1 package namespace::clean;
9 our $STORAGE_VAR = '__NAMESPACE_CLEAN_STORAGE';
11 use B::Hooks::EndOfScope 'on_scope_end';
14 # Constant to optimise away the unused code branches
15 use constant FIXUP_NEEDED => $] < 5.015_005_1;
16 use constant FIXUP_RENAME_SUB => $] > 5.008_008_9 && $] < 5.013_005_1;
19 delete ${__PACKAGE__."::"}{FIXUP_NEEDED};
20 delete ${__PACKAGE__."::"}{FIXUP_RENAME_SUB};
23 # Debugger fixup necessary before perl 5.15.5
25 # In perl 5.8.9-5.12, it assumes that sub_fullname($sub) can
26 # always be used to find the CV again.
27 # In perl 5.8.8 and 5.14, it assumes that the name of the glob
28 # passed to entersub can be used to find the CV.
29 # since we are deleting the glob where the subroutine was originally
30 # defined, those assumptions no longer hold.
32 # So in 5.8.9-5.12 we need to move it elsewhere and point the
33 # CV's name to the new glob.
35 # In 5.8.8 and 5.14 we move it elsewhere and rename the
36 # original glob by assigning the new glob back to it.
38 my $DebuggerFixup = sub {
39 my ($f, $sub, $cleanee_stash, $deleted_stash) = @_;
41 if (FIXUP_RENAME_SUB) {
42 if (! defined $sub_utils_loaded ) {
43 $sub_utils_loaded = do {
45 # when changing version also change in Makefile.PL
47 eval { require Sub::Name; Sub::Name->VERSION($sn_ver) }
48 or die "Sub::Name $sn_ver required when running under -d or equivalent: $@";
50 # when changing version also change in Makefile.PL
52 eval { require Sub::Identify; Sub::Identify->VERSION($si_ver) }
53 or die "Sub::Identify $si_ver required when running under -d or equivalent: $@";
59 if ( Sub::Identify::sub_fullname($sub) eq ($cleanee_stash->name . "::$f") ) {
60 my $new_fq = $deleted_stash->name . "::$f";
61 Sub::Name::subname($new_fq, $sub);
62 $deleted_stash->add_symbol("&$f", $sub);
66 $deleted_stash->add_symbol("&$f", $sub);
70 my $RemoveSubs = sub {
73 my $cleanee_stash = Package::Stash->new($cleanee);
79 # ignore already removed symbols
80 next SYMBOL if $store->{exclude}{ $f };
82 my $sub = $cleanee_stash->get_symbol("&$f")
85 my $need_debugger_fixup =
90 ref(my $globref = \$cleanee_stash->namespace->{$f}) eq 'GLOB'
93 if (FIXUP_NEEDED && $need_debugger_fixup) {
94 # convince the Perl debugger to work
95 # see the comment on top of $DebuggerFixup
100 $deleted_stash ||= Package::Stash->new("namespace::clean::deleted::$cleanee"),
106 my $def = $cleanee_stash->get_symbol($name);
107 defined($def) ? [$name, $def] : ()
110 $cleanee_stash->remove_glob($f);
112 # if this perl needs no renaming trick we need to
113 # rename the original glob after the fact
114 # (see commend of $DebuggerFixup
115 if (FIXUP_NEEDED && !FIXUP_RENAME_SUB && $need_debugger_fixup) {
116 *$globref = $deleted_stash->namespace->{$f};
119 $cleanee_stash->add_symbol(@$_) for @symbols;
123 sub clean_subroutines {
124 my ($nc, $cleanee, @subs) = @_;
125 $RemoveSubs->($cleanee, {}, @subs);
129 my ($pragma, @args) = @_;
131 my (%args, $is_explicit);
136 if ($args[0] =~ /^\-/) {
137 my $key = shift @args;
138 my $value = shift @args;
139 $args{ $key } = $value;
147 my $cleanee = exists $args{ -cleanee } ? $args{ -cleanee } : scalar caller;
150 $RemoveSubs->($cleanee, {}, @args);
155 # calling class, all current functions and our storage
156 my $functions = $pragma->get_functions($cleanee);
157 my $store = $pragma->get_class_store($cleanee);
158 my $stash = Package::Stash->new($cleanee);
160 # except parameter can be array ref or single value
161 my %except = map {( $_ => 1 )} (
163 ? ( ref $args{ -except } eq 'ARRAY' ? @{ $args{ -except } } : $args{ -except } )
167 # register symbols for removal, if they have a CODE entry
168 for my $f (keys %$functions) {
169 next if $except{ $f };
170 next unless $stash->has_symbol("&$f");
171 $store->{remove}{ $f } = 1;
174 # register EOF handler on first call to import
175 unless ($store->{handler_is_installed}) {
177 $RemoveSubs->($cleanee, $store, keys %{ $store->{remove} });
179 $store->{handler_is_installed} = 1;
187 my ($pragma, %args) = @_;
189 # the calling class, the current functions and our storage
190 my $cleanee = exists $args{ -cleanee } ? $args{ -cleanee } : scalar caller;
191 my $functions = $pragma->get_functions($cleanee);
192 my $store = $pragma->get_class_store($cleanee);
194 # register all unknown previous functions as excluded
195 for my $f (keys %$functions) {
196 next if $store->{remove}{ $f }
197 or $store->{exclude}{ $f };
198 $store->{exclude}{ $f } = 1;
204 sub get_class_store {
205 my ($pragma, $class) = @_;
206 my $stash = Package::Stash->new($class);
207 my $var = "%$STORAGE_VAR";
208 $stash->add_symbol($var, {})
209 unless $stash->has_symbol($var);
210 return $stash->get_symbol($var);
214 my ($pragma, $class) = @_;
216 my $stash = Package::Stash->new($class);
218 map { $_ => $stash->get_symbol("&$_") }
219 $stash->list_all_symbols('CODE')
223 'Danger! Laws of Thermodynamics may not apply.'
229 namespace::clean - Keep imports and functions out of your namespace
237 use Carp qw(croak); # 'croak' will be removed
239 sub bar { 23 } # 'bar' will be removed
241 # remove all previously defined functions
242 use namespace::clean;
244 sub baz { bar() } # 'baz' still defined, 'bar' still bound
246 # begin to collection function names from here again
249 sub quux { baz() } # 'quux' will be removed
251 # remove all functions defined after the 'no' unimport
252 use namespace::clean;
254 # Will print: 'No', 'No', 'Yes' and 'No'
255 print +(__PACKAGE__->can('croak') ? 'Yes' : 'No'), "\n";
256 print +(__PACKAGE__->can('bar') ? 'Yes' : 'No'), "\n";
257 print +(__PACKAGE__->can('baz') ? 'Yes' : 'No'), "\n";
258 print +(__PACKAGE__->can('quux') ? 'Yes' : 'No'), "\n";
264 =head2 Keeping packages clean
266 When you define a function, or import one, into a Perl package, it will
267 naturally also be available as a method. This does not per se cause
268 problems, but it can complicate subclassing and, for example, plugin
269 classes that are included via multiple inheritance by loading them as
272 The C<namespace::clean> pragma will remove all previously declared or
273 imported symbols at the end of the current package's compile cycle.
274 Functions called in the package itself will still be bound by their
275 name, but they won't show up as methods on your class or instances.
277 By unimporting via C<no> you can tell C<namespace::clean> to start
278 collecting functions for the next C<use namespace::clean;> specification.
280 You can use the C<-except> flag to tell C<namespace::clean> that you
281 don't want it to remove a certain function or method. A common use would
282 be a module exporting an C<import> method along with some functions:
284 use ModuleExportingImport;
285 use namespace::clean -except => [qw( import )];
287 If you just want to C<-except> a single sub, you can pass it directly.
288 For more than one value you have to use an array reference.
290 =head2 Explicitly removing functions when your scope is compiled
292 It is also possible to explicitly tell C<namespace::clean> what packages
293 to remove when the surrounding scope has finished compiling. Here is an
299 # blessed NOT available
302 use Scalar::Util qw( blessed );
303 use namespace::clean qw( blessed );
306 return blessed shift;
309 # blessed NOT available
313 When using C<namespace::clean> together with L<Moose> you want to keep
314 the installed C<meta> method. So your classes should look like:
318 use namespace::clean -except => 'meta';
321 Same goes for L<Moose::Role>.
323 =head2 Cleaning other packages
325 You can tell C<namespace::clean> that you want to clean up another package
326 instead of the one importing. To do this you have to pass in the C<-cleanee>
329 package My::MooseX::namespace::clean;
332 use namespace::clean (); # no cleanup, just load
335 namespace::clean->import(
336 -cleanee => scalar(caller),
341 If you don't care about C<namespace::clean>s discover-and-C<-except> logic, and
342 just want to remove subroutines, try L</clean_subroutines>.
346 =head2 clean_subroutines
348 This exposes the actual subroutine-removal logic.
350 namespace::clean->clean_subroutines($cleanee, qw( subA subB ));
352 will remove C<subA> and C<subB> from C<$cleanee>. Note that this will remove the
353 subroutines B<immediately> and not wait for scope end. If you want to have this
354 effect at a specific time (e.g. C<namespace::clean> acts on scope compile end)
355 it is your responsibility to make sure it runs at that time.
359 Makes a snapshot of the current defined functions and installs a
360 L<B::Hooks::EndOfScope> hook in the current scope to invoke the cleanups.
365 This method will be called when you do a
369 It will start a new section of code that defines functions to clean up.
371 =head2 get_class_store
373 This returns a reference to a hash in a passed package containing
374 information about function names included and excluded from removal.
378 Takes a class as argument and returns all currently defined functions
379 in it as a hash reference with the function name as key and a typeglob
380 reference to the symbol as value.
382 =head1 IMPLEMENTATION DETAILS
384 This module works through the effect that a
386 delete $SomePackage::{foo};
388 will remove the C<foo> symbol from C<$SomePackage> for run time lookups
389 (e.g., method calls) but will leave the entry alive to be called by
390 already resolved names in the package itself. C<namespace::clean> will
391 restore and therefor in effect keep all glob slots that aren't C<CODE>.
393 A test file has been added to the perl core to ensure that this behaviour
394 will be stable in future releases.
396 Just for completeness sake, if you want to remove the symbol completely,
397 use C<undef> instead.
401 L<B::Hooks::EndOfScope>
405 Many thanks to Matt S Trout for the inspiration on the whole idea.
413 Robert 'phaylon' Sedlacek <rs@474.at>
417 Florian Ragwitz <rafl@debian.org>
421 Jesse Luehrs <doy@tozt.net>
425 Peter Rabbitson <ribasushi@cpan.org>
429 Father Chrysostomos <sprout@cpan.org>
433 =head1 COPYRIGHT AND LICENSE
435 This software is copyright (c) 2011 by L</AUTHORS>
437 This is free software; you can redistribute it and/or modify it under the same terms as the Perl 5 programming language system itself.