Database.Haskey.Store.File

On-disk storage back-end. Can be used as a storage back-end for the append-only page allocator (see Data.BTree.Alloc).

Storage

data Page t where

A decoded page, of a certain type t of kind PageType.

Constructors

EmptyPage :: Page TypeEmpty

ConcurrentMetaPage :: (Key k, Value v) => ConcurrentMeta k v -> Page TypeConcurrentMeta

OverflowPage :: Value v => v -> Page TypeOverflow

LeafNodePage :: (Key k, Value v) => Height Z -> Node Z k v -> Page TypeLeafNode

IndexNodePage :: (Key k, Value v) => Height (S h) -> Node (S h) k v -> Page TypeIndexNode

type Files fp = IORef (Map fp FHandle)

A collection of files, each associated with a certain fp handle.

Each file is a Handle opened in ReadWriteMode and contains a collection of physical pages.

These files can be safely shared between threads.

data FileStoreConfig

File store configuration.

The default configuration can be obtained by using defFileStoreConfig

A configuration with a specific page size can be obtained by using fileStoreConfigWithPageSize.

Constructors

FileStoreConfig

Fields

• fileStoreConfigPageSize :: !PageSize
• fileStoreConfigMaxKeySize :: !Word64
• fileStoreConfigMaxValueSize :: !Word64

Instances

Show FileStoreConfig

Methods

showsPrec :: Int -> FileStoreConfig -> ShowS

show :: FileStoreConfig -> String

showList :: [FileStoreConfig] -> ShowS

Monad m => MonadReader FileStoreConfig (FileStoreT fp m)

Methods

ask :: FileStoreT fp m FileStoreConfig

local :: (FileStoreConfig -> FileStoreConfig) -> FileStoreT fp m a -> FileStoreT fp m a

reader :: (FileStoreConfig -> a) -> FileStoreT fp m a

defFileStoreConfig :: FileStoreConfig

The default configuration

This is an unwrapped fileStoreConfigWithPageSize with a page size of 4096 bytes.

fileStoreConfigWithPageSize :: PageSize -> Maybe FileStoreConfig

Create a configuration with a specific page size.

The maximum key and value sizes are calculated using calculateMaxKeySize and calculateMaxValueSize.

If the page size is too small, Nothing is returned.

data FileStoreT fp m a

Monad in which on-disk storage operations can take place.

Two important instances are StoreM making it a storage back-end, and ConcurrentMetaStoreM making it a storage back-end compatible with the concurrent page allocator.

Instances

Monad m => MonadReader FileStoreConfig (FileStoreT fp m)

Methods

ask :: FileStoreT fp m FileStoreConfig

local :: (FileStoreConfig -> FileStoreConfig) -> FileStoreT fp m a -> FileStoreT fp m a

reader :: (FileStoreConfig -> a) -> FileStoreT fp m a

(Applicative m, Monad m, MonadIO m, MonadThrow m) => StoreM FilePath (FileStoreT FilePath m)

Methods

openHandle :: FilePath -> FileStoreT FilePath m ()

flushHandle :: FilePath -> FileStoreT FilePath m ()

closeHandle :: FilePath -> FileStoreT FilePath m ()

removeHandle :: FilePath -> FileStoreT FilePath m ()

nodePageSize :: (Key key, Value val) => FileStoreT FilePath m (Height height -> Node height key val -> PageSize)

maxPageSize :: FileStoreT FilePath m PageSize

maxKeySize :: FileStoreT FilePath m Word64

maxValueSize :: FileStoreT FilePath m Word64

getNodePage :: (Key key, Value val) => FilePath -> Height height -> Proxy * key -> Proxy * val -> NodeId height key val -> FileStoreT FilePath m (Node height key val)

putNodePage :: (Key key, Value val) => FilePath -> Height height -> NodeId height key val -> Node height key val -> FileStoreT FilePath m ()

getOverflow :: Value val => FilePath -> Proxy * val -> FileStoreT FilePath m val

putOverflow :: Value val => FilePath -> val -> FileStoreT FilePath m ()

listOverflows :: FilePath -> FileStoreT FilePath m [FilePath]

Monad m => Monad (FileStoreT fp m)

Methods

(>>=) :: FileStoreT fp m a -> (a -> FileStoreT fp m b) -> FileStoreT fp m b

(>>) :: FileStoreT fp m a -> FileStoreT fp m b -> FileStoreT fp m b

return :: a -> FileStoreT fp m a

fail :: String -> FileStoreT fp m a

Functor m => Functor (FileStoreT fp m)

Methods

fmap :: (a -> b) -> FileStoreT fp m a -> FileStoreT fp m b

(<$) :: a -> FileStoreT fp m b -> FileStoreT fp m a

Applicative m => Applicative (FileStoreT fp m)

Methods

pure :: a -> FileStoreT fp m a

(<*>) :: FileStoreT fp m (a -> b) -> FileStoreT fp m a -> FileStoreT fp m b

(*>) :: FileStoreT fp m a -> FileStoreT fp m b -> FileStoreT fp m b

(<*) :: FileStoreT fp m a -> FileStoreT fp m b -> FileStoreT fp m a

MonadIO m => MonadIO (FileStoreT fp m)

Methods

liftIO :: IO a -> FileStoreT fp m a

MonadThrow m => MonadThrow (FileStoreT fp m)

Methods

throwM :: Exception e => e -> FileStoreT fp m a

MonadCatch m => MonadCatch (FileStoreT fp m)

Methods

catch :: Exception e => FileStoreT fp m a -> (e -> FileStoreT fp m a) -> FileStoreT fp m a

MonadMask m => MonadMask (FileStoreT fp m)

Methods

mask :: ((forall a. FileStoreT fp m a -> FileStoreT fp m a) -> FileStoreT fp m b) -> FileStoreT fp m b

uninterruptibleMask :: ((forall a. FileStoreT fp m a -> FileStoreT fp m a) -> FileStoreT fp m b) -> FileStoreT fp m b

(Applicative m, Monad m, MonadIO m, MonadCatch m) => ConcurrentMetaStoreM (FileStoreT FilePath m)

Methods

putConcurrentMeta :: (Key k, Value v) => FilePath -> ConcurrentMeta k v -> FileStoreT FilePath m ()

readConcurrentMeta :: (Key k, Value v) => FilePath -> Proxy * k -> Proxy * v -> FileStoreT FilePath m (Maybe (ConcurrentMeta k v))

runFileStoreT

Arguments

:: FileStoreT fp m a

Action

-> FileStoreConfig

Configuration

-> Files fp

Open files

-> m a

Run the storage operations in the FileStoreT monad, given a collection of open files.

newFileStore :: IO (Files fp)

An empty file store, with no open files.

Binary encoding

encodeAndPad :: PageSize -> Page t -> Maybe ByteString

Encode a page padding it to the maxim page size.

Return Nothing of the page is too large to fit into one page size.

Exceptions

newtype FileNotFoundError hnd

Exception thrown when a file is accessed that doesn't exist.

Constructors

FileNotFoundError hnd

Instances

Show hnd => Show (FileNotFoundError hnd)

Methods

showsPrec :: Int -> FileNotFoundError hnd -> ShowS

show :: FileNotFoundError hnd -> String

showList :: [FileNotFoundError hnd] -> ShowS

(Typeable * hnd, Show hnd) => Exception (FileNotFoundError hnd)

Methods

toException :: FileNotFoundError hnd -> SomeException

fromException :: SomeException -> Maybe (FileNotFoundError hnd)

displayException :: FileNotFoundError hnd -> String

data PageOverflowError

Exception thrown when a page that is too large is written.

As used in putNodePage.

Constructors

PageOverflowError

Instances

Show PageOverflowError

Methods

showsPrec :: Int -> PageOverflowError -> ShowS

show :: PageOverflowError -> String

showList :: [PageOverflowError] -> ShowS

Exception PageOverflowError

Methods

toException :: PageOverflowError -> SomeException

fromException :: SomeException -> Maybe PageOverflowError

displayException :: PageOverflowError -> String

data WrongNodeTypeError

Exception thrown when a node cannot be cast to the right type.

As used in getNodePage.

Constructors

WrongNodeTypeError

Instances

Show WrongNodeTypeError

Methods

showsPrec :: Int -> WrongNodeTypeError -> ShowS

show :: WrongNodeTypeError -> String

showList :: [WrongNodeTypeError] -> ShowS

Exception WrongNodeTypeError

Methods

toException :: WrongNodeTypeError -> SomeException

fromException :: SomeException -> Maybe WrongNodeTypeError

displayException :: WrongNodeTypeError -> String

data WrongOverflowValueError

Exception thrown when a value from an overflow page cannot be cast.

As used in getOverflow.

Constructors

WrongOverflowValueError

Instances

Show WrongOverflowValueError

Methods

showsPrec :: Int -> WrongOverflowValueError -> ShowS

show :: WrongOverflowValueError -> String

showList :: [WrongOverflowValueError] -> ShowS

Exception WrongOverflowValueError

Methods

toException :: WrongOverflowValueError -> SomeException

fromException :: SomeException -> Maybe WrongOverflowValueError

displayException :: WrongOverflowValueError -> String