/ 
Mixin-ExtraFields-0.140003
River stage one • 4 direct dependents • 9 total dependents
/ Mixin::ExtraFields::Driver::HashGuts

NAME

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

VERSION

version 0.140003

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" }
};

PERL VERSION

This library should run on perls released even a long time ago. It should work on any version of perl released in the last five years.

Although it may work on older versions of perl, no guarantee is made that the minimum required version will not be increased. The version may be increased for any reason, and there is no promise that patches will be accepted to lower the minimum required perl.

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

Ricardo Signes <cpan@semiotic.systems>

COPYRIGHT AND LICENSE

This software is copyright (c) 2022 by Ricardo Signes.

This is free software; you can redistribute it and/or modify it under the same terms as the Perl 5 programming language system itself.