| /* |
| * Copyright (C) 2009 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 android.app.backup; |
| |
| import android.content.Context; |
| import android.os.ParcelFileDescriptor; |
| import android.util.Log; |
| |
| import java.io.File; |
| |
| /** |
| * A helper class that can be used in conjunction with |
| * {@link android.app.backup.BackupAgentHelper} to manage the backup of a set of |
| * files. Whenever backup is performed, all files changed since the last backup |
| * will be saved in their entirety. When backup first occurs, |
| * every file in the list provided to {@link #FileBackupHelper} will be backed up. |
| * <p> |
| * During restore, if the helper encounters data for a file that was not |
| * specified when the FileBackupHelper object was constructed, that data |
| * will be ignored. |
| * <p class="note"><strong>Note:</strong> This should be |
| * used only with small configuration files, not large binary files. |
| */ |
| public class FileBackupHelper extends FileBackupHelperBase implements BackupHelper { |
| private static final String TAG = "FileBackupHelper"; |
| private static final boolean DEBUG = false; |
| |
| Context mContext; |
| File mFilesDir; |
| String[] mFiles; |
| |
| /** |
| * Construct a helper to manage backup/restore of entire files within the |
| * application's data directory hierarchy. |
| * |
| * @param context The backup agent's Context object |
| * @param files A list of the files to be backed up or restored. |
| */ |
| public FileBackupHelper(Context context, String... files) { |
| super(context); |
| |
| mContext = context; |
| mFilesDir = context.getFilesDir(); |
| mFiles = files; |
| } |
| |
| /** |
| * Based on <code>oldState</code>, determine which of the files from the |
| * application's data directory need to be backed up, write them to the data |
| * stream, and fill in <code>newState</code> with the state as it exists |
| * now. When <code>oldState</code> is <code>null</code>, all the files will |
| * be backed up. |
| * <p> |
| * This should only be called directly from within the {@link BackupAgentHelper} |
| * implementation. See |
| * {@link android.app.backup.BackupAgent#onBackup(ParcelFileDescriptor, BackupDataOutput, ParcelFileDescriptor)} |
| * for a description of parameter meanings. |
| */ |
| public void performBackup(ParcelFileDescriptor oldState, BackupDataOutput data, |
| ParcelFileDescriptor newState) { |
| // file names |
| String[] files = mFiles; |
| File base = mContext.getFilesDir(); |
| final int N = files.length; |
| String[] fullPaths = new String[N]; |
| for (int i=0; i<N; i++) { |
| fullPaths[i] = (new File(base, files[i])).getAbsolutePath(); |
| } |
| |
| // go |
| performBackup_checked(oldState, data, newState, fullPaths, files); |
| } |
| |
| /** |
| * Restore one record [representing a single file] from the restore dataset. |
| * <p> |
| * This should only be called directly from within the {@link BackupAgentHelper} |
| * implementation. |
| */ |
| public void restoreEntity(BackupDataInputStream data) { |
| if (DEBUG) Log.d(TAG, "got entity '" + data.getKey() + "' size=" + data.size()); |
| String key = data.getKey(); |
| if (isKeyInList(key, mFiles)) { |
| File f = new File(mFilesDir, key); |
| writeFile(f, data); |
| } |
| } |
| } |
| |