package MooseX::Storage::Engine;
use Moose;
+use Scalar::Util qw(refaddr);
+
+our $VERSION = '0.32';
+our $AUTHORITY = 'cpan:STEVAN';
+
+# the class marker when
+# serializing an object.
+our $CLASS_MARKER = '__CLASS__';
has 'storage' => (
- is => 'rw',
+ is => 'ro',
isa => 'HashRef',
default => sub {{}}
);
-has 'object' => (is => 'rw', isa => 'Object');
+has 'seen' => (
+ is => 'ro',
+ isa => 'HashRef[Int]', # int is the refaddr
+ default => sub {{}}
+);
+
+has 'object' => (is => 'rw', isa => 'Object', predicate => '_has_object');
has 'class' => (is => 'rw', isa => 'Str');
## this is the API used by other modules ...
sub collapse_object {
- my $self = shift;
- $self->map_attributes('collapse_attribute');
- $self->storage->{'__class__'} = $self->object->meta->name;
+ my ( $self, %options ) = @_;
+
+ # NOTE:
+ # mark the root object as seen ...
+ $self->seen->{refaddr $self->object} = undef;
+
+ $self->map_attributes('collapse_attribute', \%options);
+ $self->storage->{$CLASS_MARKER} = $self->object->meta->identifier;
return $self->storage;
}
sub expand_object {
- my ($self, $data) = @_;
- $self->map_attributes('expand_attribute', $data);
- return $self->storage;
+ my ($self, $data, %options) = @_;
+
+ $options{check_version} = 1 unless exists $options{check_version};
+ $options{check_authority} = 1 unless exists $options{check_authority};
+
+ # NOTE:
+ # mark the root object as seen ...
+ $self->seen->{refaddr $data} = undef;
+
+ $self->map_attributes('expand_attribute', $data, \%options);
+ return $self->storage;
}
## this is the internal API ...
sub collapse_attribute {
- my ($self, $attr) = @_;
- $self->storage->{$attr->name} = $self->collapse_attribute_value($attr) || return;
+ my ($self, $attr, $options) = @_;
+ my $value = $self->collapse_attribute_value($attr, $options);
+ return if !defined($value);
+ $self->storage->{$attr->name} = $value;
}
sub expand_attribute {
- my ($self, $attr, $data) = @_;
- $self->storage->{$attr->name} = $self->expand_attribute_value($attr, $data->{$attr->name}) || return;
+ my ($self, $attr, $data, $options) = @_;
+ my $value = $self->expand_attribute_value($attr, $data->{$attr->name}, $options);
+ $self->storage->{$attr->name} = defined $value ? $value : return;
}
sub collapse_attribute_value {
- my ($self, $attr) = @_;
+ my ($self, $attr, $options) = @_;
+ # Faster, but breaks attributes without readers, do we care?
+ #my $value = $attr->get_read_method_ref->($self->object);
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, $value);
(defined $type_converter)
|| confess "Cannot convert " . $attr->type_constraint->name;
- $value = $type_converter->{collapse}->($value);
+ $value = $type_converter->{collapse}->($value, $options);
}
return $value;
}
sub expand_attribute_value {
- my ($self, $attr, $value) = @_;
- # TODO:
- # we need to check $value here to
- # make sure that we do not have
- # a cycle here.
+ my ($self, $attr, $value, $options) = @_;
+
+ # NOTE:
+ # (see comment in method above ^^)
+ if( ref $value and not(
+ $options->{disable_cycle_check} or
+ $self->class->does('MooseX::Storage::Traits::DisableCycleDetection')
+ )) {
+ $self->check_for_cycle_in_collapse($attr, $value)
+ }
+
if (defined $value && $attr->has_type_constraint) {
- my $type_converter = $self->match_type($attr->type_constraint);
- $value = $type_converter->{expand}->($value);
+ my $type_converter = $self->find_type_handler($attr->type_constraint, $value);
+ $value = $type_converter->{expand}->($value, $options);
}
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->{refaddr $value})
+ || confess "Basic Engine does not support cycles in class("
+ . ($attr->associated_class->name) . ").attr("
+ . ($attr->name) . ") with $value";
+ $self->seen->{refaddr $value} = undef;
+}
+
+sub check_for_cycle_in_expansion {
+ my ($self, $attr, $value) = @_;
+ (!exists $self->seen->{refaddr $value})
+ || confess "Basic Engine does not support cycles in class("
+ . ($attr->associated_class->name) . ").attr("
+ . ($attr->name) . ") with $value";
+ $self->seen->{refaddr $value} = undef;
+}
+
# util methods ...
sub map_attributes {
my ($self, $method_name, @args) = @_;
- map {
- $self->$method_name($_, @args)
- } ($self->object || $self->class)->meta->compute_all_applicable_attributes;
+ map {
+ $self->$method_name($_, @args)
+ } grep {
+ # Skip our special skip attribute :)
+ !$_->does('MooseX::Storage::Meta::Attribute::Trait::DoNotSerialize')
+ } ($self->_has_object ? $self->object : $self->class)->meta->get_all_attributes;
}
+## ------------------------------------------------------------------
+## This is all the type handler stuff, it is in a state of flux
+## right now, so this may change, or it may just continue to be
+## improved upon. Comments and suggestions are welcomed.
+## ------------------------------------------------------------------
+
+# NOTE:
+# these are needed by the
+# ArrayRef and HashRef handlers
+# below, so I need easy access
+my %OBJECT_HANDLERS = (
+ expand => sub {
+ my ($data, $options) = @_;
+ (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 $@;
+
+ if ($options->{check_version}) {
+ my $meta_version = $meta->version;
+ if (defined $meta_version && $version) {
+ if ($options->{check_version} eq 'allow_less_than') {
+ ($meta_version <= $version)
+ || confess "Class ($class) versions is not less than currently available."
+ . " got=($version) available=($meta_version)";
+ }
+ elsif ($options->{check_version} eq 'allow_greater_than') {
+ ($meta->version >= $version)
+ || confess "Class ($class) versions is not greater than currently available."
+ . " got=($version) available=($meta_version)";
+ }
+ else {
+ ($meta->version == $version)
+ || confess "Class ($class) versions don't match."
+ . " got=($version) available=($meta_version)";
+ }
+ }
+ }
+
+ if ($options->{check_authority}) {
+ my $meta_authority = $meta->authority;
+ ($meta->authority eq $authority)
+ || confess "Class ($class) authorities don't match."
+ . " got=($authority) available=($meta_authority)"
+ if defined $meta_authority && defined $authority;
+ }
+
+ # all is well ...
+ $class->unpack($data, %$options);
+ },
+ collapse => sub {
+ my ( $obj, $options ) = @_;
+# ($obj->can('does') && $obj->does('MooseX::Storage::Basic'))
+# || confess "Bad object ($obj) does not do MooseX::Storage::Basic role";
+ ($obj->can('pack'))
+ || confess "Object ($obj) does not have a &pack method, cannot collapse";
+ $obj->pack(%$options);
+ },
+);
+
+
my %TYPES = (
- 'Int' => { expand => sub { shift }, collapse => sub { shift } },
- 'Num' => { expand => sub { shift }, collapse => sub { shift } },
+ # NOTE:
+ # we need to make sure that we properly numify the numbers
+ # before and after them being futzed with, because some of
+ # the JSON engines are stupid/annoying/frustrating
+ 'Int' => { expand => sub { $_[0] + 0 }, collapse => sub { $_[0] + 0 } },
+ 'Num' => { expand => sub { $_[0] + 0 }, collapse => sub { $_[0] + 0 } },
+ # These are boring ones, so they use the identity function ...
'Str' => { expand => sub { shift }, collapse => sub { shift } },
- 'ArrayRef' => { expand => sub { shift }, collapse => sub { shift } },
- 'HashRef' => { expand => sub { shift }, collapse => sub { shift } },
- 'Object' => {
+ 'Bool' => { 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' => {
expand => sub {
- my $data = shift;
- (exists $data->{'__class__'})
- || confess "Serialized item has no class marker";
- $data->{'__class__'}->unpack($data);
+ my ( $array, @args ) = @_;
+ foreach my $i (0 .. $#{$array}) {
+ next unless ref($array->[$i]) eq 'HASH'
+ && exists $array->[$i]->{$CLASS_MARKER};
+ $array->[$i] = $OBJECT_HANDLERS{expand}->($array->[$i], @args);
+ }
+ $array;
},
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 ( $array, @args ) = @_;
+ # NOTE:
+ # we need to make a copy cause
+ # otherwise it will affect the
+ # other real version.
+ [ map {
+ blessed($_)
+ ? $OBJECT_HANDLERS{collapse}->($_, @args)
+ : $_
+ } @$array ]
+ }
+ },
+ 'HashRef' => {
+ expand => sub {
+ my ( $hash, @args ) = @_;
+ foreach my $k (keys %$hash) {
+ next unless ref($hash->{$k}) eq 'HASH'
+ && exists $hash->{$k}->{$CLASS_MARKER};
+ $hash->{$k} = $OBJECT_HANDLERS{expand}->($hash->{$k}, @args);
+ }
+ $hash;
},
- }
+ collapse => sub {
+ my ( $hash, @args ) = @_;
+ # NOTE:
+ # we need to make a copy cause
+ # otherwise it will affect the
+ # other real version.
+ +{ map {
+ blessed($hash->{$_})
+ ? ($_ => $OBJECT_HANDLERS{collapse}->($hash->{$_}, @args))
+ : ($_ => $hash->{$_})
+ } keys %$hash }
+ }
+ },
+ 'Object' => \%OBJECT_HANDLERS,
+ # NOTE:
+ # The sanity of enabling this feature by
+ # default is very questionable.
+ # - SL
+ #'CodeRef' => {
+ # expand => sub {}, # use eval ...
+ # collapse => sub {}, # use B::Deparse ...
+ #}
);
-sub match_type {
- my ($self, $type_constraint) = @_;
- return $TYPES{$type_constraint->name} if exists $TYPES{$type_constraint->name};
+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, $value) = @_;
+
+ # check if the type is a Maybe and
+ # if its parent is not parameterized.
+ # If both is true recurse this method
+ # using ->type_parameter.
+ return $self->find_type_handler($type_constraint->type_parameter, $value)
+ if ($type_constraint->parent && $type_constraint->parent eq 'Maybe'
+ and not $type_constraint->parent->can('type_parameter'));
+
+ # find_type_for is a method of a union type. If we can call that method
+ # then we are dealign with a union and we need to ascertain which of
+ # the union's types we need to use for the value we are serializing.
+ if($type_constraint->can('find_type_for')) {
+ my $tc = $type_constraint->find_type_for($value);
+ return $self->find_type_handler($tc, $value) if defined($tc);
+ }
+
+ # 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}
+ 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
- # type constraint handler to match
- confess "Cannot handle type constraint (" . $type_constraint->name . ")";
+ # then we have no been able to find a
+ # type constraint handler to match
+ confess "Cannot handle type constraint (" . $type_constraint->name . ")";
}
+sub find_type_handler_for {
+ my ($self, $type_handler_name) = @_;
+ $TYPES{$type_handler_name}
+}
+
+no Moose::Role;
+
1;
__END__
=pod
+=head1 NAME
+
+MooseX::Storage::Engine - The meta-engine to handle collapsing and expanding objects
+
+=head1 DESCRIPTION
+
+There really aren't any major user serviceable parts here. However the typical
+use case is adding new non-Moose classes to the type registry for
+serialization. Here is an example of this for DateTime objects. This
+assumes a C<DateTime> type has been registered.
+
+ MooseX::Storage::Engine->add_custom_type_handler(
+ 'DateTime' => (
+ expand => sub { DateTime->new(shift) },
+ collapse => sub { (shift)->iso8601 },
+ )
+ );
+
+=head1 METHODS
+
+=head2 Accessors
+
+=over 4
+
+=item B<class>
+
+=item B<object>
+
+=item B<storage>
+
+=item B<seen>
+
+=back
+
+=head2 API
+
+=over 4
+
+=item B<expand_object>
+
+=item B<collapse_object>
+
+=back
+
+=head2 ...
+
+=over 4
+
+=item B<collapse_attribute>
+
+=item B<collapse_attribute_value>
+
+=item B<expand_attribute>
+
+=item B<expand_attribute_value>
+
+=item B<check_for_cycle_in_collapse>
+
+=item B<check_for_cycle_in_expansion>
+
+=item B<map_attributes>
+
+=back
+
+=head2 Type Constraint Handlers
+
+=over 4
+
+=item B<find_type_handler ($type)>
+
+=item B<find_type_handler_for ($name)>
+
+=item B<add_custom_type_handler ($name, %handlers)>
+
+=item B<remove_custom_type_handler ($name)>
+
+=back
+
+=head2 Introspection
+
+=over 4
+
+=item B<meta>
+
+=back
+
+=head1 BUGS
+
+All complex software has bugs lurking in it, and this module is no
+exception. If you find a bug please either email me, or add the bug
+to cpan-RT.
+
+=head1 AUTHOR
+
+Chris Prather E<lt>chris.prather@iinteractive.comE<gt>
+
+Stevan Little E<lt>stevan.little@iinteractive.comE<gt>
+
+=head1 COPYRIGHT AND LICENSE
+
+Copyright 2007-2008 by Infinity Interactive, Inc.
+
+L<http://www.iinteractive.com>
+
+This library is free software; you can redistribute it and/or modify
+it under the same terms as Perl itself.
+
=cut
+
projects / gitmo/MooseX-Storage.git / blobdiff