System.IO.HVFS

Haskell Virtual FS -- generic support for real or virtual filesystem in Haskell

Copyright (c) 2004-2005 John Goerzen, [e-mail]

The idea of this module is to provide virtualization of filesystem calls. In addition to the "real" system filesystem, you can also provide access to other, virtual, filesystems using the same set of calls. Examples of such virtual filesystems might include a remote FTP server, WebDAV server, a local Hashtable, a ConfigParser object, or any other data structure you can represent as a tree of named nodes containing strings.

Each HVFS function takes a HVFS "handle" (HVFS instance) as its first parameter. If you wish to operate on the standard system filesystem, you can just use SystemFS.

The MissingH.HVFS.IO.InstanceHelpers module contains some code to help you make your own HVFS instances.

The HVFSOpenable class works together with the System.IO.HVIO module to provide a complete virtual filesystem and I/O model that allows you to open up virtual filesystem files and act upon them in a manner similar to standard Handles.

Implementation Classes / Types

class Show a => HVFS a where

The main HVFS class.

Default implementations of these functions are provided:

• vGetModificationTime -- implemented in terms of vGetFileStatus
• vRaiseError
• vDoesFileExist -- implemented in terms of vGetFileStatus
• vDoesDirectoryExist -- implemented in terms of vGetFileStatus
• vDoesExist -- implemented in terms of vGetSymbolicLinkStatus
• vGetSymbolicLinkStatus -- set to call vGetFileStatus.

Default implementations of all other functions will generate an isIllegalOperation error, since they are assumed to be un-implemented.

You should always provide at least a vGetFileStatus call, and almost certainly several of the others.

Most of these functions correspond to functions in System.Directory or System.Posix.Files. Please see detailed documentation on them there.

Minimal complete definition

vGetFileStatus

Methods

vGetCurrentDirectory :: a -> IO FilePath

vSetCurrentDirectory :: a -> FilePath -> IO ()

vGetDirectoryContents :: a -> FilePath -> IO [FilePath]

vDoesFileExist :: a -> FilePath -> IO Bool

vDoesDirectoryExist :: a -> FilePath -> IO Bool

vDoesExist :: a -> FilePath -> IO Bool

True if the file exists, regardless of what type it is. This is even True if the given path is a broken symlink.

vCreateDirectory :: a -> FilePath -> IO ()

vRemoveDirectory :: a -> FilePath -> IO ()

vRenameDirectory :: a -> FilePath -> FilePath -> IO ()

vRemoveFile :: a -> FilePath -> IO ()

vRenameFile :: a -> FilePath -> FilePath -> IO ()

vGetFileStatus :: a -> FilePath -> IO HVFSStatEncap

vGetSymbolicLinkStatus :: a -> FilePath -> IO HVFSStatEncap

vGetModificationTime :: a -> FilePath -> IO ClockTime

vRaiseError :: a -> IOErrorType -> String -> Maybe FilePath -> IO c

Raise an error relating to actions on this class.

vCreateSymbolicLink :: a -> FilePath -> FilePath -> IO ()

vReadSymbolicLink :: a -> FilePath -> IO FilePath

vCreateLink :: a -> FilePath -> FilePath -> IO ()

Instances

HVFS SystemFS

Defined in System.IO.HVFS

Methods

vGetCurrentDirectory :: SystemFS -> IO FilePath

vSetCurrentDirectory :: SystemFS -> FilePath -> IO ()

vGetDirectoryContents :: SystemFS -> FilePath -> IO [FilePath]

vDoesFileExist :: SystemFS -> FilePath -> IO Bool

vDoesDirectoryExist :: SystemFS -> FilePath -> IO Bool

vDoesExist :: SystemFS -> FilePath -> IO Bool

vCreateDirectory :: SystemFS -> FilePath -> IO ()

vRemoveDirectory :: SystemFS -> FilePath -> IO ()

vRenameDirectory :: SystemFS -> FilePath -> FilePath -> IO ()

vRemoveFile :: SystemFS -> FilePath -> IO ()

vRenameFile :: SystemFS -> FilePath -> FilePath -> IO ()

vGetFileStatus :: SystemFS -> FilePath -> IO HVFSStatEncap

vGetSymbolicLinkStatus :: SystemFS -> FilePath -> IO HVFSStatEncap

vGetModificationTime :: SystemFS -> FilePath -> IO ClockTime

vRaiseError :: SystemFS -> IOErrorType -> String -> Maybe FilePath -> IO c

vCreateSymbolicLink :: SystemFS -> FilePath -> FilePath -> IO ()

vReadSymbolicLink :: SystemFS -> FilePath -> IO FilePath

vCreateLink :: SystemFS -> FilePath -> FilePath -> IO ()

HVFS MemoryVFS

Defined in System.IO.HVFS.InstanceHelpers

Methods

vGetCurrentDirectory :: MemoryVFS -> IO FilePath

vSetCurrentDirectory :: MemoryVFS -> FilePath -> IO ()

vGetDirectoryContents :: MemoryVFS -> FilePath -> IO [FilePath]

vDoesFileExist :: MemoryVFS -> FilePath -> IO Bool

vDoesDirectoryExist :: MemoryVFS -> FilePath -> IO Bool

vDoesExist :: MemoryVFS -> FilePath -> IO Bool

vCreateDirectory :: MemoryVFS -> FilePath -> IO ()

vRemoveDirectory :: MemoryVFS -> FilePath -> IO ()

vRenameDirectory :: MemoryVFS -> FilePath -> FilePath -> IO ()

vRemoveFile :: MemoryVFS -> FilePath -> IO ()

vRenameFile :: MemoryVFS -> FilePath -> FilePath -> IO ()

vGetFileStatus :: MemoryVFS -> FilePath -> IO HVFSStatEncap

vGetSymbolicLinkStatus :: MemoryVFS -> FilePath -> IO HVFSStatEncap

vGetModificationTime :: MemoryVFS -> FilePath -> IO ClockTime

vRaiseError :: MemoryVFS -> IOErrorType -> String -> Maybe FilePath -> IO c

vCreateSymbolicLink :: MemoryVFS -> FilePath -> FilePath -> IO ()

vReadSymbolicLink :: MemoryVFS -> FilePath -> IO FilePath

vCreateLink :: MemoryVFS -> FilePath -> FilePath -> IO ()

HVFS a => HVFS (HVFSChroot a)

Defined in System.IO.HVFS.Combinators

Methods

vGetCurrentDirectory :: HVFSChroot a -> IO FilePath

vSetCurrentDirectory :: HVFSChroot a -> FilePath -> IO ()

vGetDirectoryContents :: HVFSChroot a -> FilePath -> IO [FilePath]

vDoesFileExist :: HVFSChroot a -> FilePath -> IO Bool

vDoesDirectoryExist :: HVFSChroot a -> FilePath -> IO Bool

vDoesExist :: HVFSChroot a -> FilePath -> IO Bool

vCreateDirectory :: HVFSChroot a -> FilePath -> IO ()

vRemoveDirectory :: HVFSChroot a -> FilePath -> IO ()

vRenameDirectory :: HVFSChroot a -> FilePath -> FilePath -> IO ()

vRemoveFile :: HVFSChroot a -> FilePath -> IO ()

vRenameFile :: HVFSChroot a -> FilePath -> FilePath -> IO ()

vGetFileStatus :: HVFSChroot a -> FilePath -> IO HVFSStatEncap

vGetSymbolicLinkStatus :: HVFSChroot a -> FilePath -> IO HVFSStatEncap

vGetModificationTime :: HVFSChroot a -> FilePath -> IO ClockTime

vRaiseError :: HVFSChroot a -> IOErrorType -> String -> Maybe FilePath -> IO c

vCreateSymbolicLink :: HVFSChroot a -> FilePath -> FilePath -> IO ()

vReadSymbolicLink :: HVFSChroot a -> FilePath -> IO FilePath

vCreateLink :: HVFSChroot a -> FilePath -> FilePath -> IO ()

HVFS a => HVFS (HVFSReadOnly a)

Defined in System.IO.HVFS.Combinators

Methods

vGetCurrentDirectory :: HVFSReadOnly a -> IO FilePath

vSetCurrentDirectory :: HVFSReadOnly a -> FilePath -> IO ()

vGetDirectoryContents :: HVFSReadOnly a -> FilePath -> IO [FilePath]

vDoesFileExist :: HVFSReadOnly a -> FilePath -> IO Bool

vDoesDirectoryExist :: HVFSReadOnly a -> FilePath -> IO Bool

vDoesExist :: HVFSReadOnly a -> FilePath -> IO Bool

vCreateDirectory :: HVFSReadOnly a -> FilePath -> IO ()

vRemoveDirectory :: HVFSReadOnly a -> FilePath -> IO ()

vRenameDirectory :: HVFSReadOnly a -> FilePath -> FilePath -> IO ()

vRemoveFile :: HVFSReadOnly a -> FilePath -> IO ()

vRenameFile :: HVFSReadOnly a -> FilePath -> FilePath -> IO ()

vGetFileStatus :: HVFSReadOnly a -> FilePath -> IO HVFSStatEncap

vGetSymbolicLinkStatus :: HVFSReadOnly a -> FilePath -> IO HVFSStatEncap

vGetModificationTime :: HVFSReadOnly a -> FilePath -> IO ClockTime

vRaiseError :: HVFSReadOnly a -> IOErrorType -> String -> Maybe FilePath -> IO c

vCreateSymbolicLink :: HVFSReadOnly a -> FilePath -> FilePath -> IO ()

vReadSymbolicLink :: HVFSReadOnly a -> FilePath -> IO FilePath

vCreateLink :: HVFSReadOnly a -> FilePath -> FilePath -> IO ()

class Show a => HVFSStat a where

Evaluating types of files and information about them.

This corresponds to the System.Posix.Types.FileStatus type, and indeed, that is one instance of this class.

Inplementators must, at minimum, implement vIsDirectory and vIsRegularFile.

Default implementations of everything else are provided, returning reasonable values.

A default implementation of this is not currently present on Windows.

Minimal complete definition

vIsRegularFile, vIsDirectory

Methods

vDeviceID :: a -> DeviceID

vFileID :: a -> FileID

vFileMode :: a -> FileMode

Refers to file permissions, NOT the st_mode field from stat(2)

vLinkCount :: a -> LinkCount

vFileOwner :: a -> UserID

vFileGroup :: a -> GroupID

vSpecialDeviceID :: a -> DeviceID

vFileSize :: a -> FileOffset

vAccessTime :: a -> EpochTime

vModificationTime :: a -> EpochTime

vStatusChangeTime :: a -> EpochTime

vIsBlockDevice :: a -> Bool

vIsCharacterDevice :: a -> Bool

vIsNamedPipe :: a -> Bool

vIsRegularFile :: a -> Bool

vIsDirectory :: a -> Bool

vIsSymbolicLink :: a -> Bool

vIsSocket :: a -> Bool

Instances

HVFSStat FileStatus

Defined in System.IO.HVFS

Methods

vDeviceID :: FileStatus -> DeviceID

vFileID :: FileStatus -> FileID

vFileMode :: FileStatus -> FileMode

vLinkCount :: FileStatus -> LinkCount

vFileOwner :: FileStatus -> UserID

vFileGroup :: FileStatus -> GroupID

vSpecialDeviceID :: FileStatus -> DeviceID

vFileSize :: FileStatus -> FileOffset

vAccessTime :: FileStatus -> EpochTime

vModificationTime :: FileStatus -> EpochTime

vStatusChangeTime :: FileStatus -> EpochTime

vIsBlockDevice :: FileStatus -> Bool

vIsCharacterDevice :: FileStatus -> Bool

vIsNamedPipe :: FileStatus -> Bool

vIsRegularFile :: FileStatus -> Bool

vIsDirectory :: FileStatus -> Bool

vIsSymbolicLink :: FileStatus -> Bool

vIsSocket :: FileStatus -> Bool

HVFSStat SimpleStat

Defined in System.IO.HVFS.InstanceHelpers

Methods

vDeviceID :: SimpleStat -> DeviceID

vFileID :: SimpleStat -> FileID

vFileMode :: SimpleStat -> FileMode

vLinkCount :: SimpleStat -> LinkCount

vFileOwner :: SimpleStat -> UserID

vFileGroup :: SimpleStat -> GroupID

vSpecialDeviceID :: SimpleStat -> DeviceID

vFileSize :: SimpleStat -> FileOffset

vAccessTime :: SimpleStat -> EpochTime

vModificationTime :: SimpleStat -> EpochTime

vStatusChangeTime :: SimpleStat -> EpochTime

vIsBlockDevice :: SimpleStat -> Bool

vIsCharacterDevice :: SimpleStat -> Bool

vIsNamedPipe :: SimpleStat -> Bool

vIsRegularFile :: SimpleStat -> Bool

vIsDirectory :: SimpleStat -> Bool

vIsSymbolicLink :: SimpleStat -> Bool

vIsSocket :: SimpleStat -> Bool

class HVFS a => HVFSOpenable a where

Types that can open a HVIO object should be instances of this class. You need only implement vOpen.

Minimal complete definition

vOpen

Methods

vOpen :: a -> FilePath -> IOMode -> IO HVFSOpenEncap

vReadFile :: a -> FilePath -> IO String

vWriteFile :: a -> FilePath -> String -> IO ()

vOpenBinaryFile :: a -> FilePath -> IOMode -> IO HVFSOpenEncap

Instances

HVFSOpenable SystemFS

Defined in System.IO.HVFS

Methods

vOpen :: SystemFS -> FilePath -> IOMode -> IO HVFSOpenEncap

vReadFile :: SystemFS -> FilePath -> IO String

vWriteFile :: SystemFS -> FilePath -> String -> IO ()

vOpenBinaryFile :: SystemFS -> FilePath -> IOMode -> IO HVFSOpenEncap

HVFSOpenable MemoryVFS

Defined in System.IO.HVFS.InstanceHelpers

Methods

vOpen :: MemoryVFS -> FilePath -> IOMode -> IO HVFSOpenEncap

vReadFile :: MemoryVFS -> FilePath -> IO String

vWriteFile :: MemoryVFS -> FilePath -> String -> IO ()

vOpenBinaryFile :: MemoryVFS -> FilePath -> IOMode -> IO HVFSOpenEncap

HVFSOpenable a => HVFSOpenable (HVFSChroot a)

Defined in System.IO.HVFS.Combinators

Methods

vOpen :: HVFSChroot a -> FilePath -> IOMode -> IO HVFSOpenEncap

vReadFile :: HVFSChroot a -> FilePath -> IO String

vWriteFile :: HVFSChroot a -> FilePath -> String -> IO ()

vOpenBinaryFile :: HVFSChroot a -> FilePath -> IOMode -> IO HVFSOpenEncap

HVFSOpenable a => HVFSOpenable (HVFSReadOnly a)

Defined in System.IO.HVFS.Combinators

Methods

vOpen :: HVFSReadOnly a -> FilePath -> IOMode -> IO HVFSOpenEncap

vReadFile :: HVFSReadOnly a -> FilePath -> IO String

vWriteFile :: HVFSReadOnly a -> FilePath -> String -> IO ()

vOpenBinaryFile :: HVFSReadOnly a -> FilePath -> IOMode -> IO HVFSOpenEncap

data HVFSOpenEncap

Similar to HVFSStatEncap, but for vOpen result.

Constructors

HVIO a => HVFSOpenEncap a

data HVFSStatEncap

Encapsulate a HVFSStat result. This is required due to Haskell typing restrictions. You can get at it with:

case encap of
   HVFSStatEncap x -> -- now use x

Constructors

HVFSStat a => HVFSStatEncap a

withStat :: forall b. HVFSStatEncap -> (forall a. HVFSStat a => a -> b) -> b

Convenience function for working with stat -- takes a stat result and a function that uses it, and returns the result.

Here is an example from the HVFS source:

   vGetModificationTime fs fp =
      do s <- vGetFileStatus fs fp
         return $ epochToClockTime (withStat s vModificationTime)

See epochToClockTime for more information.

withOpen :: forall b. HVFSOpenEncap -> (forall a. HVIO a => a -> b) -> b

Similar to withStat, but for the vOpen result.

data SystemFS

Constructors

SystemFS

Instances

Eq SystemFS

Defined in System.IO.HVFS

Methods

(==) :: SystemFS -> SystemFS -> Bool

(/=) :: SystemFS -> SystemFS -> Bool

Show SystemFS

Defined in System.IO.HVFS

Methods

showsPrec :: Int -> SystemFS -> ShowS

show :: SystemFS -> String

showList :: [SystemFS] -> ShowS

HVFSOpenable SystemFS

Defined in System.IO.HVFS

Methods

vOpen :: SystemFS -> FilePath -> IOMode -> IO HVFSOpenEncap

vReadFile :: SystemFS -> FilePath -> IO String

vWriteFile :: SystemFS -> FilePath -> String -> IO ()

vOpenBinaryFile :: SystemFS -> FilePath -> IOMode -> IO HVFSOpenEncap

HVFS SystemFS

Defined in System.IO.HVFS

Methods

vGetCurrentDirectory :: SystemFS -> IO FilePath

vSetCurrentDirectory :: SystemFS -> FilePath -> IO ()

vGetDirectoryContents :: SystemFS -> FilePath -> IO [FilePath]

vDoesFileExist :: SystemFS -> FilePath -> IO Bool

vDoesDirectoryExist :: SystemFS -> FilePath -> IO Bool

vDoesExist :: SystemFS -> FilePath -> IO Bool

vCreateDirectory :: SystemFS -> FilePath -> IO ()

vRemoveDirectory :: SystemFS -> FilePath -> IO ()

vRenameDirectory :: SystemFS -> FilePath -> FilePath -> IO ()

vRemoveFile :: SystemFS -> FilePath -> IO ()

vRenameFile :: SystemFS -> FilePath -> FilePath -> IO ()

vGetFileStatus :: SystemFS -> FilePath -> IO HVFSStatEncap

vGetSymbolicLinkStatus :: SystemFS -> FilePath -> IO HVFSStatEncap

vGetModificationTime :: SystemFS -> FilePath -> IO ClockTime

vRaiseError :: SystemFS -> IOErrorType -> String -> Maybe FilePath -> IO c

vCreateSymbolicLink :: SystemFS -> FilePath -> FilePath -> IO ()

vReadSymbolicLink :: SystemFS -> FilePath -> IO FilePath

vCreateLink :: SystemFS -> FilePath -> FilePath -> IO ()

Re-exported types from other modules

type FilePath = String

File and directory names are values of type String, whose precise meaning is operating system dependent. Files can be opened, yielding a handle which can then be used to operate on the contents of that file.

type DeviceID = CDev

type FileID = CIno

type FileMode = CMode

type LinkCount = CNlink

type UserID = CUid

type GroupID = CGid

type FileOffset = COff

type EpochTime = CTime

data IOMode

See openFile

Instances

Enum IOMode

Since: base-4.2.0.0

Defined in GHC.IO.IOMode

Methods

succ :: IOMode -> IOMode

pred :: IOMode -> IOMode

toEnum :: Int -> IOMode

fromEnum :: IOMode -> Int

enumFrom :: IOMode -> [IOMode]

enumFromThen :: IOMode -> IOMode -> [IOMode]

enumFromTo :: IOMode -> IOMode -> [IOMode]

enumFromThenTo :: IOMode -> IOMode -> IOMode -> [IOMode]

Eq IOMode

Since: base-4.2.0.0

Defined in GHC.IO.IOMode

Methods

(==) :: IOMode -> IOMode -> Bool

(/=) :: IOMode -> IOMode -> Bool

Ord IOMode

Since: base-4.2.0.0

Defined in GHC.IO.IOMode

Methods

compare :: IOMode -> IOMode -> Ordering

(<) :: IOMode -> IOMode -> Bool

(<=) :: IOMode -> IOMode -> Bool

(>) :: IOMode -> IOMode -> Bool

(>=) :: IOMode -> IOMode -> Bool

max :: IOMode -> IOMode -> IOMode

min :: IOMode -> IOMode -> IOMode

Read IOMode

Since: base-4.2.0.0

Defined in GHC.IO.IOMode

Methods

readsPrec :: Int -> ReadS IOMode

readList :: ReadS [IOMode]

readPrec :: ReadPrec IOMode

readListPrec :: ReadPrec [IOMode]

Show IOMode

Since: base-4.2.0.0

Defined in GHC.IO.IOMode

Methods

showsPrec :: Int -> IOMode -> ShowS

show :: IOMode -> String

showList :: [IOMode] -> ShowS

Ix IOMode

Since: base-4.2.0.0

Defined in GHC.IO.IOMode

Methods

range :: (IOMode, IOMode) -> [IOMode]

index :: (IOMode, IOMode) -> IOMode -> Int

unsafeIndex :: (IOMode, IOMode) -> IOMode -> Int

inRange :: (IOMode, IOMode) -> IOMode -> Bool

rangeSize :: (IOMode, IOMode) -> Int

unsafeRangeSize :: (IOMode, IOMode) -> Int

Orphan instances

Show FileStatus

Methods

showsPrec :: Int -> FileStatus -> ShowS

show :: FileStatus -> String

showList :: [FileStatus] -> ShowS