[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   = '1.12';
$VERSION = eval $VERSION;
our $AUTHORITY = 'cpan:STEVAN';

use constant DEBUG_NO_META => $ENV{DEBUG_NO_META} ? 1 : 0;

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')
                && !$_[0]->isa('Class::MOP::Mixin')
                # 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);
}

sub _make_compatible_with {
    my $self = shift;
    my ($other) = @_;

    # XXX: this is pretty gross. the issue here is that CMOP::Method::Meta
    # objects are subclasses of CMOP::Method, but when we get to moose, they'll
    # need to be compatible with Moose::Meta::Method, which isn't possible. the
    # right solution here is to make ::Meta into a role that gets applied to
    # whatever the method_metaclass happens to be and get rid of
    # _meta_method_metaclass entirely, but that's not going to happen until
    # we ditch cmop and get roles into the bootstrapping, so. i'm not
    # maintaining the previous behavior of turning them into instances of the
    # new method_metaclass because that's equally broken, and at least this way
    # any issues will at least be detectable and potentially fixable. -doy
    return $self unless $other->_is_compatible_with($self->_real_ref_name);

    return $self->SUPER::_make_compatible_with(@_);
}

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
bd2550f8	10	our $VERSION = '1.12';
59b51046	11	$VERSION = eval $VERSION;
	12	our $AUTHORITY = 'cpan:STEVAN';
	13
684b69cf	14	use constant DEBUG_NO_META => $ENV{DEBUG_NO_META} ? 1 : 0;
59b51046	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')
23ab51e4	34	&& !$_[0]->isa('Class::MOP::Mixin')
28a82dda	35	# it's okay if the test itself calls ->meta, we only care about
	36	# if the mop internals call ->meta
	37	&& $method_self->_is_caller_mop_internal(scalar caller);
59b51046	38	}
	39	# we must re-initialize so that it
	40	# works as expected in subclasses,
	41	# since metaclass instances are
	42	# singletons, this is not really a
	43	# big deal anyway.
	44	$metaclass->initialize(blessed($_[0]) \|\| $_[0])
	45	};
	46	}
	47
	48	sub wrap {
	49	my ($class, @args) = @_;
	50
	51	unshift @args, 'body' if @args % 2 == 1;
	52	my %params = @args;
	53	confess "Overriding the body of meta methods is not allowed"
	54	if $params{body};
	55
	56	my $metaclass_class = $params{associated_metaclass}->meta;
	57	$params{body} = $class->_generate_meta_method($metaclass_class);
	58	return $class->SUPER::wrap(%params);
	59	}
	60
5281e1f9	61	sub _make_compatible_with {
	62	my $self = shift;
	63	my ($other) = @_;
	64
	65	# XXX: this is pretty gross. the issue here is that CMOP::Method::Meta
	66	# objects are subclasses of CMOP::Method, but when we get to moose, they'll
	67	# need to be compatible with Moose::Meta::Method, which isn't possible. the
	68	# right solution here is to make ::Meta into a role that gets applied to
	69	# whatever the method_metaclass happens to be and get rid of
	70	# _meta_method_metaclass entirely, but that's not going to happen until
	71	# we ditch cmop and get roles into the bootstrapping, so. i'm not
	72	# maintaining the previous behavior of turning them into instances of the
	73	# new method_metaclass because that's equally broken, and at least this way
	74	# any issues will at least be detectable and potentially fixable. -doy
	75	return $self unless $other->_is_compatible_with($self->_real_ref_name);
	76
	77	return $self->SUPER::_make_compatible_with(@_);
	78	}
	79
59b51046	80	1;
	81
	82	__END__
	83
	84	=pod
	85
	86	=head1 NAME
	87
	88	Class::MOP::Method::Meta - Method Meta Object for C<meta> methods
	89
	90	=head1 DESCRIPTION
	91
	92	This is a L<Class::MOP::Method> subclass which represents C<meta>
	93	methods installed into classes by Class::MOP.
	94
	95	=head1 METHODS
	96
	97	=over 4
	98
	99	=item B<< Class::MOP::Method::Wrapped->wrap($metamethod, %options) >>
	100
	101	This is the constructor. It accepts a L<Class::MOP::Method> object and
	102	a hash of options. The options accepted are identical to the ones
	103	accepted by L<Class::MOP::Method>, except that C<body> cannot be passed
	104	(it will be generated automatically).
	105
	106	=back
	107
	108	=head1 AUTHORS
	109
	110	Jesse Luehrs E<lt>doy at tozt dot netE<gt>
	111
	112	=head1 COPYRIGHT AND LICENSE
	113
	114	Copyright 2006-2010 by Infinity Interactive, Inc.
	115
	116	L<http://www.iinteractive.com>
	117
	118	This library is free software; you can redistribute it and/or modify
	119	it under the same terms as Perl itself.
	120
	121	=cut
	122