just a simple XSLoader for now

[gitmo/Mouse.git] / lib / Mouse / Util.pm

#!/usr/bin/env perl
package Mouse::Util;
use strict;
use warnings;
use base 'Exporter';
use Carp;

BEGIN {
    our %dependencies = (
        'Scalar::Util' => {

#       VVVVV   CODE TAKEN FROM SCALAR::UTIL   VVVVV
            'blessed' => do {
                *UNIVERSAL::a_sub_not_likely_to_be_here = sub {
                    my $ref = ref($_[0]);

                    # deviation from Scalar::Util
                    # XS returns undef, PP returns GLOB.
                    # let's make that more consistent by having PP return
                    # undef if it's a GLOB. :/

                    # \*STDOUT would be allowed as an object in PP blessed
                    # but not XS
                    return $ref eq 'GLOB' ? undef : $ref;
                };

                sub {
                    local($@, $SIG{__DIE__}, $SIG{__WARN__});
                    length(ref($_[0]))
                        ? eval { $_[0]->a_sub_not_likely_to_be_here }
                        : undef;
                },
            },
            'looks_like_number' => sub {
                local $_ = shift;

                # checks from perlfaq4
                return 0 if !defined($_) or ref($_);
                return 1 if (/^[+-]?\d+$/); # is a +/- integer
                return 1 if (/^([+-]?)(?=\d|\.\d)\d*(\.\d*)?([Ee]([+-]?\d+))?$/); # a C float
                return 1 if ($] >= 5.008 and /^(Inf(inity)?|NaN)$/i) or ($] >= 5.006001 and /^Inf$/i);

                0;
            },
            'reftype' => sub {
                local($@, $SIG{__DIE__}, $SIG{__WARN__});
                my $r = shift;
                my $t;

                length($t = ref($r)) or return undef;

                # This eval will fail if the reference is not blessed
                eval { $r->a_sub_not_likely_to_be_here; 1 }
                ? do {
                    $t = eval {
                        # we have a GLOB or an IO. Stringify a GLOB gives it's name
                        my $q = *$r;
                        $q =~ /^\*/ ? "GLOB" : "IO";
                    }
                    or do {
                        # OK, if we don't have a GLOB what parts of
                        # a glob will it populate.
                        # NOTE: A glob always has a SCALAR
                        local *glob = $r;
                        defined *glob{ARRAY} && "ARRAY"
                            or defined *glob{HASH} && "HASH"
                            or defined *glob{CODE} && "CODE"
                            or length(ref(${$r})) ? "REF" : "SCALAR";
                    }
                }
                : $t
            },
            'openhandle' => sub {
                my $fh = shift;
                my $rt = reftype($fh) || '';

                return defined(fileno($fh)) ? $fh : undef
                    if $rt eq 'IO';

                if (reftype(\$fh) eq 'GLOB') { # handle  openhandle(*DATA)
                    $fh = \(my $tmp=$fh);
                }
                elsif ($rt ne 'GLOB') {
                    return undef;
                }

                (tied(*$fh) or defined(fileno($fh)))
                    ? $fh : undef;
            },
            weaken => {
                loaded => \&Scalar::Util::weaken,
                not_loaded => sub { die "Scalar::Util required for weak reference support" },
            },
#       ^^^^^   CODE TAKEN FROM SCALAR::UTIL   ^^^^^
        },
        'MRO::Compat' => {
#       VVVVV   CODE TAKEN FROM MRO::COMPAT   VVVVV
            'get_linear_isa' => {
                loaded     => \&mro::get_linear_isa,
                not_loaded => do {
                    # this recurses so it isn't pretty
                    my $code;
                    $code = sub {
                        no strict 'refs';

                        my $classname = shift;

                        my @lin = ($classname);
                        my %stored;
                        foreach my $parent (@{"$classname\::ISA"}) {
                            my $plin = $code->($parent);
                            foreach (@$plin) {
                                next if exists $stored{$_};
                                push(@lin, $_);
                                $stored{$_} = 1;
                            }
                        }
                        return \@lin;
                    }
                },
            },
#       ^^^^^   CODE TAKEN FROM MRO::COMPAT   ^^^^^
        },
    );

    our %loaded;

    our @EXPORT_OK = map { keys %$_ } values %dependencies;
    our %EXPORT_TAGS = (
        all  => \@EXPORT_OK,
    );

    for my $module_name (keys %dependencies) {
        my $loaded = do {
            local $SIG{__DIE__} = 'DEFAULT';
            eval "require $module_name; 1";
        };

        $loaded{$module_name} = $loaded;

        for my $method_name (keys %{ $dependencies{ $module_name } }) {
            my $producer = $dependencies{$module_name}{$method_name};
            my $implementation;

            if (ref($producer) eq 'HASH') {
                $implementation = $loaded
                                ? $producer->{loaded}
                                : $producer->{not_loaded};
            }
            else {
                $implementation = $loaded
                                ? $module_name->can($method_name)
                                : $producer;
            }

            no strict 'refs';
            *{ __PACKAGE__ . '::' . $method_name } = $implementation;
        }
    }
}

sub apply_all_roles {
    my $meta = Mouse::Meta::Class->initialize(shift);
    my $role  = shift;
    confess "Mouse::Util only supports 'apply_all_roles' on individual roles at a time" if @_;

    Mouse::load_class($role);
    $role->meta->apply($meta);
}

1;

__END__

=head1 NAME

Mouse::Util - features, with or without their dependencies

=head1 IMPLEMENTATIONS FOR

=head2 L<MRO::Compat>

=head3 get_linear_isa

=head2 L<Scalar::Util>

=head3 blessed

=head3 looks_like_number

=head3 reftype

=head3 openhandle

=head3 weaken

C<weaken> I<must> be implemented in XS. If the user tries to use C<weaken>
without L<Scalar::Util>, an error is thrown.

=head2 Test::Exception

=head3 throws_ok

=head3 lives_ok

=cut