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_REMOTEBLOCKREADER_H_
29#define _HDFS_LIBHDFS3_CLIENT_REMOTEBLOCKREADER_H_
30
31#include "BlockReader.h"
32#include "Checksum.h"
33#include "DataTransferProtocol.h"
34#include "Memory.h"
35#include "network/BufferedSocketReader.h"
36#include "network/TcpSocket.h"
37#include "PacketHeader.h"
38#include "PeerCache.h"
39#include "server/DatanodeInfo.h"
40#include "server/LocatedBlocks.h"
41#include "SessionConfig.h"
42
43namespace Hdfs {
44namespace Internal {
45
46class RemoteBlockReader: public BlockReader {
47public:
48 RemoteBlockReader(const ExtendedBlock& eb, DatanodeInfo& datanode,
49 PeerCache& peerCache, int64_t start, int64_t len,
50 const Token& token, const char* clientName, bool verify,
51 SessionConfig& conf);
52
53 ~RemoteBlockReader();
54
55 /**
56 * Get how many bytes can be read without blocking.
57 * @return The number of bytes can be read without blocking.
58 */
59 virtual int64_t available();
60
61 /**
62 * To read data from block.
63 * @param buf the buffer used to filled.
64 * @param size the number of bytes to be read.
65 * @return return the number of bytes filled in the buffer,
66 * it may less than size. Return 0 if reach the end of block.
67 */
68 virtual int32_t read(char * buf, int32_t len);
69
70 /**
71 * Move the cursor forward len bytes.
72 * @param len The number of bytes to skip.
73 */
74 virtual void skip(int64_t len);
75
76private:
77 bool readTrailingEmptyPacket();
78 shared_ptr<PacketHeader> readPacketHeader();
79 shared_ptr<Socket> getNextPeer(const DatanodeInfo& dn);
80 void checkResponse();
81 void readNextPacket();
82 void sendStatus();
83 void verifyChecksum(int chunks);
84
85private:
86 bool sentStatus;
87 bool verify; //verify checksum or not.
88 const ExtendedBlock & binfo;
89 DatanodeInfo & datanode;
90 int checksumSize;
91 int chunkSize;
92 int connTimeout;
93 int position; //point in buffer.
94 int readTimeout;
95 int size; //data size in buffer.
96 int writeTimeout;
97 int64_t cursor; //point in block.
98 int64_t endOffset; //offset in block requested to read to.
99 int64_t lastSeqNo; //segno of the last chunk received
100 PeerCache& peerCache;
101 shared_ptr<BufferedSocketReader> in;
102 shared_ptr<Checksum> checksum;
103 shared_ptr<DataTransferProtocol> sender;
104 shared_ptr<PacketHeader> lastHeader;
105 shared_ptr<Socket> sock;
106 std::vector<char> buffer;
107};
108
109}
110}
111#endif /* _HDFS_LIBHDFS3_CLIENT_REMOTEBLOCKREADER_H_ */
112