BTreeReader.h

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/*
// $Id: //open/dev/fennel/btree/BTreeReader.h#19 $
// 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_BTreeReader_Included
#define Fennel_BTreeReader_Included

#include "fennel/btree/BTreeAccessBase.h"
#include "fennel/btree/BTreeNode.h"
#include "fennel/tuple/TupleData.h"

FENNEL_BEGIN_NAMESPACE

class FENNEL_BTREE_EXPORT BTreeReader
    : public BTreeAccessBase
{
protected:
    enum ReadMode {
        READ_ALL,
        READ_NONLEAF_ONLY,
        READ_LEAF_ONLY
    };

    class NullPageStack
    {
    public:
        void push_back(PageId)
        {
        }
    };

    inline void accessLeafTuple();

    BTreePageLock pageLock;

    PageId pageId;

    uint iTupleOnLowestLevel;

    bool singular;

    LockMode rootLockMode;

    LockMode nonLeafLockMode;

    LockMode leafLockMode;

    TupleData comparisonKeyData;

    TupleData const *pSearchKey;

    TupleData searchKeyData;

    inline uint binarySearch(
        BTreeNode const &node, DuplicateSeek dupSeek, bool leastUpper,
        bool &found);

    inline TupleData const &getSearchKey();

    inline bool adjustRootLockMode(LockMode &lockMode);

    inline int compareFirstKey(BTreeNode const &node);

    inline void accessTupleInline(BTreeNode const &node, uint iEntry);

    template <bool leafLockCoupling,class PageStack>
    inline bool searchForKeyTemplate(
        TupleData const &key, DuplicateSeek dupSeek, bool leastUpper,
        PageStack &pageStack, PageId startPageId, LockMode initialLockMode,
        ReadMode readMode);

    bool searchForKeyInternal(
        TupleData const &key, DuplicateSeek dupSeek, bool leastUpper,
        PageId startPageId, LockMode initialLockMode,
        ReadMode readMode);

    virtual bool searchExtreme(bool first);

    bool searchExtremeInternal(bool first, ReadMode readMode);

    bool searchNextInternal();

public:
    explicit BTreeReader(BTreeDescriptor const &descriptor);
    virtual ~BTreeReader();

    TupleAccessor const &getTupleAccessorForRead() const;

    inline TupleData &getSearchKeyForWrite();

    inline bool searchFirst();

    inline bool searchLast();

    virtual bool searchForKey(
        TupleData const &key,
        DuplicateSeek dupSeek,
        bool leastUpper = true);

    virtual bool searchNext();

    virtual void endSearch();

    inline bool isPositioned() const;

    inline bool isSingular() const;
};

inline TupleData &BTreeReader::getSearchKeyForWrite()
{
    return searchKeyData;
}

inline bool BTreeReader::isSingular() const
{
    return singular;
}

inline bool BTreeReader::isPositioned() const
{
    return pageLock.isLocked();
}

inline bool BTreeReader::searchFirst()
{
    return searchExtreme(true);
}

inline bool BTreeReader::searchLast()
{
    return searchExtreme(false);
}

FENNEL_END_NAMESPACE

#endif

// End BTreeReader.h

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