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[gitmo/Moose.git] / lib / Moose / Meta / Role / Application / ToClass.pm

package Moose::Meta::Role::Application::ToClass;

use strict;
use warnings;
use metaclass;

use Carp            'confess';
use Scalar::Util    'blessed';

use Data::Dumper;

our $VERSION   = '0.50';
our $AUTHORITY = 'cpan:STEVAN';

use base 'Moose::Meta::Role::Application';

sub apply {
    my ($self, $role, $class) = @_;    
    $self->SUPER::apply($role, $class);
    $class->add_role($role);        
}

sub check_role_exclusions {
    my ($self, $role, $class) = @_;
    if ($class->excludes_role($role->name)) {
        confess "Conflict detected: " . $class->name . " excludes role '" . $role->name . "'";
    }
    foreach my $excluded_role_name ($role->get_excluded_roles_list) {
        if ($class->does_role($excluded_role_name)) {
            confess "The class " . $class->name . " does the excluded role '$excluded_role_name'";
        }
    }
}

sub check_required_methods {
    my ($self, $role, $class) = @_;
    # NOTE:
    # we might need to move this down below the
    # the attributes so that we can require any
    # attribute accessors. However I am thinking
    # that maybe those are somehow exempt from
    # the require methods stuff.
    foreach my $required_method_name ($role->get_required_method_list) {

        if (!$class->find_method_by_name($required_method_name)) {
            
            next if $self->is_aliased_method($required_method_name);
            
            confess "'" . $role->name . "' requires the method '$required_method_name' " .
                    "to be implemented by '" . $class->name . "'";
        }
        else {
            # NOTE:
            # we need to make sure that the method is
            # not a method modifier, because those do
            # not satisfy the requirements ...
            my $method = $class->find_method_by_name($required_method_name);

            # check if it is a generated accessor ...
            (!$method->isa('Class::MOP::Method::Accessor'))
                || confess "'" . $role->name . "' requires the method '$required_method_name' " .
                           "to be implemented by '" . $class->name . "', the method is only an attribute accessor";

            # NOTE:
            # All other tests here have been removed, they were tests
            # for overriden methods and before/after/around modifiers.
            # But we realized that for classes any overriden or modified
            # methods would be backed by a real method of that name
            # (and therefore meet the requirement). And for roles, the
            # overriden and modified methods are "in statis" and so would
            # not show up in this test anyway (and as a side-effect they
            # would not fufill the requirement, which is exactly what we
            # want them to do anyway).
            # - SL
        }
    }
}

sub check_required_attributes {
    
}

sub apply_attributes {
    my ($self, $role, $class) = @_;
    foreach my $attribute_name ($role->get_attribute_list) {
        # it if it has one already
        if ($class->has_attribute($attribute_name) &&
            # make sure we haven't seen this one already too
            $class->get_attribute($attribute_name) != $role->get_attribute($attribute_name)) {
            next;
        }
        else {
            $class->add_attribute(
                $attribute_name,
                $role->get_attribute($attribute_name)
            );
        }
    }
}

sub apply_methods {
    my ($self, $role, $class) = @_;
    foreach my $method_name ($role->get_method_list) {
        
        next if $self->is_method_excluded($method_name);
        
        # it if it has one already
        if ($class->has_method($method_name) &&
            # and if they are not the same thing ...
            $class->get_method($method_name)->body != $role->get_method($method_name)->body) {
            next;
        }
        else {
            # add it, although it could be overriden
            $class->alias_method(
                $method_name,
                $role->get_method($method_name)
            );         
        }
        
        if ($self->is_method_aliased($method_name)) {
            my $aliased_method_name = $self->get_method_aliases->{$method_name};
            # it if it has one already
            if ($class->has_method($aliased_method_name) &&
                # and if they are not the same thing ...
                $class->get_method($aliased_method_name)->body != $role->get_method($method_name)->body) {
                confess "Cannot create a method alias if a local method of the same name exists";
            }            
            $class->alias_method(
                $aliased_method_name,
                $role->get_method($method_name)
            );                
        }        
    }
    # we must reset the cache here since
    # we are just aliasing methods, otherwise
    # the modifiers go wonky.
    $class->reset_package_cache_flag;        
}

sub apply_override_method_modifiers {
    my ($self, $role, $class) = @_;
    foreach my $method_name ($role->get_method_modifier_list('override')) {
        # it if it has one already then ...
        if ($class->has_method($method_name)) {
            next;
        }
        else {
            # if this is not a role, then we need to
            # find the original package of the method
            # so that we can tell the class were to
            # find the right super() method
            my $method = $role->get_override_method_modifier($method_name);
            my ($package) = Class::MOP::get_code_info($method);
            # if it is a class, we just add it
            $class->add_override_method_modifier($method_name, $method, $package);
        }
    }
}

sub apply_method_modifiers {
    my ($self, $modifier_type, $role, $class) = @_;
    my $add = "add_${modifier_type}_method_modifier";
    my $get = "get_${modifier_type}_method_modifiers";
    foreach my $method_name ($role->get_method_modifier_list($modifier_type)) {
        $class->$add(
            $method_name,
            $_
        ) foreach $role->$get($method_name);
    }
}

1;

__END__

=pod

=head1 NAME

Moose::Meta::Role::Application::ToClass - Compose a role into a class

=head1 DESCRIPTION

=head2 METHODS

=over 4

=item B<new>

=item B<meta>

=item B<apply>

=item B<check_role_exclusions>

=item B<check_required_methods>

=item B<check_required_attributes>

=item B<apply_attributes>

=item B<apply_methods>

=item B<apply_method_modifiers>

=item B<apply_override_method_modifiers>

=back

=head1 BUGS

All complex software has bugs lurking in it, and this module is no
exception. If you find a bug please either email me, or add the bug
to cpan-RT.

=head1 AUTHOR

Stevan Little E<lt>stevan@iinteractive.comE<gt>

=head1 COPYRIGHT AND LICENSE

Copyright 2006-2008 by Infinity Interactive, Inc.

L<http://www.iinteractive.com>

This library is free software; you can redistribute it and/or modify
it under the same terms as Perl itself.

=cut