add comment to explain use of main_start

[p5sagit/Devel-GlobalDestruction.git] / lib / Devel / GlobalDestruction.pm

diff --git a/lib/Devel/GlobalDestruction.pm b/lib/Devel/GlobalDestruction.pm
index bb90dc7..25b8958 100644 (file)
--- a/lib/Devel/GlobalDestruction.pm
+++ b/lib/Devel/GlobalDestruction.pm
@@ -1,46 +1,60 @@
-#!/usr/bin/perl
-
 package Devel::GlobalDestruction;
 
 use strict;
 use warnings;
 
-use vars qw($VERSION);
-
-use XSLoader;
-
-$VERSION = '0.02';
-
-XSLoader::load(__PACKAGE__, $VERSION);
+our $VERSION = '0.09';
 
-use Sub::Exporter -setup => {
-       exports => [ qw(in_global_destruction) ],
-       groups  => { default => [ -all ] },
+use Sub::Exporter::Progressive -setup => {
+  exports => [ qw(in_global_destruction) ],
+  groups  => { default => [ -all ] },
 };
 
-__PACKAGE__
+# we run 5.14+ - everything is in core
+#
+if (defined ${^GLOBAL_PHASE}) {
+  eval 'sub in_global_destruction () { ${^GLOBAL_PHASE} eq q[DESTRUCT] }; 1'
+    or die $@;
+}
+# try to load the xs version if it was compiled
+#
+elsif (eval {
+  require XSLoader;
+  XSLoader::load(__PACKAGE__, $VERSION);
+  1;
+}) {
+  # the eval already installed everything, nothing to do
+}
+else {
+  # internally, PL_main_start is nulled immediately before entering global destruction
+  # and we can use B to detect that
+  require B;
+  eval 'sub in_global_destruction () { B::main_start()->isa(q[B::NULL]) }; 1'
+    or die $@;
+}
+
+1;  # keep require happy
 
-__END__
 
-=pod
+__END__
 
 =head1 NAME
 
-Devel::GlobalDestruction - Expose PL_dirty, the flag which marks global
+Devel::GlobalDestruction - Expose the flag which marks global
 destruction.
 
 =head1 SYNOPSIS
 
-       package Foo;
-       use Devel::GlobalDestruction;
+    package Foo;
+    use Devel::GlobalDestruction;
 
-       use namespace::clean; # to avoid having an "in_global_destruction" method
+    use namespace::clean; # to avoid having an "in_global_destruction" method
 
-       sub DESTROY {
-               return if in_global_destruction;
+    sub DESTROY {
+        return if in_global_destruction;
 
-               do_something_a_little_tricky();
-       }
+        do_something_a_little_tricky();
+    }
 
 =head1 DESCRIPTION
 
@@ -56,32 +70,37 @@ destruction is in effect.
 
 =head1 EXPORTS
 
-This module uses L<Sub::Exporter> so the exports may be renamed, aliased, etc.
+This module uses L<Sub::Exporter::Progressive> so the exports may be renamed,
+aliased, etc. if L<Sub::Exporter> is present.
 
 =over 4
 
 =item in_global_destruction
 
-Returns the current value of C<PL_dirty>.
+Returns true if the interpreter is in global destruction. In perl 5.14+, this
+returns C<${^GLOBAL_PHASE} eq 'DESTRUCT'>, and on earlier perls, it returns the
+current value of C<PL_dirty>.
 
 =back
 
-=head1 VERSION CONTROL
+=head1 AUTHORS
 
-This module is maintained using Darcs. You can get the latest version from
-L<http://nothingmuch.woobling.org/code>, and use C<darcs send> to commit
-changes.
+Yuval Kogman E<lt>nothingmuch@woobling.orgE<gt>
 
-=head1 AUTHOR
+Florian Ragwitz E<lt>rafl@debian.orgE<gt>
 
-Yuval Kogman E<lt>nothingmuch@woobling.orgE<gt>
+Jesse Luehrs E<lt>doy@tozt.netE<gt>
 
-=head1 COPYRIGHT
+Peter Rabbitson E<lt>ribasushi@cpan.orgE<gt>
 
-       Copyright (c) 2008 Yuval Kogman. All rights reserved
-       This program is free software; you can redistribute
-       it and/or modify it under the same terms as Perl itself.
+Arthur Axel 'fREW' Schmidt E<lt>frioux@gmail.comE<gt>
 
-=cut
+Elizabeth Mattijsen E<lt>liz@dijkmat.nlE<gt>
 
+=head1 COPYRIGHT
+
+    Copyright (c) 2008 Yuval Kogman. All rights reserved
+    This program is free software; you can redistribute
+    it and/or modify it under the same terms as Perl itself.
 
+=cut