| /* |
| * 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 java.io.InputStream; |
| import java.io.IOException; |
| |
| /** |
| * Provides an {@link java.io.InputStream}-like interface for accessing an |
| * entity's data during a restore operation. Used by {@link BackupHelper} classes within the {@link |
| * BackupAgentHelper} mechanism. |
| * <p> |
| * When {@link BackupHelper#restoreEntity(BackupDataInputStream) BackupHelper.restoreEntity()} |
| * is called, the current entity's header has already been read from the underlying |
| * {@link BackupDataInput}. The entity's key string and total data size are available |
| * through this class's {@link #getKey()} and {@link #size()} methods, respectively. |
| * <p class="note"> |
| * <strong>Note:</strong> The caller should take care not to seek or close the underlying data |
| * source, nor read more than {@link #size()} bytes from the stream.</p> |
| * |
| * @see BackupAgentHelper |
| * @see BackupHelper |
| */ |
| public class BackupDataInputStream extends InputStream { |
| |
| String key; |
| int dataSize; |
| |
| BackupDataInput mData; |
| byte[] mOneByte; |
| |
| /** @hide */ |
| BackupDataInputStream(BackupDataInput data) { |
| mData = data; |
| } |
| |
| /** |
| * Read one byte of entity data from the stream, returning it as |
| * an integer value. If more than {@link #size()} bytes of data |
| * are read from the stream, the output of this method is undefined. |
| * |
| * @return The byte read, or undefined if the end of the stream has been reached. |
| */ |
| public int read() throws IOException { |
| byte[] one = mOneByte; |
| if (mOneByte == null) { |
| one = mOneByte = new byte[1]; |
| } |
| mData.readEntityData(one, 0, 1); |
| return one[0]; |
| } |
| |
| /** |
| * Read up to {@code size} bytes of data into a byte array, beginning at position |
| * {@code offset} within the array. |
| * |
| * @param b Byte array into which the data will be read |
| * @param offset The data will be stored in {@code b} beginning at this index |
| * within the array. |
| * @param size The number of bytes to read in this operation. If insufficient |
| * data exists within the entity to fulfill this request, only as much data |
| * will be read as is available. |
| * @return The number of bytes of data read, or zero if all of the entity's |
| * data has already been read. |
| */ |
| public int read(byte[] b, int offset, int size) throws IOException { |
| return mData.readEntityData(b, offset, size); |
| } |
| |
| /** |
| * Read enough entity data into a byte array to fill the array. |
| * |
| * @param b Byte array to fill with data from the stream. If the stream does not |
| * have sufficient data to fill the array, then the contents of the remainder of |
| * the array will be undefined. |
| * @return The number of bytes of data read, or zero if all of the entity's |
| * data has already been read. |
| */ |
| public int read(byte[] b) throws IOException { |
| return mData.readEntityData(b, 0, b.length); |
| } |
| |
| /** |
| * Report the key string associated with this entity within the backup data set. |
| * |
| * @return The key string for this entity, equivalent to calling |
| * {@link BackupDataInput#getKey()} on the underlying {@link BackupDataInput}. |
| */ |
| public String getKey() { |
| return this.key; |
| } |
| |
| /** |
| * Report the total number of bytes of data available for the current entity. |
| * |
| * @return The number of data bytes available, equivalent to calling |
| * {@link BackupDataInput#getDataSize()} on the underlying {@link BackupDataInput}. |
| */ |
| public int size() { |
| return this.dataSize; |
| } |
| } |
| |
| |