Module com.aoapps.io.filesystems.posix

Package com.aoapps.io.filesystems.posix

Class DedupPosixFileSystem

java.lang.Object

com.aoapps.io.filesystems.FileSystemWrapper

com.aoapps.io.filesystems.posix.DedupPosixFileSystem

All Implemented Interfaces:

FileSystem, PosixFileSystem

public class DedupPosixFileSystem
extends FileSystemWrapper
implements PosixFileSystem

De-duplicates data chunks on the fly.

 real name (empty file, small file, or possible full/partially restored large file)
 <A<O<DEDUP>O>A>_# → symbolic linked to real name
 <A<O<DEDUP>O>A>_#_chunk#_md5_size[.gz] → hard linked to index
 

Renaming a file requires to rename both the file and the one symbolic link to the file.

Files smaller than TODO bytes in length will not be deduped. This is because the overhead of deduping is:

1. TODO

Author:

AO Industries, Inc.

Nested Class Summary

Nested classes/interfaces inherited from class com.aoapps.io.filesystems.FileSystemWrapper

FileSystemWrapper.PathIteratorWrapper, FileSystemWrapper.PathWrapper

Field Summary

Fields inherited from class com.aoapps.io.filesystems.FileSystemWrapper

wrappedFileSystem

Constructor Summary

Constructors

Constructor	Description
DedupPosixFileSystem(PosixFileSystem wrapped)

Method Summary

Modifier and Type	Method	Description
Path	createDirectory(Path path, int mode)	Delegates to the wrapped file system.
Path	createFile(Path path)
Path	createFile(Path path, int mode)	Atomically creates an empty file (must not have already existed) with the given permissions.
Stat	stat(Path path)	Delegates to the wrapped file system.

Methods inherited from class com.aoapps.io.filesystems.FileSystemWrapper

checkSubPath, createDirectory, delete, join, list, lock, parsePath, size, unwrapPath, wrapPath, wrapSubPath

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Methods inherited from interface com.aoapps.io.filesystems.FileSystem

createDirectory, delete, join, list, lock, parsePath, size

Methods inherited from interface com.aoapps.io.filesystems.posix.PosixFileSystem

checkSubPath

Constructor Details

DedupPosixFileSystem

public DedupPosixFileSystem(PosixFileSystem wrapped)

Method Details

stat

public Stat stat(Path path)
          throws IOException

Delegates to the wrapped file system.

Specified by:

stat in interface PosixFileSystem

Parameters:

path - Must be from this file system.

Throws:

IOException

createFile

public Path createFile(Path path)
                throws IOException

Specified by:

createFile in interface FileSystem

Overrides:

createFile in class FileSystemWrapper

Throws:

IOException

createFile

public Path createFile(Path path,
 int mode)
                throws IOException

Description copied from interface: PosixFileSystem

Atomically creates an empty file (must not have already existed) with the given permissions.

Specified by:

createFile in interface PosixFileSystem

Returns:

returns the path

Throws:

IOException - if an underlying I/O error occurs.

createDirectory

public Path createDirectory(Path path,
 int mode)
                     throws IOException

Delegates to the wrapped file system.

Specified by:

createDirectory in interface PosixFileSystem

Returns:

returns the path

Throws:

IOException - if an underlying I/O error occurs.