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40aef9d6 |
1 | package namespace::clean; |
40aef9d6 |
2 | |
3 | use warnings; |
4 | use strict; |
5 | |
77b619d7 |
6 | our $VERSION = '0.27'; |
18377f5b |
7 | $VERSION = eval $VERSION if $VERSION =~ /_/; # numify for warning-free dev releases |
8 | |
727a1a2f |
9 | our $STORAGE_VAR = '__NAMESPACE_CLEAN_STORAGE'; |
fa84e425 |
10 | |
727a1a2f |
11 | use B::Hooks::EndOfScope 'on_scope_end'; |
9887772b |
12 | |
acb1d694 |
13 | # FIXME This is a crock of shit, needs to go away |
14 | # currently here to work around https://rt.cpan.org/Ticket/Display.html?id=74151 |
15 | # kill with fire when PS::XS is *finally* fixed |
16 | BEGIN { |
17 | my $provider; |
18 | |
006e9cb4 |
19 | if ( "$]" < 5.008007 ) { |
acb1d694 |
20 | require Package::Stash::PP; |
21 | $provider = 'Package::Stash::PP'; |
22 | } |
23 | else { |
24 | require Package::Stash; |
25 | $provider = 'Package::Stash'; |
26 | } |
27 | eval <<"EOS" or die $@; |
28 | |
29 | sub stash_for (\$) { |
30 | $provider->new(\$_[0]); |
31 | } |
32 | |
33 | 1; |
34 | |
35 | EOS |
36 | } |
40aef9d6 |
37 | |
df4cbc4e |
38 | use namespace::clean::_Util qw( DEBUGGER_NEEDS_CV_RENAME DEBUGGER_NEEDS_CV_PIVOT ); |
80e4e267 |
39 | |
1ae6a568 |
40 | # Built-in debugger CV-retrieval fixups necessary before perl 5.15.5: |
80e4e267 |
41 | # since we are deleting the glob where the subroutine was originally |
1ae6a568 |
42 | # defined, the assumptions below no longer hold. |
80e4e267 |
43 | # |
1ae6a568 |
44 | # In 5.8.9 ~ 5.13.5 (inclusive) the debugger assumes that a CV can |
45 | # always be found under sub_fullname($sub) |
46 | # Workaround: use sub naming to properly name the sub hidden in the package's |
47 | # deleted-stash |
48 | # |
49 | # In the rest of the range ( ... ~ 5.8.8 and 5.13.6 ~ 5.15.4 ) the debugger |
50 | # assumes the name of the glob passed to entersub can be used to find the CV |
51 | # Workaround: realias the original glob to the deleted-stash slot |
52 | # |
aea0cfbe |
53 | # While the errors manifest themselves inside perl5db.pl, they are caused by |
54 | # problems inside the interpreter. If enabled ($^P & 0x01) and existent, |
55 | # the DB::sub sub will be called by the interpreter for any sub call rather |
56 | # that call the sub directly. It is provided the real sub to call in $DB::sub, |
57 | # but the value given has the issues described above. We only have to enable |
58 | # the workaround if DB::sub will be used. |
59 | # |
1ae6a568 |
60 | # Can not tie constants to the current value of $^P directly, |
61 | # as the debugger can be enabled during runtime (kinda dubious) |
80e4e267 |
62 | # |
017bd598 |
63 | |
64 | my $RemoveSubs = sub { |
de673bbf |
65 | my $cleanee = shift; |
66 | my $store = shift; |
acb1d694 |
67 | my $cleanee_stash = stash_for($cleanee); |
017bd598 |
68 | my $deleted_stash; |
69 | |
de673bbf |
70 | SYMBOL: |
71 | for my $f (@_) { |
017bd598 |
72 | |
de673bbf |
73 | # ignore already removed symbols |
74 | next SYMBOL if $store->{exclude}{ $f }; |
de673bbf |
75 | |
017bd598 |
76 | my $sub = $cleanee_stash->get_symbol("&$f") |
77 | or next SYMBOL; |
226432f6 |
78 | |
80e4e267 |
79 | my $need_debugger_fixup = |
df4cbc4e |
80 | ( DEBUGGER_NEEDS_CV_RENAME or DEBUGGER_NEEDS_CV_PIVOT ) |
64c1bcfc |
81 | && |
aea0cfbe |
82 | $^P & 0x01 |
83 | && |
84 | defined &DB::sub |
80e4e267 |
85 | && |
86 | ref(my $globref = \$cleanee_stash->namespace->{$f}) eq 'GLOB' |
1ae6a568 |
87 | && |
88 | ( $deleted_stash ||= stash_for("namespace::clean::deleted::$cleanee") ) |
80e4e267 |
89 | ; |
90 | |
1ae6a568 |
91 | # convince the Perl debugger to work |
92 | # see the comment on top |
93 | if ( DEBUGGER_NEEDS_CV_RENAME and $need_debugger_fixup ) { |
94 | # |
95 | # Note - both get_subname and set_subname are only compiled when CV_RENAME |
96 | # is true ( the 5.8.9 ~ 5.12 range ). On other perls this entire block is |
97 | # constant folded away, and so are the definitions in ::_Util |
98 | # |
99 | # Do not be surprised that they are missing without DEBUGGER_NEEDS_CV_RENAME |
100 | # |
101 | namespace::clean::_Util::get_subname( $sub ) eq ( $cleanee_stash->name . "::$f" ) |
102 | and |
103 | $deleted_stash->add_symbol( |
104 | "&$f", |
105 | namespace::clean::_Util::set_subname( $deleted_stash->name . "::$f", $sub ), |
80e4e267 |
106 | ); |
de673bbf |
107 | } |
1ae6a568 |
108 | elsif ( DEBUGGER_NEEDS_CV_PIVOT and $need_debugger_fixup ) { |
109 | $deleted_stash->add_symbol("&$f", $sub); |
110 | } |
d6aecfbf |
111 | |
d64ad6f8 |
112 | my @symbols = map { |
113 | my $name = $_ . $f; |
114 | my $def = $cleanee_stash->get_symbol($name); |
115 | defined($def) ? [$name, $def] : () |
ad4b1a60 |
116 | } '$', '@', '%', ''; |
d64ad6f8 |
117 | |
c86d6ae2 |
118 | $cleanee_stash->remove_glob($f); |
d64ad6f8 |
119 | |
80e4e267 |
120 | # if this perl needs no renaming trick we need to |
121 | # rename the original glob after the fact |
1ae6a568 |
122 | DEBUGGER_NEEDS_CV_PIVOT |
123 | and |
124 | $need_debugger_fixup |
125 | and |
126 | *$globref = $deleted_stash->namespace->{$f}; |
80e4e267 |
127 | |
d64ad6f8 |
128 | $cleanee_stash->add_symbol(@$_) for @symbols; |
de673bbf |
129 | } |
130 | }; |
53e92ec5 |
131 | |
fcfe7810 |
132 | sub clean_subroutines { |
133 | my ($nc, $cleanee, @subs) = @_; |
134 | $RemoveSubs->($cleanee, {}, @subs); |
135 | } |
136 | |
de673bbf |
137 | sub import { |
138 | my ($pragma, @args) = @_; |
53e92ec5 |
139 | |
de673bbf |
140 | my (%args, $is_explicit); |
fcfe7810 |
141 | |
142 | ARG: |
143 | while (@args) { |
144 | |
145 | if ($args[0] =~ /^\-/) { |
146 | my $key = shift @args; |
147 | my $value = shift @args; |
148 | $args{ $key } = $value; |
149 | } |
150 | else { |
151 | $is_explicit++; |
152 | last ARG; |
153 | } |
9b680ffe |
154 | } |
155 | |
fcfe7810 |
156 | my $cleanee = exists $args{ -cleanee } ? $args{ -cleanee } : scalar caller; |
de673bbf |
157 | if ($is_explicit) { |
aa2aafae |
158 | on_scope_end { |
de673bbf |
159 | $RemoveSubs->($cleanee, {}, @args); |
aa2aafae |
160 | }; |
9b680ffe |
161 | } |
de673bbf |
162 | else { |
163 | |
164 | # calling class, all current functions and our storage |
165 | my $functions = $pragma->get_functions($cleanee); |
166 | my $store = $pragma->get_class_store($cleanee); |
acb1d694 |
167 | my $stash = stash_for($cleanee); |
de673bbf |
168 | |
169 | # except parameter can be array ref or single value |
170 | my %except = map {( $_ => 1 )} ( |
171 | $args{ -except } |
172 | ? ( ref $args{ -except } eq 'ARRAY' ? @{ $args{ -except } } : $args{ -except } ) |
173 | : () |
174 | ); |
175 | |
176 | # register symbols for removal, if they have a CODE entry |
177 | for my $f (keys %$functions) { |
178 | next if $except{ $f }; |
c86d6ae2 |
179 | next unless $stash->has_symbol("&$f"); |
de673bbf |
180 | $store->{remove}{ $f } = 1; |
181 | } |
182 | |
a6b490ab |
183 | on_scope_end { |
184 | $RemoveSubs->($cleanee, $store, keys %{ $store->{remove} }); |
185 | }; |
de673bbf |
186 | |
187 | return 1; |
188 | } |
9b680ffe |
189 | } |
190 | |
9b680ffe |
191 | sub unimport { |
fcfe7810 |
192 | my ($pragma, %args) = @_; |
9b680ffe |
193 | |
6c0ece9b |
194 | # the calling class, the current functions and our storage |
fcfe7810 |
195 | my $cleanee = exists $args{ -cleanee } ? $args{ -cleanee } : scalar caller; |
9b680ffe |
196 | my $functions = $pragma->get_functions($cleanee); |
197 | my $store = $pragma->get_class_store($cleanee); |
198 | |
6c0ece9b |
199 | # register all unknown previous functions as excluded |
9b680ffe |
200 | for my $f (keys %$functions) { |
201 | next if $store->{remove}{ $f } |
202 | or $store->{exclude}{ $f }; |
203 | $store->{exclude}{ $f } = 1; |
204 | } |
205 | |
206 | return 1; |
207 | } |
208 | |
9b680ffe |
209 | sub get_class_store { |
210 | my ($pragma, $class) = @_; |
acb1d694 |
211 | my $stash = stash_for($class); |
5460fcfb |
212 | my $var = "%$STORAGE_VAR"; |
c86d6ae2 |
213 | $stash->add_symbol($var, {}) |
214 | unless $stash->has_symbol($var); |
215 | return $stash->get_symbol($var); |
40aef9d6 |
216 | } |
217 | |
40aef9d6 |
218 | sub get_functions { |
219 | my ($pragma, $class) = @_; |
220 | |
acb1d694 |
221 | my $stash = stash_for($class); |
40aef9d6 |
222 | return { |
c86d6ae2 |
223 | map { $_ => $stash->get_symbol("&$_") } |
224 | $stash->list_all_symbols('CODE') |
40aef9d6 |
225 | }; |
226 | } |
227 | |
b3b7a821 |
228 | 'Danger! Laws of Thermodynamics may not apply.' |
229 | |
230 | __END__ |
231 | |
232 | =head1 NAME |
233 | |
234 | namespace::clean - Keep imports and functions out of your namespace |
235 | |
236 | =head1 SYNOPSIS |
237 | |
238 | package Foo; |
239 | use warnings; |
240 | use strict; |
241 | |
242 | use Carp qw(croak); # 'croak' will be removed |
243 | |
244 | sub bar { 23 } # 'bar' will be removed |
245 | |
246 | # remove all previously defined functions |
247 | use namespace::clean; |
248 | |
249 | sub baz { bar() } # 'baz' still defined, 'bar' still bound |
250 | |
251 | # begin to collection function names from here again |
252 | no namespace::clean; |
253 | |
254 | sub quux { baz() } # 'quux' will be removed |
255 | |
256 | # remove all functions defined after the 'no' unimport |
257 | use namespace::clean; |
258 | |
259 | # Will print: 'No', 'No', 'Yes' and 'No' |
260 | print +(__PACKAGE__->can('croak') ? 'Yes' : 'No'), "\n"; |
261 | print +(__PACKAGE__->can('bar') ? 'Yes' : 'No'), "\n"; |
262 | print +(__PACKAGE__->can('baz') ? 'Yes' : 'No'), "\n"; |
263 | print +(__PACKAGE__->can('quux') ? 'Yes' : 'No'), "\n"; |
264 | |
265 | 1; |
266 | |
267 | =head1 DESCRIPTION |
268 | |
269 | =head2 Keeping packages clean |
270 | |
271 | When you define a function, or import one, into a Perl package, it will |
272 | naturally also be available as a method. This does not per se cause |
273 | problems, but it can complicate subclassing and, for example, plugin |
274 | classes that are included via multiple inheritance by loading them as |
275 | base classes. |
276 | |
277 | The C<namespace::clean> pragma will remove all previously declared or |
278 | imported symbols at the end of the current package's compile cycle. |
279 | Functions called in the package itself will still be bound by their |
280 | name, but they won't show up as methods on your class or instances. |
281 | |
282 | By unimporting via C<no> you can tell C<namespace::clean> to start |
283 | collecting functions for the next C<use namespace::clean;> specification. |
284 | |
285 | You can use the C<-except> flag to tell C<namespace::clean> that you |
286 | don't want it to remove a certain function or method. A common use would |
287 | be a module exporting an C<import> method along with some functions: |
288 | |
289 | use ModuleExportingImport; |
290 | use namespace::clean -except => [qw( import )]; |
291 | |
292 | If you just want to C<-except> a single sub, you can pass it directly. |
293 | For more than one value you have to use an array reference. |
294 | |
253c58bc |
295 | =head3 Late binding caveat |
296 | |
297 | Note that the L<technique used by this module|/IMPLEMENTATION DETAILS> relies |
298 | on perl having resolved all names to actual code references during the |
299 | compilation of a scope. While this is almost always what the interpreter does, |
300 | there are some exceptions, notably the L<sort SUBNAME|perlfunc/sort> style of |
301 | the C<sort> built-in invocation. The following example will not work, because |
302 | C<sort> does not try to resolve the function name to an actual code reference |
303 | until B<runtime>. |
304 | |
305 | use MyApp::Utils 'my_sorter'; |
306 | use namespace::clean; |
307 | |
308 | my @sorted = sort my_sorter @list; |
309 | |
310 | You need to work around this by forcing a compile-time resolution like so: |
311 | |
041ac8b7 |
312 | use MyApp::Utils 'my_sorter'; |
253c58bc |
313 | use namespace::clean; |
314 | |
041ac8b7 |
315 | my $my_sorter_cref = \&my_sorter; |
253c58bc |
316 | |
317 | my @sorted = sort $my_sorter_cref @list; |
318 | |
b3b7a821 |
319 | =head2 Explicitly removing functions when your scope is compiled |
320 | |
321 | It is also possible to explicitly tell C<namespace::clean> what packages |
322 | to remove when the surrounding scope has finished compiling. Here is an |
323 | example: |
324 | |
325 | package Foo; |
326 | use strict; |
327 | |
328 | # blessed NOT available |
329 | |
330 | sub my_class { |
331 | use Scalar::Util qw( blessed ); |
332 | use namespace::clean qw( blessed ); |
333 | |
334 | # blessed available |
335 | return blessed shift; |
336 | } |
337 | |
338 | # blessed NOT available |
339 | |
340 | =head2 Moose |
341 | |
342 | When using C<namespace::clean> together with L<Moose> you want to keep |
343 | the installed C<meta> method. So your classes should look like: |
344 | |
345 | package Foo; |
346 | use Moose; |
347 | use namespace::clean -except => 'meta'; |
348 | ... |
349 | |
350 | Same goes for L<Moose::Role>. |
351 | |
352 | =head2 Cleaning other packages |
353 | |
354 | You can tell C<namespace::clean> that you want to clean up another package |
355 | instead of the one importing. To do this you have to pass in the C<-cleanee> |
356 | option like this: |
357 | |
358 | package My::MooseX::namespace::clean; |
359 | use strict; |
360 | |
361 | use namespace::clean (); # no cleanup, just load |
362 | |
363 | sub import { |
364 | namespace::clean->import( |
365 | -cleanee => scalar(caller), |
366 | -except => 'meta', |
367 | ); |
368 | } |
369 | |
370 | If you don't care about C<namespace::clean>s discover-and-C<-except> logic, and |
371 | just want to remove subroutines, try L</clean_subroutines>. |
372 | |
373 | =head1 METHODS |
374 | |
375 | =head2 clean_subroutines |
376 | |
377 | This exposes the actual subroutine-removal logic. |
378 | |
379 | namespace::clean->clean_subroutines($cleanee, qw( subA subB )); |
380 | |
381 | will remove C<subA> and C<subB> from C<$cleanee>. Note that this will remove the |
382 | subroutines B<immediately> and not wait for scope end. If you want to have this |
383 | effect at a specific time (e.g. C<namespace::clean> acts on scope compile end) |
384 | it is your responsibility to make sure it runs at that time. |
385 | |
386 | =head2 import |
387 | |
388 | Makes a snapshot of the current defined functions and installs a |
389 | L<B::Hooks::EndOfScope> hook in the current scope to invoke the cleanups. |
390 | |
391 | |
392 | =head2 unimport |
393 | |
394 | This method will be called when you do a |
395 | |
396 | no namespace::clean; |
397 | |
398 | It will start a new section of code that defines functions to clean up. |
399 | |
400 | =head2 get_class_store |
401 | |
402 | This returns a reference to a hash in a passed package containing |
403 | information about function names included and excluded from removal. |
404 | |
405 | =head2 get_functions |
406 | |
407 | Takes a class as argument and returns all currently defined functions |
408 | in it as a hash reference with the function name as key and a typeglob |
409 | reference to the symbol as value. |
410 | |
6c0ece9b |
411 | =head1 IMPLEMENTATION DETAILS |
412 | |
04312494 |
413 | This module works through the effect that a |
6c0ece9b |
414 | |
415 | delete $SomePackage::{foo}; |
416 | |
417 | will remove the C<foo> symbol from C<$SomePackage> for run time lookups |
418 | (e.g., method calls) but will leave the entry alive to be called by |
472d4b1e |
419 | already resolved names in the package itself. C<namespace::clean> will |
420 | restore and therefor in effect keep all glob slots that aren't C<CODE>. |
6c0ece9b |
421 | |
422 | A test file has been added to the perl core to ensure that this behaviour |
423 | will be stable in future releases. |
424 | |
425 | Just for completeness sake, if you want to remove the symbol completely, |
426 | use C<undef> instead. |
427 | |
40aef9d6 |
428 | =head1 SEE ALSO |
429 | |
705fe1b1 |
430 | L<B::Hooks::EndOfScope> |
40aef9d6 |
431 | |
04312494 |
432 | =head1 THANKS |
40aef9d6 |
433 | |
04312494 |
434 | Many thanks to Matt S Trout for the inspiration on the whole idea. |
40aef9d6 |
435 | |
fa84e425 |
436 | =head1 AUTHORS |
437 | |
438 | =over |
439 | |
440 | =item * |
441 | |
442 | Robert 'phaylon' Sedlacek <rs@474.at> |
443 | |
444 | =item * |
445 | |
446 | Florian Ragwitz <rafl@debian.org> |
447 | |
448 | =item * |
449 | |
450 | Jesse Luehrs <doy@tozt.net> |
451 | |
452 | =item * |
453 | |
454 | Peter Rabbitson <ribasushi@cpan.org> |
455 | |
b2e54862 |
456 | =item * |
457 | |
458 | Father Chrysostomos <sprout@cpan.org> |
459 | |
fa84e425 |
460 | =back |
461 | |
462 | =head1 COPYRIGHT AND LICENSE |
463 | |
b2e54862 |
464 | This software is copyright (c) 2011 by L</AUTHORS> |
fa84e425 |
465 | |
466 | This is free software; you can redistribute it and/or modify it under the same terms as the Perl 5 programming language system itself. |