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