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 cf94048..25b8958 100644 (file)
--- a/lib/Devel/GlobalDestruction.pm
+++ b/lib/Devel/GlobalDestruction.pm
@@ -3,65 +3,34 @@ package Devel::GlobalDestruction;
 use strict;
 use warnings;
 
-our $VERSION = '0.04';
+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 ] },
 };
 
+# we run 5.14+ - everything is in core
+#
 if (defined ${^GLOBAL_PHASE}) {
-    eval 'sub in_global_destruction () { ${^GLOBAL_PHASE} eq q[DESTRUCT] }';
+  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;
+  require XSLoader;
+  XSLoader::load(__PACKAGE__, $VERSION);
+  1;
 }) {
-    # the eval already installed everything, nothing to do
+  # the eval already installed everything, nothing to do
 }
 else {
-  eval <<'PP_IGD' or die $@;
-
-my ($in_global_destruction, $before_is_installed);
-
-sub in_global_destruction { $in_global_destruction }
-
-END {
-  # SpeedyCGI runs END blocks every cycle but somehow keeps object instances
-  # hence lying about it seems reasonable...ish
-  $in_global_destruction = 1 unless $CGI::SpeedyCGI::i_am_speedy;
-}
-
-# threads do not execute the global ENDs (it would be stupid). However
-# one can register a new END via simple string eval within a thread, and
-# achieve the same result. A logical place to do this would be CLONE, which
-# is claimed to run in the context of the new thread. However this does
-# not really seem to be the case - any END evaled in a CLONE is ignored :(
-# Hence blatantly hooking threads::create
-
-if ($INC{'threads.pm'}) {
-  my $orig_create = threads->can('create');
-  no warnings 'redefine';
-  *threads::create = sub {
-    { local $@; eval 'END { $in_global_destruction = 1 }' };
-    goto $orig_create;
-  };
-  $before_is_installed = 1;
-}
-
-# just in case threads got loaded after us (silly)
-sub CLONE {
-  unless ($before_is_installed) {
-    require Carp;
-    Carp::croak("You must load the 'threads' module before @{[ __PACKAGE__ ]}");
-  }
-}
-
-1;  # keep eval happy
-
-PP_IGD
-
+  # 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
@@ -101,7 +70,8 @@ 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
 
@@ -123,6 +93,10 @@ Jesse Luehrs E<lt>doy@tozt.netE<gt>
 
 Peter Rabbitson E<lt>ribasushi@cpan.orgE<gt>
 
+Arthur Axel 'fREW' Schmidt E<lt>frioux@gmail.comE<gt>
+
+Elizabeth Mattijsen E<lt>liz@dijkmat.nlE<gt>
+
 =head1 COPYRIGHT
 
     Copyright (c) 2008 Yuval Kogman. All rights reserved