Commit | Line | Data |
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 | |
8620b198 |
10 | our $VERSION = '0.21'; |
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 | |
09e4e594 |
94 | =head1 NAME |
95 | |
96 | namespace::clean - Keep imports and functions out of your namespace |
97 | |
40aef9d6 |
98 | =head1 SYNOPSIS |
99 | |
100 | package Foo; |
101 | use warnings; |
102 | use strict; |
103 | |
6c0ece9b |
104 | use Carp qw(croak); # 'croak' will be removed |
40aef9d6 |
105 | |
6c0ece9b |
106 | sub bar { 23 } # 'bar' will be removed |
40aef9d6 |
107 | |
6c0ece9b |
108 | # remove all previously defined functions |
40aef9d6 |
109 | use namespace::clean; |
110 | |
6c0ece9b |
111 | sub baz { bar() } # 'baz' still defined, 'bar' still bound |
40aef9d6 |
112 | |
6c0ece9b |
113 | # begin to collection function names from here again |
9b680ffe |
114 | no namespace::clean; |
115 | |
6c0ece9b |
116 | sub quux { baz() } # 'quux' will be removed |
9b680ffe |
117 | |
6c0ece9b |
118 | # remove all functions defined after the 'no' unimport |
9b680ffe |
119 | use namespace::clean; |
120 | |
6c0ece9b |
121 | # Will print: 'No', 'No', 'Yes' and 'No' |
40aef9d6 |
122 | print +(__PACKAGE__->can('croak') ? 'Yes' : 'No'), "\n"; |
123 | print +(__PACKAGE__->can('bar') ? 'Yes' : 'No'), "\n"; |
124 | print +(__PACKAGE__->can('baz') ? 'Yes' : 'No'), "\n"; |
9b680ffe |
125 | print +(__PACKAGE__->can('quux') ? 'Yes' : 'No'), "\n"; |
40aef9d6 |
126 | |
127 | 1; |
128 | |
129 | =head1 DESCRIPTION |
130 | |
de673bbf |
131 | =head2 Keeping packages clean |
132 | |
40aef9d6 |
133 | When you define a function, or import one, into a Perl package, it will |
134 | naturally also be available as a method. This does not per se cause |
135 | problems, but it can complicate subclassing and, for example, plugin |
04312494 |
136 | classes that are included via multiple inheritance by loading them as |
6c0ece9b |
137 | base classes. |
40aef9d6 |
138 | |
139 | The C<namespace::clean> pragma will remove all previously declared or |
140 | imported symbols at the end of the current package's compile cycle. |
6c0ece9b |
141 | Functions called in the package itself will still be bound by their |
142 | name, but they won't show up as methods on your class or instances. |
143 | |
144 | By unimporting via C<no> you can tell C<namespace::clean> to start |
145 | collecting functions for the next C<use namespace::clean;> specification. |
40aef9d6 |
146 | |
53e92ec5 |
147 | You can use the C<-except> flag to tell C<namespace::clean> that you |
472d4b1e |
148 | don't want it to remove a certain function or method. A common use would |
149 | be a module exporting an C<import> method along with some functions: |
53e92ec5 |
150 | |
151 | use ModuleExportingImport; |
152 | use namespace::clean -except => [qw( import )]; |
153 | |
472d4b1e |
154 | If you just want to C<-except> a single sub, you can pass it directly. |
155 | For more than one value you have to use an array reference. |
156 | |
271df965 |
157 | =head2 Explicitly removing functions when your scope is compiled |
de673bbf |
158 | |
271df965 |
159 | It is also possible to explicitly tell C<namespace::clean> what packages |
de673bbf |
160 | to remove when the surrounding scope has finished compiling. Here is an |
161 | example: |
162 | |
163 | package Foo; |
164 | use strict; |
165 | |
166 | # blessed NOT available |
167 | |
168 | sub my_class { |
169 | use Scalar::Util qw( blessed ); |
170 | use namespace::clean qw( blessed ); |
171 | |
172 | # blessed available |
173 | return blessed shift; |
174 | } |
175 | |
176 | # blessed NOT available |
177 | |
1a1be5dc |
178 | =head2 Moose |
179 | |
180 | When using C<namespace::clean> together with L<Moose> you want to keep |
181 | the installed C<meta> method. So your classes should look like: |
182 | |
183 | package Foo; |
184 | use Moose; |
185 | use namespace::clean -except => 'meta'; |
186 | ... |
187 | |
188 | Same goes for L<Moose::Role>. |
189 | |
fcfe7810 |
190 | =head2 Cleaning other packages |
191 | |
192 | You can tell C<namespace::clean> that you want to clean up another package |
193 | instead of the one importing. To do this you have to pass in the C<-cleanee> |
194 | option like this: |
195 | |
196 | package My::MooseX::namespace::clean; |
197 | use strict; |
198 | |
199 | use namespace::clean (); # no cleanup, just load |
200 | |
201 | sub import { |
202 | namespace::clean->import( |
203 | -cleanee => scalar(caller), |
204 | -except => 'meta', |
205 | ); |
206 | } |
207 | |
208 | If you don't care about C<namespace::clean>s discover-and-C<-except> logic, and |
209 | just want to remove subroutines, try L</clean_subroutines>. |
210 | |
fa84e425 |
211 | =head1 METHODS |
212 | |
213 | =head2 clean_subroutines |
40aef9d6 |
214 | |
fcfe7810 |
215 | This exposes the actual subroutine-removal logic. |
216 | |
217 | namespace::clean->clean_subroutines($cleanee, qw( subA subB )); |
218 | |
219 | will remove C<subA> and C<subB> from C<$cleanee>. Note that this will remove the |
220 | subroutines B<immediately> and not wait for scope end. If you want to have this |
221 | effect at a specific time (e.g. C<namespace::clean> acts on scope compile end) |
222 | it is your responsibility to make sure it runs at that time. |
40aef9d6 |
223 | |
224 | =cut |
225 | |
80e4e267 |
226 | # Constant to optimise away the unused code branches |
227 | use constant RENAME_SUB => $] > 5.008_008_9 && $] < 5.013_006_1; |
228 | { no strict; delete ${__PACKAGE__."::"}{RENAME_SUB} } |
229 | |
230 | # In perl 5.8.9-5.12, it assumes that sub_fullname($sub) can |
231 | # always be used to find the CV again. |
232 | # In perl 5.8.8 and 5.14, it assumes that the name of the glob |
233 | # passed to entersub can be used to find the CV. |
234 | # since we are deleting the glob where the subroutine was originally |
235 | # defined, those assumptions no longer hold. |
236 | # |
237 | # So in 5.8.9-5.12 we need to move it elsewhere and point the |
238 | # CV's name to the new glob. |
239 | # |
240 | # In 5.8.8 and 5.14 we move it elsewhere and rename the |
241 | # original glob by assigning the new glob back to it. |
017bd598 |
242 | my $sub_utils_loaded; |
80e4e267 |
243 | my $DebuggerFixup = sub { |
017bd598 |
244 | my ($f, $sub, $cleanee_stash, $deleted_stash) = @_; |
245 | |
80e4e267 |
246 | if (RENAME_SUB) { |
247 | if (! defined $sub_utils_loaded ) { |
248 | $sub_utils_loaded = do { |
b3279c1c |
249 | |
250 | # when changing version also change in Makefile.PL |
80e4e267 |
251 | my $sn_ver = 0.04; |
252 | eval { require Sub::Name; Sub::Name->VERSION($sn_ver) } |
253 | or die "Sub::Name $sn_ver required when running under -d or equivalent: $@"; |
017bd598 |
254 | |
b3279c1c |
255 | # when changing version also change in Makefile.PL |
80e4e267 |
256 | my $si_ver = 0.04; |
257 | eval { require Sub::Identify; Sub::Identify->VERSION($si_ver) } |
258 | or die "Sub::Identify $si_ver required when running under -d or equivalent: $@"; |
fcfe7810 |
259 | |
80e4e267 |
260 | 1; |
261 | } ? 1 : 0; |
262 | } |
017bd598 |
263 | |
80e4e267 |
264 | if ( Sub::Identify::sub_fullname($sub) eq ($cleanee_stash->name . "::$f") ) { |
265 | my $new_fq = $deleted_stash->name . "::$f"; |
266 | Sub::Name::subname($new_fq, $sub); |
267 | $deleted_stash->add_symbol("&$f", $sub); |
268 | } |
269 | } |
270 | else { |
017bd598 |
271 | $deleted_stash->add_symbol("&$f", $sub); |
272 | } |
273 | }; |
274 | |
275 | my $RemoveSubs = sub { |
de673bbf |
276 | my $cleanee = shift; |
277 | my $store = shift; |
16d8eca5 |
278 | my $cleanee_stash = Package::Stash->new($cleanee); |
017bd598 |
279 | my $deleted_stash; |
280 | |
de673bbf |
281 | SYMBOL: |
282 | for my $f (@_) { |
017bd598 |
283 | |
de673bbf |
284 | # ignore already removed symbols |
285 | next SYMBOL if $store->{exclude}{ $f }; |
de673bbf |
286 | |
017bd598 |
287 | my $sub = $cleanee_stash->get_symbol("&$f") |
288 | or next SYMBOL; |
226432f6 |
289 | |
80e4e267 |
290 | my $need_debugger_fixup = |
291 | $^P |
292 | && |
293 | ref(my $globref = \$cleanee_stash->namespace->{$f}) eq 'GLOB' |
294 | ; |
295 | |
296 | if ($need_debugger_fixup) { |
297 | # convince the Perl debugger to work |
298 | # see the comment on top of $DebuggerFixup |
299 | $DebuggerFixup->( |
300 | $f, |
301 | $sub, |
302 | $cleanee_stash, |
303 | $deleted_stash ||= Package::Stash->new("namespace::clean::deleted::$cleanee"), |
304 | ); |
de673bbf |
305 | } |
d6aecfbf |
306 | |
d64ad6f8 |
307 | my @symbols = map { |
308 | my $name = $_ . $f; |
309 | my $def = $cleanee_stash->get_symbol($name); |
310 | defined($def) ? [$name, $def] : () |
ad4b1a60 |
311 | } '$', '@', '%', ''; |
d64ad6f8 |
312 | |
c86d6ae2 |
313 | $cleanee_stash->remove_glob($f); |
d64ad6f8 |
314 | |
80e4e267 |
315 | # if this perl needs no renaming trick we need to |
316 | # rename the original glob after the fact |
317 | # (see commend of $DebuggerFixup |
318 | if (!RENAME_SUB && $need_debugger_fixup) { |
319 | *$globref = $deleted_stash->namespace->{$f}; |
320 | } |
321 | |
d64ad6f8 |
322 | $cleanee_stash->add_symbol(@$_) for @symbols; |
de673bbf |
323 | } |
324 | }; |
53e92ec5 |
325 | |
fcfe7810 |
326 | sub clean_subroutines { |
327 | my ($nc, $cleanee, @subs) = @_; |
328 | $RemoveSubs->($cleanee, {}, @subs); |
329 | } |
330 | |
fa84e425 |
331 | =head2 import |
fcfe7810 |
332 | |
333 | Makes a snapshot of the current defined functions and installs a |
334 | L<B::Hooks::EndOfScope> hook in the current scope to invoke the cleanups. |
335 | |
336 | =cut |
337 | |
de673bbf |
338 | sub import { |
339 | my ($pragma, @args) = @_; |
53e92ec5 |
340 | |
de673bbf |
341 | my (%args, $is_explicit); |
fcfe7810 |
342 | |
343 | ARG: |
344 | while (@args) { |
345 | |
346 | if ($args[0] =~ /^\-/) { |
347 | my $key = shift @args; |
348 | my $value = shift @args; |
349 | $args{ $key } = $value; |
350 | } |
351 | else { |
352 | $is_explicit++; |
353 | last ARG; |
354 | } |
9b680ffe |
355 | } |
356 | |
fcfe7810 |
357 | my $cleanee = exists $args{ -cleanee } ? $args{ -cleanee } : scalar caller; |
de673bbf |
358 | if ($is_explicit) { |
aa2aafae |
359 | on_scope_end { |
de673bbf |
360 | $RemoveSubs->($cleanee, {}, @args); |
aa2aafae |
361 | }; |
9b680ffe |
362 | } |
de673bbf |
363 | else { |
364 | |
365 | # calling class, all current functions and our storage |
366 | my $functions = $pragma->get_functions($cleanee); |
367 | my $store = $pragma->get_class_store($cleanee); |
16d8eca5 |
368 | my $stash = Package::Stash->new($cleanee); |
de673bbf |
369 | |
370 | # except parameter can be array ref or single value |
371 | my %except = map {( $_ => 1 )} ( |
372 | $args{ -except } |
373 | ? ( ref $args{ -except } eq 'ARRAY' ? @{ $args{ -except } } : $args{ -except } ) |
374 | : () |
375 | ); |
376 | |
377 | # register symbols for removal, if they have a CODE entry |
378 | for my $f (keys %$functions) { |
379 | next if $except{ $f }; |
c86d6ae2 |
380 | next unless $stash->has_symbol("&$f"); |
de673bbf |
381 | $store->{remove}{ $f } = 1; |
382 | } |
383 | |
384 | # register EOF handler on first call to import |
385 | unless ($store->{handler_is_installed}) { |
aa2aafae |
386 | on_scope_end { |
de673bbf |
387 | $RemoveSubs->($cleanee, $store, keys %{ $store->{remove} }); |
aa2aafae |
388 | }; |
de673bbf |
389 | $store->{handler_is_installed} = 1; |
390 | } |
391 | |
392 | return 1; |
393 | } |
9b680ffe |
394 | } |
395 | |
fa84e425 |
396 | =head2 unimport |
9b680ffe |
397 | |
398 | This method will be called when you do a |
399 | |
400 | no namespace::clean; |
401 | |
402 | It will start a new section of code that defines functions to clean up. |
403 | |
404 | =cut |
405 | |
406 | sub unimport { |
fcfe7810 |
407 | my ($pragma, %args) = @_; |
9b680ffe |
408 | |
6c0ece9b |
409 | # the calling class, the current functions and our storage |
fcfe7810 |
410 | my $cleanee = exists $args{ -cleanee } ? $args{ -cleanee } : scalar caller; |
9b680ffe |
411 | my $functions = $pragma->get_functions($cleanee); |
412 | my $store = $pragma->get_class_store($cleanee); |
413 | |
6c0ece9b |
414 | # register all unknown previous functions as excluded |
9b680ffe |
415 | for my $f (keys %$functions) { |
416 | next if $store->{remove}{ $f } |
417 | or $store->{exclude}{ $f }; |
418 | $store->{exclude}{ $f } = 1; |
419 | } |
420 | |
421 | return 1; |
422 | } |
423 | |
fa84e425 |
424 | =head2 get_class_store |
9b680ffe |
425 | |
04312494 |
426 | This returns a reference to a hash in a passed package containing |
6c0ece9b |
427 | information about function names included and excluded from removal. |
9b680ffe |
428 | |
429 | =cut |
430 | |
431 | sub get_class_store { |
432 | my ($pragma, $class) = @_; |
16d8eca5 |
433 | my $stash = Package::Stash->new($class); |
5460fcfb |
434 | my $var = "%$STORAGE_VAR"; |
c86d6ae2 |
435 | $stash->add_symbol($var, {}) |
436 | unless $stash->has_symbol($var); |
437 | return $stash->get_symbol($var); |
40aef9d6 |
438 | } |
439 | |
fa84e425 |
440 | =head2 get_functions |
40aef9d6 |
441 | |
442 | Takes a class as argument and returns all currently defined functions |
443 | in it as a hash reference with the function name as key and a typeglob |
444 | reference to the symbol as value. |
445 | |
446 | =cut |
447 | |
448 | sub get_functions { |
449 | my ($pragma, $class) = @_; |
450 | |
16d8eca5 |
451 | my $stash = Package::Stash->new($class); |
40aef9d6 |
452 | return { |
c86d6ae2 |
453 | map { $_ => $stash->get_symbol("&$_") } |
454 | $stash->list_all_symbols('CODE') |
40aef9d6 |
455 | }; |
456 | } |
457 | |
6c0ece9b |
458 | =head1 IMPLEMENTATION DETAILS |
459 | |
04312494 |
460 | This module works through the effect that a |
6c0ece9b |
461 | |
462 | delete $SomePackage::{foo}; |
463 | |
464 | will remove the C<foo> symbol from C<$SomePackage> for run time lookups |
465 | (e.g., method calls) but will leave the entry alive to be called by |
472d4b1e |
466 | already resolved names in the package itself. C<namespace::clean> will |
467 | restore and therefor in effect keep all glob slots that aren't C<CODE>. |
6c0ece9b |
468 | |
469 | A test file has been added to the perl core to ensure that this behaviour |
470 | will be stable in future releases. |
471 | |
472 | Just for completeness sake, if you want to remove the symbol completely, |
473 | use C<undef> instead. |
474 | |
9887772b |
475 | =head1 CAVEATS |
476 | |
477 | This module is fully functional in a pure-perl environment, where |
c8e3fb7e |
478 | L<B::Hooks::EndOfScope> (with the XS dependency L<Variable::Magic>), may |
479 | not be available. However in this case this module falls back to a |
9887772b |
480 | L<tie()|perlfunc/tie> of L<%^H|perlvar/%^H> which may or may not interfere |
481 | with some crack you may be doing independently of namespace::clean. |
482 | |
c8e3fb7e |
483 | If you want to ensure that your codebase is protected from this unlikely |
484 | clash, you need to explicitly depend on L<B::Hooks::EndOfScope>. |
485 | |
40aef9d6 |
486 | =head1 SEE ALSO |
487 | |
705fe1b1 |
488 | L<B::Hooks::EndOfScope> |
40aef9d6 |
489 | |
04312494 |
490 | =head1 THANKS |
40aef9d6 |
491 | |
04312494 |
492 | Many thanks to Matt S Trout for the inspiration on the whole idea. |
40aef9d6 |
493 | |
fa84e425 |
494 | =head1 AUTHORS |
495 | |
496 | =over |
497 | |
498 | =item * |
499 | |
500 | Robert 'phaylon' Sedlacek <rs@474.at> |
501 | |
502 | =item * |
503 | |
504 | Florian Ragwitz <rafl@debian.org> |
505 | |
506 | =item * |
507 | |
508 | Jesse Luehrs <doy@tozt.net> |
509 | |
510 | =item * |
511 | |
512 | Peter Rabbitson <ribasushi@cpan.org> |
513 | |
514 | =back |
515 | |
516 | =head1 COPYRIGHT AND LICENSE |
517 | |
518 | This software is copyright (c) 2011 by Robert 'phaylon' Sedlacek. |
519 | |
520 | This is free software; you can redistribute it and/or modify it under the same terms as the Perl 5 programming language system itself. |
521 | |
40aef9d6 |
522 | =cut |
523 | |
de673bbf |
524 | no warnings; |
525 | 'Danger! Laws of Thermodynamics may not apply.' |