Introduce o3tl::optional as an alias for std::optional

...with a boost::optional fallback for Xcode < 10 (as std::optional is only
available starting with Xcode 10 according to
<https://en.cppreference.com/w/cpp/compiler_support>, and our baseline for iOS
and macOS is still Xcode 9.3 according to README.md).  And mechanically rewrite
all code to use o3tl::optional instead of boost::optional.

One immediate benefit is that disabling -Wmaybe-uninitialized for GCC as per
fed7c3deb3f4ec81f78967c2d7f3c4554398cb9d "Slience bogus
-Werror=maybe-uninitialized" should no longer be necessary (and whose check
happened to no longer trigger for GCC 10 trunk, even though that compiler would
still emit bogus -Wmaybe-uninitialized for uses of boost::optional under
--enable-optimized, which made me ponder whether this switch from
boost::optional to std::optional would be a useful thing to do; I keep that
configure.ac check for now, though, and will only remove it in a follow up
commit).

Another longer-term benefit is that the code is now already in good shape for an
eventual switch to std::optional (a switch we would have done anyway once we no
longer need to support Xcode < 10).

Only desktop/qa/desktop_lib/test_desktop_lib.cxx heavily uses
boost::property_tree::ptree::get_child_optional returning boost::optional, so
let it keep using boost::optional for now.

After a number of preceding commits have paved the way for this change, this
commit is completely mechanical, done with

> git ls-files -z | grep -vz -e '^bin/find-unneeded-includes$' -e '^configure.ac$' -e '^desktop/qa/desktop_lib/test_desktop_lib.cxx$' -e '^dictionaries$' -e '^external/' -e '^helpcontent2$' -e '^include/IwyuFilter_include.yaml$' -e '^sc/IwyuFilter_sc.yaml$' -e '^solenv/gdb/boost/optional.py$' -e '^solenv/vs/LibreOffice.natvis$' -e '^translations$' -e '\.svg$' | xargs -0 sed -i -E -e 's|\<boost(/optional)?/optional\.hpp\>|o3tl/optional.hxx|g' -e 's/\<boost(\s*)::(\s*)(make_)?optional\>/o3tl\1::\2\3optional/g' -e 's/\<boost(\s*)::(\s*)none\>/o3tl\1::\2nullopt/g'

(before committing include/o3tl/optional.hxx, and relying on some GNU features).
It excludes some files where mention of boost::optional et al should apparently
not be changed (and the sub-repo directory stubs).  It turned out that all uses
of boost::none across the code base were in combination with boost::optional, so
had all to be rewritten as o3tl::nullopt.

Change-Id: Ibfd9f4b3d5a8aee6e6eed310b988c4e5ffd8b11b
Reviewed-on: https://gerrit.libreoffice.org/84128
Tested-by: Jenkins
Reviewed-by: Stephan Bergmann <sbergman@redhat.com>

7 files changed, 16 insertions, 16 deletions

diff --git a/sd/inc/pch/precompiled_sd.hxx b/sd/inc/pch/precompiled_sd.hxx
index cea2898dfbca..475d59df9c63 100644
--- a/sd/inc/pch/precompiled_sd.hxx
+++ b/sd/inc/pch/precompiled_sd.hxx
@@ -39,8 +39,8 @@
 #include <unordered_map>
 #include <utility>
 #include <vector>
-#include <boost/optional.hpp>
-#include <boost/optional/optional.hpp>
+#include <o3tl/optional.hxx>
+#include <o3tl/optional.hxx>
 #include <boost/property_tree/json_parser.hpp>
 #include <boost/property_tree/ptree.hpp>
 #endif // PCH_LEVEL >= 1
diff --git a/sd/inc/pch/precompiled_sdui.hxx b/sd/inc/pch/precompiled_sdui.hxx
index 0922819f0e6f..bfd2e4bc1858 100644
--- a/sd/inc/pch/precompiled_sdui.hxx
+++ b/sd/inc/pch/precompiled_sdui.hxx
@@ -50,7 +50,7 @@
 #include <typeinfo>
 #include <utility>
 #include <vector>
-#include <boost/optional.hpp>
+#include <o3tl/optional.hxx>
 #include <boost/property_tree/ptree.hpp>
 #endif // PCH_LEVEL >= 1
 #if PCH_LEVEL >= 2
diff --git a/sd/source/filter/ppt/pptin.cxx b/sd/source/filter/ppt/pptin.cxx
index b641545a8aca..cd1d62012a72 100644
--- a/sd/source/filter/ppt/pptin.cxx
+++ b/sd/source/filter/ppt/pptin.cxx
@@ -87,7 +87,7 @@
 #include <comphelper/string.hxx>
 #include <oox/ole/olehelper.hxx>
 
-#include <boost/optional.hpp>
+#include <o3tl/optional.hxx>
 
 #include <cassert>
 #include <memory>
@@ -583,7 +583,7 @@ bool ImplSdPPTImport::Import()
                     pPage->SetAutoLayout( AUTOLAYOUT_NOTES, true );
                 if ( nMasterNum )
                 {
-                    boost::optional< sal_Int16 > oStartNumbering;
+                    o3tl::optional< sal_Int16 > oStartNumbering;
                     SfxStyleSheet* pSheet;
                     if ( nMasterNum == 1 )
                     {
diff --git a/sd/source/ui/app/sdmod2.cxx b/sd/source/ui/app/sdmod2.cxx
index 1a09eb06f44b..5bc72ad5fde9 100644
--- a/sd/source/ui/app/sdmod2.cxx
+++ b/sd/source/ui/app/sdmod2.cxx
@@ -335,7 +335,7 @@ IMPL_LINK(SdModule, CalcFieldValueHdl, EditFieldInfo*, pInfo, void)
     }
     else if ( dynamic_cast< const SdrMeasureField* >(pField))
     {
-        pInfo->SetFieldColor(boost::optional<Color>()); // clear the field color
+        pInfo->SetFieldColor(o3tl::optional<Color>()); // clear the field color
     }
     else if ((pCustomPropertyField = dynamic_cast<const editeng::CustomPropertyField*>(pField)) != nullptr)
     {
diff --git a/sd/source/ui/slidesorter/controller/SlsSelectionFunction.cxx b/sd/source/ui/slidesorter/controller/SlsSelectionFunction.cxx
index 23378029bb91..d54b09a91a90 100644
--- a/sd/source/ui/slidesorter/controller/SlsSelectionFunction.cxx
+++ b/sd/source/ui/slidesorter/controller/SlsSelectionFunction.cxx
@@ -51,7 +51,7 @@
 #include <o3tl/deleter.hxx>
 #include <sfx2/dispatch.hxx>
 #include <vcl/ptrstyle.hxx>
-#include <boost/optional.hpp>
+#include <o3tl/optional.hxx>
 #include <sdmod.hxx>
 
 namespace {
@@ -198,7 +198,7 @@ protected:
     virtual bool ProcessDragEvent (SelectionFunction::EventDescriptor& rDescriptor) override;
 
 private:
-    ::boost::optional<Point> maButtonDownLocation;
+    ::o3tl::optional<Point> maButtonDownLocation;
 
     /** Select all pages between and including the selection anchor and the
         specified page.
@@ -1183,7 +1183,7 @@ void NormalModeHandler::RangeSelect (const model::SharedPageDescriptor& rpDescri
 
 void NormalModeHandler::ResetButtonDownLocation()
 {
-    maButtonDownLocation = ::boost::optional<Point>();
+    maButtonDownLocation = ::o3tl::optional<Point>();
 }
 
 //===== MultiSelectionModeHandler =============================================
diff --git a/sd/source/ui/slidesorter/controller/SlsVisibleAreaManager.cxx b/sd/source/ui/slidesorter/controller/SlsVisibleAreaManager.cxx
index ff16fb0e4dac..b495de5d03d6 100644
--- a/sd/source/ui/slidesorter/controller/SlsVisibleAreaManager.cxx
+++ b/sd/source/ui/slidesorter/controller/SlsVisibleAreaManager.cxx
@@ -107,7 +107,7 @@ void VisibleAreaManager::MakeVisible()
         return;
     const Point aCurrentTopLeft (pWindow->PixelToLogic(Point(0,0)));
 
-    const ::boost::optional<Point> aNewVisibleTopLeft (GetRequestedTopLeft());
+    const ::o3tl::optional<Point> aNewVisibleTopLeft (GetRequestedTopLeft());
     maVisibleRequests.clear();
     if ( ! aNewVisibleTopLeft)
         return;
@@ -121,11 +121,11 @@ void VisibleAreaManager::MakeVisible()
     aAnimation(1.0);
 }
 
-::boost::optional<Point> VisibleAreaManager::GetRequestedTopLeft() const
+::o3tl::optional<Point> VisibleAreaManager::GetRequestedTopLeft() const
 {
     sd::Window *pWindow (mrSlideSorter.GetContentWindow().get());
     if ( ! pWindow)
-        return ::boost::optional<Point>();
+        return ::o3tl::optional<Point>();
 
     // Get the currently visible area and the model area.
     const ::tools::Rectangle aVisibleArea (pWindow->PixelToLogic(
@@ -166,9 +166,9 @@ void VisibleAreaManager::MakeVisible()
 
     const Point aRequestedTopLeft (nVisibleLeft, nVisibleTop);
     if (aRequestedTopLeft == aVisibleArea.TopLeft())
-        return ::boost::optional<Point>();
+        return ::o3tl::optional<Point>();
     else
-        return ::boost::optional<Point>(aRequestedTopLeft);
+        return ::o3tl::optional<Point>(aRequestedTopLeft);
 }
 
 //===== VisibleAreaManager::TemporaryDisabler =================================
diff --git a/sd/source/ui/slidesorter/inc/controller/SlsVisibleAreaManager.hxx b/sd/source/ui/slidesorter/inc/controller/SlsVisibleAreaManager.hxx
index acd74e2b5ffc..8ac72f786ec2 100644
--- a/sd/source/ui/slidesorter/inc/controller/SlsVisibleAreaManager.hxx
+++ b/sd/source/ui/slidesorter/inc/controller/SlsVisibleAreaManager.hxx
@@ -21,7 +21,7 @@
 #define INCLUDED_SD_SOURCE_UI_SLIDESORTER_INC_CONTROLLER_SLSVISIBLEAREAMANAGER_HXX
 
 #include <model/SlsSharedPageDescriptor.hxx>
-#include <boost/optional.hpp>
+#include <o3tl/optional.hxx>
 #include <tools/gen.hxx>
 #include <vector>
 
@@ -81,7 +81,7 @@ private:
     int  mnDisableCount;
 
     void MakeVisible();
-    ::boost::optional<Point> GetRequestedTopLeft() const;
+    ::o3tl::optional<Point> GetRequestedTopLeft() const;
 };
 
 } } } // end of namespace ::sd::slidesorter::view