C++ QFactoryLoader::instance方法代码示例

/*!
    Returns the list of image formats supported by QImageWriter.

    By default, Qt can write the following formats:

    \table
    \header \o Format \o Description
    \row    \o BMP    \o Windows Bitmap
    \row    \o JPG    \o Joint Photographic Experts Group
    \row    \o JPEG   \o Joint Photographic Experts Group
    \row    \o PNG    \o Portable Network Graphics
    \row    \o PPM    \o Portable Pixmap
    \row    \o TIFF   \o Tagged Image File Format
    \row    \o XBM    \o X11 Bitmap
    \row    \o XPM    \o X11 Pixmap
    \endtable

    \sa setFormat(), QImageReader::supportedImageFormats(), QImageIOPlugin
*/
QList<QByteArray> QImageWriter::supportedImageFormats()
{
    QSet<QByteArray> formats;
    formats << "bmp";
#ifndef QT_NO_IMAGEFORMAT_PPM
    formats << "ppm";
#endif
#ifndef QT_NO_IMAGEFORMAT_XBM
    formats << "xbm";
#endif
#ifndef QT_NO_IMAGEFORMAT_XPM
    formats << "xpm";
#endif
#ifndef QT_NO_IMAGEFORMAT_PNG
    formats << "png";
#endif

#ifndef QT_NO_LIBRARY
    QFactoryLoader *l = loader();
    QStringList keys = l->keys();
    for (int i = 0; i < keys.count(); ++i) {
        QImageIOPlugin *plugin = qobject_cast<QImageIOPlugin *>(l->instance(keys.at(i)));
        if (plugin && (plugin->capabilities(0, keys.at(i).toLatin1()) & QImageIOPlugin::CanWrite) != 0)
            formats << keys.at(i).toLatin1();
    }
#endif // QT_NO_LIBRARY

    QList<QByteArray> sortedFormats;
    for (QSet<QByteArray>::ConstIterator it = formats.constBegin(); it != formats.constEnd(); ++it)
        sortedFormats << *it;

    qSort(sortedFormats);
    return sortedFormats;
}

static QTextCodec *createForName(const QByteArray &name)
{
#ifndef QT_NO_TEXTCODECPLUGIN
    QFactoryLoader *l = loader();
    QStringList keys = l->keys();
    for (int i = 0; i < keys.size(); ++i) {
        if (nameMatch(name, keys.at(i).toLatin1())) {
            QString realName = keys.at(i);
            if (QTextCodecFactoryInterface *factory
                    = qobject_cast<QTextCodecFactoryInterface*>(l->instance(realName))) {
                return factory->create(realName);
            }
        }
    }
#else
    Q_UNUSED(name);
#endif
    return 0;
}

QList<QAudioDeviceInfo> QAudioDeviceFactory::availableDevices(QAudio::Mode mode)
{
    QList<QAudioDeviceInfo> devices;
#ifndef QT_NO_AUDIO_BACKEND
#if (defined(Q_OS_WIN) || defined(Q_OS_MAC) || defined(HAS_ALSA) || defined(Q_OS_SYMBIAN))
    foreach (const QByteArray &handle, QAudioDeviceInfoInternal::availableDevices(mode))
        devices << QAudioDeviceInfo(QLatin1String("builtin"), handle, mode);
#endif
#endif
#if !defined(QT_NO_LIBRARY) && !defined(QT_NO_SETTINGS)
    QFactoryLoader* l = loader();

    foreach (QString const& key, l->keys()) {
        QAudioEngineFactoryInterface* plugin = qobject_cast<QAudioEngineFactoryInterface*>(l->instance(key));
        if (plugin) {
            foreach (QByteArray const& handle, plugin->availableDevices(mode))
                devices << QAudioDeviceInfo(key, handle, mode);
        }

        delete plugin;
    }
#endif
    return devices;
}

static QImageIOHandler *createWriteHandler(QIODevice *device, const QByteArray &format)
{
    QByteArray form = format.toLower();
    QByteArray suffix;
    QImageIOHandler *handler = 0;

#ifndef QT_NO_LIBRARY
    // check if any plugins can write the image
    QFactoryLoader *l = loader();
    QStringList keys = l->keys();
    int suffixPluginIndex = -1;
#endif

    if (device && format.isEmpty()) {
        // if there's no format, see if \a device is a file, and if so, find
        // the file suffix and find support for that format among our plugins.
        // this allows plugins to override our built-in handlers.
        if (QFile *file = qobject_cast<QFile *>(device)) {
            if (!(suffix = QFileInfo(file->fileName()).suffix().toLower().toLatin1()).isEmpty()) {
#ifndef QT_NO_LIBRARY
                int index = keys.indexOf(QString::fromLatin1(suffix));
                if (index != -1)
                    suffixPluginIndex = index;
#endif
            }
        }
    }

    QByteArray testFormat = !form.isEmpty() ? form : suffix;

#ifndef QT_NO_LIBRARY
    if (suffixPluginIndex != -1) {
        // when format is missing, check if we can find a plugin for the
        // suffix.
        QImageIOPlugin *plugin = qobject_cast<QImageIOPlugin *>(l->instance(QString::fromLatin1(suffix)));
        if (plugin && (plugin->capabilities(device, suffix) & QImageIOPlugin::CanWrite))
            handler = plugin->create(device, suffix);
    }
#endif // Q_NO_LIBRARY

    // check if any built-in handlers can write the image
    if (!handler && !testFormat.isEmpty()) {
        if (false) {
#ifndef QT_NO_IMAGEFORMAT_PNG
        } else if (testFormat == "png") {
            handler = new QPngHandler;
#endif
#ifndef QT_NO_IMAGEFORMAT_BMP
        } else if (testFormat == "bmp") {
            handler = new QBmpHandler;
#endif
#ifndef QT_NO_IMAGEFORMAT_XPM
        } else if (testFormat == "xpm") {
            handler = new QXpmHandler;
#endif
#ifndef QT_NO_IMAGEFORMAT_XBM
        } else if (testFormat == "xbm") {
            handler = new QXbmHandler;
            handler->setOption(QImageIOHandler::SubType, testFormat);
#endif
#ifndef QT_NO_IMAGEFORMAT_PPM
        } else if (testFormat == "pbm" || testFormat == "pbmraw" || testFormat == "pgm"
                 || testFormat == "pgmraw" || testFormat == "ppm" || testFormat == "ppmraw") {
            handler = new QPpmHandler;
            handler->setOption(QImageIOHandler::SubType, testFormat);
#endif
        }
    }

#ifndef QT_NO_LIBRARY
    if (!testFormat.isEmpty()) {
        for (int i = 0; i < keys.size(); ++i) {
            QImageIOPlugin *plugin = qobject_cast<QImageIOPlugin *>(l->instance(keys.at(i)));
            if (plugin && (plugin->capabilities(device, testFormat) & QImageIOPlugin::CanWrite)) {
                handler = plugin->create(device, testFormat);
                break;
            }
        }
    }
#endif

    if (!handler)
        return 0;

    handler->setDevice(device);
    if (!testFormat.isEmpty())
        handler->setFormat(testFormat);
    return handler;
}

static QImageIOHandler *createReadHandlerHelper(QIODevice *device,
                                                const QByteArray &format,
                                                bool autoDetectImageFormat,
                                                bool ignoresFormatAndExtension)
{
    if (!autoDetectImageFormat && format.isEmpty())
        return 0;

    QByteArray form = format.toLower();
    QImageIOHandler *handler = 0;
    QByteArray suffix;

#ifndef QT_NO_IMAGEFORMATPLUGIN
    static QMutex mutex;
    QMutexLocker locker(&mutex);

    typedef QMultiMap<int, QString> PluginKeyMap;

    // check if we have plugins that support the image format
    QFactoryLoader *l = loader();
    const PluginKeyMap keyMap = l->keyMap();

#ifdef QIMAGEREADER_DEBUG
    qDebug() << "QImageReader::createReadHandler( device =" << (void *)device << ", format =" << format << "),"
             << keyMap.values().size() << "plugins available: " << keyMap.values();
#endif

    int suffixPluginIndex = -1;
#endif // QT_NO_IMAGEFORMATPLUGIN

    if (device && format.isEmpty() && autoDetectImageFormat && !ignoresFormatAndExtension) {
        // if there's no format, see if \a device is a file, and if so, find
        // the file suffix and find support for that format among our plugins.
        // this allows plugins to override our built-in handlers.
        if (QFile *file = qobject_cast<QFile *>(device)) {
#ifdef QIMAGEREADER_DEBUG
            qDebug() << "QImageReader::createReadHandler: device is a file:" << file->fileName();
#endif
            if (!(suffix = QFileInfo(file->fileName()).suffix().toLower().toLatin1()).isEmpty()) {
#ifndef QT_NO_IMAGEFORMATPLUGIN
                const int index = keyMap.key(QString::fromLatin1(suffix), -1);
                if (index != -1) {
#ifdef QIMAGEREADER_DEBUG
                    qDebug() << "QImageReader::createReadHandler: suffix recognized; the"
                             << suffix << "plugin might be able to read this";
#endif
                    suffixPluginIndex = index;
                }
#endif // QT_NO_IMAGEFORMATPLUGIN
            }
        }
    }

    QByteArray testFormat = !form.isEmpty() ? form : suffix;

    if (ignoresFormatAndExtension)
        testFormat = QByteArray();

#ifndef QT_NO_IMAGEFORMATPLUGIN
    if (suffixPluginIndex != -1) {
        // check if the plugin that claims support for this format can load
        // from this device with this format.
        const qint64 pos = device ? device->pos() : 0;
        const int index = keyMap.key(QString::fromLatin1(suffix), -1);
        if (index != -1) {
            QImageIOPlugin *plugin = qobject_cast<QImageIOPlugin *>(l->instance(index));
            if (plugin && plugin->capabilities(device, testFormat) & QImageIOPlugin::CanRead) {
                handler = plugin->create(device, testFormat);
#ifdef QIMAGEREADER_DEBUG
                qDebug() << "QImageReader::createReadHandler: using the" << suffix
                         << "plugin";
#endif
            }
        }
        if (device && !device->isSequential())
            device->seek(pos);
    }

    if (!handler && !testFormat.isEmpty() && !ignoresFormatAndExtension) {
        // check if any plugin supports the format (they are not allowed to
        // read from the device yet).
        const qint64 pos = device ? device->pos() : 0;

        if (autoDetectImageFormat) {
            const int keyCount = keyMap.keys().size();
            for (int i = 0; i < keyCount; ++i) {
                if (i != suffixPluginIndex) {
                    QImageIOPlugin *plugin = qobject_cast<QImageIOPlugin *>(l->instance(i));
                    if (plugin && plugin->capabilities(device, testFormat) & QImageIOPlugin::CanRead) {
#ifdef QIMAGEREADER_DEBUG
                        qDebug() << "QImageReader::createReadHandler: the" << keyMap.keys().at(i) << "plugin can read this format";
#endif
                        handler = plugin->create(device, testFormat);
                        break;
                    }
                }
            }
        } else {
            const int testIndex = keyMap.key(QLatin1String(testFormat), -1);
            if (testIndex != -1) {
//.........这里部分代码省略.........

static QImageIOHandler *createWriteHandlerHelper(QIODevice *device,
    const QByteArray &format)
{
    QByteArray form = format.toLower();
    QByteArray suffix;
    QImageIOHandler *handler = 0;

#ifndef QT_NO_IMAGEFORMATPLUGIN
    typedef QMultiMap<int, QString> PluginKeyMap;

    // check if any plugins can write the image
    QFactoryLoader *l = loader();
    const PluginKeyMap keyMap = l->keyMap();
    int suffixPluginIndex = -1;
#endif

    if (device && format.isEmpty()) {
        // if there's no format, see if \a device is a file, and if so, find
        // the file suffix and find support for that format among our plugins.
        // this allows plugins to override our built-in handlers.
        if (QFile *file = qobject_cast<QFile *>(device)) {
            if (!(suffix = QFileInfo(file->fileName()).suffix().toLower().toLatin1()).isEmpty()) {
#ifndef QT_NO_IMAGEFORMATPLUGIN
                const int index = keyMap.key(QString::fromLatin1(suffix), -1);
                if (index != -1)
                    suffixPluginIndex = index;
#endif
            }
        }
    }

    QByteArray testFormat = !form.isEmpty() ? form : suffix;

#ifndef QT_NO_IMAGEFORMATPLUGIN
    if (suffixPluginIndex != -1) {
        // when format is missing, check if we can find a plugin for the
        // suffix.
        const int index = keyMap.key(QString::fromLatin1(suffix), -1);
        if (index != -1) {
            QImageIOPlugin *plugin = qobject_cast<QImageIOPlugin *>(l->instance(index));
            if (plugin && (plugin->capabilities(device, suffix) & QImageIOPlugin::CanWrite))
                handler = plugin->create(device, suffix);
        }
    }
#endif // QT_NO_IMAGEFORMATPLUGIN

    // check if any built-in handlers can write the image
    if (!handler && !testFormat.isEmpty()) {
        if (false) {
#ifndef QT_NO_IMAGEFORMAT_PNG
        } else if (testFormat == "png") {
            handler = new QPngHandler;
#endif
#ifndef QT_NO_IMAGEFORMAT_JPEG
        } else if (testFormat == "jpg" || testFormat == "jpeg") {
            handler = new QJpegHandler;
#endif
#ifdef QT_BUILTIN_GIF_READER
        } else if (testFormat == "gif") {
            handler = new QGifHandler;
#endif
#ifndef QT_NO_IMAGEFORMAT_BMP
        } else if (testFormat == "bmp") {
            handler = new QBmpHandler;
        } else if (testFormat == "dib") {
            handler = new QBmpHandler(QBmpHandler::DibFormat);
#endif
#ifndef QT_NO_IMAGEFORMAT_XPM
        } else if (testFormat == "xpm") {
            handler = new QXpmHandler;
#endif
#ifndef QT_NO_IMAGEFORMAT_XBM
        } else if (testFormat == "xbm") {
            handler = new QXbmHandler;
            handler->setOption(QImageIOHandler::SubType, testFormat);
#endif
#ifndef QT_NO_IMAGEFORMAT_PPM
        } else if (testFormat == "pbm" || testFormat == "pbmraw" || testFormat == "pgm"
                 || testFormat == "pgmraw" || testFormat == "ppm" || testFormat == "ppmraw") {
            handler = new QPpmHandler;
            handler->setOption(QImageIOHandler::SubType, testFormat);
#endif
        }
    }

#ifndef QT_NO_IMAGEFORMATPLUGIN
    if (!testFormat.isEmpty()) {
        const int keyCount = keyMap.keys().size();
        for (int i = 0; i < keyCount; ++i) {
            QImageIOPlugin *plugin = qobject_cast<QImageIOPlugin *>(l->instance(i));
            if (plugin && (plugin->capabilities(device, testFormat) & QImageIOPlugin::CanWrite)) {
                delete handler;
                handler = plugin->create(device, testFormat);
                break;
            }
        }
    }
#endif // QT_NO_IMAGEFORMATPLUGIN

    if (!handler)
//.........这里部分代码省略.........

QList<QAudioDeviceInfo> QAudioDeviceFactory::deviceList(QAudio::Mode mode)
{
    QList<QAudioDeviceInfo> devices;
#if (defined(Q_OS_WIN) || defined(Q_OS_MAC) || defined(HAS_ALSA))
    foreach (const QByteArray &handle, QAudioDeviceInfoInternal::deviceList(mode))
        devices << QAudioDeviceInfo(QLatin1String("builtin"), handle, mode);
#endif
    QFactoryLoader* l = loader();

    foreach (QString const& key, l->keys()) {
        QAudioEngineFactoryInterface* plugin = qobject_cast<QAudioEngineFactoryInterface*>(l->instance(key));
        if (plugin) {
            foreach (QByteArray const& handle, plugin->deviceList(mode))
                devices << QAudioDeviceInfo(key, handle, mode);
        }

        delete plugin;
    }

    return devices;
}