qt-everywhere-src-5.15.1/qtmultimedia/src/multimedia/qmediapluginloader.cpp

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#include "qmediapluginloader_p.h"
#include <QtCore/qcoreapplication.h>
#include <QtCore/qdebug.h>
#include <QtCore/qjsonarray.h>
#include <private/qfactoryloader_p.h>

#include "qmediaserviceproviderplugin.h"

QT_BEGIN_NAMESPACE

QMediaPluginLoader::QMediaPluginLoader(const char *iid, const QString &location, Qt::CaseSensitivity caseSensitivity):
    m_iid(iid)
{
#if defined(Q_OS_ANDROID)
    m_location = QString(location).replace(QLatin1Char('/'), QLatin1Char('_'));
#else
    m_location = QString::fromLatin1("/%1").arg(location);
#endif
    m_factoryLoader = new QFactoryLoader(m_iid, m_location, caseSensitivity);
    loadMetadata();
}

QMediaPluginLoader::~QMediaPluginLoader()
{
    delete m_factoryLoader;
}

QStringList QMediaPluginLoader::keys() const
{
    return m_metadata.keys();
}

QObject* QMediaPluginLoader::instance(QString const &key)
{
    if (!m_metadata.contains(key))
        return nullptr;

    int idx = m_metadata.value(key).first().value(QStringLiteral("index")).toDouble();
    if (idx < 0)
        return nullptr;

    return m_factoryLoader->instance(idx);
}

QList<QObject*> QMediaPluginLoader::instances(QString const &key)
{
    if (!m_metadata.contains(key))
        return QList<QObject*>();

    QList<QString> keys;
    QList<QObject *> objects;
    const auto list = m_metadata.value(key);
    for (const QJsonObject &jsonobj : list) {
        int idx = jsonobj.value(QStringLiteral("index")).toDouble();
        if (idx < 0)
            continue;

        QObject *object = m_factoryLoader->instance(idx);
        if (!objects.contains(object)) {
            QJsonArray arr = jsonobj.value(QStringLiteral("Keys")).toArray();
            keys.append(!arr.isEmpty() ? arr.at(0).toString() : QStringLiteral(""));
            objects.append(object);
        }
    }

    static const bool showDebug = qEnvironmentVariableIntValue("QT_DEBUG_PLUGINS");
    static const QStringList preferredPlugins =
        qEnvironmentVariable("QT_MULTIMEDIA_PREFERRED_PLUGINS").split(QLatin1Char(','), Qt::SkipEmptyParts);
    for (int i = preferredPlugins.size() - 1; i >= 0; --i) {
        auto name = preferredPlugins[i];
        bool found = false;
        for (int j = 0; j < keys.size(); ++j) {
            if (!keys[j].startsWith(name))
                continue;

            auto obj = objects[j];
            objects.removeAt(j);
            objects.prepend(obj);
            auto k = keys[j];
            keys.removeAt(j);
            keys.prepend(k);
            found = true;
            break;
        }

        if (showDebug && !found)
            qWarning() << "QMediaPluginLoader: pattern" << name << "did not match any loaded plugin";
    }

    if (showDebug)
        qDebug() << "QMediaPluginLoader: loaded plugins for key" << key << ":" << keys;

    return objects;
}

void QMediaPluginLoader::loadMetadata()
{
#if !defined QT_NO_DEBUG
    const bool showDebug = qgetenv("QT_DEBUG_PLUGINS").toInt() > 0;
#endif

#if !defined QT_NO_DEBUG
        if (showDebug)
            qDebug() << "QMediaPluginLoader: loading metadata for iid " << m_iid << " at location " << m_location;
#endif

    if (!m_metadata.isEmpty()) {
#if !defined QT_NO_DEBUG
        if (showDebug)
            qDebug() << "QMediaPluginLoader: already loaded metadata, returning";
#endif
        return;
    }

    QList<QJsonObject> meta = m_factoryLoader->metaData();
    for (int i = 0; i < meta.size(); i++) {
        QJsonObject jsonobj = meta.at(i).value(QStringLiteral("MetaData")).toObject();
        jsonobj.insert(QStringLiteral("index"), i);
#if !defined QT_NO_DEBUG
        if (showDebug)
            qDebug() << "QMediaPluginLoader: Inserted index " << i << " into metadata: " << jsonobj;
#endif

        QJsonArray arr = jsonobj.value(QStringLiteral("Services")).toArray();
        // Preserve compatibility with older plugins (made before 5.1) in which
        // services were declared in the 'Keys' property
        if (arr.isEmpty())
            arr = jsonobj.value(QStringLiteral("Keys")).toArray();

        for (const QJsonValue &value : qAsConst(arr)) {
            QString key = value.toString();

            if (!m_metadata.contains(key)) {
#if !defined QT_NO_DEBUG
                if (showDebug)
                    qDebug() << "QMediaPluginLoader: Inserting new list for key: " << key;
#endif
                m_metadata.insert(key, QList<QJsonObject>());
            }

            m_metadata[key].append(jsonobj);
        }
    }
}

QT_END_NAMESPACE