fdo#46071: Do not hide windows based on nil "Visible" property

This appears to be messy:  The /org.openoffice.Office.Views/WindowType
configuration group template has both a nilable bool "Visible" property and a
UserData/Data string property that encodes various things like geometry---but
also visibility---in a string.

Now, likely due to the problem that has meanwhile been fixed through
f3f79cc9e6c265baf48955d53f7e888205e0b3e0 "Resolves fdo#46074: Fix
Partial::contains for paths that go past a leaf node," some
registrymodification.xcu files in the wild contain such WindowType entries in
"default" state, without a UserData/Data string and with a nil "Visible"
property.

The way SfxChildWindow::InitializeChildWinFactory_Impl and
SvtViewOptions::IsVisible are implemented, they will always lead to an invisible
window for such broken registrymodification.xcu data (as IsVisible unhelpfully
returns false for a nil value, and InitializeChildWinFactory_Impl uses that
value when there is no UserData/Data string).

For the Math formula editor window (ID 30378) this means that it can disappear
from the UI completely, as there appears to be no UI trigger for the user to
show it in case it is hidden.

The fix is to introdue SvtViewOptions::HasVisible (which only returns true if
the property is not nil) and change InitializeChidlWinFactory_Impl to only use
the value of IsVisible() if HasVisible() returns true.  This makes the code even
more baroque, but this is a rather central, generic piece of code for all sorts
of windows, so I do not want to break any other uses by e.g. changing IsVisible
to return true for a nil property.

Change-Id: Iae40075a7116a8aabd2d25aa9334709522e23d8f

3 files changed, 41 insertions, 8 deletions

diff --git a/sfx2/source/appl/childwin.cxx b/sfx2/source/appl/childwin.cxx
index 18038dac690c..e1e24be242c0 100644
--- a/sfx2/source/appl/childwin.cxx
+++ b/sfx2/source/appl/childwin.cxx
@@ -352,7 +352,7 @@ void SfxChildWindow::InitializeChildWinFactory_Impl( sal_uInt16 nId, SfxChildWin
     // load configuration
     SvtViewOptions aWinOpt( E_WINDOW, String::CreateFromInt32( nId ) );
 
-    if ( aWinOpt.Exists() )
+    if ( aWinOpt.Exists() && aWinOpt.HasVisible() )
         rInfo.bVisible  = aWinOpt.IsVisible(); // set state from configuration. Can be overwritten by UserData, see below
 
     ::com::sun::star::uno::Sequence < ::com::sun::star::beans::NamedValue > aSeq = aWinOpt.GetUserData();
diff --git a/unotools/inc/unotools/viewoptions.hxx b/unotools/inc/unotools/viewoptions.hxx
index 2dbfdd485a38..8270ed9ef933 100644
--- a/unotools/inc/unotools/viewoptions.hxx
+++ b/unotools/inc/unotools/viewoptions.hxx
@@ -225,6 +225,13 @@ class UNOTOOLS_DLLPUBLIC SvtViewOptions: public utl::detail::Options
         sal_Bool IsVisible (                 ) const;
         void     SetVisible( sal_Bool bState );
 
+        /** Return true if the "Visible" property actually has a non-nil value
+
+            (IsVisible will somewhat arbitrarily return false if the property is
+            nil.)
+        */
+        bool HasVisible() const;
+
         /*-****************************************************************************************************//**
             @short      use it to set/get the extended user data (consisting of a set of named scalar values)
             @descr      It's supported for ALL types!
diff --git a/unotools/source/config/viewoptions.cxx b/unotools/source/config/viewoptions.cxx
index faf59372bf4f..2b4ffbc3add1 100644
--- a/unotools/source/config/viewoptions.cxx
+++ b/unotools/source/config/viewoptions.cxx
@@ -266,6 +266,8 @@ class SvtViewOptionsBase_Impl
 {
     //-------------------------------------------------------------------------------------------------------------
     public:
+        enum State { STATE_NONE, STATE_FALSE, STATE_TRUE };
+
                                                         SvtViewOptionsBase_Impl ( const ::rtl::OUString&                                sList    );
         virtual                                        ~SvtViewOptionsBase_Impl (                                                                );
         sal_Bool                                        Exists                  ( const ::rtl::OUString&                                sName    );
@@ -279,7 +281,7 @@ class SvtViewOptionsBase_Impl
         sal_Int32                                       GetPageID               ( const ::rtl::OUString&                                sName    );
         void                                            SetPageID               ( const ::rtl::OUString&                                sName    ,
                                                                                         sal_Int32                                       nID      );
-        sal_Bool                                        GetVisible              ( const ::rtl::OUString&                                sName    );
+        State                                           GetVisible              ( const ::rtl::OUString&                                sName    );
         void                                            SetVisible              ( const ::rtl::OUString&                                sName    ,
                                                                                         sal_Bool                                        bVisible );
         css::uno::Any                                   GetUserItem             ( const ::rtl::OUString&                                sName    ,
@@ -682,28 +684,33 @@ void SvtViewOptionsBase_Impl::SetPageID( const ::rtl::OUString& sName ,
 }
 
 //*****************************************************************************************************************
-sal_Bool SvtViewOptionsBase_Impl::GetVisible( const ::rtl::OUString& sName )
+SvtViewOptionsBase_Impl::State SvtViewOptionsBase_Impl::GetVisible( const ::rtl::OUString& sName )
 {
     #ifdef DEBUG_VIEWOPTIONS
     ++m_nReadCount;
     #endif
 
-    sal_Bool bVisible = sal_False;
+    State eState = STATE_NONE;
     try
     {
         css::uno::Reference< css::beans::XPropertySet > xNode(
             impl_getSetNode(sName, sal_False),
             css::uno::UNO_QUERY);
         if (xNode.is())
-            xNode->getPropertyValue(PROPERTY_VISIBLE) >>= bVisible;
+        {
+            sal_Bool bVisible = sal_False;
+            if (xNode->getPropertyValue(PROPERTY_VISIBLE) >>= bVisible)
+            {
+                eState = bVisible ? STATE_TRUE : STATE_FALSE;
+            }
+        }
     }
     catch(const css::uno::Exception& ex)
         {
-            bVisible = sal_False;
             SVTVIEWOPTIONS_LOG_UNEXPECTED_EXCEPTION(ex)
         }
 
-    return bVisible;
+    return eState;
 }
 
 //*****************************************************************************************************************
@@ -1055,7 +1062,7 @@ sal_Bool SvtViewOptions::IsVisible() const
 
     sal_Bool bState = sal_False;
     if( m_eViewType == E_WINDOW )
-        bState = m_pDataContainer_Windows->GetVisible( m_sViewName );
+        bState = m_pDataContainer_Windows->GetVisible( m_sViewName ) == SvtViewOptionsBase_Impl::STATE_TRUE;
 
     return bState;
 }
@@ -1077,6 +1084,25 @@ void SvtViewOptions::SetVisible( sal_Bool bState )
 }
 
 //*****************************************************************************************************************
+//  public method
+//*****************************************************************************************************************
+bool SvtViewOptions::HasVisible() const
+{
+    // Ready for multithreading
+    ::osl::MutexGuard aGuard( GetOwnStaticMutex() );
+
+    // Safe impossible cases.
+    // These call isn't allowed for dialogs, tab-dialogs or tab-pages!
+    OSL_ENSURE( !(m_eViewType==E_DIALOG||m_eViewType==E_TABDIALOG||m_eViewType==E_TABPAGE), "SvtViewOptions::IsVisible()\nCall not allowed for Dialogs, TabDialogs or TabPages! I do nothing!\n" );
+
+    bool bState = false;
+    if( m_eViewType == E_WINDOW )
+        bState = m_pDataContainer_Windows->GetVisible( m_sViewName ) != SvtViewOptionsBase_Impl::STATE_NONE;
+
+    return bState;
+}
+
+//*****************************************************************************************************************
 css::uno::Sequence< css::beans::NamedValue > SvtViewOptions::GetUserData() const
 {
     // Ready for multithreading