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1 | package namespace::clean; |
40aef9d6 |
2 | |
3 | use warnings; |
4 | use strict; |
5 | |
9887772b |
6 | use Package::Stash; |
40aef9d6 |
7 | |
33f4d157 |
8 | our $VERSION = '0.24'; |
727a1a2f |
9 | our $STORAGE_VAR = '__NAMESPACE_CLEAN_STORAGE'; |
fa84e425 |
10 | |
727a1a2f |
11 | use B::Hooks::EndOfScope 'on_scope_end'; |
9887772b |
12 | |
09e4e594 |
13 | =head1 NAME |
14 | |
15 | namespace::clean - Keep imports and functions out of your namespace |
16 | |
40aef9d6 |
17 | =head1 SYNOPSIS |
18 | |
19 | package Foo; |
20 | use warnings; |
21 | use strict; |
22 | |
6c0ece9b |
23 | use Carp qw(croak); # 'croak' will be removed |
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24 | |
6c0ece9b |
25 | sub bar { 23 } # 'bar' will be removed |
40aef9d6 |
26 | |
6c0ece9b |
27 | # remove all previously defined functions |
40aef9d6 |
28 | use namespace::clean; |
29 | |
6c0ece9b |
30 | sub baz { bar() } # 'baz' still defined, 'bar' still bound |
40aef9d6 |
31 | |
6c0ece9b |
32 | # begin to collection function names from here again |
9b680ffe |
33 | no namespace::clean; |
34 | |
6c0ece9b |
35 | sub quux { baz() } # 'quux' will be removed |
9b680ffe |
36 | |
6c0ece9b |
37 | # remove all functions defined after the 'no' unimport |
9b680ffe |
38 | use namespace::clean; |
39 | |
6c0ece9b |
40 | # Will print: 'No', 'No', 'Yes' and 'No' |
40aef9d6 |
41 | print +(__PACKAGE__->can('croak') ? 'Yes' : 'No'), "\n"; |
42 | print +(__PACKAGE__->can('bar') ? 'Yes' : 'No'), "\n"; |
43 | print +(__PACKAGE__->can('baz') ? 'Yes' : 'No'), "\n"; |
9b680ffe |
44 | print +(__PACKAGE__->can('quux') ? 'Yes' : 'No'), "\n"; |
40aef9d6 |
45 | |
46 | 1; |
47 | |
48 | =head1 DESCRIPTION |
49 | |
de673bbf |
50 | =head2 Keeping packages clean |
51 | |
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52 | When you define a function, or import one, into a Perl package, it will |
53 | naturally also be available as a method. This does not per se cause |
54 | problems, but it can complicate subclassing and, for example, plugin |
04312494 |
55 | classes that are included via multiple inheritance by loading them as |
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56 | base classes. |
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57 | |
58 | The C<namespace::clean> pragma will remove all previously declared or |
59 | imported symbols at the end of the current package's compile cycle. |
6c0ece9b |
60 | Functions called in the package itself will still be bound by their |
61 | name, but they won't show up as methods on your class or instances. |
62 | |
63 | By unimporting via C<no> you can tell C<namespace::clean> to start |
64 | collecting functions for the next C<use namespace::clean;> specification. |
40aef9d6 |
65 | |
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66 | You can use the C<-except> flag to tell C<namespace::clean> that you |
472d4b1e |
67 | don't want it to remove a certain function or method. A common use would |
68 | be a module exporting an C<import> method along with some functions: |
53e92ec5 |
69 | |
70 | use ModuleExportingImport; |
71 | use namespace::clean -except => [qw( import )]; |
72 | |
472d4b1e |
73 | If you just want to C<-except> a single sub, you can pass it directly. |
74 | For more than one value you have to use an array reference. |
75 | |
271df965 |
76 | =head2 Explicitly removing functions when your scope is compiled |
de673bbf |
77 | |
271df965 |
78 | It is also possible to explicitly tell C<namespace::clean> what packages |
de673bbf |
79 | to remove when the surrounding scope has finished compiling. Here is an |
80 | example: |
81 | |
82 | package Foo; |
83 | use strict; |
84 | |
85 | # blessed NOT available |
86 | |
87 | sub my_class { |
88 | use Scalar::Util qw( blessed ); |
89 | use namespace::clean qw( blessed ); |
90 | |
91 | # blessed available |
92 | return blessed shift; |
93 | } |
94 | |
95 | # blessed NOT available |
96 | |
1a1be5dc |
97 | =head2 Moose |
98 | |
99 | When using C<namespace::clean> together with L<Moose> you want to keep |
100 | the installed C<meta> method. So your classes should look like: |
101 | |
102 | package Foo; |
103 | use Moose; |
104 | use namespace::clean -except => 'meta'; |
105 | ... |
106 | |
107 | Same goes for L<Moose::Role>. |
108 | |
fcfe7810 |
109 | =head2 Cleaning other packages |
110 | |
111 | You can tell C<namespace::clean> that you want to clean up another package |
112 | instead of the one importing. To do this you have to pass in the C<-cleanee> |
113 | option like this: |
114 | |
115 | package My::MooseX::namespace::clean; |
116 | use strict; |
117 | |
118 | use namespace::clean (); # no cleanup, just load |
119 | |
120 | sub import { |
121 | namespace::clean->import( |
122 | -cleanee => scalar(caller), |
123 | -except => 'meta', |
124 | ); |
125 | } |
126 | |
127 | If you don't care about C<namespace::clean>s discover-and-C<-except> logic, and |
128 | just want to remove subroutines, try L</clean_subroutines>. |
129 | |
fa84e425 |
130 | =head1 METHODS |
131 | |
132 | =head2 clean_subroutines |
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133 | |
fcfe7810 |
134 | This exposes the actual subroutine-removal logic. |
135 | |
136 | namespace::clean->clean_subroutines($cleanee, qw( subA subB )); |
137 | |
138 | will remove C<subA> and C<subB> from C<$cleanee>. Note that this will remove the |
139 | subroutines B<immediately> and not wait for scope end. If you want to have this |
140 | effect at a specific time (e.g. C<namespace::clean> acts on scope compile end) |
141 | it is your responsibility to make sure it runs at that time. |
40aef9d6 |
142 | |
143 | =cut |
144 | |
80e4e267 |
145 | # Constant to optimise away the unused code branches |
64c1bcfc |
146 | use constant FIXUP_NEEDED => $] < 5.015_005_1; |
b927cca7 |
147 | use constant FIXUP_RENAME_SUB => $] > 5.008_008_9 && $] < 5.013_005_1; |
64c1bcfc |
148 | { |
149 | no strict; |
150 | delete ${__PACKAGE__."::"}{FIXUP_NEEDED}; |
151 | delete ${__PACKAGE__."::"}{FIXUP_RENAME_SUB}; |
152 | } |
80e4e267 |
153 | |
64c1bcfc |
154 | # Debugger fixup necessary before perl 5.15.5 |
155 | # |
80e4e267 |
156 | # In perl 5.8.9-5.12, it assumes that sub_fullname($sub) can |
157 | # always be used to find the CV again. |
158 | # In perl 5.8.8 and 5.14, it assumes that the name of the glob |
159 | # passed to entersub can be used to find the CV. |
160 | # since we are deleting the glob where the subroutine was originally |
161 | # defined, those assumptions no longer hold. |
162 | # |
163 | # So in 5.8.9-5.12 we need to move it elsewhere and point the |
164 | # CV's name to the new glob. |
165 | # |
166 | # In 5.8.8 and 5.14 we move it elsewhere and rename the |
167 | # original glob by assigning the new glob back to it. |
017bd598 |
168 | my $sub_utils_loaded; |
80e4e267 |
169 | my $DebuggerFixup = sub { |
017bd598 |
170 | my ($f, $sub, $cleanee_stash, $deleted_stash) = @_; |
171 | |
64c1bcfc |
172 | if (FIXUP_RENAME_SUB) { |
80e4e267 |
173 | if (! defined $sub_utils_loaded ) { |
174 | $sub_utils_loaded = do { |
b3279c1c |
175 | |
176 | # when changing version also change in Makefile.PL |
80e4e267 |
177 | my $sn_ver = 0.04; |
178 | eval { require Sub::Name; Sub::Name->VERSION($sn_ver) } |
179 | or die "Sub::Name $sn_ver required when running under -d or equivalent: $@"; |
017bd598 |
180 | |
b3279c1c |
181 | # when changing version also change in Makefile.PL |
80e4e267 |
182 | my $si_ver = 0.04; |
183 | eval { require Sub::Identify; Sub::Identify->VERSION($si_ver) } |
184 | or die "Sub::Identify $si_ver required when running under -d or equivalent: $@"; |
fcfe7810 |
185 | |
80e4e267 |
186 | 1; |
187 | } ? 1 : 0; |
188 | } |
017bd598 |
189 | |
80e4e267 |
190 | if ( Sub::Identify::sub_fullname($sub) eq ($cleanee_stash->name . "::$f") ) { |
191 | my $new_fq = $deleted_stash->name . "::$f"; |
192 | Sub::Name::subname($new_fq, $sub); |
193 | $deleted_stash->add_symbol("&$f", $sub); |
194 | } |
195 | } |
196 | else { |
017bd598 |
197 | $deleted_stash->add_symbol("&$f", $sub); |
198 | } |
199 | }; |
200 | |
201 | my $RemoveSubs = sub { |
de673bbf |
202 | my $cleanee = shift; |
203 | my $store = shift; |
16d8eca5 |
204 | my $cleanee_stash = Package::Stash->new($cleanee); |
017bd598 |
205 | my $deleted_stash; |
206 | |
de673bbf |
207 | SYMBOL: |
208 | for my $f (@_) { |
017bd598 |
209 | |
de673bbf |
210 | # ignore already removed symbols |
211 | next SYMBOL if $store->{exclude}{ $f }; |
de673bbf |
212 | |
017bd598 |
213 | my $sub = $cleanee_stash->get_symbol("&$f") |
214 | or next SYMBOL; |
226432f6 |
215 | |
80e4e267 |
216 | my $need_debugger_fixup = |
64c1bcfc |
217 | FIXUP_NEEDED |
218 | && |
80e4e267 |
219 | $^P |
220 | && |
221 | ref(my $globref = \$cleanee_stash->namespace->{$f}) eq 'GLOB' |
222 | ; |
223 | |
64c1bcfc |
224 | if (FIXUP_NEEDED && $need_debugger_fixup) { |
80e4e267 |
225 | # convince the Perl debugger to work |
226 | # see the comment on top of $DebuggerFixup |
227 | $DebuggerFixup->( |
228 | $f, |
229 | $sub, |
230 | $cleanee_stash, |
231 | $deleted_stash ||= Package::Stash->new("namespace::clean::deleted::$cleanee"), |
232 | ); |
de673bbf |
233 | } |
d6aecfbf |
234 | |
d64ad6f8 |
235 | my @symbols = map { |
236 | my $name = $_ . $f; |
237 | my $def = $cleanee_stash->get_symbol($name); |
238 | defined($def) ? [$name, $def] : () |
ad4b1a60 |
239 | } '$', '@', '%', ''; |
d64ad6f8 |
240 | |
c86d6ae2 |
241 | $cleanee_stash->remove_glob($f); |
d64ad6f8 |
242 | |
80e4e267 |
243 | # if this perl needs no renaming trick we need to |
244 | # rename the original glob after the fact |
245 | # (see commend of $DebuggerFixup |
64c1bcfc |
246 | if (FIXUP_NEEDED && !FIXUP_RENAME_SUB && $need_debugger_fixup) { |
80e4e267 |
247 | *$globref = $deleted_stash->namespace->{$f}; |
248 | } |
249 | |
d64ad6f8 |
250 | $cleanee_stash->add_symbol(@$_) for @symbols; |
de673bbf |
251 | } |
252 | }; |
53e92ec5 |
253 | |
fcfe7810 |
254 | sub clean_subroutines { |
255 | my ($nc, $cleanee, @subs) = @_; |
256 | $RemoveSubs->($cleanee, {}, @subs); |
257 | } |
258 | |
fa84e425 |
259 | =head2 import |
fcfe7810 |
260 | |
261 | Makes a snapshot of the current defined functions and installs a |
262 | L<B::Hooks::EndOfScope> hook in the current scope to invoke the cleanups. |
263 | |
264 | =cut |
265 | |
de673bbf |
266 | sub import { |
267 | my ($pragma, @args) = @_; |
53e92ec5 |
268 | |
de673bbf |
269 | my (%args, $is_explicit); |
fcfe7810 |
270 | |
271 | ARG: |
272 | while (@args) { |
273 | |
274 | if ($args[0] =~ /^\-/) { |
275 | my $key = shift @args; |
276 | my $value = shift @args; |
277 | $args{ $key } = $value; |
278 | } |
279 | else { |
280 | $is_explicit++; |
281 | last ARG; |
282 | } |
9b680ffe |
283 | } |
284 | |
fcfe7810 |
285 | my $cleanee = exists $args{ -cleanee } ? $args{ -cleanee } : scalar caller; |
de673bbf |
286 | if ($is_explicit) { |
aa2aafae |
287 | on_scope_end { |
de673bbf |
288 | $RemoveSubs->($cleanee, {}, @args); |
aa2aafae |
289 | }; |
9b680ffe |
290 | } |
de673bbf |
291 | else { |
292 | |
293 | # calling class, all current functions and our storage |
294 | my $functions = $pragma->get_functions($cleanee); |
295 | my $store = $pragma->get_class_store($cleanee); |
16d8eca5 |
296 | my $stash = Package::Stash->new($cleanee); |
de673bbf |
297 | |
298 | # except parameter can be array ref or single value |
299 | my %except = map {( $_ => 1 )} ( |
300 | $args{ -except } |
301 | ? ( ref $args{ -except } eq 'ARRAY' ? @{ $args{ -except } } : $args{ -except } ) |
302 | : () |
303 | ); |
304 | |
305 | # register symbols for removal, if they have a CODE entry |
306 | for my $f (keys %$functions) { |
307 | next if $except{ $f }; |
c86d6ae2 |
308 | next unless $stash->has_symbol("&$f"); |
de673bbf |
309 | $store->{remove}{ $f } = 1; |
310 | } |
311 | |
312 | # register EOF handler on first call to import |
313 | unless ($store->{handler_is_installed}) { |
aa2aafae |
314 | on_scope_end { |
de673bbf |
315 | $RemoveSubs->($cleanee, $store, keys %{ $store->{remove} }); |
aa2aafae |
316 | }; |
de673bbf |
317 | $store->{handler_is_installed} = 1; |
318 | } |
319 | |
320 | return 1; |
321 | } |
9b680ffe |
322 | } |
323 | |
fa84e425 |
324 | =head2 unimport |
9b680ffe |
325 | |
326 | This method will be called when you do a |
327 | |
328 | no namespace::clean; |
329 | |
330 | It will start a new section of code that defines functions to clean up. |
331 | |
332 | =cut |
333 | |
334 | sub unimport { |
fcfe7810 |
335 | my ($pragma, %args) = @_; |
9b680ffe |
336 | |
6c0ece9b |
337 | # the calling class, the current functions and our storage |
fcfe7810 |
338 | my $cleanee = exists $args{ -cleanee } ? $args{ -cleanee } : scalar caller; |
9b680ffe |
339 | my $functions = $pragma->get_functions($cleanee); |
340 | my $store = $pragma->get_class_store($cleanee); |
341 | |
6c0ece9b |
342 | # register all unknown previous functions as excluded |
9b680ffe |
343 | for my $f (keys %$functions) { |
344 | next if $store->{remove}{ $f } |
345 | or $store->{exclude}{ $f }; |
346 | $store->{exclude}{ $f } = 1; |
347 | } |
348 | |
349 | return 1; |
350 | } |
351 | |
fa84e425 |
352 | =head2 get_class_store |
9b680ffe |
353 | |
04312494 |
354 | This returns a reference to a hash in a passed package containing |
6c0ece9b |
355 | information about function names included and excluded from removal. |
9b680ffe |
356 | |
357 | =cut |
358 | |
359 | sub get_class_store { |
360 | my ($pragma, $class) = @_; |
16d8eca5 |
361 | my $stash = Package::Stash->new($class); |
5460fcfb |
362 | my $var = "%$STORAGE_VAR"; |
c86d6ae2 |
363 | $stash->add_symbol($var, {}) |
364 | unless $stash->has_symbol($var); |
365 | return $stash->get_symbol($var); |
40aef9d6 |
366 | } |
367 | |
fa84e425 |
368 | =head2 get_functions |
40aef9d6 |
369 | |
370 | Takes a class as argument and returns all currently defined functions |
371 | in it as a hash reference with the function name as key and a typeglob |
372 | reference to the symbol as value. |
373 | |
374 | =cut |
375 | |
376 | sub get_functions { |
377 | my ($pragma, $class) = @_; |
378 | |
16d8eca5 |
379 | my $stash = Package::Stash->new($class); |
40aef9d6 |
380 | return { |
c86d6ae2 |
381 | map { $_ => $stash->get_symbol("&$_") } |
382 | $stash->list_all_symbols('CODE') |
40aef9d6 |
383 | }; |
384 | } |
385 | |
6c0ece9b |
386 | =head1 IMPLEMENTATION DETAILS |
387 | |
04312494 |
388 | This module works through the effect that a |
6c0ece9b |
389 | |
390 | delete $SomePackage::{foo}; |
391 | |
392 | will remove the C<foo> symbol from C<$SomePackage> for run time lookups |
393 | (e.g., method calls) but will leave the entry alive to be called by |
472d4b1e |
394 | already resolved names in the package itself. C<namespace::clean> will |
395 | restore and therefor in effect keep all glob slots that aren't C<CODE>. |
6c0ece9b |
396 | |
397 | A test file has been added to the perl core to ensure that this behaviour |
398 | will be stable in future releases. |
399 | |
400 | Just for completeness sake, if you want to remove the symbol completely, |
401 | use C<undef> instead. |
402 | |
40aef9d6 |
403 | =head1 SEE ALSO |
404 | |
705fe1b1 |
405 | L<B::Hooks::EndOfScope> |
40aef9d6 |
406 | |
04312494 |
407 | =head1 THANKS |
40aef9d6 |
408 | |
04312494 |
409 | Many thanks to Matt S Trout for the inspiration on the whole idea. |
40aef9d6 |
410 | |
fa84e425 |
411 | =head1 AUTHORS |
412 | |
413 | =over |
414 | |
415 | =item * |
416 | |
417 | Robert 'phaylon' Sedlacek <rs@474.at> |
418 | |
419 | =item * |
420 | |
421 | Florian Ragwitz <rafl@debian.org> |
422 | |
423 | =item * |
424 | |
425 | Jesse Luehrs <doy@tozt.net> |
426 | |
427 | =item * |
428 | |
429 | Peter Rabbitson <ribasushi@cpan.org> |
430 | |
b2e54862 |
431 | =item * |
432 | |
433 | Father Chrysostomos <sprout@cpan.org> |
434 | |
fa84e425 |
435 | =back |
436 | |
437 | =head1 COPYRIGHT AND LICENSE |
438 | |
b2e54862 |
439 | This software is copyright (c) 2011 by L</AUTHORS> |
fa84e425 |
440 | |
441 | This is free software; you can redistribute it and/or modify it under the same terms as the Perl 5 programming language system itself. |
442 | |
40aef9d6 |
443 | =cut |
444 | |
de673bbf |
445 | no warnings; |
446 | 'Danger! Laws of Thermodynamics may not apply.' |