491 lines
17 KiB
C
491 lines
17 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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#ifndef LIBHDFS_HDFS_H
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#define LIBHDFS_HDFS_H
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#include <sys/types.h>
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#include <sys/stat.h>
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#include <fcntl.h>
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#include <stdio.h>
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#include <stdint.h>
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#include <string.h>
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#include <stdlib.h>
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#include <time.h>
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#include <errno.h>
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#include <jni.h>
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#ifndef O_RDONLY
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#define O_RDONLY 1
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#endif
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#ifndef O_WRONLY
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#define O_WRONLY 2
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#endif
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#ifndef EINTERNAL
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#define EINTERNAL 255
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#endif
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/** All APIs set errno to meaningful values */
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#ifdef __cplusplus
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extern "C" {
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#endif
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/**
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* Some utility decls used in libhdfs.
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*/
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typedef int32_t tSize; /// size of data for read/write io ops
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typedef time_t tTime; /// time type in seconds
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typedef int64_t tOffset;/// offset within the file
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typedef uint16_t tPort; /// port
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typedef enum tObjectKind {
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kObjectKindFile = 'F',
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kObjectKindDirectory = 'D',
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} tObjectKind;
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/**
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* The C reflection of org.apache.org.hadoop.FileSystem .
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*/
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typedef void* hdfsFS;
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/**
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* The C equivalent of org.apache.org.hadoop.FSData(Input|Output)Stream .
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*/
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enum hdfsStreamType
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{
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UNINITIALIZED = 0,
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INPUT = 1,
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OUTPUT = 2,
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};
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/**
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* The 'file-handle' to a file in hdfs.
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*/
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struct hdfsFile_internal {
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void* file;
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enum hdfsStreamType type;
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};
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typedef struct hdfsFile_internal* hdfsFile;
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/**
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* hdfsConnectAsUser - Connect to a hdfs file system as a specific user
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* Connect to the hdfs.
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* @param host A string containing either a host name, or an ip address
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* of the namenode of a hdfs cluster. 'host' should be passed as NULL if
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* you want to connect to local filesystem. 'host' should be passed as
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* 'default' (and port as 0) to used the 'configured' filesystem
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* (core-site/core-default.xml).
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* @param port The port on which the server is listening.
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* @param user the user name (this is hadoop domain user). Or NULL is equivelant to hhdfsConnect(host, port)
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* @param groups the groups (these are hadoop domain groups)
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* @return Returns a handle to the filesystem or NULL on error.
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*/
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hdfsFS hdfsConnectAsUser(const char* host, tPort port, const char *user , const char *groups[], int groups_size );
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/**
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* hdfsConnect - Connect to a hdfs file system.
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* Connect to the hdfs.
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* @param host A string containing either a host name, or an ip address
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* of the namenode of a hdfs cluster. 'host' should be passed as NULL if
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* you want to connect to local filesystem. 'host' should be passed as
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* 'default' (and port as 0) to used the 'configured' filesystem
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* (core-site/core-default.xml).
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* @param port The port on which the server is listening.
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* @return Returns a handle to the filesystem or NULL on error.
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*/
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hdfsFS hdfsConnect(const char* host, tPort port);
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/**
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* This are the same as hdfsConnectAsUser except that every invocation returns a new FileSystem handle.
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* Applications should call a hdfsDisconnect for every call to hdfsConnectAsUserNewInstance.
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*/
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hdfsFS hdfsConnectAsUserNewInstance(const char* host, tPort port, const char *user , const char *groups[], int groups_size );
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hdfsFS hdfsConnectNewInstance(const char* host, tPort port);
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hdfsFS hdfsConnectPath(const char* uri);
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/**
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* hdfsDisconnect - Disconnect from the hdfs file system.
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* Disconnect from hdfs.
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* @param fs The configured filesystem handle.
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* @return Returns 0 on success, -1 on error.
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*/
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int hdfsDisconnect(hdfsFS fs);
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/**
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* hdfsOpenFile - Open a hdfs file in given mode.
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* @param fs The configured filesystem handle.
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* @param path The full path to the file.
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* @param flags - an | of bits/fcntl.h file flags - supported flags are O_RDONLY, O_WRONLY (meaning create or overwrite i.e., implies O_TRUNCAT),
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* O_WRONLY|O_APPEND. Other flags are generally ignored other than (O_RDWR || (O_EXCL & O_CREAT)) which return NULL and set errno equal ENOTSUP.
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* @param bufferSize Size of buffer for read/write - pass 0 if you want
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* to use the default configured values.
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* @param replication Block replication - pass 0 if you want to use
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* the default configured values.
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* @param blocksize Size of block - pass 0 if you want to use the
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* default configured values.
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* @return Returns the handle to the open file or NULL on error.
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*/
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hdfsFile hdfsOpenFile(hdfsFS fs, const char* path, int flags,
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int bufferSize, short replication, tSize blocksize);
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/**
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* hdfsCloseFile - Close an open file.
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* @param fs The configured filesystem handle.
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* @param file The file handle.
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* @return Returns 0 on success, -1 on error.
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*/
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int hdfsCloseFile(hdfsFS fs, hdfsFile file);
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/**
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* hdfsExists - Checks if a given path exsits on the filesystem
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* @param fs The configured filesystem handle.
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* @param path The path to look for
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* @return Returns 0 on exists, 1 on non-exists, -1/-2 on error.
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*/
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int hdfsExists(hdfsFS fs, const char *path);
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/**
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* hdfsSeek - Seek to given offset in file.
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* This works only for files opened in read-only mode.
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* @param fs The configured filesystem handle.
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* @param file The file handle.
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* @param desiredPos Offset into the file to seek into.
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* @return Returns 0 on success, -1 on error.
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*/
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int hdfsSeek(hdfsFS fs, hdfsFile file, tOffset desiredPos);
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/**
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* hdfsTell - Get the current offset in the file, in bytes.
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* @param fs The configured filesystem handle.
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* @param file The file handle.
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* @return Current offset, -1 on error.
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*/
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tOffset hdfsTell(hdfsFS fs, hdfsFile file);
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/**
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* hdfsRead - Read data from an open file.
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* @param fs The configured filesystem handle.
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* @param file The file handle.
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* @param buffer The buffer to copy read bytes into.
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* @param length The length of the buffer.
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* @return Returns the number of bytes actually read, possibly less
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* than than length;-1 on error.
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*/
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tSize hdfsRead(hdfsFS fs, hdfsFile file, void* buffer, tSize length);
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/**
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* hdfsPread - Positional read of data from an open file.
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* @param fs The configured filesystem handle.
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* @param file The file handle.
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* @param position Position from which to read
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* @param buffer The buffer to copy read bytes into.
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* @param length The length of the buffer.
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* @return Returns the number of bytes actually read, possibly less than
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* than length;-1 on error.
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*/
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tSize hdfsPread(hdfsFS fs, hdfsFile file, tOffset position,
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void* buffer, tSize length);
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/**
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* hdfsWrite - Write data into an open file.
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* @param fs The configured filesystem handle.
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* @param file The file handle.
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* @param buffer The data.
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* @param length The no. of bytes to write.
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* @return Returns the number of bytes written, -1 on error.
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*/
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tSize hdfsWrite(hdfsFS fs, hdfsFile file, const void* buffer,
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tSize length);
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/**
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* hdfsWrite - Flush the data.
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* @param fs The configured filesystem handle.
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* @param file The file handle.
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* @return Returns 0 on success, -1 on error.
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*/
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int hdfsFlush(hdfsFS fs, hdfsFile file);
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/**
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* hdfsSync - Sync the data to persistent store.
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* @param fs The configured filesystem handle.
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* @param file The file handle.
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* @return Returns 0 on success, -1 on error.
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*/
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int hdfsSync(hdfsFS fs, hdfsFile file);
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/**
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* hdfsGetNumReplicasInPipeline - get number of remaining replicas in
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* pipeline
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* @param fs The configured filesystem handle
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* @param file the file handle
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* @return returns the # of datanodes in the write pipeline; -1 on error
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*/
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int hdfsGetNumCurrentReplicas(hdfsFS, hdfsFile file);
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/**
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* hdfsAvailable - Number of bytes that can be read from this
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* input stream without blocking.
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* @param fs The configured filesystem handle.
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* @param file The file handle.
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* @return Returns available bytes; -1 on error.
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*/
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int hdfsAvailable(hdfsFS fs, hdfsFile file);
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/**
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* hdfsCopy - Copy file from one filesystem to another.
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* @param srcFS The handle to source filesystem.
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* @param src The path of source file.
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* @param dstFS The handle to destination filesystem.
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* @param dst The path of destination file.
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* @return Returns 0 on success, -1 on error.
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*/
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int hdfsCopy(hdfsFS srcFS, const char* src, hdfsFS dstFS, const char* dst);
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/**
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* hdfsMove - Move file from one filesystem to another.
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* @param srcFS The handle to source filesystem.
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* @param src The path of source file.
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* @param dstFS The handle to destination filesystem.
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* @param dst The path of destination file.
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* @return Returns 0 on success, -1 on error.
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*/
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int hdfsMove(hdfsFS srcFS, const char* src, hdfsFS dstFS, const char* dst);
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/**
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* hdfsDelete - Delete file.
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* @param fs The configured filesystem handle.
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* @param path The path of the file.
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* @return Returns 0 on success, -1 on error.
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*/
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int hdfsDelete(hdfsFS fs, const char* path);
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/**
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* hdfsRename - Rename file.
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* @param fs The configured filesystem handle.
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* @param oldPath The path of the source file.
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* @param newPath The path of the destination file.
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* @return Returns 0 on success, -1 on error.
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*/
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int hdfsRename(hdfsFS fs, const char* oldPath, const char* newPath);
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/**
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* hdfsGetWorkingDirectory - Get the current working directory for
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* the given filesystem.
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* @param fs The configured filesystem handle.
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* @param buffer The user-buffer to copy path of cwd into.
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* @param bufferSize The length of user-buffer.
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* @return Returns buffer, NULL on error.
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*/
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char* hdfsGetWorkingDirectory(hdfsFS fs, char *buffer, size_t bufferSize);
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/**
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* hdfsSetWorkingDirectory - Set the working directory. All relative
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* paths will be resolved relative to it.
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* @param fs The configured filesystem handle.
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* @param path The path of the new 'cwd'.
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* @return Returns 0 on success, -1 on error.
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*/
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int hdfsSetWorkingDirectory(hdfsFS fs, const char* path);
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/**
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* hdfsCreateDirectory - Make the given file and all non-existent
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* parents into directories.
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* @param fs The configured filesystem handle.
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* @param path The path of the directory.
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* @return Returns 0 on success, -1 on error.
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*/
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int hdfsCreateDirectory(hdfsFS fs, const char* path);
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/**
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* hdfsSetReplication - Set the replication of the specified
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* file to the supplied value
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* @param fs The configured filesystem handle.
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* @param path The path of the file.
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* @return Returns 0 on success, -1 on error.
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*/
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int hdfsSetReplication(hdfsFS fs, const char* path, int16_t replication);
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/**
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* hdfsFileInfo - Information about a file/directory.
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*/
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typedef struct {
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tObjectKind mKind; /* file or directory */
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char *mName; /* the name of the file */
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tTime mLastMod; /* the last modification time for the file in seconds */
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tOffset mSize; /* the size of the file in bytes */
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short mReplication; /* the count of replicas */
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tOffset mBlockSize; /* the block size for the file */
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char *mOwner; /* the owner of the file */
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char *mGroup; /* the group associated with the file */
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short mPermissions; /* the permissions associated with the file */
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tTime mLastAccess; /* the last access time for the file in seconds */
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} hdfsFileInfo;
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/**
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* hdfsListDirectory - Get list of files/directories for a given
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* directory-path. hdfsFreeFileInfo should be called to deallocate memory if
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* the function returns non-NULL value.
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* @param fs The configured filesystem handle.
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* @param path The path of the directory.
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* @param numEntries Set to the number of files/directories in path.
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* @return Returns a dynamically-allocated array of hdfsFileInfo
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* objects; NULL if empty or on error.
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* on error, numEntries will be -1.
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*/
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hdfsFileInfo *hdfsListDirectory(hdfsFS fs, const char* path,
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int *numEntries);
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/**
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* hdfsGetPathInfo - Get information about a path as a (dynamically
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* allocated) single hdfsFileInfo struct. hdfsFreeFileInfo should be
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* called when the pointer is no longer needed.
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* @param fs The configured filesystem handle.
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* @param path The path of the file.
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* @return Returns a dynamically-allocated hdfsFileInfo object;
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* NULL on error.
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*/
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hdfsFileInfo *hdfsGetPathInfo(hdfsFS fs, const char* path);
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/**
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* hdfsFreeFileInfo - Free up the hdfsFileInfo array (including fields)
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* @param hdfsFileInfo The array of dynamically-allocated hdfsFileInfo
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* objects.
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* @param numEntries The size of the array.
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*/
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void hdfsFreeFileInfo(hdfsFileInfo *hdfsFileInfo, int numEntries);
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/**
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* hdfsGetHosts - Get hostnames where a particular block (determined by
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* pos & blocksize) of a file is stored. The last element in the array
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* is NULL. Due to replication, a single block could be present on
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* multiple hosts.
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* @param fs The configured filesystem handle.
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* @param path The path of the file.
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* @param start The start of the block.
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* @param length The length of the block.
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* @return Returns a dynamically-allocated 2-d array of blocks-hosts;
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* NULL on error.
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*/
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char*** hdfsGetHosts(hdfsFS fs, const char* path,
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tOffset start, tOffset length);
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/**
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* hdfsFreeHosts - Free up the structure returned by hdfsGetHosts
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* @param hdfsFileInfo The array of dynamically-allocated hdfsFileInfo
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* objects.
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* @param numEntries The size of the array.
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*/
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void hdfsFreeHosts(char ***blockHosts);
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/**
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* hdfsGetDefaultBlockSize - Get the optimum blocksize.
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* @param fs The configured filesystem handle.
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* @return Returns the blocksize; -1 on error.
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*/
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tOffset hdfsGetDefaultBlockSize(hdfsFS fs);
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/**
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* hdfsGetCapacity - Return the raw capacity of the filesystem.
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* @param fs The configured filesystem handle.
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* @return Returns the raw-capacity; -1 on error.
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*/
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tOffset hdfsGetCapacity(hdfsFS fs);
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/**
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* hdfsGetUsed - Return the total raw size of all files in the filesystem.
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* @param fs The configured filesystem handle.
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* @return Returns the total-size; -1 on error.
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*/
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tOffset hdfsGetUsed(hdfsFS fs);
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/**
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* hdfsChown
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* @param fs The configured filesystem handle.
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* @param path the path to the file or directory
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* @param owner this is a string in Hadoop land. Set to null or "" if only setting group
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* @param group this is a string in Hadoop land. Set to null or "" if only setting user
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* @return 0 on success else -1
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*/
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int hdfsChown(hdfsFS fs, const char* path, const char *owner, const char *group);
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/**
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* hdfsChmod
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* @param fs The configured filesystem handle.
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* @param path the path to the file or directory
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* @param mode the bitmask to set it to
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* @return 0 on success else -1
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*/
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int hdfsChmod(hdfsFS fs, const char* path, short mode);
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/**
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* hdfsUtime
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* @param fs The configured filesystem handle.
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* @param path the path to the file or directory
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* @param mtime new modification time or 0 for only set access time in seconds
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* @param atime new access time or 0 for only set modification time in seconds
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* @return 0 on success else -1
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*/
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int hdfsUtime(hdfsFS fs, const char* path, tTime mtime, tTime atime);
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#ifdef __cplusplus
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}
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#endif
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#endif /*LIBHDFS_HDFS_H*/
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/**
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* vim: ts=4: sw=4: et
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*/
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