package MooseX::Storage::Engine;
use Moose;
+our $VERSION = '0.02';
+
+# 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->identifier;
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);
- # TODO:
- # we want to explicitly disallow
- # cycles here, because the base
- # storage engine does not support
- # them
+
+ # NOTE:
+ # this might not be enough, we might
+ # need to make it possible for the
+ # cycle checker to return the value
+ $self->check_for_cycle_in_collapse($attr, $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) = @_;
- # TODO:
- # we need to check $value here to
- # make sure that we do not have
- # a cycle here.
+
+ # NOTE:
+ # (see comment in method above ^^)
+ $self->check_for_cycle_in_expansion($attr, $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 $value;
}
+# NOTE:
+# possibly these two methods will
+# be used by a cycle supporting
+# engine. However, I am not sure
+# if I can make a cycle one work
+# anyway.
+
+sub check_for_cycle_in_collapse {
+ my ($self, $attr, $value) = @_;
+ (!exists $self->seen->{$value})
+ || confess "Basic Engine does not support cycles in class("
+ . ($attr->associated_class->name) . ").attr("
+ . ($attr->name) . ") with $value";
+ $self->seen->{$value} = undef;
+}
+
+sub check_for_cycle_in_expansion {
+ my ($self, $attr, $value) = @_;
+ (!exists $self->seen->{$value})
+ || confess "Basic Engine does not support cycles in class("
+ . ($attr->associated_class->name) . ").attr("
+ . ($attr->name) . ") with $value";
+ $self->seen->{$value} = undef;
+}
+
# util methods ...
sub map_attributes {
my ($self, $method_name, @args) = @_;
map {
$self->$method_name($_, @args)
+ } grep {
+ # Skip our special skip attribute :)
+ !$_->isa('MooseX::Storage::Meta::Attribute::DoNotSerialize')
} ($self->object || $self->class)->meta->compute_all_applicable_attributes;
}
+## ------------------------------------------------------------------
+## 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:
+# these are needed by the
+# ArrayRef and HashRef handlers
+# below, so I need easy access
+my %OBJECT_HANDLERS = (
+ expand => sub {
+ my $data = shift;
+ (exists $data->{$CLASS_MARKER})
+ || confess "Serialized item has no class marker";
+ # check the class more thoroughly here ...
+ my ($class, $version, $authority) = (split '-' => $data->{$CLASS_MARKER});
+ my $meta = eval { $class->meta };
+ confess "Class ($class) is not loaded, cannot unpack" if $@;
+ ($meta->version eq $version)
+ || confess "Class ($class) versions don't match."
+ . " got=($version) available=(" . ($meta->version || '') . ")"
+ if defined $version;
+ ($meta->authority eq $authority)
+ || confess "Class ($class) authorities don't match."
+ . " got=($authority) available=(" . ($meta->authority || '') . ")"
+ if defined $authority;
+ # all is well ...
+ $class->unpack($data);
+ },
+ collapse => sub {
+ my $obj = shift;
+ ($obj->can('does') && $obj->does('MooseX::Storage::Basic'))
+ || confess "Bad object ($obj) does not do MooseX::Storage::Basic role";
+ $obj->pack();
+ },
+);
+
+
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 } },
- 'ArrayRef' => { expand => sub { shift }, collapse => sub { shift } },
- 'HashRef' => { expand => sub { shift }, collapse => sub { shift } },
- 'Object' => {
+ # 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' => {
expand => sub {
- my $data = shift;
- (exists $data->{'__class__'})
- || confess "Serialized item has no class marker";
- $data->{'__class__'}->unpack($data);
- },
+ my $array = shift;
+ foreach my $i (0 .. $#{$array}) {
+ next unless ref($array->[$i]) eq 'HASH'
+ && exists $array->[$i]->{$CLASS_MARKER};
+ $array->[$i] = $OBJECT_HANDLERS{expand}->($array->[$i])
+ }
+ $array;
+ },
+ collapse => sub {
+ my $array = shift;
+ # NOTE:
+ # we need to make a copy cause
+ # otherwise it will affect the
+ # other real version.
+ [ map {
+ blessed($_)
+ ? $OBJECT_HANDLERS{collapse}->($_)
+ : $_
+ } @$array ]
+ }
+ },
+ 'HashRef' => {
+ 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 $obj = shift;
- ($obj->can('does') && $obj->does('MooseX::Storage::Basic'))
- || confess "Bad object ($obj) does not do MooseX::Storage::Base role";
- $obj->pack();
- },
- }
+ 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 %$hash }
+ }
+ },
+ 'Object' => \%OBJECT_HANDLERS,
+ # NOTE:
+ # The sanity of enabling this feature by
+ # default is very questionable.
+ # - SL
+ #'CodeRef' => {
+ # expand => sub {}, # use eval ...
+ # collapse => sub {}, # use B::Deparse ...
+ #}
);
-sub match_type {
+sub add_custom_type_handler {
+ my ($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) = @_;
- return $TYPES{$type_constraint->name} if exists $TYPES{$type_constraint->name};
+
+ # this should handle most type usages
+ # since they they are usually just
+ # the standard set of built-ins
+ return $TYPES{$type_constraint->name}
+ if exists $TYPES{$type_constraint->name};
+
+ # the next possibility is they are
+ # a subtype of the built-in types,
+ # in which case this will DWIM in
+ # most cases. It is probably not
+ # 100% ideal though, but until I
+ # come up with a decent test case
+ # it will do for now.
foreach my $type (keys %TYPES) {
return $TYPES{$type}
if $type_constraint->is_subtype_of($type);
}
- # TODO:
- # from here we can expand this to support the following:
- # - if it is subtype of Ref
- # -- if it is a subtype of Object
- # --- treat it like an object
- # -- else
- # --- treat it like any other Ref
- # - else
- # -- if it is a subtype of Num or Str
- # --- treat it like Num or Str
- # -- else
- # --- pass it on
- # this should cover 80% of all use cases
-
- # CHRIS: To cover the last 20% we need a way
- # for people to extend this process.
-
+
+ # NOTE:
+ # the reason the above will work has to
+ # do with the fact that custom subtypes
+ # are mostly used for validation of
+ # the guts of a type, and not for some
+ # weird structural thing which would
+ # need to be accomidated by the serializer.
+ # Of course, mst or phaylon will probably
+ # do something to throw this assumption
+ # totally out the door ;)
+ # - SL
+
# NOTE:
# if this method hasnt returned by now
# then we have no been able to find a
=head1 NAME
-MooseX::Storage::Engine
-
-=head1 SYNOPSIS
+MooseX::Storage::Engine - The meta-engine to handle collapsing and expanding objects
=head1 DESCRIPTION
+No user serviceable parts inside. If you really want to know, read the source :)
+
=head1 METHODS
=head2 Accessors
=item B<storage>
+=item B<seen>
+
=back
=head2 API
=item B<expand_attribute_value>
+=item B<check_for_cycle_in_collapse>
+
+=item B<check_for_cycle_in_expansion>
+
=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