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package Moose::Meta::Method::Delegation;
use strict;
use warnings;
use Carp 'confess';
use Scalar::Util 'blessed', 'weaken';
our $VERSION = '1.09';
$VERSION = eval $VERSION;
our $AUTHORITY = 'cpan:STEVAN';
use base 'Moose::Meta::Method',
'Class::MOP::Method::Generated';
sub new {
my $class = shift;
my %options = @_;
( exists $options{attribute} )
|| confess "You must supply an attribute to construct with";
( blessed( $options{attribute} )
&& $options{attribute}->isa('Moose::Meta::Attribute') )
|| confess
"You must supply an attribute which is a 'Moose::Meta::Attribute' instance";
( $options{package_name} && $options{name} )
|| confess
"You must supply the package_name and name parameters $Class::MOP::Method::UPGRADE_ERROR_TEXT";
( $options{delegate_to_method} && ( !ref $options{delegate_to_method} )
|| ( 'CODE' eq ref $options{delegate_to_method} ) )
|| confess
'You must supply a delegate_to_method which is a method name or a CODE reference';
exists $options{curried_arguments}
|| ( $options{curried_arguments} = [] );
( $options{curried_arguments} &&
( 'ARRAY' eq ref $options{curried_arguments} ) )
|| confess 'You must supply a curried_arguments which is an ARRAY reference';
my $self = $class->_new( \%options );
weaken( $self->{'attribute'} );
$self->_initialize_body;
return $self;
}
sub _new {
my $class = shift;
my $options = @_ == 1 ? $_[0] : {@_};
return bless $options, $class;
}
sub curried_arguments { (shift)->{'curried_arguments'} }
sub associated_attribute { (shift)->{'attribute'} }
sub delegate_to_method { (shift)->{'delegate_to_method'} }
sub _initialize_body {
my $self = shift;
my $method_to_call = $self->delegate_to_method;
return $self->{body} = $method_to_call
if ref $method_to_call;
my $accessor = $self->_get_delegate_accessor;
my $handle_name = $self->name;
# NOTE: we used to do a goto here, but the goto didn't handle
# failure correctly (it just returned nothing), so I took that
# out. However, the more I thought about it, the less I liked it
# doing the goto, and I preferred the act of delegation being
# actually represented in the stack trace. - SL
# not inlining this, since it won't really speed things up at
# all... the only thing that would end up different would be
# interpolating in $method_to_call, and a bunch of things in the
# error handling that mostly never gets called - doy
$self->{body} = sub {
my $instance = shift;
my $proxy = $instance->$accessor();
my $error
= !defined $proxy ? ' is not defined'
: ref($proxy) && !blessed($proxy) ? qq{ is not an object (got '$proxy')}
: undef;
if ($error) {
$self->throw_error(
"Cannot delegate $handle_name to $method_to_call because "
. "the value of "
. $self->associated_attribute->name
. $error,
method_name => $method_to_call,
object => $instance
);
}
unshift @_, @{ $self->curried_arguments };
$proxy->$method_to_call(@_);
};
}
sub _get_delegate_accessor {
my $self = shift;
my $attr = $self->associated_attribute;
# NOTE:
# always use a named method when
# possible, if you use the method
# ref and there are modifiers on
# the accessors then it will not
# pick up the modifiers too. Only
# the named method will assure that
# we also have any modifiers run.
# - SL
my $accessor = $attr->has_read_method
? $attr->get_read_method
: $attr->get_read_method_ref;
$accessor = $accessor->body if Scalar::Util::blessed $accessor;
return $accessor;
}
1;
__END__
=pod
=head1 NAME
Moose::Meta::Method::Delegation - A Moose Method metaclass for delegation methods
=head1 DESCRIPTION
This is a subclass of L<Moose::Meta::Method> for delegation
methods.
=head1 METHODS
=over 4
=item B<< Moose::Meta::Method::Delegation->new(%options) >>
This creates the delegation methods based on the provided C<%options>.
=over 4
=item I<attribute>
This must be an instance of C<Moose::Meta::Attribute> which this
accessor is being generated for. This options is B<required>.
=item I<delegate_to_method>
The method in the associated attribute's value to which we
delegate. This can be either a method name or a code reference.
=item I<curried_arguments>
An array reference of arguments that will be prepended to the argument list for
any call to the delegating method.
=back
=item B<< $metamethod->associated_attribute >>
Returns the attribute associated with this method.
=item B<< $metamethod->curried_arguments >>
Return any curried arguments that will be passed to the delegated method.
=item B<< $metamethod->delegate_to_method >>
Returns the method to which this method delegates, as passed to the
constructor.
=back
=head1 BUGS
See L<Moose/BUGS> for details on reporting bugs.
=head1 AUTHOR
Dave Rolsky E<lt>autarch@urth.orgE<gt>
=head1 COPYRIGHT AND LICENSE
Copyright 2009 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
|
