synchtimer.h

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/*
 *  synchtimer.h  -  timers which synchronize to time boundaries
 *  Program:  kalarm
 *  Copyright © 2004,2005 by David Jarvie <djarvie@kde.org>
 *
 *  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 program; if not, write to the Free Software Foundation, Inc.,
 *  51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
 */

#ifndef SYNCHTIMER_H
#define SYNCHTIMER_H

/* @file synchtimer.h - timers which synchronize to time boundaries */

#include <QObject>
#include <QList>
#include <QByteArray>
#include <QDateTime>
class QTimer;

class SynchTimer : public QObject
{
        Q_OBJECT
    public:
        virtual ~SynchTimer();

        struct Connection
        {
            Connection() { }
            Connection(QObject* r, const char* s) : receiver(r), slot(s) { }
            bool operator==(const Connection& c) const  { return receiver == c.receiver && slot == c.slot; }
            QObject*   receiver;
            QByteArray slot;
        };
    protected:
        SynchTimer();
        virtual void        start() = 0;
        void                connecT(QObject* receiver, const char* member);
        void                disconnecT(QObject* receiver, const char* member = 0);
        bool                hasConnections() const   { return !mConnections.isEmpty(); }

        QTimer*             mTimer;

    protected slots:
        virtual void        slotTimer() = 0;

    private slots:
        void                slotReceiverGone(QObject* r)  { disconnecT(r); }

    private:
        SynchTimer(const SynchTimer&);   // prohibit copying
        QList<Connection>   mConnections;  // list of current clients
};


class MinuteTimer : public SynchTimer
{
        Q_OBJECT
    public:
        virtual ~MinuteTimer()  { mInstance = 0; }
        static void connect(QObject* receiver, const char* member)
                           { instance()->connecT(receiver, member); }
        static void disconnect(QObject* receiver, const char* member = 0)
                           { if (mInstance) mInstance->disconnecT(receiver, member); }

    protected:
        MinuteTimer() : SynchTimer() { }
        static MinuteTimer* instance();
        virtual void        start()    { slotTimer(); }

    protected slots:
        virtual void slotTimer();

    private:
        static MinuteTimer* mInstance;     // the one and only instance
};


class DailyTimer : public SynchTimer
{
        Q_OBJECT
    public:
        virtual ~DailyTimer();
        static void connect(const QTime& timeOfDay, QObject* receiver, const char* member)
                           { fixedInstance(timeOfDay)->connecT(receiver, member); }
        static void disconnect(const QTime& timeOfDay, QObject* receiver, const char* member = 0);
        void changeTime(const QTime& newTimeOfDay, bool triggerMissed = true);
        QTime timeOfDay() const  { return mTime; }

    protected:
        DailyTimer(const QTime&, bool fixed);
        static DailyTimer* fixedInstance(const QTime& timeOfDay, bool create = true);
        virtual void start();

    protected slots:
        virtual void slotTimer();

    private:
        static QList<DailyTimer*>  mFixedTimers;   // list of timers whose trigger time is fixed
        QTime  mTime;
        QDate  mLastDate;  // the date on which the timer was last triggered
        bool   mFixed;     // the time at which the timer triggers cannot be changed
};


class MidnightTimer
{
    public:
        static void connect(QObject* receiver, const char* member)
                           { DailyTimer::connect(QTime(0,0), receiver, member); }
        static void disconnect(QObject* receiver, const char* member = 0)
                           { DailyTimer::disconnect(QTime(0,0), receiver, member); }

};

#endif // SYNCHTIMER_H

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