| /* |
| * Copyright (C) 2017 The Android Open Source Project |
| * |
| * Licensed under the Apache License, Version 2.0 (the "License"); |
| * you may not use this file except in compliance with the License. |
| * You may obtain a copy of the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, software |
| * distributed under the License is distributed on an "AS IS" BASIS, |
| * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| * See the License for the specific language governing permissions and |
| * limitations under the License |
| */ |
| |
| package com.android.server.backup; |
| |
| import android.annotation.Nullable; |
| import android.util.Slog; |
| |
| import java.io.BufferedInputStream; |
| import java.io.DataInputStream; |
| import java.io.File; |
| import java.io.FileInputStream; |
| import java.io.IOException; |
| import java.io.RandomAccessFile; |
| import java.util.ArrayList; |
| import java.util.List; |
| import java.util.function.Consumer; |
| |
| /** |
| * A journal of packages that have indicated that their data has changed (and therefore should be |
| * backed up in the next scheduled K/V backup pass). |
| * |
| * <p>This information is persisted to the filesystem so that it is not lost in the event of a |
| * reboot. |
| */ |
| public class DataChangedJournal { |
| private static final String TAG = "DataChangedJournal"; |
| private static final String FILE_NAME_PREFIX = "journal"; |
| |
| /** |
| * Journals tend to be on the order of a few kilobytes, hence setting the buffer size to 8kb. |
| */ |
| private static final int BUFFER_SIZE_BYTES = 8 * 1024; |
| |
| private final File mFile; |
| |
| /** |
| * Constructs an instance that reads from and writes to the given file. |
| */ |
| DataChangedJournal(File file) { |
| mFile = file; |
| } |
| |
| /** |
| * Adds the given package to the journal. |
| * |
| * @param packageName The name of the package whose data has changed. |
| * @throws IOException if there is an IO error writing to the journal file. |
| */ |
| public void addPackage(String packageName) throws IOException { |
| try (RandomAccessFile out = new RandomAccessFile(mFile, "rws")) { |
| out.seek(out.length()); |
| out.writeUTF(packageName); |
| } |
| } |
| |
| /** |
| * Invokes {@link Consumer#accept(Object)} with every package name in the journal file. |
| * |
| * @param consumer The callback. |
| * @throws IOException If there is an IO error reading from the file. |
| */ |
| public void forEach(Consumer<String> consumer) throws IOException { |
| try ( |
| BufferedInputStream bufferedInputStream = new BufferedInputStream( |
| new FileInputStream(mFile), BUFFER_SIZE_BYTES); |
| DataInputStream dataInputStream = new DataInputStream(bufferedInputStream) |
| ) { |
| while (dataInputStream.available() > 0) { |
| String packageName = dataInputStream.readUTF(); |
| consumer.accept(packageName); |
| } |
| } |
| } |
| |
| /** |
| * Returns a list with the packages in this journal. |
| * |
| * @throws IOException If there is an IO error reading from the file. |
| */ |
| public List<String> getPackages() throws IOException { |
| List<String> packages = new ArrayList<>(); |
| forEach(packages::add); |
| return packages; |
| } |
| |
| /** |
| * Deletes the journal from the filesystem. |
| * |
| * @return {@code true} if successfully deleted journal. |
| */ |
| public boolean delete() { |
| return mFile.delete(); |
| } |
| |
| @Override |
| public boolean equals(@Nullable Object object) { |
| if (object instanceof DataChangedJournal) { |
| DataChangedJournal that = (DataChangedJournal) object; |
| try { |
| return this.mFile.getCanonicalPath().equals(that.mFile.getCanonicalPath()); |
| } catch (IOException exception) { |
| return false; |
| } |
| } |
| return false; |
| } |
| |
| @Override |
| public String toString() { |
| return mFile.toString(); |
| } |
| |
| /** |
| * Creates a new journal with a random file name in the given journal directory. |
| * |
| * @param journalDirectory The directory where journals are kept. |
| * @return The journal. |
| * @throws IOException if there is an IO error creating the file. |
| */ |
| static DataChangedJournal newJournal(File journalDirectory) throws IOException { |
| return new DataChangedJournal( |
| File.createTempFile(FILE_NAME_PREFIX, null, journalDirectory)); |
| } |
| |
| /** |
| * Returns a list of journals in the given journal directory. |
| */ |
| static ArrayList<DataChangedJournal> listJournals(File journalDirectory) { |
| ArrayList<DataChangedJournal> journals = new ArrayList<>(); |
| File[] journalFiles = journalDirectory.listFiles(); |
| if (journalFiles == null) { |
| Slog.w(TAG, "Failed to read journal files"); |
| return journals; |
| } |
| for (File file : journalFiles) { |
| journals.add(new DataChangedJournal(file)); |
| } |
| return journals; |
| } |
| } |