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 my $self = bless \%args, ref($class) || $class;
22 if($class ne __PACKAGE__){
23 $self->meta->_initialize_object($self, \%args);
31 return $self->create(undef, @_);
35 return exists $_[0]->{anon_serial_id};
38 sub get_roles { $_[0]->{roles} }
40 sub get_required_method_list{
41 return @{ $_[0]->{required_methods} };
44 sub add_required_methods {
45 my($self, @methods) = @_;
46 push @{$self->{required_methods}}, @methods;
50 my($self, $name) = @_;
51 return scalar( grep{ $_ eq $name } @{ $self->{required_methods} } ) != 0;
58 $self->{attributes}->{$name} = (@_ == 1) ? $_[0] : { @_ };
61 sub _canonicalize_apply_args{
62 my($self, $applicant, %args) = @_;
64 if($applicant->isa('Mouse::Meta::Class')){
67 elsif($applicant->isa('Mouse::Meta::Role')){
71 $args{_to} = 'instance';
73 not_supported 'Application::ToInstance';
76 if($args{alias} && !exists $args{-alias}){
77 $args{-alias} = $args{alias};
79 if($args{excludes} && !exists $args{-excludes}){
80 $args{-excludes} = $args{excludes};
83 if(my $excludes = $args{-excludes}){
84 $args{-excludes} = {}; # replace with a hash ref
86 %{$args{-excludes}} = (map{ $_ => undef } @{$excludes});
89 $args{-excludes}{$excludes} = undef;
96 sub _check_required_methods{
97 my($role, $class, $args, @other_roles) = @_;
99 if($args->{_to} eq 'class'){
100 my $class_name = $class->name;
101 my $role_name = $role->name;
103 foreach my $method_name(@{$role->{required_methods}}){
104 if(!$class_name->can($method_name)){
107 foreach my $another_role_spec(@other_roles){
108 my $another_role_name = $another_role_spec->[0];
109 if($role_name ne $another_role_name && $another_role_name->can($method_name)){
115 push @missing, $method_name if !$has_method;
119 $class->throw_error("'$role_name' requires the "
120 . (@missing == 1 ? 'method' : 'methods')
122 . english_list(map{ sprintf q{'%s'}, $_ } @missing)
123 . " to be implemented by '$class_name'");
126 elsif($args->{_to} eq 'role'){
127 # apply role($role) to role($class)
128 foreach my $method_name($role->get_required_method_list){
129 next if $class->has_method($method_name); # already has it
130 $class->add_required_methods($method_name);
138 my($role, $class, $args) = @_;
140 my $role_name = $role->name;
141 my $class_name = $class->name;
143 my $alias = $args->{-alias};
144 my $excludes = $args->{-excludes};
146 foreach my $method_name($role->get_method_list){
147 next if $method_name eq 'meta';
149 my $code = $role_name->can($method_name);
151 if(!exists $excludes->{$method_name}){
152 if(!$class->has_method($method_name)){
153 $class->add_method($method_name => $code);
157 if($alias && $alias->{$method_name}){
158 my $dstname = $alias->{$method_name};
160 my $dstcode = do{ no strict 'refs'; *{$class_name . '::' . $dstname}{CODE} };
162 if(defined($dstcode) && $dstcode != $code){
163 $class->throw_error("Cannot create a method alias if a local method of the same name exists");
166 $class->add_method($dstname => $code);
174 sub _apply_attributes{
175 my($role, $class, $args) = @_;
177 if ($args->{_to} eq 'class') {
178 # apply role to class
179 for my $attr_name ($role->get_attribute_list) {
180 next if $class->has_attribute($attr_name);
182 my $spec = $role->get_attribute($attr_name);
184 $class->add_attribute($attr_name => %{$spec});
187 elsif($args->{_to} eq 'role'){
189 for my $attr_name ($role->get_attribute_list) {
190 next if $class->has_attribute($attr_name);
192 my $spec = $role->get_attribute($attr_name);
193 $class->add_attribute($attr_name => $spec);
200 sub _apply_modifiers{
201 my($role, $class, $args) = @_;
203 for my $modifier_type (qw/override before around after/) {
204 my $add_modifier = "add_${modifier_type}_method_modifier";
205 my $modifiers = $role->{"${modifier_type}_method_modifiers"};
207 while(my($method_name, $modifier_codes) = each %{$modifiers}){
208 foreach my $code(ref($modifier_codes) eq 'ARRAY' ? @{$modifier_codes} : $modifier_codes){
209 $class->$add_modifier($method_name => $code);
217 my($role, $class, $args) = @_;
219 my $roles = ($args->{_to} eq 'class') ? $class->roles : $class->get_roles;
221 foreach my $r($role, @{$role->get_roles}){
222 if(!$class->does_role($r->name)){
229 # Moose uses Application::ToInstance, Application::ToClass, Application::ToRole
232 my $applicant = shift;
234 my $args = $self->_canonicalize_apply_args($applicant, @_);
236 $self->_check_required_methods($applicant, $args);
237 $self->_apply_methods($applicant, $args);
238 $self->_apply_attributes($applicant, $args);
239 $self->_apply_modifiers($applicant, $args);
240 $self->_append_roles($applicant, $args);
245 my(undef, $class, @roles) = @_;
247 if($class->isa('Mouse::Object')){
248 not_supported 'Application::ToInstance';
253 my @method_conflicts;
255 my %override_provided;
257 foreach my $role_spec (@roles) {
258 my $role = $role_spec->[0]->meta;
259 my $role_name = $role->name;
262 foreach my $method_name($role->get_method_list){
263 next if $class->has_method($method_name); # manually resolved
265 my $code = do{ no strict 'refs'; \&{ $role_name . '::' . $method_name } };
267 my $c = $method_provided{$method_name};
269 if($c && $c->[0] != $code){
271 push @method_conflicts, $c;
274 $method_provided{$method_name} = [$code, $method_name, $role];
279 foreach my $attr_name($role->get_attribute_list){
280 my $attr = $role->get_attribute($attr_name);
281 my $c = $attr_provided{$attr_name};
282 if($c && $c != $attr){
283 $class->throw_error("We have encountered an attribute conflict with '$attr_name' "
284 . "during composition. This is fatal error and cannot be disambiguated.")
287 $attr_provided{$attr_name} = $attr;
292 foreach my $method_name($role->get_method_modifier_list('override')){
293 my $override = $role->get_override_method_modifier($method_name);
294 my $c = $override_provided{$method_name};
295 if($c && $c != $override){
296 $class->throw_error( "We have encountered an 'override' method conflict with '$method_name' during "
297 . "composition (Two 'override' methods of the same name encountered). "
298 . "This is fatal error.")
301 $override_provided{$method_name} = $override;
305 if(@method_conflicts){
308 if(@method_conflicts == 1){
309 my($code, $method_name, @roles) = @{$method_conflicts[0]};
311 sprintf q{Due to a method name conflict in roles %s, the method '%s' must be implemented or excluded by '%s'},
312 english_list(map{ sprintf q{'%s'}, $_->name } @roles), $method_name, $class->name
316 @method_conflicts = sort { $a->[0] cmp $b->[0] } @method_conflicts; # to avoid hash-ordering bugs
317 my $methods = english_list(map{ sprintf q{'%s'}, $_->[1] } @method_conflicts);
318 my $roles = english_list(
319 map{ sprintf q{'%s'}, $_->name }
320 map{ my($code, $method_name, @roles) = @{$_}; @roles } @method_conflicts
324 sprintf q{Due to method name conflicts in roles %s, the methods %s must be implemented or excluded by '%s'},
325 $roles, $methods, $class->name
330 foreach my $role_spec (@roles) {
331 my($role_name, $args) = @{$role_spec};
333 my $role = $role_name->meta;
335 $args = $role->_canonicalize_apply_args($class, %{$args});
337 $role->_check_required_methods($class, $args, @roles);
338 $role->_apply_methods($class, $args);
339 $role->_apply_attributes($class, $args);
340 $role->_apply_modifiers($class, $args);
341 $role->_append_roles($class, $args);
346 for my $modifier_type (qw/before after around/) {
348 my $modifier = "${modifier_type}_method_modifiers";
349 my $add_method_modifier = sub {
350 my ($self, $method_name, $method) = @_;
352 push @{ $self->{$modifier}->{$method_name} ||= [] }, $method;
355 my $has_method_modifiers = sub{
356 my($self, $method_name) = @_;
357 my $m = $self->{$modifier}->{$method_name};
358 return $m && @{$m} != 0;
360 my $get_method_modifiers = sub {
361 my ($self, $method_name) = @_;
362 return @{ $self->{$modifier}->{$method_name} ||= [] }
366 *{ 'add_' . $modifier_type . '_method_modifier' } = $add_method_modifier;
367 *{ 'has_' . $modifier_type . '_method_modifiers' } = $has_method_modifiers;
368 *{ 'get_' . $modifier_type . '_method_modifiers' } = $get_method_modifiers;
371 sub add_override_method_modifier{
372 my($self, $method_name, $method) = @_;
374 if($self->has_method($method_name)){
375 # This error happens in the override keyword or during role composition,
376 # so I added a message, "A local method of ...", only for compatibility (gfx)
377 $self->throw_error("Cannot add an override of method '$method_name' "
378 . "because there is a local version of '$method_name'"
379 . "(A local method of the same name as been found)");
382 $self->{override_method_modifiers}->{$method_name} = $method;
385 sub has_override_method_modifier {
386 my ($self, $method_name) = @_;
387 return exists $self->{override_method_modifiers}->{$method_name};
390 sub get_override_method_modifier {
391 my ($self, $method_name) = @_;
392 return $self->{override_method_modifiers}->{$method_name};
395 sub get_method_modifier_list {
396 my($self, $modifier_type) = @_;
398 return keys %{ $self->{$modifier_type . '_method_modifiers'} };
401 # This is currently not passing all the Moose tests.
403 my ($self, $role_name) = @_;
406 || $self->throw_error("You must supply a role name to look for");
408 # if we are it,.. then return true
409 return 1 if $role_name eq $self->name;
410 # otherwise.. check our children
411 for my $role (@{ $self->get_roles }) {
412 return 1 if $role->does_role($role_name);
424 Mouse::Meta::Role - The Mouse Role metaclass