/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */

/*

 * This file is part of the LibreOffice project.

 *

 * This Source Code Form is subject to the terms of the Mozilla Public

 * License, v. 2.0. If a copy of the MPL was not distributed with this

 * file, You can obtain one at http://mozilla.org/MPL/2.0/.

 *

 * This file incorporates work covered by the following license notice:

 *

 *   Licensed to the Apache Software Foundation (ASF) under one or more

 *   contributor license agreements. See the NOTICE file distributed

 *   with this work for additional information regarding copyright

 *   ownership. The ASF licenses this file to you under the Apache

 *   License, Version 2.0 (the "License"); you may not use this file

 *   except in compliance with the License. You may obtain a copy of

 *   the License at http://www.apache.org/licenses/LICENSE-2.0 .

 */

#include <tools/TimerBasedTaskExecution.hxx>

#include <tools/AsynchronousTask.hxx>

#include <tools/time.hxx>

#include <sal/log.hxx>

#include <memory>

#include <utility>

namespace sdtools {

/** Used by the shared_ptr instead of the private destructor.

*/

class TimerBasedTaskExecution::Deleter

{

public:

    void operator() (TimerBasedTaskExecution* pObject)

    {

        delete pObject;

    }

};

std::shared_ptr<TimerBasedTaskExecution> TimerBasedTaskExecution::Create (

    const std::shared_ptr<AsynchronousTask>& rpTask,

    sal_uInt32 nMillisecondsBetweenSteps,

    sal_uInt32 nMaxTimePerStep)

{

    std::shared_ptr<TimerBasedTaskExecution> pExecution(

        new TimerBasedTaskExecution(rpTask,nMillisecondsBetweenSteps,nMaxTimePerStep),

        Deleter());

    // Let the new object have a shared_ptr to itself, so that it can

    // release itself when the AsynchronousTask has been executed

    // completely.

    if (pExecution->mpTask != nullptr)

        pExecution->mpSelf = pExecution;

    return pExecution;

}

void TimerBasedTaskExecution::Release()

{

    maTimer.Stop();

    mpSelf.reset();

}

//static

void TimerBasedTaskExecution::ReleaseTask (

    const std::weak_ptr<TimerBasedTaskExecution>& rpExecution)

{

    if (  rpExecution.expired())

        return;

    try

    {

        std::shared_ptr<sdtools::TimerBasedTaskExecution> pExecution (rpExecution);

        pExecution->Release();

    }

    catch (const std::bad_weak_ptr&)

    {

        // When a bad_weak_ptr has been thrown then the object pointed

        // to by rpTask has been released right after we checked that it

        // still existed.  Too bad, but that means, that we have nothing

        // more do.

    }

}

TimerBasedTaskExecution::TimerBasedTaskExecution (

    std::shared_ptr<AsynchronousTask> pTask,

    sal_uInt32 nMillisecondsBetweenSteps,

    sal_uInt32 nMaxTimePerStep)

    : mpTask(std::move(pTask)),

      maTimer("sd TimerBasedTaskExecution maTimer"),

      mnMaxTimePerStep(nMaxTimePerStep)

{

    maTimer.SetInvokeHandler( LINK(this,TimerBasedTaskExecution,TimerCallback) );

    maTimer.SetTimeout(nMillisecondsBetweenSteps);

    maTimer.Start();

}

TimerBasedTaskExecution::~TimerBasedTaskExecution()

{

    maTimer.Stop();

}

IMPL_LINK_NOARG(TimerBasedTaskExecution, TimerCallback, Timer *, void)

{

    if (mpTask == nullptr)

        return;

    if (mpTask->HasNextStep())

    {

        // Execute as many steps as fit into the time span of length

        // mnMaxTimePerStep.  Note that the last step may take longer

        // than allowed.

        sal_uInt32 nStartTime (::tools::Time( ::tools::Time::SYSTEM ).GetMSFromTime());

        SAL_INFO("sd.tools", __func__ << ": starting TimerBasedTaskExecution at " << nStartTime);

        do

        {

            mpTask->RunNextStep();

            sal_uInt32 nDuration (::tools::Time( ::tools::Time::SYSTEM ).GetMSFromTime()-nStartTime);

            SAL_INFO("sd.tools", __func__ << ": executed step in " << nDuration);

            if (nDuration > mnMaxTimePerStep)

                break;

        }

        while (mpTask->HasNextStep());

        SAL_INFO("sd.tools", __func__ << ": TimerBasedTaskExecution sleeping");

        maTimer.Start();

    }

    else

        mpSelf.reset();

}

} // end of namespace ::sdtools

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