[gitmo/MooseX-Storage.git] / lib / MooseX / Storage / Engine.pm


package MooseX::Storage::Engine;
use Moose;

has 'storage' => (
    is      => 'rw',
    isa     => 'HashRef',
    default => sub {{}}
);

has 'object' => (is => 'rw', isa => '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;    
	return $self->storage;
}

sub expand_object {
    my ($self, $data) = @_;
    $self->map_attributes('expand_attribute', $data);
	return $self->storage;    
}

## this is the internal API ...

sub collapse_attribute {
    my ($self, $attr)  = @_;
    $self->storage->{$attr->name} = $self->collapse_attribute_value($attr) || return;
}

sub expand_attribute {
    my ($self, $attr, $data)  = @_;
    $self->storage->{$attr->name} = $self->expand_attribute_value($attr, $data->{$attr->name}) || return;
}

sub collapse_attribute_value {
    my ($self, $attr)  = @_;
	my $value = $attr->get_value($self->object);
    if (defined $value && $attr->has_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);
    }
	return $value;
}

sub expand_attribute_value {
    my ($self, $attr, $value)  = @_;
    if (defined $value && $attr->has_type_constraint) {
        my $type_converter = $self->find_type_handler($attr->type_constraint);
        $value = $type_converter->{expand}->($value);
    }
	return $value;
}

# util methods ...

sub map_attributes {
    my ($self, $method_name, @args) = @_;
    map { 
        $self->$method_name($_, @args) 
    } ($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__'})
            || confess "Serialized item has no class marker";
        $data->{'__class__'}->unpack($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 } },
    # 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 $array = shift;
            foreach my $i (0 .. $#{$array}) {
                next unless ref($array->[$i]) eq 'HASH' 
                         && exists $array->[$i]->{'__class__'};
                $array->[$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__'};
                $hash->{$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:
    # The sanity of enabling this feature by 
    # default is very questionable.
    # - SL
    #'CodeRef' => {
    #    expand   => sub {}, # use eval ...
    #    collapse => sub {}, # use B::Deparse ...        
    #}       
);

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
    # 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);
    }
    
    # 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 . ")";    
}

1;

__END__

=pod

=head1 NAME

MooseX::Storage::Engine

=head1 SYNOPSIS

=head1 DESCRIPTION

=head1 METHODS

=head2 Accessors

=over 4

=item B<class>

=item B<object>

=item B<storage>

=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<map_attributes>

=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

=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 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
Commit	Line	Data
e59193fb	1
	2	package MooseX::Storage::Engine;
	3	use Moose;
	4
	5	has 'storage' => (
e9739624	6	is => 'rw',
e9739624	7	isa => 'HashRef',
e59193fb	8	default => sub {{}}
	9	);
	10
e9739624	11	has 'object' => (is => 'rw', isa => 'Object');
e9739624	12	has 'class' => (is => 'rw', isa => 'Str');
e59193fb	13
e9739624	14	## this is the API used by other modules ...
e59193fb	15
	16	sub collapse_object {
	17	my $self = shift;
e9739624	18	$self->map_attributes('collapse_attribute');
e9739624	19	$self->storage->{'__class__'} = $self->object->meta->name;
e59193fb	20	return $self->storage;
	21	}
	22
e9739624	23	sub expand_object {
	24	my ($self, $data) = @_;
	25	$self->map_attributes('expand_attribute', $data);
	26	return $self->storage;
e59193fb	27	}
e59193fb	28
e9739624	29	## this is the internal API ...
	30
	31	sub collapse_attribute {
	32	my ($self, $attr) = @_;
	33	$self->storage->{$attr->name} = $self->collapse_attribute_value($attr) \|\| return;
	34	}
	35
	36	sub expand_attribute {
	37	my ($self, $attr, $data) = @_;
	38	$self->storage->{$attr->name} = $self->expand_attribute_value($attr, $data->{$attr->name}) \|\| return;
e59193fb	39	}
e59193fb	40
e9739624	41	sub collapse_attribute_value {
e59193fb	42	my ($self, $attr) = @_;
e9739624	43	my $value = $attr->get_value($self->object);
e9739624	44	if (defined $value && $attr->has_type_constraint) {
3db8f791	45	my $type_converter = $self->find_type_handler($attr->type_constraint);
e9739624	46	(defined $type_converter)
	47	\|\| confess "Cannot convert " . $attr->type_constraint->name;
	48	$value = $type_converter->{collapse}->($value);
	49	}
	50	return $value;
	51	}
	52
	53	sub expand_attribute_value {
	54	my ($self, $attr, $value) = @_;
e9739624	55	if (defined $value && $attr->has_type_constraint) {
3db8f791	56	my $type_converter = $self->find_type_handler($attr->type_constraint);
e9739624	57	$value = $type_converter->{expand}->($value);
	58	}
	59	return $value;
	60	}
	61
	62	# util methods ...
	63
	64	sub map_attributes {
	65	my ($self, $method_name, @args) = @_;
	66	map {
	67	$self->$method_name($_, @args)
	68	} ($self->object \|\| $self->class)->meta->compute_all_applicable_attributes;
e59193fb	69	}
e59193fb	70
913d96dd	71	## ------------------------------------------------------------------
3db8f791	72	## This is all the type handler stuff, it is in a state of flux
	73	## right now, so this may change, or it may just continue to be
	74	## improved upon. Comments and suggestions are welcomed.
913d96dd	75	## ------------------------------------------------------------------
	76
	77	# NOTE:
	78	# these are needed by the
	79	# ArrayRef and HashRef handlers
	80	# below, so I need easy access
	81	my %OBJECT_HANDLERS = (
	82	expand => sub {
	83	my $data = shift;
	84	(exists $data->{'__class__'})
	85	\|\| confess "Serialized item has no class marker";
	86	$data->{'__class__'}->unpack($data);
	87	},
	88	collapse => sub {
	89	my $obj = shift;
	90	($obj->can('does') && $obj->does('MooseX::Storage::Basic'))
	91	\|\| confess "Bad object ($obj) does not do MooseX::Storage::Basic role";
	92	$obj->pack();
	93	},
	94	);
	95
	96
e59193fb	97	my %TYPES = (
3db8f791	98	# These are boring ones, so they use the identity function ...
e9739624	99	'Int' => { expand => sub { shift }, collapse => sub { shift } },
	100	'Num' => { expand => sub { shift }, collapse => sub { shift } },
	101	'Str' => { expand => sub { shift }, collapse => sub { shift } },
3db8f791	102	# These are the trickier ones, (see notes)
	103	# NOTE:
	104	# Because we are nice guys, we will check
	105	# your ArrayRef and/or HashRef one level
	106	# down and inflate any objects we find.
	107	# But this is where it ends, it is too
	108	# expensive to try and do this any more
	109	# recursively, when it is probably not
	110	# nessecary in most of the use cases.
	111	# However, if you need more then this, subtype
	112	# and add a custom handler.
913d96dd	113	'ArrayRef' => {
e9739624	114	expand => sub {
913d96dd	115	my $array = shift;
	116	foreach my $i (0 .. $#{$array}) {
	117	next unless ref($array->[$i]) eq 'HASH'
	118	&& exists $array->[$i]->{'__class__'};
	119	$array->[$i] = $OBJECT_HANDLERS{expand}->($array->[$i])
	120	}
	121	$array;
	122	},
	123	collapse => sub {
	124	my $array = shift;
	125	# NOTE:
	126	# we need to make a copy cause
	127	# otherwise it will affect the
	128	# other real version.
	129	[ map {
	130	blessed($_)
	131	? $OBJECT_HANDLERS{collapse}->($_)
	132	: $_
	133	} @$array ]
	134	}
	135	},
	136	'HashRef' => {
3db8f791	137	expand => sub {
	138	my $hash = shift;
	139	foreach my $k (keys %$hash) {
	140	next unless ref($hash->{$k}) eq 'HASH'
	141	&& exists $hash->{$k}->{'__class__'};
	142	$hash->{$k} = $OBJECT_HANDLERS{expand}->($hash->{$k})
	143	}
	144	$hash;
	145	},
	146	collapse => sub {
	147	my $hash = shift;
	148	# NOTE:
	149	# we need to make a copy cause
	150	# otherwise it will affect the
	151	# other real version.
	152	+{ map {
95f31c36	153	blessed($hash->{$_})
3db8f791	154	? ($_ => $OBJECT_HANDLERS{collapse}->($hash->{$_}))
	155	: ($_ => $hash->{$_})
	156	} keys %$hash }
	157	}
e1bb45ff	158	},
913d96dd	159	'Object' => \%OBJECT_HANDLERS,
e1bb45ff	160	# NOTE:
	161	# The sanity of enabling this feature by
	162	# default is very questionable.
	163	# - SL
	164	#'CodeRef' => {
	165	# expand => sub {}, # use eval ...
	166	# collapse => sub {}, # use B::Deparse ...
	167	#}
e59193fb	168	);
e59193fb	169
3db8f791	170	sub add_custom_type_handler {
	171	my ($class, $type_name, %handlers) = @_;
	172	(exists $handlers{expand} && exists $handlers{collapse})
	173	\|\| confess "Custom type handlers need an expand and a collapse method";
	174	$TYPES{$type_name} = \%handlers;
	175	}
	176
	177	sub remove_custom_type_handler {
	178	my ($class, $type_name) = @_;
	179	delete $TYPES{$type_name} if exists $TYPES{$type_name};
	180	}
	181
	182	sub find_type_handler {
e59193fb	183	my ($self, $type_constraint) = @_;
e1bb45ff	184
	185	# this should handle most type usages
	186	# since they they are usually just
	187	# the standard set of built-ins
	188	return $TYPES{$type_constraint->name}
	189	if exists $TYPES{$type_constraint->name};
	190
	191	# the next possibility is they are
	192	# a subtype of the built-in types,
	193	# in which case this will DWIM in
	194	# most cases. It is probably not
	195	# 100% ideal though, but until I
	196	# come up with a decent test case
	197	# it will do for now.
e59193fb	198	foreach my $type (keys %TYPES) {
	199	return $TYPES{$type}
	200	if $type_constraint->is_subtype_of($type);
	201	}
e1bb45ff	202
	203	# NOTE:
	204	# the reason the above will work has to
	205	# do with the fact that custom subtypes
	206	# are mostly used for validation of
	207	# the guts of a type, and not for some
	208	# weird structural thing which would
	209	# need to be accomidated by the serializer.
	210	# Of course, mst or phaylon will probably
	211	# do something to throw this assumption
	212	# totally out the door ;)
	213	# - SL
	214
e9739624	215	# NOTE:
	216	# if this method hasnt returned by now
	217	# then we have no been able to find a
	218	# type constraint handler to match
	219	confess "Cannot handle type constraint (" . $type_constraint->name . ")";
e59193fb	220	}
	221
	222	1;
e9739624	223
	224	__END__
	225
	226	=pod
	227
ec9c1923	228	=head1 NAME
	229
	230	MooseX::Storage::Engine
	231
	232	=head1 SYNOPSIS
	233
	234	=head1 DESCRIPTION
	235
	236	=head1 METHODS
	237
	238	=head2 Accessors
	239
	240	=over 4
	241
	242	=item B<class>
	243
	244	=item B<object>
	245
	246	=item B<storage>
	247
	248	=back
	249
	250	=head2 API
	251
	252	=over 4
	253
	254	=item B<expand_object>
	255
	256	=item B<collapse_object>
	257
	258	=back
	259
	260	=head2 ...
	261
	262	=over 4
	263
	264	=item B<collapse_attribute>
	265
	266	=item B<collapse_attribute_value>
	267
	268	=item B<expand_attribute>
	269
	270	=item B<expand_attribute_value>
	271
	272	=item B<map_attributes>
	273
3db8f791	274	=back
	275
	276	=head2 Type Constraint Handlers
	277
	278	=over 4
	279
	280	=item B<find_type_handler>
	281
	282	=item B<add_custom_type_handler>
	283
	284	=item B<remove_custom_type_handler>
ec9c1923	285
	286	=back
	287
	288	=head2 Introspection
	289
	290	=over 4
	291
	292	=item B<meta>
	293
	294	=back
	295
	296	=head1 BUGS
	297
	298	All complex software has bugs lurking in it, and this module is no
	299	exception. If you find a bug please either email me, or add the bug
	300	to cpan-RT.
	301
	302	=head1 AUTHOR
	303
	304	Chris Prather E<lt>chris.prather@iinteractive.comE<gt>
	305
	306	Stevan Little E<lt>stevan.little@iinteractive.comE<gt>
	307
	308	=head1 COPYRIGHT AND LICENSE
	309
	310	Copyright 2007 by Infinity Interactive, Inc.
	311
	312	L<http://www.iinteractive.com>
	313
	314	This library is free software; you can redistribute it and/or modify
	315	it under the same terms as Perl itself.
	316
e9739624	317	=cut
	318
	319
ec9c1923	320