hdfs.h
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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
- *
- * http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
- #ifndef LIBHDFS_HDFS_H
- #define LIBHDFS_HDFS_H
- #include <sys/types.h>
- #include <sys/stat.h>
- #include <fcntl.h>
- #include <stdio.h>
- #include <stdint.h>
- #include <string.h>
- #include <stdlib.h>
- #include <time.h>
- #include <errno.h>
- #include <jni.h>
- #ifndef O_RDONLY
- #define O_RDONLY 1
- #endif
- #ifndef O_WRONLY
- #define O_WRONLY 2
- #endif
- #ifndef EINTERNAL
- #define EINTERNAL 255
- #endif
- /** All APIs set errno to meaningful values */
- #ifdef __cplusplus
- extern "C" {
- #endif
- /**
- * Some utility decls used in libhdfs.
- */
- typedef int32_t tSize; /// size of data for read/write io ops
- typedef time_t tTime; /// time type in seconds
- typedef int64_t tOffset;/// offset within the file
- typedef uint16_t tPort; /// port
- typedef enum tObjectKind {
- kObjectKindFile = 'F',
- kObjectKindDirectory = 'D',
- } tObjectKind;
- /**
- * The C reflection of org.apache.org.hadoop.FileSystem .
- */
- typedef void* hdfsFS;
-
- /**
- * The C equivalent of org.apache.org.hadoop.FSData(Input|Output)Stream .
- */
- enum hdfsStreamType
- {
- UNINITIALIZED = 0,
- INPUT = 1,
- OUTPUT = 2,
- };
-
- /**
- * The 'file-handle' to a file in hdfs.
- */
- struct hdfsFile_internal {
- void* file;
- enum hdfsStreamType type;
- };
- typedef struct hdfsFile_internal* hdfsFile;
-
- /**
- * hdfsConnectAsUser - Connect to a hdfs file system as a specific user
- * Connect to the hdfs.
- * @param host A string containing either a host name, or an ip address
- * of the namenode of a hdfs cluster. 'host' should be passed as NULL if
- * you want to connect to local filesystem. 'host' should be passed as
- * 'default' (and port as 0) to used the 'configured' filesystem
- * (core-site/core-default.xml).
- * @param port The port on which the server is listening.
- * @param user the user name (this is hadoop domain user). Or NULL is equivelant to hhdfsConnect(host, port)
- * @param groups the groups (these are hadoop domain groups)
- * @return Returns a handle to the filesystem or NULL on error.
- */
- hdfsFS hdfsConnectAsUser(const char* host, tPort port, const char *user , const char *groups[], int groups_size );
- /**
- * hdfsConnect - Connect to a hdfs file system.
- * Connect to the hdfs.
- * @param host A string containing either a host name, or an ip address
- * of the namenode of a hdfs cluster. 'host' should be passed as NULL if
- * you want to connect to local filesystem. 'host' should be passed as
- * 'default' (and port as 0) to used the 'configured' filesystem
- * (core-site/core-default.xml).
- * @param port The port on which the server is listening.
- * @return Returns a handle to the filesystem or NULL on error.
- */
- hdfsFS hdfsConnect(const char* host, tPort port);
- /**
- * hdfsDisconnect - Disconnect from the hdfs file system.
- * Disconnect from hdfs.
- * @param fs The configured filesystem handle.
- * @return Returns 0 on success, -1 on error.
- */
- int hdfsDisconnect(hdfsFS fs);
-
- /**
- * hdfsOpenFile - Open a hdfs file in given mode.
- * @param fs The configured filesystem handle.
- * @param path The full path to the file.
- * @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),
- * 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.
- * @param bufferSize Size of buffer for read/write - pass 0 if you want
- * to use the default configured values.
- * @param replication Block replication - pass 0 if you want to use
- * the default configured values.
- * @param blocksize Size of block - pass 0 if you want to use the
- * default configured values.
- * @return Returns the handle to the open file or NULL on error.
- */
- hdfsFile hdfsOpenFile(hdfsFS fs, const char* path, int flags,
- int bufferSize, short replication, tSize blocksize);
- /**
- * hdfsCloseFile - Close an open file.
- * @param fs The configured filesystem handle.
- * @param file The file handle.
- * @return Returns 0 on success, -1 on error.
- */
- int hdfsCloseFile(hdfsFS fs, hdfsFile file);
- /**
- * hdfsExists - Checks if a given path exsits on the filesystem
- * @param fs The configured filesystem handle.
- * @param path The path to look for
- * @return Returns 0 on success, -1 on error.
- */
- int hdfsExists(hdfsFS fs, const char *path);
- /**
- * hdfsSeek - Seek to given offset in file.
- * This works only for files opened in read-only mode.
- * @param fs The configured filesystem handle.
- * @param file The file handle.
- * @param desiredPos Offset into the file to seek into.
- * @return Returns 0 on success, -1 on error.
- */
- int hdfsSeek(hdfsFS fs, hdfsFile file, tOffset desiredPos);
- /**
- * hdfsTell - Get the current offset in the file, in bytes.
- * @param fs The configured filesystem handle.
- * @param file The file handle.
- * @return Current offset, -1 on error.
- */
- tOffset hdfsTell(hdfsFS fs, hdfsFile file);
- /**
- * hdfsRead - Read data from an open file.
- * @param fs The configured filesystem handle.
- * @param file The file handle.
- * @param buffer The buffer to copy read bytes into.
- * @param length The length of the buffer.
- * @return Returns the number of bytes actually read, possibly less
- * than than length;-1 on error.
- */
- tSize hdfsRead(hdfsFS fs, hdfsFile file, void* buffer, tSize length);
- /**
- * hdfsPread - Positional read of data from an open file.
- * @param fs The configured filesystem handle.
- * @param file The file handle.
- * @param position Position from which to read
- * @param buffer The buffer to copy read bytes into.
- * @param length The length of the buffer.
- * @return Returns the number of bytes actually read, possibly less than
- * than length;-1 on error.
- */
- tSize hdfsPread(hdfsFS fs, hdfsFile file, tOffset position,
- void* buffer, tSize length);
- /**
- * hdfsWrite - Write data into an open file.
- * @param fs The configured filesystem handle.
- * @param file The file handle.
- * @param buffer The data.
- * @param length The no. of bytes to write.
- * @return Returns the number of bytes written, -1 on error.
- */
- tSize hdfsWrite(hdfsFS fs, hdfsFile file, const void* buffer,
- tSize length);
- /**
- * hdfsWrite - Flush the data.
- * @param fs The configured filesystem handle.
- * @param file The file handle.
- * @return Returns 0 on success, -1 on error.
- */
- int hdfsFlush(hdfsFS fs, hdfsFile file);
- /**
- * hdfsAvailable - Number of bytes that can be read from this
- * input stream without blocking.
- * @param fs The configured filesystem handle.
- * @param file The file handle.
- * @return Returns available bytes; -1 on error.
- */
- int hdfsAvailable(hdfsFS fs, hdfsFile file);
- /**
- * hdfsCopy - Copy file from one filesystem to another.
- * @param srcFS The handle to source filesystem.
- * @param src The path of source file.
- * @param dstFS The handle to destination filesystem.
- * @param dst The path of destination file.
- * @return Returns 0 on success, -1 on error.
- */
- int hdfsCopy(hdfsFS srcFS, const char* src, hdfsFS dstFS, const char* dst);
- /**
- * hdfsMove - Move file from one filesystem to another.
- * @param srcFS The handle to source filesystem.
- * @param src The path of source file.
- * @param dstFS The handle to destination filesystem.
- * @param dst The path of destination file.
- * @return Returns 0 on success, -1 on error.
- */
- int hdfsMove(hdfsFS srcFS, const char* src, hdfsFS dstFS, const char* dst);
- /**
- * hdfsDelete - Delete file.
- * @param fs The configured filesystem handle.
- * @param path The path of the file.
- * @return Returns 0 on success, -1 on error.
- */
- int hdfsDelete(hdfsFS fs, const char* path);
- /**
- * hdfsRename - Rename file.
- * @param fs The configured filesystem handle.
- * @param oldPath The path of the source file.
- * @param newPath The path of the destination file.
- * @return Returns 0 on success, -1 on error.
- */
- int hdfsRename(hdfsFS fs, const char* oldPath, const char* newPath);
- /**
- * hdfsGetWorkingDirectory - Get the current working directory for
- * the given filesystem.
- * @param fs The configured filesystem handle.
- * @param buffer The user-buffer to copy path of cwd into.
- * @param bufferSize The length of user-buffer.
- * @return Returns buffer, NULL on error.
- */
- char* hdfsGetWorkingDirectory(hdfsFS fs, char *buffer, size_t bufferSize);
- /**
- * hdfsSetWorkingDirectory - Set the working directory. All relative
- * paths will be resolved relative to it.
- * @param fs The configured filesystem handle.
- * @param path The path of the new 'cwd'.
- * @return Returns 0 on success, -1 on error.
- */
- int hdfsSetWorkingDirectory(hdfsFS fs, const char* path);
- /**
- * hdfsCreateDirectory - Make the given file and all non-existent
- * parents into directories.
- * @param fs The configured filesystem handle.
- * @param path The path of the directory.
- * @return Returns 0 on success, -1 on error.
- */
- int hdfsCreateDirectory(hdfsFS fs, const char* path);
- /**
- * hdfsSetReplication - Set the replication of the specified
- * file to the supplied value
- * @param fs The configured filesystem handle.
- * @param path The path of the file.
- * @return Returns 0 on success, -1 on error.
- */
- int hdfsSetReplication(hdfsFS fs, const char* path, int16_t replication);
- /**
- * hdfsFileInfo - Information about a file/directory.
- */
- typedef struct {
- tObjectKind mKind; /* file or directory */
- char *mName; /* the name of the file */
- tTime mLastMod; /* the last modification time for the file in seconds */
- tOffset mSize; /* the size of the file in bytes */
- short mReplication; /* the count of replicas */
- tOffset mBlockSize; /* the block size for the file */
- char *mOwner; /* the owner of the file */
- char *mGroup; /* the group associated with the file */
- short mPermissions; /* the permissions associated with the file */
- tTime mLastAccess; /* the last access time for the file in seconds */
- } hdfsFileInfo;
- /**
- * hdfsListDirectory - Get list of files/directories for a given
- * directory-path. hdfsFreeFileInfo should be called to deallocate memory.
- * @param fs The configured filesystem handle.
- * @param path The path of the directory.
- * @param numEntries Set to the number of files/directories in path.
- * @return Returns a dynamically-allocated array of hdfsFileInfo
- * objects; NULL on error.
- */
- hdfsFileInfo *hdfsListDirectory(hdfsFS fs, const char* path,
- int *numEntries);
- /**
- * hdfsGetPathInfo - Get information about a path as a (dynamically
- * allocated) single hdfsFileInfo struct. hdfsFreeFileInfo should be
- * called when the pointer is no longer needed.
- * @param fs The configured filesystem handle.
- * @param path The path of the file.
- * @return Returns a dynamically-allocated hdfsFileInfo object;
- * NULL on error.
- */
- hdfsFileInfo *hdfsGetPathInfo(hdfsFS fs, const char* path);
- /**
- * hdfsFreeFileInfo - Free up the hdfsFileInfo array (including fields)
- * @param hdfsFileInfo The array of dynamically-allocated hdfsFileInfo
- * objects.
- * @param numEntries The size of the array.
- */
- void hdfsFreeFileInfo(hdfsFileInfo *hdfsFileInfo, int numEntries);
- /**
- * hdfsGetHosts - Get hostnames where a particular block (determined by
- * pos & blocksize) of a file is stored. The last element in the array
- * is NULL. Due to replication, a single block could be present on
- * multiple hosts.
- * @param fs The configured filesystem handle.
- * @param path The path of the file.
- * @param start The start of the block.
- * @param length The length of the block.
- * @return Returns a dynamically-allocated 2-d array of blocks-hosts;
- * NULL on error.
- */
- char*** hdfsGetHosts(hdfsFS fs, const char* path,
- tOffset start, tOffset length);
- /**
- * hdfsFreeHosts - Free up the structure returned by hdfsGetHosts
- * @param hdfsFileInfo The array of dynamically-allocated hdfsFileInfo
- * objects.
- * @param numEntries The size of the array.
- */
- void hdfsFreeHosts(char ***blockHosts);
- /**
- * hdfsGetDefaultBlockSize - Get the optimum blocksize.
- * @param fs The configured filesystem handle.
- * @return Returns the blocksize; -1 on error.
- */
- tOffset hdfsGetDefaultBlockSize(hdfsFS fs);
- /**
- * hdfsGetCapacity - Return the raw capacity of the filesystem.
- * @param fs The configured filesystem handle.
- * @return Returns the raw-capacity; -1 on error.
- */
- tOffset hdfsGetCapacity(hdfsFS fs);
- /**
- * hdfsGetUsed - Return the total raw size of all files in the filesystem.
- * @param fs The configured filesystem handle.
- * @return Returns the total-size; -1 on error.
- */
- tOffset hdfsGetUsed(hdfsFS fs);
- /**
- * hdfsChown
- * @param fs The configured filesystem handle.
- * @param path the path to the file or directory
- * @param owner this is a string in Hadoop land. Set to null or "" if only setting group
- * @param group this is a string in Hadoop land. Set to null or "" if only setting user
- * @return 0 on success else -1
- */
- int hdfsChown(hdfsFS fs, const char* path, const char *owner, const char *group);
- /**
- * hdfsChmod
- * @param fs The configured filesystem handle.
- * @param path the path to the file or directory
- * @param mode the bitmask to set it to
- * @return 0 on success else -1
- */
- int hdfsChmod(hdfsFS fs, const char* path, short mode);
- /**
- * hdfsUtime
- * @param fs The configured filesystem handle.
- * @param path the path to the file or directory
- * @param mtime new modification time or 0 for only set access time in seconds
- * @param atime new access time or 0 for only set modification time in seconds
- * @return 0 on success else -1
- */
- int hdfsUtime(hdfsFS fs, const char* path, tTime mtime, tTime atime);
-
- #ifdef __cplusplus
- }
- #endif
- #endif /*LIBHDFS_HDFS_H*/
- /**
- * vim: ts=4: sw=4: et
- */