code_app/modules/saneui/dialog_device_scan.cpp

#include "dialog_device_scan.h"
#include "ui_dialog_device_scan.h"
#include "base/HGInc.h"
#include <QMessageBox>
#include <QCloseEvent>

Dialog_Device_Scan::Dialog_Device_Scan(const SANEAPI* saneApi, SANE_Handle dev, const char *devName,
                                       show_scan_ui_image_callback callback, void *callbackParam, QWidget *parent) :
    QDialog(parent),
    ui(new Ui::Dialog_Device_Scan)
{
    ui->setupUi(this);

    memcpy(&m_saneAPI, saneApi, sizeof(SANEAPI));
    m_saneDev = dev;
    m_callback = callback;
    m_callbackParam = callbackParam;
    m_buffer = NULL;
    m_bufferSize = 0;
    m_stopThread = HGFALSE;
    m_thread = NULL;

    setWindowTitle(QString::fromStdString(devName));
    setWindowFlags(Qt::Dialog | Qt::WindowCloseButtonHint);

    qRegisterMetaType<SANE_Parameters>("SANE_Parameters");
    qRegisterMetaType<SANE_Byte *>("SANE_Byte *");
    connect(this, &Dialog_Device_Scan::eventFunc, this, &Dialog_Device_Scan::on_eventFunc, Qt::QueuedConnection);

    ui->pushButton_Continue->setEnabled(true);
    ui->pushButton_Cancel->setEnabled(false);
    ui->pushButton_Complete->setEnabled(true);

    on_pushButton_Continue_clicked();
}

Dialog_Device_Scan::~Dialog_Device_Scan()
{
    delete ui;
}

void Dialog_Device_Scan::on_eventFunc(QString errInfo)
{
    ui->listWidget->addItem(errInfo);
    ui->listWidget->scrollToBottom();

    m_stopThread = HGTRUE;
    m_saneAPI.sane_cancel_api(m_saneDev);
    HGBase_CloseThread(m_thread);
    m_thread = NULL;

    free(m_buffer);
    m_buffer = NULL;
    m_bufferSize = 0;

    ui->pushButton_Continue->setEnabled(true);
    ui->pushButton_Cancel->setEnabled(false);
    ui->pushButton_Complete->setEnabled(true);
}

void Dialog_Device_Scan::on_pushButton_Cancel_clicked()
{
    m_saneAPI.sane_cancel_api(m_saneDev);
}

void Dialog_Device_Scan::on_pushButton_Complete_clicked()
{
    accept();
}

void Dialog_Device_Scan::on_pushButton_Continue_clicked()
{
    SANE_Parameters params;
    memset(&params, 0, sizeof(SANE_Parameters));
    SANE_Status stat = m_saneAPI.sane_get_parameters_api(m_saneDev, &params);
    assert(SANE_STATUS_GOOD == stat);

    m_bufferSize = 5000 * 4000;
    m_buffer = (HGByte *)malloc(m_bufferSize);
    if (NULL == m_buffer)
    {
        ui->listWidget->addItem(tr("Out of memory"));
        ui->listWidget->scrollToBottom();
        return;
    }

    m_stopThread = HGFALSE;
    HGBase_OpenThread(ThreadFunc, this, &m_thread);

    ui->pushButton_Continue->setEnabled(false);
    ui->pushButton_Cancel->setEnabled(true);
    ui->pushButton_Complete->setEnabled(false);

    ui->listWidget->addItem(tr("Start scan"));
    ui->listWidget->scrollToBottom();
}

void Dialog_Device_Scan::closeEvent(QCloseEvent *e)
{
    if (nullptr != m_thread)
    {
        QMessageBox::warning(this, tr("Warning"), tr("Scanning in progress, closing not allowed"));
        e->ignore();
        return;
    }
}

void HGAPI Dialog_Device_Scan::ThreadFunc(HGThread thread, HGPointer param)
{
    Dialog_Device_Scan* p = (Dialog_Device_Scan*)param;

    SANE_Status stat = p->m_saneAPI.sane_start_api(p->m_saneDev);
    if (SANE_STATUS_GOOD != stat)
    {
        emit p->eventFunc(QString::fromUtf8(p->m_saneAPI.sane_strstatus_api(stat)));
        return;
    }

    while (!p->m_stopThread)
    {
        SANE_Parameters params;
        memset(&params, 0, sizeof(SANE_Parameters));
        SANE_Status stat1 = p->m_saneAPI.sane_get_parameters_api(p->m_saneDev, &params);

        SANE_Int readSize = 0;
        SANE_Status stat2 = SANE_STATUS_GOOD;
        while (readSize < p->m_bufferSize)
        {
            SANE_Int len = 0;
            stat2 = p->m_saneAPI.sane_read_api(p->m_saneDev, p->m_buffer + readSize, p->m_bufferSize - readSize, &len);
            readSize += len;
            if (SANE_STATUS_GOOD != stat2)
            {
                break;
            }
        }

        if (SANE_STATUS_GOOD == stat2)
        {
            // m_bufferSize空间不够
            emit p->eventFunc(QString::fromUtf8(p->m_saneAPI.sane_strstatus_api(SANE_STATUS_INVAL)));
            break;
        }
        else if (SANE_STATUS_EOF == stat2)
        {
            if (0 == readSize)
            {
                emit p->eventFunc(tr("Scan complete"));
                break;
            }
            else if (SANE_STATUS_GOOD != stat1 || readSize != params.bytes_per_line * params.lines)
            {
                emit p->eventFunc(QString::fromUtf8(p->m_saneAPI.sane_strstatus_api(SANE_STATUS_INVAL)));
                break;
            }
        }
        else if (SANE_STATUS_CANCELLED == stat2)
        {
            break;
        }
        else
        {
            emit p->eventFunc(QString::fromUtf8(p->m_saneAPI.sane_strstatus_api(stat2)));
            break;
        }

        if (nullptr != p->m_callback)
            p->m_callback(&params, p->m_buffer, p->m_callbackParam);
    }
}