From: short <>
Date: Sat, 17 Sep 2005 12:03:10 +0000 (+0000)
Subject: +Hash tied to restrict access to the specified keys list.
X-Git-Url: http://git.jankratochvil.net/?p=MyWeb.git;a=commitdiff_plain;h=a76d950284c79e8e569d5c9101ad04c4f8c736ae

+Hash tied to restrict access to the specified keys list.
---

diff --git a/Hash/Makefile.am b/Hash/Makefile.am
index 0c70402..7a7d772 100644
--- a/Hash/Makefile.am
+++ b/Hash/Makefile.am
@@ -19,7 +19,8 @@
 include $(top_srcdir)/Makefile-head.am
 
 EXTRA_DIST+= \
-		Push.pm
-		Sub.pm
-		Readonly.pm
+		Push.pm \
+		Sub.pm \
+		Readonly.pm \
+		RestrictTo.pm
 
diff --git a/Hash/RestrictTo.pm b/Hash/RestrictTo.pm
new file mode 100644
index 0000000..d11501b
--- /dev/null
+++ b/Hash/RestrictTo.pm
@@ -0,0 +1,106 @@
+# $Id$
+# Hash tied to restrict access to the specified keys list.
+# 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::RestrictTo;
+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($$@)
+{
+my($class,$parent,@keys)=@_;
+
+	my $self=$class->SUPER::TIEHASH($parent);
+	$self->{"keyshash"}={ map(($_=>1),@keys) };
+	return $self;
+}
+
+sub STORE($$$)
+{
+my($this,$key,$value)=@_;
+
+	confess "Key not permitted: $key" if !$this->{"keyshash"}{$key};
+	return $this->pass("STORE",$key,$value);
+}
+
+sub FETCH($$)
+{
+my($this,$key)=@_;
+
+	confess "Key not permitted: $key" if !$this->{"keyshash"}{$key};
+	return $this->pass("FETCH",$key);
+}
+
+sub FIRSTKEY($)
+{
+my($this)=@_;
+
+	my $a=keys(%{$this->{"keyshash"}});
+	return $this->NEXTKEY($this,undef());
+}
+
+sub NEXTKEY($$)
+{
+my($this,$lastkey)=@_;
+
+cluck "TODO: Enumeration may not be expected.";
+	for (;;) {
+		my $key=each(%{$this->{"keyshash"}});
+		return if !defined $key;
+		return $key if exists $this->{"parent"}{$key};
+		}
+}
+
+sub EXISTS($$)
+{
+my($this,$key)=@_;
+
+	confess "Key not permitted: $key" if !$this->{"keyshash"}{$key};
+	return $this->pass("EXISTS",$key);
+}
+
+sub DELETE($$)
+{
+my($this,$key)=@_;
+
+	confess "Key not permitted: $key" if !$this->{"keyshash"}{$key};
+	return $this->pass("DELETE",$key);
+}
+
+sub CLEAR($)
+{
+my($this)=@_;
+
+cluck "TODO: Enumeration may not be expected.";
+	delete $this->{"parent"}{$_} for keys(%{$this->{"keyshash"}});
+}
+
+sub SCALAR
+{
+my($this)=@_;
+
+confess "TODO: Not yet implemented.";
+}
+
+1;