package namespace::clean;
+# ABSTRACT: Keep imports and functions out of your namespace
-=head1 NAME
+use warnings;
+use strict;
-namespace::clean - Keep imports and functions out of your namespace
+use vars qw( $STORAGE_VAR );
+use Package::Stash;
-=cut
+our $VERSION = '0.21';
-use warnings;
-use strict;
+$STORAGE_VAR = '__NAMESPACE_CLEAN_STORAGE';
-use vars qw( $VERSION $STORAGE_VAR );
-use Symbol qw( qualify_to_ref );
-use Filter::EOF;
+BEGIN {
-=head1 VERSION
+ use warnings;
+ use strict;
-0.03
+ # when changing also change in Makefile.PL
+ my $b_h_eos_req = '0.07';
-=cut
+ if (! $ENV{NAMESPACE_CLEAN_USE_PP} and eval {
+ require B::Hooks::EndOfScope;
+ B::Hooks::EndOfScope->VERSION($b_h_eos_req);
+ 1
+ } ) {
+ B::Hooks::EndOfScope->import('on_scope_end');
+ }
+ else {
+ eval <<'PP' or die $@;
-$VERSION = 0.03;
-$STORAGE_VAR = '__NAMESPACE_CLEAN_STORAGE';
+ use Tie::Hash ();
+
+ {
+ package namespace::clean::_TieHintHash;
+
+ use warnings;
+ use strict;
+
+ use base 'Tie::ExtraHash';
+ }
+
+ {
+ package namespace::clean::_ScopeGuard;
+
+ use warnings;
+ use strict;
+
+ sub arm { bless [ $_[1] ] }
+
+ sub DESTROY { $_[0]->[0]->() }
+ }
+
+
+ sub on_scope_end (&) {
+ $^H |= 0x020000;
+
+ if( my $stack = tied( %^H ) ) {
+ if ( (my $c = ref $stack) ne 'namespace::clean::_TieHintHash') {
+ die <<EOE;
+========================================================================
+ !!! F A T A L E R R O R !!!
+
+ foreign tie() of %^H detected
+========================================================================
+
+namespace::clean is currently operating in pure-perl fallback mode, because
+your system is lacking the necessary dependency B::Hooks::EndOfScope $b_h_eos_req.
+In this mode namespace::clean expects to be able to tie() the hinthash %^H,
+however it is apparently already tied by means unknown to the tie-class
+$c
+
+Since this is a no-win situation execution will abort here and now. Please
+try to find out which other module is relying on hinthash tie() ability,
+and file a bug for both the perpetrator and namespace::clean, so that the
+authors can figure out an acceptable way of moving forward.
+
+EOE
+ }
+ push @$stack, namespace::clean::_ScopeGuard->arm(shift);
+ }
+ else {
+ my %old_contents = %^H;
+ %^H = ();
+ tie( %^H, 'namespace::clean::_TieHintHash', namespace::clean::_ScopeGuard->arm(shift) );
+ $^H{$_} = $old_contents{$_} for keys %old_contents;
+ }
+ }
+
+ 1;
+
+PP
+
+ }
+}
+
+=head1 NAME
+
+namespace::clean - Keep imports and functions out of your namespace
=head1 SYNOPSIS
=head1 DESCRIPTION
+=head2 Keeping packages clean
+
When you define a function, or import one, into a Perl package, it will
naturally also be available as a method. This does not per se cause
problems, but it can complicate subclassing and, for example, plugin
-classes that are included via multiple inheritance by loading them as
+classes that are included via multiple inheritance by loading them as
base classes.
The C<namespace::clean> pragma will remove all previously declared or
By unimporting via C<no> you can tell C<namespace::clean> to start
collecting functions for the next C<use namespace::clean;> specification.
+You can use the C<-except> flag to tell C<namespace::clean> that you
+don't want it to remove a certain function or method. A common use would
+be a module exporting an C<import> method along with some functions:
+
+ use ModuleExportingImport;
+ use namespace::clean -except => [qw( import )];
+
+If you just want to C<-except> a single sub, you can pass it directly.
+For more than one value you have to use an array reference.
+
+=head2 Explicitly removing functions when your scope is compiled
+
+It is also possible to explicitly tell C<namespace::clean> what packages
+to remove when the surrounding scope has finished compiling. Here is an
+example:
+
+ package Foo;
+ use strict;
+
+ # blessed NOT available
+
+ sub my_class {
+ use Scalar::Util qw( blessed );
+ use namespace::clean qw( blessed );
+
+ # blessed available
+ return blessed shift;
+ }
+
+ # blessed NOT available
+
+=head2 Moose
+
+When using C<namespace::clean> together with L<Moose> you want to keep
+the installed C<meta> method. So your classes should look like:
+
+ package Foo;
+ use Moose;
+ use namespace::clean -except => 'meta';
+ ...
+
+Same goes for L<Moose::Role>.
+
+=head2 Cleaning other packages
+
+You can tell C<namespace::clean> that you want to clean up another package
+instead of the one importing. To do this you have to pass in the C<-cleanee>
+option like this:
+
+ package My::MooseX::namespace::clean;
+ use strict;
+
+ use namespace::clean (); # no cleanup, just load
+
+ sub import {
+ namespace::clean->import(
+ -cleanee => scalar(caller),
+ -except => 'meta',
+ );
+ }
+
+If you don't care about C<namespace::clean>s discover-and-C<-except> logic, and
+just want to remove subroutines, try L</clean_subroutines>.
+
=head1 METHODS
-You shouldn't need to call any of these. Just C<use> the package at the
-appropriate place.
+=head2 clean_subroutines
+
+This exposes the actual subroutine-removal logic.
+
+ namespace::clean->clean_subroutines($cleanee, qw( subA subB ));
+
+will remove C<subA> and C<subB> from C<$cleanee>. Note that this will remove the
+subroutines B<immediately> and not wait for scope end. If you want to have this
+effect at a specific time (e.g. C<namespace::clean> acts on scope compile end)
+it is your responsibility to make sure it runs at that time.
=cut
+# Constant to optimise away the unused code branches
+use constant RENAME_SUB => $] > 5.008_008_9 && $] < 5.013_006_1;
+{ no strict; delete ${__PACKAGE__."::"}{RENAME_SUB} }
+
+# In perl 5.8.9-5.12, it assumes that sub_fullname($sub) can
+# always be used to find the CV again.
+# In perl 5.8.8 and 5.14, it assumes that the name of the glob
+# passed to entersub can be used to find the CV.
+# since we are deleting the glob where the subroutine was originally
+# defined, those assumptions no longer hold.
+#
+# So in 5.8.9-5.12 we need to move it elsewhere and point the
+# CV's name to the new glob.
+#
+# In 5.8.8 and 5.14 we move it elsewhere and rename the
+# original glob by assigning the new glob back to it.
+my $sub_utils_loaded;
+my $DebuggerFixup = sub {
+ my ($f, $sub, $cleanee_stash, $deleted_stash) = @_;
+
+ if (RENAME_SUB) {
+ if (! defined $sub_utils_loaded ) {
+ $sub_utils_loaded = do {
+
+ # when changing version also change in Makefile.PL
+ my $sn_ver = 0.04;
+ eval { require Sub::Name; Sub::Name->VERSION($sn_ver) }
+ or die "Sub::Name $sn_ver required when running under -d or equivalent: $@";
+
+ # when changing version also change in Makefile.PL
+ my $si_ver = 0.04;
+ eval { require Sub::Identify; Sub::Identify->VERSION($si_ver) }
+ or die "Sub::Identify $si_ver required when running under -d or equivalent: $@";
+
+ 1;
+ } ? 1 : 0;
+ }
+
+ if ( Sub::Identify::sub_fullname($sub) eq ($cleanee_stash->name . "::$f") ) {
+ my $new_fq = $deleted_stash->name . "::$f";
+ Sub::Name::subname($new_fq, $sub);
+ $deleted_stash->add_symbol("&$f", $sub);
+ }
+ }
+ else {
+ $deleted_stash->add_symbol("&$f", $sub);
+ }
+};
+
+my $RemoveSubs = sub {
+ my $cleanee = shift;
+ my $store = shift;
+ my $cleanee_stash = Package::Stash->new($cleanee);
+ my $deleted_stash;
+
+ SYMBOL:
+ for my $f (@_) {
+
+ # ignore already removed symbols
+ next SYMBOL if $store->{exclude}{ $f };
+
+ my $sub = $cleanee_stash->get_symbol("&$f")
+ or next SYMBOL;
+
+ my $need_debugger_fixup =
+ $^P
+ &&
+ ref(my $globref = \$cleanee_stash->namespace->{$f}) eq 'GLOB'
+ ;
+
+ if ($need_debugger_fixup) {
+ # convince the Perl debugger to work
+ # see the comment on top of $DebuggerFixup
+ $DebuggerFixup->(
+ $f,
+ $sub,
+ $cleanee_stash,
+ $deleted_stash ||= Package::Stash->new("namespace::clean::deleted::$cleanee"),
+ );
+ }
+
+ my @symbols = map {
+ my $name = $_ . $f;
+ my $def = $cleanee_stash->get_symbol($name);
+ defined($def) ? [$name, $def] : ()
+ } '$', '@', '%', '';
+
+ $cleanee_stash->remove_glob($f);
+
+ # if this perl needs no renaming trick we need to
+ # rename the original glob after the fact
+ # (see commend of $DebuggerFixup
+ if (!RENAME_SUB && $need_debugger_fixup) {
+ *$globref = $deleted_stash->namespace->{$f};
+ }
+
+ $cleanee_stash->add_symbol(@$_) for @symbols;
+ }
+};
+
+sub clean_subroutines {
+ my ($nc, $cleanee, @subs) = @_;
+ $RemoveSubs->($cleanee, {}, @subs);
+}
+
=head2 import
-Makes a snapshot of the current defined functions and registers a
-L<Filter::EOF> cleanup routine to remove those symbols at the end
-of the compile-time.
+Makes a snapshot of the current defined functions and installs a
+L<B::Hooks::EndOfScope> hook in the current scope to invoke the cleanups.
=cut
sub import {
- my ($pragma) = @_;
-
- # calling class, all current functions and our storage
- my $cleanee = caller;
- my $functions = $pragma->get_functions($cleanee);
- my $store = $pragma->get_class_store($cleanee);
-
- # register symbols for removal, if they have a CODE entry
- for my $f (keys %$functions) {
- next unless $functions->{ $f }
- and *{ $functions->{ $f } }{CODE};
- $store->{remove}{ $f } = 1;
+ my ($pragma, @args) = @_;
+
+ my (%args, $is_explicit);
+
+ ARG:
+ while (@args) {
+
+ if ($args[0] =~ /^\-/) {
+ my $key = shift @args;
+ my $value = shift @args;
+ $args{ $key } = $value;
+ }
+ else {
+ $is_explicit++;
+ last ARG;
+ }
}
- # register EOF handler on first call to import
- unless ($store->{handler_is_installed}) {
- Filter::EOF->on_eof_call(sub {
- for my $f (keys %{ $store->{remove} }) {
- next if $store->{exclude}{ $f };
- no strict 'refs';
- delete ${ "${cleanee}::" }{ $f };
- }
- });
- $store->{handler_is_installed} = 1;
+ my $cleanee = exists $args{ -cleanee } ? $args{ -cleanee } : scalar caller;
+ if ($is_explicit) {
+ on_scope_end {
+ $RemoveSubs->($cleanee, {}, @args);
+ };
+ }
+ else {
+
+ # calling class, all current functions and our storage
+ my $functions = $pragma->get_functions($cleanee);
+ my $store = $pragma->get_class_store($cleanee);
+ my $stash = Package::Stash->new($cleanee);
+
+ # except parameter can be array ref or single value
+ my %except = map {( $_ => 1 )} (
+ $args{ -except }
+ ? ( ref $args{ -except } eq 'ARRAY' ? @{ $args{ -except } } : $args{ -except } )
+ : ()
+ );
+
+ # register symbols for removal, if they have a CODE entry
+ for my $f (keys %$functions) {
+ next if $except{ $f };
+ next unless $stash->has_symbol("&$f");
+ $store->{remove}{ $f } = 1;
+ }
+
+ # register EOF handler on first call to import
+ unless ($store->{handler_is_installed}) {
+ on_scope_end {
+ $RemoveSubs->($cleanee, $store, keys %{ $store->{remove} });
+ };
+ $store->{handler_is_installed} = 1;
+ }
+
+ return 1;
}
-
- return 1;
}
=head2 unimport
=cut
sub unimport {
- my ($pragma) = @_;
+ my ($pragma, %args) = @_;
# the calling class, the current functions and our storage
- my $cleanee = caller;
+ my $cleanee = exists $args{ -cleanee } ? $args{ -cleanee } : scalar caller;
my $functions = $pragma->get_functions($cleanee);
my $store = $pragma->get_class_store($cleanee);
=head2 get_class_store
-This returns a reference to a hash in a passed package containing
+This returns a reference to a hash in a passed package containing
information about function names included and excluded from removal.
=cut
sub get_class_store {
my ($pragma, $class) = @_;
- no strict 'refs';
- return \%{ "${class}::${STORAGE_VAR}" };
+ my $stash = Package::Stash->new($class);
+ my $var = "%$STORAGE_VAR";
+ $stash->add_symbol($var, {})
+ unless $stash->has_symbol($var);
+ return $stash->get_symbol($var);
}
=head2 get_functions
sub get_functions {
my ($pragma, $class) = @_;
+ my $stash = Package::Stash->new($class);
return {
- map { @$_ } # key => value
- grep { *{ $_->[1] }{CODE} } # only functions
- map { [$_, qualify_to_ref( $_, $class )] } # get globref
- grep { $_ !~ /::$/ } # no packages
- do { no strict 'refs'; keys %{ "${class}::" } } # symbol entries
+ map { $_ => $stash->get_symbol("&$_") }
+ $stash->list_all_symbols('CODE')
};
}
=head1 IMPLEMENTATION DETAILS
-This module works through the effect that a
+This module works through the effect that a
delete $SomePackage::{foo};
will remove the C<foo> symbol from C<$SomePackage> for run time lookups
(e.g., method calls) but will leave the entry alive to be called by
-already resolved names in the package itself.
+already resolved names in the package itself. C<namespace::clean> will
+restore and therefor in effect keep all glob slots that aren't C<CODE>.
A test file has been added to the perl core to ensure that this behaviour
will be stable in future releases.
Just for completeness sake, if you want to remove the symbol completely,
use C<undef> instead.
+=head1 CAVEATS
+
+This module is fully functional in a pure-perl environment, where
+L<B::Hooks::EndOfScope> (with the XS dependency L<Variable::Magic>), may
+not be available. However in this case this module falls back to a
+L<tie()|perlfunc/tie> of L<%^H|perlvar/%^H> which may or may not interfere
+with some crack you may be doing independently of namespace::clean.
+
+If you want to ensure that your codebase is protected from this unlikely
+clash, you need to explicitly depend on L<B::Hooks::EndOfScope>.
+
=head1 SEE ALSO
-L<Filter::EOF>
+L<B::Hooks::EndOfScope>
+
+=head1 THANKS
+
+Many thanks to Matt S Trout for the inspiration on the whole idea.
+
+=head1 AUTHORS
+
+=over
+
+=item *
+
+Robert 'phaylon' Sedlacek <rs@474.at>
+
+=item *
+
+Florian Ragwitz <rafl@debian.org>
+
+=item *
+
+Jesse Luehrs <doy@tozt.net>
+
+=item *
+
+Peter Rabbitson <ribasushi@cpan.org>
-=head1 AUTHOR AND COPYRIGHT
+=back
-Robert 'phaylon' Sedlacek C<E<lt>rs@474.atE<gt>>, with many thanks to
-Matt S Trout for the inspiration on the whole idea.
+=head1 COPYRIGHT AND LICENSE
-=head1 LICENSE
+This software is copyright (c) 2011 by Robert 'phaylon' Sedlacek.
-This program is free software; you can redistribute it and/or modify
-it under the same terms as perl itself.
+This is free software; you can redistribute it and/or modify it under the same terms as the Perl 5 programming language system itself.
=cut
-1;
+no warnings;
+'Danger! Laws of Thermodynamics may not apply.'