C++ QFile::exists方法代码示例

void Widget::Btn_onclicked()
{
    // 创建文件操作对象
    QFile *fp = new QFile("test.txt");

    // 检查文件是否存在
    if (!fp->exists()) {
        QMessageBox::critical(this, "Error", fp->errorString());
        return;
    }

    // 打开文件
    if (!fp->open(QIODevice::ReadWrite|QIODevice::Text)) {
        QMessageBox::critical(this, "Error", fp->errorString());
        return;
    }

    // 使用文本流对文件进行操作
    QTextStream out(fp);
    //out.setCodec("UTF-8");    // 设置编码
    QString text = out.readAll();
    ui->textEdit->setText(text);

    // 移动指针到末端并写入
    //fp->seek(fp->size());
    //out << "\r\n" << QString("321TEST");

    // 关闭文件
    fp->close();
    delete fp;

    // 设置textedit滚动到末端
    QTextCursor cursor = ui->textEdit->textCursor();
    cursor.movePosition(QTextCursor::End);
    ui->textEdit->setTextCursor(cursor);
}

void DepExportDialog::onExportButton_clicked()
{
  QString filename = QFileDialog::getSaveFileName( this, "Save file", "", ".csv");

  if (filename.isNull())
    return;

  QFile *outputFile = new QFile(filename);
  if (outputFile->exists()) {
    if ( QMessageBox::question(this, tr("Export"), tr("Die Datei %1 existiert bereits.\nMöchten Sie sie überschreiben?").arg(filename),
                                 QMessageBox::Yes, QMessageBox::No) == QMessageBox::No )
    {
      emit onExportButton_clicked();
      return;
    }
  }

  if (depExport(outputFile))
    QMessageBox::information(0, QObject::tr("Export"), QObject::tr("DEP (DatenErfassungsProtokoll) wurde nach %1 exportiert.").arg(filename));
  else
    QMessageBox::warning(0, QObject::tr("Export"), QObject::tr("DEP (DatenErfassungsProtokoll) konnte nicht nach %1 exportiert werden.\nÜberprüfen Sie bitte Ihre Schreibberechtigung.").arg(filename));

  this->close();
}

bool Model::importFile(const QFile& modelFile)
{
    if(!modelFile.exists())
    {
        qDebug() << "Model::importFile(): import file" << modelFile.fileName() << "does not exist!";
        return false;
    }

    mAssimpScene = mAssimpImporter.ReadFile(modelFile.fileName().toStdString(), aiProcessPreset_TargetRealtime_Quality);

    // If the import failed, report it
    if(!mAssimpScene)
    {
        qDebug() << "Model::importFile(): couldn't import file" << modelFile.fileName() << ":" << mAssimpImporter.GetErrorString();
        return false;
    }
    else
    {
//        qDebug() << "Model::importFile(): successfully imported file" << modelFile.fileName();
    }

    // We're done. Everything will be cleaned up by the importer destructor
    return true;
}

bool Bookmark::backupDatabase( QString file_name )
{
    configLS500 cfg ;
    QString file_name_bk ;

    if ( file_name.isEmpty() ) {
        QString bk_path = cfg.getBookmarkDumpPath() ;

        bk_path.replace( QRegExp( "(^\\$HOME)" ) , QDir::homePath() ) ;

        bk_path += "." ;
        bk_path += QDate::currentDate().toString( Qt::ISODate ) ;
        bk_path += "-" ;
        bk_path += QTime::currentTime().toString( Qt::ISODate ) ;

        QFile file ;
        int cnt = 1 ;

        file_name_bk = bk_path ;
        file.setFileName( file_name_bk );

        while( file.exists() ) {
            file_name_bk = bk_path + "." + "(" + QString().setNum(cnt++) + ")" ;
            file.setFileName( file_name_bk );
        }
    }

    QueryDB db ;

    int rc = db.backup( cfg.getBookmarkPath() , file_name_bk ) ;

    if ( rc == 0 )
        return true ;
    else
        return false ;
}

QFile* MainWindow::getRequiredFilesFile() {
    QSettings settings;
    //QString folder = settings.value("swg_folder").toString();

    QFile* file = NULL;

    //if (QDir(folder).exists()) {
        file = new QFile("required2.txt");

        if (file->exists()) {
            if (file->open(QIODevice::ReadOnly | QIODevice::Text)) {
                return file;
            } else
                delete file;
        } else {
            delete file;
        }
    //}

    file = new QFile(":/files/required2.txt");
    file->open(QIODevice::ReadOnly | QIODevice::Text);

    return file;
}

void UIImageOverview::deleteFile(void) {
    QFile f;
    QString filename;
    QString uri;
    QString cacheFile;

    filename = ui->listWidget->currentItem()->text();
    if (filename != "") {
        f.setFileName(filename);

        if (f.exists()) {
            f.remove();

            ui->listWidget->takeItem(ui->listWidget->currentRow());
        }

        if (getUrlOfFilename(filename, &uri))
            blackList->add(uri);
    }

    cacheFile = tnt->getCacheFile(filename);

    emit removeFiles(QStringList(cacheFile));
}

QString KGrGameIO::getFilePath
        (const QString & dir, const QString & prefix, const int level)
{
    QString filePath = ((level == 0) ? "ende" : prefix);
    filePath = dir + "game_" + filePath + ".txt";
    QFile test (filePath);

    // See if there is a game-file or "ENDE" screen in KGoldrunner 3 format.
    if (test.exists()) {
        return (filePath);
    }

    // If not, we are looking for a file in KGoldrunner 2 format.
    if (level == 0) {
        // End of game: show the "ENDE" screen.
        filePath = dir + "levels/level000.grl";
    }
    else {
        QString num = QString::number (level).rightJustified (3,'0');
        filePath = dir + "levels/" + prefix + num + ".grl";
    }

    return (filePath);
}

void Session::init() {
    qDebug() << "Loading sessions...";
    QFile* configFile = new QFile ( Core::configurationPath().absolutePath() +"/sessions.xml" );
    s_elems.clear();

    if ( s_dom ) {
        s_dom->clear();
        delete s_dom;
    }

    s_dom = new QDomDocument ( "Sessions" );

    if ( configFile->exists() ) {
        configFile->open ( QIODevice::ReadOnly );
        s_dom->setContent ( configFile );

        const QDomElement documentElem = s_dom->documentElement();
        const QDomNodeList l_domList = documentElem.elementsByTagName ( "Session" );

        for ( int i = 0; i < l_domList.count(); i++ ) {
            QDomElement l_node = l_domList.at ( i ).toElement();
            const QUuid l_uuid ( l_node.attribute ( "uuid" ) );
            s_elems.insert ( l_uuid, new QDomElement ( l_domList.at ( i ).toElement() ) );
        }

        qDebug() << l_domList.count() << "sessions loaded.";
    } else {
        configFile->open ( QIODevice::WriteOnly | QIODevice::Truncate );
        QDomElement l_elem = s_dom->createElement ( "Sessions" );
        s_dom->appendChild ( l_elem );
        configFile->write ( s_dom->toString ( 4 ).toLocal8Bit() );
        qDebug() << "Created session listing.";
    }

    configFile->close();
}

QIconTheme::QIconTheme(const QString &themeName)
        : m_valid(false)
{
    QFile themeIndex;

    QStringList iconDirs = QIcon::themeSearchPaths();
    for ( int i = 0 ; i < iconDirs.size() ; ++i) {
        QDir iconDir(iconDirs[i]);
        QString themeDir = iconDir.path() + QLatin1Char('/') + themeName;
        themeIndex.setFileName(themeDir + QLatin1String("/index.theme"));
        if (themeIndex.exists()) {
            m_contentDirs << themeDir;
            m_valid = true;

            QStringList themeSearchPaths = QIcon::themeSearchPaths();
            foreach (QString path, themeSearchPaths)
            {
                if (!path.startsWith(':') && QFileInfo(path).isDir())
                    m_contentDirs.append(path + QLatin1Char('/') + themeName);
            }

            break;
        }
    }

void MainWindow::loadfile(QString filename)
{
    QSettings settings;

    if(filename.isEmpty())
        filename = QFileDialog::getOpenFileName(this, tr("Open..."), settings.value("LoadFile/lastDirectory", QDir::homePath()).toString(), tr("FUSE files (*.fuse *.xml)"));

    if(filename.isEmpty())
        return;

    settings.setValue("LoadFile/lastDirectory", QFileInfo(filename).absolutePath());
    QFile *file = new QFile(filename, this);

    if(file->exists())
    {
        if (!file->open(QFile::ReadOnly | QFile::Text))
        {
            QMessageBox::critical(this, tr("Error!"), tr("Could not open file"));
            return;
        }
    }
    else
    {
        QMessageBox::critical(this, tr("Error!"), tr("No such file"));
        return;
    }

    struct amp_settings amplifier_set;
    struct fx_pedal_settings effects_set[4];
    QString name;
    LoadFromFile *loader = new LoadFromFile(file, &name, &amplifier_set, effects_set);

    loader->loadfile();
    file->close();
    delete loader;
    delete file;

    change_title(name);

    amp->load(amplifier_set);
    if(connected)
        amp->send_amp();
    if(settings.value("Settings/popupChangedWindows").toBool())
        amp->show();

    for(int i = 0; i < 4; i++)
    {
        switch(effects_set[i].fx_slot)
        {
        case 0x00:
            effect1->load(effects_set[i]);
            if(connected)
                effect1->send_fx();
            if(effects_set[i].effect_num)
                if(settings.value("Settings/popupChangedWindows").toBool())
                    effect1->show();
            break;

        case 0x01:
            effect2->load(effects_set[i]);
            if(connected)
                effect2->send_fx();
            if(effects_set[i].effect_num)
                if(settings.value("Settings/popupChangedWindows").toBool())
                    effect2->show();
            break;

        case 0x02:
            effect3->load(effects_set[i]);
            if(connected)
                effect3->send_fx();
            if(effects_set[i].effect_num)
                if(settings.value("Settings/popupChangedWindows").toBool())
                    effect3->show();
            break;

        case 0x03:
            effect4->load(effects_set[i]);
            if(connected)
                effect4->send_fx();
            if(effects_set[i].effect_num)
                if(settings.value("Settings/popupChangedWindows").toBool())
                    effect4->show();
            break;
        }
    }
}

void QgsApplication::init( QString customConfigPath )
{
  if ( customConfigPath.isEmpty() )
  {
    if ( getenv( "QGIS_CUSTOM_CONFIG_PATH" ) )
    {
      customConfigPath = getenv( "QGIS_CUSTOM_CONFIG_PATH" );
    }
    else
    {
      customConfigPath = QStringLiteral( "%1/.qgis3/" ).arg( QDir::homePath() );
    }
  }

  qRegisterMetaType<QgsGeometry::Error>( "QgsGeometry::Error" );
  qRegisterMetaType<QgsProcessingFeatureSourceDefinition>( "QgsProcessingFeatureSourceDefinition" );
  qRegisterMetaType<QgsProcessingOutputLayerDefinition>( "QgsProcessingOutputLayerDefinition" );

  QString prefixPath( getenv( "QGIS_PREFIX_PATH" ) ? getenv( "QGIS_PREFIX_PATH" ) : applicationDirPath() );
  // QgsDebugMsg( QString( "prefixPath(): %1" ).arg( prefixPath ) );

  // check if QGIS is run from build directory (not the install directory)
  QFile f;
  // "/../../.." is for Mac bundled app in build directory
  Q_FOREACH ( const QString &path, QStringList() << "" << "/.." << "/bin" << "/../../.." )
  {
    f.setFileName( prefixPath + path + "/qgisbuildpath.txt" );
    if ( f.exists() )
      break;
  }
  if ( f.exists() && f.open( QIODevice::ReadOnly ) )
  {
    ABISYM( mRunningFromBuildDir ) = true;
    ABISYM( mBuildSourcePath ) = f.readLine().trimmed();
    ABISYM( mBuildOutputPath ) = f.readLine().trimmed();
    qDebug( "Running from build directory!" );
    qDebug( "- source directory: %s", ABISYM( mBuildSourcePath ).toUtf8().data() );
    qDebug( "- output directory of the build: %s", ABISYM( mBuildOutputPath ).toUtf8().data() );
#ifdef _MSC_VER
    ABISYM( mCfgIntDir ) = prefixPath.split( '/', QString::SkipEmptyParts ).last();
    qDebug( "- cfg: %s", ABISYM( mCfgIntDir ).toUtf8().data() );
#endif
  }

  if ( ABISYM( mRunningFromBuildDir ) )
  {
    // we run from source directory - not installed to destination (specified prefix)
    ABISYM( mPrefixPath ) = QString(); // set invalid path
#if defined(_MSC_VER) && !defined(USING_NMAKE) && !defined(USING_NINJA)
    setPluginPath( ABISYM( mBuildOutputPath ) + '/' + QString( QGIS_PLUGIN_SUBDIR ) + '/' + ABISYM( mCfgIntDir ) );
#else
    setPluginPath( ABISYM( mBuildOutputPath ) + '/' + QStringLiteral( QGIS_PLUGIN_SUBDIR ) );
#endif
    setPkgDataPath( ABISYM( mBuildSourcePath ) ); // directly source path - used for: doc, resources, svg
    ABISYM( mLibraryPath ) = ABISYM( mBuildOutputPath ) + '/' + QGIS_LIB_SUBDIR + '/';
#if defined(_MSC_VER) && !defined(USING_NMAKE) && !defined(USING_NINJA)
    ABISYM( mLibexecPath ) = ABISYM( mBuildOutputPath ) + '/' + QGIS_LIBEXEC_SUBDIR + '/' + ABISYM( mCfgIntDir ) + '/';
#else
    ABISYM( mLibexecPath ) = ABISYM( mBuildOutputPath ) + '/' + QGIS_LIBEXEC_SUBDIR + '/';
#endif
  }
  else
  {
    char *prefixPath = getenv( "QGIS_PREFIX_PATH" );
    if ( !prefixPath )
    {
#if defined(Q_OS_MACX) || defined(Q_OS_WIN)
      setPrefixPath( applicationDirPath(), true );
#elif defined(ANDROID)
      // this is  "/data/data/org.qgis.qgis" in android
      QDir myDir( QDir::homePath() );
      myDir.cdUp();
      QString myPrefix = myDir.absolutePath();
      setPrefixPath( myPrefix, true );
#else
      QDir myDir( applicationDirPath() );
      myDir.cdUp();
      QString myPrefix = myDir.absolutePath();
      setPrefixPath( myPrefix, true );
#endif
    }
    else
    {
      setPrefixPath( prefixPath, true );
    }
  }

  if ( !customConfigPath.isEmpty() )
  {
    ABISYM( mConfigPath ) = customConfigPath + '/'; // make sure trailing slash is included
  }

  ABISYM( mDefaultSvgPaths ) << qgisSettingsDirPath() + QStringLiteral( "svg/" );

  ABISYM( mAuthDbDirPath ) = qgisSettingsDirPath();
  if ( getenv( "QGIS_AUTH_DB_DIR_PATH" ) )
  {
    setAuthDatabaseDirPath( getenv( "QGIS_AUTH_DB_DIR_PATH" ) );
  }

//.........这里部分代码省略.........

bool plotsDialog::loadXml(bool init)
{
    tabs->clear();
    QFile file;
#ifdef Q_OS_WIN32
    if(init)
    {
        QFile ofile(globalpara.caseName);
        file.setFileName("plotTemp.xml");
        if(file.exists())
            file.remove();
        if(!ofile.copy("plotTemp.xml"))
        {
            globalpara.reportError("Fail to generate temporary file for plots.",this);
            return false;
        }
        else file.setFileName("plotTemp.xml");
    }
    else file.setFileName("plotTemp.xml");
#endif
#ifdef Q_OS_MAC
    QDir dir = qApp->applicationDirPath();
    /*dir.cdUp();*/
    /*dir.cdUp();*/
    /*dir.cdUp();*/
    QString bundleDir(dir.absolutePath());
    if(init)
    {
        QFile ofile(globalpara.caseName);
        file.setFileName(bundleDir+"/plotTemp.xml");
        if(file.exists())
            file.remove();
        if(!ofile.copy(bundleDir+"/plotTemp.xml"))
        {
            globalpara.reportError("Fail to generate temporary file for plots.",this);
            return false;
        }
        else file.setFileName(bundleDir+"/plotTemp.xml");
    }
    else file.setFileName(bundleDir+"/plotTemp.xml");
#endif
    QDomDocument doc;
    QDomElement plotData, currentPlot;
    int plotCount=0;
    Plot*newPlot;

    if(!file.open(QIODevice::ReadOnly | QIODevice::Text))
    {
        globalpara.reportError("Fail to open the xml file for plots!",this);
        return false;
    }
    else
    {
        if(!doc.setContent(&file))
        {
            globalpara.reportError("Fail to set DomDoc to file content when loading xml file for plots!",this);
            file.close();
            return false;
        }
        else
        {
            if(doc.elementsByTagName("plotData").count()==0)
            {
                globalpara.reportError("Error! There is no <plotData> branch in the case xml file!",this);
                file.close();
                return false;
            }
            else
                plotData = doc.elementsByTagName("plotData").at(0).toElement();

            plotCount = plotData.childNodes().count();
            for(int i = 0; i < plotCount; i++)
            {
                currentPlot = plotData.childNodes().at(i).toElement();
                if(currentPlot.attribute("plotType")=="parametric")
                {
                    QDomElement currentRun,runInput,runOutput;
                    double currentInput;
                    int axis_info[8];
                    QStringList currentOutput, xValues, axis_name, info;
                    QMultiMap<double,double> allData;
                    axis_name.append(currentPlot.attribute("xAxisName"));
                    axis_name= axis_name + currentPlot.attribute("yAxisName").split(",");
                    info = currentPlot.attribute("scaleInfo").split(",");
                    for(int j = 0; j < 8; j++)
                        axis_info[j] = info.at(j).toInt();
                    int nRuns = currentPlot.elementsByTagName("Run").count(), nOutputs = currentPlot.attribute("outputs").toInt();
                    for(int j = 0; j < nRuns; j++)
                    {
                        currentOutput.clear();
                        currentRun = currentPlot.elementsByTagName("Run").at(j).toElement();
                        runInput = currentRun.elementsByTagName("Input").at(0).toElement();
                        currentInput = runInput.elementsByTagName("value").at(0).toElement().text().toDouble();
                        xValues.append(QString::number(currentInput));
                        for(int p = 0; p < nOutputs; p++)
                        {
                            runOutput = currentRun.elementsByTagName("Output").at(p).toElement();
                            currentOutput.append(runOutput.elementsByTagName("value").at(0).toElement().text());
                            allData.insert(currentInput,currentOutput.at(p).toDouble());
                        }
//.........这里部分代码省略.........

bool XmlDataLayer::invoiceInsertData(InvoiceData& oi_invData, int type) {
        qDebug() << __FILE__ << __LINE__ << __FUNCTION__;

	QDomDocument doc(sett().getInoiveDocName());
	QDomElement root;
	QString fileName = oi_invData.id;

	QFile file;
	if (fileName == "") {
		fileName = QDate::currentDate().toString(sett().getFnameDateFormat());

		int pNumber = 0;
		file.setFileName(sett().getInvoicesDir() + "h" + fileName + "_"
				+ sett().numberToString(pNumber) + ".xml");
		oi_invData.id = "h" + fileName + "_" + sett().numberToString(pNumber) + ".xml";
		pNumber += 1;

		while (file.exists()) {
			file.setFileName(sett().getInvoicesDir() + "h" + fileName + "_"
					+ sett().numberToString(pNumber) + ".xml");
			oi_invData.id = "h" + fileName + "_" + sett().numberToString(pNumber) + ".xml";
			pNumber += 1;
		}

		// fName = "h" + fileName + "_" + sett().numberToString(pNumber) + ".xml";
	} else {
		file.setFileName(sett().getInvoicesDir() + fileName);
		oi_invData.id = fileName + "|";
	}

	// if (!file.open (QIODevice::ReadOnly)) {

	root = doc.createElement("invoice");
	root.setAttribute("no", oi_invData.frNr);
	oi_invData.issueDate = QDate::currentDate();
	root.setAttribute("issueDate", oi_invData.issueDate.toString(sett().getDateFormat()));
	root.setAttribute("sellingDate", oi_invData.sellingDate.toString(sett().getDateFormat()));

	QString invType = oi_invData.getInvoiceTypeAndSaveNr(type);
	root.setAttribute("type", invType);

	doc.appendChild(root);

	QDomElement sprzedawca = doc.createElement("seller");
	invoiceSellerDataToElem(oi_invData, sprzedawca);
	root.appendChild(sprzedawca);


	QDomElement nabywca = doc.createElement("buyer");
	invoiceBuyerDataToElem(oi_invData, nabywca);
	root.appendChild(nabywca);

	QDomElement product;
	QDomElement products;
	products = doc.createElement("products");
	products.setAttribute("discount", sett().numberToString(oi_invData.discount));

	QMap<int, ProductData>::const_iterator i = oi_invData.products.constBegin();
	int abc = 0;
	while (i != oi_invData.products.constEnd()) {
		product = doc.createElement("product");
		// ProductData pr = i.value();
		invoiceProdDataToElem(i.value(), product);
		products.appendChild(product);
		i++;
	}

	root.appendChild(products);

	QDomElement addinfo;
	addinfo = doc.createElement("addinfo");
	addinfo.setAttribute("text", oi_invData.additText);
	addinfo.setAttribute("paymentType", oi_invData.paymentType );
	addinfo.setAttribute("liabDate", oi_invData.liabDate.toString(sett().getDateFormat()));
	addinfo.setAttribute("currency", oi_invData.currencyType);

	/*
	if (platCombo->currentIndex() == sett().value("payments").toString().split("|").count() - 1) {
		addinfo.setAttribute("payment1", custPaymData->payment1);
		addinfo.setAttribute("amount1", sett().numberToString(custPaymData->amount1, 'f', 2));
		addinfo.setAttribute("liabDate1", custPaymData->date1.toString(
				sett().getDateFormat()));

		addinfo.setAttribute("payment2", custPaymData->payment2);
		addinfo.setAttribute("amount2", sett().numberToString(custPaymData->amount2, 'f', 2));
		addinfo.setAttribute("liabDate2", custPaymData->date2.toString(
				sett().getDateFormat()));
	}
	*/
	root.appendChild(addinfo);

	QString xml = doc.toString();
	file.close();
	if (!file.open(QIODevice::WriteOnly)) {
		// saveFailed = true;
		return false;
	}
	QTextStream ts(&file);
	ts << xml;
	file.close();
//.........这里部分代码省略.........

/** Anm. JH
 * Hier wird das Graphik-Modell geladen?
 * @brief Methode zum einbinden der STL-Dateien
 */
int readSTL(QVector <triangle> *triangleList, QString path)
{
    int triCount = 0;
    int strIndex = 0;

    QFile file (path);
    QTextStream stream(&file);
    QString line, strX, strY, strZ, value;
    GLfloat tempPoints[3][3] = {{0.0,0.0,0.0},{0.0,0.0,0.0},{0.0,0.0,0.0}};
    triangle tri;

    strX = ""; strY = ""; strZ = "";
    value = "0123456789+-.e";

    if(!file.exists())
    {
        qDebug()<< "STL-Datei"<<path<<"existiert nicht! Ende.";
        assert(false);
    }


    file.open(QIODevice::ReadOnly);

    while(!stream.atEnd())
    {
        line = stream.readLine();
        if(line.contains("outer loop") && triCount != 0)
            return RETURN_OK;
        else if(line.contains("endloop") && triCount != 3)
            return RETURN_ERROR;
        else if(line.contains("endloop") && triCount == 3)
        {
            triCount = 0;
            memmove(tri.vertex0, tempPoints[0], sizeof(tempPoints[0]));
            memmove(tri.vertex1, tempPoints[1], sizeof(tempPoints[0]));
            memmove(tri.vertex2, tempPoints[2], sizeof(tempPoints[0]));
            getNormal(tri.normal, tri.vertex0, tri.vertex1, tri.vertex2);
            (*triangleList).push_back(tri);
        }
        else if((strIndex = line.lastIndexOf("vertex",-1)) != -1)
        {
            strIndex+=7;
            while(value.contains(line[strIndex]))
            {
                strX+=line[strIndex];
                strIndex++;
            };
            strIndex++;
            while(value.contains(line[strIndex]))
            {
                strY+=line[strIndex];
                strIndex++;
            };
            strIndex++;
            while(value.contains(line[strIndex]))
            {
                strZ+=line[strIndex];
                strIndex++;
            };
            tempPoints[triCount][0] = strX.toDouble();
            tempPoints[triCount][1] = strY.toDouble();
            tempPoints[triCount][2] = strZ.toDouble();

            strX.clear();
            strY.clear();
            strZ.clear();

            triCount++;
        }
    };
    file.close(); // Datei wieder schließen

    return RETURN_OK;
}

/*! \brief Extracts the selected .tar.gz archive to the selected folder, will try to create the target folder if it does not exist.
* @param filePath Full path to selected archive.
* @param targetFolderPath Full path to target folder.
* @return Returns full path to the extracted archive, or empty QString if failed.
*/
QString ArchiveExtractor::extractFileToTargetFolder(QString filePath, QString targetFolderPath){
  //check if the selected archive file exist
  QFile *selectedFile = new QFile(filePath);
  if(!selectedFile->exists()){
    qDebug()<<"ERROR: File marked for decompression does not exist!";
    delete selectedFile;
    return QString("");
  }
  delete selectedFile;
  struct archive *a;
  struct archive *ext;
  struct archive_entry *entry;
  int r;
  //  /* The "flags" argument selects optional behavior, 'OR' the flags you want. */
  //  /* Default: Do not try to set owner/group. */
  //#define	ARCHIVE_EXTRACT_OWNER			(0x0001)
  //  /* Default: Do obey umask, do not restore SUID/SGID/SVTX bits. */
  //#define	ARCHIVE_EXTRACT_PERM			(0x0002)
  //  /* Default: Do not restore mtime/atime. */
  //#define	ARCHIVE_EXTRACT_TIME			(0x0004)
  //  /* Default: Replace existing files. */
  //#define	ARCHIVE_EXTRACT_NO_OVERWRITE 		(0x0008)
  //  /* Default: Try create first, unlink only if create fails with EEXIST. */
  //#define	ARCHIVE_EXTRACT_UNLINK			(0x0010)
  //  /* Default: Do not restore ACLs. */
  //#define	ARCHIVE_EXTRACT_ACL			(0x0020)
  //  /* Default: Do not restore fflags. */
  //#define	ARCHIVE_EXTRACT_FFLAGS			(0x0040)
  //  /* Default: Do not restore xattrs. */
  //#define	ARCHIVE_EXTRACT_XATTR 			(0x0080)
  //  /* Default: Do not try to guard against extracts redirected by symlinks. */
  //  /* Note: With ARCHIVE_EXTRACT_UNLINK, will remove any intermediate symlink. */
  //#define	ARCHIVE_EXTRACT_SECURE_SYMLINKS		(0x0100)
  //  /* Default: Do not reject entries with '..' as path elements. */
  //#define	ARCHIVE_EXTRACT_SECURE_NODOTDOT		(0x0200)
  //  /* Default: Create parent directories as needed. */
  //#define	ARCHIVE_EXTRACT_NO_AUTODIR		(0x0400)
  //  /* Default: Overwrite files, even if one on disk is newer. */
  //#define	ARCHIVE_EXTRACT_NO_OVERWRITE_NEWER	(0x0800)
  //  /* Detect blocks of 0 and write holes instead. */
  //#define	ARCHIVE_EXTRACT_SPARSE			(0x1000)
  //  /* Default: Do not restore Mac extended metadata. */
  //  /* This has no effect except on Mac OS. */
  //#define	ARCHIVE_EXTRACT_MAC_METADATA		(0x2000)
  int flags = 0;
  //      flags |= ARCHIVE_EXTRACT_TIME;
  //      flags |= ARCHIVE_EXTRACT_NO_AUTODIR;
  //      flags |= ARCHIVE_EXTRACT_NO_OVERWRITE_NEWER;

  QFileInfo *fileInfo = new QFileInfo(filePath);
//  qDebug()<<"resolved filename: "<<fileInfo->fileName();
  delete fileInfo;

  //MEMORY LEAK!!! (Pointers be dangerous, man. :)
  //  const char *filename = fileInfo->fileName().toUtf8().constData();
  //AVOID IT BY CONVERTING TO A QBYTEARRAY FIRST!
  QByteArray byteArray = filePath.toUtf8();
  const char *filename = byteArray.constData();
  //That's better :D

  //toggle extraction
  bool do_extract = true;

  a = archive_read_new();
  ext = archive_write_disk_new();
  archive_write_disk_set_options(ext, flags);

  //tuned for .tar.gz
  archive_read_support_filter_gzip(a);
  archive_read_support_format_gnutar(a);

  if((r = archive_read_open_filename(a, filename, 10240)) ){
    errmsg(archive_error_string(a));
  }
  for(;;){
    r = archive_read_next_header(a, &entry);
    if(r == ARCHIVE_EOF) break;
    if(r != ARCHIVE_OK){
      errmsg(archive_error_string(a));
    }
    if (verbose || !do_extract){
      qDebug()<<"Detected files in archive: ";
      msg(archive_entry_pathname(entry));
    }
    QString currentPath(archive_entry_pathname( entry ));
    qDebug()<<currentPath;

    QDir targetFolder(targetFolderPath);
    if(!targetFolder.exists()){//target folder does not exist
      //attempt to create it
      if(!targetFolder.mkpath(targetFolderPath)){//failed to create target folder
        //break procedure
        qDebug()<<"ERROR: Target folder does not exist and cannot be created";
        return QString("");
      }
//.........这里部分代码省略.........