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* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you 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
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* See the License for the specific language governing permissions and
* limitations under the License.
#include "BlockReader.h"
#include "Checksum.h"
#include "FileWrapper.h"
#include "SessionConfig.h"
#include "common/SharedPtr.h"
#include "server/BlockLocalPathInfo.h"
#include <stdint.h>
#include <vector>
namespace hdfs {
namespace internal {
class LocalBlockReader: public BlockReader {
LocalBlockReader(const BlockLocalPathInfo & info,
const ExtendedBlock & block, int64_t offset, bool verify,
SessionConfig & conf, std::vector<char> & buffer);
* Get how many bytes can be read without blocking.
* @return The number of bytes can be read without blocking.
virtual int64_t available() {
return length - cursor;
* To read data from block.
* @param buf the buffer used to filled.
* @param size the number of bytes to be read.
* @return return the number of bytes filled in the buffer,
* it may less than size. Return 0 if reach the end of block.
virtual int32_t read(char * buf, int32_t size);
* Move the cursor forward len bytes.
* @param len The number of bytes to skip.
virtual void skip(int64_t len);
* Fill buffer and verify checksum.
* @param bufferSize The size of buffer.
void readAndVerify(int32_t bufferSize);
int32_t readInternal(char * buf, int32_t len);
bool verify; //verify checksum or not.
const char *pbuffer;
const char *pMetaBuffer;
const ExtendedBlock &block;
int checksumSize;
int chunkSize;
int localBufferSize;
int position; //point in buffer.
int size; //data size in buffer.
int64_t cursor; //point in block.
int64_t length; //data size of block.
shared_ptr<Checksum> checksum;
shared_ptr<FileWrapper> dataFd;
shared_ptr<FileWrapper> metaFd;
std::string dataFilePath;
std::string metaFilePath;
std::vector<char> & buffer;
std::vector<char> metaBuffer;