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package App::Glacier::DB;
use strict;
use warnings;
use JSON;
use Carp;
use App::Glacier::Timestamp;
use parent 'Exporter';
use constant {
ENCODE => 0,
DECODE => 1
};
my %transcode = (
'storable' => [
# Encoder
\&Storable::freeze,
# Decoder
\&Storable::thaw
],
'json' => [
# Encoder
sub { JSON->new->convert_blessed(1)->encode(shift) },
# Decoder
sub { JSON->
new->
filter_json_object(sub { timestamp_deserialize $_[0] })->
decode(shift) }
]
);
sub mod_call {
my ($class, $backend, $code) = @_;
my $modname = $class . '::' . $backend;
my $modpath = $modname;
$modpath =~ s{::}{/}g;
$modpath .= '.pm';
require $modpath;
return &{$code}($modname);
};
sub new {
my ($class, $backend, %opts) = @_;
my $v;
my $self = bless { }, $class;
if ($v = delete $opts{encoding}) {
croak "unsupported encoding $v"
unless exists $transcode{$v};
$self->{_encode} = $transcode{$v}[ENCODE];
$self->{_decode} = $transcode{$v}[DECODE];
}
eval {
$class->mod_call($backend, sub { $self->{_backend} = shift->new(%opts) })
};
if ($@) {
# if ($@ =~ /Can't locate/) {
# croak "unknown backend: $backend";
# }
croak $@;
}
return undef unless $self->{_backend};
return $self;
}
sub configtest {
my ($class, $backend, $cfg, @path) = @_;
my $res;
eval {
$res = $class->mod_call($backend,
sub {
shift->configtest($cfg, @path)
});
};
if ($@) {
croak $@;
}
return $res;
}
sub backend { shift->{_backend} }
sub decode {
my ($self, $val) = @_;
return $val unless $val && defined($self->{_decode});
# This extra assignment is necessary to avoid the
# "attempt to copy freed scalar" panic (reported at least for Perl
# 5.18.2), which is apparently due to context mismatch.
my $rv = &{$self->{_decode}}($val);
return $rv;
}
sub encode {
my ($self, $val) = @_;
return $val unless defined($self->{_encode});
return &{$self->{_encode}}($val);
}
sub retrieve {
my ($self, $key) = @_;
return $self->decode($self->backend->retrieve($key));
}
sub store {
my ($self, $key, $val) = @_;
return $self->backend->store($key, $self->encode($val));
}
sub foreach {
my ($self, $code) = @_;
croak "argument must be a CODE" unless ref($code) eq 'CODE';
$self->backend->foreach(sub {
my ($key, $val) = @_;
&{$code}($key, $self->decode($val));
});
}
our $AUTOLOAD;
sub AUTOLOAD {
my $self = shift;
(my $meth = $AUTOLOAD) =~ s/.*:://;
$self->backend->${\$meth}(@_);
}
1;
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