of period. Defined in terms of "Unix time", see
+     *            {@link java.lang.System#currentTimeMillis}.
+     * @return Statistics object or null if permissions are insufficient or error happened during
+     *         statistics collection.
+     */
+    public NetworkUsageStats querySummary(int networkType, String subscriberId, long startTime,
+            long endTime) throws SecurityException, RemoteException {
+        NetworkTemplate template = createTemplate(networkType, subscriberId);
+        if (template == null) {
+            return null;
+        }
+
+        NetworkUsageStats result;
+        result = new NetworkUsageStats(mContext, template, startTime, endTime);
+        result.startSummaryEnumeration(startTime, endTime);
+
+        return result;
+    }
+
+    /**
+     * Query network usage statistics details. Only usable for uids belonging to calling user.
+     * Result is aggregated over state but not aggregated over time.
+     *
+     * @param networkType As defined in {@link ConnectivityManager}, e.g.
+     *            {@link ConnectivityManager#TYPE_MOBILE}, {@link ConnectivityManager#TYPE_WIFI}
+     *            etc.
+     * @param subscriberId If applicable, the subscriber id of the network interface.
+     * @param startTime Start of period. Defined in terms of "Unix time", see
+     *            {@link java.lang.System#currentTimeMillis}.
+     * @param endTime End of period. Defined in terms of "Unix time", see
+     *            {@link java.lang.System#currentTimeMillis}.
+     * @param uid UID of app
+     * @return Statistics object or null if permissions are insufficient or error happened during
+     *         statistics collection.
+     */
+    public NetworkUsageStats queryDetailsForUid(int networkType, String subscriberId,
+            long startTime, long endTime, int uid) throws SecurityException, RemoteException {
+        NetworkTemplate template = createTemplate(networkType, subscriberId);
+        if (template == null) {
+            return null;
+        }
+
+        NetworkUsageStats result;
+        result = new NetworkUsageStats(mContext, template, startTime, endTime);
+        result.startHistoryEnumeration(uid);
+
+        return result;
+    }
+
+    /**
+     * Query network usage statistics details. Result filtered to include only uids belonging to
+     * calling user. Result is aggregated over state but not aggregated over time or uid.
+     *
+     * @param networkType As defined in {@link ConnectivityManager}, e.g.
+     *            {@link ConnectivityManager#TYPE_MOBILE}, {@link ConnectivityManager#TYPE_WIFI}
+     *            etc.
+     * @param subscriberId If applicable, the subscriber id of the network interface.
+     * @param startTime Start of period. Defined in terms of "Unix time", see
+     *            {@link java.lang.System#currentTimeMillis}.
+     * @param endTime End of period. Defined in terms of "Unix time", see
+     *            {@link java.lang.System#currentTimeMillis}.
+     * @return Statistics object or null if permissions are insufficient or error happened during
+     *         statistics collection.
+     */
+    public NetworkUsageStats queryDetails(int networkType, String subscriberId, long startTime,
+            long endTime) throws SecurityException, RemoteException {
+        NetworkTemplate template = createTemplate(networkType, subscriberId);
+        if (template == null) {
+            return null;
+        }
+        NetworkUsageStats result;
+        result = new NetworkUsageStats(mContext, template, startTime, endTime);
+        result.startUserUidEnumeration();
+        return result;
+    }
+
+    private static NetworkTemplate createTemplate(int networkType, String subscriberId) {
+        NetworkTemplate template = null;
+        switch (networkType) {
+            case ConnectivityManager.TYPE_MOBILE: {
+                template = NetworkTemplate.buildTemplateMobileAll(subscriberId);
+                } break;
+            case ConnectivityManager.TYPE_WIFI: {
+                template = NetworkTemplate.buildTemplateWifiWildcard();
+                } break;
+            default: {
+                Log.w(TAG, "Cannot create template for network type " + networkType
+                        + ", subscriberId '" + NetworkIdentity.scrubSubscriberId(subscriberId) +
+                        "'.");
+            }
+        }
+        return template;
+    }
+}