1 package Mouse::Meta::Role;
5 use Mouse::Util qw(:meta not_supported english_list get_code_info);
6 use Mouse::Meta::Module;
7 our @ISA = qw(Mouse::Meta::Module);
9 sub method_metaclass(){ 'Mouse::Meta::Role::Method' } # required for get_method()
16 $args{methods} ||= {};
17 $args{attributes} ||= {};
18 $args{required_methods} ||= [];
21 # return Mouse::Meta::Class->initialize($class)->new_object(%args)
22 # if $class ne __PACKAGE__;
24 return bless \%args, ref($class) || $class;
29 return $self->create(undef, @_);
33 return exists $_[0]->{anon_serial_id};
36 sub get_roles { $_[0]->{roles} }
38 sub get_required_method_list{
39 return @{ $_[0]->{required_methods} };
42 sub add_required_methods {
43 my($self, @methods) = @_;
44 push @{$self->{required_methods}}, @methods;
48 my($self, $name) = @_;
49 return scalar( grep{ $_ eq $name } @{ $self->{required_methods} } ) != 0;
56 $self->{attributes}->{$name} = (@_ == 1) ? $_[0] : { @_ };
59 sub _canonicalize_apply_args{
60 my($self, $applicant, %args) = @_;
62 if($applicant->isa('Mouse::Meta::Class')){
65 elsif($applicant->isa('Mouse::Meta::Role')){
69 $args{_to} = 'instance';
71 not_supported 'Application::ToInstance';
74 if($args{alias} && !exists $args{-alias}){
75 $args{-alias} = $args{alias};
77 if($args{excludes} && !exists $args{-excludes}){
78 $args{-excludes} = $args{excludes};
81 if(my $excludes = $args{-excludes}){
82 $args{-excludes} = {}; # replace with a hash ref
84 %{$args{-excludes}} = (map{ $_ => undef } @{$excludes});
87 $args{-excludes}{$excludes} = undef;
94 sub _check_required_methods{
95 my($role, $class, $args, @other_roles) = @_;
97 if($args->{_to} eq 'class'){
98 my $class_name = $class->name;
99 my $role_name = $role->name;
101 foreach my $method_name(@{$role->{required_methods}}){
102 if(!$class_name->can($method_name)){
105 foreach my $another_role_spec(@other_roles){
106 my $another_role_name = $another_role_spec->[0];
107 if($role_name ne $another_role_name && $another_role_name->can($method_name)){
113 push @missing, $method_name if !$has_method;
117 $class->throw_error("'$role_name' requires the "
118 . (@missing == 1 ? 'method' : 'methods')
120 . english_list(map{ sprintf q{'%s'}, $_ } @missing)
121 . " to be implemented by '$class_name'");
124 elsif($args->{_to} eq 'role'){
125 # apply role($role) to role($class)
126 foreach my $method_name($role->get_required_method_list){
127 next if $class->has_method($method_name); # already has it
128 $class->add_required_methods($method_name);
136 my($role, $class, $args) = @_;
138 my $role_name = $role->name;
139 my $class_name = $class->name;
141 my $alias = $args->{-alias};
142 my $excludes = $args->{-excludes};
144 foreach my $method_name($role->get_method_list){
145 next if $method_name eq 'meta';
147 my $code = $role_name->can($method_name);
149 if(!exists $excludes->{$method_name}){
150 if(!$class->has_method($method_name)){
151 $class->add_method($method_name => $code);
155 if($alias && $alias->{$method_name}){
156 my $dstname = $alias->{$method_name};
158 my $dstcode = do{ no strict 'refs'; *{$class_name . '::' . $dstname}{CODE} };
160 if(defined($dstcode) && $dstcode != $code){
161 $class->throw_error("Cannot create a method alias if a local method of the same name exists");
164 $class->add_method($dstname => $code);
172 sub _apply_attributes{
173 my($role, $class, $args) = @_;
175 if ($args->{_to} eq 'class') {
176 # apply role to class
177 for my $attr_name ($role->get_attribute_list) {
178 next if $class->has_attribute($attr_name);
180 my $spec = $role->get_attribute($attr_name);
182 $class->add_attribute($attr_name => %{$spec});
185 elsif($args->{_to} eq 'role'){
187 for my $attr_name ($role->get_attribute_list) {
188 next if $class->has_attribute($attr_name);
190 my $spec = $role->get_attribute($attr_name);
191 $class->add_attribute($attr_name => $spec);
198 sub _apply_modifiers{
199 my($role, $class, $args) = @_;
201 for my $modifier_type (qw/override before around after/) {
202 my $add_modifier = "add_${modifier_type}_method_modifier";
203 my $modifiers = $role->{"${modifier_type}_method_modifiers"};
205 while(my($method_name, $modifier_codes) = each %{$modifiers}){
206 foreach my $code(ref($modifier_codes) eq 'ARRAY' ? @{$modifier_codes} : $modifier_codes){
207 $class->$add_modifier($method_name => $code);
215 my($role, $class, $args) = @_;
217 my $roles = ($args->{_to} eq 'class') ? $class->roles : $class->get_roles;
219 foreach my $r($role, @{$role->get_roles}){
220 if(!$class->does_role($r->name)){
227 # Moose uses Application::ToInstance, Application::ToClass, Application::ToRole
230 my $applicant = shift;
232 my $args = $self->_canonicalize_apply_args($applicant, @_);
234 $self->_check_required_methods($applicant, $args);
235 $self->_apply_methods($applicant, $args);
236 $self->_apply_attributes($applicant, $args);
237 $self->_apply_modifiers($applicant, $args);
238 $self->_append_roles($applicant, $args);
243 my(undef, $class, @roles) = @_;
245 if($class->isa('Mouse::Object')){
246 not_supported 'Application::ToInstance';
251 my @method_conflicts;
253 my %override_provided;
255 foreach my $role_spec (@roles) {
256 my $role = $role_spec->[0]->meta;
257 my $role_name = $role->name;
260 foreach my $method_name($role->get_method_list){
261 next if $class->has_method($method_name); # manually resolved
263 my $code = do{ no strict 'refs'; \&{ $role_name . '::' . $method_name } };
265 my $c = $method_provided{$method_name};
267 if($c && $c->[0] != $code){
269 push @method_conflicts, $c;
272 $method_provided{$method_name} = [$code, $method_name, $role];
277 foreach my $attr_name($role->get_attribute_list){
278 my $attr = $role->get_attribute($attr_name);
279 my $c = $attr_provided{$attr_name};
280 if($c && $c != $attr){
281 $class->throw_error("We have encountered an attribute conflict with '$attr_name' "
282 . "during composition. This is fatal error and cannot be disambiguated.")
285 $attr_provided{$attr_name} = $attr;
290 foreach my $method_name($role->get_method_modifier_list('override')){
291 my $override = $role->get_override_method_modifier($method_name);
292 my $c = $override_provided{$method_name};
293 if($c && $c != $override){
294 $class->throw_error( "We have encountered an 'override' method conflict with '$method_name' during "
295 . "composition (Two 'override' methods of the same name encountered). "
296 . "This is fatal error.")
299 $override_provided{$method_name} = $override;
303 if(@method_conflicts){
306 if(@method_conflicts == 1){
307 my($code, $method_name, @roles) = @{$method_conflicts[0]};
309 sprintf q{Due to a method name conflict in roles %s, the method '%s' must be implemented or excluded by '%s'},
310 english_list(map{ sprintf q{'%s'}, $_->name } @roles), $method_name, $class->name
314 @method_conflicts = sort { $a->[0] cmp $b->[0] } @method_conflicts; # to avoid hash-ordering bugs
315 my $methods = english_list(map{ sprintf q{'%s'}, $_->[1] } @method_conflicts);
316 my $roles = english_list(
317 map{ sprintf q{'%s'}, $_->name }
318 map{ my($code, $method_name, @roles) = @{$_}; @roles } @method_conflicts
322 sprintf q{Due to method name conflicts in roles %s, the methods %s must be implemented or excluded by '%s'},
323 $roles, $methods, $class->name
328 foreach my $role_spec (@roles) {
329 my($role_name, $args) = @{$role_spec};
331 my $role = $role_name->meta;
333 $args = $role->_canonicalize_apply_args($class, %{$args});
335 $role->_check_required_methods($class, $args, @roles);
336 $role->_apply_methods($class, $args);
337 $role->_apply_attributes($class, $args);
338 $role->_apply_modifiers($class, $args);
339 $role->_append_roles($class, $args);
344 for my $modifier_type (qw/before after around/) {
346 my $modifier = "${modifier_type}_method_modifiers";
347 my $add_method_modifier = sub {
348 my ($self, $method_name, $method) = @_;
350 push @{ $self->{$modifier}->{$method_name} ||= [] }, $method;
353 my $has_method_modifiers = sub{
354 my($self, $method_name) = @_;
355 my $m = $self->{$modifier}->{$method_name};
356 return $m && @{$m} != 0;
358 my $get_method_modifiers = sub {
359 my ($self, $method_name) = @_;
360 return @{ $self->{$modifier}->{$method_name} ||= [] }
364 *{ 'add_' . $modifier_type . '_method_modifier' } = $add_method_modifier;
365 *{ 'has_' . $modifier_type . '_method_modifiers' } = $has_method_modifiers;
366 *{ 'get_' . $modifier_type . '_method_modifiers' } = $get_method_modifiers;
369 sub add_override_method_modifier{
370 my($self, $method_name, $method) = @_;
372 if($self->has_method($method_name)){
373 # This error happens in the override keyword or during role composition,
374 # so I added a message, "A local method of ...", only for compatibility (gfx)
375 $self->throw_error("Cannot add an override of method '$method_name' "
376 . "because there is a local version of '$method_name'"
377 . "(A local method of the same name as been found)");
380 $self->{override_method_modifiers}->{$method_name} = $method;
383 sub has_override_method_modifier {
384 my ($self, $method_name) = @_;
385 return exists $self->{override_method_modifiers}->{$method_name};
388 sub get_override_method_modifier {
389 my ($self, $method_name) = @_;
390 return $self->{override_method_modifiers}->{$method_name};
393 sub get_method_modifier_list {
394 my($self, $modifier_type) = @_;
396 return keys %{ $self->{$modifier_type . '_method_modifiers'} };
399 # This is currently not passing all the Moose tests.
401 my ($self, $role_name) = @_;
404 || $self->throw_error("You must supply a role name to look for");
406 # if we are it,.. then return true
407 return 1 if $role_name eq $self->name;
408 # otherwise.. check our children
409 for my $role (@{ $self->get_roles }) {
410 return 1 if $role->does_role($role_name);
422 Mouse::Meta::Role - The Mouse Role metaclass