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.