waitcondition.h

Linux下比较早的基于命令行的DVD播放器

//
// Copyright (c) 2003 by Istv醤 V醨adi
//
// This file is part of dxr3Player, a DVD player written specifically 
// for the DXR3 (aka Hollywood+) decoder card.

// 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 DXR3PLAYER_SCHED_WAITCONDITION_H
#define DXR3PLAYER_SCHED_WAITCONDITION_H
//------------------------------------------------------------------------------

#include <cstdlib>
#include <cstring>
#include <cassert>

//------------------------------------------------------------------------------

namespace sched {

//------------------------------------------------------------------------------

class Schedulable;

//------------------------------------------------------------------------------

/**
 * Waiting condition. It describes when the waiting can be finished,
 * because the condition a schedulable has been waiting for is fulfilled.
 */
class WaitCondition
{
private:
    /**
     * The name of the wait condition's owner.
     */
    const char* ownerName;

    /**
     * The name of the wait condition.
     */
    const char* name;

    /**
     * The schedulable waiting on the condition.
     */
    Schedulable* waiter;

    /**
     * Indicate if the condition has been fulfilled.
     */
    bool fulfilled;

public:
    /**
     * Construct the condition assigned to the given object having the
     * given name.
     */
    WaitCondition(const char* ownerName, const char* name);

    /**
     * Get the owner's name.
     */
    const char* getOwnerName() const;

    /**
     * Get the name.
     */
    const char* getName() const;

    /**
     * Set the condition.
     */
    void set();

    /**
     * Check if the condition is fulfilled.
     */
    bool check() const;

    /**
     * Check if the condition has a waiter.
     */
    bool hasWaiter() const;

private:
    /**
     * Initialize the condition. It clears the fulfilment indicater
     * and sets the waiter.
     */
    void init(Schedulable* w, bool f = false);

    /**
     * Clear the condition and the waiter.
     *
     * @return if the condition had been fulfilled
     */
    bool clear();

    friend class Schedulable;
};

//------------------------------------------------------------------------------
// Inline definitions
//------------------------------------------------------------------------------

inline WaitCondition::WaitCondition(const char* ownerName, const char * name) :
    ownerName(ownerName),
    name(name),
    waiter(0),
    fulfilled(false)
{
}

//------------------------------------------------------------------------------

inline const char* WaitCondition::getOwnerName() const
{
    return ownerName;
}

//------------------------------------------------------------------------------

inline const char* WaitCondition::getName() const
{
    return name;
}

//------------------------------------------------------------------------------

inline void WaitCondition::set()
{
    if (waiter!=0) {
        fulfilled = true;
    }
}

//------------------------------------------------------------------------------

inline bool WaitCondition::check() const
{
    return waiter!=0 && fulfilled;
}

//------------------------------------------------------------------------------

inline bool WaitCondition::hasWaiter() const
{
    return waiter!=0;
}

//------------------------------------------------------------------------------

inline void WaitCondition::init(Schedulable* w, bool f)
{
    assert(!hasWaiter());

    waiter = w;
    fulfilled = f;
}

//------------------------------------------------------------------------------

inline bool WaitCondition::clear()
{
    bool f = fulfilled;

    waiter = 0;
    fulfilled = false;

    return f;
}

//------------------------------------------------------------------------------

} /* namespace sched */

//------------------------------------------------------------------------------
#endif // DXR3PLAYER_SCHED_WAITCONDITION_H

// Local variables:
// mode: c++
// End: