package MooseX::Storage::Engine;
use Moose;
+our $VERSION = '0.01';
+
+# the class marker when
+# serializing an object.
+our $CLASS_MARKER = '__CLASS__';
+
has 'storage' => (
- is => 'rw',
+ is => 'ro',
+ isa => 'HashRef',
+ default => sub {{}}
+);
+
+has 'seen' => (
+ is => 'ro',
isa => 'HashRef',
default => sub {{}}
);
sub collapse_object {
my $self = shift;
+
+ # NOTE:
+ # mark the root object as seen ...
+ $self->seen->{$self->object} = undef;
+
$self->map_attributes('collapse_attribute');
- $self->storage->{'__class__'} = $self->object->meta->name;
+ $self->storage->{$CLASS_MARKER} = $self->object->meta->name;
return $self->storage;
}
sub expand_object {
my ($self, $data) = @_;
+
+ # NOTE:
+ # mark the root object as seen ...
+ $self->seen->{$data} = undef;
+
$self->map_attributes('expand_attribute', $data);
return $self->storage;
}
sub collapse_attribute_value {
my ($self, $attr) = @_;
my $value = $attr->get_value($self->object);
+
+ $self->check_for_cycle_in_collapse($value)
+ if ref $value;
+
if (defined $value && $attr->has_type_constraint) {
- my $type_converter = $self->match_type($attr->type_constraint);
+ my $type_converter = $self->find_type_handler($attr->type_constraint);
(defined $type_converter)
|| confess "Cannot convert " . $attr->type_constraint->name;
$value = $type_converter->{collapse}->($value);
sub expand_attribute_value {
my ($self, $attr, $value) = @_;
+
+ $self->check_for_cycle_in_expansion($value)
+ if ref $value;
+
if (defined $value && $attr->has_type_constraint) {
- my $type_converter = $self->match_type($attr->type_constraint);
+ my $type_converter = $self->find_type_handler($attr->type_constraint);
$value = $type_converter->{expand}->($value);
}
return $value;
# util methods ...
+sub check_for_cycle_in_collapse {
+ my ($self, $value) = @_;
+ (!exists $self->seen->{$value})
+ || confess "Basic Engine does not support cycles";
+ $self->seen->{$value} = undef;
+}
+
+sub check_for_cycle_in_expansion {
+ my ($self, $value) = @_;
+ (!exists $self->seen->{$value})
+ || confess "Basic Engine does not support cycles";
+ $self->seen->{$value} = undef;
+}
+
sub map_attributes {
my ($self, $method_name, @args) = @_;
map {
}
## ------------------------------------------------------------------
-## Everything below here might need some re-thinking ...
+## This is all the type handler stuff, it is in a state of flux
+## right now, so this may change, or it may just continue to be
+## improved upon. Comments and suggestions are welcomed.
## ------------------------------------------------------------------
# NOTE:
my %OBJECT_HANDLERS = (
expand => sub {
my $data = shift;
- (exists $data->{'__class__'})
+ (exists $data->{$CLASS_MARKER})
|| confess "Serialized item has no class marker";
- $data->{'__class__'}->unpack($data);
+ $data->{$CLASS_MARKER}->unpack($data);
},
collapse => sub {
my $obj = shift;
my %TYPES = (
+ # These are boring ones, so they use the identity function ...
'Int' => { expand => sub { shift }, collapse => sub { shift } },
'Num' => { expand => sub { shift }, collapse => sub { shift } },
'Str' => { expand => sub { shift }, collapse => sub { shift } },
+ # These are the trickier ones, (see notes)
+ # NOTE:
+ # Because we are nice guys, we will check
+ # your ArrayRef and/or HashRef one level
+ # down and inflate any objects we find.
+ # But this is where it ends, it is too
+ # expensive to try and do this any more
+ # recursively, when it is probably not
+ # nessecary in most of the use cases.
+ # However, if you need more then this, subtype
+ # and add a custom handler.
'ArrayRef' => {
- # FIXME:
- # these should also probably be
- # recursive as well, so they
- # can handle arbitrarily deep
- # arrays and such. Or perhaps
- # we force the user to handle
- # the types in a custom way.
- # This would require a more
- # sophisticated way of handling
- # this %TYPES hash.
expand => sub {
my $array = shift;
foreach my $i (0 .. $#{$array}) {
next unless ref($array->[$i]) eq 'HASH'
- && exists $array->[$i]->{'__class__'};
+ && exists $array->[$i]->{$CLASS_MARKER};
$array->[$i] = $OBJECT_HANDLERS{expand}->($array->[$i])
}
$array;
}
},
'HashRef' => {
- expand => sub { shift },
- collapse => sub { shift }
+ expand => sub {
+ my $hash = shift;
+ foreach my $k (keys %$hash) {
+ next unless ref($hash->{$k}) eq 'HASH'
+ && exists $hash->{$k}->{$CLASS_MARKER};
+ $hash->{$k} = $OBJECT_HANDLERS{expand}->($hash->{$k})
+ }
+ $hash;
+ },
+ collapse => sub {
+ my $hash = shift;
+ # NOTE:
+ # we need to make a copy cause
+ # otherwise it will affect the
+ # other real version.
+ +{ map {
+ blessed($hash->{$_})
+ ? ($_ => $OBJECT_HANDLERS{collapse}->($hash->{$_}))
+ : ($_ => $hash->{$_})
+ } keys %$hash }
+ }
},
'Object' => \%OBJECT_HANDLERS,
# NOTE:
#'CodeRef' => {
# expand => sub {}, # use eval ...
# collapse => sub {}, # use B::Deparse ...
- #}
+ #}
);
-sub match_type {
+sub add_custom_type_handler {
+ my ($class, $type_name, %handlers) = @_;
+ (exists $handlers{expand} && exists $handlers{collapse})
+ || confess "Custom type handlers need an expand *and* a collapse method";
+ $TYPES{$type_name} = \%handlers;
+}
+
+sub remove_custom_type_handler {
+ my ($class, $type_name) = @_;
+ delete $TYPES{$type_name} if exists $TYPES{$type_name};
+}
+
+sub find_type_handler {
my ($self, $type_constraint) = @_;
# this should handle most type usages
# totally out the door ;)
# - SL
-
- # To cover the last possibilities we
- # need a way for people to extend this
- # process. Which they can do by subclassing
- # this class and overriding the method
- # below to handle things.
- my $match = $self->_custom_type_match($type_constraint);
- return $match if defined $match;
-
# NOTE:
# if this method hasnt returned by now
# then we have no been able to find a
confess "Cannot handle type constraint (" . $type_constraint->name . ")";
}
-sub _custom_type_match {
- return;
- # my ($self, $type_constraint) = @_;
-}
-
1;
__END__
=item B<map_attributes>
-=item B<match_type>
+=back
+
+=head2 Type Constraint Handlers
+
+=over 4
+
+=item B<find_type_handler>
+
+=item B<add_custom_type_handler>
+
+=item B<remove_custom_type_handler>
=back
projects / gitmo/MooseX-Storage.git / blobdiff