# $Id$
# Hash tied to record all the accessed keys.
# Copyright (C) 2005 Jan Kratochvil <project-www.jankratochvil.net@jankratochvil.net>
# 
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation; exactly version 2 of June 1991 is required
# 
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
# 
# You should have received a copy of the GNU General Public License
# along with this program; if not, write to the Free Software
# Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA


package My::Hash::RecordKeys;
our $VERSION=do { my @r=(q$Revision$=~/\d+/g); sprintf "%d.".("%03d"x$#r),@r; };
our $CVS_ID=q$Id$;
use strict;
use warnings;
use My::Web;	# for &Wrequire
Wrequire 'My::Hash';
our @ISA=qw(My::Hash);
use Carp qw(cluck confess);


sub TIEHASH($$)
{
my($class,$parent)=@_;

	my $self=$class->SUPER::TIEHASH($parent);
	$self->{"keyshash"}={};
	return $self;
}

# Call as: my @accessed=tied(%$ref)->accessed();
sub accessed($)
{
my($self)=@_;

	return sort keys(%{$self->{"keyshash"}})
}

sub STORE($$$)
{
my($this,$key,$value)=@_;

	$this->{"keyshash"}{$key}=1;
	return $this->pass("STORE",$key,$value);
}

sub FETCH($$)
{
my($this,$key)=@_;

	$this->{"keyshash"}{$key}=1;
	return $this->pass("FETCH",$key);
}

sub FIRSTKEY($)
{
my($this)=@_;

	my $a=keys(%{$this->{"parent"}});
	return $this->NEXTKEY($this,undef());
}

sub NEXTKEY($$)
{
my($this,$lastkey)=@_;

cluck "TODO: Enumeration may not be expected.";
	for (;;) {
		my $key=each(%{$this->{"parent"}});
		return if !defined $key;
		$this->{"keyshash"}{$key}=1;
		return $key 
		}
}

sub EXISTS($$)
{
my($this,$key)=@_;

	$this->{"keyshash"}{$key}=1;
	return $this->pass("EXISTS",$key);
}

sub DELETE($$)
{
my($this,$key)=@_;

	$this->{"keyshash"}{$key}=1;
	return $this->pass("DELETE",$key);
}

sub CLEAR($)
{
my($this)=@_;

confess "TODO: Not implementable.";
}

sub SCALAR
{
my($this)=@_;

confess "TODO: Not yet implemented.";
}

1;