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****************************************************************************/

#include "qsensormanager.h"

#include <QDebug>

#include "qsensorpluginloader_p.h"

#include "qsensorplugin.h"

#include <QSettings>

QTM_BEGIN_NAMESPACE

Q_GLOBAL_STATIC_WITH_ARGS(QSensorPluginLoader, pluginLoader, (QSensorPluginInterface_iid, QLatin1String("/sensors")))

typedef QHash<QByteArray,QSensorBackendFactory*> FactoryForIdentifierMap;

typedef QHash<QByteArray,FactoryForIdentifierMap> BackendIdentifiersForTypeMap;

class QSensorManagerPrivate

{

public:

    QSensorManagerPrivate()

        : pluginsLoaded(false)

    {

    }

    bool pluginsLoaded;

    QList<CreatePluginFunc> staticRegistrations;

    // Holds a mapping from type to available identifiers (and from there to the factory)

    BackendIdentifiersForTypeMap backendsByType;

    // Holds the first identifier for each type

    QHash<QByteArray, QByteArray> firstIdentifierForType;

};

Q_GLOBAL_STATIC(QSensorManagerPrivate, sensorManagerPrivate)

static void loadPlugins()

{

    QSensorManagerPrivate *d = sensorManagerPrivate();

    d->pluginsLoaded = true;

    Q_FOREACH (CreatePluginFunc func, d->staticRegistrations) {

        QSensorPluginInterface *plugin = func();

        plugin->registerSensors();

    }

    Q_FOREACH (QSensorPluginInterface *plugin, pluginLoader()->plugins()) {

        plugin->registerSensors();

    }

}

// =====================================================================

/*!

    \class QSensorManager

    \ingroup sensors_backend

    \preliminary

*/

/*!

    Register a sensor for \a type. The \a identifier must be unique.

    The \a factory will be asked to create instances of the backend.

*/

void QSensorManager::registerBackend(const QByteArray &type, const QByteArray &identifier, QSensorBackendFactory *factory)

{

    QSensorManagerPrivate *d = sensorManagerPrivate();

    if (!d->backendsByType.contains(type)) {

        (void)d->backendsByType[type];

        d->firstIdentifierForType[type] = identifier;

    }

    FactoryForIdentifierMap &factoryByIdentifier = d->backendsByType[type];

    factoryByIdentifier[identifier] = factory;

}

/*!

    \internal

*/

void QSensorManager::registerStaticPlugin(CreatePluginFunc func)

{

    QSensorManagerPrivate *d = sensorManagerPrivate();

    d->staticRegistrations.append(func);

}

/*!

    Create a backend for \a sensor. Returns null if no suitable backend exists.

*/

QSensorBackend *QSensorManager::createBackend(QSensor *sensor)

{

    Q_ASSERT(sensor);

    QSensorManagerPrivate *d = sensorManagerPrivate();

    if (!d->pluginsLoaded)

        loadPlugins();

    if (!d->backendsByType.contains(sensor->type())) {

        return 0;

    }

    const FactoryForIdentifierMap &factoryByIdentifier = d->backendsByType[sensor->type()];

    QSensorBackendFactory *factory;

    QSensorBackend *backend;

    if (sensor->identifier().isEmpty()) {

        QByteArray defaultIdentifier = QSensor::defaultSensorForType(sensor->type());

        // No identifier set, try the default

        factory = factoryByIdentifier[defaultIdentifier];

        sensor->setIdentifier(defaultIdentifier); // the factory requires this

        backend = factory->createBackend(sensor);

        // The default failed to instantiate so try any other registered sensors for this type

        Q_FOREACH (const QByteArray &identifier, factoryByIdentifier.keys()) {

            if (identifier == defaultIdentifier) continue; // Don't do the default one again

            factory = factoryByIdentifier[identifier];

            sensor->setIdentifier(identifier); // the factory requires this

            backend = factory->createBackend(sensor);

        }

        sensor->setIdentifier(QByteArray()); // clear the identifier

    } else {

        if (!factoryByIdentifier.contains(sensor->identifier())) {

            return 0;

        }

        // We were given an explicit identifier so don't substitute other backends if it fails to instantiate

        factory = factoryByIdentifier[sensor->identifier()];

        backend = factory->createBackend(sensor);

    }

    return 0;

}

// =====================================================================

/*!

    Returns a list of all sensor types.

*/

QList<QByteArray> QSensor::sensorTypes()

{

    QSensorManagerPrivate *d = sensorManagerPrivate();

    if (!d->pluginsLoaded)

        loadPlugins();

    return d->backendsByType.keys();

}

/*!

    Returns a list of ids for each of the sensors for \a type.

    If there are no sensors of that type available the list will be empty.

*/

QList<QByteArray> QSensor::sensorsForType(const QByteArray &type)

{

    QSensorManagerPrivate *d = sensorManagerPrivate();

    if (!d->pluginsLoaded)

        loadPlugins();

    return d->backendsByType[type].keys();

}

/*!

    Returns the default sensor identifier for \a type.

    This is set in a config file and can be overridden if required.

    If no default is available the system will return the first registered

    sensor for \a type.

*/

QByteArray QSensor::defaultSensorForType(const QByteArray &type)

{

    QSensorManagerPrivate *d = sensorManagerPrivate();

    if (!d->pluginsLoaded)

        loadPlugins();

    // no sensors of that type exist

    if (!d->backendsByType.contains(type))

        return QByteArray();

    QSettings settings(QLatin1String("Nokia"), QLatin1String("Sensors"));

    QVariant value = settings.value(QString(QLatin1String("Default/%1")).arg(QString::fromLatin1(type)));

    if (!value.isNull()) {

        QByteArray defaultIdentifier = value.toByteArray();

        if (d->backendsByType[type].contains(defaultIdentifier)) // Don't return a value that we can't use!

            return defaultIdentifier;

    }

    // This is our fallback

    return d->firstIdentifierForType[type];

}

// =====================================================================

/*!

    \class QSensorBackendFactory

    \ingroup sensors_backend

    \preliminary

    \brief The QSensorBackendFactory class instantiates instances of

           QSensorBackend.

    This interface must be implemented in order to register a sensor backend.

    \sa {Creating a sensor plugin}

*/

/*!

    \fn QSensorBackendFactory::~QSensorBackendFactory()

    \internal

*/

/*!

    \fn QSensorBackendFactory::createBackend(QSensor *sensor)

    Instantiate a backend. If the factory handles multiple identifiers

    it should check with the \a sensor to see which one is requested.

    If the factory cannot create a backend it should return 0.

*/

/*!

    \macro REGISTER_STATIC_PLUGIN(pluginname)

    \relates QSensorManager

    Registers a static plugin, \a pluginname.

    Note that this macro relies on static initialization so it may not be appropriate

    for use in a library and may not work on all platforms.

    \sa {Creating a sensor plugin}

*/

QTM_END_NAMESPACE