1 /** 2 * Copyright (C) 2019 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.settings.backup; 18 19 import android.app.backup.BackupAgentHelper; 20 import android.app.backup.BackupDataInputStream; 21 import android.app.backup.BackupDataOutput; 22 import android.app.backup.BackupHelper; 23 import android.os.ParcelFileDescriptor; 24 25 import com.android.settings.shortcut.CreateShortcutPreferenceController; 26 27 import java.io.FileInputStream; 28 import java.io.FileOutputStream; 29 import java.io.IOException; 30 31 /** 32 * Backup agent for Settings APK 33 */ 34 public class SettingsBackupHelper extends BackupAgentHelper { 35 36 @Override onCreate()37 public void onCreate() { 38 super.onCreate(); 39 addHelper("no-op", new NoOpHelper()); 40 } 41 42 @Override onRestoreFinished()43 public void onRestoreFinished() { 44 super.onRestoreFinished(); 45 CreateShortcutPreferenceController.updateRestoredShortcuts(this); 46 } 47 48 /** 49 * Backup helper which does not do anything. Having at least one helper ensures that the 50 * transport is not empty and onRestoreFinished is called eventually. 51 */ 52 private static class NoOpHelper implements BackupHelper { 53 54 private final int VERSION_CODE = 1; 55 56 @Override performBackup(ParcelFileDescriptor oldState, BackupDataOutput data, ParcelFileDescriptor newState)57 public void performBackup(ParcelFileDescriptor oldState, BackupDataOutput data, 58 ParcelFileDescriptor newState) { 59 60 try (FileOutputStream out = new FileOutputStream(newState.getFileDescriptor())) { 61 if (getVersionCode(oldState) != VERSION_CODE) { 62 data.writeEntityHeader("dummy", 1); 63 data.writeEntityData(new byte[1], 1); 64 } 65 66 // Write new version code 67 out.write(VERSION_CODE); 68 out.flush(); 69 } catch (IOException e) { } 70 } 71 72 @Override restoreEntity(BackupDataInputStream data)73 public void restoreEntity(BackupDataInputStream data) { } 74 75 @Override writeNewStateDescription(ParcelFileDescriptor newState)76 public void writeNewStateDescription(ParcelFileDescriptor newState) { } 77 getVersionCode(ParcelFileDescriptor state)78 private int getVersionCode(ParcelFileDescriptor state) { 79 if (state == null) { 80 return 0; 81 } 82 try (FileInputStream in = new FileInputStream(state.getFileDescriptor())) { 83 return in.read(); 84 } catch (IOException e) { 85 return 0; 86 } 87 } 88 } 89 } 90