Adding upstream version 1:7.0.4.upstream/1%7.0.4upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 209 insertions, 0 deletions

diff --git a/stoc/source/corereflection/lrucache.hxx b/stoc/source/corereflection/lrucache.hxx
new file mode 100644
index 000000000..4ed99eaa7
--- /dev/null
+++ b/stoc/source/corereflection/lrucache.hxx
@@ -0,0 +1,209 @@
+/* -*- 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_STOC_SOURCE_COREREFLECTION_LRUCACHE_HXX
+#define INCLUDED_STOC_SOURCE_COREREFLECTION_LRUCACHE_HXX
+
+// __CACHE_DIAGNOSE forces cache size to 4 and works only for OUString keys
+//  #define __CACHE_DIAGNOSE 1
+
+#include <osl/mutex.hxx>
+#include <rtl/ustring.hxx>
+
+#include <memory>
+#include <unordered_map>
+
+namespace com::sun::star::uno { class Any; }
+
+/** Implementation of a least recently used (lru) cache.
+    <br>
+*/
+template< class t_Key, class t_Val, class t_KeyHash >
+class LRU_Cache
+{
+    struct CacheEntry
+    {
+        t_Key               aKey;
+        t_Val               aVal;
+        CacheEntry *        pPred;
+        CacheEntry *        pSucc;
+    };
+    typedef std::unordered_map< t_Key, CacheEntry *, t_KeyHash > t_Key2Element;
+
+    mutable ::osl::Mutex        _aCacheMutex;
+    sal_Int32                   _nCachedElements;
+    t_Key2Element               _aKey2Element;
+
+    std::unique_ptr<CacheEntry[]> _pBlock;
+    mutable CacheEntry *        _pHead;
+    mutable CacheEntry *        _pTail;
+    inline void toFront( CacheEntry * pEntry ) const;
+
+public:
+    /** Constructor:
+        <br>
+        @param nCachedElements number of elements to be cached; default param set to 128
+    */
+    explicit inline LRU_Cache();
+
+    /** Retrieves a value from the cache. Returns default constructed value,
+        if none was found.
+        <br>
+        @param rKey a key
+        @return value
+    */
+    inline t_Val getValue( const t_Key & rKey ) const;
+    /** Sets a value to be cached for given key.
+        <br>
+        @param rKey a key
+        @param rValue a value
+    */
+    inline void setValue( const t_Key & rKey, const t_Val & rValue );
+    /** Clears the cache, thus releasing all cached elements and keys.
+        <br>
+    */
+    inline void clear();
+};
+
+template< class t_Key, class t_Val, class t_KeyHash >
+inline LRU_Cache< t_Key, t_Val, t_KeyHash >::LRU_Cache()
+#ifdef __CACHE_DIAGNOSE
+    : _nCachedElements( 4 )
+#else
+    : _nCachedElements( 256 )
+#endif
+    , _pBlock( nullptr )
+    , _pHead( nullptr )
+    , _pTail( nullptr )
+{
+    _pBlock.reset(new CacheEntry[_nCachedElements]);
+    _pHead = _pBlock.get();
+    _pTail = _pBlock.get() + _nCachedElements - 1;
+    for (sal_Int32 nPos = _nCachedElements; nPos--;)
+    {
+        _pBlock[nPos].pPred = _pBlock.get() + nPos - 1;
+        _pBlock[nPos].pSucc = _pBlock.get() + nPos + 1;
+    }
+}
+
+template< class t_Key, class t_Val, class t_KeyHash >
+inline void LRU_Cache< t_Key, t_Val, t_KeyHash >::toFront( CacheEntry * pEntry ) const
+{
+    if (pEntry != _pHead)
+    {
+        // cut out element
+        if (pEntry == _pTail)
+        {
+            _pTail = pEntry->pPred;
+        }
+        else
+        {
+            pEntry->pSucc->pPred = pEntry->pPred;
+            pEntry->pPred->pSucc = pEntry->pSucc;
+        }
+        // push to front
+        _pHead->pPred = pEntry;
+        pEntry->pSucc = _pHead;
+        _pHead        = pEntry;
+    }
+}
+
+template< class t_Key, class t_Val, class t_KeyHash >
+inline t_Val LRU_Cache< t_Key, t_Val, t_KeyHash >::getValue( const t_Key & rKey ) const
+{
+    ::osl::MutexGuard aGuard( _aCacheMutex );
+    const typename t_Key2Element::const_iterator iFind( _aKey2Element.find( rKey ) );
+    if (iFind != _aKey2Element.end())
+    {
+        CacheEntry * pEntry = (*iFind).second;
+        toFront( pEntry );
+#ifdef __CACHE_DIAGNOSE
+        SAL_INFO("stoc.corerefl", "> retrieved element \"" );
+        SAL_INFO("stoc.corerefl", "" << pEntry->aKey);
+        SAL_INFO("stoc.corerefl", "\" from cache <" );
+#endif
+        return pEntry->aVal;
+    }
+    return t_Val();
+}
+
+template< class t_Key, class t_Val, class t_KeyHash >
+inline void LRU_Cache< t_Key, t_Val, t_KeyHash >::setValue(
+    const t_Key & rKey, const t_Val & rValue )
+{
+    ::osl::MutexGuard aGuard( _aCacheMutex );
+    if (_nCachedElements > 0)
+    {
+        const typename t_Key2Element::const_iterator iFind( _aKey2Element.find( rKey ) );
+
+        CacheEntry * pEntry;
+        if (iFind == _aKey2Element.end())
+        {
+            pEntry = _pTail; // erase last element
+#ifdef __CACHE_DIAGNOSE
+            if (pEntry->aKey.getLength())
+            {
+                SAL_INFO("stoc.corerefl", "> kicking element \"" );
+                SAL_INFO("stoc.corerefl", "" << pEntry->aKey);
+                SAL_INFO("stoc.corerefl", "\" from cache <" );
+            }
+#endif
+            _aKey2Element.erase( pEntry->aKey );
+            pEntry->aKey = rKey;
+            _aKey2Element[ rKey ] = pEntry;
+        }
+        else
+        {
+            pEntry = (*iFind).second;
+#ifdef __CACHE_DIAGNOSE
+            SAL_INFO("stoc.corerefl", "> replacing element \"" );
+            SAL_INFO("stoc.corerefl", "" << pEntry->aKey);
+            SAL_INFO("stoc.corerefl", "\" in cache <" );
+#endif
+        }
+        pEntry->aVal = rValue;
+        toFront( pEntry );
+    }
+}
+
+template< class t_Key, class t_Val, class t_KeyHash >
+inline void LRU_Cache< t_Key, t_Val, t_KeyHash >::clear()
+{
+    ::osl::MutexGuard aGuard( _aCacheMutex );
+    _aKey2Element.clear();
+    for ( sal_Int32 nPos = _nCachedElements; nPos--; )
+    {
+        _pBlock[nPos].aKey = t_Key();
+        _pBlock[nPos].aVal = t_Val();
+    }
+    _nCachedElements = 0;
+#ifdef __CACHE_DIAGNOSE
+    SAL_INFO("stoc.corerefl", "> cleared cache <" );
+#endif
+}
+
+
+/** Template instance for OUString keys, Any values.<br>
+*/
+typedef LRU_Cache< OUString, css::uno::Any, OUStringHash >
+    LRU_CacheAnyByOUString;
+
+
+#endif
+
+/* vim:set shiftwidth=4 softtabstop=4 expandtab: */