From 661c3fc55472439803ff3b3742ad7c83228d2fb3 Mon Sep 17 00:00:00 2001
From: Takashi Tamura <tamuratak@users.noreply.github.com>
Date: Thu, 13 Apr 2017 15:43:25 +0900
Subject: [PATCH] [ruby] treat null shared_ptr in std containers properly.

---
 Lib/ruby/rubystdcommon_forward.swg |  3 ++-
 Lib/ruby/std_shared_ptr.i          | 11 +++++++++++
 2 files changed, 13 insertions(+), 1 deletion(-)

diff --git a/Lib/ruby/rubystdcommon_forward.swg b/Lib/ruby/rubystdcommon_forward.swg
index 27bcb9960..4120b38e4 100644
--- a/Lib/ruby/rubystdcommon_forward.swg
+++ b/Lib/ruby/rubystdcommon_forward.swg
@@ -5,7 +5,8 @@ namespace swig {
   template <class Type> struct traits_asval;
   struct pointer_category;
   template <class Type, class Category> struct traits_as;
-  template<class Type> struct traits_from;
+  template <class Type> struct traits_from;
+  template <class Type> struct traits_from_ptr;
   template <class Type> struct noconst_traits;
   template <class Type> swig_type_info* type_info();
   template <class Type> const char* type_name();
diff --git a/Lib/ruby/std_shared_ptr.i b/Lib/ruby/std_shared_ptr.i
index f6c0a15ac..f2b05ef36 100644
--- a/Lib/ruby/std_shared_ptr.i
+++ b/Lib/ruby/std_shared_ptr.i
@@ -113,6 +113,17 @@ namespace swig {
     }
   };
 
+  template <class Type>
+  struct traits_from_ptr<std::shared_ptr<Type> > {
+    static VALUE from(std::shared_ptr<Type> *val, int owner = 0) {
+      if (val && *val) {
+        return SWIG_NewPointerObj(val, type_info<std::shared_ptr<Type> >(), owner);
+      } else {
+        return Qnil;
+      }
+    }
+  };
+
   /*
    The descriptors in the shared_ptr typemaps remove the const qualifier for the SWIG type system.
    Remove const likewise here, otherwise SWIG_TypeQuery("std::shared_ptr<const Type>") will return NULL.