gras: revisit container storage after yesterdays learning

The mechanisms of connect are now resonsible for grabbing the container ref.
When the object is a shared ptr, the element contructor overload sets weakself.
When the object is in python, the python reference is held,
even if its shared ptr underneath that.

* removed the need for shared_from_this
* removed the ref stuff in python Block

1 files changed, 26 insertions, 1 deletions

diff --git a/include/gras/detail/element.hpp b/include/gras/detail/element.hpp
index 2b97c8f..f8a8904 100644
--- a/include/gras/detail/element.hpp
+++ b/include/gras/detail/element.hpp
@@ -3,12 +3,37 @@
 #ifndef INCLUDED_GRAS_DETAIL_ELEMENT_HPP
 #define INCLUDED_GRAS_DETAIL_ELEMENT_HPP
 
+#include <boost/weak_ptr.hpp>
+
 namespace gras
 {
+
+    //! Weak element overload for the case of shared_ptr container
+    struct WeakElementSharedPtr : WeakElement
+    {
+        WeakElementSharedPtr(boost::weak_ptr<const void> weak_self)
+        {
+            _weak_self = weak_self;
+        }
+        boost::shared_ptr<const void> lock(void)
+        {
+            return _weak_self.lock();
+        }
+        boost::weak_ptr<const void> _weak_self;
+    };
+
     template <typename T>
     inline Element::Element(const boost::shared_ptr<T> &elem)
     {
-        *this = elem->shared_to_element();
+        //the container is a shared pointer, so save the reference,
+        //unless the reference was already set to something
+        if (not elem->weak_self)
+        {
+            elem->weak_self.reset(new WeakElementSharedPtr(elem));
+        }
+
+        //initialize this new Element from the argument passed
+        *this = *elem;
     }
 
 } //namespace gras