1 /*
2  * Copyright (C) 2015 The Android Open Source Project
3  *
4  * Licensed under the Apache License, Version 2.0 (the "License");
5  * you may not use this file except in compliance with the License.
6  * You may obtain a copy of the License at
7  *
8  *      http://www.apache.org/licenses/LICENSE-2.0
9  *
10  * Unless required by applicable law or agreed to in writing, software
11  * distributed under the License is distributed on an "AS IS" BASIS,
12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13  * See the License for the specific language governing permissions and
14  * limitations under the License.
15  */
16 
17 package com.android.mtp;
18 
19 import android.annotation.NonNull;
20 import android.annotation.Nullable;
21 import android.app.Notification;
22 import android.app.Service;
23 import android.app.NotificationManager;
24 import android.content.Intent;
25 import android.os.IBinder;
26 import android.os.Parcelable;
27 import android.service.notification.StatusBarNotification;
28 import android.util.Log;
29 import com.android.internal.util.Preconditions;
30 import java.util.HashSet;
31 import java.util.Set;
32 
33 /**
34  * Service to manage lifetime of DocumentsProvider's process.
35  * The service prevents the system from killing the process that holds USB connections. The service
36  * starts to run when the first MTP device is opened, and stops when the last MTP device is closed.
37  */
38 public class MtpDocumentsService extends Service {
39     static final String ACTION_UPDATE_NOTIFICATION = "com.android.mtp.UPDATE_NOTIFICATION";
40     static final String EXTRA_DEVICE_IDS = "deviceIds";
41     static final String EXTRA_DEVICE_NOTIFICATIONS = "deviceNotifications";
42 
43     private NotificationManager mNotificationManager;
44 
45     @Override
onBind(Intent intent)46     public IBinder onBind(Intent intent) {
47         // The service is used via intents.
48         return null;
49     }
50 
51     @Override
onCreate()52     public void onCreate() {
53         super.onCreate();
54         mNotificationManager = getSystemService(NotificationManager.class);
55     }
56 
57     @Override
onStartCommand(Intent intent, int flags, int startId)58     public int onStartCommand(Intent intent, int flags, int startId) {
59         // If intent is null, the service was restarted.
60         if (intent == null || ACTION_UPDATE_NOTIFICATION.equals(intent.getAction())) {
61             final int[] ids = intent.hasExtra(EXTRA_DEVICE_IDS) ?
62                     intent.getExtras().getIntArray(EXTRA_DEVICE_IDS) : null;
63             final Notification[] notifications = intent.hasExtra(EXTRA_DEVICE_NOTIFICATIONS) ?
64                     castToNotifications(intent.getExtras().getParcelableArray(
65                             EXTRA_DEVICE_NOTIFICATIONS)) : null;
66             return updateForegroundState(ids, notifications) ? START_STICKY : START_NOT_STICKY;
67         }
68         return START_NOT_STICKY;
69     }
70 
71     /**
72      * Updates the foreground state of the service.
73      * @return Whether the service is foreground or not.
74      */
updateForegroundState( @ullable int[] ids, @Nullable Notification[] notifications)75     private boolean updateForegroundState(
76             @Nullable int[] ids, @Nullable Notification[] notifications) {
77         final Set<Integer> openedNotification = new HashSet<>();
78         final int size = ids != null ? ids.length : 0;
79         if (size != 0) {
80             Preconditions.checkArgument(ids != null);
81             Preconditions.checkArgument(notifications != null);
82             Preconditions.checkArgument(ids.length == notifications.length);
83         }
84 
85         for (int i = 0; i < size; i++) {
86             if (i == 0) {
87                 // Mark this service as foreground with the notification so that the process is
88                 // not killed by the system while a MTP device is opened.
89                 startForeground(ids[i], notifications[i]);
90             } else {
91                 // Only one notification can be shown as a foreground notification. We need to
92                 // show the rest as normal notification.
93                 mNotificationManager.notify(ids[i], notifications[i]);
94             }
95             openedNotification.add(ids[i]);
96         }
97 
98         final StatusBarNotification[] activeNotifications =
99                 mNotificationManager.getActiveNotifications();
100         for (final StatusBarNotification notification : activeNotifications) {
101             if (!openedNotification.contains(notification.getId())) {
102                 mNotificationManager.cancel(notification.getId());
103             }
104         }
105 
106         if (size == 0) {
107             // There is no opened device.
108             stopForeground(true /* removeNotification */);
109             stopSelf();
110             return false;
111         }
112 
113         return true;
114     }
115 
castToNotifications(@onNull Parcelable[] src)116     private static @NonNull Notification[] castToNotifications(@NonNull Parcelable[] src) {
117         Preconditions.checkNotNull(src);
118         final Notification[] notifications = new Notification[src.length];
119         for (int i = 0; i < src.length; i++) {
120             notifications[i] = (Notification) src[i];
121         }
122         return notifications;
123     }
124 }
125