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      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.server.backup;
     18 
     19 import android.app.AlarmManager;
     20 import android.app.job.JobInfo;
     21 import android.app.job.JobParameters;
     22 import android.app.job.JobScheduler;
     23 import android.app.job.JobService;
     24 import android.content.ComponentName;
     25 import android.content.Context;
     26 import android.os.RemoteException;
     27 import android.util.Slog;
     28 
     29 import java.util.Random;
     30 
     31 /**
     32  * Job for scheduling key/value backup work.  This module encapsulates all
     33  * of the policy around when those backup passes are executed.
     34  */
     35 public class KeyValueBackupJob extends JobService {
     36     private static final String TAG = "KeyValueBackupJob";
     37     private static ComponentName sKeyValueJobService =
     38             new ComponentName("android", KeyValueBackupJob.class.getName());
     39     private static final int JOB_ID = 0x5039;
     40 
     41     // Minimum wait time between backups even while we're on charger
     42     static final long BATCH_INTERVAL = 4 * AlarmManager.INTERVAL_HOUR;
     43 
     44     // Random variation in next-backup scheduling time to avoid server load spikes
     45     private static final int FUZZ_MILLIS = 10 * 60 * 1000;
     46 
     47     // Once someone asks for a backup, this is how long we hold off until we find
     48     // an on-charging opportunity.  If we hit this max latency we will run the operation
     49     // regardless.  Privileged callers can always trigger an immediate pass via
     50     // BackupManager.backupNow().
     51     private static final long MAX_DEFERRAL = AlarmManager.INTERVAL_DAY;
     52 
     53     private static boolean sScheduled = false;
     54     private static long sNextScheduled = 0;
     55 
     56     public static void schedule(Context ctx) {
     57         schedule(ctx, 0);
     58     }
     59 
     60     public static void schedule(Context ctx, long delay) {
     61         synchronized (KeyValueBackupJob.class) {
     62             if (!sScheduled) {
     63                 if (delay <= 0) {
     64                     delay = BATCH_INTERVAL + new Random().nextInt(FUZZ_MILLIS);
     65                 }
     66                 if (BackupManagerService.DEBUG_SCHEDULING) {
     67                     Slog.v(TAG, "Scheduling k/v pass in "
     68                             + (delay / 1000 / 60) + " minutes");
     69                 }
     70                 JobScheduler js = (JobScheduler) ctx.getSystemService(Context.JOB_SCHEDULER_SERVICE);
     71                 JobInfo.Builder builder = new JobInfo.Builder(JOB_ID, sKeyValueJobService)
     72                         .setMinimumLatency(delay)
     73                         .setRequiredNetworkType(JobInfo.NETWORK_TYPE_ANY)
     74                         .setRequiresCharging(true)
     75                         .setOverrideDeadline(MAX_DEFERRAL);
     76                 js.schedule(builder.build());
     77 
     78                 sNextScheduled = System.currentTimeMillis() + delay;
     79                 sScheduled = true;
     80             }
     81         }
     82     }
     83 
     84     public static void cancel(Context ctx) {
     85         synchronized (KeyValueBackupJob.class) {
     86             JobScheduler js = (JobScheduler) ctx.getSystemService(Context.JOB_SCHEDULER_SERVICE);
     87             js.cancel(JOB_ID);
     88             sNextScheduled = 0;
     89             sScheduled = false;
     90         }
     91     }
     92 
     93     public static long nextScheduled() {
     94         synchronized (KeyValueBackupJob.class) {
     95             return sNextScheduled;
     96         }
     97     }
     98 
     99     @Override
    100     public boolean onStartJob(JobParameters params) {
    101         synchronized (KeyValueBackupJob.class) {
    102             sNextScheduled = 0;
    103             sScheduled = false;
    104         }
    105 
    106         // Time to run a key/value backup!
    107         Trampoline service = BackupManagerService.getInstance();
    108         try {
    109             service.backupNow();
    110         } catch (RemoteException e) {}
    111 
    112         // This was just a trigger; ongoing wakelock management is done by the
    113         // rest of the backup system.
    114         return false;
    115     }
    116 
    117     @Override
    118     public boolean onStopJob(JobParameters params) {
    119         // Intentionally empty; the job starting was just a trigger
    120         return false;
    121     }
    122 
    123 }
    124