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
17package com.android.server.usage;
18
19import android.util.AtomicFile;
20import android.util.Slog;
21import android.util.Xml;
22import com.android.internal.util.FastXmlSerializer;
23import com.android.internal.util.XmlUtils;
24import org.xmlpull.v1.XmlPullParser;
25import org.xmlpull.v1.XmlPullParserException;
26
27import java.io.*;
28
29public 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) {
37        return parseBeginTime(file.getBaseFile());
38    }
39
40    public static long parseBeginTime(File file) {
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        return Long.parseLong(name);
51    }
52
53    public static void read(AtomicFile file, IntervalStats statsOut) throws IOException {
54        try {
55            FileInputStream in = file.openRead();
56            try {
57                statsOut.beginTime = parseBeginTime(file);
58                read(in, statsOut);
59                statsOut.lastTimeSaved = file.getLastModifiedTime();
60            } finally {
61                try {
62                    in.close();
63                } catch (IOException e) {
64                    // Empty
65                }
66            }
67        } catch (FileNotFoundException e) {
68            Slog.e(TAG, "UsageStats Xml", e);
69            throw e;
70        }
71    }
72
73    public static void write(AtomicFile file, IntervalStats stats) throws IOException {
74        FileOutputStream fos = file.startWrite();
75        try {
76            write(fos, stats);
77            file.finishWrite(fos);
78            fos = null;
79        } finally {
80            // When fos is null (successful write), this will no-op
81            file.failWrite(fos);
82        }
83    }
84
85    private static void read(InputStream in, IntervalStats statsOut) throws IOException {
86        XmlPullParser parser = Xml.newPullParser();
87        try {
88            parser.setInput(in, "utf-8");
89            XmlUtils.beginDocument(parser, USAGESTATS_TAG);
90            String versionStr = parser.getAttributeValue(null, VERSION_ATTR);
91            try {
92                switch (Integer.parseInt(versionStr)) {
93                    case 1:
94                        UsageStatsXmlV1.read(parser, statsOut);
95                        break;
96
97                    default:
98                        Slog.e(TAG, "Unrecognized version " + versionStr);
99                        throw new IOException("Unrecognized version " + versionStr);
100                }
101            } catch (NumberFormatException e) {
102                Slog.e(TAG, "Bad version");
103                throw new IOException(e);
104            }
105        } catch (XmlPullParserException e) {
106            Slog.e(TAG, "Failed to parse Xml", e);
107            throw new IOException(e);
108        }
109    }
110
111    private static void write(OutputStream out, IntervalStats stats) throws IOException {
112        FastXmlSerializer xml = new FastXmlSerializer();
113        xml.setOutput(out, "utf-8");
114        xml.startDocument("utf-8", true);
115        xml.setFeature("http://xmlpull.org/v1/doc/features.html#indent-output", true);
116        xml.startTag(null, USAGESTATS_TAG);
117        xml.attribute(null, VERSION_ATTR, Integer.toString(CURRENT_VERSION));
118
119        UsageStatsXmlV1.write(xml, stats);
120
121        xml.endTag(null, USAGESTATS_TAG);
122        xml.endDocument();
123    }
124}
125