Safe Haskell | None |
---|---|
Language | Haskell2010 |
On-disk storage back-end. Can be used as a storage back-end for the append-only page allocator (see Data.BTree.Alloc).
- data Page t where
- 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)
- data FileStoreConfig = FileStoreConfig {}
- defFileStoreConfig :: FileStoreConfig
- fileStoreConfigWithPageSize :: PageSize -> Maybe FileStoreConfig
- data FileStoreT fp m a
- runFileStoreT :: FileStoreT fp m a -> FileStoreConfig -> Files fp -> m a
- newFileStore :: IO (Files fp)
- encodeAndPad :: PageSize -> Page t -> Maybe ByteString
- newtype FileNotFoundError hnd = FileNotFoundError hnd
- data PageOverflowError = PageOverflowError
- data WrongNodeTypeError = WrongNodeTypeError
- data WrongOverflowValueError = WrongOverflowValueError
Storage
A decoded page, of a certain type t
of kind PageType
.
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) Source #
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 Source #
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
.
Show FileStoreConfig Source # | |
Monad m => MonadReader FileStoreConfig (FileStoreT fp m) Source # | |
defFileStoreConfig :: FileStoreConfig Source #
The default configuration
This is an unwrapped fileStoreConfigWithPageSize
with a page size of 4096
bytes.
fileStoreConfigWithPageSize :: PageSize -> Maybe FileStoreConfig Source #
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 Source #
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.
Monad m => MonadReader FileStoreConfig (FileStoreT fp m) Source # | |
(Applicative m, Monad m, MonadIO m, MonadThrow m) => StoreM FilePath (FileStoreT FilePath m) Source # | |
Monad m => Monad (FileStoreT fp m) Source # | |
Functor m => Functor (FileStoreT fp m) Source # | |
Applicative m => Applicative (FileStoreT fp m) Source # | |
MonadIO m => MonadIO (FileStoreT fp m) Source # | |
MonadThrow m => MonadThrow (FileStoreT fp m) Source # | |
MonadCatch m => MonadCatch (FileStoreT fp m) Source # | |
MonadMask m => MonadMask (FileStoreT fp m) Source # | |
(Applicative m, Monad m, MonadIO m, MonadCatch m) => ConcurrentMetaStoreM (FileStoreT FilePath m) Source # | |
:: 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) Source #
An empty file store, with no open files.
Binary encoding
encodeAndPad :: PageSize -> Page t -> Maybe ByteString Source #
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 Source #
Exception thrown when a file is accessed that doesn't exist.
data PageOverflowError Source #
Exception thrown when a page that is too large is written.
As used in putNodePage
.
data WrongNodeTypeError Source #
Exception thrown when a node cannot be cast to the right type.
As used in getNodePage
.
data WrongOverflowValueError Source #
Exception thrown when a value from an overflow page cannot be cast.
As used in getOverflow
.