remove SwCache bookkeeping from SwModify

- only very few classes (SwNode, SwFormat) are the "owners"
of SwBorderAttrs in the SwCache
- this bookkeeping should not be in such a fundamental class of writer
- also: encapsulate most of the interaction with the cache in the new
sw::BorderCacheOwner. This is mostly to protect the innocent user:
* As interacting with the SwCache directly is very errorprone, because
its glorious idea of using void* of the "owners" as keys to the
entries.
* In C++, reinterpret_cast<void*>(this) might be different along the
class heirachy. This might easily slip under the radar of a casual
user.

Change-Id: I0da774b47885abf52f63aab8d93ebbf41dcf8040
Reviewed-on: https://gerrit.libreoffice.org/c/core/+/110112
Tested-by: Jenkins
Reviewed-by: Bjoern Michaelsen <bjoern.michaelsen@libreoffice.org>

1 files changed, 4 insertions, 2 deletions

diff --git a/sw/inc/format.hxx b/sw/inc/format.hxx
index f1e301ba50d0..29c3fab36033 100644
--- a/sw/inc/format.hxx
+++ b/sw/inc/format.hxx
@@ -20,9 +20,11 @@
 #define INCLUDED_SW_INC_FORMAT_HXX
 
 #include "swdllapi.h"
-#include "swatrset.hxx"
+
+#include "BorderCacheOwner.hxx"
 #include "calbck.hxx"
 #include "hintids.hxx"
+#include "swatrset.hxx"
 #include <memory>
 
 class IDocumentSettingAccess;
@@ -41,7 +43,7 @@ namespace drawinglayer::attribute {
 }
 
 /// Base class for various Writer styles.
-class SW_DLLPUBLIC SwFormat : public sw::BroadcastingModify
+class SW_DLLPUBLIC SwFormat : public sw::BorderCacheOwner, public sw::BroadcastingModify
 {
     friend class SwFrameFormat;