X-Git-Url: http://git.shadowcat.co.uk/gitweb/gitweb.cgi?a=blobdiff_plain;f=lib%2Fnamespace%2Fclean.pm;h=7db08755d28bc0a9177709ef07cdc25f903436e7;hb=d87b743521ce656edc828bd707764b6a163b3e33;hp=f02becefadf5de492c531b4b7863abe8f5fad44b;hpb=017bd598b6a69299db79e5c59b35f10d047c2d81;p=p5sagit%2Fnamespace-clean.git

diff --git a/lib/namespace/clean.pm b/lib/namespace/clean.pm
index f02bece..7db0875 100644
--- a/lib/namespace/clean.pm
+++ b/lib/namespace/clean.pm
@@ -5,11 +5,99 @@ use warnings;
 use strict;
 
 use vars qw( $STORAGE_VAR );
-use Package::Stash 0.22;
-use B::Hooks::EndOfScope 0.07;
+use Package::Stash;
+
+our $VERSION = '0.21_01';
 
 $STORAGE_VAR = '__NAMESPACE_CLEAN_STORAGE';
 
+BEGIN {
+
+  use warnings;
+  use strict;
+
+  # when changing also change in Makefile.PL
+  my $b_h_eos_req = '0.07';
+
+  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 $@;
+
+  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
 
   package Foo;
@@ -69,9 +157,9 @@ be a module exporting an C<import> method along with some functions:
 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 Explicitely removing functions when your scope is compiled
+=head2 Explicitly removing functions when your scope is compiled
 
-It is also possible to explicitely tell C<namespace::clean> what packages
+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:
 
@@ -123,7 +211,9 @@ option like this:
 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>.
 
-=method clean_subroutines
+=head1 METHODS
+
+=head2 clean_subroutines
 
 This exposes the actual subroutine-removal logic.
 
@@ -136,27 +226,51 @@ 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 $DebuggerRename = sub {
+my $DebuggerFixup = sub {
   my ($f, $sub, $cleanee_stash, $deleted_stash) = @_;
 
-  if (! defined $sub_utils_loaded ) {
-    $sub_utils_loaded = do {
-      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: $@";
+  if (RENAME_SUB) {
+    if (! defined $sub_utils_loaded ) {
+      $sub_utils_loaded = do {
 
-      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: $@";
+        # 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: $@";
 
-      1;
-    } ? 1 : 0;
-  }
+        # 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: $@";
 
-  if ( Sub::Identify::sub_fullname($sub) eq ($cleanee_stash->name . "::$f") ) {
-    my $new_fq = $deleted_stash->name . "::$f";
-    Sub::Name::subname($new_fq, $sub);
+        1;
+      } ? 1 : 0;
+    }
+
+    if ( Sub::Identify::sub_fullname($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);
   }
 };
@@ -176,18 +290,21 @@ my $RemoveSubs = sub {
         my $sub = $cleanee_stash->get_symbol("&$f")
           or next SYMBOL;
 
-        if ($^P and ref(\$cleanee_stash->namespace->{$f}) eq 'GLOB') {
-            # convince the Perl debugger to work
-            # it assumes that sub_fullname($sub) can always be used to find the CV again
-            # since we are deleting the glob where the subroutine was originally
-            # defined, that assumption no longer holds, so we need to move it
-            # elsewhere and point the CV's name to the new glob.
-            $DebuggerRename->(
-              $f,
-              $sub,
-              $cleanee_stash,
-              $deleted_stash ||= Package::Stash->new("namespace::clean::deleted::$cleanee"),
-            );
+        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 {
@@ -198,6 +315,13 @@ my $RemoveSubs = sub {
 
         $cleanee_stash->remove_glob($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;
     }
 };
@@ -207,7 +331,7 @@ sub clean_subroutines {
     $RemoveSubs->($cleanee, {}, @subs);
 }
 
-=method import
+=head2 import
 
 Makes a snapshot of the current defined functions and installs a
 L<B::Hooks::EndOfScope> hook in the current scope to invoke the cleanups.
@@ -272,7 +396,7 @@ sub import {
     }
 }
 
-=method unimport
+=head2 unimport
 
 This method will be called when you do a
 
@@ -300,7 +424,7 @@ sub unimport {
     return 1;
 }
 
-=method get_class_store
+=head2 get_class_store
 
 This returns a reference to a hash in a passed package containing
 information about function names included and excluded from removal.
@@ -316,7 +440,7 @@ sub get_class_store {
     return $stash->get_symbol($var);
 }
 
-=method get_functions
+=head2 get_functions
 
 Takes a class as argument and returns all currently defined functions
 in it as a hash reference with the function name as key and a typeglob
@@ -351,6 +475,17 @@ 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<B::Hooks::EndOfScope>
@@ -359,6 +494,34 @@ L<B::Hooks::EndOfScope>
 
 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>
+
+=back
+
+=head1 COPYRIGHT AND LICENSE
+
+This software is copyright (c) 2011 by Robert 'phaylon' Sedlacek.
+
+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
 
 no warnings;