Replace fallthrough comments with new SAL_FALLTHROUGH macro

...which (in LIBO_INTERNAL_ONLY) for Clang expands to [[clang::fallthrough]] in
preparation of enabling -Wimplicit-fallthrough.  (This is only relevant for
C++11, as neither C nor old C++ has a way to annotate intended fallthroughs.)

Could use BOOST_FALLTHROUGH instead of introducing our own SAL_FALLTHROUGH, but
that would require adding back in dependencies on boost_headers to many
libraries where we carefully removed any remaining Boost dependencies only
recently.  (At least make SAL_FALLTHROUGH strictly LIBO_INTERNAL_ONLY, so its
future evolution will not have any impact on the stable URE interface.)  C++17
will have a proper [[fallthroug]], eventually removing the need for a macro
altogether.

(cherry picked from commit 14cd5182c5f64c43581c82db8c958369152226ac)

Change-Id: I342a7610a107db7d7a344ea9cbddfd9714d7e9ca

9 files changed, 29 insertions, 21 deletions

diff --git a/vcl/source/control/edit.cxx b/vcl/source/control/edit.cxx
index 5fb666e01122..523e12a30070 100644
--- a/vcl/source/control/edit.cxx
+++ b/vcl/source/control/edit.cxx
@@ -1589,7 +1589,7 @@ bool Edit::ImplHandleKeyEvent( const KeyEvent& rKEvt )
                     case css::awt::Key::SELECT_TO_BEGIN_OF_PARAGRAPH:
                     case css::awt::Key::SELECT_TO_BEGIN_OF_DOCUMENT:
                         bSelect = true;
-                        // fallthrough intended
+                        SAL_FALLTHROUGH;
                     case css::awt::Key::MOVE_TO_BEGIN_OF_LINE:
                     case css::awt::Key::MOVE_TO_BEGIN_OF_PARAGRAPH:
                     case css::awt::Key::MOVE_TO_BEGIN_OF_DOCUMENT:
@@ -1598,7 +1598,7 @@ bool Edit::ImplHandleKeyEvent( const KeyEvent& rKEvt )
                     case css::awt::Key::SELECT_TO_END_OF_PARAGRAPH:
                     case css::awt::Key::SELECT_TO_END_OF_DOCUMENT:
                         bSelect = true;
-                        // fallthrough intended
+                        SAL_FALLTHROUGH;
                     case css::awt::Key::MOVE_TO_END_OF_LINE:
                     case css::awt::Key::MOVE_TO_END_OF_PARAGRAPH:
                     case css::awt::Key::MOVE_TO_END_OF_DOCUMENT:
diff --git a/vcl/source/edit/textview.cxx b/vcl/source/edit/textview.cxx
index 1baddd57b150..1db0da853d3b 100644
--- a/vcl/source/edit/textview.cxx
+++ b/vcl/source/edit/textview.cxx
@@ -1265,42 +1265,50 @@ TextSelection TextView::ImpMoveCursor( const KeyEvent& rKeyEvent )
         case KEY_RIGHT:     aPaM = bCtrl ? CursorWordRight( aPaM ) : CursorRight( aPaM, aTranslatedKeyEvent.GetKeyCode().IsMod2() ? (sal_uInt16)i18n::CharacterIteratorMode::SKIPCHARACTER : (sal_uInt16)i18n::CharacterIteratorMode::SKIPCELL );
                             break;
         case css::awt::Key::SELECT_WORD_FORWARD:
-                            bSelect = true; // fallthrough intentional
+                            bSelect = true;
+                            SAL_FALLTHROUGH;
         case css::awt::Key::MOVE_WORD_FORWARD:
                             aPaM = CursorWordRight( aPaM );
                             break;
         case css::awt::Key::SELECT_WORD_BACKWARD:
-                            bSelect = true; // fallthrough intentional
+                            bSelect = true;
+                            SAL_FALLTHROUGH;
         case css::awt::Key::MOVE_WORD_BACKWARD:
                             aPaM = CursorWordLeft( aPaM );
                             break;
         case css::awt::Key::SELECT_TO_BEGIN_OF_LINE:
-                            bSelect = true; // fallthrough intentional
+                            bSelect = true;
+                            SAL_FALLTHROUGH;
         case css::awt::Key::MOVE_TO_BEGIN_OF_LINE:
                             aPaM = CursorStartOfLine( aPaM );
                             break;
         case css::awt::Key::SELECT_TO_END_OF_LINE:
-                            bSelect = true; // fallthrough intentional
+                            bSelect = true;
+                            SAL_FALLTHROUGH;
         case css::awt::Key::MOVE_TO_END_OF_LINE:
                             aPaM = CursorEndOfLine( aPaM );
                             break;
         case css::awt::Key::SELECT_TO_BEGIN_OF_PARAGRAPH:
-                            bSelect = true; // falltthrough intentional
+                            bSelect = true;
+                            SAL_FALLTHROUGH;
         case css::awt::Key::MOVE_TO_BEGIN_OF_PARAGRAPH:
                             aPaM = CursorStartOfParagraph( aPaM );
                             break;
         case css::awt::Key::SELECT_TO_END_OF_PARAGRAPH:
-                            bSelect = true; // falltthrough intentional
+                            bSelect = true;
+                            SAL_FALLTHROUGH;
         case css::awt::Key::MOVE_TO_END_OF_PARAGRAPH:
                             aPaM = CursorEndOfParagraph( aPaM );
                             break;
         case css::awt::Key::SELECT_TO_BEGIN_OF_DOCUMENT:
-                            bSelect = true; // falltthrough intentional
+                            bSelect = true;
+                            SAL_FALLTHROUGH;
         case css::awt::Key::MOVE_TO_BEGIN_OF_DOCUMENT:
                             aPaM = CursorStartOfDoc();
                             break;
         case css::awt::Key::SELECT_TO_END_OF_DOCUMENT:
-                            bSelect = true; // falltthrough intentional
+                            bSelect = true;
+                            SAL_FALLTHROUGH;
         case css::awt::Key::MOVE_TO_END_OF_DOCUMENT:
                             aPaM = CursorEndOfDoc();
                             break;
diff --git a/vcl/source/fontsubset/cff.cxx b/vcl/source/fontsubset/cff.cxx
index 3a46f474e00b..54af9444fd81 100644
--- a/vcl/source/fontsubset/cff.cxx
+++ b/vcl/source/fontsubset/cff.cxx
@@ -1002,7 +1002,7 @@ void CffSubsetterContext::convertOneTypeEsc()
         assert( mnStackIdx >= 1 );
         if( pTop[0] >= 0)
             break;
-        // fall through
+        SAL_FALLTHROUGH;
     case TYPE2OP::NEG:
         assert( mnStackIdx >= 1 );
         pTop[0] = -pTop[0];
diff --git a/vcl/source/fontsubset/xlat.cxx b/vcl/source/fontsubset/xlat.cxx
index 408e6b1aef22..6fc4cb7b6559 100644
--- a/vcl/source/fontsubset/xlat.cxx
+++ b/vcl/source/fontsubset/xlat.cxx
@@ -68,7 +68,7 @@ void ConverterCache::ensureConverter( int nSelect )
         rtl_TextEncoding eRecodeFrom = RTL_TEXTENCODING_UNICODE;
         switch( nSelect )
         {
-            default: nSelect = 1; // fall through to unicode recoding
+            default: nSelect = 1; SAL_FALLTHROUGH; // to unicode recoding
             case 1: eRecodeFrom = RTL_TEXTENCODING_UNICODE; break;
             case 2: eRecodeFrom = RTL_TEXTENCODING_SHIFT_JIS; break;
             case 3: eRecodeFrom = RTL_TEXTENCODING_GB_2312; break;
diff --git a/vcl/source/gdi/pdfwriter_impl.cxx b/vcl/source/gdi/pdfwriter_impl.cxx
index e576f2a5c028..e667cb23ec41 100644
--- a/vcl/source/gdi/pdfwriter_impl.cxx
+++ b/vcl/source/gdi/pdfwriter_impl.cxx
@@ -5388,7 +5388,7 @@ bool PDFWriterImpl::emitWidgetAnnotations()
                         else
                             appendName( rWidget.m_aValue, aValue );
                     }
-                    // fall-through
+                    SAL_FALLTHROUGH;
                 case PDFWriter::PushButton:
                     aLine.append( "Btn" );
                     break;
@@ -10980,7 +10980,7 @@ bool PDFWriterImpl::writeGradientFunction( GradientEmit& rObject )
             aCol[1] = rObject.m_aGradient.GetEndColor().GetGreen();
             aCol[2] = rObject.m_aGradient.GetEndColor().GetBlue();
             CHECK_RETURN( writeBuffer( aCol, 3 ) );
-            // fall-through
+            SAL_FALLTHROUGH;
         case GradientStyle_LINEAR:
         {
             aCol[0] = rObject.m_aGradient.GetStartColor().GetRed();
diff --git a/vcl/source/gdi/pngread.cxx b/vcl/source/gdi/pngread.cxx
index 8af9f0b200d0..1eb2663096ce 100644
--- a/vcl/source/gdi/pngread.cxx
+++ b/vcl/source/gdi/pngread.cxx
@@ -513,7 +513,7 @@ bool PNGReaderImpl::ImplReadHeader( const Size& rPreviewSizeHint )
                     break;
                 case 16 :
                     mnTargetDepth = 8;  // we have to reduce the bitmap
-                    // fall through
+                    SAL_FALLTHROUGH;
                 case 1 :
                 case 4 :
                 case 8 :
@@ -547,7 +547,7 @@ bool PNGReaderImpl::ImplReadHeader( const Size& rPreviewSizeHint )
             {
                 case 2 :
                     mnTargetDepth = 4;  // we have to expand the bitmap
-                    // fall through
+                    SAL_FALLTHROUGH;
                 case 1 :
                 case 4 :
                 case 8 :
diff --git a/vcl/source/window/decoview.cxx b/vcl/source/window/decoview.cxx
index 538c6b1d9573..0f623ebdc8a4 100644
--- a/vcl/source/window/decoview.cxx
+++ b/vcl/source/window/decoview.cxx
@@ -256,7 +256,7 @@ void ImplDrawSymbol( OutputDevice* pDev, Rectangle nRect, const SymbolType eType
             pDev->DrawLine( Point( nRect.Left(), aCenter.Y()-n2+1 ),
                             Point( nRect.Left(), aCenter.Y()+n2-1 ) );
             ++nRect.Left();
-            // Intentional fall-through
+            SAL_FALLTHROUGH;
         case SymbolType::WINDBACKWARD:
             pDev->DrawPixel( Point( nRect.Left(), aCenter.Y() ) );
             pDev->DrawPixel( Point( nRect.Left()+n2, aCenter.Y() ) );
@@ -274,7 +274,7 @@ void ImplDrawSymbol( OutputDevice* pDev, Rectangle nRect, const SymbolType eType
             pDev->DrawLine( Point( nRect.Right(), aCenter.Y()-n2+1 ),
                             Point( nRect.Right(), aCenter.Y()+n2-1 ) );
             --nRect.Right();
-            // Intentional fall-through
+            SAL_FALLTHROUGH;
         case SymbolType::WINDFORWARD:
             pDev->DrawPixel( Point( nRect.Right(), aCenter.Y() ) );
             pDev->DrawPixel( Point( nRect.Right()-n2, aCenter.Y() ) );
@@ -313,7 +313,7 @@ void ImplDrawSymbol( OutputDevice* pDev, Rectangle nRect, const SymbolType eType
                             Point( nRect.Right(), nRect.Bottom() ) );
             pDev->DrawLine( Point( nRect.Left(), nRect.Bottom() ),
                             Point( nRect.Right(), nRect.Bottom() ) );
-            // Intentional fall-through
+            SAL_FALLTHROUGH;
         case SymbolType::ROLLUP:
             pDev->DrawRect( Rectangle( nRect.Left(), nRect.Top(),
                                        nRect.Right(), nRect.Top()+n8 ) );
diff --git a/vcl/source/window/layout.cxx b/vcl/source/window/layout.cxx
index e4efb2667270..7d0ea1544ac6 100644
--- a/vcl/source/window/layout.cxx
+++ b/vcl/source/window/layout.cxx
@@ -603,7 +603,7 @@ void VclButtonBox::setAllocation(const Size &rAllocation)
             break;
         default:
             SAL_WARN("vcl.layout", "todo unimplemented layout style");
-            //fall-through
+            SAL_FALLTHROUGH;
         case VCL_BUTTONBOX_DEFAULT_STYLE:
         case VCL_BUTTONBOX_END:
             if (!aReq.m_aMainGroupDimensions.empty())
diff --git a/vcl/source/window/winproc.cxx b/vcl/source/window/winproc.cxx
index 599bd9fcd4db..6fa8dde994b9 100644
--- a/vcl/source/window/winproc.cxx
+++ b/vcl/source/window/winproc.cxx
@@ -2609,7 +2609,7 @@ bool ImplWindowFrameProc( vcl::Window* _pWindow, SalFrame* /*pFrame*/,
             ImplHandleSurroundingTextSelectionChange( pWindow,
                               pEvt->mnStart,
                               pEvt->mnEnd );
-            // Fallthrough really intended?
+            SAL_FALLTHROUGH; // TODO: Fallthrough really intended?
         }
         case SALEVENT_STARTRECONVERSION:
             ImplHandleStartReconversion( pWindow );