use strict;
use warnings FATAL => 'all';
+our $VERSION = $DBM::Deep::VERSION;
+
use DBM::Deep::Iterator ();
# File-wide notes:
# mutex. But, it's the caller's responsability to make sure that this has
# been done.
+sub SIG_HASH () { 'H' }
+sub SIG_ARRAY () { 'A' }
+
=head1 NAME
DBM::Deep::Engine
=head1 PURPOSE
-This is an internal-use-only object for L<DBM::Deep/>. It mediates the low-level
-mapping between the L<DBM::Deep/> objects and the storage medium.
+This is an internal-use-only object for L<DBM::Deep>. It mediates the low-level
+mapping between the L<DBM::Deep> objects and the storage medium.
The purpose of this documentation is to provide low-level documentation for
developers. It is B<not> intended to be used by the general public. This
=head2 write_value( $obj, $key, $value )
This takes an object that provides _base_offset(), a string for the
-key, and a value. This value can be anything storable within L<DBM::Deep/>.
+key, and a value. This value can be anything storable within L<DBM::Deep>.
This returns 1 upon success.
# XXX Need to add logic about resetting the iterator if any key in the
# reference has changed
- unless ( $prev_key ) {
- $obj->{iterator} = DBM::Deep::Iterator->new({
+ unless ( defined $prev_key ) {
+ $obj->{iterator} = $self->iterator_class->new({
base_offset => $obj->_base_offset,
engine => $self,
});
sub load_sector { $_[0]->sector_type->load( @_ ) }
+=head2 cache / clear_cache
+
+This is the cache of loaded Reference sectors.
+
+=cut
+
+sub cache { $_[0]{cache} ||= {} }
+sub clear_cache { %{$_[0]->cache} = () }
+
+=head2 supports( $option )
+
+This returns a boolean depending on if this instance of DBM::Dep supports
+that feature. C<$option> can be one of:
+
+=over 4
+
+=item * transactions
+
+=back
+
+=cut
+
+sub supports { die "supports must be implemented in a child class" }
+
=head2 ACCESSORS
The following are readonly attributes.
=item * storage
+=item * sector_type
+
=back
=cut
sub sector_type { die "sector_type must be implemented in a child class" }
+# This code is to make sure we write all the values in the $value to the
+# disk and to make sure all changes to $value after the assignment are
+# reflected on disk. This may be counter-intuitive at first, but it is
+# correct dwimmery.
+# NOTE - simply tying $value won't perform a STORE on each value. Hence,
+# the copy to a temp value.
+sub _descend {
+ my $self = shift;
+ my ($value, $value_sector) = @_;
+ my $r = Scalar::Util::reftype( $value ) || '';
+
+ if ( $r eq 'ARRAY' ) {
+ my @temp = @$value;
+ tie @$value, 'DBM::Deep', {
+ base_offset => $value_sector->offset,
+ staleness => $value_sector->staleness,
+ storage => $self->storage,
+ engine => $self,
+ };
+ @$value = @temp;
+ bless $value, 'DBM::Deep::Array' unless Scalar::Util::blessed( $value );
+ }
+ elsif ( $r eq 'HASH' ) {
+ my %temp = %$value;
+ tie %$value, 'DBM::Deep', {
+ base_offset => $value_sector->offset,
+ staleness => $value_sector->staleness,
+ storage => $self->storage,
+ engine => $self,
+ };
+ %$value = %temp;
+ bless $value, 'DBM::Deep::Hash' unless Scalar::Util::blessed( $value );
+ }
+}
+
1;
__END__