1 /* 2 * Copyright (C) 2009 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 android.app.backup; 18 19 import android.compat.annotation.UnsupportedAppUsage; 20 import android.os.ParcelFileDescriptor; 21 import android.util.Log; 22 23 import java.io.FileDescriptor; 24 import java.io.IOException; 25 import java.util.Map; 26 import java.util.TreeMap; 27 28 /** @hide */ 29 public class BackupHelperDispatcher { 30 private static final String TAG = "BackupHelperDispatcher"; 31 32 private static class Header { 33 @UnsupportedAppUsage 34 int chunkSize; // not including the header 35 @UnsupportedAppUsage 36 String keyPrefix; 37 } 38 39 TreeMap<String,BackupHelper> mHelpers = new TreeMap<String,BackupHelper>(); 40 BackupHelperDispatcher()41 public BackupHelperDispatcher() { 42 } 43 addHelper(String keyPrefix, BackupHelper helper)44 public void addHelper(String keyPrefix, BackupHelper helper) { 45 mHelpers.put(keyPrefix, helper); 46 } 47 performBackup(ParcelFileDescriptor oldState, BackupDataOutput data, ParcelFileDescriptor newState)48 public void performBackup(ParcelFileDescriptor oldState, BackupDataOutput data, 49 ParcelFileDescriptor newState) throws IOException { 50 // First, do the helpers that we've already done, since they're already in the state 51 // file. 52 int err; 53 Header header = new Header(); 54 TreeMap<String,BackupHelper> helpers = (TreeMap<String,BackupHelper>)mHelpers.clone(); 55 FileDescriptor oldStateFD = null; 56 57 if (oldState != null) { 58 oldStateFD = oldState.getFileDescriptor(); 59 while ((err = readHeader_native(header, oldStateFD)) >= 0) { 60 if (err == 0) { 61 BackupHelper helper = helpers.get(header.keyPrefix); 62 Log.d(TAG, "handling existing helper '" + header.keyPrefix + "' " + helper); 63 if (helper != null) { 64 doOneBackup(oldState, data, newState, header, helper); 65 helpers.remove(header.keyPrefix); 66 } else { 67 skipChunk_native(oldStateFD, header.chunkSize); 68 } 69 } 70 } 71 } 72 73 // Then go through and do the rest that we haven't done. 74 for (Map.Entry<String,BackupHelper> entry: helpers.entrySet()) { 75 header.keyPrefix = entry.getKey(); 76 Log.d(TAG, "handling new helper '" + header.keyPrefix + "'"); 77 BackupHelper helper = entry.getValue(); 78 doOneBackup(oldState, data, newState, header, helper); 79 } 80 } 81 doOneBackup(ParcelFileDescriptor oldState, BackupDataOutput data, ParcelFileDescriptor newState, Header header, BackupHelper helper)82 private void doOneBackup(ParcelFileDescriptor oldState, BackupDataOutput data, 83 ParcelFileDescriptor newState, Header header, BackupHelper helper) 84 throws IOException { 85 int err; 86 FileDescriptor newStateFD = newState.getFileDescriptor(); 87 88 // allocate space for the header in the file 89 int pos = allocateHeader_native(header, newStateFD); 90 if (pos < 0) { 91 throw new IOException("allocateHeader_native failed (error " + pos + ")"); 92 } 93 94 data.setKeyPrefix(header.keyPrefix); 95 96 // do the backup 97 helper.performBackup(oldState, data, newState); 98 99 // fill in the header (seeking back to pos). The file pointer will be returned to 100 // where it was at the end of performBackup. Header.chunkSize will not be filled in. 101 err = writeHeader_native(header, newStateFD, pos); 102 if (err != 0) { 103 throw new IOException("writeHeader_native failed (error " + err + ")"); 104 } 105 } 106 performRestore(BackupDataInput input, int appVersionCode, ParcelFileDescriptor newState)107 public void performRestore(BackupDataInput input, int appVersionCode, 108 ParcelFileDescriptor newState) 109 throws IOException { 110 boolean alreadyComplained = false; 111 112 BackupDataInputStream stream = new BackupDataInputStream(input); 113 while (input.readNextHeader()) { 114 115 String rawKey = input.getKey(); 116 int pos = rawKey.indexOf(':'); 117 if (pos > 0) { 118 String prefix = rawKey.substring(0, pos); 119 BackupHelper helper = mHelpers.get(prefix); 120 if (helper != null) { 121 stream.dataSize = input.getDataSize(); 122 stream.key = rawKey.substring(pos+1); 123 helper.restoreEntity(stream); 124 } else { 125 if (!alreadyComplained) { 126 Log.w(TAG, "Couldn't find helper for: '" + rawKey + "'"); 127 alreadyComplained = true; 128 } 129 } 130 } else { 131 if (!alreadyComplained) { 132 Log.w(TAG, "Entity with no prefix: '" + rawKey + "'"); 133 alreadyComplained = true; 134 } 135 } 136 input.skipEntityData(); // In case they didn't consume the data. 137 } 138 139 // Write out the state files -- mHelpers is a TreeMap, so the order is well defined. 140 for (BackupHelper helper: mHelpers.values()) { 141 helper.writeNewStateDescription(newState); 142 } 143 } 144 readHeader_native(Header h, FileDescriptor fd)145 private static native int readHeader_native(Header h, FileDescriptor fd); skipChunk_native(FileDescriptor fd, int bytesToSkip)146 private static native int skipChunk_native(FileDescriptor fd, int bytesToSkip); 147 allocateHeader_native(Header h, FileDescriptor fd)148 private static native int allocateHeader_native(Header h, FileDescriptor fd); writeHeader_native(Header h, FileDescriptor fd, int pos)149 private static native int writeHeader_native(Header h, FileDescriptor fd, int pos); 150 } 151 152