1 /* 2 * Copyright (C) 2022 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.companion; 18 19 import static org.xmlpull.v1.XmlPullParser.END_TAG; 20 import static org.xmlpull.v1.XmlPullParser.START_TAG; 21 22 import android.annotation.NonNull; 23 import android.annotation.UserIdInt; 24 import android.os.Environment; 25 import android.util.AtomicFile; 26 import android.util.Slog; 27 28 import com.android.internal.util.FunctionalUtils.ThrowingConsumer; 29 30 import org.xmlpull.v1.XmlPullParser; 31 import org.xmlpull.v1.XmlPullParserException; 32 33 import java.io.File; 34 import java.io.FileOutputStream; 35 36 final class DataStoreUtils { 37 private static final String TAG = "CompanionDevice_DataStoreUtils"; 38 isStartOfTag(@onNull XmlPullParser parser, @NonNull String tag)39 static boolean isStartOfTag(@NonNull XmlPullParser parser, @NonNull String tag) 40 throws XmlPullParserException { 41 return parser.getEventType() == START_TAG && tag.equals(parser.getName()); 42 } 43 isEndOfTag(@onNull XmlPullParser parser, @NonNull String tag)44 static boolean isEndOfTag(@NonNull XmlPullParser parser, @NonNull String tag) 45 throws XmlPullParserException { 46 return parser.getEventType() == END_TAG && tag.equals(parser.getName()); 47 } 48 49 /** 50 * Creates {@link AtomicFile} object that represents the back-up for the given user. 51 * 52 * IMPORTANT: the method will ALWAYS return the same {@link AtomicFile} object, which makes it 53 * possible to synchronize reads and writes to the file using the returned object. 54 * 55 * @param userId the userId to retrieve the storage file 56 * @param fileName the storage file name 57 * @return an AtomicFile for the user 58 */ 59 @NonNull createStorageFileForUser(@serIdInt int userId, String fileName)60 static AtomicFile createStorageFileForUser(@UserIdInt int userId, String fileName) { 61 return new AtomicFile(getBaseStorageFileForUser(userId, fileName)); 62 } 63 64 @NonNull getBaseStorageFileForUser(@serIdInt int userId, String fileName)65 private static File getBaseStorageFileForUser(@UserIdInt int userId, String fileName) { 66 return new File(Environment.getDataSystemDeDirectory(userId), fileName); 67 } 68 69 /** 70 * Writing to file could fail, for example, if the user has been recently removed and so was 71 * their DE (/data/system_de/<user-id>/) directory. 72 */ writeToFileSafely( @onNull AtomicFile file, @NonNull ThrowingConsumer<FileOutputStream> consumer)73 static void writeToFileSafely( 74 @NonNull AtomicFile file, @NonNull ThrowingConsumer<FileOutputStream> consumer) { 75 try { 76 file.write(consumer); 77 } catch (Exception e) { 78 Slog.e(TAG, "Error while writing to file " + file, e); 79 } 80 } 81 DataStoreUtils()82 private DataStoreUtils() { 83 } 84 } 85