Remove obsolete "explicit operator bool" hack

...and fix the call sites that exploited the hack's internals being non-
transparent.

Change-Id: Ib3b06c3945e303d4088c4e1b65be5beed8613bac
Reviewed-on: https://gerrit.libreoffice.org/46325Tested-by: Jenkins <ci@libreoffice.org>
Reviewed-by: Stephan Bergmann <sbergman@redhat.com>

filter/source/graphicfilter/ipcx/ipcx.cxx

@@ -100,7 +100,7 @@ bool PCXReader::ReadPCX(Graphic & rGraphic)
     {
         aBmp = Bitmap( Size( nWidth, nHeight ), nDestBitsPerPixel );
         Bitmap::ScopedWriteAccess pAcc(aBmp);
-        if ( pAcc == nullptr )
+        if ( !pAcc )
             return false;
 
         if ( nDestBitsPerPixel <= 8 )

filter/source/graphicfilter/iras/iras.cxx

@@ -174,7 +174,7 @@ bool RASReader::ReadRAS(Graphic & rGraphic)
 
     Bitmap aBmp(Size(mnWidth, mnHeight), mnDstBitsPerPix);
     Bitmap::ScopedWriteAccess pAcc(aBmp);
-    if (pAcc == nullptr)
+    if (!pAcc)
         return false;
 
     if (bPalette)

include/vcl/scopedbitmapaccess.hxx

@@ -45,9 +45,6 @@ namespace vcl
  */
 template < class Access, class Bitmap, Access* (Bitmap::* Acquire)() > class ScopedBitmapAccess
 {
-    typedef ScopedBitmapAccess< Access, Bitmap, Acquire > self_type;
-    typedef bool (self_type::* unspecified_bool_type)() const;
-
 public:
     explicit ScopedBitmapAccess( Bitmap& rBitmap ) :
         mpAccess( nullptr ),
@@ -98,9 +95,9 @@ public:
     }
 
     bool operator!() const { return !mpAccess; }
-    operator unspecified_bool_type() const
+    explicit operator bool() const
     {
-        return mpAccess ? &self_type::operator! : 0;
+        return mpAccess;
     }
 
     Access*         get() { return mpAccess; }

vcl/source/bitmap/BitmapScaleConvolution.cxx

@@ -109,7 +109,7 @@ bool ImplScaleConvolutionHor(Bitmap& rSource, Bitmap& rTarget, const double& rSc
         ImplCalculateContributions(nWidth, nNewWidth, aNumberOfContributions, pWeights, pPixels, pCount, aKernel);
         rTarget = Bitmap(Size(nNewWidth, nHeight), 24);
         Bitmap::ScopedWriteAccess pWriteAcc(rTarget);
-        bool bResult(nullptr != pWriteAcc);
+        bool bResult(pWriteAcc);
 
         if(bResult)
         {
@@ -195,7 +195,7 @@ bool ImplScaleConvolutionVer(Bitmap& rSource, Bitmap& rTarget, const double& rSc
         ImplCalculateContributions(nHeight, nNewHeight, aNumberOfContributions, pWeights, pPixels, pCount, aKernel);
         rTarget = Bitmap(Size(nWidth, nNewHeight), 24);
         Bitmap::ScopedWriteAccess pWriteAcc(rTarget);
-        bool bResult(nullptr != pWriteAcc);
+        bool bResult(pWriteAcc);
 
         if(pWriteAcc)
         {

vcl/source/filter/igif/gifread.cxx

@@ -222,7 +222,7 @@ void GIFReader::CreateBitmaps( long nWidth, long nHeight, BitmapPalette* pPal,
           aBmp8.Erase( Color( COL_WHITE ) );
 
         pAcc8 = Bitmap::ScopedWriteAccess(aBmp8);
-        bStatus = ( pAcc8 != nullptr );
+        bStatus = bool(pAcc8);
     }
 }
 
@@ -685,13 +685,13 @@ Graphic GIFReader::GetIntermediateGraphic()
             aImGraphic = BitmapEx( aBmp8, aBmp1 );
 
             pAcc1 = Bitmap::ScopedWriteAccess(aBmp1);
-            bStatus = bStatus && ( pAcc1 != nullptr );
+            bStatus = bStatus && pAcc1;
         }
         else
             aImGraphic = aBmp8;
 
         pAcc8 = Bitmap::ScopedWriteAccess(aBmp8);
-        bStatus = bStatus && ( pAcc8 != nullptr );
+        bStatus = bStatus && pAcc8;
     }
 
     return aImGraphic;