source: psi/trunk/src/eventdb.h@ 9

/*
 * eventdb.h - asynchronous I/O event database
 * Copyright (C) 2001, 2002  Justin Karneges
 *
 * 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.
 *
 * 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 library; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 *
 */

#ifndef EVENTDB_H
#define EVENTDB_H

#include<qobject.h>
#include<qtimer.h>
#include<qfile.h>
#include<qptrlist.h>
#include"psievent.h"


class EDBItem
{
public:
        EDBItem(PsiEvent *, const QString &id, const QString &nextId, const QString &prevId);
        ~EDBItem();

        PsiEvent *event() const;
        const QString & id() const;
        const QString & nextId() const;
        const QString & prevId() const;

private:
        QString v_id, v_prevId, v_nextId;
        PsiEvent *e;
};

class EDBResult : public QPtrList<EDBItem>
{
public:
        EDBResult() {}
};

class EDB;
class EDBHandle : public QObject
{
        Q_OBJECT
public:
        enum { Read, Write };
        EDBHandle(EDB *);
        ~EDBHandle();

        // operations
        void getLatest(const Jid &, int len);
        void getOldest(const Jid &, int len);
        void get(const Jid &jid, const QString &id, int direction, int len);
        void find(const QString &, const Jid &, const QString &id, int direction);
        void append(const Jid &, PsiEvent *);

        bool busy() const;
        const EDBResult *result() const;
        bool writeSuccess() const;
        int lastRequestType() const;

signals:
        void finished();

private:
        class Private;
        Private *d;

        friend class EDB;
        void edb_resultReady(EDBResult *);
        void edb_writeFinished(bool);
        int listeningFor() const;
};

class EDB : public QObject
{
        Q_OBJECT
public:
        enum { Forward, Backward };
        EDB();
        virtual ~EDB()=0;

protected:
        int genUniqueId() const;
        virtual int getLatest(const Jid &, int len)=0;
        virtual int getOldest(const Jid &, int len)=0;
        virtual int get(const Jid &jid, const QString &id, int direction, int len)=0;
        virtual int append(const Jid &, PsiEvent *)=0;
        virtual int find(const QString &, const Jid &, const QString &id, int direction)=0;
        void resultReady(int, EDBResult *);
        void writeFinished(int, bool);

private:
        class Private;
        Private *d;

        friend class EDBHandle;
        void reg(EDBHandle *);
        void unreg(EDBHandle *);

        int op_getLatest(const Jid &, int len);
        int op_getOldest(const Jid &, int len);
        int op_get(const Jid &, const QString &id, int direction, int len);
        int op_find(const QString &, const Jid &, const QString &id, int direction);
        int op_append(const Jid &, PsiEvent *);
};

class EDBFlatFile : public EDB
{
        Q_OBJECT
public:
        EDBFlatFile();
        ~EDBFlatFile();

        int getLatest(const Jid &, int len);
        int getOldest(const Jid &, int len);
        int get(const Jid &jid, const QString &id, int direction, int len);
        int find(const QString &, const Jid &, const QString &id, int direction);
        int append(const Jid &, PsiEvent *);

        class File;

private slots:
        void performRequests();
        void file_timeout();

private:
        class Private;
        Private *d;

        File *findFile(const Jid &) const;
        File *ensureFile(const Jid &);
};

class EDBFlatFile::File : public QObject
{
        Q_OBJECT
public:
        File(const Jid &_j);
        ~File();

        int total() const;
        void touch();
        PsiEvent *get(int);
        bool append(PsiEvent *);

signals:
        void timeout();

private slots:
        void timer_timeout();

public:
        Jid j;
        QString fname;
        QFile f;
        bool valid;
        QTimer *t;

        class Private;
        Private *d;

private:
        PsiEvent *lineToEvent(const QString &);
        QString eventToLine(PsiEvent *);
        void ensureIndex();
};

#endif