path: root/src/nfc/qnearfieldmanager.cpp

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#include "qnearfieldmanager.h"
#include "qnearfieldmanager_p.h"

#if defined(QT_SIMULATOR)
#include "qnearfieldmanager_simulator_p.h"
#elif defined(Q_WS_MAEMO_6) || defined (Q_WS_MEEGO)
#include "qnearfieldmanager_maemo6_p.h"
#else
#include "qnearfieldmanagerimpl_p.h"
#endif

#include <QtCore/QMetaType>
#include <QtCore/QMetaMethod>

QTNFC_BEGIN_NAMESPACE

/*!
    \class QNearFieldManager
    \brief The QNearFieldManager class provides access to notifications for NFC events.

    \ingroup connectivity-nfc
    \inmodule QtNfc

    NFC Forum devices support two modes of communications.  The first mode, peer-to-peer
    communications, is used to communicate between two NFC Forum devices.  The second mode,
    master/slave communications, is used to communicate between an NFC Forum device and an NFC
    Forum Tag or Contactless Card.  The targetDetected() signal is emitted when a target device
    enters communications range.  Communications can be initiated from the slot connected to this
    signal.

    NFC Forum devices generally operate as the master in master/slave communications. Some devices
    are also capable of operating as the slave, so called Card Emulation mode. In this mode the
    local NFC device emulates a NFC Forum Tag or Contactless Card and can be used to perform
    transactions. The transaction happens entirely within a secure element on the device and only a
    notification of the transaction is provided. The transactionDetected() signal is emitted
    whenever a transaction occurs.

    NFC Forum Tags can contain one or more messages in a standardized format. These messages are
    encapsulated by the QNdefMessage class. Use the registerNdefMessageHandler() functions to
    register message handlers with particular criteria. Handlers can be unregistered with the
    unregisterNdefMessageHandler() function.

    Applications can connect to the targetDetected() and targetLost() signals to get notified when
    an NFC Forum Device or NFC Forum Tag enters or leaves proximity. Before these signals are
    emitted target detection must be started with the startTargetDetection() function, which takes
    a parameter to limit the type of device or tags detected. Target detection can be stopped with
    the stopTargetDetection() function. Before a detected target can be accessed it is necessary to
    request access rights. This must be done before the target device is touched. The
    setTargetAccessModes() function is used to set the types of access the application wants to
    perform on the detected target. When access is no longer required the target access modes
    should be set to NoTargetAccess as other applications may be blocked from accessing targets.
    The current target access modes can be retried with the targetAccessModes() function.


    \section2 Automatically launching NDEF message handlers

    It is possible to pre-register an application to receive NDEF messages matching a given
    criteria. This is useful to get the system to automatically launch your application when a
    matching NDEF message is received. This removes the need to have the user manually launch NDEF
    handling applications, prior to touching a tag, or to have those applications always running
    and using system resources.

    The process of registering the handler is different on each platform. The platform specifics
    are documented in the sections below. QtNfc provides a tool, \c {ndefhandlergen}, to
    generate the platform specific registration files. The output of \c {ndefhandlergen -help} is
    reproduced here for convenience:

    \code
        Generate platform specific NFC message handler registration files.
        Usage: nfcxmlgen [options]

            -template TEMPLATE    Template to use.
            -appname APPNAME      Name of the application.
            -apppath APPPATH      Path to installed application binary.
            -datatype DATATYPE    URN of the NDEF message type to match.
            -match MATCHSTRING    Platform specific match string.

        The -datatype and -match options are mutually exclusive.

        Available templates: maemo6
    \endcode

    A typical invocation of the \c ndefhandlergen tool for Maemo6 target:

    \code
        ndefhandlergen -template maemo6 -appname myapplication -apppath /usr/bin/myapplication -datatype urn:nfc:ext:com.example:f
    \endcode

    Once the application has been registered as an NDEF message handler, the application only needs
    to call the registerNdefMessageHandler() function:

    \code
        QNearFieldManager *manager = new QNearFieldManager;
        manager->registerNdefMessageHandler(this,
                                            SLOT(handleNdefMessage(QNdefMessage,QNearFieldTarget)));
    \endcode

    \code
        <customproperty key="datatype">urn:nfc:wkt:U</customproperty>
    \endcode

*/

/*!
    \enum QNearFieldManager::TargetAccessMode

    This enum describes the different access modes an application can have.

    \value NoTargetAccess           The application cannot access NFC capabilities.
    \value NdefReadTargetAccess     The application can read NDEF messages from targets by calling
                                    QNearFieldTarget::readNdefMessages().
    \value NdefWriteTargetAccess    The application can write NDEF messages to targets by calling
                                    QNearFieldTarget::writeNdefMessages().
    \value TagTypeSpecificTargetAccess  The application can access targets using raw commands by
                                        calling QNearFieldTarget::sendCommand().
*/

/*!
    \fn void QNearFieldManager::targetDetected(QNearFieldTarget *target)

    This signal is emitted whenever a target is detected. The \a target parameter represents the
    detected target.

    This signal will be emitted for all detected targets.

    QNearFieldManager maintains ownership of \a target, however, it will not be destroyed until
    the QNearFieldManager destructor is called. Ownership may be transferred by calling
    setParent().

    Do not delete \a target from the slot connected to this signal, instead call deleteLater().

    \note that if \a target is deleted before it moves out of proximity the targetLost() signal
    will not be emitted.

    \sa targetLost()
*/

/*!
    \fn void QNearFieldManager::targetLost(QNearFieldTarget *target)

    This signal is emitted whenever a target moves out of proximity. The \a target parameter
    represents the lost target.

    Do not delete \a target from the slot connected to this signal, instead use deleteLater().

    \sa QNearFieldTarget::disconnected()
*/

/*!
    \fn void QNearFieldManager::transactionDetected(const QByteArray &applicationIdentifier)

    This signal is emitted when ever a transaction is performed with the application identified by
    \a applicationIdentifier.

    The \a applicationIdentifier is a byte array of up to 16 bytes as defined by ISO 7816-4 and
    uniquely identifies the application and application vendor that was involved in the
    transaction.
*/

/*!
    Constructs a new near field manager with \a parent.
*/
QNearFieldManager::QNearFieldManager(QObject *parent)
:   QObject(parent), d_ptr(new QNearFieldManagerPrivateImpl)
{
    connect(d_ptr, SIGNAL(targetDetected(QNearFieldTarget*)),
            this, SIGNAL(targetDetected(QNearFieldTarget*)));
    connect(d_ptr, SIGNAL(targetLost(QNearFieldTarget*)),
            this, SIGNAL(targetLost(QNearFieldTarget*)));
}

/*!
    \internal

    Constructs a new near field manager with the specified \a backend and with \a parent.

    \note: This constructor is only enable for internal builds and is used for testing the
    simulator backend.
*/
QNearFieldManager::QNearFieldManager(QNearFieldManagerPrivate *backend, QObject *parent)
:   QObject(parent), d_ptr(backend)
{
    connect(d_ptr, SIGNAL(targetDetected(QNearFieldTarget*)),
            this, SIGNAL(targetDetected(QNearFieldTarget*)));
    connect(d_ptr, SIGNAL(targetLost(QNearFieldTarget*)),
            this, SIGNAL(targetLost(QNearFieldTarget*)));
}

/*!
    Destroys the near field manager.
*/
QNearFieldManager::~QNearFieldManager()
{
    delete d_ptr;
}

/*!
    Returns true if NFC functionality is available; otherwise returns false.
*/
bool QNearFieldManager::isAvailable() const
{
    Q_D(const QNearFieldManager);

    return d->isAvailable();
}

/*!
    Starts detecting targets of type \a targetTypes. Returns true if target detection is
    successfully started; otherwise returns false.

    Causes the targetDetected() signal to be emitted when a target with a type in \a targetTypes is
    within proximity. If \a targetTypes is empty targets of all types will be detected.

    \sa stopTargetDetection()
*/
bool QNearFieldManager::startTargetDetection(const QList<QNearFieldTarget::Type> &targetTypes)
{
    Q_D(QNearFieldManager);

    if (targetTypes.isEmpty())
        return d->startTargetDetection(QList<QNearFieldTarget::Type>() << QNearFieldTarget::AnyTarget);
    else
        return d->startTargetDetection(targetTypes);
}

/*!
    \overload

    Starts detecting targets of type \a targetType. Returns true if target detection is
    successfully started; otherwise returns false. Causes the targetDetected() signal to be emitted
    when a target with the type \a targetType is within proximity.
*/
bool QNearFieldManager::startTargetDetection(QNearFieldTarget::Type targetType)
{
    return startTargetDetection(QList<QNearFieldTarget::Type>() << targetType);
}

/*!
    Stops detecting targets.  The targetDetected() signal will no longer be emitted until another
    call to startTargetDetection() is made.
*/
void QNearFieldManager::stopTargetDetection()
{
    Q_D(QNearFieldManager);

    d->stopTargetDetection();
}

static QMetaMethod methodForSignature(QObject *object, const char *method)
{
    QByteArray normalizedMethod = QMetaObject::normalizedSignature(method);

    if (!QMetaObject::checkConnectArgs(SIGNAL(targetDetected(QNdefMessage,QNearFieldTarget*)),
                                       normalizedMethod)) {
        qWarning("Signatures do not match: %s:%d\n", __FILE__, __LINE__);
        return QMetaMethod();
    }

    quint8 memcode = (normalizedMethod.at(0) - '0') & 0x03;
    normalizedMethod = normalizedMethod.mid(1);

    int index;
    switch (memcode) {
    case QSLOT_CODE:
        index = object->metaObject()->indexOfSlot(normalizedMethod.constData());
        break;
    case QSIGNAL_CODE:
        index = object->metaObject()->indexOfSignal(normalizedMethod.constData());
        break;
    case QMETHOD_CODE:
        index = object->metaObject()->indexOfMethod(normalizedMethod.constData());
        break;
    default:
        index = -1;
    }

    if (index == -1)
        return QMetaMethod();

    return object->metaObject()->method(index);
}

/*!
    Registers \a object to receive notifications on \a method when a tag has been detected and has
    an NDEF record that matches \a typeNameFormat and \a type.  The \a method on \a object should
    have the prototype
    'void targetDetected(const QNdefMessage &message, QNearFieldTarget *target)'.

    Returns an identifier, which can be used to unregister the handler, on success; otherwise
    returns -1.

    \note The \e target parameter of \a method may not be available on all platforms, in which case
    \e target will be 0.
*/

int QNearFieldManager::registerNdefMessageHandler(QNdefRecord::TypeNameFormat typeNameFormat,
                                                  const QByteArray &type,
                                                  QObject *object, const char *method)
{
    QMetaMethod metaMethod = methodForSignature(object, method);
    if (!metaMethod.enclosingMetaObject())
        return -1;

    QNdefFilter filter;
    filter.appendRecord(typeNameFormat, type);

    Q_D(QNearFieldManager);

    return d->registerNdefMessageHandler(filter, object, metaMethod);
}

/*!
    \fn int QNearFieldManager::registerNdefMessageHandler(QObject *object, const char *method)

    Registers \a object to receive notifications on \a method when a tag has been detected and has
    an NDEF message that matches a pre-registered message format. The \a method on \a object should
    have the prototype
    'void targetDetected(const QNdefMessage &message, QNearFieldTarget *target)'.

    Returns an identifier, which can be used to unregister the handler, on success; otherwise
    returns -1.

    This function is used to register a QNearFieldManager instance to receive notifications when a
    NDEF message matching a pre-registered message format is received. See the section on
    \l {Automatically launching NDEF message handlers}.

    \note The \e target parameter of \a method may not be available on all platforms, in which case
    \e target will be 0.
*/
int QNearFieldManager::registerNdefMessageHandler(QObject *object, const char *method)
{
    QMetaMethod metaMethod = methodForSignature(object, method);
    if (!metaMethod.enclosingMetaObject())
        return -1;

    Q_D(QNearFieldManager);

    return d->registerNdefMessageHandler(object, metaMethod);
}

/*!
    Registers \a object to receive notifications on \a method when a tag has been detected and has
    an NDEF message that matches \a filter is detected. The \a method on \a object should have the
    prototype 'void targetDetected(const QNdefMessage &message, QNearFieldTarget *target)'.

    Returns an identifier, which can be used to unregister the handler, on success; otherwise
    returns -1.

    \note The \e target parameter of \a method may not be available on all platforms, in which case
    \e target will be 0.
*/
int QNearFieldManager::registerNdefMessageHandler(const QNdefFilter &filter,
                                                  QObject *object, const char *method)
{
    QMetaMethod metaMethod = methodForSignature(object, method);
    if (!metaMethod.enclosingMetaObject())
        return -1;

    Q_D(QNearFieldManager);

    return d->registerNdefMessageHandler(filter, object, metaMethod);
}

/*!
    Unregisters the target detect handler identified by \a handlerId.

    Returns true on success; otherwise returns false.
*/
bool QNearFieldManager::unregisterNdefMessageHandler(int handlerId)
{
    Q_D(QNearFieldManager);

    return d->unregisterNdefMessageHandler(handlerId);
}

/*!
    Sets the requested target access modes to \a accessModes.
*/
void QNearFieldManager::setTargetAccessModes(TargetAccessModes accessModes)
{
    Q_D(QNearFieldManager);

    TargetAccessModes removedModes = ~accessModes & d->m_requestedModes;
    if (removedModes)
        d->releaseAccess(removedModes);

    TargetAccessModes newModes = accessModes & ~d->m_requestedModes;
    if (newModes)
        d->requestAccess(newModes);
}

/*!
    Returns current requested target access modes.
*/
QNearFieldManager::TargetAccessModes QNearFieldManager::targetAccessModes() const
{
    Q_D(const QNearFieldManager);

    return d->m_requestedModes;
}

#include "moc_qnearfieldmanager.cpp"
#include "moc_qnearfieldmanager_p.cpp"

QTNFC_END_NAMESPACE