1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
|
package Test2::Util::ExternalMeta;
use strict;
use warnings;
our $VERSION = '1.302103';
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<undef> 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<meta()> 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<http://github.com/Test-More/test-more/>.
=head1 MAINTAINERS
=over 4
=item Chad Granum E<lt>exodist@cpan.orgE<gt>
=back
=head1 AUTHORS
=over 4
=item Chad Granum E<lt>exodist@cpan.orgE<gt>
=back
=head1 COPYRIGHT
Copyright 2017 Chad Granum E<lt>exodist@cpan.orgE<gt>.
This program is free software; you can redistribute it and/or
modify it under the same terms as Perl itself.
See F<http://dev.perl.org/licenses/>
=cut
|
