package Mouse::Meta::Role;
-use strict;
-use warnings;
-use Carp 'confess';
+use Mouse::Util qw(:meta not_supported english_list); # enables strict and warnings
-use base qw(Mouse::Meta::Module);
+use Mouse::Meta::Module;
+our @ISA = qw(Mouse::Meta::Module);
-do {
- my %METACLASS_CACHE;
+sub method_metaclass(){ 'Mouse::Meta::Role::Method' } # required for get_method()
- # because Mouse doesn't introspect existing classes, we're forced to
- # only pay attention to other Mouse classes
- sub _metaclass_cache {
- my $class = shift;
- my $name = shift;
- return $METACLASS_CACHE{$name};
- }
-
- sub initialize {
- my($class, $package_name, @args) = @_;
-
- ($package_name && !ref($package_name))\r
- || confess("You must pass a package name and it cannot be blessed");\r
-
- return $METACLASS_CACHE{$package_name}
- ||= $class->_new(package => $package_name, @args);
- }
-};
-
-sub _new {
+sub _construct_meta {
my $class = shift;
+
my %args = @_;
$args{methods} ||= {};
$args{required_methods} ||= [];
$args{roles} ||= [];
- bless \%args, $class;
+ my $self = bless \%args, ref($class) || $class;
+ if($class ne __PACKAGE__){
+ $self->meta->_initialize_object($self, \%args);
+ }
+
+ return $self;
}
-sub add_required_methods {
+sub create_anon_role{
my $self = shift;
- my @methods = @_;
+ return $self->create(undef, @_);
+}
+
+sub is_anon_role{
+ return exists $_[0]->{anon_serial_id};
+}
+
+sub get_roles { $_[0]->{roles} }
+
+sub get_required_method_list{
+ return @{ $_[0]->{required_methods} };
+}
+
+sub add_required_methods {
+ my($self, @methods) = @_;
push @{$self->{required_methods}}, @methods;
}
+sub requires_method {
+ my($self, $name) = @_;
+ return scalar( grep{ $_ eq $name } @{ $self->{required_methods} } ) != 0;
+}
+
sub add_attribute {
my $self = shift;
my $name = shift;
- my $spec = shift;
- $self->{attributes}->{$name} = $spec;
+
+ $self->{attributes}->{$name} = (@_ == 1) ? $_[0] : { @_ };
}
-sub has_attribute { exists $_[0]->{attributes}->{$_[1]} }
-sub get_attribute_list { keys %{ $_[0]->{attributes} } }
-sub get_attribute { $_[0]->{attributes}->{$_[1]} }
+sub _canonicalize_apply_args{
+ my($self, $applicant, %args) = @_;
+
+ if($applicant->isa('Mouse::Meta::Class')){ # Application::ToClass
+ $args{_to} = 'class';
+ }
+ elsif($applicant->isa('Mouse::Meta::Role')){ # Application::ToRole
+ $args{_to} = 'role';
+ }
+ else{ # Appplication::ToInstance
+ $args{_to} = 'class';
+
+ my $metaclass = $applicant->meta->create_anon_class(
+ superclasses => [ref $applicant],
+ cache => 1,
+ );
+ bless $applicant, $metaclass->name; # rebless
+
+ $applicant = $metaclass;
+ }
+
+ if($args{alias} && !exists $args{-alias}){
+ $args{-alias} = $args{alias};
+ }
+ if($args{excludes} && !exists $args{-excludes}){
+ $args{-excludes} = $args{excludes};
+ }
+
+ if(my $excludes = $args{-excludes}){
+ $args{-excludes} = {}; # replace with a hash ref
+ if(ref $excludes){
+ %{$args{-excludes}} = (map{ $_ => undef } @{$excludes});
+ }
+ else{
+ $args{-excludes}{$excludes} = undef;
+ }
+ }
+
+ return( $applicant, \%args );
+}
sub _check_required_methods{
my($role, $class, $args, @other_roles) = @_;
- if($class->isa('Mouse::Meta::Class')){
+ if($args->{_to} eq 'class'){
my $class_name = $class->name;
+ my $role_name = $role->name;
+ my @missing;
foreach my $method_name(@{$role->{required_methods}}){
- unless($class_name->can($method_name)){
- my $role_name = $role->name;
+ if(!$class_name->can($method_name)){
my $has_method = 0;
foreach my $another_role_spec(@other_roles){
last;
}
}
-
- confess "'$role_name' requires the method '$method_name' to be implemented by '$class_name'"
- unless $has_method;
+
+ push @missing, $method_name if !$has_method;
}
}
+ if(@missing){
+ $class->throw_error("'$role_name' requires the "
+ . (@missing == 1 ? 'method' : 'methods')
+ . " "
+ . english_list(map{ sprintf q{'%s'}, $_ } @missing)
+ . " to be implemented by '$class_name'");
+ }
+ }
+ else {
+ # apply role($role) to role($class)
+ foreach my $method_name($role->get_required_method_list){
+ next if $class->has_method($method_name); # already has it
+ $class->add_required_methods($method_name);
+ }
}
return;
my $role_name = $role->name;
my $class_name = $class->name;
- my $alias = $args->{alias};
+
+ my $alias = $args->{-alias};
+ my $excludes = $args->{-excludes};
foreach my $method_name($role->get_method_list){
next if $method_name eq 'meta';
my $code = $role_name->can($method_name);
- if(do{ no strict 'refs'; defined &{$class_name . '::' . $method_name} }){
- # XXX what's Moose's behavior?
- }
- else{
- $class->add_method($method_name => $code);
+
+ if(!exists $excludes->{$method_name}){
+ if(!$class->has_method($method_name)){
+ $class->add_method($method_name => $code);
+ }
}
if($alias && $alias->{$method_name}){
my $dstname = $alias->{$method_name};
- if(do{ no strict 'refs'; defined &{$class_name . '::' . $dstname} }){
- # XXX wat's Moose's behavior?
+
+ my $dstcode = do{ no strict 'refs'; *{$class_name . '::' . $dstname}{CODE} };
+
+ if(defined($dstcode) && $dstcode != $code){
+ $class->throw_error("Cannot create a method alias if a local method of the same name exists");
}
else{
$class->add_method($dstname => $code);
sub _apply_attributes{
my($role, $class, $args) = @_;
- if ($class->isa('Mouse::Meta::Class')) {
+ if ($args->{_to} eq 'class') {
# apply role to class
for my $attr_name ($role->get_attribute_list) {
next if $class->has_attribute($attr_name);
my $spec = $role->get_attribute($attr_name);
- my $attr_metaclass = 'Mouse::Meta::Attribute';
- if ( my $metaclass_name = $spec->{metaclass} ) {
- $attr_metaclass = Mouse::Util::resolve_metaclass_alias(
- 'Attribute',
- $metaclass_name
- );
- }
-
- $attr_metaclass->create($class, $attr_name => %$spec);
+ $class->add_attribute($attr_name => %{$spec});
}
- } else {
+ }
+ else {
# apply role to role
for my $attr_name ($role->get_attribute_list) {
next if $class->has_attribute($attr_name);
sub _apply_modifiers{
my($role, $class, $args) = @_;
- for my $modifier_type (qw/before after around override/) {
+ for my $modifier_type (qw/override before around after/) {
my $add_modifier = "add_${modifier_type}_method_modifier";
my $modifiers = $role->{"${modifier_type}_method_modifiers"};
while(my($method_name, $modifier_codes) = each %{$modifiers}){
- foreach my $code(@{$modifier_codes}){
+ foreach my $code(ref($modifier_codes) eq 'ARRAY' ? @{$modifier_codes} : $modifier_codes){
$class->$add_modifier($method_name => $code);
}
}
sub _append_roles{
my($role, $class, $args) = @_;
- my $roles = $class->isa('Mouse::Meta::Class') ? $class->roles : $class->get_roles;
+ my $roles = ($args->{_to} eq 'class') ? $class->roles : $class->get_roles;
foreach my $r($role, @{$role->get_roles}){
if(!$class->does_role($r->name)){
# Moose uses Application::ToInstance, Application::ToClass, Application::ToRole
sub apply {
- my($self, $class, %args) = @_;
+ my $self = shift;
+ my $applicant = shift;
+ my $args;
- if ($class->isa('Mouse::Object')) {
- Carp::croak('Mouse does not support Application::ToInstance yet');
- }
+ ($applicant, $args) = $self->_canonicalize_apply_args($applicant, @_);
- $self->_check_required_methods($class, \%args);
- $self->_apply_methods($class, \%args);
- $self->_apply_attributes($class, \%args);
- $self->_apply_modifiers($class, \%args);
- $self->_append_roles($class, \%args);
+ $self->_check_required_methods($applicant, $args);
+ $self->_apply_methods($applicant, $args);
+ $self->_apply_attributes($applicant, $args);
+ $self->_apply_modifiers($applicant, $args);
+ $self->_append_roles($applicant, $args);
return;
}
sub combine_apply {
- my(undef, $class, @roles) = @_;
+ my($role_class, $applicant, @roles) = @_;
+
+ ($applicant) = $role_class->_canonicalize_apply_args($applicant);
+
+ # check conflicting
+ my %method_provided;
+ my @method_conflicts;
+ my %attr_provided;
+ my %override_provided;
+
+ foreach my $role_spec (@roles) {
+ my $role = $role_spec->[0]->meta;
+ my $role_name = $role->name;
+
+ # methods
+ foreach my $method_name($role->get_method_list){
+ next if $applicant->has_method($method_name); # manually resolved
+
+ my $code = do{ no strict 'refs'; \&{ $role_name . '::' . $method_name } };
+
+ my $c = $method_provided{$method_name};
+
+ if($c && $c->[0] != $code){
+ push @{$c}, $role;
+ push @method_conflicts, $c;
+ }
+ else{
+ $method_provided{$method_name} = [$code, $method_name, $role];
+ }
+ }
+
+ # attributes
+ foreach my $attr_name($role->get_attribute_list){
+ my $attr = $role->get_attribute($attr_name);
+ my $c = $attr_provided{$attr_name};
+ if($c && $c != $attr){
+ $role_class->throw_error("We have encountered an attribute conflict with '$attr_name' "
+ . "during composition. This is fatal error and cannot be disambiguated.")
+ }
+ else{
+ $attr_provided{$attr_name} = $attr;
+ }
+ }
+
+ # override modifiers
+ foreach my $method_name($role->get_method_modifier_list('override')){
+ my $override = $role->get_override_method_modifier($method_name);
+ my $c = $override_provided{$method_name};
+ if($c && $c != $override){
+ $role_class->throw_error( "We have encountered an 'override' method conflict with '$method_name' during "
+ . "composition (Two 'override' methods of the same name encountered). "
+ . "This is fatal error.")
+ }
+ else{
+ $override_provided{$method_name} = $override;
+ }
+ }
+ }
+ if(@method_conflicts){
+ my $error;
+
+ if(@method_conflicts == 1){
+ my($code, $method_name, @roles) = @{$method_conflicts[0]};
+ $role_class->throw_error(
+ sprintf q{Due to a method name conflict in roles %s, the method '%s' must be implemented or excluded by '%s'},
+ english_list(map{ sprintf q{'%s'}, $_->name } @roles), $method_name, $applicant->name
+ );
+ }
+ else{
+ @method_conflicts = sort { $a->[0] cmp $b->[0] } @method_conflicts; # to avoid hash-ordering bugs
+ my $methods = english_list(map{ sprintf q{'%s'}, $_->[1] } @method_conflicts);
+ my $roles = english_list(
+ map{ sprintf q{'%s'}, $_->name }
+ map{ my($code, $method_name, @roles) = @{$_}; @roles } @method_conflicts
+ );
+
+ $role_class->throw_error(
+ sprintf q{Due to method name conflicts in roles %s, the methods %s must be implemented or excluded by '%s'},
+ $roles, $methods, $applicant->name
+ );
+ }
+ }
foreach my $role_spec (@roles) {
my($role_name, $args) = @{$role_spec};
my $role = $role_name->meta;
- $role->_check_required_methods($class, $args, @roles);
- $role->_apply_methods($class, $args);
- $role->_apply_attributes($class, $args);
- $role->_apply_modifiers($class, $args);
- $role->_append_roles($class, $args);
+ ($applicant, $args) = $role->_canonicalize_apply_args($applicant, %{$args});
+
+ $role->_check_required_methods($applicant, $args, @roles);
+ $role->_apply_methods($applicant, $args);
+ $role->_apply_attributes($applicant, $args);
+ $role->_apply_modifiers($applicant, $args);
+ $role->_append_roles($applicant, $args);
}
return;
}
-for my $modifier_type (qw/before after around override/) {
+for my $modifier_type (qw/before after around/) {
my $modifier = "${modifier_type}_method_modifiers";
my $add_method_modifier = sub {
push @{ $self->{$modifier}->{$method_name} ||= [] }, $method;
return;
};
+ my $has_method_modifiers = sub{
+ my($self, $method_name) = @_;
+ my $m = $self->{$modifier}->{$method_name};
+ return $m && @{$m} != 0;
+ };
my $get_method_modifiers = sub {
my ($self, $method_name) = @_;
return @{ $self->{$modifier}->{$method_name} ||= [] }
no strict 'refs';
*{ 'add_' . $modifier_type . '_method_modifier' } = $add_method_modifier;
+ *{ 'has_' . $modifier_type . '_method_modifiers' } = $has_method_modifiers;
*{ 'get_' . $modifier_type . '_method_modifiers' } = $get_method_modifiers;
}
-sub get_roles { $_[0]->{roles} }
+sub add_override_method_modifier{
+ my($self, $method_name, $method) = @_;
+
+ if($self->has_method($method_name)){
+ # This error happens in the override keyword or during role composition,
+ # so I added a message, "A local method of ...", only for compatibility (gfx)
+ $self->throw_error("Cannot add an override of method '$method_name' "
+ . "because there is a local version of '$method_name'"
+ . "(A local method of the same name as been found)");
+ }
+
+ $self->{override_method_modifiers}->{$method_name} = $method;
+}
+
+sub has_override_method_modifier {
+ my ($self, $method_name) = @_;
+ return exists $self->{override_method_modifiers}->{$method_name};
+}
+
+sub get_override_method_modifier {
+ my ($self, $method_name) = @_;
+ return $self->{override_method_modifiers}->{$method_name};
+}
+
+sub get_method_modifier_list {
+ my($self, $modifier_type) = @_;
+
+ return keys %{ $self->{$modifier_type . '_method_modifiers'} };
+}
# This is currently not passing all the Moose tests.
sub does_role {
my ($self, $role_name) = @_;
(defined $role_name)
- || confess "You must supply a role name to look for";
+ || $self->throw_error("You must supply a role name to look for");
# if we are it,.. then return true
return 1 if $role_name eq $self->name;
1;
+__END__
+
+=head1 NAME
+
+Mouse::Meta::Role - The Mouse Role metaclass
+
+=head1 SEE ALSO
+
+L<Moose::Meta::Role>
+
+=cut