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1 | package namespace::clean; |
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2 | |
3 | use warnings; |
4 | use strict; |
5 | |
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6 | our $VERSION = '0.25'; |
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7 | our $STORAGE_VAR = '__NAMESPACE_CLEAN_STORAGE'; |
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8 | |
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9 | use B::Hooks::EndOfScope 'on_scope_end'; |
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10 | |
acb1d694 |
11 | # FIXME This is a crock of shit, needs to go away |
12 | # currently here to work around https://rt.cpan.org/Ticket/Display.html?id=74151 |
13 | # kill with fire when PS::XS is *finally* fixed |
14 | BEGIN { |
15 | my $provider; |
16 | |
17 | if ( $] < 5.008007 ) { |
18 | require Package::Stash::PP; |
19 | $provider = 'Package::Stash::PP'; |
20 | } |
21 | else { |
22 | require Package::Stash; |
23 | $provider = 'Package::Stash'; |
24 | } |
25 | eval <<"EOS" or die $@; |
26 | |
27 | sub stash_for (\$) { |
28 | $provider->new(\$_[0]); |
29 | } |
30 | |
31 | 1; |
32 | |
33 | EOS |
34 | } |
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35 | |
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36 | use namespace::clean::_Util qw( DEBUGGER_NEEDS_CV_RENAME DEBUGGER_NEEDS_CV_PIVOT ); |
80e4e267 |
37 | |
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38 | # Built-in debugger CV-retrieval fixups necessary before perl 5.15.5: |
80e4e267 |
39 | # since we are deleting the glob where the subroutine was originally |
1ae6a568 |
40 | # defined, the assumptions below no longer hold. |
80e4e267 |
41 | # |
1ae6a568 |
42 | # In 5.8.9 ~ 5.13.5 (inclusive) the debugger assumes that a CV can |
43 | # always be found under sub_fullname($sub) |
44 | # Workaround: use sub naming to properly name the sub hidden in the package's |
45 | # deleted-stash |
46 | # |
47 | # In the rest of the range ( ... ~ 5.8.8 and 5.13.6 ~ 5.15.4 ) the debugger |
48 | # assumes the name of the glob passed to entersub can be used to find the CV |
49 | # Workaround: realias the original glob to the deleted-stash slot |
50 | # |
51 | # Can not tie constants to the current value of $^P directly, |
52 | # as the debugger can be enabled during runtime (kinda dubious) |
80e4e267 |
53 | # |
017bd598 |
54 | |
55 | my $RemoveSubs = sub { |
de673bbf |
56 | my $cleanee = shift; |
57 | my $store = shift; |
acb1d694 |
58 | my $cleanee_stash = stash_for($cleanee); |
017bd598 |
59 | my $deleted_stash; |
60 | |
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61 | SYMBOL: |
62 | for my $f (@_) { |
017bd598 |
63 | |
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64 | # ignore already removed symbols |
65 | next SYMBOL if $store->{exclude}{ $f }; |
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66 | |
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67 | my $sub = $cleanee_stash->get_symbol("&$f") |
68 | or next SYMBOL; |
226432f6 |
69 | |
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70 | my $need_debugger_fixup = |
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71 | ( DEBUGGER_NEEDS_CV_RENAME or DEBUGGER_NEEDS_CV_PIVOT ) |
64c1bcfc |
72 | && |
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73 | $^P |
74 | && |
75 | ref(my $globref = \$cleanee_stash->namespace->{$f}) eq 'GLOB' |
1ae6a568 |
76 | && |
77 | ( $deleted_stash ||= stash_for("namespace::clean::deleted::$cleanee") ) |
80e4e267 |
78 | ; |
79 | |
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80 | # convince the Perl debugger to work |
81 | # see the comment on top |
82 | if ( DEBUGGER_NEEDS_CV_RENAME and $need_debugger_fixup ) { |
83 | # |
84 | # Note - both get_subname and set_subname are only compiled when CV_RENAME |
85 | # is true ( the 5.8.9 ~ 5.12 range ). On other perls this entire block is |
86 | # constant folded away, and so are the definitions in ::_Util |
87 | # |
88 | # Do not be surprised that they are missing without DEBUGGER_NEEDS_CV_RENAME |
89 | # |
90 | namespace::clean::_Util::get_subname( $sub ) eq ( $cleanee_stash->name . "::$f" ) |
91 | and |
92 | $deleted_stash->add_symbol( |
93 | "&$f", |
94 | namespace::clean::_Util::set_subname( $deleted_stash->name . "::$f", $sub ), |
80e4e267 |
95 | ); |
de673bbf |
96 | } |
1ae6a568 |
97 | elsif ( DEBUGGER_NEEDS_CV_PIVOT and $need_debugger_fixup ) { |
98 | $deleted_stash->add_symbol("&$f", $sub); |
99 | } |
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100 | |
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101 | my @symbols = map { |
102 | my $name = $_ . $f; |
103 | my $def = $cleanee_stash->get_symbol($name); |
104 | defined($def) ? [$name, $def] : () |
ad4b1a60 |
105 | } '$', '@', '%', ''; |
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106 | |
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107 | $cleanee_stash->remove_glob($f); |
d64ad6f8 |
108 | |
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109 | # if this perl needs no renaming trick we need to |
110 | # rename the original glob after the fact |
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111 | DEBUGGER_NEEDS_CV_PIVOT |
112 | and |
113 | $need_debugger_fixup |
114 | and |
115 | *$globref = $deleted_stash->namespace->{$f}; |
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116 | |
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117 | $cleanee_stash->add_symbol(@$_) for @symbols; |
de673bbf |
118 | } |
119 | }; |
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120 | |
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121 | sub clean_subroutines { |
122 | my ($nc, $cleanee, @subs) = @_; |
123 | $RemoveSubs->($cleanee, {}, @subs); |
124 | } |
125 | |
de673bbf |
126 | sub import { |
127 | my ($pragma, @args) = @_; |
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128 | |
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129 | my (%args, $is_explicit); |
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130 | |
131 | ARG: |
132 | while (@args) { |
133 | |
134 | if ($args[0] =~ /^\-/) { |
135 | my $key = shift @args; |
136 | my $value = shift @args; |
137 | $args{ $key } = $value; |
138 | } |
139 | else { |
140 | $is_explicit++; |
141 | last ARG; |
142 | } |
9b680ffe |
143 | } |
144 | |
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145 | my $cleanee = exists $args{ -cleanee } ? $args{ -cleanee } : scalar caller; |
de673bbf |
146 | if ($is_explicit) { |
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147 | on_scope_end { |
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148 | $RemoveSubs->($cleanee, {}, @args); |
aa2aafae |
149 | }; |
9b680ffe |
150 | } |
de673bbf |
151 | else { |
152 | |
153 | # calling class, all current functions and our storage |
154 | my $functions = $pragma->get_functions($cleanee); |
155 | my $store = $pragma->get_class_store($cleanee); |
acb1d694 |
156 | my $stash = stash_for($cleanee); |
de673bbf |
157 | |
158 | # except parameter can be array ref or single value |
159 | my %except = map {( $_ => 1 )} ( |
160 | $args{ -except } |
161 | ? ( ref $args{ -except } eq 'ARRAY' ? @{ $args{ -except } } : $args{ -except } ) |
162 | : () |
163 | ); |
164 | |
165 | # register symbols for removal, if they have a CODE entry |
166 | for my $f (keys %$functions) { |
167 | next if $except{ $f }; |
c86d6ae2 |
168 | next unless $stash->has_symbol("&$f"); |
de673bbf |
169 | $store->{remove}{ $f } = 1; |
170 | } |
171 | |
172 | # register EOF handler on first call to import |
173 | unless ($store->{handler_is_installed}) { |
aa2aafae |
174 | on_scope_end { |
de673bbf |
175 | $RemoveSubs->($cleanee, $store, keys %{ $store->{remove} }); |
aa2aafae |
176 | }; |
de673bbf |
177 | $store->{handler_is_installed} = 1; |
178 | } |
179 | |
180 | return 1; |
181 | } |
9b680ffe |
182 | } |
183 | |
9b680ffe |
184 | sub unimport { |
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185 | my ($pragma, %args) = @_; |
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186 | |
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187 | # the calling class, the current functions and our storage |
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188 | my $cleanee = exists $args{ -cleanee } ? $args{ -cleanee } : scalar caller; |
9b680ffe |
189 | my $functions = $pragma->get_functions($cleanee); |
190 | my $store = $pragma->get_class_store($cleanee); |
191 | |
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192 | # register all unknown previous functions as excluded |
9b680ffe |
193 | for my $f (keys %$functions) { |
194 | next if $store->{remove}{ $f } |
195 | or $store->{exclude}{ $f }; |
196 | $store->{exclude}{ $f } = 1; |
197 | } |
198 | |
199 | return 1; |
200 | } |
201 | |
9b680ffe |
202 | sub get_class_store { |
203 | my ($pragma, $class) = @_; |
acb1d694 |
204 | my $stash = stash_for($class); |
5460fcfb |
205 | my $var = "%$STORAGE_VAR"; |
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206 | $stash->add_symbol($var, {}) |
207 | unless $stash->has_symbol($var); |
208 | return $stash->get_symbol($var); |
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209 | } |
210 | |
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211 | sub get_functions { |
212 | my ($pragma, $class) = @_; |
213 | |
acb1d694 |
214 | my $stash = stash_for($class); |
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215 | return { |
c86d6ae2 |
216 | map { $_ => $stash->get_symbol("&$_") } |
217 | $stash->list_all_symbols('CODE') |
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218 | }; |
219 | } |
220 | |
b3b7a821 |
221 | 'Danger! Laws of Thermodynamics may not apply.' |
222 | |
223 | __END__ |
224 | |
225 | =head1 NAME |
226 | |
227 | namespace::clean - Keep imports and functions out of your namespace |
228 | |
229 | =head1 SYNOPSIS |
230 | |
231 | package Foo; |
232 | use warnings; |
233 | use strict; |
234 | |
235 | use Carp qw(croak); # 'croak' will be removed |
236 | |
237 | sub bar { 23 } # 'bar' will be removed |
238 | |
239 | # remove all previously defined functions |
240 | use namespace::clean; |
241 | |
242 | sub baz { bar() } # 'baz' still defined, 'bar' still bound |
243 | |
244 | # begin to collection function names from here again |
245 | no namespace::clean; |
246 | |
247 | sub quux { baz() } # 'quux' will be removed |
248 | |
249 | # remove all functions defined after the 'no' unimport |
250 | use namespace::clean; |
251 | |
252 | # Will print: 'No', 'No', 'Yes' and 'No' |
253 | print +(__PACKAGE__->can('croak') ? 'Yes' : 'No'), "\n"; |
254 | print +(__PACKAGE__->can('bar') ? 'Yes' : 'No'), "\n"; |
255 | print +(__PACKAGE__->can('baz') ? 'Yes' : 'No'), "\n"; |
256 | print +(__PACKAGE__->can('quux') ? 'Yes' : 'No'), "\n"; |
257 | |
258 | 1; |
259 | |
260 | =head1 DESCRIPTION |
261 | |
262 | =head2 Keeping packages clean |
263 | |
264 | When you define a function, or import one, into a Perl package, it will |
265 | naturally also be available as a method. This does not per se cause |
266 | problems, but it can complicate subclassing and, for example, plugin |
267 | classes that are included via multiple inheritance by loading them as |
268 | base classes. |
269 | |
270 | The C<namespace::clean> pragma will remove all previously declared or |
271 | imported symbols at the end of the current package's compile cycle. |
272 | Functions called in the package itself will still be bound by their |
273 | name, but they won't show up as methods on your class or instances. |
274 | |
275 | By unimporting via C<no> you can tell C<namespace::clean> to start |
276 | collecting functions for the next C<use namespace::clean;> specification. |
277 | |
278 | You can use the C<-except> flag to tell C<namespace::clean> that you |
279 | don't want it to remove a certain function or method. A common use would |
280 | be a module exporting an C<import> method along with some functions: |
281 | |
282 | use ModuleExportingImport; |
283 | use namespace::clean -except => [qw( import )]; |
284 | |
285 | If you just want to C<-except> a single sub, you can pass it directly. |
286 | For more than one value you have to use an array reference. |
287 | |
288 | =head2 Explicitly removing functions when your scope is compiled |
289 | |
290 | It is also possible to explicitly tell C<namespace::clean> what packages |
291 | to remove when the surrounding scope has finished compiling. Here is an |
292 | example: |
293 | |
294 | package Foo; |
295 | use strict; |
296 | |
297 | # blessed NOT available |
298 | |
299 | sub my_class { |
300 | use Scalar::Util qw( blessed ); |
301 | use namespace::clean qw( blessed ); |
302 | |
303 | # blessed available |
304 | return blessed shift; |
305 | } |
306 | |
307 | # blessed NOT available |
308 | |
309 | =head2 Moose |
310 | |
311 | When using C<namespace::clean> together with L<Moose> you want to keep |
312 | the installed C<meta> method. So your classes should look like: |
313 | |
314 | package Foo; |
315 | use Moose; |
316 | use namespace::clean -except => 'meta'; |
317 | ... |
318 | |
319 | Same goes for L<Moose::Role>. |
320 | |
321 | =head2 Cleaning other packages |
322 | |
323 | You can tell C<namespace::clean> that you want to clean up another package |
324 | instead of the one importing. To do this you have to pass in the C<-cleanee> |
325 | option like this: |
326 | |
327 | package My::MooseX::namespace::clean; |
328 | use strict; |
329 | |
330 | use namespace::clean (); # no cleanup, just load |
331 | |
332 | sub import { |
333 | namespace::clean->import( |
334 | -cleanee => scalar(caller), |
335 | -except => 'meta', |
336 | ); |
337 | } |
338 | |
339 | If you don't care about C<namespace::clean>s discover-and-C<-except> logic, and |
340 | just want to remove subroutines, try L</clean_subroutines>. |
341 | |
342 | =head1 METHODS |
343 | |
344 | =head2 clean_subroutines |
345 | |
346 | This exposes the actual subroutine-removal logic. |
347 | |
348 | namespace::clean->clean_subroutines($cleanee, qw( subA subB )); |
349 | |
350 | will remove C<subA> and C<subB> from C<$cleanee>. Note that this will remove the |
351 | subroutines B<immediately> and not wait for scope end. If you want to have this |
352 | effect at a specific time (e.g. C<namespace::clean> acts on scope compile end) |
353 | it is your responsibility to make sure it runs at that time. |
354 | |
355 | =head2 import |
356 | |
357 | Makes a snapshot of the current defined functions and installs a |
358 | L<B::Hooks::EndOfScope> hook in the current scope to invoke the cleanups. |
359 | |
360 | |
361 | =head2 unimport |
362 | |
363 | This method will be called when you do a |
364 | |
365 | no namespace::clean; |
366 | |
367 | It will start a new section of code that defines functions to clean up. |
368 | |
369 | =head2 get_class_store |
370 | |
371 | This returns a reference to a hash in a passed package containing |
372 | information about function names included and excluded from removal. |
373 | |
374 | =head2 get_functions |
375 | |
376 | Takes a class as argument and returns all currently defined functions |
377 | in it as a hash reference with the function name as key and a typeglob |
378 | reference to the symbol as value. |
379 | |
6c0ece9b |
380 | =head1 IMPLEMENTATION DETAILS |
381 | |
04312494 |
382 | This module works through the effect that a |
6c0ece9b |
383 | |
384 | delete $SomePackage::{foo}; |
385 | |
386 | will remove the C<foo> symbol from C<$SomePackage> for run time lookups |
387 | (e.g., method calls) but will leave the entry alive to be called by |
472d4b1e |
388 | already resolved names in the package itself. C<namespace::clean> will |
389 | restore and therefor in effect keep all glob slots that aren't C<CODE>. |
6c0ece9b |
390 | |
391 | A test file has been added to the perl core to ensure that this behaviour |
392 | will be stable in future releases. |
393 | |
394 | Just for completeness sake, if you want to remove the symbol completely, |
395 | use C<undef> instead. |
396 | |
40aef9d6 |
397 | =head1 SEE ALSO |
398 | |
705fe1b1 |
399 | L<B::Hooks::EndOfScope> |
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400 | |
04312494 |
401 | =head1 THANKS |
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402 | |
04312494 |
403 | Many thanks to Matt S Trout for the inspiration on the whole idea. |
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404 | |
fa84e425 |
405 | =head1 AUTHORS |
406 | |
407 | =over |
408 | |
409 | =item * |
410 | |
411 | Robert 'phaylon' Sedlacek <rs@474.at> |
412 | |
413 | =item * |
414 | |
415 | Florian Ragwitz <rafl@debian.org> |
416 | |
417 | =item * |
418 | |
419 | Jesse Luehrs <doy@tozt.net> |
420 | |
421 | =item * |
422 | |
423 | Peter Rabbitson <ribasushi@cpan.org> |
424 | |
b2e54862 |
425 | =item * |
426 | |
427 | Father Chrysostomos <sprout@cpan.org> |
428 | |
fa84e425 |
429 | =back |
430 | |
431 | =head1 COPYRIGHT AND LICENSE |
432 | |
b2e54862 |
433 | This software is copyright (c) 2011 by L</AUTHORS> |
fa84e425 |
434 | |
435 | This is free software; you can redistribute it and/or modify it under the same terms as the Perl 5 programming language system itself. |