update changelog for 2.0001 release

[gitmo/Moose.git] / lib / Moose / Meta / Method / Destructor.pm

package Moose::Meta::Method::Destructor;

use strict;
use warnings;

use Devel::GlobalDestruction ();
use Scalar::Util 'blessed', 'weaken';
use Try::Tiny;

use base 'Moose::Meta::Method',
         'Class::MOP::Method::Inlined';

sub new {
    my $class   = shift;
    my %options = @_;

    (ref $options{options} eq 'HASH')
        || $class->throw_error("You must pass a hash of options", data => $options{options});

    ($options{package_name} && $options{name})
        || $class->throw_error("You must supply the package_name and name parameters $Class::MOP::Method::UPGRADE_ERROR_TEXT");

    my $self = bless {
        # from our superclass
        'body'                 => undef,
        'package_name'         => $options{package_name},
        'name'                 => $options{name},
        # ...
        'options'              => $options{options},
        'associated_metaclass' => $options{metaclass},
    } => $class;

    # we don't want this creating
    # a cycle in the code, if not
    # needed
    weaken($self->{'associated_metaclass'});

    $self->_initialize_body;

    return $self;
}

## accessors

sub options              { (shift)->{'options'}              }

## method

sub is_needed {
    my $self      = shift;
    my $metaclass = shift;

    ( blessed $metaclass && $metaclass->isa('Class::MOP::Class') )
        || $self->throw_error(
        "The is_needed method expected a metaclass object as its arugment");

    return $metaclass->find_method_by_name("DEMOLISHALL");
}

sub initialize_body {
    Carp::cluck('The initialize_body method has been made private.'
        . " The public version is deprecated and will be removed in a future release.\n");
    shift->_initialize_body;
}

sub _initialize_body {
    my $self = shift;
    # TODO:
    # the %options should also include a both
    # a call 'initializer' and call 'SUPER::'
    # options, which should cover approx 90%
    # of the possible use cases (even if it
    # requires some adaption on the part of
    # the author, after all, nothing is free)

    my $class = $self->associated_metaclass->name;
    my @source = (
        'sub {',
            'my $self = shift;',
            'return ' . $self->_generate_fallback_destructor('$self'),
                'if Scalar::Util::blessed($self) ne \'' . $class . '\';',
            $self->_generate_DEMOLISHALL('$self'),
        '}',
    );
    warn join("\n", @source) if $self->options->{debug};

    my $code = try {
        $self->_compile_code(source => \@source);
    }
    catch {
        my $source = join("\n", @source);
        $self->throw_error(
            "Could not eval the destructor :\n\n$source\n\nbecause :\n\n$_",
            error => $_,
            data  => $source,
        );
    };

    $self->{'body'} = $code;
}

sub _generate_fallback_destructor {
    my $self = shift;
    my ($inv) = @_;

    return $inv . '->Moose::Object::DESTROY(@_)';
}

sub _generate_DEMOLISHALL {
    my $self = shift;
    my ($inv) = @_;

    my @methods = $self->associated_metaclass->find_all_methods_by_name('DEMOLISH');
    return unless @methods;

    return (
        'local $?;',
        'my $igd = Devel::GlobalDestruction::in_global_destruction;',
        'Try::Tiny::try {',
            (map { $inv . '->' . $_->{class} . '::DEMOLISH($igd);' } @methods),
        '}',
        'Try::Tiny::catch {',
            'no warnings \'misc\';',
            'die $_;',
        '};',
        'return;',
    );
}


1;

# ABSTRACT: Method Meta Object for destructors

__END__

=pod

=head1 DESCRIPTION

This class is a subclass of L<Class::MOP::Class::Generated> that
provides Moose-specific functionality for inlining destructors.

To understand this class, you should read the the
L<Class::MOP::Class::Generated> documentation as well.

=head1 INHERITANCE

C<Moose::Meta::Method::Destructor> is a subclass of
L<Moose::Meta::Method> I<and> L<Class::MOP::Method::Generated>.

=head1 METHODS

=over 4

=item B<< Moose::Meta::Method::Destructor->new(%options) >>

This constructs a new object. It accepts the following options:

=over 8

=item * package_name

The package for the class in which the destructor is being
inlined. This option is required.

=item * name

The name of the destructor method. This option is required.

=item * metaclass

The metaclass for the class this destructor belongs to. This is
optional, as it can be set later by calling C<<
$metamethod->attach_to_class >>.

=back

=item B<< Moose::Meta;:Method::Destructor->is_needed($metaclass) >>

Given a L<Moose::Meta::Class> object, this method returns a boolean
indicating whether the class needs a destructor. If the class or any
of its parents defines a C<DEMOLISH> method, it needs a destructor.

=back

=head1 BUGS

See L<Moose/BUGS> for details on reporting bugs.

=cut