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/****************************************************************************
**
** Copyright (C) 2012 Digia Plc and/or its subsidiary(-ies).
** Contact: http://www.qt-project.org/legal
**
** This file is part of the QtAddOn.JsonDb module of the Qt Toolkit.
**
** $QT_BEGIN_LICENSE:LGPL$
** Commercial License Usage
** Licensees holding valid commercial Qt licenses may use this file in
** accordance with the commercial license agreement provided with the
** Software or, alternatively, in accordance with the terms contained in
** a written agreement between you and Digia. For licensing terms and
** conditions see http://qt.digia.com/licensing. For further information
** use the contact form at http://qt.digia.com/contact-us.
**
** GNU Lesser General Public License Usage
** Alternatively, this file may be used under the terms of the GNU Lesser
** General Public License version 2.1 as published by the Free Software
** Foundation and appearing in the file LICENSE.LGPL included in the
** packaging of this file. Please review the following information to
** ensure the GNU Lesser General Public License version 2.1 requirements
** will be met: http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html.
**
** In addition, as a special exception, Digia gives you certain additional
** rights. These rights are described in the Digia Qt LGPL Exception
** version 1.1, included in the file LGPL_EXCEPTION.txt in this package.
**
** GNU General Public License Usage
** Alternatively, this file may be used under the terms of the GNU
** General Public License version 3.0 as published by the Free Software
** Foundation and appearing in the file LICENSE.GPL included in the
** packaging of this file. Please review the following information to
** ensure the GNU General Public License version 3.0 requirements will be
** met: http://www.gnu.org/copyleft/gpl.html.
**
**
** $QT_END_LICENSE$
**
****************************************************************************/
#ifndef QBTREE_H
#define QBTREE_H
#include <QByteArray>
#include <QString>
#include <QList>
#include <QtEndian>
class QBtreeTxn;
class QBtreeCursor;
struct btree;
struct btree_stat;
class QBtree
{
public:
enum DbFlag {
Default=0x0000,
ReverseKeys=0x001,
NoSync=0x004,
ReadOnly=0x008,
UseSyncMarker=0x010,
NoPageChecksums=0x020
};
Q_DECLARE_FLAGS(DbFlags, DbFlag)
static quint32 readWriteFlags()
{ return (quint32)(QBtree::NoSync | QBtree::UseSyncMarker); }
class Stat
{
public:
qint32 reads;
qint32 hits;
qint32 writes;
quint32 psize;
quint32 ksize;
Stat() : reads(0), hits(0), writes(0), psize(0), ksize(0) {};
Stat &operator += (const Stat &o)
{
reads += o.reads;
hits += o.hits;
writes += o.writes;
psize = o.psize;
ksize = o.ksize;
return *this;
}
};
typedef QBtreeCursor CursorType;
typedef QBtreeTxn TransactionType;
typedef Stat StatType;
QBtree();
QBtree(const QString &filename);
~QBtree();
typedef int (*CompareFunction)(const QByteArray &, const QByteArray &);
void setCompareFunction(CompareFunction cmp);
void setFileName(const QString &filename);
void setFlags(DbFlags flags);
void setAutoCompactRate(int rate);
void setCacheSize(unsigned int cacheSize);
int autoCompactRate() const
{ return mAutoCompactRate; }
bool open();
void close();
bool isOpen() const;
bool open(quint32 flags)
{ setFlags(QFlag(flags)); return open(); }
enum TxnFlag { TxnReadWrite, TxnReadOnly };
QBtreeTxn *begin(TxnFlag flag = TxnReadWrite);
QBtreeTxn *beginWrite()
{ return begin(QBtree::TxnReadWrite); }
QBtreeTxn *beginRead()
{ return begin(QBtree::TxnReadOnly); }
QBtreeTxn *beginRead(quint32 tag);
bool rollback();
QString fileName() const { return mFilename; }
QBtree::Stat stats() const;
quint64 count() const;
btree *handle() const { return mBtree; }
quint32 tag() const;
bool compact();
bool sync();
void dump() const;
bool isWriting() const;
QBtreeTxn *writeTransaction();
QString errorMessage();
private:
bool commit(QBtreeTxn *txn, quint32 tag);
void abort(QBtreeTxn *txn);
friend class QBtreeTxn;
QString mFilename;
btree *mBtree;
CompareFunction mCmp;
int mCacheSize;
int mFlags;
qint32 mWrites, mReads, mHits; // pages written and read, page cache hits
int mCommitCount;
int mAutoCompactRate;
QBtreeTxn *mWriteTxn;
Q_DISABLE_COPY(QBtree)
};
Q_DECLARE_OPERATORS_FOR_FLAGS(QBtree::DbFlags)
#endif // QBTREE_H
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