package Memoize::NDBM_File;

=head1 NAME

Memoize::NDBM_File - glue to provide EXISTS for NDBM_File for Storable use

=head1 DESCRIPTION

See L<Memoize>.

=cut

use NDBM_File;
@ISA = qw(NDBM_File);
$VERSION = '1.03';

$Verbose = 0;

sub AUTOLOAD {
warn "Nonexistent function $AUTOLOAD invoked in Memoize::NDBM_File\n";
}

sub import {
warn "Importing Memoize::NDBM_File\n" if $Verbose;
}


my %keylist;

# This is so ridiculous...
sub _backhash {
my $self = shift;
my %fakehash;
my $k;
for ($k = $self->FIRSTKEY(); defined $k; $k = $self->NEXTKEY($k)) {
$fakehash{$k} = undef;
}
$keylist{$self} = \%fakehash;
}

sub EXISTS {
warn "Memoize::NDBM_File EXISTS (@_)\n" if $Verbose;
my $self = shift;
_backhash($self) unless exists $keylist{$self};
my $r = exists $keylist{$self}{$_[0]};
warn "Memoize::NDBM_File EXISTS (@_) ==> $r\n" if $Verbose;
$r;
}

sub DEFINED {
warn "Memoize::NDBM_File DEFINED (@_)\n" if $Verbose;
my $self = shift;
_backhash($self) unless exists $keylist{$self};
defined $keylist{$self}{$_[0]};
}

sub DESTROY {
warn "Memoize::NDBM_File DESTROY (@_)\n" if $Verbose;
my $self = shift;
delete $keylist{$self}; # So much for reference counting...
$self->SUPER::DESTROY(@_);
}

# Maybe establish the keylist at TIEHASH time instead?

sub STORE {
warn "Memoize::NDBM_File STORE (@_)\n" if $VERBOSE;
my $self = shift;
$keylist{$self}{$_[0]} = undef;
$self->SUPER::STORE(@_);
}



# Inherit FETCH and TIEHASH

1;