[gitmo/Class-MOP.git] / lib / Class / MOP / Method / Meta.pm


package Class::MOP::Method::Meta;

use strict;
use warnings;

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

our $VERSION   = '1.08';
$VERSION = eval $VERSION;
our $AUTHORITY = 'cpan:STEVAN';

use constant DEBUG_NO_META => $ENV{DEBUG_NO_META};

use base 'Class::MOP::Method';

sub _is_caller_mop_internal {
    my $self = shift;
    my ($caller) = @_;
    return $caller =~ /^(?:Class::MOP|metaclass)(?:::|$)/;
}

sub _generate_meta_method {
    my $method_self = shift;
    my $metaclass   = shift;
    sub {
        # this will be compiled out if the env var wasn't set
        if (DEBUG_NO_META) {
            confess "'meta' method called by MOP internals"
                # it's okay to call meta methods on metaclasses, since we
                # explicitly ask for them
                if !$_[0]->isa('Class::MOP::Object')
                # it's okay if the test itself calls ->meta, we only care about
                # if the mop internals call ->meta
                && $method_self->_is_caller_mop_internal(scalar caller);
        }
        # we must re-initialize so that it
        # works as expected in subclasses,
        # since metaclass instances are
        # singletons, this is not really a
        # big deal anyway.
        $metaclass->initialize(blessed($_[0]) || $_[0])
    };
}

sub wrap {
    my ($class, @args) = @_;

    unshift @args, 'body' if @args % 2 == 1;
    my %params = @args;
    confess "Overriding the body of meta methods is not allowed"
        if $params{body};

    my $metaclass_class = $params{associated_metaclass}->meta;
    $params{body} = $class->_generate_meta_method($metaclass_class);
    return $class->SUPER::wrap(%params);
}

1;

__END__

=pod

=head1 NAME

Class::MOP::Method::Meta - Method Meta Object for C<meta> methods

=head1 DESCRIPTION

This is a L<Class::MOP::Method> subclass which represents C<meta>
methods installed into classes by Class::MOP.

=head1 METHODS

=over 4

=item B<< Class::MOP::Method::Wrapped->wrap($metamethod, %options) >>

This is the constructor. It accepts a L<Class::MOP::Method> object and
a hash of options. The options accepted are identical to the ones
accepted by L<Class::MOP::Method>, except that C<body> cannot be passed
(it will be generated automatically).

=back

=head1 AUTHORS

Jesse Luehrs E<lt>doy at tozt dot netE<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
Commit	Line	Data
59b51046	1
	2	package Class::MOP::Method::Meta;
	3
	4	use strict;
	5	use warnings;
	6
	7	use Carp 'confess';
	8	use Scalar::Util 'blessed';
	9
	10	our $VERSION = '1.08';
	11	$VERSION = eval $VERSION;
	12	our $AUTHORITY = 'cpan:STEVAN';
	13
	14	use constant DEBUG_NO_META => $ENV{DEBUG_NO_META};
	15
	16	use base 'Class::MOP::Method';
	17
28a82dda	18	sub _is_caller_mop_internal {
	19	my $self = shift;
	20	my ($caller) = @_;
	21	return $caller =~ /^(?:Class::MOP\|metaclass)(?:::\|$)/;
	22	}
	23
59b51046	24	sub _generate_meta_method {
	25	my $method_self = shift;
	26	my $metaclass = shift;
	27	sub {
	28	# this will be compiled out if the env var wasn't set
	29	if (DEBUG_NO_META) {
59b51046	30	confess "'meta' method called by MOP internals"
28a82dda	31	# it's okay to call meta methods on metaclasses, since we
	32	# explicitly ask for them
	33	if !$_[0]->isa('Class::MOP::Object')
	34	# it's okay if the test itself calls ->meta, we only care about
	35	# if the mop internals call ->meta
	36	&& $method_self->_is_caller_mop_internal(scalar caller);
59b51046	37	}
	38	# we must re-initialize so that it
	39	# works as expected in subclasses,
	40	# since metaclass instances are
	41	# singletons, this is not really a
	42	# big deal anyway.
	43	$metaclass->initialize(blessed($_[0]) \|\| $_[0])
	44	};
	45	}
	46
	47	sub wrap {
	48	my ($class, @args) = @_;
	49
	50	unshift @args, 'body' if @args % 2 == 1;
	51	my %params = @args;
	52	confess "Overriding the body of meta methods is not allowed"
	53	if $params{body};
	54
	55	my $metaclass_class = $params{associated_metaclass}->meta;
	56	$params{body} = $class->_generate_meta_method($metaclass_class);
	57	return $class->SUPER::wrap(%params);
	58	}
	59
	60	1;
	61
	62	__END__
	63
	64	=pod
	65
	66	=head1 NAME
	67
	68	Class::MOP::Method::Meta - Method Meta Object for C<meta> methods
	69
	70	=head1 DESCRIPTION
	71
	72	This is a L<Class::MOP::Method> subclass which represents C<meta>
	73	methods installed into classes by Class::MOP.
	74
	75	=head1 METHODS
	76
	77	=over 4
	78
	79	=item B<< Class::MOP::Method::Wrapped->wrap($metamethod, %options) >>
	80
	81	This is the constructor. It accepts a L<Class::MOP::Method> object and
	82	a hash of options. The options accepted are identical to the ones
	83	accepted by L<Class::MOP::Method>, except that C<body> cannot be passed
	84	(it will be generated automatically).
	85
	86	=back
	87
	88	=head1 AUTHORS
	89
	90	Jesse Luehrs E<lt>doy at tozt dot netE<gt>
	91
	92	=head1 COPYRIGHT AND LICENSE
	93
	94	Copyright 2006-2010 by Infinity Interactive, Inc.
	95
	96	L<http://www.iinteractive.com>
	97
	98	This library is free software; you can redistribute it and/or modify
	99	it under the same terms as Perl itself.
	100
101	=cut
102