Segment.h

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/*
// $Id: //open/dev/fennel/segment/Segment.h#18 $
// Fennel is a library of data storage and processing components.
// Copyright (C) 2005-2009 The Eigenbase Project
// Copyright (C) 2005-2009 SQLstream, Inc.
// Copyright (C) 2005-2009 LucidEra, Inc.
// Portions Copyright (C) 1999-2009 John V. Sichi
//
// This program is free software; you can redistribute it and/or modify it
// under the terms of the GNU General Public License as published by the Free
// Software Foundation; either version 2 of the License, or (at your option)
// any later version approved by The Eigenbase Project.
//
// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU General Public License for more details.
//
// You should have received a copy of the GNU General Public License
// along with this program; if not, write to the Free Software
// Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
*/

#ifndef Fennel_Segment_Included
#define Fennel_Segment_Included

#include "fennel/cache/MappedPageListener.h"
#include "fennel/common/CompoundId.h"
#include "fennel/common/ClosableObject.h"

#include <boost/enable_shared_from_this.hpp>
#include <boost/utility.hpp>
#include <hash_map>

FENNEL_BEGIN_NAMESPACE

class FENNEL_SEGMENT_EXPORT Segment
    : public MappedPageListener,
        public boost::noncopyable,
        public ClosableObject,
        public boost::enable_shared_from_this<Segment>
{
    uint cbUsablePerPage;

protected:

    typedef std::hash_map<PageId,PageId> PageMap;
    typedef PageMap::const_iterator PageMapConstIter;

    SharedCache pCache;

    WeakSegment pTracingSegment;

    explicit Segment(SharedCache);
    void setUsablePageSize(uint);
    PConstBuffer getReadableFooter(CachePage &page);
    PBuffer getWritableFooter(CachePage &page);

    // helper methods for LINEAR_ALLOCATION segments
    PageId getLinearPageSuccessor(PageId pageId);

    void setLinearPageSuccessor(PageId pageId,PageId successorId);

    bool isLinearPageIdAllocated(PageId pageId);

    // implement ClosableObject
    virtual void closeImpl();

public:

    enum AllocationOrder {
        RANDOM_ALLOCATION,

        ASCENDING_ALLOCATION,

        CONSECUTIVE_ALLOCATION,

        LINEAR_ALLOCATION
    };

    virtual ~Segment();

    inline SharedCache getCache() const;

    uint getFullPageSize() const;

    inline uint getUsablePageSize() const;

    virtual void initForUse();

    virtual BlockNum getAllocatedSizeInPages() = 0;

    virtual BlockNum getNumPagesOccupiedHighWater() = 0;

    virtual BlockNum getNumPagesExtended() = 0;

    SharedSegment getTracingSegment();

    void setTracingSegment(WeakSegment pTracingSegmentInit);

    void checkpoint(
        CheckpointType checkpointType = CHECKPOINT_FLUSH_ALL);

    virtual void delegatedCheckpoint(
        Segment &delegatingSegment,
        CheckpointType checkpointType);

    virtual PageId getPageSuccessor(PageId pageId) = 0;

    virtual void setPageSuccessor(PageId pageId, PageId successorId) = 0;

    virtual AllocationOrder getAllocationOrder() const = 0;

    virtual BlockId translatePageId(PageId) = 0;

    virtual PageId translateBlockId(BlockId) = 0;

    virtual PageId allocatePageId(PageOwnerId ownerId = ANON_PAGE_OWNER_ID) = 0;

    virtual bool ensureAllocatedSize(BlockNum nPages);

    virtual void deallocatePageRange(
        PageId startPageId,
        PageId endPageId) = 0;

    virtual bool isPageIdAllocated(PageId pageId) = 0;

    virtual PageId updatePage(PageId pageId, bool needsTranslation = false);

    virtual MappedPageListener *getMappedPageListener(BlockId blockId);

    virtual bool isWriteVersioned();

    static PageId getLinearPageId(BlockNum iPage);

    static BlockNum getLinearBlockNum(PageId pageId);

    // implement MappedPageListener
    virtual MappedPageListener *getTracingListener();
};

inline PageId Segment::getLinearPageId(BlockNum iPage)
{
    return PageId(iPage);
}

inline BlockNum Segment::getLinearBlockNum(PageId pageId)
{
    return opaqueToInt(pageId);
}

inline SharedCache Segment::getCache() const
{
    return pCache;
}

inline uint Segment::getUsablePageSize() const
{
    return cbUsablePerPage;
}

FENNEL_END_NAMESPACE

#endif

// End Segment.h

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