package Test2::Util::ExternalMeta; use strict; use warnings; our $VERSION = '1.302190'; use Carp qw/croak/; sub META_KEY() { '_meta' } our @EXPORT = qw/meta set_meta get_meta delete_meta/; BEGIN { require Exporter; our @ISA = qw(Exporter) } sub set_meta { my $self = shift; my ($key, $value) = @_; validate_key($key); $self->{+META_KEY} ||= {}; $self->{+META_KEY}->{$key} = $value; } sub get_meta { my $self = shift; my ($key) = @_; validate_key($key); my $meta = $self->{+META_KEY} or return undef; return $meta->{$key}; } sub delete_meta { my $self = shift; my ($key) = @_; validate_key($key); my $meta = $self->{+META_KEY} or return undef; delete $meta->{$key}; } sub meta { my $self = shift; my ($key, $default) = @_; validate_key($key); my $meta = $self->{+META_KEY}; return undef unless $meta || defined($default); unless($meta) { $meta = {}; $self->{+META_KEY} = $meta; } $meta->{$key} = $default if defined($default) && !defined($meta->{$key}); return $meta->{$key}; } sub validate_key { my $key = shift; return if $key && !ref($key); my $render_key = defined($key) ? "'$key'" : 'undef'; croak "Invalid META key: $render_key, keys must be true, and may not be references"; } 1; __END__ =pod =encoding UTF-8 =head1 NAME Test2::Util::ExternalMeta - Allow third party tools to safely attach meta-data to your instances. =head1 DESCRIPTION This package lets you define a clear, and consistent way to allow third party tools to attach meta-data to your instances. If your object consumes this package, and imports its methods, then third party meta-data has a safe place to live. =head1 SYNOPSIS package My::Object; use strict; use warnings; use Test2::Util::ExternalMeta qw/meta get_meta set_meta delete_meta/; ... Now to use it: my $inst = My::Object->new; $inst->set_meta(foo => 'bar'); my $val = $inst->get_meta('foo'); =head1 WHERE IS THE DATA STORED? This package assumes your instances are blessed hashrefs, it will not work if that is not true. It will store all meta-data in the C<_meta> key on your objects hash. If your object makes use of the C<_meta> key in its underlying hash, then there is a conflict and you cannot use this package. =head1 EXPORTS =over 4 =item $val = $obj->meta($key) =item $val = $obj->meta($key, $default) This will get the value for a specified meta C<$key>. Normally this will return C when there is no value for the C<$key>, however you can specify a C<$default> value to set when no value is already set. =item $val = $obj->get_meta($key) This will get the value for a specified meta C<$key>. This does not have the C<$default> overhead that C does. =item $val = $obj->delete_meta($key) This will remove the value of a specified meta C<$key>. The old C<$val> will be returned. =item $obj->set_meta($key, $val) Set the value of a specified meta C<$key>. =back =head1 META-KEY RESTRICTIONS Meta keys must be defined, and must be true when used as a boolean. Keys may not be references. You are free to stringify a reference C<"$ref"> for use as a key, but this package will not stringify it for you. =head1 SOURCE The source code repository for Test2 can be found at F. =head1 MAINTAINERS =over 4 =item Chad Granum Eexodist@cpan.orgE =back =head1 AUTHORS =over 4 =item Chad Granum Eexodist@cpan.orgE =back =head1 COPYRIGHT Copyright 2020 Chad Granum Eexodist@cpan.orgE. This program is free software; you can redistribute it and/or modify it under the same terms as Perl itself. See F =cut