freenet.support.io

Class FileBucket

java.lang.Object

freenet.support.io.BaseFileBucket

freenet.support.io.FileBucket

All Implemented Interfaces:

Bucket, RandomAccessBucket, java.io.Serializable

public class FileBucket
extends BaseFileBucket
implements Bucket, java.io.Serializable

A file Bucket is an implementation of Bucket that writes to a file.

See Also:

Serialized Form

Field Summary

Fields

Modifier and Type	Field and Description
protected boolean	createFileOnly
protected boolean	deleteOnExit
protected boolean	deleteOnFree
protected java.io.File	file
static int	MAGIC
protected boolean	readOnly

Fields inherited from class freenet.support.io.BaseFileBucket

fileRestartCounter, tempDir

Constructor Summary

Constructors

Modifier	Constructor and Description
protected	FileBucket()
protected	FileBucket(java.io.DataInputStream dis)
	FileBucket(java.io.File file, boolean readOnly, boolean createFileOnly, boolean deleteOnExit, boolean deleteOnFree) Creates a new FileBucket.

Method Summary

Modifier and Type	Method and Description
protected boolean	createFileOnly() If true, we will fail if the file already exist.
RandomAccessBucket	createShadow() Create a shallow read-only copy of this bucket, using different objects but using the same external storage.
protected boolean	deleteOnExit()
protected boolean	deleteOnFree()
boolean	equals(java.lang.Object obj)
java.io.File	getFile() Returns the file object this buckets data is kept in.
int	hashCode()
boolean	isReadOnly() Is the bucket read-only?
void	onResume(ClientContext context) Called after restarting.
void	setReadOnly() Make the bucket read-only.
void	storeTo(java.io.DataOutputStream dos) Write enough data to reconstruct the Bucket, or throw UnsupportedOperationException.
protected boolean	tempFileAlreadyExists() If true, then the file is temporary and must already exist, so we will just open it.

Methods inherited from class freenet.support.io.BaseFileBucket

deleteFile, free, free, getInputStream, getInputStreamUnbuffered, getName, getOutputStream, getOutputStreamUnbuffered, getPersistentTempID, getTempDir, getTempfile, setDeleteOnExit, setTempDir, size, split, toRandomAccessBuffer, toString

Methods inherited from class java.lang.Object

clone, finalize, getClass, notify, notifyAll, wait, wait, wait

Methods inherited from interface freenet.support.api.Bucket

free, getInputStream, getInputStreamUnbuffered, getName, getOutputStream, getOutputStreamUnbuffered, size

Field Detail

file

protected final java.io.File file

readOnly

protected boolean readOnly

deleteOnFree

protected boolean deleteOnFree

deleteOnExit

protected final boolean deleteOnExit

createFileOnly

protected final boolean createFileOnly

MAGIC

public static final int MAGIC

See Also:

Constant Field Values

Constructor Detail

FileBucket

public FileBucket(java.io.File file,
                  boolean readOnly,
                  boolean createFileOnly,
                  boolean deleteOnExit,
                  boolean deleteOnFree)

Creates a new FileBucket.

Parameters:

file - The File to read and write to.

readOnly - If true, any attempt to write to the bucket will result in an IOException. Can be set later. Irreversible. @see isReadOnly(), setReadOnly()

createFileOnly - If true, create the file if it doesn't exist, but if it does exist, throw a FileExistsException on any write operation. This is safe against symlink attacks because we write to a temp file and then rename. It is technically possible that the rename will clobber an existing file if there is a race condition, but since it will not write over a symlink this is probably not dangerous. User-supplied filenames should in any case be restricted by higher levels.

deleteOnExit - If true, delete the file on a clean exit of the JVM. Irreversible - use with care!

deleteOnFree - If true, delete the file on finalization. Reversible.

FileBucket

protected FileBucket()

FileBucket

protected FileBucket(java.io.DataInputStream dis)
              throws java.io.IOException,
                     StorageFormatException

Throws:

java.io.IOException

StorageFormatException

Method Detail

getFile

public java.io.File getFile()

Returns the file object this buckets data is kept in.

Specified by:

getFile in class BaseFileBucket

isReadOnly

public boolean isReadOnly()

Description copied from interface: Bucket

Is the bucket read-only?

Specified by:

isReadOnly in interface Bucket

setReadOnly

public void setReadOnly()

Description copied from interface: Bucket

Make the bucket read-only. Irreversible.

Specified by:

setReadOnly in interface Bucket

createFileOnly

protected boolean createFileOnly()

Description copied from class: BaseFileBucket

If true, we will fail if the file already exist. Incompatible with tempFileAlreadyExists()!

Specified by:

createFileOnly in class BaseFileBucket

deleteOnExit

protected boolean deleteOnExit()

Specified by:

deleteOnExit in class BaseFileBucket

deleteOnFree

protected boolean deleteOnFree()

Specified by:

deleteOnFree in class BaseFileBucket

createShadow

public RandomAccessBucket createShadow()

Description copied from interface: Bucket

Create a shallow read-only copy of this bucket, using different objects but using the same external storage. If this is not possible, return null. Note that if the underlying bucket is deleted, the copy will become invalid and probably throw an IOException on read, or possibly return too-short data etc. In some use cases e.g. on fproxy, this is acceptable.

Specified by:

createShadow in interface Bucket

Specified by:

createShadow in interface RandomAccessBucket

onResume

public void onResume(ClientContext context)
              throws ResumeFailedException

Description copied from interface: Bucket

Called after restarting. The Bucket should do any necessary housekeeping after resuming, e.g. registering itself with the appropriate persistent bucket tracker to avoid being garbage-collected. May be called twice, so the Bucket may need to track this internally.

Specified by:

onResume in interface Bucket

Overrides:

onResume in class BaseFileBucket

Parameters:

context - All the necessary runtime support will be on this object.

Throws:

ResumeFailedException

tempFileAlreadyExists

protected boolean tempFileAlreadyExists()

Description copied from class: BaseFileBucket

If true, then the file is temporary and must already exist, so we will just open it. Otherwise we will create a temporary file and then rename it over the target. Incompatible with createFileOnly()!

Specified by:

tempFileAlreadyExists in class BaseFileBucket

storeTo

public void storeTo(java.io.DataOutputStream dos)
             throws java.io.IOException

Description copied from interface: Bucket

Write enough data to reconstruct the Bucket, or throw UnsupportedOperationException. Used for recovering in emergencies, should be versioned if necessary.

Specified by:

storeTo in interface Bucket

Overrides:

storeTo in class BaseFileBucket

Throws:

java.io.IOException

hashCode

public int hashCode()

Overrides:

hashCode in class java.lang.Object

equals

public boolean equals(java.lang.Object obj)

Overrides:

equals in class java.lang.Object