suspender.h

/*
 *  Copyright (C) 2006  Helmut Grohne
 *
 *  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., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 */

#ifndef LIBMUTH_SUSPENDER_H
#define LIBMUTH_SUSPENDER_H

#include <assert.h>
#include "suspender_decls.h"
#include "currentthread.h"

template<class T> T Suspender<T>::suspend() {
        this->lock.acquire();
        assert(this->microthread == NULL);
        if(!this->wakened) {
                Microthread *m(this->microthread = &getcurrentthread());
                this->lock.release();
                m->delayme();
        } else
                this->lock.release();
        assert(this->wakened == true);
        return this->retval;
}

template<class T> bool Suspender<T>::wakeup(const T &rv) {
        this->lock.acquire();
        if(this->wakened) {
                this->lock.release();
                return false;
        }
        this->retval = rv;
        this->wakened = true;
        if(Microthread *m = this->microthread) {
                this->lock.release();
                m->scheduleme();
        } else
                this->lock.release();
        return true;
}

template<class T> bool Suspender<T>::cooperativewakeup(const T &rv) {
        this->lock.acquire();
        if(this->wakened) {
                this->lock.release();
                return false;
        }
        this->wakened = true;
        this->retval = rv;
        if(Microthread *m = this->microthread) {
                this->lock.release();
                Microthread &me(getcurrentthread());
                me.scheduleme();
                me.swapto(*m);
        } else
                this->lock.release();
        return true;
}

template<class T> inline bool Suspender<T>::issuspended() const {
        /* TODO: unlocked! necessary? */
        return this->microthread != NULL && !this->wakened;
}

template<class T> inline bool Suspender<T>::iswakened() const {
        /* TODO: unlocked! necessary? */
        return this->wakened;
}

template<class T> inline bool Suspender<T>::iscompleted() const {
        /* TODO: unlocked! necessary? */
        return this->microthread != NULL && this->wakened;
}

#endif

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