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, 49 insertions, 0 deletions

diff --git a/sw/inc/BorderCacheOwner.hxx b/sw/inc/BorderCacheOwner.hxx
new file mode 100644
index 000000000000..6819aed3a8ca
--- /dev/null
+++ b/sw/inc/BorderCacheOwner.hxx
@@ -0,0 +1,49 @@
+/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4; fill-column: 100 -*- */
+/*
+ * This file is part of the LibreOffice project.
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/.
+ */
+
+#ifndef INCLUDED_SW_INC_CACHEOWNER_HXX
+#define INCLUDED_SW_INC_CACHEOWNER_HXX
+
+#include <sal/types.h>
+#include "swdllapi.h"
+
+class SwBorderAttrs;
+class SwBorderAttrAccess;
+
+namespace sw
+{
+/// Bookkeeping helper for SwCache caching writer borders.
+class SW_DLLPUBLIC BorderCacheOwner
+{
+private:
+    friend SwBorderAttrs;
+    friend SwBorderAttrAccess;
+    bool m_bInCache;
+
+public:
+    BorderCacheOwner()
+        : m_bInCache(false)
+    {
+    }
+    BorderCacheOwner(BorderCacheOwner&)
+        : m_bInCache(false)
+    {
+    }
+    BorderCacheOwner& operator=(const BorderCacheOwner&)
+    {
+        m_bInCache = false;
+        return *this;
+    }
+    ~BorderCacheOwner();
+    bool IsInCache() const { return m_bInCache; }
+    void InvalidateInSwCache(const sal_uInt16);
+};
+}
+#endif
+/* vim:set shiftwidth=4 softtabstop=4 expandtab: */