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_LOCALBLOCKREADER_H_
29#define _HDFS_LIBHDFS3_CLIENT_LOCALBLOCKREADER_H_
30
31#include "BlockReader.h"
32#include "Checksum.h"
33#include "FileWrapper.h"
34#include "Memory.h"
35#include "ReadShortCircuitInfo.h"
36#include "SessionConfig.h"
37
38#include <vector>
39
40namespace Hdfs {
41namespace Internal {
42
43class LocalBlockReader: public BlockReader {
44public:
45 LocalBlockReader(const shared_ptr<ReadShortCircuitInfo>& info,
46 const ExtendedBlock & block, int64_t offset, bool verify,
47 SessionConfig & conf, std::vector<char> & buffer);
48
49 ~LocalBlockReader();
50
51 /**
52 * Get how many bytes can be read without blocking.
53 * @return The number of bytes can be read without blocking.
54 */
55 virtual int64_t available() {
56 return length - cursor;
57 }
58
59 /**
60 * To read data from block.
61 * @param buf the buffer used to filled.
62 * @param size the number of bytes to be read.
63 * @return return the number of bytes filled in the buffer,
64 * it may less than size. Return 0 if reach the end of block.
65 */
66 virtual int32_t read(char * buf, int32_t size);
67
68 /**
69 * Move the cursor forward len bytes.
70 * @param len The number of bytes to skip.
71 */
72 virtual void skip(int64_t len);
73
74private:
75 /**
76 * Fill buffer and verify checksum.
77 * @param bufferSize The size of buffer.
78 */
79 void readAndVerify(int32_t bufferSize);
80 int32_t readInternal(char * buf, int32_t len);
81
82private:
83 bool verify; //verify checksum or not.
84 const char * pbuffer;
85 const char * pMetaBuffer;
86 const ExtendedBlock & block;
87 int checksumSize;
88 int chunkSize;
89 int localBufferSize;
90 int position; //point in buffer.
91 int size; //data size in buffer.
92 int64_t cursor; //point in block.
93 int64_t length; //data size of block.
94 shared_ptr<Checksum> checksum;
95 shared_ptr<FileWrapper> dataFd;
96 shared_ptr<FileWrapper> metaFd;
97 shared_ptr<ReadShortCircuitInfo> info;
98 std::vector<char> & buffer;
99 std::vector<char> metaBuffer;
100};
101
102}
103}
104
105#endif /* _HDFS_LIBHDFS3_CLIENT_LOCALBLOCKREADER_H_ */
106