254 lines
7.5 KiB
C++
254 lines
7.5 KiB
C++
/**
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* Licensed to the Apache Software Foundation (ASF) under one
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* or more contributor license agreements. See the NOTICE file
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* distributed with this work for additional information
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* regarding copyright ownership. The ASF licenses this file
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* to you under the Apache License, Version 2.0 (the
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* "License"); you may not use this file except in compliance
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* with the License. You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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// Copyright (c) 2012 Facebook. All rights reserved.
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#ifndef LEVELDB_HDFS_FILE_H
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#define LEVELDB_HDFS_FILE_H
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#include <algorithm>
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#include <stdio.h>
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#include <sys/time.h>
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#include <time.h>
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#include <iostream>
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#include "leveldb/env.h"
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#include "leveldb/status.h"
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#ifdef USE_HDFS
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#include "hdfs/hdfs.h"
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namespace leveldb {
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static const std::string kProto = "hdfs://";
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static const std::string pathsep = "/";
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// Thrown during execution when there is an issue with the supplied
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// arguments.
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class HdfsUsageException : public std::exception { };
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// A simple exception that indicates something went wrong that is not
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// recoverable. The intention is for the message to be printed (with
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// nothing else) and the process terminate.
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class HdfsFatalException : public std::exception {
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public:
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explicit HdfsFatalException(const std::string& s) : what_(s) { }
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virtual ~HdfsFatalException() throw() { }
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virtual const char* what() const throw() {
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return what_.c_str();
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}
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private:
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const std::string what_;
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};
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//
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// The HDFS environment for leveldb. This class overrides all the
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// file/dir access methods and delegates the thread-mgmt methods to the
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// default posix environment.
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//
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class HdfsEnv : public Env {
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public:
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HdfsEnv(const std::string& fsname) : fsname_(fsname) {
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posixEnv = Env::Default();
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fileSys_ = connectToPath(fsname_);
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}
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virtual ~HdfsEnv() {
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fprintf(stderr, "Destroying HdfsEnv::Default()\n");
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hdfsDisconnect(fileSys_);
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}
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virtual Status NewSequentialFile(const std::string& fname,
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SequentialFile** result);
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virtual Status NewRandomAccessFile(const std::string& fname,
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RandomAccessFile** result);
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virtual Status NewWritableFile(const std::string& fname,
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WritableFile** result);
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virtual bool FileExists(const std::string& fname);
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virtual Status GetChildren(const std::string& path,
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std::vector<std::string>* result);
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virtual Status DeleteFile(const std::string& fname);
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virtual Status CreateDir(const std::string& name);
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virtual Status DeleteDir(const std::string& name);
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virtual Status GetFileSize(const std::string& fname, uint64_t* size);
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virtual Status RenameFile(const std::string& src, const std::string& target);
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virtual Status LockFile(const std::string& fname, FileLock** lock);
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virtual Status UnlockFile(FileLock* lock);
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virtual Status NewLogger(const std::string& fname, Logger** result);
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virtual void Schedule( void (*function)(void* arg), void* arg) {
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posixEnv->Schedule(function, arg);
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}
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virtual void StartThread(void (*function)(void* arg), void* arg) {
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posixEnv->StartThread(function, arg);
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}
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virtual Status GetTestDirectory(std::string* path) {
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return posixEnv->GetTestDirectory(path);
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}
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virtual uint64_t NowMicros() {
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return posixEnv->NowMicros();
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}
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virtual void SleepForMicroseconds(int micros) {
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posixEnv->SleepForMicroseconds(micros);
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}
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static uint64_t gettid() {
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assert(sizeof(pthread_t) <= sizeof(uint64_t));
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return (uint64_t)pthread_self();
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}
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private:
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std::string fsname_; // string of the form "hdfs://hostname:port/"
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hdfsFS fileSys_; // a single FileSystem object for all files
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Env* posixEnv; // This object is derived from Env, but not from
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// posixEnv. We have posixnv as an encapsulated
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// object here so that we can use posix timers,
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// posix threads, etc.
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/**
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* If the URI is specified of the form hdfs://server:port/path,
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* then connect to the specified cluster
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* else connect to default.
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*/
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hdfsFS connectToPath(const std::string& uri) {
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if (uri.empty()) {
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return NULL;
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}
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if (uri.find(kProto) != 0) {
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// uri doesn't start with hdfs:// -> use default:0, which is special
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// to libhdfs.
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return hdfsConnectNewInstance("default", 0);
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}
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const std::string hostport = uri.substr(kProto.length());
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std::vector <std::string> parts;
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split(hostport, ':', parts);
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if (parts.size() != 2) {
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throw HdfsFatalException("Bad uri for hdfs " + uri);
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}
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// parts[0] = hosts, parts[1] = port/xxx/yyy
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std::string host(parts[0]);
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std::string remaining(parts[1]);
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int rem = remaining.find(pathsep);
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std::string portStr = (rem == 0 ? remaining :
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remaining.substr(0, rem));
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tPort port;
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port = atoi(portStr.c_str());
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if (port == 0) {
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throw HdfsFatalException("Bad host-port for hdfs " + uri);
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}
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hdfsFS fs = hdfsConnectNewInstance(host.c_str(), port);
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return fs;
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}
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void split(const std::string &s, char delim,
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std::vector<std::string> &elems) {
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elems.clear();
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size_t prev = 0;
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size_t pos = s.find(delim);
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while (pos != std::string::npos) {
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elems.push_back(s.substr(prev, pos));
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prev = pos + 1;
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pos = s.find(delim, prev);
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}
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elems.push_back(s.substr(prev, s.size()));
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}
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};
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} // namespace leveldb
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#else // USE_HDFS
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namespace leveldb {
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class HdfsEnv : public Env {
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public:
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HdfsEnv(const std::string& fsname) {
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fprintf(stderr, "You have not build leveldb with HDFS support\n");
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fprintf(stderr, "Please see hdfs/README for details\n");
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throw new std::exception();
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}
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virtual ~HdfsEnv() {
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}
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virtual Status NewSequentialFile(const std::string& fname,
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SequentialFile** result);
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virtual Status NewRandomAccessFile(const std::string& fname,
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RandomAccessFile** result) {}
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virtual Status NewWritableFile(const std::string& fname,
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WritableFile** result){}
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virtual bool FileExists(const std::string& fname){}
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virtual Status GetChildren(const std::string& path,
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std::vector<std::string>* result){}
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virtual Status DeleteFile(const std::string& fname){}
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virtual Status CreateDir(const std::string& name){}
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virtual Status DeleteDir(const std::string& name){}
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virtual Status GetFileSize(const std::string& fname, uint64_t* size){}
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virtual Status RenameFile(const std::string& src, const std::string& target){}
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virtual Status LockFile(const std::string& fname, FileLock** lock){}
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virtual Status UnlockFile(FileLock* lock){}
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virtual Status NewLogger(const std::string& fname, Logger** result){}
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virtual void Schedule( void (*function)(void* arg), void* arg) {}
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virtual void StartThread(void (*function)(void* arg), void* arg) {}
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virtual Status GetTestDirectory(std::string* path) {}
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virtual uint64_t NowMicros() {}
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virtual void SleepForMicroseconds(int micros) {}
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};
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}
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#endif // USE_HDFS
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#endif // LEVELDB_HDFS_FILE_H
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