NAME

File::System - A virtual file system written in pure Perl

SYNOPSIS

  my $root = File::System->new("Real", root => '/var/chroot/foo');

  my $file = $root->lookup('/etc/fstab');
  print $file->lines;

DESCRIPTION

Important: This package is still in development, so some aspects of the API are likely to change.

The File::System library is intended to provide an interface to a file system. Generally, a file system is a heirarchical arrangement of records commonly found on most modern computers. This library attempts to generalize this idea as it pertains to loading and accessing these files. This is not meant to generalize on the specifics of file system implementations or get into hardware details.

The goal of this system is not to present the file system in a native way, but to provide the Perl program using it a simple hook into a potentially complex structure. Thus, certain file system module requirements may force unnatural or arbitrary constraints on the file system appearance. The most notable is that this implementation purposely does not address the concept of "volumes" except to state that such things should just be made parts of the file system under an artificial root.

This system is also still immature and certain aspects---notably the concept of "capabilities" and "permissions"---are absent. These may be added in future making existing file modules created to this system incompatible with future revisions. I will try to make sure that such things are "optional" such that the system can function in a crippled way without support for these future additions when they come, but I make guarantees.

FACTORY SYSTEM

The File::System module provides a central interface into loading other File::System modules. It provides a single method for instantiating a file system module:

$root = File::System->new($module_name, ...)

This will create and return the root file system object (i.e., an instance of File::System::Object) for the file system module named $module_name.

If the $module_name does not contain any colons, then it the package "File::System::$module_name" is loaded and the new method for that package is used to create the object. Otherwise, the $module_name is loaded and it's new method is used. For example,

  $fs = File::System->new('Real')
  # Module File::System::Real is loaded
  # Method File::System::Real->new is called
  
  $fs = File::System->new('My::File::System::Foo')
  # Module My::File::System::Foo is loaded
  # Method My::File::System::Foo->new is called

Any additional arguments passed to this method are then passed to the new method of the loaded package.

The returned object will behave according to the documentation available in File::System::Object.

BUGS

Lots of methods need to be added to the drivers. There are lots of questions that still need to be answerable. Such as, can a particular directory of a file system contain only certain kinds of files? The move, copy, and rename methods should be optional and methods for checking if they are proper should exist. Anyway, lots more informational methods need to be added.

The API is not set in stone yet. I'm going to start using it directly in another project of mine soon, so it is becoming solid. However, some aspects might be tweaked still. Hopefully, I will only be adding, but that doesn't much help a potential module author. I will put a note into the documentation when the API is locked in place. After that, I will require major version changes to change the API.

SEE ALSO

File::Find, File::System::Object

AUTHOR

Andrew Sterling Hanenkamp, <hanenkamp@users.sourceforge.net>

COPYRIGHT AND LICENSE

Copyright 2005 Andrew Sterling Hanenkamp. All Rights Reserved.

This software is distributed and licensed under the same terms as Perl itself.