MissingH- Large utility library

CopyrightCopyright (C) 2004-2011 John Goerzen
MaintainerJohn Goerzen <jgoerzen@complete.org>
Safe HaskellSafe




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

Copyright (c) 2004-2005 John Goerzen, jgoerzen@complete.org

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 Source #

The main HVFS class.

Default implementations of these functions are provided:

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



vGetCurrentDirectory :: a -> IO FilePath Source #

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

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

vDoesFileExist :: a -> FilePath -> IO Bool Source #

vDoesDirectoryExist :: a -> FilePath -> IO Bool Source #

vDoesExist :: a -> FilePath -> IO Bool Source #

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 () Source #

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

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

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

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

vGetFileStatus :: a -> FilePath -> IO HVFSStatEncap Source #

vGetSymbolicLinkStatus :: a -> FilePath -> IO HVFSStatEncap Source #

vGetModificationTime :: a -> FilePath -> IO ClockTime Source #

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

Raise an error relating to actions on this class.

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

vReadSymbolicLink :: a -> FilePath -> IO FilePath Source #

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


HVFS SystemFS Source # 
HVFS MemoryVFS Source # 
HVFS a => HVFS (HVFSChroot a) Source # 
HVFS a => HVFS (HVFSReadOnly a) Source # 

class Show a => HVFSStat a where Source #

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


HVFSStat FileStatus Source # 
HVFSStat SimpleStat Source # 

class HVFS a => HVFSOpenable a where Source #

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

Minimal complete definition


data HVFSOpenEncap Source #

Similar to HVFSStatEncap, but for vOpen result.


HVIO a => HVFSOpenEncap a 

data HVFSStatEncap Source #

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


HVFSStat a => HVFSStatEncap a 

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

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 Source #

Similar to withStat, but for the vOpen result.

data SystemFS Source #




Eq SystemFS Source # 
Show SystemFS Source # 
HVFSOpenable SystemFS Source # 
HVFS SystemFS Source # 

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 UserID = CUid #

type GroupID = CGid #

Orphan instances