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1 | package Moose::Exporter; |
2 | |
3 | use strict; |
4 | use warnings; |
5 | |
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6 | use Class::MOP; |
7 | use List::MoreUtils qw( first_index uniq ); |
8 | use Moose::Util::MetaRole; |
9 | use Sub::Exporter; |
10 | |
11 | |
12 | my %EXPORT_SPEC; |
13 | |
14 | sub setup_import_methods { |
15 | my ( $class, %args ) = @_; |
16 | |
17 | my $exporting_package = $args{exporting_package} ||= caller(); |
18 | |
19 | my ( $import, $unimport ) = $class->build_import_methods(%args); |
20 | |
21 | no strict 'refs'; |
22 | *{ $exporting_package . '::import' } = $import; |
23 | *{ $exporting_package . '::unimport' } = $unimport; |
24 | } |
25 | |
26 | sub build_import_methods { |
27 | my ( $class, %args ) = @_; |
28 | |
29 | my $exporting_package = $args{exporting_package} ||= caller(); |
30 | |
31 | $EXPORT_SPEC{$exporting_package} = \%args; |
32 | |
33 | my @exports_from = $class->_follow_also( $exporting_package ); |
34 | |
35 | my $export_recorder = {}; |
36 | |
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37 | my ( $exports, $is_removable ) |
38 | = $class->_make_sub_exporter_params( |
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39 | [ $exporting_package, @exports_from ], $export_recorder ); |
40 | |
41 | my $exporter = Sub::Exporter::build_exporter( |
42 | { |
43 | exports => $exports, |
44 | groups => { default => [':all'] } |
45 | } |
46 | ); |
47 | |
48 | # $args{_export_to_main} exists for backwards compat, because |
49 | # Moose::Util::TypeConstraints did export to main (unlike Moose & |
50 | # Moose::Role). |
51 | my $import = $class->_make_import_sub( $exporting_package, $exporter, |
52 | \@exports_from, $args{_export_to_main} ); |
53 | |
54 | my $unimport = $class->_make_unimport_sub( $exporting_package, $exports, |
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55 | $is_removable, $export_recorder ); |
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56 | |
57 | return ( $import, $unimport ) |
58 | } |
59 | |
60 | { |
61 | my $seen = {}; |
62 | |
63 | sub _follow_also { |
64 | my $class = shift; |
65 | my $exporting_package = shift; |
66 | |
67 | local %$seen = ( $exporting_package => 1 ); |
68 | |
69 | return uniq( _follow_also_real($exporting_package) ); |
70 | } |
71 | |
72 | sub _follow_also_real { |
73 | my $exporting_package = shift; |
74 | |
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75 | die "Package in also ($exporting_package) does not seem to use Moose::Exporter" |
e606ae5f |
76 | unless exists $EXPORT_SPEC{$exporting_package}; |
77 | |
78 | my $also = $EXPORT_SPEC{$exporting_package}{also}; |
79 | |
80 | return unless defined $also; |
81 | |
82 | my @also = ref $also ? @{$also} : $also; |
83 | |
84 | for my $package (@also) |
85 | { |
f5d03831 |
86 | die "Circular reference in also parameter to Moose::Exporter between $exporting_package and $package" |
e606ae5f |
87 | if $seen->{$package}; |
88 | |
89 | $seen->{$package} = 1; |
90 | } |
91 | |
92 | return @also, map { _follow_also_real($_) } @also; |
93 | } |
94 | } |
95 | |
96 | sub _make_sub_exporter_params { |
97 | my $class = shift; |
98 | my $packages = shift; |
99 | my $export_recorder = shift; |
100 | |
101 | my %exports; |
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102 | my %is_removable; |
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103 | |
104 | for my $package ( @{$packages} ) { |
105 | my $args = $EXPORT_SPEC{$package} |
106 | or die "The $package package does not use Moose::Exporter\n"; |
107 | |
108 | for my $name ( @{ $args->{with_caller} } ) { |
109 | my $sub = do { |
110 | no strict 'refs'; |
111 | \&{ $package . '::' . $name }; |
112 | }; |
113 | |
114 | my $fq_name = $package . '::' . $name; |
115 | |
116 | $exports{$name} = $class->_make_wrapped_sub( |
117 | $fq_name, |
118 | $sub, |
119 | $export_recorder, |
120 | ); |
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121 | |
122 | $is_removable{$name} = 1; |
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123 | } |
124 | |
125 | for my $name ( @{ $args->{as_is} } ) { |
126 | my $sub; |
127 | |
128 | if ( ref $name ) { |
129 | $sub = $name; |
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130 | |
131 | # Even though Moose re-exports things from Carp & |
132 | # Scalar::Util, we don't want to remove those at |
133 | # unimport time, because the importing package may |
134 | # have imported them explicitly ala |
135 | # |
136 | # use Carp qw( confess ); |
137 | # |
138 | # This is a hack. Since we can't know whether they |
139 | # really want to keep these subs or not, we err on the |
140 | # safe side and leave them in. |
141 | my $coderef_pkg; |
142 | ( $coderef_pkg, $name ) = Class::MOP::get_code_info($name); |
143 | |
144 | $is_removable{$name} = $coderef_pkg eq $package ? 1 : 0; |
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145 | } |
146 | else { |
147 | $sub = do { |
148 | no strict 'refs'; |
149 | \&{ $package . '::' . $name }; |
150 | }; |
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151 | |
152 | $is_removable{$name} = 1; |
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153 | } |
154 | |
155 | $export_recorder->{$sub} = 1; |
156 | |
157 | $exports{$name} = sub {$sub}; |
158 | } |
159 | } |
160 | |
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161 | return ( \%exports, \%is_removable ); |
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162 | } |
163 | |
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164 | our $CALLER; |
165 | |
166 | sub _make_wrapped_sub { |
167 | shift; |
168 | my $fq_name = shift; |
169 | my $sub = shift; |
170 | my $export_recorder = shift; |
171 | |
172 | # We need to set the package at import time, so that when |
173 | # package Foo imports has(), we capture "Foo" as the |
174 | # package. This lets other packages call Foo::has() and get |
175 | # the right package. This is done for backwards compatibility |
176 | # with existing production code, not because this is a good |
177 | # idea ;) |
178 | return sub { |
179 | my $caller = $CALLER; |
180 | |
181 | my $sub |
182 | = Class::MOP::subname( $fq_name => sub { $sub->( $caller, @_ ) } ); |
183 | |
184 | $export_recorder->{$sub} = 1; |
185 | |
186 | return $sub; |
187 | }; |
188 | } |
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189 | |
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190 | sub _make_import_sub { |
191 | shift; |
192 | my $exporting_package = shift; |
193 | my $exporter = shift; |
194 | my $exports_from = shift; |
195 | my $export_to_main = shift; |
196 | |
197 | return sub { |
198 | |
199 | # I think we could use Sub::Exporter's collector feature |
200 | # to do this, but that would be rather gross, since that |
201 | # feature isn't really designed to return a value to the |
202 | # caller of the exporter sub. |
203 | # |
204 | # Also, this makes sure we preserve backwards compat for |
205 | # _get_caller, so it always sees the arguments in the |
206 | # expected order. |
207 | my $traits; |
208 | ( $traits, @_ ) = _strip_traits(@_); |
209 | |
210 | # Normally we could look at $_[0], but in some weird cases |
211 | # (involving goto &Moose::import), $_[0] ends as something |
212 | # else (like Squirrel). |
213 | my $class = $exporting_package; |
214 | |
215 | $CALLER = _get_caller(@_); |
216 | |
217 | # this works because both pragmas set $^H (see perldoc |
218 | # perlvar) which affects the current compilation - |
219 | # i.e. the file who use'd us - which is why we don't need |
220 | # to do anything special to make it affect that file |
221 | # rather than this one (which is already compiled) |
222 | |
223 | strict->import; |
224 | warnings->import; |
225 | |
226 | # we should never export to main |
227 | if ( $CALLER eq 'main' && !$export_to_main ) { |
228 | warn |
229 | qq{$class does not export its sugar to the 'main' package.\n}; |
230 | return; |
231 | } |
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232 | |
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233 | my $did_init_meta; |
234 | for my $c ( grep { $_->can('init_meta') } $class, @{$exports_from} ) { |
235 | $c->init_meta( for_class => $CALLER ); |
236 | $did_init_meta = 1; |
237 | } |
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238 | |
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239 | if ( $did_init_meta && @{$traits} ) { |
240 | # The traits will use Moose::Role, which in turn uses |
241 | # Moose::Exporter, which in turn sets $CALLER, so we need |
242 | # to protect against that. |
243 | local $CALLER = $CALLER; |
244 | _apply_meta_traits( $CALLER, $traits ); |
245 | } |
246 | elsif ( @{$traits} ) { |
247 | Moose->throw_error( |
248 | "Cannot provide traits when $class does not have an init_meta() method" |
249 | ); |
250 | } |
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251 | |
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252 | goto $exporter; |
253 | }; |
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254 | } |
255 | |
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256 | |
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257 | sub _strip_traits { |
258 | my $idx = first_index { $_ eq '-traits' } @_; |
259 | |
260 | return ( [], @_ ) unless $idx >= 0 && $#_ >= $idx + 1; |
261 | |
262 | my $traits = $_[ $idx + 1 ]; |
263 | |
264 | splice @_, $idx, 2; |
265 | |
266 | $traits = [ $traits ] unless ref $traits; |
267 | |
268 | return ( $traits, @_ ); |
269 | } |
270 | |
271 | sub _apply_meta_traits { |
272 | my ( $class, $traits ) = @_; |
273 | |
274 | return unless @{$traits}; |
275 | |
276 | my $meta = $class->meta(); |
277 | |
278 | my $type = ( split /::/, ref $meta )[-1] |
c245d69b |
279 | or Moose->throw_error( |
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280 | 'Cannot determine metaclass type for trait application . Meta isa ' |
4c0b3599 |
281 | . ref $meta ); |
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282 | |
283 | my @resolved_traits |
284 | = map { Moose::Util::resolve_metatrait_alias( $type => $_ ) } |
285 | @$traits; |
286 | |
287 | return unless @resolved_traits; |
288 | |
289 | Moose::Util::MetaRole::apply_metaclass_roles( |
290 | for_class => $class, |
291 | metaclass_roles => \@resolved_traits, |
292 | ); |
293 | } |
294 | |
295 | sub _get_caller { |
296 | # 1 extra level because it's called by import so there's a layer |
297 | # of indirection |
298 | my $offset = 1; |
299 | |
300 | return |
301 | ( ref $_[1] && defined $_[1]->{into} ) ? $_[1]->{into} |
302 | : ( ref $_[1] && defined $_[1]->{into_level} ) |
303 | ? caller( $offset + $_[1]->{into_level} ) |
304 | : caller($offset); |
305 | } |
306 | |
307 | sub _make_unimport_sub { |
308 | shift; |
309 | my $exporting_package = shift; |
310 | my $exports = shift; |
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311 | my $is_removable = shift; |
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312 | my $export_recorder = shift; |
313 | |
314 | return sub { |
315 | my $caller = scalar caller(); |
316 | Moose::Exporter->_remove_keywords( |
317 | $caller, |
318 | [ keys %{$exports} ], |
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319 | $is_removable, |
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320 | $export_recorder, |
321 | ); |
322 | }; |
323 | } |
324 | |
325 | sub _remove_keywords { |
326 | shift; |
327 | my $package = shift; |
328 | my $keywords = shift; |
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329 | my $is_removable = shift; |
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330 | my $recorded_exports = shift; |
331 | |
332 | no strict 'refs'; |
333 | |
334 | foreach my $name ( @{ $keywords } ) { |
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335 | next unless $is_removable->{$name}; |
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336 | |
337 | if ( defined &{ $package . '::' . $name } ) { |
338 | my $sub = \&{ $package . '::' . $name }; |
339 | |
340 | # make sure it is from us |
341 | next unless $recorded_exports->{$sub}; |
342 | |
343 | # and if it is from us, then undef the slot |
344 | delete ${ $package . '::' }{$name}; |
345 | } |
346 | } |
347 | } |
348 | |
349 | 1; |
350 | |
351 | __END__ |
352 | |
353 | =head1 NAME |
354 | |
355 | Moose::Exporter - make an import() and unimport() just like Moose.pm |
356 | |
357 | =head1 SYNOPSIS |
358 | |
359 | package MyApp::Moose; |
360 | |
361 | use strict; |
362 | use warnings; |
363 | |
364 | use Moose (); |
365 | use Moose::Exporter; |
366 | |
367 | Moose::Exporter->setup_import_methods( |
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368 | with_caller => [ 'has_rw', 'sugar2' ], |
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369 | as_is => [ 'sugar3', \&Some::Random::thing ], |
370 | also => 'Moose', |
371 | ); |
372 | |
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373 | sub has_rw { |
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374 | my ($caller, $name, %options) = @_; |
82ad7804 |
375 | Class::MOP::Class->initialize($caller)->add_attribute($name, |
376 | is => 'rw', |
377 | %options, |
378 | ); |
379 | } |
380 | |
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381 | # then later ... |
382 | package MyApp::User; |
383 | |
384 | use MyApp::Moose; |
385 | |
386 | has 'name'; |
6daad0b9 |
387 | has_rw 'size'; |
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388 | thing; |
389 | |
390 | no MyApp::Moose; |
391 | |
392 | =head1 DESCRIPTION |
393 | |
394 | This module encapsulates the logic to export sugar functions like |
395 | C<Moose.pm>. It does this by building custom C<import> and C<unimport> |
396 | methods for your module, based on a spec your provide. |
397 | |
398 | It also lets your "stack" Moose-alike modules so you can export |
399 | Moose's sugar as well as your own, along with sugar from any random |
400 | C<MooseX> module, as long as they all use C<Moose::Exporter>. |
401 | |
402 | =head1 METHODS |
403 | |
404 | This module provides two public methods: |
405 | |
406 | =head2 Moose::Exporter->setup_import_methods(...) |
407 | |
408 | When you call this method, C<Moose::Exporter> build custom C<import> |
409 | and C<unimport> methods for your module. The import method will export |
410 | the functions you specify, and you can also tell it to export |
411 | functions exported by some other module (like C<Moose.pm>). |
412 | |
413 | The C<unimport> method cleans the callers namespace of all the |
414 | exported functions. |
415 | |
416 | This method accepts the following parameters: |
417 | |
418 | =over 4 |
419 | |
420 | =item * with_caller => [ ... ] |
421 | |
422 | This a list of function I<names only> to be exported wrapped and then |
423 | exported. The wrapper will pass the name of the calling package as the |
424 | first argument to the function. Many sugar functions need to know |
425 | their caller so they can get the calling package's metaclass object. |
426 | |
427 | =item * as_is => [ ... ] |
428 | |
429 | This a list of function names or sub references to be exported |
430 | as-is. You can identify a subroutine by reference, which is handy to |
431 | re-export some other module's functions directly by reference |
432 | (C<\&Some::Package::function>). |
433 | |
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434 | If you do export some other packages function, this function will |
435 | never be removed by the C<unimport> method. The reason for this is we |
436 | cannot know if the caller I<also> explicitly imported the sub |
437 | themselves, and therefore wants to keep it. |
438 | |
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439 | =item * also => $name or \@names |
440 | |
441 | This is a list of modules which contain functions that the caller |
442 | wants to export. These modules must also use C<Moose::Exporter>. The |
443 | most common use case will be to export the functions from C<Moose.pm>. |
444 | |
445 | C<Moose::Exporter> also makes sure all these functions get removed |
446 | when C<unimport> is called. |
447 | |
448 | =back |
449 | |
450 | =head2 Moose::Exporter->build_import_methods(...) |
451 | |
452 | Returns two code refs, one for import and one for unimport. |
453 | |
454 | Used by C<setup_import_methods>. |
455 | |
456 | =head1 IMPORTING AND init_meta |
457 | |
458 | If you want to set an alternative base object class or metaclass |
459 | class, simply define an C<init_meta> method in your class. The |
460 | C<import> method that C<Moose::Exporter> generates for you will call |
461 | this method (if it exists). It will always pass the caller to this |
462 | method via the C<for_class> parameter. |
463 | |
464 | Most of the time, your C<init_meta> method will probably just call C<< |
465 | Moose->init_meta >> to do the real work: |
466 | |
467 | sub init_meta { |
468 | shift; # our class name |
469 | return Moose->init_meta( @_, metaclass => 'My::Metaclass' ); |
470 | } |
471 | |
472 | =head1 METACLASS TRAITS |
473 | |
474 | The C<import> method generated by C<Moose::Exporter> will allow the |
475 | user of your module to specify metaclass traits in a C<-traits> |
476 | parameter passed as part of the import: |
477 | |
478 | use Moose -traits => 'My::Meta::Trait'; |
479 | |
480 | use Moose -traits => [ 'My::Meta::Trait', 'My::Other::Trait' ]; |
481 | |
482 | These traits will be applied to the caller's metaclass |
483 | instance. Providing traits for an exporting class that does not create |
484 | a metaclass for the caller is an error. |
485 | |
486 | =head1 AUTHOR |
487 | |
488 | Dave Rolsky E<lt>autarch@urth.orgE<gt> |
489 | |
490 | This is largely a reworking of code in Moose.pm originally written by |
491 | Stevan Little and others. |
492 | |
493 | =head1 COPYRIGHT AND LICENSE |
494 | |
495 | Copyright 2008 by Infinity Interactive, Inc. |
496 | |
497 | L<http://www.iinteractive.com> |
498 | |
499 | This library is free software; you can redistribute it and/or modify |
500 | it under the same terms as Perl itself. |
501 | |
502 | =cut |