InterruptableAsyncWorker.h

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/* Copyright (C) 2008 AbiSource Corporation B.V.
 *
 * 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 __INTERRUPTABLE_ASYNC_WORKER__
#define __INTERRUPTABLE_ASYNC_WORKER__

#ifdef _MSC_VER
#include "msc_stdint.h"
#else
#include <stdint.h>
#endif
#include <boost/bind.hpp>
#include "xap_App.h"
#include "xap_DialogFactory.h"
#include "AsyncWorker.h"
#include "ap_Dialog_GenericProgress.h"
#include "ServiceAccountHandler.h"

class InterruptedException {};
class InternalErrorException {};

template <class T>
class InterruptableAsyncWorker : public boost::enable_shared_from_this< InterruptableAsyncWorker<T> >
{
public:
    InterruptableAsyncWorker(boost::function<T ()> async_func)
        : m_async_func(async_func),
        m_worker_ptr(),
        m_pProgressDlg(NULL),
        m_progress(0),
        m_cancelled(false),
        m_finished(false),
        m_progressSynchronizerPtr(),
        m_result()
    {}

    T run()
    {
        UT_DEBUGMSG(("InterruptableAsyncWorker::run()\n"));

        m_worker_ptr.reset(new AsyncWorker<T>(m_async_func, boost::bind(&InterruptableAsyncWorker<T>::invoke_cb, InterruptableAsyncWorker<T>::shared_from_this(), _1)));
        m_progressSynchronizerPtr.reset(new Synchronizer(boost::bind(&InterruptableAsyncWorker<T>::_updateDialog, InterruptableAsyncWorker<T>::shared_from_this())));

        // get the progress dialog
        XAP_Frame* pFrame = XAP_App::getApp()->getLastFocussedFrame();
        if (!pFrame)
            throw InternalErrorException();

        XAP_DialogFactory* pFactory = static_cast<XAP_DialogFactory *>(XAP_App::getApp()->getDialogFactory());
        if (!pFactory)
            throw InternalErrorException();

        m_pProgressDlg = static_cast<AP_Dialog_GenericProgress*>(
                    pFactory->requestDialog(ServiceAccountHandler::getDialogGenericProgressId())
                );
        m_pProgressDlg->setTitle("Retrieving Document");
        m_pProgressDlg->setInformation("Please wait while retrieving document...");

        // start the asynchronous process
        m_worker_ptr->start();

        // run the dialog
        m_pProgressDlg->runModal(pFrame);
        UT_DEBUGMSG(("Progress dialog destroyed...\n"));
        m_cancelled = m_pProgressDlg->getAnswer() == AP_Dialog_GenericProgress::a_CANCEL;
        pFactory->releaseDialog(m_pProgressDlg);
        m_pProgressDlg = NULL;
        if (m_cancelled)
            throw InterruptedException();
        return m_result;
    }

    bool cancelled()
    {
        return m_cancelled;
    }

    void progress(uint32_t _progress)
    {
        UT_DEBUGMSG(("InterruptableAsyncWorker::_progress_cb() - %d\n", _progress));
        UT_return_if_fail(m_progressSynchronizerPtr);

        if (_progress > 100)
            _progress = 100;

        m_progress = _progress;
        m_progressSynchronizerPtr->signal();
    }

    // the result of run() is undefined when using this function
    void forceFinished()
    {
        m_finished = true;
        m_progressSynchronizerPtr->signal();
    }

private:
    void invoke_cb(T result)
    {
        UT_DEBUGMSG(("InterruptableAsyncWorker::invoke_cb()\n"));
        m_result = result;

        // signal the mainloop that we are done
        m_finished = true;
        m_progressSynchronizerPtr->signal();
    }

    void _updateDialog()
    {
        UT_DEBUGMSG(("InterruptableAsyncWorker::_updateDialog()\n"));
        if (m_finished)
        {
            UT_DEBUGMSG(("We are finished, closing dialog...\n"));
            if (m_pProgressDlg)
            {
                m_pProgressDlg->close();
            }
            else
            {
                UT_DEBUGMSG(("Skipping dialog closure; it is destructed already\n"));
            }
        }
        else
        {
            UT_DEBUGMSG(("Setting progress value to %d%%\n", m_progress));
            if (m_pProgressDlg) // it could be that we have no dialog when we have been cancelled
            {
                m_pProgressDlg->setProgress(m_progress);
            }
            else
            {
                UT_DEBUGMSG(("Skipping dialog progress update; it is destructed already\n"));
            }
        }
    }

    boost::function<T ()>               m_async_func;
    boost::shared_ptr< AsyncWorker<T> > m_worker_ptr;

    AP_Dialog_GenericProgress*          m_pProgressDlg;
    uint32_t                            m_progress;
    bool                                m_cancelled;
    bool                                m_finished;
    boost::shared_ptr<Synchronizer>     m_progressSynchronizerPtr;

    T                                   m_result;
};

#endif /* __INTERRUPTABLE_ASYNC_WORKER__ */