/*

* Copyright (c) 2009 Nokia Corporation and/or its subsidiary(-ies).

* All rights reserved.

* This component and the accompanying materials are made available

* under the terms of "Eclipse Public License v1.0""

* which accompanies this distribution, and is available

* at the URL "http://www.eclipse.org/legal/epl-v10.html".

*

* Initial Contributors:

* Nokia Corporation - initial contribution.

*

* Contributors:

*

* Description:  

*

*/

#ifndef CPTASKEXECUTOR_H

#define CPTASKEXECUTOR_H

#include <cpcategoryglobal.h>

#include <QThread>

#include <QList>

#include <QMutex>

class CpTask

{

public:

    explicit CpTask(bool autoDelete = true) 

    : mAutoDelete(autoDelete)

    {

    }

    virtual ~CpTask()

    {

    }

    bool autoDelete() const 

    {

        return mAutoDelete;

    }

    virtual void execute(volatile bool *stopped)

    {

        Q_UNUSED(stopped);

    }

    virtual void complete(volatile bool *stopped)

    {

        Q_UNUSED(stopped);

    }

private:

    bool mAutoDelete;

};

class CP_CATEGORY_EXPORT CpTaskExecutor : public QThread

{

    Q_OBJECT

public:

    explicit CpTaskExecutor(QObject *parent = 0);

    virtual ~CpTaskExecutor();

    /*

    return the gloabl instance

    */

    static CpTaskExecutor *globalInstance();

    /*

    destroy the global instance 

    */

    static void destroyGlobalInstance();

    /*

    add the task to running queue

    @task the task

    @append ture -- append to tail false -- preappend to head

    */

    bool runTask(CpTask *task,bool append = false);

    /*

    stop the thread and remove all not running tasks

    */

    void stop();

    /*

    move a task to front of the queue

    */

    bool toFront(CpTask *task);

    /*

    move a task to front of the queue

    */

    template <typename Predicate> bool toFront(Predicate pred);

protected:

    /*

    From QThread, run tasks

    */

    virtual void run();

private:

    /*

    remove not running tasks

    */

    void removeTasks();

private:

    QList<CpTask*> mTasks;

    QMutex mMutex;

    volatile bool mStopped;

};

template<typename Predicate>

bool CpTaskExecutor::toFront(Predicate pred)

{

    QMutexLocker locker(&mMutex);

    QList<CpTask*>::iterator workIterator = mTasks.begin();

    QList<CpTask*>::iterator endIterator(mTasks.end());

    for(;workIterator != endIterator;++workIterator)

    {

        if (pred(*workIterator)) {

            break;

        }

    }

    if (workIterator == endIterator) {

        return false;

    }

    CpTask *task = *workIterator;

    mTasks.erase(workIterator);

    mTasks.insert(0,task);

    return true;

}

#endif  //CPTASKECECUTOR_H

//End of File