Mixin::ExtraFields::Driver::HashGuts(3)

NAME
Mixin::ExtraFields::Driver::HashGuts - store extras in a hashy object's guts

VERSION
version 0.100971

SYNOPSIS
  package Your::HashBased::Class;

  use Mixin::ExtraFields -fields => { driver => 'HashGuts' };

DESCRIPTION
This driver class implements an extremely simple storage mechanism: extras are stored on the object on which the mixed-in methods are called. By default, they are stored under the key returned by the "default_has_key" method, but this can be changed by providing a "hash_key" argument to the driver configuration, like so:

  use Mixin::ExtraFields -fields => {
    driver => { class => 'HashGuts', hash_key => "\0Something\0Wicked\0" }
  };

METHODS
In addition to the methods required by Mixin::ExtraFields::Driver, the following methods are provided:

  hash_key
  my $key = $driver->hash_key;

This method returns the key where the driver will store its extras.

  default_hash_key
If no "hash_key" argument is given for the driver, this method is called during driver initialization. It will return a unique string to be used as the hash key.

  storage
This method returns the hashref of storage used for extras. Individual objects get weak references to their id within this hashref.

  storage_for
  my $stash = $driver->storage_for($object, $id);

This method returns the hashref to use to store extras for the given object and id. This hashref is stored on both the hash-based object (in its "hash_key" entry) and on the driver (in the entry for $id in its "storage" hash).

All objects with the same id should end up with the same hash in their "hash_key" field. None of these references are weakened, which means two things: first, even if all objects with a given id go out of scope, future objects with that id will retain the original extras; secondly, memory used to store extras is never reclaimed. If this is a problem, use a more sophisticated driver.

AUTHOR
This code was written by Ricardo SIGNES. His code in 2006 was sponsored by Listbox.

COPYRIGHT AND LICENSE
Copyright (C) 2006, Ricardo SIGNES. This code is free software, and is available under the same terms as perl itself.