From 8d171a297e01c19c7c5357deaf79ab417fdefad0 Mon Sep 17 00:00:00 2001
From: Alessandro Ranellucci <aar@cpan.org>
Date: Thu, 11 Jul 2013 16:17:36 +0200
Subject: [PATCH] Add thread cleanup to avoid double destruction of shared XS
 data

---
 lib/Slic3r.pm            | 21 ++++++++++++++++-----
 lib/Slic3r/GUI/Plater.pm |  3 +++
 2 files changed, 19 insertions(+), 5 deletions(-)

diff --git a/lib/Slic3r.pm b/lib/Slic3r.pm
index 00d19713..a8b0a540 100644
--- a/lib/Slic3r.pm
+++ b/lib/Slic3r.pm
@@ -87,11 +87,9 @@ sub parallelize {
         $q->enqueue(@items, (map undef, 1..$Config->threads));
         
         my $thread_cb = sub {
-            # prevent destruction of shared objects
-            no warnings 'redefine';
-            *Slic3r::ExPolygon::XS::DESTROY = sub {};
-            
-            return $params{thread_cb}->($q);
+            my $result = $params{thread_cb}->($q);
+            Slic3r::thread_cleanup();
+            return $result;
         };
             
         @_ = ();
@@ -103,6 +101,19 @@ sub parallelize {
     }
 }
 
+# call this at the very end of each thread (except the main one)
+# so that it does not try to free existing objects.
+# at that stage, existing objects are only those that we 
+# inherited at the thread creation (thus shared) and those 
+# that we are returning: destruction will be handled by the
+# main thread in both cases.
+sub thread_cleanup {
+    # prevent destruction of shared objects
+    no warnings 'redefine';
+    *Slic3r::ExPolygon::XS::DESTROY = sub {};
+    *Slic3r::Point::XS::DESTROY     = sub {};
+}
+
 sub encode_path {
     my ($filename) = @_;
     return encode('locale_fs', $filename);
diff --git a/lib/Slic3r/GUI/Plater.pm b/lib/Slic3r/GUI/Plater.pm
index dee59215..ef75ddb3 100644
--- a/lib/Slic3r/GUI/Plater.pm
+++ b/lib/Slic3r/GUI/Plater.pm
@@ -570,6 +570,7 @@ sub export_gcode {
                     });
                 },
             );
+            Slic3r::thread_cleanup();
         });
         $self->statusbar->SetCancelCallback(sub {
             $self->{export_thread}->kill('KILL')->join;
@@ -744,6 +745,8 @@ sub make_thumbnail {
         } else {
             $self->on_thumbnail_made($obj_idx);
         }
+        
+        Slic3r::thread_cleanup() if $Slic3r::have_threads;
     };
     
     @_ = ();