NAME
    File::ShareDir - Locate per-dist and per-module shared files

SYNOPSIS
      use File::SharedDir ':ALL';
  
      # Where are distribution-level shared data files kept
      $dir = dist_dir('File-ShareDir');
  
      # Where are module-level shared data files kept
      $dir = module_dir('File::ShareDir');
  
      # Find a specific file in our dist/module shared dir
      $file = dist_file(  'File-ShareDir',  'file/name.txt');
      $file = module_file('File::ShareDir', 'file/name.txt');
  
      # Like module_file, but search up the inheritance tree
      $file = class_file( 'Foo::Bar', 'file/name.txt' );

DESCRIPTION
    The intent of File::ShareDir is to provide a companion to
    Class::Inspector and File::HomeDir, modules that take a process that is
    well-known by advanced Perl developers but gets a little tricky, and
    make it more available to the larger Perl community.

    Quite often you want or need your Perl module (CPAN or otherwise) to
    have access to a large amount of read-only data that is stored on the
    file-system at run-time.

    On a linux-like system, this would be in a place such as /usr/share,
    however Perl runs on a wide variety of different systems, and so the use
    of any one location is unreliable.

    Perl provides a little-known method for doing this, but almost nobody is
    aware that it exists. As a result, module authors often go through some
    very strange ways to make the data available to their code.

    The most common of these is to dump the data out to an enormous Perl
    data structure and save it into the module itself. The result are
    enormous multi-megabyte .pm files that chew up a lot of memory
    needlessly.

    Another method is to put the data "file" after the __DATA__ compiler tag
    and limit yourself to access as a filehandle.

    The problem to solve is really quite simple.

      1. Write the data files to the system at install time.
  
      2. Know where you put them at run-time.

    Perl's install system creates an "auto" directory for both every
    distribution and for every module file.

    These are used by a couple of different auto-loading systems to store
    code fragments generated at install time, and various other modules
    written by the Perl "ancient masters".

    But the same mechanism is available to any dist or module to store any
    sort of data.

  Using Data in your Module
    "File::ShareDir" forms one half of a two part solution.

    Once the files have been installed to the correct directory, you can use
    "File::ShareDir" to find your files again after the installation.

    For the installation half of the solution, see Module::Install and its
    "install_share" directive.

FUNCTIONS
    "File::ShareDir" provides four functions for locating files and
    directories.

    For greater maintainability, none of these are exported by default and
    you are expected to name the ones you want at use-time, or provide the
    ':ALL' tag. All of the following are equivalent.

      # Load but don't import, and then call directly
      use File::ShareDir;
      $dir = File::ShareDir::dist_dir('My-Dist');
  
      # Import a single function
      use File::ShareDir 'dist_dir';
      dist_dir('My-Dist');
  
      # Import all the functions
      use File::ShareDir ':ALL';
      dist_dir('My-Dist');

    All of the functions will check for you that the dir/file actually
    exists, and that you have read permissions, or they will throw an
    exception.

  dist_dir
      # Get a distribution's shared files directory
      my $dir = dist_dir('My-Distribution');

    The "dist_dir" function takes a single parameter of the name of an
    installed (CPAN or otherwise) distribution, and locates the shared data
    directory created at install time for it.

    Returns the directory path as a string, or dies if it cannot be located
    or is not readable.

  module_dir
      # Get a module's shared files directory
      my $dir = module_dir('My::Module');

    The "module_dir" function takes a single parameter of the name of an
    installed (CPAN or otherwise) module, and locates the shared data
    directory created at install time for it.

    In order to find the directory, the module must be loaded when calling
    this function.

    Returns the directory path as a string, or dies if it cannot be located
    or is not readable.

  dist_file
      # Find a file in our distribution shared dir
      my $dir = dist_file('My-Distribution', 'file/name.txt');

    The "dist_file" function takes two params of the distribution name and
    file name, locates the dist dir, and then finds the file within it,
    verifying that the file actually exists, and that it is readable.

    The filename should be a relative path in the format of your local
    filesystem. It will simply added to the directory using File::Spec's
    "catfile" method.

    Returns the file path as a string, or dies if the file or the dist's
    directory cannot be located, or the file is not readable.

  module_file
      # Find a file in our module shared dir
      my $dir = module_file('My::Module', 'file/name.txt');

    The "module_file" function takes two params of the module name and file
    name. It locates the module dir, and then finds the file within it,
    verifying that the file actually exists, and that it is readable.

    In order to find the directory, the module must be loaded when calling
    this function.

    The filename should be a relative path in the format of your local
    filesystem. It will simply added to the directory using File::Spec's
    "catfile" method.

    Returns the file path as a string, or dies if the file or the dist's
    directory cannot be located, or the file is not readable.

  class_file
      # Find a file in our module shared dir, or in our parent class
      my $dir = class_file('My::Module', 'file/name.txt');

    The "module_file" function takes two params of the module name and file
    name. It locates the module dir, and then finds the file within it,
    verifying that the file actually exists, and that it is readable.

    In order to find the directory, the module must be loaded when calling
    this function.

    The filename should be a relative path in the format of your local
    filesystem. It will simply added to the directory using File::Spec's
    "catfile" method.

    If the file is NOT found for that module, "class_file" will scan up the
    module's @ISA tree, looking for the file in all of the parent classes.

    This allows you to, in effect, "subclass" shared files.

    Returns the file path as a string, or dies if the file or the dist's
    directory cannot be located, or the file is not readable.

SUPPORT
    Bugs should always be submitted via the CPAN bug tracker

    <http://rt.cpan.org/NoAuth/ReportBug.html?Queue=File-ShareDir>

    For other issues, contact the maintainer.

AUTHOR
    Adam Kennedy <adamk@cpan.org>

SEE ALSO
    File::HomeDir, Module::Install, Module::Install::Share

COPYRIGHT
    Copyright 2005 - 2008 Adam Kennedy.

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

    The full text of the license can be found in the LICENSE file included
    with this module.