2 package Moose::Meta::Role;
9 use Scalar::Util 'blessed';
10 use B 'svref_2object';
12 our $VERSION = '0.09';
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);
414 # check if it is an override or a generated accessor ..
415 ($method->isa('Class::MOP::Method::Accessor'))
416 && confess "'" . $self->name . "' requires the method '$required_method_name' " .
417 "to be implemented by '" . $other->name . "', the method is only an attribute";
418 # before/after/around methods are a little trickier
419 # since we wrap the original local method (if applicable)
420 # so we need to check if the original wrapped method is
421 # from the same package, and not a wrap of the super method
422 if ($method->isa('Class::MOP::Method::Wrapped') ||
423 $method->isa('Moose::Meta::Method::Overriden')) {
424 ($other->name->isa($method->get_original_method->package_name))
425 || confess "'" . $self->name . "' requires the method '$required_method_name' " .
426 "to be implemented by '" . $other->name . "', the method is only a method modifier";
432 sub _apply_attributes {
433 my ($self, $other) = @_;
434 foreach my $attribute_name ($self->get_attribute_list) {
435 # it if it has one already
436 if ($other->has_attribute($attribute_name) &&
437 # make sure we haven't seen this one already too
438 $other->get_attribute($attribute_name) != $self->get_attribute($attribute_name)) {
439 # see if we are being composed
441 if ($other->isa('Moose::Meta::Role')) {
442 # all attribute conflicts between roles
443 # result in an immediate fatal error
444 confess "Role '" . $self->name . "' has encountered an attribute conflict " .
445 "during composition. This is fatal error and cannot be disambiguated.";
448 # but if this is a class, we
449 # can safely skip adding the
450 # attribute to the class
456 # this is kinda ugly ...
457 if ($other->isa('Moose::Meta::Class')) {
458 $other->_process_attribute(
460 %{$self->get_attribute($attribute_name)}
464 $other->add_attribute(
466 $self->get_attribute($attribute_name)
474 my ($self, $other) = @_;
475 foreach my $method_name ($self->get_method_list) {
476 # it if it has one already
477 if ($other->has_method($method_name) &&
478 # and if they are not the same thing ...
479 $other->get_method($method_name)->body != $self->get_method($method_name)->body) {
480 # see if we are composing into a role
481 if ($other->isa('Moose::Meta::Role')) {
482 # method conflicts between roles result
483 # in the method becoming a requirement
484 $other->add_required_methods($method_name);
486 # we have to remove the method from our
487 # role, if this is being called from combine()
488 # which means the meta is an anon class
489 # this *may* cause problems later, but it
490 # is probably fairly safe to assume that
491 # anon classes will only be used internally
492 # or by people who know what they are doing
493 $other->Moose::Meta::Class::remove_method($method_name)
494 if $other->name =~ /__COMPOSITE_ROLE_SANDBOX__/;
501 # add it, although it could be overriden
502 $other->alias_method(
504 $self->get_method($method_name)
510 sub _apply_override_method_modifiers {
511 my ($self, $other) = @_;
512 foreach my $method_name ($self->get_method_modifier_list('override')) {
513 # it if it has one already then ...
514 if ($other->has_method($method_name)) {
515 # if it is being composed into another role
516 # we have a conflict here, because you cannot
517 # combine an overriden method with a locally
519 if ($other->isa('Moose::Meta::Role')) {
520 confess "Role '" . $self->name . "' has encountered an 'override' method conflict " .
521 "during composition (A local method of the same name as been found). This " .
525 # if it is a class, then we
526 # just ignore this here ...
531 # if no local method is found, then we
532 # must check if we are a role or class
533 if ($other->isa('Moose::Meta::Role')) {
534 # if we are a role, we need to make sure
535 # we dont have a conflict with the role
536 # we are composing into
537 if ($other->has_override_method_modifier($method_name) &&
538 $other->get_override_method_modifier($method_name) != $self->get_override_method_modifier($method_name)) {
539 confess "Role '" . $self->name . "' has encountered an 'override' method conflict " .
540 "during composition (Two 'override' methods of the same name encountered). " .
541 "This is fatal error.";
544 # if there is no conflict,
545 # just add it to the role
546 $other->add_override_method_modifier(
548 $self->get_override_method_modifier($method_name)
553 # if this is not a role, then we need to
554 # find the original package of the method
555 # so that we can tell the class were to
556 # find the right super() method
557 my $method = $self->get_override_method_modifier($method_name);
558 my $package = svref_2object($method)->GV->STASH->NAME;
559 # if it is a class, we just add it
560 $other->add_override_method_modifier($method_name, $method, $package);
566 sub _apply_method_modifiers {
567 my ($self, $modifier_type, $other) = @_;
568 my $add = "add_${modifier_type}_method_modifier";
569 my $get = "get_${modifier_type}_method_modifiers";
570 foreach my $method_name ($self->get_method_modifier_list($modifier_type)) {
574 ) foreach $self->$get($method_name);
578 sub _apply_before_method_modifiers { (shift)->_apply_method_modifiers('before' => @_) }
579 sub _apply_around_method_modifiers { (shift)->_apply_method_modifiers('around' => @_) }
580 sub _apply_after_method_modifiers { (shift)->_apply_method_modifiers('after' => @_) }
590 Moose::Meta::Role - The Moose Role metaclass
594 Please see L<Moose::Role> for more information about roles.
595 For the most part, this has no user-serviceable parts inside
596 this module. It's API is still subject to some change (although
597 probably not that much really).
635 =item B<add_excluded_roles>
637 =item B<excludes_role>
639 =item B<get_excluded_roles_list>
641 =item B<get_excluded_roles_map>
643 =item B<calculate_all_roles>
649 =item B<method_metaclass>
651 =item B<find_method_by_name>
657 =item B<alias_method>
659 =item B<get_method_list>
661 =item B<get_method_map>
667 =item B<add_attribute>
669 =item B<has_attribute>
671 =item B<get_attribute>
673 =item B<get_attribute_list>
675 =item B<get_attribute_map>
677 =item B<remove_attribute>
683 =item B<add_required_methods>
685 =item B<remove_required_methods>
687 =item B<get_required_method_list>
689 =item B<get_required_methods_map>
691 =item B<requires_method>
697 =item B<add_after_method_modifier>
699 =item B<add_around_method_modifier>
701 =item B<add_before_method_modifier>
703 =item B<add_override_method_modifier>
709 =item B<has_after_method_modifiers>
711 =item B<has_around_method_modifiers>
713 =item B<has_before_method_modifiers>
715 =item B<has_override_method_modifier>
721 =item B<get_after_method_modifiers>
723 =item B<get_around_method_modifiers>
725 =item B<get_before_method_modifiers>
727 =item B<get_method_modifier_list>
733 =item B<get_override_method_modifier>
735 =item B<get_after_method_modifiers_map>
737 =item B<get_around_method_modifiers_map>
739 =item B<get_before_method_modifiers_map>
741 =item B<get_override_method_modifiers_map>
747 All complex software has bugs lurking in it, and this module is no
748 exception. If you find a bug please either email me, or add the bug
753 Stevan Little E<lt>stevan@iinteractive.comE<gt>
755 =head1 COPYRIGHT AND LICENSE
757 Copyright 2006, 2007 by Infinity Interactive, Inc.
759 L<http://www.iinteractive.com>
761 This library is free software; you can redistribute it and/or modify
762 it under the same terms as Perl itself.