NAME
   Filesys::Virtual::Async::Dispatcher - Multiple filesystems mounted on a
   single filesystem

SYNOPSIS
           #!/usr/bin/perl
           use strict; use warnings;
           use Fcntl qw( :DEFAULT :mode ); # S_IFREG S_IFDIR, O_SYNC O_LARGEFILE etc

           # uncomment this to enable debugging
           #sub Filesys::Virtual::Async::Dispatcher::DEBUG { 1 }

           use Filesys::Virtual::Async::Plain;
           use Filesys::Virtual::Async::Dispatcher;

           # create the root filesystem
           my $rootfs = Filesys::Virtual::Async::Plain->new( 'root' => $ENV{'PWD'} );

           # create the extra filesystems
           my $tmpfs = Filesys::Virtual::Async::Plain->new( 'root' => '/tmp' );
           my $procfs = Filesys::Virtual::Async::Plain->new( 'root' => '/proc' );

           # put it all together
           my $vfs = Filesys::Virtual::Async::Dispatcher->new( 'rootfs' => $rootfs );
           $vfs->mount( '/tmp', $tmpfs );
           $vfs->mount( '/tmp/proc', $procfs );

           # use $vfs as you wish!
           $vfs->readdir( '/tmp/proc', sub {       # should access the $procfs object
                   my $data = shift;
                   if ( defined $data ) {
                           foreach my $e ( @$data ) {
                                   print "entry in /tmp/proc -> $e\n";
                           }
                           print "end of listing for /tmp/proc\n";
                   } else {
                           print "error reading /tmp/proc\n";
                   }
           } );

ABSTRACT
   Using this module will enable you to "mount" objects onto a filesystem
   and properly map methods to them.

DESCRIPTION
   This module allows you to have arbitrary combinations of
   Filesys::Virtual::Async objects mounted and expose a single filesystem.
   The dispatcher will correctly map methods to the proper object based on
   their path in the filesystem. This works similar to the way linux
   manages mounts in a single "visible" filesystem.

   It might be a bit confusing on how the paths work at first. I'm sure
   with a bit of experimentation and looking at the documentation for the
   Filesys::Virtual::Async::XYZ subclass, you'll get it!

   This module makes extensive use of the functions in File::Spec to be
   portable, so it might trip you up if you are developing on a linux box
   and trying to mount '/foo' on a win32 box :)

 Initializing the dispatcher
   This constructor accepts either a hashref or a hash, valid options are:

  rootfs
   This sets the Filesys::Virtual::Async object that will manage the "root"
   filesystem.

   If this argument is undefined or not a proper subclass of
   Filesys::Virtual::Async new() will die.

 Methods
   There is only two methods you can use, because this module does nothing
   except dispatch method calls to the proper object.

  mount
   Mounts a new Filesys::Virtual::Async object on the rootfs. Takes two
   arguments: the path and the object.

   Returns true on success, false on failure.

   Possible failure reasons:

   undefined path
   undefined object or not proper subclass of Filesys::Virtual::Async
   another object already mounted on path

   NOTE: This module is currently a bit stupid. It will allow mounts on
   non-existent directories! This could cause weirdness when trying to do
   operations on the parent directory. This will be rectified in a future
   version, once I get my head around the callbacks and figure out a new
   API to mount with a callback...

  umount
   Unmounts a mounted Filesys::Virtual::Async object. Takes one argument:
   the path.

   Returns true on success, false on failure.

 Special Cases
   Currently, this module does a pretty good job of dispatching methods to
   the proper object. However, there are some methods which have exceptions
   to this rule.

  root
   Unimplemented, please do it directly on the object you are mounting onto
   the dispatcher.

  stat/lstat
   Array mode not supported because it would require extra munging on my
   part to get the paths right.

  link/symlink
   Linking across mounts is not supported because it would be crazy to keep
   the mapping in the dispatcher.

  rename/copy/move
   Doing these operations across mounts is not supported. Theoretically I
   could implement this in the dispatcher but it would have to happen in a
   future version :)

  rmtree
   Deleting a directory which contains another mount in it is not
   supported. This could be done but we would have to dig into the AIO code
   to make sure it stops deleting when it encounters the submount...

 Debugging
   You can enable debug mode which prints out some information ( and
   especially error messages ) by doing this:

           sub Filesys::Virtual::Async::Dispatcher::DEBUG () { 1 }
           use Filesys::Virtual::Async::Dispatcher;

EXPORT
   None.

SEE ALSO
   Filesys::Virtual::Async

SUPPORT
   You can find documentation for this module with the perldoc command.

       perldoc Filesys::Virtual::Async::Dispatcher

 Websites
   *   Search CPAN

       <http://search.cpan.org/dist/Filesys-Virtual-Async-Dispatcher>

   *   AnnoCPAN: Annotated CPAN documentation

       <http://annocpan.org/dist/Filesys-Virtual-Async-Dispatcher>

   *   CPAN Ratings

       <http://cpanratings.perl.org/d/Filesys-Virtual-Async-Dispatcher>

   *   CPAN Forum

       <http://cpanforum.com/dist/Filesys-Virtual-Async-Dispatcher>

   *   RT: CPAN's Request Tracker

       <http://rt.cpan.org/NoAuth/Bugs.html?Dist=Filesys-Virtual-Async-Disp
       atcher>

   *   CPANTS Kwalitee

       <http://cpants.perl.org/dist/overview/Filesys-Virtual-Async-Dispatch
       er>

   *   CPAN Testers Results

       <http://cpantesters.org/distro/F/Filesys-Virtual-Async-Dispatcher.ht
       ml>

   *   CPAN Testers Matrix

       <http://matrix.cpantesters.org/?dist=Filesys-Virtual-Async-Dispatche
       r>

   *   Git Source Code Repository

       This code is currently hosted on github.com under the account
       "apocalypse". Please feel free to browse it and pull from it, or
       whatever. If you want to contribute patches, please send me a diff
       or prod me to pull from your repository :)

       <http://github.com/apocalypse/perl-filesys-virtual-async-dispatcher>

 Bugs
   Please report any bugs or feature requests to
   "bug-filesys-virtual-async-dispatcher at rt.cpan.org", or through the
   web interface at
   <http://rt.cpan.org/NoAuth/ReportBug.html?Queue=Filesys-Virtual-Async-Di
   spatcher>. I will be notified, and then you'll automatically be notified
   of progress on your bug as I make changes.

AUTHOR
   Apocalypse <[email protected]>

   Props goes to xantus who got me motivated to write this :)

COPYRIGHT AND LICENSE
   Copyright 2010 by Apocalypse

   This library is free software; you can redistribute it and/or modify it
   under the same terms as Perl itself.

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