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      1 /**
      2  * Copyright (C) 2014 The Android Open Source Project
      3  *
      4  * Licensed under the Apache License, Version 2.0 (the "License"); you may not
      5  * use this file except in compliance with the License. You may obtain a copy
      6  * 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, WITHOUT
     12  * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
     13  * License for the specific language governing permissions and limitations
     14  * under the License.
     15  */
     16 
     17 package com.android.server.usage;
     18 
     19 import android.util.AtomicFile;
     20 import android.util.Slog;
     21 import android.util.Xml;
     22 import com.android.internal.util.FastXmlSerializer;
     23 import com.android.internal.util.XmlUtils;
     24 import org.xmlpull.v1.XmlPullParser;
     25 import org.xmlpull.v1.XmlPullParserException;
     26 
     27 import java.io.*;
     28 
     29 public class UsageStatsXml {
     30     private static final String TAG = "UsageStatsXml";
     31     private static final int CURRENT_VERSION = 1;
     32     private static final String USAGESTATS_TAG = "usagestats";
     33     private static final String VERSION_ATTR = "version";
     34     static final String CHECKED_IN_SUFFIX = "-c";
     35 
     36     public static long parseBeginTime(AtomicFile file) throws IOException {
     37         return parseBeginTime(file.getBaseFile());
     38     }
     39 
     40     public static long parseBeginTime(File file) throws IOException {
     41         String name = file.getName();
     42 
     43         // Eat as many occurrences of -c as possible. This is due to a bug where -c
     44         // would be appended more than once to a checked-in file, causing a crash
     45         // on boot when indexing files since Long.parseLong() will puke on anything but
     46         // a number.
     47         while (name.endsWith(CHECKED_IN_SUFFIX)) {
     48             name = name.substring(0, name.length() - CHECKED_IN_SUFFIX.length());
     49         }
     50 
     51         try {
     52             return Long.parseLong(name);
     53         } catch (NumberFormatException e) {
     54             throw new IOException(e);
     55         }
     56     }
     57 
     58     public static void read(AtomicFile file, IntervalStats statsOut) throws IOException {
     59         try {
     60             FileInputStream in = file.openRead();
     61             try {
     62                 statsOut.beginTime = parseBeginTime(file);
     63                 read(in, statsOut);
     64                 statsOut.lastTimeSaved = file.getLastModifiedTime();
     65             } finally {
     66                 try {
     67                     in.close();
     68                 } catch (IOException e) {
     69                     // Empty
     70                 }
     71             }
     72         } catch (FileNotFoundException e) {
     73             Slog.e(TAG, "UsageStats Xml", e);
     74             throw e;
     75         }
     76     }
     77 
     78     public static void write(AtomicFile file, IntervalStats stats) throws IOException {
     79         FileOutputStream fos = file.startWrite();
     80         try {
     81             write(fos, stats);
     82             file.finishWrite(fos);
     83             fos = null;
     84         } finally {
     85             // When fos is null (successful write), this will no-op
     86             file.failWrite(fos);
     87         }
     88     }
     89 
     90     static void read(InputStream in, IntervalStats statsOut) throws IOException {
     91         XmlPullParser parser = Xml.newPullParser();
     92         try {
     93             parser.setInput(in, "utf-8");
     94             XmlUtils.beginDocument(parser, USAGESTATS_TAG);
     95             String versionStr = parser.getAttributeValue(null, VERSION_ATTR);
     96             try {
     97                 switch (Integer.parseInt(versionStr)) {
     98                     case 1:
     99                         UsageStatsXmlV1.read(parser, statsOut);
    100                         break;
    101 
    102                     default:
    103                         Slog.e(TAG, "Unrecognized version " + versionStr);
    104                         throw new IOException("Unrecognized version " + versionStr);
    105                 }
    106             } catch (NumberFormatException e) {
    107                 Slog.e(TAG, "Bad version");
    108                 throw new IOException(e);
    109             }
    110         } catch (XmlPullParserException e) {
    111             Slog.e(TAG, "Failed to parse Xml", e);
    112             throw new IOException(e);
    113         }
    114     }
    115 
    116     static void write(OutputStream out, IntervalStats stats) throws IOException {
    117         FastXmlSerializer xml = new FastXmlSerializer();
    118         xml.setOutput(out, "utf-8");
    119         xml.startDocument("utf-8", true);
    120         xml.setFeature("http://xmlpull.org/v1/doc/features.html#indent-output", true);
    121         xml.startTag(null, USAGESTATS_TAG);
    122         xml.attribute(null, VERSION_ATTR, Integer.toString(CURRENT_VERSION));
    123 
    124         UsageStatsXmlV1.write(xml, stats);
    125 
    126         xml.endTag(null, USAGESTATS_TAG);
    127         xml.endDocument();
    128     }
    129 }