simplify "no delete" logic in SvRefBase

by converting the bit munging to use bitfields.
Remove unused return values.
Add asserts to check that AddRef() is not called after the object
is deleted.
Fix the code in SfxObjectShell to not call AddRef() after
SfxObjectShell is deleted.

Change-Id: I3a3565a0bc45fc9d1d086222265ab8b8175818a7

1 files changed, 18 insertions, 17 deletions

diff --git a/include/tools/ref.hxx b/include/tools/ref.hxx
index ed34f4137666..3b8b320c5fe0 100644
--- a/include/tools/ref.hxx
+++ b/include/tools/ref.hxx
@@ -146,46 +146,47 @@ public:
 /** Classes that want to be referenced-counted via SvRef<T>, should extend this base class */
 class TOOLS_DLLPUBLIC SvRefBase
 {
-    static const sal_uIntPtr SV_NO_DELETE_REFCOUNT = 0x80000000;
-    sal_uIntPtr nRefCount;
+    // the only reason this is not bool is because MSVC cannot handle mixed type bitfields
+    unsigned int bNoDelete : 1;
+    unsigned int nRefCount : 31;
 
 protected:
     virtual         ~SvRefBase();
     virtual void    QueryDelete();
 
 public:
-                    SvRefBase()
-                    { nRefCount = SV_NO_DELETE_REFCOUNT; }
+                    SvRefBase() : bNoDelete(1), nRefCount(0) {}
 
-                    SvRefBase( const SvRefBase & /* rObj */ )
-                    { nRefCount = SV_NO_DELETE_REFCOUNT; }
+                    SvRefBase( const SvRefBase & /* rObj */ )  : bNoDelete(1), nRefCount(0) {}
 
     SvRefBase &     operator = ( const SvRefBase & )
                     { return *this; }
 
     void            RestoreNoDelete()
+                    { bNoDelete = 1; }
+
+    void            AddNextRef()
                     {
-                        if( nRefCount < SV_NO_DELETE_REFCOUNT )
-                            nRefCount += SV_NO_DELETE_REFCOUNT;
+                        assert( nRefCount < (1 << 30) && "Do not add refs to dead objects" );
+                        ++nRefCount;
                     }
 
-    sal_uIntPtr     AddNextRef()
-                    { return ++nRefCount; }
-
-    sal_uIntPtr     AddRef()
+    void            AddRef()
                     {
-                        if( nRefCount >= SV_NO_DELETE_REFCOUNT )
-                            nRefCount -= SV_NO_DELETE_REFCOUNT;
-                        return ++nRefCount;
+                        assert( nRefCount < (1 << 30) && "Do not add refs to dead objects" );
+                        if( bNoDelete )
+                            bNoDelete = 0;
+                        ++nRefCount;
                     }
 
     void            ReleaseRef()
                     {
-                        if( !--nRefCount )
+                        assert( nRefCount >= 1);
+                        if( --nRefCount == 0 && !bNoDelete)
                             QueryDelete();
                     }
 
-    sal_uIntPtr     GetRefCount() const
+    unsigned int    GetRefCount() const
                     { return nRefCount; }
 };