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1 | package Moose::Util::MetaRole; |
2 | |
3 | use strict; |
4 | use warnings; |
5 | |
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6 | our $VERSION = '0.89_01'; |
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7 | $VERSION = eval $VERSION; |
8 | our $AUTHORITY = 'cpan:STEVAN'; |
9 | |
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10 | use List::MoreUtils qw( all ); |
11 | |
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12 | my @Classes = qw( constructor_class destructor_class error_class ); |
13 | |
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14 | sub apply_metaclass_roles { |
15 | my %options = @_; |
16 | |
17 | my $for = $options{for_class}; |
18 | |
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19 | my %old_classes = map { $_ => Class::MOP::class_of($for)->$_ } |
20 | grep { Class::MOP::class_of($for)->can($_) } |
21 | @Classes; |
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22 | |
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23 | my $meta = _make_new_metaclass( $for, \%options ); |
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24 | |
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25 | for my $c ( grep { $meta->can($_) } @Classes ) { |
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26 | if ( $options{ $c . '_roles' } ) { |
27 | my $class = _make_new_class( |
28 | $meta->$c(), |
29 | $options{ $c . '_roles' } |
30 | ); |
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31 | |
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32 | $meta->$c($class); |
33 | } |
34 | else { |
35 | $meta->$c( $old_classes{$c} ); |
36 | } |
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37 | } |
38 | |
39 | return $meta; |
40 | } |
41 | |
42 | sub _make_new_metaclass { |
43 | my $for = shift; |
44 | my $options = shift; |
45 | |
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46 | return Class::MOP::class_of($for) |
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47 | unless grep { exists $options->{ $_ . '_roles' } } |
48 | qw( |
49 | metaclass |
50 | attribute_metaclass |
51 | method_metaclass |
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52 | wrapped_method_metaclass |
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53 | instance_metaclass |
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54 | application_to_class_class |
55 | application_to_role_class |
56 | application_to_instance_class |
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57 | ); |
58 | |
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59 | my $old_meta = Class::MOP::class_of($for); |
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60 | my $new_metaclass |
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61 | = _make_new_class( ref $old_meta, $options->{metaclass_roles} ); |
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62 | |
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63 | # This could get called for a Moose::Meta::Role as well as a Moose::Meta::Class |
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64 | my %classes = map { |
65 | $_ => _make_new_class( $old_meta->$_(), $options->{ $_ . '_roles' } ) |
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66 | } |
67 | grep { $old_meta->can($_) } |
68 | qw( |
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69 | attribute_metaclass |
70 | method_metaclass |
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71 | wrapped_method_metaclass |
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72 | instance_metaclass |
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73 | application_to_class_class |
74 | application_to_role_class |
75 | application_to_instance_class |
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76 | ); |
77 | |
78 | return $new_metaclass->reinitialize( $for, %classes ); |
79 | } |
80 | |
81 | sub apply_base_class_roles { |
82 | my %options = @_; |
83 | |
84 | my $for = $options{for_class}; |
85 | |
95f64261 |
86 | my $meta = Class::MOP::class_of($for); |
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87 | |
88 | my $new_base = _make_new_class( |
89 | $for, |
90 | $options{roles}, |
91 | [ $meta->superclasses() ], |
92 | ); |
93 | |
94 | $meta->superclasses($new_base) |
95 | if $new_base ne $meta->name(); |
96 | } |
97 | |
98 | sub _make_new_class { |
99 | my $existing_class = shift; |
100 | my $roles = shift; |
101 | my $superclasses = shift || [$existing_class]; |
102 | |
103 | return $existing_class unless $roles; |
104 | |
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105 | my $meta = Class::MOP::Class->initialize($existing_class); |
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106 | |
107 | return $existing_class |
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108 | if $meta->can('does_role') && all { $meta->does_role($_) } |
109 | grep { !ref $_ } @{$roles}; |
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110 | |
111 | return Moose::Meta::Class->create_anon_class( |
112 | superclasses => $superclasses, |
113 | roles => $roles, |
114 | cache => 1, |
115 | )->name(); |
116 | } |
117 | |
118 | 1; |
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119 | |
120 | __END__ |
121 | |
122 | =head1 NAME |
123 | |
124 | Moose::Util::MetaRole - Apply roles to any metaclass, as well as the object base class |
125 | |
126 | =head1 SYNOPSIS |
127 | |
128 | package MyApp::Moose; |
129 | |
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130 | use Moose (); |
131 | use Moose::Exporter; |
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132 | use Moose::Util::MetaRole; |
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133 | |
134 | use MyApp::Role::Meta::Class; |
135 | use MyApp::Role::Meta::Method::Constructor; |
136 | use MyApp::Role::Object; |
137 | |
138 | Moose::Exporter->setup_import_methods( also => 'Moose' ); |
139 | |
140 | sub init_meta { |
141 | shift; |
142 | my %options = @_; |
143 | |
144 | Moose->init_meta(%options); |
145 | |
146 | Moose::Util::MetaRole::apply_metaclass_roles( |
147 | for_class => $options{for_class}, |
148 | metaclass_roles => ['MyApp::Role::Meta::Class'], |
149 | constructor_class_roles => ['MyApp::Role::Meta::Method::Constructor'], |
150 | ); |
151 | |
152 | Moose::Util::MetaRole::apply_base_class_roles( |
153 | for_class => $options{for_class}, |
154 | roles => ['MyApp::Role::Object'], |
155 | ); |
156 | |
157 | return $options{for_class}->meta(); |
158 | } |
159 | |
160 | =head1 DESCRIPTION |
161 | |
162 | This utility module is designed to help authors of Moose extensions |
163 | write extensions that are able to cooperate with other Moose |
164 | extensions. To do this, you must write your extensions as roles, which |
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165 | can then be dynamically applied to the caller's metaclasses. |
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166 | |
167 | This module makes sure to preserve any existing superclasses and roles |
168 | already set for the meta objects, which means that any number of |
169 | extensions can apply roles in any order. |
170 | |
171 | =head1 USAGE |
172 | |
173 | B<It is very important that you only call this module's functions when |
174 | your module is imported by the caller>. The process of applying roles |
175 | to the metaclass reinitializes the metaclass object, which wipes out |
176 | any existing attributes already defined. However, as long as you do |
177 | this when your module is imported, the caller should not have any |
178 | attributes defined yet. |
179 | |
180 | The easiest way to ensure that this happens is to use |
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181 | L<Moose::Exporter>, which can generate the appropriate C<init_meta> |
182 | method for you, and make sure it is called when imported. |
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183 | |
184 | =head1 FUNCTIONS |
185 | |
186 | This module provides two functions. |
187 | |
188 | =head2 apply_metaclass_roles( ... ) |
189 | |
190 | This function will apply roles to one or more metaclasses for the |
191 | specified class. It accepts the following parameters: |
192 | |
193 | =over 4 |
194 | |
195 | =item * for_class => $name |
196 | |
197 | This specifies the class for which to alter the meta classes. |
198 | |
199 | =item * metaclass_roles => \@roles |
200 | |
201 | =item * attribute_metaclass_roles => \@roles |
202 | |
203 | =item * method_metaclass_roles => \@roles |
204 | |
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205 | =item * wrapped_method_metaclass_roles => \@roles |
206 | |
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207 | =item * instance_metaclass_roles => \@roles |
208 | |
209 | =item * constructor_class_roles => \@roles |
210 | |
211 | =item * destructor_class_roles => \@roles |
212 | |
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213 | =item * application_to_class_class_roles => \@roles |
214 | |
215 | =item * application_to_role_class_roles => \@roles |
216 | |
217 | =item * application_to_instance_class_roles => \@roles |
218 | |
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219 | These parameter all specify one or more roles to be applied to the |
220 | specified metaclass. You can pass any or all of these parameters at |
221 | once. |
222 | |
223 | =back |
224 | |
225 | =head2 apply_base_class_roles( for_class => $class, roles => \@roles ) |
226 | |
227 | This function will apply the specified roles to the object's base class. |
228 | |
229 | =head1 AUTHOR |
230 | |
231 | Dave Rolsky E<lt>autarch@urth.orgE<gt> |
232 | |
233 | =head1 COPYRIGHT AND LICENSE |
234 | |
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235 | Copyright 2009 by Infinity Interactive, Inc. |
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236 | |
237 | L<http://www.iinteractive.com> |
238 | |
239 | This library is free software; you can redistribute it and/or modify |
240 | it under the same terms as Perl itself. |
241 | |
242 | =cut |