package Class::MOP::Method::Constructor;
use strict;
use warnings;
use Carp 'confess';
use Scalar::Util 'blessed', 'weaken';
our $VERSION = '1.12';
$VERSION = eval $VERSION;
our $AUTHORITY = 'cpan:STEVAN';
use base 'Class::MOP::Method::Inlined';
sub new {
my $class = shift;
my %options = @_;
(blessed $options{metaclass} && $options{metaclass}->isa('Class::MOP::Class'))
|| confess "You must pass a metaclass instance if you want to inline"
if $options{is_inline};
($options{package_name} && $options{name})
|| confess "You must supply the package_name and name parameters $Class::MOP::Method::UPGRADE_ERROR_TEXT";
my $self = $class->_new(\%options);
# we don't want this creating
# a cycle in the code, if not
# needed
weaken($self->{'associated_metaclass'});
$self->_initialize_body;
return $self;
}
sub _new {
my $class = shift;
return Class::MOP::Class->initialize($class)->new_object(@_)
if $class ne __PACKAGE__;
my $params = @_ == 1 ? $_[0] : {@_};
return bless {
# inherited from Class::MOP::Method
body => $params->{body},
# associated_metaclass => $params->{associated_metaclass}, # overriden
package_name => $params->{package_name},
name => $params->{name},
original_method => $params->{original_method},
# inherited from Class::MOP::Generated
is_inline => $params->{is_inline} || 0,
definition_context => $params->{definition_context},
# inherited from Class::MOP::Inlined
_expected_method_class => $params->{_expected_method_class},
# defined in this subclass
options => $params->{options} || {},
associated_metaclass => $params->{metaclass},
}, $class;
}
## accessors
sub options { (shift)->{'options'} }
sub associated_metaclass { (shift)->{'associated_metaclass'} }
## cached values ...
sub _attributes {
my $self = shift;
$self->{'attributes'} ||= [ $self->associated_metaclass->get_all_attributes ]
}
## method
sub _initialize_body {
my $self = shift;
my $method_name = '_generate_constructor_method';
$method_name .= '_inline' if $self->is_inline;
$self->{'body'} = $self->$method_name;
}
sub _generate_constructor_method {
return sub { Class::MOP::Class->initialize(shift)->new_object(@_) }
}
sub _generate_constructor_method_inline {
my $self = shift;
my $defaults = [map { $_->default } @{ $self->_attributes }];
my $close_over = {
'$defaults' => \$defaults,
};
my $source = 'sub {';
$source .= "\n" . 'my $class = shift;';
$source .= "\n" . 'return Class::MOP::Class->initialize($class)->new_object(@_)';
$source .= "\n" . ' if $class ne \'' . $self->associated_metaclass->name . '\';';
$source .= "\n" . 'my $params = @_ == 1 ? $_[0] : {@_};';
$source .= "\n" . 'my $instance = ' . $self->associated_metaclass->inline_create_instance('$class');
my $idx = 0;
$source .= ";\n" . (join ";\n" => map {
$self->_generate_slot_initializer($_, $idx++)
} @{ $self->_attributes });
if (Class::MOP::metaclass_is_weak($self->associated_metaclass->name)) {
$source .= ";\n" . $self->associated_metaclass->_inline_set_mop_slot('$instance', 'Class::MOP::class_of($class)');
}
$source .= ";\n" . 'return $instance';
$source .= ";\n" . '}';
warn $source if $self->options->{debug};
my ( $code, $e ) = $self->_eval_closure(
$close_over,
$source
);
confess "Could not eval the constructor :\n\n$source\n\nbecause :\n\n$e" if $e;
return $code;
}
sub _generate_slot_initializer {
my $self = shift;
my $attr = shift;
my $idx = shift;
my $default;
if ($attr->has_default) {
$default = $self->_generate_default_value($attr, $idx);
} elsif( $attr->has_builder ) {
$default = '$instance->'.$attr->builder;
}
if ( defined( my $init_arg = $attr->init_arg ) ) {
return (
'if(exists $params->{\''
. $init_arg . '\'}){' . "\n"
. $attr->inline_set(
'$instance',
'$params->{\'' . $init_arg . '\'}'
)
. "\n" . '} '
. (
!defined $default ? '' : 'else {' . "\n"
. $attr->inline_set(
'$instance',
$default
)
. "\n" . '}'
)
);
}
elsif ( defined $default ) {
return (
$attr->inline_set(
'$instance',
$default
)
. "\n"
);
}
else {
return '';
}
}
sub _generate_default_value {
my ($self, $attr, $index) = @_;
# NOTE:
# default values can either be CODE refs
# in which case we need to call them. Or
# they can be scalars (strings/numbers)
# in which case we can just deal with them
# in the code we eval.
if ($attr->is_default_a_coderef) {
return '$defaults->[' . $index . ']->($instance)';
}
else {
return '$defaults->[' . $index . ']';
}
}
1;
__END__
=pod
=head1 NAME
Class::MOP::Method::Constructor - Method Meta Object for constructors
=head1 SYNOPSIS
use Class::MOP::Method::Constructor;
my $constructor = Class::MOP::Method::Constructor->new(
metaclass => $metaclass,
options => {
debug => 1, # this is all for now
},
);
# calling the constructor ...
$constructor->body->execute($metaclass->name, %params);
=head1 DESCRIPTION
This is a subclass of C<Class::MOP::Method> which generates
constructor methods.
=head1 METHODS
=over 4
=item B<< Class::MOP::Method::Constructor->new(%options) >>
This creates a new constructor object. It accepts a hash reference of
options.
=over 8
=item * metaclass
This should be a L<Class::MOP::Class> object. It is required.
=item * name
The method name (without a package name). This is required.
=item * package_name
The package name for the method. This is required.
=item * is_inline
This indicates whether or not the constructor should be inlined. This
defaults to false.
=back
=item B<< $metamethod->is_inline >>
Returns a boolean indicating whether or not the constructor is
inlined.
=item B<< $metamethod->associated_metaclass >>
This returns the L<Class::MOP::Class> object for the method.
=back
=head1 AUTHORS
Stevan Little E<lt>stevan@iinteractive.comE<gt>
=head1 COPYRIGHT AND LICENSE
Copyright 2006-2010 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