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1 | |
2 | package MooseX::Storage::Engine; |
3 | use Moose; |
4 | |
45d9a73c |
5 | our $VERSION = '0.02'; |
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6 | |
7 | # the class marker when |
8 | # serializing an object. |
9 | our $CLASS_MARKER = '__CLASS__'; |
10 | |
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11 | has 'storage' => ( |
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12 | is => 'ro', |
13 | isa => 'HashRef', |
14 | default => sub {{}} |
15 | ); |
16 | |
17 | has 'seen' => ( |
18 | is => 'ro', |
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19 | isa => 'HashRef', |
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20 | default => sub {{}} |
21 | ); |
22 | |
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23 | has 'object' => (is => 'rw', isa => 'Object'); |
24 | has 'class' => (is => 'rw', isa => 'Str'); |
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25 | |
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26 | ## this is the API used by other modules ... |
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27 | |
28 | sub collapse_object { |
29 | my $self = shift; |
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30 | |
31 | # NOTE: |
32 | # mark the root object as seen ... |
33 | $self->seen->{$self->object} = undef; |
34 | |
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35 | $self->map_attributes('collapse_attribute'); |
ba5bba75 |
36 | $self->storage->{$CLASS_MARKER} = $self->object->meta->name; |
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37 | return $self->storage; |
38 | } |
39 | |
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40 | sub expand_object { |
41 | my ($self, $data) = @_; |
7eb5dc63 |
42 | |
43 | # NOTE: |
44 | # mark the root object as seen ... |
45 | $self->seen->{$data} = undef; |
46 | |
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47 | $self->map_attributes('expand_attribute', $data); |
48 | return $self->storage; |
e59193fb |
49 | } |
50 | |
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51 | ## this is the internal API ... |
52 | |
53 | sub collapse_attribute { |
54 | my ($self, $attr) = @_; |
55 | $self->storage->{$attr->name} = $self->collapse_attribute_value($attr) || return; |
56 | } |
57 | |
58 | sub expand_attribute { |
59 | my ($self, $attr, $data) = @_; |
60 | $self->storage->{$attr->name} = $self->expand_attribute_value($attr, $data->{$attr->name}) || return; |
e59193fb |
61 | } |
62 | |
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63 | sub collapse_attribute_value { |
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64 | my ($self, $attr) = @_; |
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65 | my $value = $attr->get_value($self->object); |
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66 | |
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67 | # NOTE: |
68 | # this might not be enough, we might |
69 | # need to make it possible for the |
70 | # cycle checker to return the value |
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71 | $self->check_for_cycle_in_collapse($attr, $value) |
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72 | if ref $value; |
73 | |
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74 | if (defined $value && $attr->has_type_constraint) { |
3db8f791 |
75 | my $type_converter = $self->find_type_handler($attr->type_constraint); |
e9739624 |
76 | (defined $type_converter) |
77 | || confess "Cannot convert " . $attr->type_constraint->name; |
78 | $value = $type_converter->{collapse}->($value); |
79 | } |
80 | return $value; |
81 | } |
82 | |
83 | sub expand_attribute_value { |
84 | my ($self, $attr, $value) = @_; |
7eb5dc63 |
85 | |
b430caa3 |
86 | # NOTE: |
87 | # (see comment in method above ^^) |
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88 | $self->check_for_cycle_in_expansion($attr, $value) |
7eb5dc63 |
89 | if ref $value; |
90 | |
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91 | if (defined $value && $attr->has_type_constraint) { |
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92 | my $type_converter = $self->find_type_handler($attr->type_constraint); |
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93 | $value = $type_converter->{expand}->($value); |
94 | } |
95 | return $value; |
96 | } |
97 | |
b430caa3 |
98 | # NOTE: |
99 | # possibly these two methods will |
100 | # be used by a cycle supporting |
101 | # engine. However, I am not sure |
102 | # if I can make a cycle one work |
103 | # anyway. |
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104 | |
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105 | sub check_for_cycle_in_collapse { |
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106 | my ($self, $attr, $value) = @_; |
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107 | (!exists $self->seen->{$value}) |
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108 | || confess "Basic Engine does not support cycles in class(" |
109 | . ($attr->associated_metaclass->name) . ").attr(" |
110 | . ($attr->name) . ") with $value"; |
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111 | $self->seen->{$value} = undef; |
112 | } |
113 | |
114 | sub check_for_cycle_in_expansion { |
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115 | my ($self, $attr, $value) = @_; |
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116 | (!exists $self->seen->{$value}) |
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117 | || confess "Basic Engine does not support cycles in class(" |
118 | . ($attr->associated_metaclass->name) . ").attr(" |
119 | . ($attr->name) . ") with $value"; |
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120 | $self->seen->{$value} = undef; |
121 | } |
122 | |
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123 | # util methods ... |
124 | |
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125 | sub map_attributes { |
126 | my ($self, $method_name, @args) = @_; |
127 | map { |
128 | $self->$method_name($_, @args) |
b430caa3 |
129 | } grep { |
130 | # Skip our special skip attribute :) |
131 | !$_->isa('MooseX::Storage::Meta::Attribute::DoNotSerialize') |
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132 | } ($self->object || $self->class)->meta->compute_all_applicable_attributes; |
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133 | } |
134 | |
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135 | ## ------------------------------------------------------------------ |
3db8f791 |
136 | ## This is all the type handler stuff, it is in a state of flux |
137 | ## right now, so this may change, or it may just continue to be |
138 | ## improved upon. Comments and suggestions are welcomed. |
913d96dd |
139 | ## ------------------------------------------------------------------ |
140 | |
141 | # NOTE: |
142 | # these are needed by the |
143 | # ArrayRef and HashRef handlers |
144 | # below, so I need easy access |
145 | my %OBJECT_HANDLERS = ( |
146 | expand => sub { |
147 | my $data = shift; |
ba5bba75 |
148 | (exists $data->{$CLASS_MARKER}) |
913d96dd |
149 | || confess "Serialized item has no class marker"; |
ba5bba75 |
150 | $data->{$CLASS_MARKER}->unpack($data); |
913d96dd |
151 | }, |
152 | collapse => sub { |
153 | my $obj = shift; |
154 | ($obj->can('does') && $obj->does('MooseX::Storage::Basic')) |
155 | || confess "Bad object ($obj) does not do MooseX::Storage::Basic role"; |
156 | $obj->pack(); |
157 | }, |
158 | ); |
159 | |
160 | |
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161 | my %TYPES = ( |
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162 | # These are boring ones, so they use the identity function ... |
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163 | 'Int' => { expand => sub { shift }, collapse => sub { shift } }, |
164 | 'Num' => { expand => sub { shift }, collapse => sub { shift } }, |
165 | 'Str' => { expand => sub { shift }, collapse => sub { shift } }, |
3db8f791 |
166 | # These are the trickier ones, (see notes) |
167 | # NOTE: |
168 | # Because we are nice guys, we will check |
169 | # your ArrayRef and/or HashRef one level |
170 | # down and inflate any objects we find. |
171 | # But this is where it ends, it is too |
172 | # expensive to try and do this any more |
173 | # recursively, when it is probably not |
174 | # nessecary in most of the use cases. |
175 | # However, if you need more then this, subtype |
176 | # and add a custom handler. |
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177 | 'ArrayRef' => { |
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178 | expand => sub { |
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179 | my $array = shift; |
180 | foreach my $i (0 .. $#{$array}) { |
181 | next unless ref($array->[$i]) eq 'HASH' |
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182 | && exists $array->[$i]->{$CLASS_MARKER}; |
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183 | $array->[$i] = $OBJECT_HANDLERS{expand}->($array->[$i]) |
184 | } |
185 | $array; |
186 | }, |
187 | collapse => sub { |
188 | my $array = shift; |
189 | # NOTE: |
190 | # we need to make a copy cause |
191 | # otherwise it will affect the |
192 | # other real version. |
193 | [ map { |
194 | blessed($_) |
195 | ? $OBJECT_HANDLERS{collapse}->($_) |
196 | : $_ |
197 | } @$array ] |
198 | } |
199 | }, |
200 | 'HashRef' => { |
3db8f791 |
201 | expand => sub { |
202 | my $hash = shift; |
203 | foreach my $k (keys %$hash) { |
204 | next unless ref($hash->{$k}) eq 'HASH' |
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205 | && exists $hash->{$k}->{$CLASS_MARKER}; |
3db8f791 |
206 | $hash->{$k} = $OBJECT_HANDLERS{expand}->($hash->{$k}) |
207 | } |
208 | $hash; |
209 | }, |
210 | collapse => sub { |
211 | my $hash = shift; |
212 | # NOTE: |
213 | # we need to make a copy cause |
214 | # otherwise it will affect the |
215 | # other real version. |
216 | +{ map { |
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217 | blessed($hash->{$_}) |
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218 | ? ($_ => $OBJECT_HANDLERS{collapse}->($hash->{$_})) |
219 | : ($_ => $hash->{$_}) |
220 | } keys %$hash } |
221 | } |
e1bb45ff |
222 | }, |
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223 | 'Object' => \%OBJECT_HANDLERS, |
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224 | # NOTE: |
225 | # The sanity of enabling this feature by |
226 | # default is very questionable. |
227 | # - SL |
228 | #'CodeRef' => { |
229 | # expand => sub {}, # use eval ... |
230 | # collapse => sub {}, # use B::Deparse ... |
7eb5dc63 |
231 | #} |
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232 | ); |
233 | |
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234 | sub add_custom_type_handler { |
235 | my ($class, $type_name, %handlers) = @_; |
236 | (exists $handlers{expand} && exists $handlers{collapse}) |
237 | || confess "Custom type handlers need an expand *and* a collapse method"; |
238 | $TYPES{$type_name} = \%handlers; |
239 | } |
240 | |
241 | sub remove_custom_type_handler { |
242 | my ($class, $type_name) = @_; |
243 | delete $TYPES{$type_name} if exists $TYPES{$type_name}; |
244 | } |
245 | |
246 | sub find_type_handler { |
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247 | my ($self, $type_constraint) = @_; |
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248 | |
249 | # this should handle most type usages |
250 | # since they they are usually just |
251 | # the standard set of built-ins |
252 | return $TYPES{$type_constraint->name} |
253 | if exists $TYPES{$type_constraint->name}; |
254 | |
255 | # the next possibility is they are |
256 | # a subtype of the built-in types, |
257 | # in which case this will DWIM in |
258 | # most cases. It is probably not |
259 | # 100% ideal though, but until I |
260 | # come up with a decent test case |
261 | # it will do for now. |
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262 | foreach my $type (keys %TYPES) { |
263 | return $TYPES{$type} |
264 | if $type_constraint->is_subtype_of($type); |
265 | } |
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266 | |
267 | # NOTE: |
268 | # the reason the above will work has to |
269 | # do with the fact that custom subtypes |
270 | # are mostly used for validation of |
271 | # the guts of a type, and not for some |
272 | # weird structural thing which would |
273 | # need to be accomidated by the serializer. |
274 | # Of course, mst or phaylon will probably |
275 | # do something to throw this assumption |
276 | # totally out the door ;) |
277 | # - SL |
278 | |
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279 | # NOTE: |
280 | # if this method hasnt returned by now |
281 | # then we have no been able to find a |
282 | # type constraint handler to match |
283 | confess "Cannot handle type constraint (" . $type_constraint->name . ")"; |
e59193fb |
284 | } |
285 | |
286 | 1; |
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287 | |
288 | __END__ |
289 | |
290 | =pod |
291 | |
ec9c1923 |
292 | =head1 NAME |
293 | |
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294 | MooseX::Storage::Engine - The meta-engine to handle collapsing and expanding objects |
ec9c1923 |
295 | |
296 | =head1 DESCRIPTION |
297 | |
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298 | No user serviceable parts inside. If you really want to know, read the source :) |
299 | |
ec9c1923 |
300 | =head1 METHODS |
301 | |
302 | =head2 Accessors |
303 | |
304 | =over 4 |
305 | |
306 | =item B<class> |
307 | |
308 | =item B<object> |
309 | |
310 | =item B<storage> |
311 | |
b430caa3 |
312 | =item B<seen> |
313 | |
ec9c1923 |
314 | =back |
315 | |
316 | =head2 API |
317 | |
318 | =over 4 |
319 | |
320 | =item B<expand_object> |
321 | |
322 | =item B<collapse_object> |
323 | |
324 | =back |
325 | |
326 | =head2 ... |
327 | |
328 | =over 4 |
329 | |
330 | =item B<collapse_attribute> |
331 | |
332 | =item B<collapse_attribute_value> |
333 | |
334 | =item B<expand_attribute> |
335 | |
336 | =item B<expand_attribute_value> |
337 | |
b430caa3 |
338 | =item B<check_for_cycle_in_collapse> |
339 | |
340 | =item B<check_for_cycle_in_expansion> |
341 | |
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342 | =item B<map_attributes> |
343 | |
3db8f791 |
344 | =back |
345 | |
346 | =head2 Type Constraint Handlers |
347 | |
348 | =over 4 |
349 | |
350 | =item B<find_type_handler> |
351 | |
352 | =item B<add_custom_type_handler> |
353 | |
354 | =item B<remove_custom_type_handler> |
ec9c1923 |
355 | |
356 | =back |
357 | |
358 | =head2 Introspection |
359 | |
360 | =over 4 |
361 | |
362 | =item B<meta> |
363 | |
364 | =back |
365 | |
366 | =head1 BUGS |
367 | |
368 | All complex software has bugs lurking in it, and this module is no |
369 | exception. If you find a bug please either email me, or add the bug |
370 | to cpan-RT. |
371 | |
372 | =head1 AUTHOR |
373 | |
374 | Chris Prather E<lt>chris.prather@iinteractive.comE<gt> |
375 | |
376 | Stevan Little E<lt>stevan.little@iinteractive.comE<gt> |
377 | |
378 | =head1 COPYRIGHT AND LICENSE |
379 | |
380 | Copyright 2007 by Infinity Interactive, Inc. |
381 | |
382 | L<http://www.iinteractive.com> |
383 | |
384 | This library is free software; you can redistribute it and/or modify |
385 | it under the same terms as Perl itself. |
386 | |
e9739624 |
387 | =cut |
388 | |
389 | |
ec9c1923 |
390 | |