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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 package com.android.car.pm;
     17 
     18 import android.content.Context;
     19 import android.content.pm.ApplicationInfo;
     20 import android.content.pm.PackageManager;
     21 import android.content.pm.PackageManager.NameNotFoundException;
     22 import android.content.res.Resources;
     23 import android.content.res.XmlResourceParser;
     24 import android.util.Log;
     25 
     26 import com.android.car.CarLog;
     27 
     28 import java.io.IOException;
     29 import java.util.LinkedList;
     30 
     31 import org.xmlpull.v1.XmlPullParser;
     32 import org.xmlpull.v1.XmlPullParserException;
     33 
     34 /**
     35  * Read meta data containing car application info.
     36  */
     37 public class CarAppMetadataReader {
     38     /** Name of the meta-data attribute for the automotive application XML resource */
     39     private static final String METADATA_ATTRIBUTE = "android.car.application";
     40     /** Name of the tag to declare automotive usage */
     41     private static final String USES_TAG = "uses";
     42     /** Name of the attribute to name the usage type */
     43     private static final String NAME_ATTRIBUTE = "name";
     44 
     45     private static final String NAME_ATTR_TYPE_SERVICE = "service";
     46     private static final String NAME_ATTR_TYPE_ACTIVITY = "activity";
     47 
     48     private static final String CLASS_ATTRIBUTE = "class";
     49 
     50     public static CarAppMetadataInfo parseMetadata(Context context, String packageName) {
     51         int metadataId = 0;
     52         Resources resources = null;
     53         try {
     54             metadataId = getMetadataId(context, packageName);
     55             if (metadataId == 0) {
     56                 return null;
     57             }
     58             PackageManager pm = context.getPackageManager();
     59             resources = pm.getResourcesForApplication(packageName);
     60         } catch (NameNotFoundException e) {
     61             Log.w(CarLog.TAG_PACKAGE, "Cannot read mta data, package:" + packageName, e);
     62             return null;
     63         }
     64 
     65         // Try to open the XML resource
     66         XmlResourceParser parser = null;
     67         try {
     68             parser = resources.getXml(metadataId);
     69         } catch (Resources.NotFoundException e) {
     70             Log.w(CarLog.TAG_PACKAGE, "Resource not found [" + packageName + "]");
     71             return null;
     72         }
     73 
     74         boolean useService = false;
     75         boolean useAllActivities = false;
     76         LinkedList<String> activities = null;
     77         // Now, read the XML and pull out the appropriate "uses" attribute
     78         int eventType;
     79         try {
     80             eventType = parser.next();
     81             while (eventType != XmlPullParser.END_DOCUMENT) {
     82                 if (eventType == XmlPullParser.START_TAG && USES_TAG.equals(parser.getName())) {
     83                     String nameAttribute =
     84                             parser.getAttributeValue(null /*namespace*/, NAME_ATTRIBUTE);
     85                     if (nameAttribute == null) {
     86                         Log.w(CarLog.TAG_PACKAGE, "Bad metadata," + METADATA_ATTRIBUTE +
     87                                 " for pavkage:" + packageName);
     88                         return null;
     89                     }
     90                     switch (nameAttribute) {
     91                         case NAME_ATTR_TYPE_SERVICE:
     92                             useService = true;
     93                             break;
     94                         case NAME_ATTR_TYPE_ACTIVITY: {
     95                             String classAttribute = parser.getAttributeValue(null /*namespace*/,
     96                                     CLASS_ATTRIBUTE);
     97                             if (classAttribute == null) { // all activities
     98                                 useAllActivities = true;
     99                             } else {
    100                                 if (activities == null) {
    101                                     activities = new LinkedList<>();
    102                                 }
    103                                 activities.add(classAttribute);
    104                             }
    105                         } break;
    106                     }
    107                 }
    108                 eventType = parser.next();
    109             }
    110         } catch (XmlPullParserException | IOException e) {
    111             Log.w(CarLog.TAG_PACKAGE, "Resource not parsable [" + packageName + "]");
    112             return null;
    113         }
    114         String[] activityStrings = null;
    115         if (activities != null) {
    116             activityStrings = activities.toArray(new String[activities.size()]);
    117         }
    118         return new CarAppMetadataInfo(useService, useAllActivities, activityStrings);
    119     }
    120 
    121     /**
    122      * Returns the resource ID of the automotive application XML
    123      * @throws NameNotFoundException
    124      */
    125     private static int getMetadataId(Context context, String packageName)
    126             throws NameNotFoundException {
    127         final PackageManager pm = context.getPackageManager();
    128         ApplicationInfo appInfo;
    129         appInfo = pm.getApplicationInfo(packageName, PackageManager.GET_META_DATA /*flags*/);
    130         if (appInfo.metaData == null) {
    131             return 0;
    132         }
    133         return appInfo.metaData.getInt(METADATA_ATTRIBUTE, 0);
    134     }
    135 
    136     /**
    137      * App's metada for car application
    138      */
    139     public static class CarAppMetadataInfo {
    140         /** has "service" use */
    141         public final boolean useService;
    142         /** has "activity" use with no specific class */
    143         public final boolean useAllActivities;
    144         /** has "activity" uses with specific classes */
    145         public String[] activities;
    146 
    147         private CarAppMetadataInfo(boolean useService, boolean useAllActivities,
    148                 String[] activities) {
    149             this.useService = useService;
    150             this.useAllActivities = useAllActivities;
    151             this.activities = activities;
    152         }
    153     }
    154 }
    155