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c28ee69c |
1 | #!/usr/bin/perl |
2 | |
3 | package Catalyst::Plugin::Cache; |
2e4bde89 |
4 | use base qw/Class::Data::Inheritable Class::Accessor::Fast/; |
c28ee69c |
5 | |
6 | use strict; |
7 | use warnings; |
8 | |
d6861a7f |
9 | our $VERSION = "0.01"; |
10 | |
c28ee69c |
11 | use Scalar::Util (); |
23b2d59b |
12 | use Catalyst::Utils (); |
c28ee69c |
13 | use Carp (); |
14 | use NEXT; |
15 | |
2e4bde89 |
16 | use Catalyst::Plugin::Cache::Curried; |
17 | |
c28ee69c |
18 | __PACKAGE__->mk_classdata( "_cache_backends" ); |
2e4bde89 |
19 | __PACKAGE__->mk_accessors( "_default_curried_cache" ); |
c28ee69c |
20 | |
21 | sub setup { |
22 | my $app = shift; |
23 | |
24 | # set it once per app, not once per plugin, |
25 | # and don't overwrite if some plugin was wicked |
26 | $app->_cache_backends({}) unless $app->_cache_backends; |
27 | |
28 | my $ret = $app->NEXT::setup( @_ ); |
29 | |
30 | $app->setup_cache_backends; |
31 | |
32 | $ret; |
33 | } |
34 | |
23b2d59b |
35 | sub get_default_cache_backend_config { |
36 | my ( $app, $name ) = @_; |
37 | $app->config->{cache}{backend} || $app->get_cache_backend_config("default"); |
38 | } |
39 | |
40 | sub get_cache_backend_config { |
41 | my ( $app, $name ) = @_; |
42 | $app->config->{cache}{backends}{$name}; |
43 | } |
44 | |
45 | sub setup_cache_backends { |
46 | my $app = shift; |
47 | |
48 | # give plugins a chance to find things for themselves |
49 | $app->NEXT::setup_cache_backends; |
50 | |
51 | foreach my $name ( keys %{ $app->config->{cache}{backends} } ) { |
52 | next if $app->get_cache_backend( $name ); |
53 | $app->setup_generic_cache_backend( $name, $app->get_cache_backend_config( $name ) || {} ); |
54 | } |
55 | |
33002c69 |
56 | if ( !$app->get_cache_backend("default") ) { |
57 | local $@; |
58 | eval { $app->setup_generic_cache_backend( default => $app->get_default_cache_backend_config || {} ) }; |
85a748b9 |
59 | } |
23b2d59b |
60 | } |
61 | |
62 | sub default_cache_store { |
63 | my $app = shift; |
64 | $app->config->{cache}{default_store} || $app->guess_default_cache_store; |
65 | } |
66 | |
67 | sub guess_default_cache_store { |
68 | my $app = shift; |
69 | |
70 | my @stores = map { /Cache::Store::(.*)$/ ? $1 : () } $app->registered_plugins; |
71 | |
72 | if ( @stores == 1 ) { |
73 | return $stores[0]; |
74 | } else { |
75 | Carp::croak "You must configure a default store type unless you use exactly one store plugin."; |
76 | } |
77 | } |
78 | |
79 | sub setup_generic_cache_backend { |
80 | my ( $app, $name, $config ) = @_; |
81 | my %config = %$config; |
82 | |
83 | if ( my $class = delete $config{class} ) { |
887cc08f |
84 | $app->setup_cache_backend_by_class( $name, $class, \%config ); |
23b2d59b |
85 | } elsif ( my $store = delete $config->{store} || $app->default_cache_store ) { |
86 | my $method = lc("setup_${store}_cache_backend"); |
87 | |
88 | Carp::croak "You must load the $store cache store plugin (if it exists). ". |
89 | "Please consult the Catalyst::Plugin::Cache documentation on how to configure hetrogeneous stores." |
90 | unless $app->can($method); |
91 | |
887cc08f |
92 | $app->$method( $name, \%config ); |
23b2d59b |
93 | } else { |
94 | $app->log->warn("Couldn't setup the cache backend named '$name'"); |
95 | } |
96 | } |
97 | |
98 | sub setup_cache_backend_by_class { |
99 | my ( $app, $name, $class, @args ) = @_; |
100 | Catalyst::Utils::ensure_class_loaded( $class ); |
101 | $app->register_cache_backend( $name => $class->new( @args ) ); |
102 | } |
103 | |
104 | # end of spaghetti setup DWIM |
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105 | |
106 | sub cache { |
2e4bde89 |
107 | my ( $c, @meta ) = @_; |
108 | |
109 | if ( @meta == 1 ) { |
110 | my $name = $meta[0]; |
111 | return ( $c->get_preset_curried($name) || $c->get_cache_backend($name) ); |
112 | } elsif ( !@meta ) { |
113 | # be nice and always return the same one for the simplest case |
114 | return ( $c->_default_curried_cache || $c->_default_curried_cache( $c->curry_cache( @meta ) ) ); |
c28ee69c |
115 | } else { |
2e4bde89 |
116 | return $c->curry_cache( @meta ); |
c28ee69c |
117 | } |
118 | } |
119 | |
5a00a29b |
120 | sub construct_curried_cache { |
121 | my ( $c, @meta ) = @_; |
122 | return $c->curried_cache_class( @meta )->new( @meta ); |
123 | } |
124 | |
125 | sub curried_cache_class { |
126 | my ( $c, @meta ) = @_; |
127 | $c->config->{cache}{curried_class} || "Catalyst::Plugin::Cache::Curried"; |
128 | } |
129 | |
2e4bde89 |
130 | sub curry_cache { |
131 | my ( $c, @meta ) = @_; |
5a00a29b |
132 | return $c->construct_curried_cache( $c, $c->_cache_caller_meta, @meta ); |
2e4bde89 |
133 | } |
134 | |
135 | sub get_preset_curried { |
136 | my ( $c, $name ) = @_; |
137 | |
138 | if ( ref( my $preset = $c->config->{cache}{profiles}{$name} ) ) { |
139 | return $preset if Scalar::Util::blessed($preset); |
140 | |
141 | my @meta = ( ( ref $preset eq "HASH" ) ? %$preset : @$preset ); |
142 | return $c->curry_cache( @meta ); |
143 | } |
144 | |
145 | return; |
146 | } |
147 | |
c28ee69c |
148 | sub get_cache_backend { |
149 | my ( $c, $name ) = @_; |
150 | $c->_cache_backends->{$name}; |
151 | } |
152 | |
153 | sub register_cache_backend { |
154 | my ( $c, $name, $backend ) = @_; |
155 | |
156 | no warnings 'uninitialized'; |
157 | Carp::croak("$backend does not look like a cache backend - " |
aed484da |
158 | . "it must be an object supporting get, set and remove") |
159 | unless eval { $backend->can("get") && $backend->can("set") && $backend->can("remove") }; |
c28ee69c |
160 | |
161 | $c->_cache_backends->{$name} = $backend; |
162 | } |
163 | |
164 | sub unregister_cache_backend { |
165 | my ( $c, $name ) = @_; |
166 | delete $c->_cache_backends->{$name}; |
167 | } |
168 | |
169 | sub default_cache_backend { |
170 | my $c = shift; |
171 | $c->get_cache_backend( "default" ) || $c->temporary_cache_backend; |
172 | } |
173 | |
174 | sub temporary_cache_backend { |
175 | my $c = shift; |
176 | die "FIXME - make up an in memory cache backend, that hopefully works well for the current engine"; |
177 | } |
178 | |
5a00a29b |
179 | sub _cache_caller_meta { |
180 | my $c = shift; |
181 | |
182 | my ( $caller, $component, $controller ); |
183 | |
184 | for my $i ( 0 .. 15 ) { # don't look to far |
185 | my @info = caller(2 + $i) or last; |
186 | |
85a748b9 |
187 | $caller ||= \@info unless $info[0] =~ /Plugin::Cache/; |
5a00a29b |
188 | $component ||= \@info if $info[0]->isa("Catalyst::Component"); |
189 | $controller ||= \@info if $info[0]->isa("Catalyst::Controller"); |
190 | |
191 | last if $caller && $component && $controller; |
192 | } |
193 | |
85a748b9 |
194 | my ( $caller_pkg, $component_pkg, $controller_pkg ) = |
195 | map { $_ ? $_->[0] : undef } $caller, $component, $controller; |
196 | |
5a00a29b |
197 | return ( |
85a748b9 |
198 | 'caller' => $caller_pkg, |
199 | component => $component_pkg, |
200 | controller => $controller_pkg, |
201 | caller_frame => $caller, |
202 | component_frame => $component, |
203 | controller_frame => $controller, |
5a00a29b |
204 | ); |
205 | } |
206 | |
c28ee69c |
207 | # this gets a shit name so that the plugins can override a good name |
208 | sub choose_cache_backend_wrapper { |
209 | my ( $c, @meta ) = @_; |
210 | |
c627df81 |
211 | Carp::croak("metadata must be an even sized list") unless @meta % 2 == 0; |
c28ee69c |
212 | |
213 | my %meta = @meta; |
5a00a29b |
214 | |
215 | unless ( exists $meta{'caller'} ) { |
216 | my %caller = $c->_cache_caller_meta; |
217 | @meta{keys %caller} = values %caller; |
218 | } |
c28ee69c |
219 | |
220 | # allow the cache client to specify who it wants to cache with (but loeave room for a hook) |
221 | if ( exists $meta{backend} ) { |
222 | if ( Scalar::Util::blessed($meta{backend}) ) { |
223 | return $meta{backend}; |
224 | } else { |
225 | return $c->get_cache_backend( $meta{backend} ) || $c->default_cache_backend; |
226 | } |
227 | }; |
228 | |
c28ee69c |
229 | if ( my $chosen = $c->choose_cache_backend( %meta ) ) { |
230 | $chosen = $c->get_cache_backend( $chosen ) unless Scalar::Util::blessed($chosen); # if it's a name find it |
231 | return $chosen if Scalar::Util::blessed($chosen); # only return if it was an object or name lookup worked |
232 | |
233 | # FIXME |
234 | # die "no such backend"? |
235 | # currently, we fall back to default |
236 | } |
237 | |
238 | return $c->default_cache_backend; |
239 | } |
240 | |
241 | sub choose_cache_backend { shift->NEXT::choose_cache_backend( @_ ) } # a convenient fallback |
242 | |
243 | sub cache_set { |
244 | my ( $c, $key, $value, @meta ) = @_; |
245 | $c->choose_cache_backend_wrapper( key => $key, value => $value, @meta )->set( $key, $value ); |
246 | } |
247 | |
248 | sub cache_get { |
249 | my ( $c, $key, @meta ) = @_; |
250 | $c->choose_cache_backend_wrapper( key => $key, @meta )->get( $key ); |
251 | } |
252 | |
aed484da |
253 | sub cache_remove { |
c28ee69c |
254 | my ( $c, $key, @meta ) = @_; |
aed484da |
255 | $c->choose_cache_backend_wrapper( key => $key, @meta )->remove( $key ); |
c28ee69c |
256 | } |
257 | |
258 | __PACKAGE__; |
259 | |
260 | __END__ |
261 | |
262 | =pod |
263 | |
264 | =head1 NAME |
265 | |
85a748b9 |
266 | Catalyst::Plugin::Cache - Flexible caching support for Catalyst. |
c28ee69c |
267 | |
268 | =head1 SYNOPSIS |
269 | |
5a00a29b |
270 | use Catalyst qw/ |
271 | Cache |
272 | /; |
273 | |
274 | # configure a backend or use a store plugin |
85a748b9 |
275 | __PACKAGE__->config->{cache}{backend} = { |
276 | class => "Cache::Bounded", |
277 | # ... params ... |
278 | }; |
5a00a29b |
279 | |
c627df81 |
280 | # In a controller: |
5a00a29b |
281 | |
282 | sub foo : Local { |
283 | my ( $self, $c, $id ) = @_; |
284 | |
285 | my $cache = $c->cache; |
286 | |
287 | my $result; |
288 | |
289 | unless ( $result = $cache->get( $id ) ) { |
c627df81 |
290 | # ... calculate result ... |
5a00a29b |
291 | $c->cache->set( $id, $result ); |
292 | } |
293 | }; |
c28ee69c |
294 | |
295 | =head1 DESCRIPTION |
296 | |
c627df81 |
297 | This plugin gives you access to a variety of systems for caching |
298 | data. It allows you to use a very simple configuration API, while |
299 | maintaining the possibility of flexibility when you need it later. |
5a00a29b |
300 | |
c627df81 |
301 | Among its features are support for multiple backends, segmentation based |
302 | on component or controller, keyspace partitioning, and so more, in |
303 | various subsidiary plugins. |
5a00a29b |
304 | |
85a748b9 |
305 | =head1 METHODS |
306 | |
307 | =over 4 |
308 | |
309 | =item cache $profile_name |
310 | |
311 | =item cache %meta |
312 | |
c627df81 |
313 | Return a curried object with metadata from C<$profile_name> or as |
314 | explicitly specified. |
85a748b9 |
315 | |
c627df81 |
316 | If a profile by the name C<$profile_name> doesn't exist, but a backend |
317 | object by that name does exist, the backend will be returned instead, |
318 | since the interface for curried caches and backends is almost identical. |
85a748b9 |
319 | |
c627df81 |
320 | This method can also be called without arguments, in which case is |
321 | treated as though the C<%meta> hash was empty. |
85a748b9 |
322 | |
c627df81 |
323 | See L</METADATA> for details. |
85a748b9 |
324 | |
325 | =item curry_cache %meta |
326 | |
c627df81 |
327 | Return a L<Catalyst::Plugin::Cache::Curried> object, curried with C<%meta>. |
85a748b9 |
328 | |
c627df81 |
329 | See L</METADATA> for details. |
85a748b9 |
330 | |
331 | =item cache_set $key, $value, %meta |
332 | |
333 | =item cache_get $key, %meta |
334 | |
335 | =item cache_remove $key, %meta |
336 | |
c627df81 |
337 | These cache operations will call L<choose_cache_backend> with %meta, and |
338 | then call C<set>, C<get>, or C<remove> on the resulting backend object. |
85a748b9 |
339 | |
340 | =item choose_cache_backend %meta |
341 | |
c627df81 |
342 | Select a backend object. This should return undef if no specific backend |
343 | was selected - its caller will handle getting C<default_cache_backend> |
344 | on its own. |
85a748b9 |
345 | |
346 | This method is typically used by plugins. |
347 | |
348 | =item get_cache_backend $name |
349 | |
350 | Get a backend object by name. |
351 | |
352 | =item default_cache_backend |
353 | |
354 | Return the default backend object. |
355 | |
356 | =item temporary_cache_backend |
357 | |
c627df81 |
358 | When no default cache backend is configured this method might return a |
359 | backend known to work well with the current L<Catalyst::Engine>. This is |
360 | a stub. |
85a748b9 |
361 | |
362 | =item |
363 | |
364 | =back |
365 | |
c627df81 |
366 | =head1 METADATA |
85a748b9 |
367 | |
368 | =head2 Introduction |
369 | |
c627df81 |
370 | Whenever you set or retrieve a key you may specify additional metadata |
371 | that will be used to select a specific backend. |
85a748b9 |
372 | |
373 | This metadata is very freeform, and the only key that has any meaning by |
374 | default is the C<backend> key which can be used to explicitly choose a backend |
375 | by name. |
376 | |
c627df81 |
377 | The C<choose_cache_backend> method can be overridden in order to |
378 | facilitate more intelligent backend selection. For example, |
379 | L<Catalyst::Plugin::Cache::Choose::KeyRegexes> overrides that method to |
380 | select a backend based on key regexes. |
85a748b9 |
381 | |
c627df81 |
382 | Another example is a L<Catalyst::Plugin::Cache::ControllerNamespacing>, |
383 | which wraps backends in objects that perform key mangling, in order to |
384 | keep caches namespaced per controller. |
85a748b9 |
385 | |
386 | However, this is generally left as a hook for larger, more complex |
c627df81 |
387 | applications. Most configurations should make due XXXX |
85a748b9 |
388 | |
c627df81 |
389 | The simplest way to dynamically select a backend is based on the |
390 | L</Cache Profiles> configuration. |
85a748b9 |
391 | |
392 | =head2 Meta Data Keys |
393 | |
394 | C<choose_cache_backend> is called with some default keys. |
395 | |
396 | =over 4 |
397 | |
398 | =item key |
399 | |
c627df81 |
400 | Supplied by C<cache_get>, C<cache_set>, and C<cache_remove>. |
85a748b9 |
401 | |
402 | =item value |
403 | |
c627df81 |
404 | Supplied by C<cache_set>. |
85a748b9 |
405 | |
406 | =item caller |
407 | |
408 | The package name of the innermost caller that doesn't match |
409 | C<qr/Plugin::Cache/>. |
410 | |
411 | =item caller_frame |
412 | |
413 | The entire C<caller($i)> frame of C<caller>. |
414 | |
415 | =item component |
416 | |
c627df81 |
417 | The package name of the innermost caller who C<isa> |
418 | L<Catalyst::Component>. |
85a748b9 |
419 | |
420 | =item component_frame |
421 | |
422 | This entire C<caller($i)> frame of C<component>. |
423 | |
424 | =item controller |
425 | |
c627df81 |
426 | The package name of the innermost caller who C<isa> |
427 | L<Catalyst::Controller>. |
85a748b9 |
428 | |
429 | =item controller_frame |
430 | |
431 | This entire C<caller($i)> frame of C<controller>. |
432 | |
433 | =back |
434 | |
c627df81 |
435 | =head2 Metadata Currying |
85a748b9 |
436 | |
c627df81 |
437 | In order to avoid specifying C<%meta> over and over again you may call |
438 | C<cache> or C<curry_cache> with C<%meta> once, and get back a B<curried |
439 | cache object>. This object responds to the methods C<get>, C<set>, and |
440 | C<remove>, by appending its captured metadata and delegating them to |
441 | C<cache_get>, C<cache_set>, and C<cache_remove>. |
85a748b9 |
442 | |
443 | This is simpler than it sounds. |
444 | |
445 | Here is an example using currying: |
446 | |
447 | my $cache = $c->cache( %meta ); # cache is curried |
448 | |
449 | $cache->set( $key, $value ); |
450 | |
451 | $cache->get( $key ); |
452 | |
453 | And here is an example without using currying: |
454 | |
455 | $c->cache_set( $key, $value, %meta ); |
456 | |
457 | $c->cache_get( $key, %meta ); |
458 | |
459 | See L<Catalyst::Plugin::Cache::Curried> for details. |
460 | |
0f0237aa |
461 | =head1 CONFIGURATION |
462 | |
85a748b9 |
463 | $c->config->{cache} = { |
464 | ... |
465 | }; |
0f0237aa |
466 | |
c627df81 |
467 | All configuration parameters should be provided in a hash reference |
468 | under the C<cache> key in the C<config> hash. |
0f0237aa |
469 | |
85a748b9 |
470 | =head2 Backend Configuration |
471 | |
472 | Configuring backend objects is done by adding hash entries under the |
c627df81 |
473 | C<backends> key in the main config. |
85a748b9 |
474 | |
c627df81 |
475 | A special case is that the hash key under the C<backend> (singular) key |
476 | of the main config is assumed to be the backend named C<default>. |
85a748b9 |
477 | |
0f0237aa |
478 | =over 4 |
479 | |
480 | =item class |
481 | |
85a748b9 |
482 | Instantiate a backend from a L<Cache> compatible class. E.g. |
0f0237aa |
483 | |
85a748b9 |
484 | $c->config->{cache}{backends}{small_things} = { |
485 | class => "Cache::Bounded", |
486 | interval => 1000, |
487 | size => 10000, |
488 | }; |
489 | |
490 | $c->config->{cache}{backends}{large_things} = { |
c627df81 |
491 | class => "Cache::Memcached::Managed", |
85a748b9 |
492 | data => '1.2.3.4:1234', |
493 | }; |
0f0237aa |
494 | |
85a748b9 |
495 | The options in the hash are passed to the class's C<new> method. |
0f0237aa |
496 | |
85a748b9 |
497 | The class will be C<required> as necessary during setup time. |
0f0237aa |
498 | |
85a748b9 |
499 | =item store |
0f0237aa |
500 | |
c627df81 |
501 | Instantiate a backend using a store plugin, e.g. |
0f0237aa |
502 | |
85a748b9 |
503 | $c->config->{cache}{backend} = { |
504 | store => "FastMmap", |
505 | }; |
0f0237aa |
506 | |
c627df81 |
507 | Store plugins typically require less configuration because they are |
508 | specialized for L<Catalyst> applications. For example |
85a748b9 |
509 | L<Catalyst::Plugin::Cache::Store::FastMmap> will specify a default |
c627df81 |
510 | C<share_file>, and additionally use a subclass of L<Cache::FastMmap> |
511 | that can also store non reference data. |
85a748b9 |
512 | |
513 | The store plugin must be loaded. |
514 | |
515 | =back |
0f0237aa |
516 | |
85a748b9 |
517 | =head2 Cache Profiles |
518 | |
519 | =over 4 |
0f0237aa |
520 | |
521 | =item profiles |
522 | |
c627df81 |
523 | Supply your own predefined profiles for cache metadata, when using the |
524 | C<cache> method. |
85a748b9 |
525 | |
526 | For example when you specify |
527 | |
528 | $c->config->{cache}{profiles}{thumbnails} = { |
529 | backend => "large_things", |
530 | }; |
531 | |
532 | And then get a cache object like this: |
533 | |
534 | $c->cache("thumbnails"); |
535 | |
536 | It is the same as if you had done: |
537 | |
538 | $c->cache( backend => "large_things" ); |
539 | |
540 | =back |
541 | |
c627df81 |
542 | =head2 Miscellaneous Configuration |
85a748b9 |
543 | |
544 | =over 4 |
545 | |
546 | =item default_store |
547 | |
c627df81 |
548 | When you do not specify a C<store> parameter in the backend |
549 | configuration this one will be used instead. This configuration |
550 | parameter is not necessary if only one store plugin is loaded. |
0f0237aa |
551 | |
552 | =back |
553 | |
554 | =head1 TERMINOLOGY |
23b2d59b |
555 | |
556 | =over 4 |
557 | |
558 | =item backend |
559 | |
560 | An object that responds to the methods detailed in |
561 | L<Catalyst::Plugin::Cache::Backend> (or more). |
562 | |
563 | =item store |
564 | |
c627df81 |
565 | A plugin that provides backends of a certain type. This is a bit like a |
566 | factory. |
23b2d59b |
567 | |
0f0237aa |
568 | =item cache |
569 | |
570 | Stored key/value pairs of data for easy re-access. |
571 | |
c627df81 |
572 | =item metadata |
85a748b9 |
573 | |
c627df81 |
574 | "Extra" information about the item being stored, which can be used to |
575 | locate an appropriate backend. |
85a748b9 |
576 | |
23b2d59b |
577 | =item curried cache |
578 | |
0f0237aa |
579 | my $cache = $c->cache(type => 'thumbnails'); |
580 | $cache->set('pic01', $thumbnaildata); |
581 | |
c627df81 |
582 | A cache which has been pre-configured with a particular set of |
583 | namespacing data. In the example the cache returned could be one |
584 | specifically tuned for storing thumbnails. |
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585 | |
c627df81 |
586 | An object that responds to C<get>, C<set>, and C<remove>, and will |
587 | automatically add metadata to calls to C<< $c->cache_get >>, etc. |
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588 | |
589 | =back |
590 | |
772299b1 |
591 | =head1 SEE ALSO |
592 | |
c627df81 |
593 | L<Cache> - the generic cache API on CPAN. |
772299b1 |
594 | |
595 | L<Catalyst::Plugin::Cache::Store> - how to write a store plugin. |
596 | |
597 | L<Catalyst::Plugin::Cache::Curried> - the interface for curried caches. |
598 | |
599 | L<Catalyst::Plugin::Cache::Choose::KeyRegexes> - choose a backend based on |
600 | regex matching on the keys. Can be used to partition the keyspace. |
601 | |
602 | L<Catalyst::Plugin::Cache::ControllerNamespacing> - wrap backend objects in a |
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603 | name mangler so that every controller gets its own keyspace. |
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604 | |
271f5106 |
605 | =head1 AUTHOR |
606 | |
607 | Yuval Kogman, C<nothingmuch@woobling.org> |
608 | |
609 | =head1 COPYRIGHT & LICENSE |
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610 | |
271f5106 |
611 | Copyright (c) Yuval Kogman, 2006. All rights reserved. |
612 | |
613 | This library is free software, you can redistribute it and/or modify it under |
614 | the same terms as Perl itself, as well as under the terms of the MIT license. |
615 | |
616 | =cut |
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617 | |