Added support for policy based explicit/implicit constructor

git-svn-id: svn://svn.code.sf.net/p/loki-lib/code/trunk@131 7ec92016-0320-0410-acc4-a06ded1c099a

Reference/SmartPtr.h

@@ -779,10 +779,27 @@ namespace Loki
                 SmartPtr, const SmartPtr>::Result
             CopyArg;
     
+    private:
+        struct NeverMatched;
+       
+#ifdef LOKI_SMARTPTR_CONVERSION_CONSTRUCTOR_POLICY
+        typedef typename Select< CP::allow, const StoredType&, NeverMatched>::Result ImplicitArg;
+        typedef typename Select<!CP::allow, const StoredType&, NeverMatched>::Result ExplicitArg;
+#else
+        typedef const StoredType& ImplicitArg;
+        typedef typename Select<false, const StoredType&, NeverMatched>::Result ExplicitArg;
+#endif
+
+    public:
+
         SmartPtr()
         { KP::OnDefault(GetImpl(*this)); }
         
-        SmartPtr(const StoredType& p) : SP(p)
+        explicit
+        SmartPtr(ExplicitArg p) : SP(p)
+        { KP::OnInit(GetImpl(*this)); }
+
+        SmartPtr(ImplicitArg p) : SP(p)
         { KP::OnInit(GetImpl(*this)); }
 
         SmartPtr(CopyArg& rhs)
@@ -1231,6 +1248,14 @@ namespace std
 // June 20,     2001: ported by Nick Thurn to gcc 2.95.3. Kudos, Nick!!!
 // December 09, 2001: Included <cassert>
 // February 2,  2003: fixed dependent names - credit due to Rani Sharoni
+// August   21, 2003: Added support for policy based explicit/implicit constructor.
+//  The new code will be effective if a macro named 
+//  *** LOKI_SMARTPTR_CONVERSION_CONSTRUCTOR_POLICY ***
+//  is defined (due to backward computability concerns).
+//  In case that the macro is defined and the conversion policy allow flag is off 
+//  (e.g. DisallowConversion) then the conversion from the "pointer" to the 
+//  SmartPtr must be explicit.
+
 ////////////////////////////////////////////////////////////////////////////////
 
 #endif // SMARTPTR_INC_