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      1 /*
      2  * Copyright (C) 2017 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 android.app.usage;
     18 
     19 import android.annotation.SystemApi;
     20 import android.app.Service;
     21 import android.app.usage.ICacheQuotaService;
     22 import android.content.Intent;
     23 import android.os.Bundle;
     24 import android.os.Handler;
     25 import android.os.IBinder;
     26 import android.os.Looper;
     27 import android.os.Message;
     28 import android.os.RemoteCallback;
     29 import android.util.Log;
     30 import android.util.Pair;
     31 
     32 import java.util.List;
     33 
     34 /**
     35  * CacheQuoteService defines a service which accepts cache quota requests and processes them,
     36  * thereby filling out how much quota each request deserves.
     37  * {@hide}
     38  */
     39 @SystemApi
     40 public abstract class CacheQuotaService extends Service {
     41     private static final String TAG = "CacheQuotaService";
     42 
     43     /**
     44      * The {@link Intent} action that must be declared as handled by a service
     45      * in its manifest for the system to recognize it as a quota providing service.
     46      */
     47     public static final String SERVICE_INTERFACE = "android.app.usage.CacheQuotaService";
     48 
     49     /** {@hide} **/
     50     public static final String REQUEST_LIST_KEY = "requests";
     51 
     52     private CacheQuotaServiceWrapper mWrapper;
     53     private Handler mHandler;
     54 
     55     @Override
     56     public void onCreate() {
     57         super.onCreate();
     58         mWrapper = new CacheQuotaServiceWrapper();
     59         mHandler = new ServiceHandler(getMainLooper());
     60     }
     61 
     62     @Override
     63     public IBinder onBind(Intent intent) {
     64         return mWrapper;
     65     }
     66 
     67     /**
     68      * Processes the cache quota list upon receiving a list of requests.
     69      * @param requests A list of cache quotas to fulfill.
     70      * @return A completed list of cache quota requests.
     71      */
     72     public abstract List<CacheQuotaHint> onComputeCacheQuotaHints(
     73             List<CacheQuotaHint> requests);
     74 
     75     private final class CacheQuotaServiceWrapper extends ICacheQuotaService.Stub {
     76         @Override
     77         public void computeCacheQuotaHints(
     78                 RemoteCallback callback, List<CacheQuotaHint> requests) {
     79             final Pair<RemoteCallback, List<CacheQuotaHint>> pair =
     80                     Pair.create(callback, requests);
     81             Message msg = mHandler.obtainMessage(ServiceHandler.MSG_SEND_LIST, pair);
     82             mHandler.sendMessage(msg);
     83         }
     84     }
     85 
     86     private final class ServiceHandler extends Handler {
     87         public static final int MSG_SEND_LIST = 1;
     88 
     89         public ServiceHandler(Looper looper) {
     90             super(looper, null, true);
     91         }
     92 
     93         @Override
     94         public void handleMessage(Message msg) {
     95             final int action = msg.what;
     96             switch (action) {
     97                 case MSG_SEND_LIST:
     98                     final Pair<RemoteCallback, List<CacheQuotaHint>> pair =
     99                             (Pair<RemoteCallback, List<CacheQuotaHint>>) msg.obj;
    100                     List<CacheQuotaHint> processed = onComputeCacheQuotaHints(pair.second);
    101                     final Bundle data = new Bundle();
    102                     data.putParcelableList(REQUEST_LIST_KEY, processed);
    103 
    104                     final RemoteCallback callback = pair.first;
    105                     callback.sendResult(data);
    106                     break;
    107                 default:
    108                     Log.w(TAG, "Handling unknown message: " + action);
    109             }
    110         }
    111     }
    112 }
    113