Safe Haskell	None
Language	Haskell2010

FoundationDB.Layer.Directory

Contents

Advanced usage

Description

The directory layer provides tools for creating a hierarchy of Subspaces, which can be operated on efficiently with a directory-like API. This is one of the official layers supported by all language bindings. See the official FoundationDB documentation for more information.

This implementation of the directory layer does not yet support directory partitions. They will be added in the future.

Synopsis

data DirectoryLayer
defaultDirLayer :: DirectoryLayer
newDirectoryLayer :: Subspace -> Subspace -> Bool -> DirectoryLayer
data Directory
type Path = [Text]
dirSubspace :: Directory -> Subspace
dirPath :: Directory -> Path
dirLayer :: Directory -> ByteString
open :: DirectoryLayer -> Path -> Transaction (Maybe Directory)
createOrOpen :: DirectoryLayer -> Path -> Transaction Directory
move :: DirectoryLayer -> Path -> Path -> Transaction (Maybe MoveError)
remove :: DirectoryLayer -> Path -> Transaction Bool
exists :: DirectoryLayer -> Path -> Transaction Bool
list :: DirectoryLayer -> Path -> Transaction (Seq Text)
open' :: DirectoryLayer -> Path -> ByteString -> Maybe ByteString -> Transaction (Maybe Directory)
createOrOpen' :: DirectoryLayer -> Path -> ByteString -> Maybe ByteString -> Transaction Directory

Documentation

data DirectoryLayer Source #

Represents a directory tree. A value of this type must be supplied to all functions in this module.

Instances

Instances details

Eq DirectoryLayer Source #
Instance details Defined in FoundationDB.Layer.Directory.Internal Methods (==) :: DirectoryLayer -> DirectoryLayer -> Bool # (/=) :: DirectoryLayer -> DirectoryLayer -> Bool #
Ord DirectoryLayer Source #
Instance details Defined in FoundationDB.Layer.Directory.Internal Methods compare :: DirectoryLayer -> DirectoryLayer -> Ordering # (<) :: DirectoryLayer -> DirectoryLayer -> Bool # (<=) :: DirectoryLayer -> DirectoryLayer -> Bool # (>) :: DirectoryLayer -> DirectoryLayer -> Bool # (>=) :: DirectoryLayer -> DirectoryLayer -> Bool # max :: DirectoryLayer -> DirectoryLayer -> DirectoryLayer # min :: DirectoryLayer -> DirectoryLayer -> DirectoryLayer #
Show DirectoryLayer Source #
Instance details Defined in FoundationDB.Layer.Directory.Internal Methods showsPrec :: Int -> DirectoryLayer -> ShowS # show :: DirectoryLayer -> String # showList :: [DirectoryLayer] -> ShowS #

defaultDirLayer :: DirectoryLayer Source #

The default directory layer has node subspace prefix 0xfe. This corresponds to using the defaults for all arguments to the DirectoryLayer constructor in other languages' bindings.

newDirectoryLayer Source #

Arguments

:: Subspace	node subspace for directory metadata
-> Subspace	content subspace
-> Bool	allow manual prefixes
-> DirectoryLayer

Creates a new directory layer, containing a hierarchy of directories.

data Directory Source #

Represents a single directory.

Instances

Instances details

Eq Directory Source #
Instance details Defined in FoundationDB.Layer.Directory.Internal Methods (==) :: Directory -> Directory -> Bool # (/=) :: Directory -> Directory -> Bool #
Ord Directory Source #
Instance details Defined in FoundationDB.Layer.Directory.Internal Methods compare :: Directory -> Directory -> Ordering # (<) :: Directory -> Directory -> Bool # (<=) :: Directory -> Directory -> Bool # (>) :: Directory -> Directory -> Bool # (>=) :: Directory -> Directory -> Bool # max :: Directory -> Directory -> Directory # min :: Directory -> Directory -> Directory #
Show Directory Source #
Instance details Defined in FoundationDB.Layer.Directory.Internal Methods showsPrec :: Int -> Directory -> ShowS # show :: Directory -> String # showList :: [Directory] -> ShowS #

type Path = [Text] Source #

A path is a list of unicode strings.

dirSubspace :: Directory -> Subspace Source #

Gets the content subspace of a directory, which can be used to store tuple-based keys.

dirPath :: Directory -> Path Source #

Gets the path of a directory.

dirLayer :: Directory -> ByteString Source #

Gets the layer tag that was specified when the directory was created.

open :: DirectoryLayer -> Path -> Transaction (Maybe Directory) Source #

Tries to open a directory at the given path. If the directory exists, returns it. Otherwise, returns Nothing.

createOrOpen :: DirectoryLayer -> Path -> Transaction Directory Source #

Opens a directory at the given path. If the directory does not exist, it is created.

move Source #

Arguments

:: DirectoryLayer
-> Path	from path
-> Path	to path
-> Transaction (Maybe MoveError)

Move a directory from one path to another. Returns Just err if an error occurred. If an error is returned, the directory structure is left unchanged.

remove :: DirectoryLayer -> Path -> Transaction Bool Source #

Remove a directory path, its contents, and all subdirectories. Returns True if removal succeeds. Fails for nonexistent paths and the root directory. In cases of failure, the directory structure is unchanged.

exists :: DirectoryLayer -> Path -> Transaction Bool Source #

Returns True iff the given path exists.

list :: DirectoryLayer -> Path -> Transaction (Seq Text) Source #

List the names of the immediate subdirectories of a directory. Returns an empty list if the directory does not exist.

Advanced usage

open' Source #

Arguments

:: DirectoryLayer
-> Path
-> ByteString	layer
-> Maybe ByteString	optional custom prefix
-> Transaction (Maybe Directory)

Open a directory, with optional custom prefix and layer. Returns Nothing if the directory doesn't exist.

createOrOpen' Source #

Arguments

:: DirectoryLayer
-> Path
-> ByteString	layer
-> Maybe ByteString	optional custom prefix
-> Transaction Directory

Opens a directory at the given path, with optional custom prefix and layer.