#!/usr/bin/env perl

use strict;
use warnings;
use DB_File::Lock;

my $fileName = "/tmp/cache.db";
my %data;

my $locking = {
  'mode' => 'write',
  'nonblocking' => 0,
  'lockfile_name' => $fileName."lock",
  'lockfile_mode' => 0600,
};

unless (-e $fileName) {
  print "creating $fileName\n";
  tie(%data, 'DB_File::Lock', $fileName, O_CREAT, 0664, $DB_HASH, $locking);
  untie(%data);
} 

print "re-opening $fileName\n";

tie %data, 'DB_File::Lock', $fileName, O_RDWR, 0664, $DB_HASH, $locking
  or die "Error tieing file $fileName: $!";

my $time = $data{"time"};

print "found foo=".$data{"foo"}."\n" if exists $data{"foo"};
print "found time=".$data{"time"}."\n" if exists $data{"time"};

$data{"foo"} = "bar";
$data{"time"} = time();

untie(%data);