[PATCH] Proof of concept - conversion operator for uno::Reference

[Thorsten Behrens (via Code Review)]

Hi,

I have submitted a patch for review:

    https://gerrit.libreoffice.org/3698

To pull it, you can do:

    git pull ssh://gerrit.libreoffice.org:29418/core refs/changes/98/3698/1

Proof of concept - conversion operator for uno::Reference

Change-Id: I589b57c0a54524460fc8518a456dc09797c3567a
---
M include/com/sun/star/uno/Reference.h
M include/com/sun/star/uno/Reference.hxx
2 files changed, 56 insertions(+), 5 deletions(-)



diff --git a/include/com/sun/star/uno/Reference.h b/include/com/sun/star/uno/Reference.h
index 94551a0..2b776b8 100644
--- a/include/com/sun/star/uno/Reference.h
+++ b/include/com/sun/star/uno/Reference.h
@@ -19,6 +19,8 @@
 #ifndef _COM_SUN_STAR_UNO_REFERENCE_H_
 #define _COM_SUN_STAR_UNO_REFERENCE_H_
 
+#include <boost/config.hpp> // for BOOST_NO_MEMBER_TEMPLATE_FRIENDS macro
+
 #include <rtl/alloc.h>
 
 
@@ -54,10 +56,6 @@
 class BaseReference
 {
 protected:
-    /** the interface pointer
-    */
-    XInterface * _pInterface;
-
     /** Queries given interface for type rType.
 
         @param pInterface interface pointer
@@ -77,6 +75,19 @@
     inline static XInterface * SAL_CALL iquery_throw( XInterface * pInterface, const Type & rType )
         SAL_THROW( (RuntimeException) );
 #endif
+
+// if member template friends don't work, make protected _pInterface
+// public, to allow template copy constructor from Reference to access
+// them.
+#ifndef BOOST_NO_MEMBER_TEMPLATE_FRIENDS
+    template<typename T> friend class Reference;
+#else
+public:
+#endif
+
+    /** the interface pointer
+    */
+    XInterface * _pInterface;
 
 public:
     /** Gets interface pointer. This call does not acquire the interface.
@@ -332,6 +343,15 @@
     inline Reference( interface_type * pInterface, UnoReference_SetThrow dummy ) SAL_THROW( (RuntimeException) );
 #endif
 
+    /* Constructor: copy-construct from derived interface
+
+       @param rRef
+       Interface reference that must be convertible to interface_type
+       (typically, this implies that interface_type is a basetype of
+       the passed type)
+     */
+    template< class Ifc > inline Reference( const Reference<Ifc>& rRef );
+
     /** Cast operator to Reference< XInterface >: Reference objects are binary compatible and
         any interface must be derived from com.sun.star.uno.XInterface.
         This a useful direct cast possibility.
@@ -485,6 +505,18 @@
     */
     inline Reference< interface_type > & SAL_CALL operator = ( const Reference< interface_type > & rRef ) SAL_THROW(());
 
+    /** Assignment operator for derived interfaces: Acquires given
+        interface reference and sets reference.  An interface already
+        set will be released.
+
+        @param rRef
+        Interface reference that must be convertible to interface_type
+        (typically, this implies that interface_type is a basetype of
+        the passed type)
+     */
+    template< class Ifc >
+    inline Reference< interface_type > & SAL_CALL operator = ( const Reference<Ifc>& rRef );
+
     /** Queries given interface reference for type interface_type.
 
         @param rRef interface reference
diff --git a/include/com/sun/star/uno/Reference.hxx b/include/com/sun/star/uno/Reference.hxx
index aa39810..9b84809 100644
--- a/include/com/sun/star/uno/Reference.hxx
+++ b/include/com/sun/star/uno/Reference.hxx
@@ -193,7 +193,16 @@
     _pInterface = castToXInterface( iset_throw( pInterface ) );
 }
 #endif
-
+//__________________________________________________________________________________________________
+template< class interface_type >
+template< class Ifc >
+inline Reference< interface_type >::Reference( const Reference<Ifc>& rRef )
+{
+    interface_type* pTmp = reinterpret_cast< Ifc* >(rRef._pInterface);
+    _pInterface = pTmp;
+    if (_pInterface)
+        _pInterface->acquire();
+}
 //__________________________________________________________________________________________________
 template< class interface_type >
 inline void Reference< interface_type >::clear() SAL_THROW(())
@@ -332,6 +341,16 @@
     set( castFromXInterface( rRef._pInterface ) );
     return *this;
 }
+//__________________________________________________________________________________________________
+template< class interface_type >
+template< class Ifc >
+inline Reference< interface_type > & Reference< interface_type >::operator = (
+    const Reference<Ifc>& rRef )
+{
+    interface_type* pTmp = reinterpret_cast< Ifc* >(rRef._pInterface);
+    set( pTmp );
+    return *this;
+}
 
 //__________________________________________________________________________________________________
 template< class interface_type >

-- 
To view, visit https://gerrit.libreoffice.org/3698
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Gerrit-MessageType: newchange
Gerrit-Change-Id: I589b57c0a54524460fc8518a456dc09797c3567a
Gerrit-PatchSet: 1
Gerrit-Project: core
Gerrit-Branch: master
Gerrit-Owner: Thorsten Behrens <tbehrens at suse.com>