source: trunk/src/dbus/qdbusservicewatcher.cpp@ 971

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#include "qdbusservicewatcher.h"
#include "qdbusconnection.h"
#include "qdbus_symbols_p.h"

#include <QStringList>

#include <private/qobject_p.h>

#ifndef QT_NO_DBUS

QT_BEGIN_NAMESPACE

Q_GLOBAL_STATIC_WITH_ARGS(QString, busService, (QLatin1String(DBUS_SERVICE_DBUS)))
Q_GLOBAL_STATIC_WITH_ARGS(QString, busInterface, (QLatin1String(DBUS_INTERFACE_DBUS)))
Q_GLOBAL_STATIC_WITH_ARGS(QString, signalName, (QLatin1String("NameOwnerChanged")))

class QDBusServiceWatcherPrivate: public QObjectPrivate
{
    Q_DECLARE_PUBLIC(QDBusServiceWatcher)
public:
    QDBusServiceWatcherPrivate(const QDBusConnection &c, QDBusServiceWatcher::WatchMode wm)
        : connection(c), watchMode(wm)
    {
    }

    QStringList servicesWatched;
    QDBusConnection connection;
    QDBusServiceWatcher::WatchMode watchMode;

    void _q_serviceOwnerChanged(const QString &, const QString &, const QString &);
    void setConnection(const QStringList &services, const QDBusConnection &c, QDBusServiceWatcher::WatchMode watchMode);

    QStringList matchArgsForService(const QString &service);
    void addService(const QString &service);
    void removeService(const QString &service);
};

void QDBusServiceWatcherPrivate::_q_serviceOwnerChanged(const QString &service, const QString &oldOwner, const QString &newOwner)
{
    Q_Q(QDBusServiceWatcher);
    emit q->serviceOwnerChanged(service, oldOwner, newOwner);
    if (oldOwner.isEmpty())
        emit q->serviceRegistered(service);
    else if (newOwner.isEmpty())
        emit q->serviceUnregistered(service);
}

void QDBusServiceWatcherPrivate::setConnection(const QStringList &s, const QDBusConnection &c, QDBusServiceWatcher::WatchMode wm)
{
    if (connection.isConnected()) {
        // remove older rules
        foreach (const QString &s, servicesWatched)
            removeService(s);
    }

    connection = c;
    watchMode = wm;
    servicesWatched = s;

    if (connection.isConnected()) {
        // add new rules
        foreach (const QString &s, servicesWatched)
            addService(s);
    }
}

QStringList QDBusServiceWatcherPrivate::matchArgsForService(const QString &service)
{
    QStringList matchArgs;
    matchArgs << service;

    switch (watchMode) {
    case QDBusServiceWatcher::WatchForOwnerChange:
        break;

    case QDBusServiceWatcher::WatchForRegistration:
        matchArgs << QString::fromLatin1("", 0);
        break;

    case QDBusServiceWatcher::WatchForUnregistration:
        matchArgs << QString() << QString::fromLatin1("", 0);
        break;
    }
    return matchArgs;
}

void QDBusServiceWatcherPrivate::addService(const QString &service)
{
    QStringList matchArgs = matchArgsForService(service);
    connection.connect(*busService(), QString(), *busInterface(), *signalName(),
                       matchArgs, QString(), q_func(),
                       SLOT(_q_serviceOwnerChanged(QString,QString,QString)));
}

void QDBusServiceWatcherPrivate::removeService(const QString &service)
{
    QStringList matchArgs = matchArgsForService(service);
    connection.disconnect(*busService(), QString(), *busInterface(), *signalName(),
                          matchArgs, QString(), q_func(),
                          SLOT(_q_serviceOwnerChanged(QString,QString,QString)));
}

/*!
    \class QDBusServiceWatcher
    \since 4.6
    \inmodule QtDBus

    \brief The QDBusServiceWatcher class allows the user to watch for a bus service change.

    A QDBusServiceWatcher object can be used to notify the application about
    an ownership change of a service name on the bus. It has three watch
    modes:

    \list
      \o Watching for service registration only.
      \o Watching for service unregistration only.
      \o Watching for any kind of service ownership change (the default mode).
    \endlist

    Besides being created or deleted, services may change owners without a
    unregister/register operation happening. So the serviceRegistered()
    and serviceUnregistered() signals may not be emitted if that
    happens.

    This class is more efficient than using the
    QDBusConnectionInterface::serviceOwnerChanged() signal because it allows
    one to receive only the signals for which the class is interested in.

    \sa QDBusConnection
*/

/*!
    \enum QDBusServiceWatcher::WatchModeFlag

    QDBusServiceWatcher supports three different watch modes, which are configured by this flag:

    \value WatchForRegistration watch for service registration only, ignoring
    any signals related to other service ownership change.

    \value WatchForUnregistration watch for service unregistration only,
    ignoring any signals related to other service ownership change.

    \value WatchForOwnerChange watch for any kind of service ownership
    change.
*/

/*!
    \property QDBusServiceWatcher::watchMode

    The \c watchMode property holds the current watch mode for this
    QDBusServiceWatcher object. The default value for this property is
    QDBusServiceWatcher::WatchForOwnershipChange.
*/

/*!
    \property QDBusServiceWatcher::watchedServices

    The \c servicesWatched property holds the list of services watched.

    Note that modifying this list with setServicesWatched() is an expensive
    operation. If you can, prefer to change it by way of addWatchedService()
    and removeWatchedService().
*/

/*!
    \fn void QDBusServiceWatcher::serviceRegistered(const QString &serviceName)

    This signal is emitted whenever this object detects that the service \a
    serviceName became available on the bus.

    \sa serviceUnregistered(), serviceOwnerChanged()
*/

/*!
    \fn void QDBusServiceWatcher::serviceUnregistered(const QString &serviceName)

    This signal is emitted whenever this object detects that the service \a
    serviceName was unregistered from the bus and is no longer available.

    \sa serviceRegistered(), serviceOwnerChanged()
*/

/*!
    \fn void QDBusServiceWatcher::serviceOwnerChanged(const QString &serviceName, const QString &oldOwner, const QString &newOwner)

    This signal is emitted whenever this object detects that there was a
    service ownership change relating to the \a serviceName service. The \a
    oldOwner parameter contains the old owner name and \a newOwner is the new
    owner. Both \a oldOwner and \a newOwner are unique connection names.

    Note that this signal is also emitted whenever the \a serviceName service
    was registered or unregistered. If it was registered, \a oldOwner will
    contain an empty string, whereas if it was unregistered, \a newOwner will
    contain an empty string.

    If you need only to find out if the service is registered or unregistered
    only, without being notified that the ownership changed, consider using
    the specific modes for those operations. This class is more efficient if
    you use the more specific modes.