libreoffice/sd/source/ui/slidesorter/cache/SlsPageCacheManager.cxx

/*************************************************************************
 *
 *  $RCSfile: SlsPageCacheManager.cxx,v $
 *
 *  $Revision: 1.4 $
 *
 *  last change: $Author: rt $ $Date: 2005-11-10 15:47:45 $
 *
 *  The Contents of this file are made available subject to the terms of
 *  either of the following licenses
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 *         - GNU Lesser General Public License Version 2.1
 *         - Sun Industry Standards Source License Version 1.1
 *
 *  Sun Microsystems Inc., October, 2000
 *
 *  GNU Lesser General Public License Version 2.1
 *  =============================================
 *  Copyright 2000 by Sun Microsystems, Inc.
 *  901 San Antonio Road, Palo Alto, CA 94303, USA
 *
 *  This library is free software; you can redistribute it and/or
 *  modify it under the terms of the GNU Lesser General Public
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 *
 *
 *  Sun Industry Standards Source License Version 1.1
 *  =================================================
 *  The contents of this file are subject to the Sun Industry Standards
 *  Source License Version 1.1 (the "License"); You may not use this file
 *  except in compliance with the License. You may obtain a copy of the
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 ************************************************************************/

#include "cache/SlsPageCacheManager.hxx"

#include "SlsBitmapCache.hxx"
#include "view/SlideSorterView.hxx"
#include "model/SlideSorterModel.hxx"

#include <deque>
#include <map>
#include <boost/weak_ptr.hpp>

namespace {

/** Collection of data that is stored for all active preview caches.
*/
class CacheDescriptor
{
public:
    SdDrawDocument* mpDocument;
    Size maPreviewSize;

    CacheDescriptor(SdDrawDocument* pDocument, const Size& rPreviewSize)
        :mpDocument(pDocument),maPreviewSize(rPreviewSize)
    {}
    /// Test for equality with respect to all members.
    class Equal {public: bool operator() (
        const CacheDescriptor& rDescriptor1, const CacheDescriptor& rDescriptor2) const {
        return rDescriptor1.mpDocument==rDescriptor2.mpDocument
            && rDescriptor1.maPreviewSize==rDescriptor2.maPreviewSize;
    } };
    /// Hash function that takes all members into account.
    class Hash {public: size_t operator() (const CacheDescriptor& rDescriptor) const {
        return (size_t)rDescriptor.mpDocument + rDescriptor.maPreviewSize.Width();
    } };
};




/** Collection of data that is stored for the inactive, recently used
    caches.
*/
class RecentlyUsedCacheDescriptor
{
public:
    SdDrawDocument* mpDocument;
    Size maPreviewSize;
    ::boost::shared_ptr< ::sd::slidesorter::cache::PageCacheManager::Cache> mpCache;

    RecentlyUsedCacheDescriptor(
        SdDrawDocument* pDocument,
        const Size& rPreviewSize,
        const ::boost::shared_ptr< ::sd::slidesorter::cache::PageCacheManager::Cache>& rpCache)
        :mpDocument(pDocument),maPreviewSize(rPreviewSize),mpCache(rpCache)
    {}
};




/** The list of recently used caches is organized as queue.  When elements
    are added the list is shortened to the maximally allowed number of
    elements by removing the least recently used elements.
*/
typedef ::std::deque<RecentlyUsedCacheDescriptor> RecentlyUsedQueue;




/** Compare the caches by preview size.  Those that match the given size
    come first, then, regardless of the given size, the largest ones before
    the smaller ones.
*/
class BestFittingCacheComparer
{
public:
    BestFittingCacheComparer (const Size& rPreferredSize)
        : maPreferredSize(rPreferredSize)
    {}
    bool operator()(const ::sd::slidesorter::cache::PageCacheManager::BestFittingPageCaches::value_type& rElement1,
        const ::sd::slidesorter::cache::PageCacheManager::BestFittingPageCaches::value_type& rElement2)
    {
        if (rElement1.first == maPreferredSize)
            return true;
        else if (rElement2.first == maPreferredSize)
            return false;
        else
            return (rElement1.first.Width()*rElement1.first.Height()
                > rElement2.first.Width()*rElement2.first.Height());
    }

private:
    Size maPreferredSize;
};

} // end of anonymous namespace


namespace sd { namespace slidesorter { namespace cache {

/** Container for the active caches.
*/
class PageCacheManager::PageCacheContainer
    : public ::std::hash_map<CacheDescriptor,
                             ::boost::shared_ptr<PageCacheManager::Cache>,
                             CacheDescriptor::Hash,
                             CacheDescriptor::Equal>
{
public:
    PageCacheContainer (void) {}

    /** Compare entries in the cache container with respect to the cache
        address only.
    */
    class CompareWithCache { public:
        CompareWithCache(const ::boost::shared_ptr<PageCacheManager::Cache>& rpCache)
            : mpCache(rpCache) {}
        bool operator () (const PageCacheContainer::value_type& rValue)
        { return rValue.second == mpCache; }
    private:
        ::boost::shared_ptr<PageCacheManager::Cache> mpCache;
    };
};


/** The recently used caches are stored in one queue for each document.
*/
class PageCacheManager::RecentlyUsedPageCaches
    : public ::std::map<SdDrawDocument*,RecentlyUsedQueue>
{
public:
    RecentlyUsedPageCaches (void) {};
};




//===== PageCacheManager ====================================================

::boost::weak_ptr<PageCacheManager> PageCacheManager::mpInstance;

::boost::shared_ptr<PageCacheManager> PageCacheManager::Instance (void)
{
    ::boost::shared_ptr<PageCacheManager> pInstance;

    ::osl::MutexGuard aGuard (::osl::Mutex::getGlobalMutex());

    pInstance = mpInstance.lock();
    if (pInstance.get() == NULL)
    {
        pInstance.reset(new PageCacheManager());
        mpInstance = pInstance;
    }

    return pInstance;
}




PageCacheManager::PageCacheManager (void)
    : mpPageCaches(new PageCacheContainer()),
      mpRecentlyUsedPageCaches(new RecentlyUsedPageCaches()),
      mnMaximalRecentlyCacheCount(2)
{
}




PageCacheManager::~PageCacheManager (void)
{
}




::boost::shared_ptr<PageCacheManager::Cache> PageCacheManager::GetCache (
    SdDrawDocument* pDocument,
    const Size& rPreviewSize)
{
    ::boost::shared_ptr<Cache> pResult;

    // Look for the cache in the list of active caches.
    CacheDescriptor aKey (pDocument, rPreviewSize);
    PageCacheContainer::iterator iCache (mpPageCaches->find(aKey));
    if (iCache != mpPageCaches->end())
        pResult = iCache->second;

    // Look for the cache in the list of recently used caches.
    if (pResult.get() == NULL)
        pResult = GetRecentlyUsedCache(pDocument, rPreviewSize);

    // Create the cache when no suitable one does exist.
    if (pResult.get() == NULL)
        pResult.reset(new Cache());

    // The cache may be newly created and thus empty or is old and may
    // contain previews that are not up-to-date.  Recycle previews from
    // other caches to fill in the holes.
    Recycle(pResult, pDocument,rPreviewSize);

    // Put the new (or old) cache into the container.
    if (pResult.get() != NULL)
        mpPageCaches->insert(PageCacheContainer::value_type(aKey, pResult));

    OSL_TRACE("returning cache %x for document %x and size %d %d",
        pResult.get(), pDocument, rPreviewSize.Width(),rPreviewSize.Height());

    return pResult;
}




void PageCacheManager::Recycle (
    const ::boost::shared_ptr<Cache>& rpCache,
    SdDrawDocument* pDocument,
    const Size& rPreviewSize)
{
    BestFittingPageCaches aCaches;

    // Add bitmap caches from active caches.
    PageCacheContainer::iterator iActiveCache;
    for (iActiveCache=mpPageCaches->begin(); iActiveCache!=mpPageCaches->end(); ++iActiveCache)
    {
        if (iActiveCache->first.mpDocument == pDocument)
            aCaches.push_back(BestFittingPageCaches::value_type(
                iActiveCache->first.maPreviewSize, iActiveCache->second));
    }

    // Add bitmap caches from recently used caches.
    RecentlyUsedPageCaches::iterator iQueue (mpRecentlyUsedPageCaches->find(pDocument));
    if (iQueue != mpRecentlyUsedPageCaches->end())
    {
        RecentlyUsedQueue::const_iterator iRecentCache;
        for (iRecentCache=iQueue->second.begin();iRecentCache!=iQueue->second.end();++iRecentCache)
            aCaches.push_back(BestFittingPageCaches::value_type(
                iRecentCache->maPreviewSize, iRecentCache->mpCache));
    }

    ::std::sort(aCaches.begin(), aCaches.end(), BestFittingCacheComparer(rPreviewSize));

    BestFittingPageCaches::const_iterator iBestCache;
    for (iBestCache=aCaches.begin(); iBestCache!=aCaches.end(); ++iBestCache)
    {
        rpCache->Recycle(*iBestCache->second);
    }
}




void PageCacheManager::ReleaseCache (const ::boost::shared_ptr<Cache>& rpCache)
{
    PageCacheContainer::iterator iCache (::std::find_if(
        mpPageCaches->begin(),
        mpPageCaches->end(),
        PageCacheContainer::CompareWithCache(rpCache)));

    if (iCache != mpPageCaches->end())
    {
        OSL_ASSERT(iCache->second == rpCache);

        PutRecentlyUsedCache(iCache->first.mpDocument,iCache->first.maPreviewSize,rpCache);

        mpPageCaches->erase(iCache);
    }
}




::boost::shared_ptr<PageCacheManager::Cache> PageCacheManager::ChangeSize (
    const ::boost::shared_ptr<Cache>& rpCache,
    const Size& rOldPreviewSize,
    const Size& rNewPreviewSize)
{
    OSL_TRACE("changing size of cache %x from %d %d to %d %d",
        rpCache.get(),
        rOldPreviewSize.Width(),rOldPreviewSize.Height(),
        rNewPreviewSize.Width(),rNewPreviewSize.Height());
    ::boost::shared_ptr<Cache> pResult;

    if (rpCache.get() != NULL)
    {
        // Look up the given cache in the list of active caches.
        PageCacheContainer::iterator iCacheToChange (::std::find_if(
            mpPageCaches->begin(),
            mpPageCaches->end(),
            PageCacheContainer::CompareWithCache(rpCache)));
        OSL_ASSERT(iCacheToChange != mpPageCaches->end());
        if (iCacheToChange != mpPageCaches->end())
        {
            OSL_ASSERT(iCacheToChange->second == rpCache);

            // Now, we can change the preview size of the existing one by
            // removing the cache from the list and re-insert it with the
            // updated size.
            mpPageCaches->erase(iCacheToChange);
            mpPageCaches->insert(PageCacheContainer::value_type(
                CacheDescriptor(iCacheToChange->first.mpDocument,rNewPreviewSize),
                rpCache));

            pResult = rpCache;
        }
    }

    return pResult;
}




void PageCacheManager::InvalidatePreviewBitmap (
    SdDrawDocument* pDocument,
    const SdrPage* pKey)
{
    if (pDocument!=NULL)
    {
        // Iterate over all caches that are currently in use and invalidate
        // the previews in those that belong to the document.
        PageCacheContainer::iterator iCache;
        for (iCache=mpPageCaches->begin(); iCache!=mpPageCaches->end();  ++iCache)
            if (iCache->first.mpDocument == pDocument)
                iCache->second->InvalidateBitmap(pKey);

        // Invalidate the previews in the recently used caches belonging to
        // the given document.
        RecentlyUsedPageCaches::iterator iQueue (mpRecentlyUsedPageCaches->find(pDocument));
        if (iQueue != mpRecentlyUsedPageCaches->end())
        {
            RecentlyUsedQueue::const_iterator iCache;
            for (iCache=iQueue->second.begin(); iCache!=iQueue->second.end(); ++iCache)
                iCache->mpCache->InvalidateBitmap(pKey);
        }
    }
}




::boost::shared_ptr<PageCacheManager::Cache> PageCacheManager::GetRecentlyUsedCache (
    SdDrawDocument* pDocument,
    const Size& rPreviewSize)
{
    ::boost::shared_ptr<Cache> pCache;

    // Look for the cache in the list of recently used caches.
    RecentlyUsedPageCaches::iterator iQueue (mpRecentlyUsedPageCaches->find(pDocument));
    if (iQueue != mpRecentlyUsedPageCaches->end())
    {
        RecentlyUsedQueue::iterator iCache;
        for (iCache=iQueue->second.begin(); iCache!= iQueue->second.end(); ++iCache)
            if (iCache->maPreviewSize == rPreviewSize)
            {
                pCache = iCache->mpCache;
                iQueue->second.erase(iCache);
                break;
            }
    }

    return pCache;
}




void PageCacheManager::PutRecentlyUsedCache(
    SdDrawDocument* pDocument,
    const Size& rPreviewSize,
    const ::boost::shared_ptr<Cache>& rpCache)
{
    // Look up the list of recently used caches for the given document.
    RecentlyUsedPageCaches::iterator iQueue (mpRecentlyUsedPageCaches->find(pDocument));
    if (iQueue == mpRecentlyUsedPageCaches->end())
        iQueue = mpRecentlyUsedPageCaches->insert(
            RecentlyUsedPageCaches::value_type(pDocument, RecentlyUsedQueue())
            ).first;

    if (iQueue != mpRecentlyUsedPageCaches->end())
    {
        iQueue->second.push_front(RecentlyUsedCacheDescriptor(pDocument,rPreviewSize,rpCache));
        // Shorten the list of recently used caches to the allowed maximal length.
        while (iQueue->second.size() > mnMaximalRecentlyCacheCount)
            iQueue->second.pop_back();
    }
}



} } } // end of namespace ::sd::slidesorter::cache