1 files changed, 276 insertions, 0 deletions
diff --git a/sd/source/ui/slidesorter/cache/SlsRequestQueue.cxx b/sd/source/ui/slidesorter/cache/SlsRequestQueue.cxx
new file mode 100644
index 0000000000..a0dcc9f0cb
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+++ b/sd/source/ui/slidesorter/cache/SlsRequestQueue.cxx
@@ -0,0 +1,276 @@
+/* -*- 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 "SlsRequestQueue.hxx"
+
+#include <sal/log.hxx>
+
+#include <svx/svdpage.hxx>
+
+#include <set>
+#include <utility>
+
+namespace sd::slidesorter::cache {
+
+namespace {
+
+/** This class extends the actual request data with additional information
+    that is used by the priority queues.
+*/
+class Request
+{
+public:
+    Request (
+        CacheKey aKey, sal_Int32 nPriority, RequestPriorityClass eClass)
+        : maKey(aKey), mnPriorityInClass(nPriority), meClass(eClass)
+    {}
+    /** Sort requests according to priority classes and then to priorities.
+    */
+    class Comparator { public:
+        bool operator() (const Request& rRequest1, const Request& rRequest2)
+            const
+        {
+            if (rRequest1.meClass == rRequest2.meClass)
+            {
+                if (rRequest1.mnPriorityInClass == rRequest2.mnPriorityInClass)
+                {
+                    return rRequest1.maKey < rRequest2.maKey;
+                }
+                return rRequest1.mnPriorityInClass > rRequest2.mnPriorityInClass;
+            }
+            return rRequest1.meClass < rRequest2.meClass;
+        }
+    };
+    /** Request data is compared arbitrarily by their addresses in memory.
+        This just establishes an order so that the STL containers are happy.
+        The order is not semantically interpreted.
+    */
+    class DataComparator
+    {
+    public:
+        explicit DataComparator (const CacheKey aKey)
+            : maKey(aKey)
+        {
+        }
+        bool operator() (const Request& rRequest) const
+        {
+            return maKey == rRequest.maKey;
+        }
+    private:
+        const CacheKey maKey;
+    };
+
+    CacheKey maKey;
+    sal_Int32 mnPriorityInClass;
+    RequestPriorityClass meClass;
+};
+
+}
+
+class RequestQueue::Container
+    : public ::std::set<
+        Request,
+        Request::Comparator>
+{
+};
+
+//=====  GenericRequestQueue  =================================================
+
+RequestQueue::RequestQueue (SharedCacheContext pCacheContext)
+    : mpRequestQueue(new Container),
+      mpCacheContext(std::move(pCacheContext)),
+      mnMinimumPriority(0),
+      mnMaximumPriority(1)
+{
+}
+
+RequestQueue::~RequestQueue()
+{
+    Clear();
+}
+
+void RequestQueue::AddRequest (
+    CacheKey aKey,
+    RequestPriorityClass eRequestClass)
+{
+    ::osl::MutexGuard aGuard (maMutex);
+
+    assert(eRequestClass>=MIN_CLASS && eRequestClass<=MAX_CLASS);
+
+    // If the request is already a member of the queue then remove it so
+    // that the following insertion will use the new prioritization.
+#if OSL_DEBUG_LEVEL >=2
+    bool bRemoved =
+#endif
+    RemoveRequest(aKey);
+
+    // The priority of the request inside its priority class is defined by
+    // the page number.  This ensures a strict top-to-bottom, left-to-right
+    // order.
+    sal_Int32 nPriority (mpCacheContext->GetPriority(aKey));
+    Request aRequest (aKey, nPriority, eRequestClass);
+
+    std::pair<Container::iterator,bool> ret = mpRequestQueue->insert(aRequest);
+    bool bInserted = ret.second;
+
+    if (bInserted)
+    {
+        SdrPage *pPage = const_cast<SdrPage*>(aRequest.maKey);
+        pPage->AddPageUser(*this);
+    }
+
+#if OSL_DEBUG_LEVEL >=2
+    SAL_INFO("sd.sls", __func__ << ": " << (bRemoved?"replaced":"added")
+        << " request for page " << ((aKey->GetPageNum()-1)/2)
+        << " with priority class " << static_cast<int>(eRequestClass));
+#endif
+}
+
+void RequestQueue::PageInDestruction(const SdrPage& rPage)
+{
+    //remove any requests pending for this page which is going away now
+    RemoveRequest(&rPage);
+}
+
+#if OSL_DEBUG_LEVEL >=2
+bool
+#else
+void
+#endif
+RequestQueue::RemoveRequest(
+    CacheKey aKey)
+{
+    ::osl::MutexGuard aGuard (maMutex);
+#if OSL_DEBUG_LEVEL >=2
+    bool bIsRemoved = false;
+#endif
+    while(true)
+    {
+        Container::const_iterator aRequestIterator = ::std::find_if (
+            mpRequestQueue->begin(),
+            mpRequestQueue->end(),
+            Request::DataComparator(aKey));
+        if (aRequestIterator != mpRequestQueue->end())
+        {
+            if (aRequestIterator->mnPriorityInClass == mnMinimumPriority+1)
+                mnMinimumPriority++;
+            else if (aRequestIterator->mnPriorityInClass == mnMaximumPriority-1)
+                mnMaximumPriority--;
+
+            SdrPage *pPage = const_cast<SdrPage*>(aRequestIterator->maKey);
+            pPage->RemovePageUser(*this);
+            mpRequestQueue->erase(aRequestIterator);
+#if OSL_DEBUG_LEVEL >=2
+            bIsRemoved = true;
+#endif
+        }
+        else
+            break;
+    }
+#if OSL_DEBUG_LEVEL >=2
+    return bIsRemoved;
+#endif
+
+}
+
+void RequestQueue::ChangeClass (
+    CacheKey aKey,
+    RequestPriorityClass eNewRequestClass)
+{
+    ::osl::MutexGuard aGuard (maMutex);
+
+    assert(eNewRequestClass>=MIN_CLASS && eNewRequestClass<=MAX_CLASS);
+
+    Container::const_iterator iRequest (
+        ::std::find_if (
+            mpRequestQueue->begin(),
+            mpRequestQueue->end(),
+            Request::DataComparator(aKey)));
+    if (iRequest!=mpRequestQueue->end() && iRequest->meClass!=eNewRequestClass)
+    {
+        AddRequest(aKey, eNewRequestClass);
+    }
+}
+
+CacheKey RequestQueue::GetFront()
+{
+    ::osl::MutexGuard aGuard (maMutex);
+
+    if (mpRequestQueue->empty())
+        throw css::uno::RuntimeException("RequestQueue::GetFront(): queue is empty",
+            nullptr);
+
+    return mpRequestQueue->begin()->maKey;
+}
+
+RequestPriorityClass RequestQueue::GetFrontPriorityClass()
+{
+    ::osl::MutexGuard aGuard (maMutex);
+
+    if (mpRequestQueue->empty())
+        throw css::uno::RuntimeException("RequestQueue::GetFrontPriorityClass(): queue is empty",
+            nullptr);
+
+    return mpRequestQueue->begin()->meClass;
+}
+
+void RequestQueue::PopFront()
+{
+    ::osl::MutexGuard aGuard (maMutex);
+
+    if (  mpRequestQueue->empty())
+        return;
+
+    Container::const_iterator aIter(mpRequestQueue->begin());
+    SdrPage *pPage = const_cast<SdrPage*>(aIter->maKey);
+    pPage->RemovePageUser(*this);
+    mpRequestQueue->erase(aIter);
+
+    // Reset the priority counter if possible.
+    if (mpRequestQueue->empty())
+    {
+        mnMinimumPriority = 0;
+        mnMaximumPriority = 1;
+    }
+}
+
+bool RequestQueue::IsEmpty()
+{
+    ::osl::MutexGuard aGuard (maMutex);
+    return mpRequestQueue->empty();
+}
+
+void RequestQueue::Clear()
+{
+    ::osl::MutexGuard aGuard (maMutex);
+
+    for (const auto& rItem : *mpRequestQueue)
+    {
+        SdrPage *pPage = const_cast<SdrPage*>(rItem.maKey);
+        pPage->RemovePageUser(*this);
+    }
+
+    mpRequestQueue->clear();
+    mnMinimumPriority = 0;
+    mnMaximumPriority = 1;
+}
+
+} // end of namespace ::sd::slidesorter::cache
+
+/* vim:set shiftwidth=4 softtabstop=4 expandtab: */