1 files changed, 426 insertions, 0 deletions
diff --git a/store/source/storcach.cxx b/store/source/storcach.cxx
new file mode 100644
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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 .
+ */
+
+#include <sal/config.h>
+
+#include "storcach.hxx"
+
+#include <sal/log.hxx>
+#include <sal/types.h>
+#include <sal/macros.h>
+#include <rtl/alloc.h>
+#include <osl/diagnose.h>
+
+#include <store/types.h>
+#include "storbase.hxx"
+
+#include <memory>
+#include <string.h>
+
+using namespace store;
+
+// Entry
+
+namespace store {
+struct Entry
+{
+    // Representation
+    std::shared_ptr<PageData> m_xPage;
+    sal_uInt32 m_nOffset;
+    Entry *    m_pNext;
+
+    // Allocation
+    static void * operator new (size_t, void * p) { return p; }
+    static void   operator delete (void *, void *) {}
+
+    // Construction
+    explicit Entry (std::shared_ptr<PageData> const & rxPage, sal_uInt32 nOffset)
+        : m_xPage(rxPage), m_nOffset(nOffset), m_pNext(nullptr)
+    {}
+};
+};
+
+// EntryCache interface
+namespace
+{
+
+class EntryCache
+{
+    rtl_cache_type * m_entry_cache;
+
+public:
+    static EntryCache & get();
+
+    Entry * create (std::shared_ptr<PageData> const & rxPage, sal_uInt32 nOffset);
+
+    void destroy (Entry * entry);
+
+protected:
+    EntryCache();
+    ~EntryCache();
+};
+
+} // namespace
+
+// EntryCache implementation
+EntryCache & EntryCache::get()
+{
+    static EntryCache g_entry_cache;
+    return g_entry_cache;
+}
+
+EntryCache::EntryCache()
+{
+    m_entry_cache = rtl_cache_create (
+        "store_cache_entry_cache",
+        sizeof(Entry),
+        0, // objalign
+        nullptr, // constructor
+        nullptr, // destructor
+        nullptr, // reclaim
+        nullptr, // userarg
+        nullptr, // default source
+        0  // flags
+        );
+}
+
+EntryCache::~EntryCache()
+{
+    rtl_cache_destroy (m_entry_cache);
+    m_entry_cache = nullptr;
+}
+
+Entry * EntryCache::create (std::shared_ptr<PageData> const & rxPage, sal_uInt32 nOffset)
+{
+    void * pAddr = rtl_cache_alloc (m_entry_cache);
+    if (pAddr != nullptr)
+    {
+        // construct
+        return new(pAddr) Entry (rxPage, nOffset);
+    }
+    return nullptr;
+}
+
+void EntryCache::destroy (Entry * entry)
+{
+    if (entry != nullptr)
+    {
+        // destruct
+        entry->~Entry();
+
+        // return to cache
+        rtl_cache_free (m_entry_cache, entry);
+    }
+}
+
+// highbit():= log2() + 1 (complexity O(1))
+static int highbit(std::size_t n)
+{
+    int k = 1;
+
+    if (n == 0)
+        return 0;
+#if SAL_TYPES_SIZEOFLONG == 8
+    if (n & 0xffffffff00000000ul)
+    {
+        k |= 32;
+        n >>= 32;
+    }
+#endif
+    if (n & 0xffff0000)
+    {
+        k |= 16;
+        n >>= 16;
+    }
+    if (n & 0xff00)
+    {
+        k |= 8;
+        n >>= 8;
+    }
+    if (n & 0xf0)
+    {
+        k |= 4;
+        n >>= 4;
+    }
+    if (n & 0x0c)
+    {
+        k |= 2;
+        n >>= 2;
+    }
+    if (n & 0x02)
+        k++;
+
+    return k;
+}
+
+
+PageCache::PageCache (sal_uInt16 nPageSize)
+    : m_hash_table   (m_hash_table_0),
+      m_hash_size    (theTableSize),
+      m_hash_shift   (highbit(m_hash_size) - 1),
+      m_page_shift   (highbit(nPageSize) - 1),
+      m_hash_entries (0),
+      m_nHit         (0),
+      m_nMissed      (0)
+{
+    static size_t const theSize = SAL_N_ELEMENTS(m_hash_table_0);
+    static_assert(theSize == theTableSize, "must be equal");
+}
+
+PageCache::~PageCache()
+{
+    double s_x = 0.0;
+    std::size_t i, n = m_hash_size;
+    for (i = 0; i < n; i++)
+    {
+        int x = 0;
+        Entry * entry = m_hash_table[i];
+        while (entry != nullptr)
+        {
+            m_hash_table[i] = entry->m_pNext;
+            entry->m_pNext = nullptr;
+            EntryCache::get().destroy (entry);
+            entry = m_hash_table[i];
+            x += 1;
+        }
+        s_x  += double(x);
+    }
+    double ave = s_x / double(n);
+    SAL_INFO("store", "avg hash chain length: " << ave);
+
+    if (m_hash_table != m_hash_table_0)
+    {
+        std::free (m_hash_table);
+        m_hash_table = m_hash_table_0;
+        m_hash_size  = theTableSize;
+        m_hash_shift = highbit(m_hash_size) - 1;
+    }
+    SAL_INFO("store", "Hits: " << m_nHit << ", Misses: " <<  m_nMissed);
+}
+
+void PageCache::rescale_Impl (std::size_t new_size)
+{
+    std::size_t new_bytes = new_size * sizeof(Entry*);
+    Entry ** new_table = static_cast<Entry**>(std::malloc(new_bytes));
+
+    if (new_table == nullptr)
+        return;
+
+    Entry ** old_table = m_hash_table;
+    std::size_t old_size  = m_hash_size;
+
+    SAL_INFO(
+        "store",
+        "ave chain length: " << (m_hash_entries >> m_hash_shift)
+            << ", total entries: " << m_hash_entries << " [old_size: "
+            << old_size << " new_size: " << new_size << "]");
+
+    memset (new_table, 0, new_bytes);
+
+    m_hash_table = new_table;
+    m_hash_size  = new_size;
+    m_hash_shift = highbit(m_hash_size) - 1;
+
+    std::size_t i;
+    for (i = 0; i < old_size; i++)
+    {
+        Entry * curr = old_table[i];
+        while (curr != nullptr)
+        {
+            Entry * next = curr->m_pNext;
+            int index = hash_index_Impl(curr->m_nOffset);
+            curr->m_pNext = m_hash_table[index];
+            m_hash_table[index] = curr;
+            curr = next;
+        }
+        old_table[i] = nullptr;
+    }
+    if (old_table != m_hash_table_0)
+    {
+
+        std::free (old_table);
+    }
+}
+
+Entry * PageCache::lookup_Impl (Entry * entry, sal_uInt32 nOffset)
+{
+    int lookups = 0;
+    while (entry != nullptr)
+    {
+        if (entry->m_nOffset == nOffset)
+            break;
+
+        lookups += 1;
+        entry = entry->m_pNext;
+    }
+    if (lookups > 2)
+    {
+        std::size_t new_size = m_hash_size, ave = m_hash_entries >> m_hash_shift;
+        for (; ave > 4; new_size *= 2, ave /= 2)
+            continue;
+        if (new_size != m_hash_size)
+            rescale_Impl (new_size);
+    }
+    return entry;
+}
+
+storeError PageCache::lookupPageAt (std::shared_ptr<PageData> & rxPage, sal_uInt32 nOffset)
+{
+    OSL_PRECOND(!(nOffset == STORE_PAGE_NULL), "store::PageCache::lookupPageAt(): invalid Offset");
+    if (nOffset == STORE_PAGE_NULL)
+        return store_E_CantSeek;
+
+    int index = hash_index_Impl(nOffset);
+    Entry const * entry = lookup_Impl (m_hash_table[index], nOffset);
+    if (entry != nullptr)
+    {
+        // Existing entry.
+        rxPage = entry->m_xPage;
+
+        // Update stats and leave.
+        m_nHit += 1;
+        return store_E_None;
+    }
+
+    // Cache miss. Update stats and leave.
+    m_nMissed += 1;
+    return store_E_NotExists;
+}
+
+storeError PageCache::insertPageAt (std::shared_ptr<PageData> const & rxPage, sal_uInt32 nOffset)
+{
+    // [SECURITY:ValInput]
+    PageData const * pagedata = rxPage.get();
+    OSL_PRECOND(!(pagedata == nullptr), "store::PageCache::insertPageAt(): invalid Page");
+    if (pagedata == nullptr)
+        return store_E_InvalidParameter;
+
+    sal_uInt32 const offset = pagedata->location();
+    OSL_PRECOND(!(nOffset != offset), "store::PageCache::insertPageAt(): inconsistent Offset");
+    if (nOffset != offset)
+        return store_E_InvalidParameter;
+
+    OSL_PRECOND(!(nOffset == STORE_PAGE_NULL), "store::PageCache::insertPageAt(): invalid Offset");
+    if (nOffset == STORE_PAGE_NULL)
+        return store_E_CantSeek;
+
+    Entry * entry = EntryCache::get().create (rxPage, nOffset);
+    if (entry != nullptr)
+    {
+        // Insert new entry.
+        int index = hash_index_Impl(nOffset);
+        entry->m_pNext = m_hash_table[index];
+        m_hash_table[index] = entry;
+
+        // Update stats and leave.
+        m_hash_entries += 1;
+        return store_E_None;
+    }
+    return store_E_OutOfMemory;
+}
+
+storeError PageCache::updatePageAt (std::shared_ptr<PageData> const & rxPage, sal_uInt32 nOffset)
+{
+    // [SECURITY:ValInput]
+    PageData const * pagedata = rxPage.get();
+    OSL_PRECOND(!(pagedata == nullptr), "store::PageCache::updatePageAt(): invalid Page");
+    if (pagedata == nullptr)
+        return store_E_InvalidParameter;
+
+    sal_uInt32 const offset = pagedata->location();
+    OSL_PRECOND(!(nOffset != offset), "store::PageCache::updatePageAt(): inconsistent Offset");
+    if (nOffset != offset)
+        return store_E_InvalidParameter;
+
+    OSL_PRECOND(!(nOffset == STORE_PAGE_NULL), "store::PageCache::updatePageAt(): invalid Offset");
+    if (nOffset == STORE_PAGE_NULL)
+        return store_E_CantSeek;
+
+    int index = hash_index_Impl(nOffset);
+    Entry *  entry  = lookup_Impl (m_hash_table[index], nOffset);
+    if (entry != nullptr)
+    {
+        // Update existing entry.
+        entry->m_xPage = rxPage;
+
+        // Update stats and leave. // m_nUpdHit += 1;
+        return store_E_None;
+    }
+    return insertPageAt (rxPage, nOffset);
+}
+
+storeError PageCache::removePageAt (sal_uInt32 nOffset)
+{
+    OSL_PRECOND(!(nOffset == STORE_PAGE_NULL), "store::PageCache::removePageAt(): invalid Offset");
+    if (nOffset == STORE_PAGE_NULL)
+        return store_E_CantSeek;
+
+    Entry ** ppEntry = &(m_hash_table[hash_index_Impl(nOffset)]);
+    while (*ppEntry != nullptr)
+    {
+        if ((*ppEntry)->m_nOffset == nOffset)
+        {
+            // Existing entry.
+            Entry * entry = *ppEntry;
+
+            // Dequeue and destroy entry.
+            (*ppEntry) = entry->m_pNext;
+            entry->m_pNext = nullptr;
+            EntryCache::get().destroy (entry);
+
+            // Update stats and leave.
+            m_hash_entries -= 1;
+            return store_E_None;
+        }
+        ppEntry = &((*ppEntry)->m_pNext);
+    }
+    return store_E_NotExists;
+}
+
+/*
+ *
+ * Old OStorePageCache implementation.
+ *
+ * (two-way association (sorted address array, LRU chain)).
+ * (external PageData representation).
+ *
+ */
+
+/*
+ *
+ * PageCache factory implementation.
+ *
+ */
+namespace store {
+
+storeError
+PageCache_createInstance (
+    rtl::Reference< store::PageCache > & rxCache,
+    sal_uInt16                           nPageSize)
+{
+    rxCache = new PageCache (nPageSize);
+    if (!rxCache.is())
+        return store_E_OutOfMemory;
+
+    return store_E_None;
+}
+
+} // namespace store
+
+/* vim:set shiftwidth=4 softtabstop=4 expandtab: */