2 package Moose::Meta::Role;
9 use Scalar::Util 'blessed';
10 use B 'svref_2object';
12 our $VERSION = '0.10';
13 our $AUTHORITY = 'cpan:STEVAN';
15 use Moose::Meta::Class;
16 use Moose::Meta::Role::Method;
17 use Moose::Meta::Role::Method::Required;
19 use base 'Class::MOP::Module';
23 # I normally don't do this, but I am doing
24 # a whole bunch of meta-programmin in this
25 # module, so it just makes sense.
28 my $META = __PACKAGE__->meta;
30 ## ------------------------------------------------------------------
34 # since roles are lazy, we hold all the attributes
35 # of the individual role in 'statis' until which
36 # time when it is applied to a class. This means
37 # keeping a lot of things in hash maps, so we are
38 # using a little of that meta-programmin' magic
39 # here an saving lots of extra typin.
42 $META->add_attribute($_->{name} => (
43 reader => $_->{reader},
46 { name => 'excluded_roles_map', reader => 'get_excluded_roles_map' },
47 { name => 'attribute_map', reader => 'get_attribute_map' },
48 { name => 'required_methods', reader => 'get_required_methods_map' },
52 # many of these attributes above require similar
53 # functionality to support them, so we again use
54 # the wonders of meta-programmin' to deliver a
55 # very compact solution to this normally verbose
61 attr_reader => 'get_excluded_roles_map' ,
63 add => 'add_excluded_roles',
64 get_list => 'get_excluded_roles_list',
65 existence => 'excludes_role',
69 attr_reader => 'get_required_methods_map',
71 add => 'add_required_methods',
72 remove => 'remove_required_methods',
73 get_list => 'get_required_method_list',
74 existence => 'requires_method',
78 attr_reader => 'get_attribute_map',
80 get => 'get_attribute',
81 get_list => 'get_attribute_list',
82 existence => 'has_attribute',
83 remove => 'remove_attribute',
88 my $attr_reader = $action->{attr_reader};
89 my $methods = $action->{methods};
91 $META->add_method($methods->{add} => sub {
92 my ($self, @values) = @_;
93 $self->$attr_reader->{$_} = undef foreach @values;
94 }) if exists $methods->{add};
96 $META->add_method($methods->{get_list} => sub {
98 keys %{$self->$attr_reader};
99 }) if exists $methods->{get_list};
101 $META->add_method($methods->{get} => sub {
102 my ($self, $name) = @_;
103 $self->$attr_reader->{$name}
104 }) if exists $methods->{get};
106 $META->add_method($methods->{existence} => sub {
107 my ($self, $name) = @_;
108 exists $self->$attr_reader->{$name} ? 1 : 0;
109 }) if exists $methods->{existence};
111 $META->add_method($methods->{remove} => sub {
112 my ($self, @values) = @_;
113 delete $self->$attr_reader->{$_} foreach @values;
114 }) if exists $methods->{remove};
117 ## some things don't always fit, so they go here ...
123 if (scalar @_ == 1 && ref($_[0]) eq 'HASH') {
129 $self->get_attribute_map->{$name} = $attr_desc;
132 sub _clean_up_required_methods {
134 foreach my $method ($self->get_required_method_list) {
135 $self->remove_required_methods($method)
136 if $self->has_method($method);
140 ## ------------------------------------------------------------------
143 $META->add_attribute($_->{name} => (
144 reader => $_->{reader},
145 default => sub { {} }
147 { name => 'before_method_modifiers', reader => 'get_before_method_modifiers_map' },
148 { name => 'after_method_modifiers', reader => 'get_after_method_modifiers_map' },
149 { name => 'around_method_modifiers', reader => 'get_around_method_modifiers_map' },
150 { name => 'override_method_modifiers', reader => 'get_override_method_modifiers_map' },
154 # the before/around/after method modifiers are
155 # stored by name, but there can be many methods
156 # then associated with that name. So again we have
157 # lots of similar functionality, so we can do some
158 # meta-programmin' and save some time.
161 foreach my $modifier_type (qw[ before around after ]) {
163 my $attr_reader = "get_${modifier_type}_method_modifiers_map";
165 $META->add_method("get_${modifier_type}_method_modifiers" => sub {
166 my ($self, $method_name) = @_;
167 @{$self->$attr_reader->{$method_name}};
170 $META->add_method("has_${modifier_type}_method_modifiers" => sub {
171 my ($self, $method_name) = @_;
173 # for now we assume that if it exists,..
174 # it has at least one modifier in it
175 (exists $self->$attr_reader->{$method_name}) ? 1 : 0;
178 $META->add_method("add_${modifier_type}_method_modifier" => sub {
179 my ($self, $method_name, $method) = @_;
181 $self->$attr_reader->{$method_name} = []
182 unless exists $self->$attr_reader->{$method_name};
184 my $modifiers = $self->$attr_reader->{$method_name};
187 # check to see that we aren't adding the
188 # same code twice. We err in favor of the
189 # first on here, this may not be as expected
190 foreach my $modifier (@{$modifiers}) {
191 return if $modifier == $method;
194 push @{$modifiers} => $method;
199 ## ------------------------------------------------------------------
200 ## override method mofidiers
203 # these are a little different because there
204 # can only be one per name, whereas the other
205 # method modifiers can have multiples.
208 sub add_override_method_modifier {
209 my ($self, $method_name, $method) = @_;
210 (!$self->has_method($method_name))
211 || confess "Cannot add an override of method '$method_name' " .
212 "because there is a local version of '$method_name'";
213 $self->get_override_method_modifiers_map->{$method_name} = $method;
216 sub has_override_method_modifier {
217 my ($self, $method_name) = @_;
219 # for now we assume that if it exists,..
220 # it has at least one modifier in it
221 (exists $self->get_override_method_modifiers_map->{$method_name}) ? 1 : 0;
224 sub get_override_method_modifier {
225 my ($self, $method_name) = @_;
226 $self->get_override_method_modifiers_map->{$method_name};
229 ## general list accessor ...
231 sub get_method_modifier_list {
232 my ($self, $modifier_type) = @_;
233 my $accessor = "get_${modifier_type}_method_modifiers_map";
234 keys %{$self->$accessor};
237 ## ------------------------------------------------------------------
240 __PACKAGE__->meta->add_attribute('roles' => (
241 reader => 'get_roles',
242 default => sub { [] }
246 my ($self, $role) = @_;
247 (blessed($role) && $role->isa('Moose::Meta::Role'))
248 || confess "Roles must be instances of Moose::Meta::Role";
249 push @{$self->get_roles} => $role;
252 sub calculate_all_roles {
259 $_->calculate_all_roles
260 } @{ $self->get_roles });
264 my ($self, $role_name) = @_;
266 || confess "You must supply a role name to look for";
267 # if we are it,.. then return true
268 return 1 if $role_name eq $self->name;
269 # otherwise.. check our children
270 foreach my $role (@{$self->get_roles}) {
271 return 1 if $role->does_role($role_name);
276 ## ------------------------------------------------------------------
279 sub method_metaclass { 'Moose::Meta::Role::Method' }
282 # this is an UGLY hack
285 $self->{'%!methods'} ||= {};
286 $self->Moose::Meta::Class::get_method_map()
290 # Yes, this is a really really UGLY hack
291 # but it works, and until I can figure
292 # out a better way, this is gonna be it.
294 sub get_method { (shift)->Moose::Meta::Class::get_method(@_) }
295 sub has_method { (shift)->Moose::Meta::Class::has_method(@_) }
296 sub alias_method { (shift)->Moose::Meta::Class::alias_method(@_) }
297 sub get_method_list {
300 } (shift)->Moose::Meta::Class::get_method_list(@_)
303 sub find_method_by_name { (shift)->get_method(@_) }
305 ## ------------------------------------------------------------------
307 ## ------------------------------------------------------------------
309 my $anon_counter = 0;
312 my ($self, $other) = @_;
314 unless ($other->isa('Moose::Meta::Class') || $other->isa('Moose::Meta::Role')) {
316 # Runtime Role mixins
319 # We really should do this better, and
320 # cache the results of our efforts so
321 # that we don't need to repeat them.
323 my $pkg_name = __PACKAGE__ . "::__RUNTIME_ROLE_ANON_CLASS__::" . $anon_counter++;
324 eval "package " . $pkg_name . "; our \$VERSION = '0.00';";
329 $other = Moose::Meta::Class->initialize($pkg_name);
330 $other->superclasses(blessed($object));
332 bless $object => $pkg_name;
335 $self->_check_excluded_roles($other);
336 $self->_check_required_methods($other);
338 $self->_apply_attributes($other);
339 $self->_apply_methods($other);
341 $self->_apply_override_method_modifiers($other);
342 $self->_apply_before_method_modifiers($other);
343 $self->_apply_around_method_modifiers($other);
344 $self->_apply_after_method_modifiers($other);
346 $other->add_role($self);
350 my ($class, @roles) = @_;
352 my $pkg_name = __PACKAGE__ . "::__COMPOSITE_ROLE_SANDBOX__::" . $anon_counter++;
353 eval "package " . $pkg_name . "; our \$VERSION = '0.00';";
356 my $combined = $class->initialize($pkg_name);
358 foreach my $role (@roles) {
359 $role->apply($combined);
362 $combined->_clean_up_required_methods;
367 ## ------------------------------------------------------------------
369 ## applying a role to a class ...
371 sub _check_excluded_roles {
372 my ($self, $other) = @_;
373 if ($other->excludes_role($self->name)) {
374 confess "Conflict detected: " . $other->name . " excludes role '" . $self->name . "'";
376 foreach my $excluded_role_name ($self->get_excluded_roles_list) {
377 if ($other->does_role($excluded_role_name)) {
378 confess "The class " . $other->name . " does the excluded role '$excluded_role_name'";
381 if ($other->isa('Moose::Meta::Role')) {
382 $other->add_excluded_roles($excluded_role_name);
384 # else -> ignore it :)
389 sub _check_required_methods {
390 my ($self, $other) = @_;
392 # we might need to move this down below the
393 # the attributes so that we can require any
394 # attribute accessors. However I am thinking
395 # that maybe those are somehow exempt from
396 # the require methods stuff.
397 foreach my $required_method_name ($self->get_required_method_list) {
399 unless ($other->find_method_by_name($required_method_name)) {
400 if ($other->isa('Moose::Meta::Role')) {
401 $other->add_required_methods($required_method_name);
404 confess "'" . $self->name . "' requires the method '$required_method_name' " .
405 "to be implemented by '" . $other->name . "'";
410 # we need to make sure that the method is
411 # not a method modifier, because those do
412 # not satisfy the requirements ...
413 my $method = $other->find_method_by_name($required_method_name);
415 # check if it is a generated accessor ...
416 (!$method->isa('Class::MOP::Method::Accessor'))
417 || confess "'" . $self->name . "' requires the method '$required_method_name' " .
418 "to be implemented by '" . $other->name . "', the method is only an attribute accessor";
421 # All other tests here have been removed, they were tests
422 # for overriden methods and before/after/around modifiers.
423 # But we realized that for classes any overriden or modified
424 # methods would be backed by a real method of that name
425 # (and therefore meet the requirement). And for roles, the
426 # overriden and modified methods are "in statis" and so would
427 # not show up in this test anyway (and as a side-effect they
428 # would not fufill the requirement, which is exactly what we
429 # want them to do anyway).
435 sub _apply_attributes {
436 my ($self, $other) = @_;
437 foreach my $attribute_name ($self->get_attribute_list) {
438 # it if it has one already
439 if ($other->has_attribute($attribute_name) &&
440 # make sure we haven't seen this one already too
441 $other->get_attribute($attribute_name) != $self->get_attribute($attribute_name)) {
442 # see if we are being composed
444 if ($other->isa('Moose::Meta::Role')) {
445 # all attribute conflicts between roles
446 # result in an immediate fatal error
447 confess "Role '" . $self->name . "' has encountered an attribute conflict " .
448 "during composition. This is fatal error and cannot be disambiguated.";
451 # but if this is a class, we
452 # can safely skip adding the
453 # attribute to the class
459 # this is kinda ugly ...
460 if ($other->isa('Moose::Meta::Class')) {
461 $other->_process_attribute(
463 %{$self->get_attribute($attribute_name)}
467 $other->add_attribute(
469 $self->get_attribute($attribute_name)
477 my ($self, $other) = @_;
478 foreach my $method_name ($self->get_method_list) {
479 # it if it has one already
480 if ($other->has_method($method_name) &&
481 # and if they are not the same thing ...
482 $other->get_method($method_name)->body != $self->get_method($method_name)->body) {
483 # see if we are composing into a role
484 if ($other->isa('Moose::Meta::Role')) {
485 # method conflicts between roles result
486 # in the method becoming a requirement
487 $other->add_required_methods($method_name);
489 # we have to remove the method from our
490 # role, if this is being called from combine()
491 # which means the meta is an anon class
492 # this *may* cause problems later, but it
493 # is probably fairly safe to assume that
494 # anon classes will only be used internally
495 # or by people who know what they are doing
496 $other->Moose::Meta::Class::remove_method($method_name)
497 if $other->name =~ /__COMPOSITE_ROLE_SANDBOX__/;
504 # add it, although it could be overriden
505 $other->alias_method(
507 $self->get_method($method_name)
513 sub _apply_override_method_modifiers {
514 my ($self, $other) = @_;
515 foreach my $method_name ($self->get_method_modifier_list('override')) {
516 # it if it has one already then ...
517 if ($other->has_method($method_name)) {
518 # if it is being composed into another role
519 # we have a conflict here, because you cannot
520 # combine an overriden method with a locally
522 if ($other->isa('Moose::Meta::Role')) {
523 confess "Role '" . $self->name . "' has encountered an 'override' method conflict " .
524 "during composition (A local method of the same name as been found). This " .
528 # if it is a class, then we
529 # just ignore this here ...
534 # if no local method is found, then we
535 # must check if we are a role or class
536 if ($other->isa('Moose::Meta::Role')) {
537 # if we are a role, we need to make sure
538 # we dont have a conflict with the role
539 # we are composing into
540 if ($other->has_override_method_modifier($method_name) &&
541 $other->get_override_method_modifier($method_name) != $self->get_override_method_modifier($method_name)) {
542 confess "Role '" . $self->name . "' has encountered an 'override' method conflict " .
543 "during composition (Two 'override' methods of the same name encountered). " .
544 "This is fatal error.";
547 # if there is no conflict,
548 # just add it to the role
549 $other->add_override_method_modifier(
551 $self->get_override_method_modifier($method_name)
556 # if this is not a role, then we need to
557 # find the original package of the method
558 # so that we can tell the class were to
559 # find the right super() method
560 my $method = $self->get_override_method_modifier($method_name);
561 my $package = svref_2object($method)->GV->STASH->NAME;
562 # if it is a class, we just add it
563 $other->add_override_method_modifier($method_name, $method, $package);
569 sub _apply_method_modifiers {
570 my ($self, $modifier_type, $other) = @_;
571 my $add = "add_${modifier_type}_method_modifier";
572 my $get = "get_${modifier_type}_method_modifiers";
573 foreach my $method_name ($self->get_method_modifier_list($modifier_type)) {
577 ) foreach $self->$get($method_name);
581 sub _apply_before_method_modifiers { (shift)->_apply_method_modifiers('before' => @_) }
582 sub _apply_around_method_modifiers { (shift)->_apply_method_modifiers('around' => @_) }
583 sub _apply_after_method_modifiers { (shift)->_apply_method_modifiers('after' => @_) }
593 Moose::Meta::Role - The Moose Role metaclass
597 Please see L<Moose::Role> for more information about roles.
598 For the most part, this has no user-serviceable parts inside
599 this module. It's API is still subject to some change (although
600 probably not that much really).
638 =item B<add_excluded_roles>
640 =item B<excludes_role>
642 =item B<get_excluded_roles_list>
644 =item B<get_excluded_roles_map>
646 =item B<calculate_all_roles>
652 =item B<method_metaclass>
654 =item B<find_method_by_name>
660 =item B<alias_method>
662 =item B<get_method_list>
664 =item B<get_method_map>
670 =item B<add_attribute>
672 =item B<has_attribute>
674 =item B<get_attribute>
676 =item B<get_attribute_list>
678 =item B<get_attribute_map>
680 =item B<remove_attribute>
686 =item B<add_required_methods>
688 =item B<remove_required_methods>
690 =item B<get_required_method_list>
692 =item B<get_required_methods_map>
694 =item B<requires_method>
700 =item B<add_after_method_modifier>
702 =item B<add_around_method_modifier>
704 =item B<add_before_method_modifier>
706 =item B<add_override_method_modifier>
712 =item B<has_after_method_modifiers>
714 =item B<has_around_method_modifiers>
716 =item B<has_before_method_modifiers>
718 =item B<has_override_method_modifier>
724 =item B<get_after_method_modifiers>
726 =item B<get_around_method_modifiers>
728 =item B<get_before_method_modifiers>
730 =item B<get_method_modifier_list>
736 =item B<get_override_method_modifier>
738 =item B<get_after_method_modifiers_map>
740 =item B<get_around_method_modifiers_map>
742 =item B<get_before_method_modifiers_map>
744 =item B<get_override_method_modifiers_map>
750 All complex software has bugs lurking in it, and this module is no
751 exception. If you find a bug please either email me, or add the bug
756 Stevan Little E<lt>stevan@iinteractive.comE<gt>
758 =head1 COPYRIGHT AND LICENSE
760 Copyright 2006, 2007 by Infinity Interactive, Inc.
762 L<http://www.iinteractive.com>
764 This library is free software; you can redistribute it and/or modify
765 it under the same terms as Perl itself.