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40aef9d6 |
1 | package namespace::clean; |
04312494 |
2 | # ABSTRACT: Keep imports and functions out of your namespace |
40aef9d6 |
3 | |
4 | use warnings; |
5 | use strict; |
6 | |
8177960a |
7 | use vars qw( $STORAGE_VAR ); |
9887772b |
8 | use Package::Stash; |
40aef9d6 |
9 | |
1202ce4b |
10 | our $VERSION = '0.20_01'; |
fa84e425 |
11 | |
8177960a |
12 | $STORAGE_VAR = '__NAMESPACE_CLEAN_STORAGE'; |
40aef9d6 |
13 | |
9887772b |
14 | BEGIN { |
1cd61d2e |
15 | |
7b026c56 |
16 | use warnings; |
17 | use strict; |
18 | |
1cd61d2e |
19 | # when changing also change in Makefile.PL |
20 | my $b_h_eos_req = '0.07'; |
21 | |
9887772b |
22 | if (eval { |
23 | require B::Hooks::EndOfScope; |
1cd61d2e |
24 | B::Hooks::EndOfScope->VERSION($b_h_eos_req); |
9887772b |
25 | 1 |
26 | } ) { |
27 | B::Hooks::EndOfScope->import('on_scope_end'); |
28 | } |
29 | else { |
30 | eval <<'PP' or die $@; |
31 | |
1cd61d2e |
32 | use Tie::Hash (); |
33 | |
34 | { |
35 | package namespace::clean::_TieHintHash; |
36 | |
7b026c56 |
37 | use warnings; |
38 | use strict; |
39 | |
1cd61d2e |
40 | use base 'Tie::ExtraHash'; |
41 | } |
42 | |
9887772b |
43 | { |
44 | package namespace::clean::_ScopeGuard; |
45 | |
7b026c56 |
46 | use warnings; |
47 | use strict; |
48 | |
9887772b |
49 | sub arm { bless [ $_[1] ] } |
50 | |
51 | sub DESTROY { $_[0]->[0]->() } |
52 | } |
53 | |
9887772b |
54 | |
55 | sub on_scope_end (&) { |
56 | $^H |= 0x020000; |
57 | |
58 | if( my $stack = tied( %^H ) ) { |
1cd61d2e |
59 | if ( (my $c = ref $stack) ne 'namespace::clean::_TieHintHash') { |
60 | die <<EOE; |
61 | ======================================================================== |
62 | !!! F A T A L E R R O R !!! |
63 | |
64 | foreign tie() of %^H detected |
65 | ======================================================================== |
66 | |
67 | namespace::clean is currently operating in pure-perl fallback mode, because |
68 | your system is lacking the necessary dependency B::Hooks::EndOfScope $b_h_eos_req. |
69 | In this mode namespace::clean expects to be able to tie() the hinthash %^H, |
70 | however it is apparently already tied by means unknown to the tie-class |
71 | $c |
72 | |
73 | Since this is a no-win situation execution will abort here and now. Please |
74 | try to find out which other module is relying on hinthash tie() ability, |
75 | and file a bug for both the perpetrator and namespace::clean, so that the |
76 | authors can figure out an acceptable way of moving forward. |
77 | |
78 | EOE |
79 | } |
9887772b |
80 | push @$stack, namespace::clean::_ScopeGuard->arm(shift); |
81 | } |
82 | else { |
1cd61d2e |
83 | tie( %^H, 'namespace::clean::_TieHintHash', namespace::clean::_ScopeGuard->arm(shift) ); |
9887772b |
84 | } |
85 | } |
86 | |
87 | 1; |
88 | |
89 | PP |
90 | |
91 | } |
92 | } |
93 | |
40aef9d6 |
94 | =head1 SYNOPSIS |
95 | |
96 | package Foo; |
97 | use warnings; |
98 | use strict; |
99 | |
6c0ece9b |
100 | use Carp qw(croak); # 'croak' will be removed |
40aef9d6 |
101 | |
6c0ece9b |
102 | sub bar { 23 } # 'bar' will be removed |
40aef9d6 |
103 | |
6c0ece9b |
104 | # remove all previously defined functions |
40aef9d6 |
105 | use namespace::clean; |
106 | |
6c0ece9b |
107 | sub baz { bar() } # 'baz' still defined, 'bar' still bound |
40aef9d6 |
108 | |
6c0ece9b |
109 | # begin to collection function names from here again |
9b680ffe |
110 | no namespace::clean; |
111 | |
6c0ece9b |
112 | sub quux { baz() } # 'quux' will be removed |
9b680ffe |
113 | |
6c0ece9b |
114 | # remove all functions defined after the 'no' unimport |
9b680ffe |
115 | use namespace::clean; |
116 | |
6c0ece9b |
117 | # Will print: 'No', 'No', 'Yes' and 'No' |
40aef9d6 |
118 | print +(__PACKAGE__->can('croak') ? 'Yes' : 'No'), "\n"; |
119 | print +(__PACKAGE__->can('bar') ? 'Yes' : 'No'), "\n"; |
120 | print +(__PACKAGE__->can('baz') ? 'Yes' : 'No'), "\n"; |
9b680ffe |
121 | print +(__PACKAGE__->can('quux') ? 'Yes' : 'No'), "\n"; |
40aef9d6 |
122 | |
123 | 1; |
124 | |
125 | =head1 DESCRIPTION |
126 | |
de673bbf |
127 | =head2 Keeping packages clean |
128 | |
40aef9d6 |
129 | When you define a function, or import one, into a Perl package, it will |
130 | naturally also be available as a method. This does not per se cause |
131 | problems, but it can complicate subclassing and, for example, plugin |
04312494 |
132 | classes that are included via multiple inheritance by loading them as |
6c0ece9b |
133 | base classes. |
40aef9d6 |
134 | |
135 | The C<namespace::clean> pragma will remove all previously declared or |
136 | imported symbols at the end of the current package's compile cycle. |
6c0ece9b |
137 | Functions called in the package itself will still be bound by their |
138 | name, but they won't show up as methods on your class or instances. |
139 | |
140 | By unimporting via C<no> you can tell C<namespace::clean> to start |
141 | collecting functions for the next C<use namespace::clean;> specification. |
40aef9d6 |
142 | |
53e92ec5 |
143 | You can use the C<-except> flag to tell C<namespace::clean> that you |
472d4b1e |
144 | don't want it to remove a certain function or method. A common use would |
145 | be a module exporting an C<import> method along with some functions: |
53e92ec5 |
146 | |
147 | use ModuleExportingImport; |
148 | use namespace::clean -except => [qw( import )]; |
149 | |
472d4b1e |
150 | If you just want to C<-except> a single sub, you can pass it directly. |
151 | For more than one value you have to use an array reference. |
152 | |
271df965 |
153 | =head2 Explicitly removing functions when your scope is compiled |
de673bbf |
154 | |
271df965 |
155 | It is also possible to explicitly tell C<namespace::clean> what packages |
de673bbf |
156 | to remove when the surrounding scope has finished compiling. Here is an |
157 | example: |
158 | |
159 | package Foo; |
160 | use strict; |
161 | |
162 | # blessed NOT available |
163 | |
164 | sub my_class { |
165 | use Scalar::Util qw( blessed ); |
166 | use namespace::clean qw( blessed ); |
167 | |
168 | # blessed available |
169 | return blessed shift; |
170 | } |
171 | |
172 | # blessed NOT available |
173 | |
1a1be5dc |
174 | =head2 Moose |
175 | |
176 | When using C<namespace::clean> together with L<Moose> you want to keep |
177 | the installed C<meta> method. So your classes should look like: |
178 | |
179 | package Foo; |
180 | use Moose; |
181 | use namespace::clean -except => 'meta'; |
182 | ... |
183 | |
184 | Same goes for L<Moose::Role>. |
185 | |
fcfe7810 |
186 | =head2 Cleaning other packages |
187 | |
188 | You can tell C<namespace::clean> that you want to clean up another package |
189 | instead of the one importing. To do this you have to pass in the C<-cleanee> |
190 | option like this: |
191 | |
192 | package My::MooseX::namespace::clean; |
193 | use strict; |
194 | |
195 | use namespace::clean (); # no cleanup, just load |
196 | |
197 | sub import { |
198 | namespace::clean->import( |
199 | -cleanee => scalar(caller), |
200 | -except => 'meta', |
201 | ); |
202 | } |
203 | |
204 | If you don't care about C<namespace::clean>s discover-and-C<-except> logic, and |
205 | just want to remove subroutines, try L</clean_subroutines>. |
206 | |
fa84e425 |
207 | =head1 METHODS |
208 | |
209 | =head2 clean_subroutines |
40aef9d6 |
210 | |
fcfe7810 |
211 | This exposes the actual subroutine-removal logic. |
212 | |
213 | namespace::clean->clean_subroutines($cleanee, qw( subA subB )); |
214 | |
215 | will remove C<subA> and C<subB> from C<$cleanee>. Note that this will remove the |
216 | subroutines B<immediately> and not wait for scope end. If you want to have this |
217 | effect at a specific time (e.g. C<namespace::clean> acts on scope compile end) |
218 | it is your responsibility to make sure it runs at that time. |
40aef9d6 |
219 | |
220 | =cut |
221 | |
017bd598 |
222 | my $sub_utils_loaded; |
223 | my $DebuggerRename = sub { |
224 | my ($f, $sub, $cleanee_stash, $deleted_stash) = @_; |
225 | |
226 | if (! defined $sub_utils_loaded ) { |
227 | $sub_utils_loaded = do { |
228 | my $sn_ver = 0.04; |
229 | eval { require Sub::Name; Sub::Name->VERSION($sn_ver) } |
230 | or die "Sub::Name $sn_ver required when running under -d or equivalent: $@"; |
231 | |
232 | my $si_ver = 0.04; |
233 | eval { require Sub::Identify; Sub::Identify->VERSION($si_ver) } |
234 | or die "Sub::Identify $si_ver required when running under -d or equivalent: $@"; |
fcfe7810 |
235 | |
017bd598 |
236 | 1; |
237 | } ? 1 : 0; |
238 | } |
239 | |
240 | if ( Sub::Identify::sub_fullname($sub) eq ($cleanee_stash->name . "::$f") ) { |
241 | my $new_fq = $deleted_stash->name . "::$f"; |
242 | Sub::Name::subname($new_fq, $sub); |
243 | $deleted_stash->add_symbol("&$f", $sub); |
244 | } |
245 | }; |
246 | |
247 | my $RemoveSubs = sub { |
de673bbf |
248 | my $cleanee = shift; |
249 | my $store = shift; |
16d8eca5 |
250 | my $cleanee_stash = Package::Stash->new($cleanee); |
017bd598 |
251 | my $deleted_stash; |
252 | |
de673bbf |
253 | SYMBOL: |
254 | for my $f (@_) { |
017bd598 |
255 | |
de673bbf |
256 | # ignore already removed symbols |
257 | next SYMBOL if $store->{exclude}{ $f }; |
de673bbf |
258 | |
017bd598 |
259 | my $sub = $cleanee_stash->get_symbol("&$f") |
260 | or next SYMBOL; |
226432f6 |
261 | |
017bd598 |
262 | if ($^P and ref(\$cleanee_stash->namespace->{$f}) eq 'GLOB') { |
226432f6 |
263 | # convince the Perl debugger to work |
264 | # it assumes that sub_fullname($sub) can always be used to find the CV again |
265 | # since we are deleting the glob where the subroutine was originally |
266 | # defined, that assumption no longer holds, so we need to move it |
267 | # elsewhere and point the CV's name to the new glob. |
017bd598 |
268 | $DebuggerRename->( |
269 | $f, |
270 | $sub, |
271 | $cleanee_stash, |
272 | $deleted_stash ||= Package::Stash->new("namespace::clean::deleted::$cleanee"), |
273 | ); |
de673bbf |
274 | } |
d6aecfbf |
275 | |
d64ad6f8 |
276 | my @symbols = map { |
277 | my $name = $_ . $f; |
278 | my $def = $cleanee_stash->get_symbol($name); |
279 | defined($def) ? [$name, $def] : () |
ad4b1a60 |
280 | } '$', '@', '%', ''; |
d64ad6f8 |
281 | |
c86d6ae2 |
282 | $cleanee_stash->remove_glob($f); |
d64ad6f8 |
283 | |
284 | $cleanee_stash->add_symbol(@$_) for @symbols; |
de673bbf |
285 | } |
286 | }; |
53e92ec5 |
287 | |
fcfe7810 |
288 | sub clean_subroutines { |
289 | my ($nc, $cleanee, @subs) = @_; |
290 | $RemoveSubs->($cleanee, {}, @subs); |
291 | } |
292 | |
fa84e425 |
293 | =head2 import |
fcfe7810 |
294 | |
295 | Makes a snapshot of the current defined functions and installs a |
296 | L<B::Hooks::EndOfScope> hook in the current scope to invoke the cleanups. |
297 | |
298 | =cut |
299 | |
de673bbf |
300 | sub import { |
301 | my ($pragma, @args) = @_; |
53e92ec5 |
302 | |
de673bbf |
303 | my (%args, $is_explicit); |
fcfe7810 |
304 | |
305 | ARG: |
306 | while (@args) { |
307 | |
308 | if ($args[0] =~ /^\-/) { |
309 | my $key = shift @args; |
310 | my $value = shift @args; |
311 | $args{ $key } = $value; |
312 | } |
313 | else { |
314 | $is_explicit++; |
315 | last ARG; |
316 | } |
9b680ffe |
317 | } |
318 | |
fcfe7810 |
319 | my $cleanee = exists $args{ -cleanee } ? $args{ -cleanee } : scalar caller; |
de673bbf |
320 | if ($is_explicit) { |
aa2aafae |
321 | on_scope_end { |
de673bbf |
322 | $RemoveSubs->($cleanee, {}, @args); |
aa2aafae |
323 | }; |
9b680ffe |
324 | } |
de673bbf |
325 | else { |
326 | |
327 | # calling class, all current functions and our storage |
328 | my $functions = $pragma->get_functions($cleanee); |
329 | my $store = $pragma->get_class_store($cleanee); |
16d8eca5 |
330 | my $stash = Package::Stash->new($cleanee); |
de673bbf |
331 | |
332 | # except parameter can be array ref or single value |
333 | my %except = map {( $_ => 1 )} ( |
334 | $args{ -except } |
335 | ? ( ref $args{ -except } eq 'ARRAY' ? @{ $args{ -except } } : $args{ -except } ) |
336 | : () |
337 | ); |
338 | |
339 | # register symbols for removal, if they have a CODE entry |
340 | for my $f (keys %$functions) { |
341 | next if $except{ $f }; |
c86d6ae2 |
342 | next unless $stash->has_symbol("&$f"); |
de673bbf |
343 | $store->{remove}{ $f } = 1; |
344 | } |
345 | |
346 | # register EOF handler on first call to import |
347 | unless ($store->{handler_is_installed}) { |
aa2aafae |
348 | on_scope_end { |
de673bbf |
349 | $RemoveSubs->($cleanee, $store, keys %{ $store->{remove} }); |
aa2aafae |
350 | }; |
de673bbf |
351 | $store->{handler_is_installed} = 1; |
352 | } |
353 | |
354 | return 1; |
355 | } |
9b680ffe |
356 | } |
357 | |
fa84e425 |
358 | =head2 unimport |
9b680ffe |
359 | |
360 | This method will be called when you do a |
361 | |
362 | no namespace::clean; |
363 | |
364 | It will start a new section of code that defines functions to clean up. |
365 | |
366 | =cut |
367 | |
368 | sub unimport { |
fcfe7810 |
369 | my ($pragma, %args) = @_; |
9b680ffe |
370 | |
6c0ece9b |
371 | # the calling class, the current functions and our storage |
fcfe7810 |
372 | my $cleanee = exists $args{ -cleanee } ? $args{ -cleanee } : scalar caller; |
9b680ffe |
373 | my $functions = $pragma->get_functions($cleanee); |
374 | my $store = $pragma->get_class_store($cleanee); |
375 | |
6c0ece9b |
376 | # register all unknown previous functions as excluded |
9b680ffe |
377 | for my $f (keys %$functions) { |
378 | next if $store->{remove}{ $f } |
379 | or $store->{exclude}{ $f }; |
380 | $store->{exclude}{ $f } = 1; |
381 | } |
382 | |
383 | return 1; |
384 | } |
385 | |
fa84e425 |
386 | =head2 get_class_store |
9b680ffe |
387 | |
04312494 |
388 | This returns a reference to a hash in a passed package containing |
6c0ece9b |
389 | information about function names included and excluded from removal. |
9b680ffe |
390 | |
391 | =cut |
392 | |
393 | sub get_class_store { |
394 | my ($pragma, $class) = @_; |
16d8eca5 |
395 | my $stash = Package::Stash->new($class); |
5460fcfb |
396 | my $var = "%$STORAGE_VAR"; |
c86d6ae2 |
397 | $stash->add_symbol($var, {}) |
398 | unless $stash->has_symbol($var); |
399 | return $stash->get_symbol($var); |
40aef9d6 |
400 | } |
401 | |
fa84e425 |
402 | =head2 get_functions |
40aef9d6 |
403 | |
404 | Takes a class as argument and returns all currently defined functions |
405 | in it as a hash reference with the function name as key and a typeglob |
406 | reference to the symbol as value. |
407 | |
408 | =cut |
409 | |
410 | sub get_functions { |
411 | my ($pragma, $class) = @_; |
412 | |
16d8eca5 |
413 | my $stash = Package::Stash->new($class); |
40aef9d6 |
414 | return { |
c86d6ae2 |
415 | map { $_ => $stash->get_symbol("&$_") } |
416 | $stash->list_all_symbols('CODE') |
40aef9d6 |
417 | }; |
418 | } |
419 | |
6c0ece9b |
420 | =head1 IMPLEMENTATION DETAILS |
421 | |
04312494 |
422 | This module works through the effect that a |
6c0ece9b |
423 | |
424 | delete $SomePackage::{foo}; |
425 | |
426 | will remove the C<foo> symbol from C<$SomePackage> for run time lookups |
427 | (e.g., method calls) but will leave the entry alive to be called by |
472d4b1e |
428 | already resolved names in the package itself. C<namespace::clean> will |
429 | restore and therefor in effect keep all glob slots that aren't C<CODE>. |
6c0ece9b |
430 | |
431 | A test file has been added to the perl core to ensure that this behaviour |
432 | will be stable in future releases. |
433 | |
434 | Just for completeness sake, if you want to remove the symbol completely, |
435 | use C<undef> instead. |
436 | |
9887772b |
437 | =head1 CAVEATS |
438 | |
439 | This module is fully functional in a pure-perl environment, where |
c8e3fb7e |
440 | L<B::Hooks::EndOfScope> (with the XS dependency L<Variable::Magic>), may |
441 | not be available. However in this case this module falls back to a |
9887772b |
442 | L<tie()|perlfunc/tie> of L<%^H|perlvar/%^H> which may or may not interfere |
443 | with some crack you may be doing independently of namespace::clean. |
444 | |
c8e3fb7e |
445 | If you want to ensure that your codebase is protected from this unlikely |
446 | clash, you need to explicitly depend on L<B::Hooks::EndOfScope>. |
447 | |
40aef9d6 |
448 | =head1 SEE ALSO |
449 | |
705fe1b1 |
450 | L<B::Hooks::EndOfScope> |
40aef9d6 |
451 | |
04312494 |
452 | =head1 THANKS |
40aef9d6 |
453 | |
04312494 |
454 | Many thanks to Matt S Trout for the inspiration on the whole idea. |
40aef9d6 |
455 | |
fa84e425 |
456 | =head1 AUTHORS |
457 | |
458 | =over |
459 | |
460 | =item * |
461 | |
462 | Robert 'phaylon' Sedlacek <rs@474.at> |
463 | |
464 | =item * |
465 | |
466 | Florian Ragwitz <rafl@debian.org> |
467 | |
468 | =item * |
469 | |
470 | Jesse Luehrs <doy@tozt.net> |
471 | |
472 | =item * |
473 | |
474 | Peter Rabbitson <ribasushi@cpan.org> |
475 | |
476 | =back |
477 | |
478 | =head1 COPYRIGHT AND LICENSE |
479 | |
480 | This software is copyright (c) 2011 by Robert 'phaylon' Sedlacek. |
481 | |
482 | This is free software; you can redistribute it and/or modify it under the same terms as the Perl 5 programming language system itself. |
483 | |
40aef9d6 |
484 | =cut |
485 | |
de673bbf |
486 | no warnings; |
487 | 'Danger! Laws of Thermodynamics may not apply.' |