|Maintainer||John Goerzen <email@example.com> |
Haskell Virtual FS -- generic support for real or virtual filesystem in Haskell
Copyright (c) 2004-2005 John Goerzen, firstname.lastname@example.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
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
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.
|True if the file exists, regardless of what type it is.
This is even True if the given path is a broken symlink.
|Raise an error relating to actions on this class.
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
Default implementations of everything else are provided, returning
A default implementation of this is not currently present on Windows.
|Refers to file permissions, NOT the st_mode field from stat(2)
|Types that can open a HVIO object should be instances of this class.
You need only implement vOpen.
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
|forall a . HVFSStat a => HVFSStatEncap a|
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.
|Similar to withStat, but for the vOpen result.
|Re-exported types from other modules
|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.
|Produced by Haddock version 2.6.0|