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.

Change-Id: I342a7610a107db7d7a344ea9cbddfd9714d7e9ca

6 files changed, 13 insertions, 22 deletions

diff --git a/slideshow/source/engine/activities/activitiesfactory.cxx b/slideshow/source/engine/activities/activitiesfactory.cxx
index c3e026b85986..17868c25761a 100644
--- a/slideshow/source/engine/activities/activitiesfactory.cxx
+++ b/slideshow/source/engine/activities/activitiesfactory.cxx
@@ -764,11 +764,9 @@ AnimationActivitySharedPtr createActivity(
 
             default:
                 OSL_FAIL( "createActivity(): unexpected case" );
-                // FALLTHROUGH intended
+                SAL_FALLTHROUGH;
             case animations::AnimationCalcMode::PACED:
-                // FALLTHROUGH intended
             case animations::AnimationCalcMode::SPLINE:
-                // FALLTHROUGH intended
             case animations::AnimationCalcMode::LINEAR:
                 return createValueListActivity< ContinuousKeyTimeActivityBase >(
                     xNode->getValues(),
@@ -832,11 +830,9 @@ AnimationActivitySharedPtr createActivity(
 
             default:
                 OSL_FAIL( "createActivity(): unexpected case" );
-                // FALLTHROUGH intended
+                SAL_FALLTHROUGH;
             case animations::AnimationCalcMode::PACED:
-                // FALLTHROUGH intended
             case animations::AnimationCalcMode::SPLINE:
-                // FALLTHROUGH intended
             case animations::AnimationCalcMode::LINEAR:
                 return createFromToByActivity< ContinuousActivityBase >(
                     xNode->getFrom(),
diff --git a/slideshow/source/engine/animationnodes/basenode.cxx b/slideshow/source/engine/animationnodes/basenode.cxx
index 9b7bae8cca47..a1467a5db0e7 100644
--- a/slideshow/source/engine/animationnodes/basenode.cxx
+++ b/slideshow/source/engine/animationnodes/basenode.cxx
@@ -203,7 +203,7 @@ const int* getStateTransitionTable( sal_Int16 nRestartMode,
         // same value: animations::AnimationRestart::INHERIT:
         OSL_FAIL(
             "getStateTransitionTable(): unexpected case for restart" );
-        // FALLTHROUGH intended
+        SAL_FALLTHROUGH;
     case animations::AnimationRestart::NEVER:
         nRestartValue = 0;
         break;
@@ -223,7 +223,7 @@ const int* getStateTransitionTable( sal_Int16 nRestartMode,
         // same value: animations::AnimationFill::INHERIT:
         OSL_FAIL(
             "getStateTransitionTable(): unexpected case for fill" );
-        // FALLTHROUGH intended
+        SAL_FALLTHROUGH;
     case animations::AnimationFill::REMOVE:
         nFillValue = 0;
         break;
diff --git a/slideshow/source/engine/animationnodes/generateevent.cxx b/slideshow/source/engine/animationnodes/generateevent.cxx
index 76a778c4acec..513f0bc889b3 100644
--- a/slideshow/source/engine/animationnodes/generateevent.cxx
+++ b/slideshow/source/engine/animationnodes/generateevent.cxx
@@ -188,7 +188,7 @@ EventSharedPtr generateEvent(
         case animations::EventTrigger::ON_PREV:
             OSL_FAIL( "event trigger ON_PREV not yet implemented, "
                         "mapped to ON_NEXT!" );
-            // FALLTHROUGH intended
+            SAL_FALLTHROUGH;
         case animations::EventTrigger::ON_NEXT:
             pEvent = makeDelay( rFunctor,
                                 nDelay2 + nAdditionalDelay,
diff --git a/slideshow/source/engine/shapes/drawshapesubsetting.cxx b/slideshow/source/engine/shapes/drawshapesubsetting.cxx
index 588f6cc47613..d8a1ad127f55 100644
--- a/slideshow/source/engine/shapes/drawshapesubsetting.cxx
+++ b/slideshow/source/engine/shapes/drawshapesubsetting.cxx
@@ -152,7 +152,7 @@ namespace slideshow
                         SAL_INFO("slideshow.verbose", "Shape text \"" <<
                                  (static_cast<MetaTextAction*>(pCurrAct))->GetText() <<
                                  "\" at action #" << nActionIndex );
-                        // fallthrough intended
+                        SAL_FALLTHROUGH;
                     default:
                         // comment action and all actions not
                         // explicitly handled here:
@@ -504,8 +504,7 @@ namespace slideshow
                             }
 
                             ++nCurrShapeCount;
-                            // FALLTHROUGH intended: shape end also
-                            // ends lines
+                            SAL_FALLTHROUGH; // shape end also ends lines
                         case DrawShapeSubsetting::CLASS_PARAGRAPH_END:
                             if( !io_rFunctor( DrawShapeSubsetting::CLASS_PARAGRAPH_END,
                                               nCurrParaCount,
@@ -517,8 +516,7 @@ namespace slideshow
 
                             ++nCurrParaCount;
                             aLastParaStart = aNext;
-                            // FALLTHROUGH intended: para end also
-                            // ends line
+                            SAL_FALLTHROUGH; // para end also ends line
                         case DrawShapeSubsetting::CLASS_LINE_END:
                             if( !io_rFunctor( DrawShapeSubsetting::CLASS_LINE_END,
                                               nCurrLineCount,
@@ -545,7 +543,7 @@ namespace slideshow
                                 // character cell, OTOH?
                                 break;
                             }
-                            // FALLTHROUGH intended
+                            SAL_FALLTHROUGH;
                         case DrawShapeSubsetting::CLASS_SENTENCE_END:
                             if( !io_rFunctor( DrawShapeSubsetting::CLASS_SENTENCE_END,
                                               nCurrSentenceCount,
@@ -557,7 +555,7 @@ namespace slideshow
 
                             ++nCurrSentenceCount;
                             aLastSentenceStart = aNext;
-                            // FALLTHROUGH intended
+                            SAL_FALLTHROUGH;
                         case DrawShapeSubsetting::CLASS_WORD_END:
                             if( !io_rFunctor( DrawShapeSubsetting::CLASS_WORD_END,
                                               nCurrWordCount,
@@ -569,7 +567,7 @@ namespace slideshow
 
                             ++nCurrWordCount;
                             aLastWordStart = aNext;
-                            // FALLTHROUGH intended
+                            SAL_FALLTHROUGH;
                         case DrawShapeSubsetting::CLASS_CHARACTER_CELL_END:
                             if( !io_rFunctor( DrawShapeSubsetting::CLASS_CHARACTER_CELL_END,
                                               nCurrCharCount,
diff --git a/slideshow/source/engine/shapes/gdimtftools.cxx b/slideshow/source/engine/shapes/gdimtftools.cxx
index 684c07a57617..19fc0015b6a4 100644
--- a/slideshow/source/engine/shapes/gdimtftools.cxx
+++ b/slideshow/source/engine/shapes/gdimtftools.cxx
@@ -86,11 +86,9 @@ bool hasUnsupportedActions( const GDIMetaFile& rMtf )
                 {
                     break;
                 }
-                // FALLTHROUGH intended
+                SAL_FALLTHROUGH;
             case MetaActionType::MOVECLIPREGION:
-                // FALLTHROUGH intended
             case MetaActionType::REFPOINT:
-                // FALLTHROUGH intended
             case MetaActionType::WALLPAPER:
                 return true; // at least one unsupported
                              // action encountered
diff --git a/slideshow/source/engine/slide/targetpropertiescreator.cxx b/slideshow/source/engine/slide/targetpropertiescreator.cxx
index 8974acdc4b17..6eb1f70b5cdc 100644
--- a/slideshow/source/engine/slide/targetpropertiescreator.cxx
+++ b/slideshow/source/engine/slide/targetpropertiescreator.cxx
@@ -168,10 +168,9 @@ namespace internal
                                 return;
                             }
                         }
+                        SAL_FALLTHROUGH;
                     }
-                        // FALLTHROUGH intended
                     case animations::AnimationNodeType::PAR:
-                        // FALLTHROUGH intended
                     case animations::AnimationNodeType::SEQ:
                     {
                         /// forward bInitial