Package convex.dlfs

Class DLFSNode

java.lang.Object

convex.dlfs.DLFSNode

public class DLFSNode
extends Object

Static utility class for working with DLFS Node structures

Field Summary

Fields

Modifier and Type	Field	Description
static final long	NODE_LENGTH
static final int	POS_DATA
static final int	POS_DIR
static final int	POS_METADATA
static final int	POS_UTIME

Constructor Summary

Constructors

Constructor	Description
DLFSNode()

Method Summary

Modifier and Type	Method	Description
static AVector<ACell>	createDirectory(CVMLong timestamp)
static AVector<ACell>	createEmptyFile(CVMLong timestamp)
static AVector<ACell>	createTombstone(CVMLong timestamp)
static ABlob	getData(AVector<ACell> node)	Gets the data from a DLFS file node, or nil if not a regular File
static AHashMap<AString,AVector<ACell>>	getDirectoryEntries(AVector<ACell> dirNode)	Gets the directory entries for a node
static MapEntry<AString,AVector<ACell>>	getDirectoryEntry(AVector<ACell> node, AString name)
static Blob	getMetaData(AVector<ACell> node)	Gets the metadata from a DLFS node
static CVMLong	getUTime(AVector<ACell> node)	Gets the metadata from a DLFS node
static boolean	isDirectory(AVector<ACell> node)
static boolean	isRegularFile(AVector<ACell> node)
static boolean	isTombstone(AVector<ACell> node)	Returns true iff the node is a DLFS tombstone
static AVector<ACell>	merge(AVector<ACell> a, AVector<ACell> b, CVMLong time)	Merges two DLFS nodes recursively.
static AVector<ACell>	navigate(AVector<ACell> node, DLPath path)	Navigate down a path relative to a DLFS Node.
static AVector<ACell>	updateNode(AVector<ACell> rootNode, DLPath path, AVector<ACell> newNode, CVMLong utime)	Update a node at a path relative to a root node

Methods inherited from class java.lang.Object

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

Field Details

NODE_LENGTH

public static final long NODE_LENGTH

See Also:

• Constant Field Values

POS_DIR

public static final int POS_DIR

See Also:

• Constant Field Values

POS_DATA

public static final int POS_DATA

See Also:

• Constant Field Values

POS_METADATA

public static final int POS_METADATA

See Also:

• Constant Field Values

POS_UTIME

public static final int POS_UTIME

See Also:

• Constant Field Values

Constructor Details

DLFSNode

public DLFSNode()

Method Details

isDirectory

public static boolean isDirectory(AVector<ACell> node)

isRegularFile

public static boolean isRegularFile(AVector<ACell> node)

navigate

public static AVector<ACell> navigate(AVector<ACell> node,
 DLPath path)

Navigate down a path relative to a DLFS Node.

Parameters:

node - Node from which to navigate

path - Path to navigate from (assumed to be relative)

Returns:

Found node, or null if doesn't exist

getDirectoryEntries

public static AHashMap<AString,AVector<ACell>> getDirectoryEntries(AVector<ACell> dirNode)

Gets the directory entries for a node

Parameters:

dirNode - Node which is assumed to be a directory

Returns:

Map of directory entries, or null if not a directory

updateNode

public static AVector<ACell> updateNode(AVector<ACell> rootNode,
 DLPath path,
 AVector<ACell> newNode,
 CVMLong utime)

Update a node at a path relative to a root node

Parameters:

rootNode - Root node of file system

path - Path relative to root

newNode - New node, or null to delete a node

utime - Timestamp to set on any directories changed

Returns:

Updated root node, or null if update failed (parent(s) not a directory)

getData

public static ABlob getData(AVector<ACell> node)

Gets the data from a DLFS file node, or nil if not a regular File

getMetaData

public static Blob getMetaData(AVector<ACell> node)

Gets the metadata from a DLFS node

getUTime

public static CVMLong getUTime(AVector<ACell> node)

Gets the metadata from a DLFS node

getDirectoryEntry

public static MapEntry<AString,AVector<ACell>> getDirectoryEntry(AVector<ACell> node,
 AString name)

Parameters:

node - Node to check for directory

name - Directory entry name

Returns:

Directory entry, return null if not found or node is not a directory

isTombstone

public static boolean isTombstone(AVector<ACell> node)

Returns true iff the node is a DLFS tombstone

Parameters:

node - Node to test

Returns:

True if a tombstone, false if anything else (including null)

createTombstone

public static AVector<ACell> createTombstone(CVMLong timestamp)

createDirectory

public static AVector<ACell> createDirectory(CVMLong timestamp)

createEmptyFile

public static AVector<ACell> createEmptyFile(CVMLong timestamp)

merge

public static AVector<ACell> merge(AVector<ACell> a,
 AVector<ACell> b,
 CVMLong time)

Merges two DLFS nodes recursively. Favours newer (utime) entries in case of conflicts.

Parameters:

a - First node (non-null). Favoured in result if all else equal.

b - Second node (non-null)

time - Update time for merged changes

Returns:

Merged node