BackupDataOutput.java revision fc922f115325371aaadd4e423472476303039a72 
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
17package android.app.backup;
18
19import java.io.FileDescriptor;
20import java.io.IOException;
21
22/**
23 * STOPSHIP: document
24 */
25public class BackupDataOutput {
26    int mBackupWriter;
27
28    /** @hide */
29    public BackupDataOutput(FileDescriptor fd) {
30        if (fd == null) throw new NullPointerException();
31        mBackupWriter = ctor(fd);
32        if (mBackupWriter == 0) {
33            throw new RuntimeException("Native initialization failed with fd=" + fd);
34        }
35    }
36
37    /**
38     * Mark the beginning of one record in the backup data stream.
39     *
40     * @param key
41     * @param dataSize The size in bytes of this record's data.  Passing a dataSize
42     *    of -1 indicates that the record under this key should be deleted.
43     * @return The number of bytes written to the backup stream
44     * @throws IOException if the write failed
45     */
46    public int writeEntityHeader(String key, int dataSize) throws IOException {
47        int result = writeEntityHeader_native(mBackupWriter, key, dataSize);
48        if (result >= 0) {
49            return result;
50        } else {
51            throw new IOException("result=0x" + Integer.toHexString(result));
52        }
53    }
54
55    /**
56     * Write a chunk of data under the current entity to the backup transport.
57     * @param data A raw data buffer to send
58     * @param size The number of bytes to be sent in this chunk
59     * @return the number of bytes written
60     * @throws IOException if the write failed
61     */
62    public int writeEntityData(byte[] data, int size) throws IOException {
63        int result = writeEntityData_native(mBackupWriter, data, size);
64        if (result >= 0) {
65            return result;
66        } else {
67            throw new IOException("result=0x" + Integer.toHexString(result));
68        }
69    }
70
71    /** @hide */
72    public void setKeyPrefix(String keyPrefix) {
73        setKeyPrefix_native(mBackupWriter, keyPrefix);
74    }
75
76    /** @hide */
77    protected void finalize() throws Throwable {
78        try {
79            dtor(mBackupWriter);
80        } finally {
81            super.finalize();
82        }
83    }
84
85    private native static int ctor(FileDescriptor fd);
86    private native static void dtor(int mBackupWriter);
87
88    private native static int writeEntityHeader_native(int mBackupWriter, String key, int dataSize);
89    private native static int writeEntityData_native(int mBackupWriter, byte[] data, int size);
90    private native static void setKeyPrefix_native(int mBackupWriter, String keyPrefix);
91}
92
93