Added weak_from_raw(), for use in conjunction with

enable_shared_from_raw base class.



[SVN r57423]

include/boost/smart_ptr/enable_shared_from_raw.hpp

@@ -21,6 +21,7 @@
 namespace boost
 {
 template<typename T> boost::shared_ptr<T> shared_from_raw(T *);
+template<typename T> boost::weak_ptr<T> weak_from_raw(T *);
 
 namespace detail
 {
@@ -72,6 +73,7 @@ public:
 private:
     template<class Y> friend class shared_ptr;
     template<typename T> friend boost::shared_ptr<T> shared_from_raw(T *);
+    template<typename T> friend boost::weak_ptr<T> weak_from_raw(T *);
     template< class X, class Y > friend inline void detail::sp_enable_shared_from_this( boost::shared_ptr<X> * ppx, Y const * py, boost::enable_shared_from_raw const * pe );
 #endif
 
@@ -114,9 +116,19 @@ private:
 template<typename T>
 boost::shared_ptr<T> shared_from_raw(T *p)
 {
+    BOOST_ASSERT(p != 0);
     return boost::shared_ptr<T>(p->enable_shared_from_raw::shared_from_this(), p);
 }
 
+template<typename T>
+boost::weak_ptr<T> weak_from_raw(T *p)
+{
+    BOOST_ASSERT(p != 0);
+    boost::weak_ptr<T> result;
+    result._internal_aliasing_assign(p->enable_shared_from_raw::weak_this_, p);
+    return result;
+}
+
 namespace detail
 {
     template< class X, class Y > inline void sp_enable_shared_from_this( boost::shared_ptr<X> * ppx, Y const * py, boost::enable_shared_from_raw const * pe )

include/boost/smart_ptr/weak_ptr.hpp

@@ -183,10 +183,11 @@ public:
         pn.swap(other.pn);
     }
 
-    void _internal_assign(T * px2, boost::detail::shared_count const & pn2)
+    template<typename Y>
+    void _internal_aliasing_assign(weak_ptr<Y> const & r, T * px2)
     {
         px = px2;
-        pn = pn2;
+        pn = r.pn;
     }
 
     template<class Y> bool _internal_less(weak_ptr<Y> const & rhs) const
@@ -225,6 +226,6 @@ template<class T> void swap(weak_ptr<T> & a, weak_ptr<T> & b)
 
 #ifdef BOOST_MSVC
 # pragma warning(pop)
-#endif    
+#endif
 
 #endif  // #ifndef BOOST_SMART_PTR_WEAK_PTR_HPP_INCLUDED

test/Jamfile.v2

@@ -59,6 +59,7 @@ import testing ;
           [ run sp_recursive_assign_rv_test.cpp ]
           [ run sp_recursive_assign2_rv_test.cpp ]
           [ run esft_constructor_test.cpp ]
+          [ run enable_shared_from_raw_test.cpp ]
           [ compile-fail auto_ptr_lv_fail.cpp ]
           [ run atomic_count_test2.cpp ]
         ;

test/enable_shared_from_raw_test.cpp

@@ -0,0 +1,39 @@
+#include <boost/config.hpp>
+
+//
+//  weak_from_raw_test.cpp
+//
+//  Copyright (c) 2009 Frank Mori Hess
+//
+// Distributed under the Boost Software License, Version 1.0. (See
+// accompanying file LICENSE_1_0.txt or copy at
+// http://www.boost.org/LICENSE_1_0.txt)
+//
+
+
+#include <boost/smart_ptr/enable_shared_from_raw.hpp>
+
+#include <boost/detail/lightweight_test.hpp>
+
+
+struct X: public boost::enable_shared_from_raw
+{};
+
+void basic_weak_from_raw_test()
+{
+    X *p(new X);
+    boost::weak_ptr<X> weak = boost::weak_from_raw(p);
+    BOOST_TEST(weak.expired());
+    boost::shared_ptr<X> shared(p);
+    weak = boost::weak_from_raw(p);
+    BOOST_TEST(weak.expired() == false);
+    boost::shared_ptr<X> shared2(weak);
+    BOOST_TEST((shared < shared2 || shared2 < shared) == false);
+    BOOST_TEST(shared.get() == p);
+}
+
+int main()
+{
+    basic_weak_from_raw_test();
+    return boost::report_errors();
+}