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diff --git a/sw/source/core/inc/swcache.hxx b/sw/source/core/inc/swcache.hxx
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+/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
+/*
+ * 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/.
+ *
+ * This file incorporates work covered by the following license notice:
+ *
+ *   Licensed to the Apache Software Foundation (ASF) under one or more
+ *   contributor license agreements. See the NOTICE file distributed
+ *   with this work for additional information regarding copyright
+ *   ownership. The ASF licenses this file to you under the Apache
+ *   License, Version 2.0 (the "License"); you may not use this file
+ *   except in compliance with the License. You may obtain a copy of
+ *   the License at http://www.apache.org/licenses/LICENSE-2.0 .
+ */
+#ifndef INCLUDED_SW_SOURCE_CORE_INC_SWCACHE_HXX
+#define INCLUDED_SW_SOURCE_CORE_INC_SWCACHE_HXX
+
+/**
+ * Here, we manage pointers in a simple PtrArray to objects.
+ * These objects are created (using new) in cache access classes; they are
+ * destroyed by the cache.
+ *
+ * One can access these objects by array index or by searching in the array.
+ * If you access it by index, managing the index is the responsibility of
+ * the cache user.
+ *
+ * The cached objects are derived from the base class SwCacheObj.
+ * In it, the cache objects are doubly-linked which allows for the use of
+ * an LRU algorithm.
+ *
+ * The LRU algorithm can be changed in the base class, by setting a virtual
+ * First Pointer. It can be set to the first real one plus an offset.
+ * By doing so we can protect the start area of the cache and make sure we
+ * don't mess up the cache during some special operations.
+ * E.g.: the Idle Handler should not destroy the cache for the visible area.
+ *
+ * The cache can be grown and shrunk in size.
+ * E.g.: The cache for FormatInfo is grown for every new Shell and shrunk
+ * when destroying them.
+ */
+
+#include <memory>
+#include <vector>
+
+#include <rtl/string.hxx>
+
+class SwCacheObj;
+
+class SwCache
+{
+    std::vector<std::unique_ptr<SwCacheObj>> m_aCacheObjects;
+    std::vector<sal_uInt16> m_aFreePositions; /// Free positions for the Insert if the maximum has not been reached
+                                            /// Every time an object is deregistered, its position is added here
+    SwCacheObj *m_pRealFirst;                 /// _ALWAYS_ the real first LRU
+    SwCacheObj *m_pFirst;                     /// The virtual first
+    SwCacheObj *m_pLast;
+
+    sal_uInt16 m_nCurMax;                     // Maximum of accepted objects
+
+    void DeleteObj( SwCacheObj *pObj );
+
+#ifdef DBG_UTIL
+    OString m_aName;
+    long m_nAppend;           /// number of entries appended
+    long m_nInsertFree;       /// number of entries inserted on freed position
+    long m_nReplace;          /// number of LRU replacements
+    long m_nGetSuccess;
+    long m_nGetFail;
+    long m_nToTop;            /// number of reordering (LRU)
+    long m_nDelete;           /// number of explicit deletes
+    long m_nGetSeek;          /// number of gets without index
+    long m_nAverageSeekCnt;   /// number of seeks for all gets without index
+    long m_nFlushCnt;         /// number of flush calls
+    long m_nFlushedObjects;
+    long m_nIncreaseMax;      /// number of cache size increases
+    long m_nDecreaseMax;      /// number of cache size decreases
+
+    void Check();
+#endif
+
+public:
+
+// Only add sal_uInt8!!!
+#ifdef DBG_UTIL
+    SwCache( const sal_uInt16 nInitSize, const OString &rNm );
+#else
+    SwCache( const sal_uInt16 nInitSize );
+#endif
+    /// The dtor will free all objects still in the vector
+    ~SwCache();
+
+    void Flush();
+
+    //bToTop == false -> No LRU resorting!
+    SwCacheObj *Get( const void *pOwner, const bool bToTop = true );
+    SwCacheObj *Get( const void *pOwner, const sal_uInt16 nIndex,
+                     const bool bToTop = true );
+    void ToTop( SwCacheObj *pObj );
+
+    bool Insert(SwCacheObj *pNew, bool isDuplicateOwnerAllowed);
+    void Delete(const void * pOwner, sal_uInt16 nIndex);
+    void Delete( const void *pOwner );
+
+    void SetLRUOfst( const sal_uInt16 nOfst );  /// nOfst determines how many are not to be touched
+    void ResetLRUOfst() { m_pFirst = m_pRealFirst; }
+
+    void IncreaseMax( const sal_uInt16 nAdd );
+    void DecreaseMax( const sal_uInt16 nSub );
+    sal_uInt16 GetCurMax() const { return m_nCurMax; }
+    SwCacheObj *First() { return m_pRealFirst; }
+    static inline SwCacheObj *Next( SwCacheObj *pCacheObj);
+    SwCacheObj* operator[](sal_uInt16 nIndex) { return m_aCacheObjects[nIndex].get(); }
+    sal_uInt16 size() { return m_aCacheObjects.size(); }
+};
+
+/// Try to prevent visible SwParaPortions from being deleted.
+class SwSaveSetLRUOfst
+{
+public:
+    SwSaveSetLRUOfst();
+    ~SwSaveSetLRUOfst();
+};
+
+/**
+ * The Cache object base class
+ * Users of the Cache must derive a class from the SwCacheObj and store
+ * their payload there
+ */
+class SwCacheObj
+{
+    friend class SwCache;   /// Can do everything
+
+    SwCacheObj *m_pNext;      /// For the LRU chaining
+    SwCacheObj *m_pPrev;
+
+    sal_uInt16 m_nCachePos;   /// Position in the Cache array
+
+    sal_uInt8       m_nLock;
+
+    SwCacheObj *GetNext() { return m_pNext; }
+    SwCacheObj *GetPrev() { return m_pPrev; }
+    void SetNext( SwCacheObj *pNew )  { m_pNext = pNew; }
+    void SetPrev( SwCacheObj *pNew )  { m_pPrev = pNew; }
+
+    void SetCachePos(const sal_uInt16 nNew)
+    {
+        if (m_nCachePos != nNew)
+        {
+            m_nCachePos = nNew;
+            UpdateCachePos();
+        }
+    }
+    virtual void UpdateCachePos() { }
+
+protected:
+    const void *m_pOwner;
+
+public:
+
+    SwCacheObj( const void *pOwner );
+    virtual ~SwCacheObj();
+
+    const void *GetOwner() const { return m_pOwner; }
+    inline bool IsOwner( const void *pNew ) const;
+
+    sal_uInt16 GetCachePos() const { return m_nCachePos; }
+
+    bool IsLocked() const { return 0 != m_nLock; }
+
+#ifdef DBG_UTIL
+    void Lock();
+    void Unlock();
+#else
+    void Lock() { ++m_nLock; }
+    void Unlock() { --m_nLock; }
+#endif
+};
+
+/**
+ * Access class for the Cache
+ *
+ * The Cache object is created in the ctor.
+ * If the Cache does not return one, the member is set to 0 and one is
+ * created on the Get() and added to the Cache (if possible).
+ * Cache users must derive a class from SwCacheAccess in order to
+ * guarantee type safety. The base class should always be called for the
+ * Get(). A derived Get() should only ever guarantee type safety.
+ * Cache objects are always locked for the instance's life time.
+ */
+class SwCacheAccess
+{
+    SwCache &m_rCache;
+
+    void Get_(bool isDuplicateOwnerAllowed);
+
+protected:
+    SwCacheObj *m_pObj;
+    const void *m_pOwner; /// Can be use in NewObj
+
+    virtual SwCacheObj *NewObj() = 0;
+
+    inline SwCacheObj *Get(bool isDuplicateOwnerAllowed);
+
+    inline SwCacheAccess( SwCache &rCache, const void *pOwner, bool bSeek );
+    inline SwCacheAccess( SwCache &rCache, const void* nCacheId, const sal_uInt16 nIndex );
+
+public:
+    virtual ~SwCacheAccess();
+};
+
+
+inline bool SwCacheObj::IsOwner( const void *pNew ) const
+{
+    return m_pOwner && m_pOwner == pNew;
+}
+
+inline SwCacheObj *SwCache::Next( SwCacheObj *pCacheObj)
+{
+    if ( pCacheObj )
+        return pCacheObj->GetNext();
+    else
+        return nullptr;
+}
+
+inline SwCacheAccess::SwCacheAccess( SwCache &rC, const void *pOwn, bool bSeek ) :
+    m_rCache( rC ),
+    m_pObj( nullptr ),
+    m_pOwner( pOwn )
+{
+    if ( bSeek && m_pOwner )
+    {
+        m_pObj = m_rCache.Get( m_pOwner );
+        if (m_pObj)
+            m_pObj->Lock();
+    }
+}
+
+inline SwCacheAccess::SwCacheAccess( SwCache &rC, const void* nCacheId,
+                              const sal_uInt16 nIndex ) :
+    m_rCache( rC ),
+    m_pObj( nullptr ),
+    m_pOwner( nCacheId )
+{
+    if ( m_pOwner )
+    {
+        m_pObj = m_rCache.Get( m_pOwner, nIndex );
+        if (m_pObj)
+            m_pObj->Lock();
+    }
+}
+
+inline SwCacheObj *SwCacheAccess::Get(bool const isDuplicateOwnerAllowed = true)
+{
+    if ( !m_pObj )
+        Get_(isDuplicateOwnerAllowed);
+    return m_pObj;
+}
+
+#endif
+
+/* vim:set shiftwidth=4 softtabstop=4 expandtab: */