Merge [51909], [51912], [52937], [53672] to release.

[SVN r55479]

include/boost/smart_ptr/weak_ptr.hpp

@@ -70,11 +70,43 @@ public:
     weak_ptr( weak_ptr<Y> const & r )
 
 #endif
-    : pn(r.pn) // never throws
+    : px(r.lock().get()), pn(r.pn) // never throws
     {
-        px = r.lock().get();
     }
 
+#if defined( BOOST_HAS_RVALUE_REFS )
+
+    template<class Y>
+#if !defined( BOOST_SP_NO_SP_CONVERTIBLE )
+
+    weak_ptr( weak_ptr<Y> && r, typename detail::sp_enable_if_convertible<Y,T>::type = detail::sp_empty() )
+
+#else
+
+    weak_ptr( weak_ptr<Y> && r )
+
+#endif
+    : px(r.lock().get()), pn(std::move(r.pn)) // never throws
+    {
+        r.px = 0;
+    }
+
+    // for better efficiency in the T == Y case
+    weak_ptr( weak_ptr && r ): px( r.px ), pn(std::move(r.pn)) // never throws
+    {
+        r.px = 0;
+    }
+
+    // for better efficiency in the T == Y case
+    weak_ptr & operator=( weak_ptr && r ) // never throws
+    {
+        this_type( std::move( r ) ).swap( *this );
+        return *this;
+    }
+
+
+#endif
+
     template<class Y>
 #if !defined( BOOST_SP_NO_SP_CONVERTIBLE )
 
@@ -99,6 +131,17 @@ public:
         return *this;
     }
 
+#if defined( BOOST_HAS_RVALUE_REFS )
+
+    template<class Y>
+    weak_ptr & operator=(weak_ptr<Y> && r)
+    {
+        this_type( std::move( r ) ).swap( *this );
+        return *this;
+    }
+
+#endif
+
     template<class Y>
     weak_ptr & operator=(shared_ptr<Y> const & r) // never throws
     {
@@ -124,6 +167,11 @@ public:
         return pn.use_count() == 0;
     }
 
+    bool _empty() const // extension, not in std::weak_ptr
+    {
+        return pn.empty();
+    }
+
     void reset() // never throws in 1.30+
     {
         this_type().swap(*this);