1 | /******************************************************************** |
2 | * Copyright (c) 2013 - 2014, Pivotal Inc. |
3 | * All rights reserved. |
4 | * |
5 | * Author: Zhanwei Wang |
6 | ********************************************************************/ |
7 | /******************************************************************** |
8 | * 2014 - |
9 | * open source under Apache License Version 2.0 |
10 | ********************************************************************/ |
11 | /** |
12 | * Licensed to the Apache Software Foundation (ASF) under one |
13 | * or more contributor license agreements. See the NOTICE file |
14 | * distributed with this work for additional information |
15 | * regarding copyright ownership. The ASF licenses this file |
16 | * to you under the Apache License, Version 2.0 (the |
17 | * "License"); you may not use this file except in compliance |
18 | * with the License. You may obtain a copy of the License at |
19 | * |
20 | * http://www.apache.org/licenses/LICENSE-2.0 |
21 | * |
22 | * Unless required by applicable law or agreed to in writing, software |
23 | * distributed under the License is distributed on an "AS IS" BASIS, |
24 | * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
25 | * See the License for the specific language governing permissions and |
26 | * limitations under the License. |
27 | */ |
28 | #ifndef _HDFS_LIBHDFS3_CLIENT_OUTPUTSTREAM_H_ |
29 | #define _HDFS_LIBHDFS3_CLIENT_OUTPUTSTREAM_H_ |
30 | |
31 | #include "FileSystem.h" |
32 | |
33 | namespace Hdfs { |
34 | |
35 | /** |
36 | * Use the CreateFlag as follows: |
37 | * <ol> |
38 | * <li> CREATE - to create a file if it does not exist, |
39 | * else throw FileAlreadyExists.</li> |
40 | * <li> APPEND - to append to a file if it exists, |
41 | * else throw FileNotFoundException.</li> |
42 | * <li> OVERWRITE - to truncate a file if it exists, |
43 | * else throw FileNotFoundException.</li> |
44 | * <li> CREATE|APPEND - to create a file if it does not exist, |
45 | * else append to an existing file.</li> |
46 | * <li> CREATE|OVERWRITE - to create a file if it does not exist, |
47 | * else overwrite an existing file.</li> |
48 | * <li> SyncBlock - to force closed blocks to the disk device. |
49 | * In addition {@link OutputStream::sync()} should be called after each write, |
50 | * if true synchronous behavior is required.</li> |
51 | * </ol> |
52 | * |
53 | * Following combination is not valid and will result in |
54 | * {@link InvalidParameter}: |
55 | * <ol> |
56 | * <li> APPEND|OVERWRITE</li> |
57 | * <li> CREATE|APPEND|OVERWRITE</li> |
58 | * </ol> |
59 | */ |
60 | enum CreateFlag { |
61 | Create = 0x01, Overwrite = 0x02, Append = 0x04, SyncBlock = 0x08 |
62 | }; |
63 | |
64 | namespace Internal { |
65 | class OutputStreamInter; |
66 | } |
67 | |
68 | /** |
69 | * A output stream used to write data to hdfs. |
70 | */ |
71 | class OutputStream { |
72 | public: |
73 | /** |
74 | * Construct a new OutputStream. |
75 | */ |
76 | OutputStream(); |
77 | /** |
78 | * Destroy a OutputStream instance. |
79 | */ |
80 | ~OutputStream(); |
81 | |
82 | /** |
83 | * To create or append a file. |
84 | * @param fs hdfs file system. |
85 | * @param path the file path. |
86 | * @param flag creation flag, can be Create, Append or Create|Overwrite. |
87 | * @param permission create a new file with given permission. |
88 | * @param createParent if the parent does not exist, create it. |
89 | * @param replication create a file with given number of replication. |
90 | * @param blockSize create a file with given block size. |
91 | */ |
92 | void open(FileSystem & fs, const char * path, int flag = Create, |
93 | const Permission permission = Permission(0644), bool createParent = |
94 | false, int replication = 0, int64_t blockSize = 0); |
95 | |
96 | /** |
97 | * To append data to file. |
98 | * @param buf the data used to append. |
99 | * @param size the data size. |
100 | */ |
101 | void append(const char * buf, int64_t size); |
102 | |
103 | /** |
104 | * Flush all data in buffer and waiting for ack. |
105 | * Will block until get all acks. |
106 | */ |
107 | void flush(); |
108 | |
109 | /** |
110 | * return the current file length. |
111 | * @return current file length. |
112 | */ |
113 | int64_t tell(); |
114 | |
115 | /** |
116 | * the same as flush right now. |
117 | */ |
118 | void sync(); |
119 | |
120 | /** |
121 | * close the stream. |
122 | */ |
123 | void close(); |
124 | |
125 | private: |
126 | Internal::OutputStreamInter * impl; |
127 | |
128 | }; |
129 | |
130 | } |
131 | |
132 | #endif /* _HDFS_LIBHDFS3_CLIENT_OUTPUTSTREAM_H_ */ |
133 | |