package Module::Loaded;

use strict;
use Carp qw[carp];

BEGIN { use base 'Exporter';
use vars qw[@EXPORT $VERSION];

$VERSION = '0.08';
@EXPORT = qw[mark_as_loaded mark_as_unloaded is_loaded];
}

=head1 NAME

Module::Loaded - mark modules as loaded or unloaded

=head1 SYNOPSIS

use Module::Loaded;

$bool = mark_as_loaded('Foo'); # Foo.pm is now marked as loaded
$loc = is_loaded('Foo'); # location of Foo.pm set to the
# loaders location
eval "require 'Foo'"; # is now a no-op

$bool = mark_as_unloaded('Foo'); # Foo.pm no longer marked as loaded
eval "require 'Foo'"; # Will try to find Foo.pm in @INC

=head1 DESCRIPTION

When testing applications, often you find yourself needing to provide
functionality in your test environment that would usually be provided
by external modules. Rather than munging the C<%INC> by hand to mark
these external modules as loaded, so they are not attempted to be loaded
by perl, this module offers you a very simple way to mark modules as
loaded and/or unloaded.

=head1 FUNCTIONS

=head2 $bool = mark_as_loaded( PACKAGE );

Marks the package as loaded to perl. C<PACKAGE> can be a bareword or
string.

If the module is already loaded, C<mark_as_loaded> will carp about
this and tell you from where the C<PACKAGE> has been loaded already.

=cut

sub mark_as_loaded (*) {
my $pm = shift;
my $file = __PACKAGE__->_pm_to_file( $pm ) or return;
my $who = [caller]->[1];

my $where = is_loaded( $pm );
if ( defined $where ) {
carp "'$pm' already marked as loaded ('$where')";

} else {
$INC{$file} = $who;
}

return 1;
}

=head2 $bool = mark_as_unloaded( PACKAGE );

Marks the package as unloaded to perl, which is the exact opposite
of C<mark_as_loaded>. C<PACKAGE> can be a bareword or string.

If the module is already unloaded, C<mark_as_unloaded> will carp about
this and tell you the C<PACKAGE> has been unloaded already.

=cut

sub mark_as_unloaded (*) {
my $pm = shift;
my $file = __PACKAGE__->_pm_to_file( $pm ) or return;

unless( defined is_loaded( $pm ) ) {
carp "'$pm' already marked as unloaded";

} else {
delete $INC{ $file };
}

return 1;
}

=head2 $loc = is_loaded( PACKAGE );

C<is_loaded> tells you if C<PACKAGE> has been marked as loaded yet.
C<PACKAGE> can be a bareword or string.

It returns falls if C<PACKAGE> has not been loaded yet and the location
from where it is said to be loaded on success.

=cut

sub is_loaded (*) {
my $pm = shift;
my $file = __PACKAGE__->_pm_to_file( $pm ) or return;

return $INC{$file} if exists $INC{$file};

return;
}


sub _pm_to_file {
my $pkg = shift;
my $pm = shift or return;

my $file = join '/', split '::', $pm;
$file .= '.pm';

return $file;
}

=head1 BUG REPORTS

Please report bugs or other issues to E<lt>[email protected]<gt>.

=head1 AUTHOR

This module by Jos Boumans E<lt>[email protected]<gt>.

=head1 COPYRIGHT

This library is free software; you may redistribute and/or modify it
under the same terms as Perl itself.

=cut

# Local variables:
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1;