git/perl/Git/SVN/Memoize/YAML.pm

94 lines
1.8 KiB
Perl

package Git::SVN::Memoize::YAML;
use warnings $ENV{GIT_PERL_FATAL_WARNINGS} ? qw(FATAL all) : ();
use strict;
use YAML::Any ();
# based on Memoize::Storable.
sub TIEHASH {
my $package = shift;
my $filename = shift;
my $truehash = (-e $filename) ? YAML::Any::LoadFile($filename) : {};
my $self = {FILENAME => $filename, H => $truehash};
bless $self => $package;
}
sub STORE {
my $self = shift;
$self->{H}{$_[0]} = $_[1];
}
sub FETCH {
my $self = shift;
$self->{H}{$_[0]};
}
sub EXISTS {
my $self = shift;
exists $self->{H}{$_[0]};
}
sub DESTROY {
my $self = shift;
YAML::Any::DumpFile($self->{FILENAME}, $self->{H});
}
sub SCALAR {
my $self = shift;
scalar(%{$self->{H}});
}
sub FIRSTKEY {
'Fake hash from Git::SVN::Memoize::YAML';
}
sub NEXTKEY {
undef;
}
1;
__END__
=head1 NAME
Git::SVN::Memoize::YAML - store Memoized data in YAML format
=head1 SYNOPSIS
use Memoize;
use Git::SVN::Memoize::YAML;
tie my %cache => 'Git::SVN::Memoize::YAML', $filename;
memoize('slow_function', SCALAR_CACHE => [HASH => \%cache]);
slow_function(arguments);
=head1 DESCRIPTION
This module provides a class that can be used to tie a hash to a
YAML file. The file is read when the hash is initialized and
rewritten when the hash is destroyed.
The intent is to allow L<Memoize> to back its cache with a file in
YAML format, just like L<Memoize::Storable> allows L<Memoize> to
back its cache with a file in Storable format. Unlike the Storable
format, the YAML format is platform-independent and fairly stable.
Carps on error.
=head1 DIAGNOSTICS
See L<YAML::Any>.
=head1 DEPENDENCIES
L<YAML::Any> from CPAN.
=head1 INCOMPATIBILITIES
None reported.
=head1 BUGS
The entire cache is read into a Perl hash when loading the file,
so this is not very scalable.