qdbusconnection.cpp

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**
** Copyright (C) 2014 Digia Plc and/or its subsidiary(-ies).
** Contact: http://www.qt-project.org/legal
**
** This file is part of the QtDBus module of the Qt Toolkit.
**
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** packaging of this file.  Please review the following information to
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#include <qdebug.h>
#include <qcoreapplication.h>
#include <qstringlist.h>
#include <qthread.h>

#include "qdbusconnection.h"
#include "qdbusconnectioninterface.h"
#include "qdbuserror.h"
#include "qdbusmessage.h"
#include "qdbusmessage_p.h"
#include "qdbusconnection_p.h"
#include "qdbusinterface_p.h"
#include "qdbusutil_p.h"
#include "qdbusconnectionmanager_p.h"
#include "qdbuspendingcall_p.h"

#include "qdbusthreaddebug_p.h"

#ifndef QT_NO_DBUS

QT_BEGIN_NAMESPACE

Q_GLOBAL_STATIC(QDBusConnectionManager, _q_manager)

QDBusConnectionPrivate *QDBusConnectionManager::sender() const
{
    QMutexLocker locker(&senderMutex);
    return connection(senderName);
}

void QDBusConnectionManager::setSender(const QDBusConnectionPrivate *s)
{
    QMutexLocker locker(&senderMutex);
    senderName = (s ? s->name : QString());
}

QDBusConnectionPrivate *QDBusConnectionManager::connection(const QString &name) const
{
    return connectionHash.value(name, 0);
}

void QDBusConnectionManager::removeConnection(const QString &name)
{
    QDBusConnectionPrivate *d = 0;
    d = connectionHash.take(name);
    if (d && !d->ref.deref())
        d->deleteYourself();

    // Static objects may be keeping the connection open.
    // However, it is harmless to have outstanding references to a connection that is
    // closing as long as those references will be soon dropped without being used.

    // ### Output a warning if connections are being used after they have been removed.
}

QDBusConnectionManager::~QDBusConnectionManager()
{
    for (QHash<QString, QDBusConnectionPrivate *>::const_iterator it = connectionHash.constBegin();
         it != connectionHash.constEnd(); ++it) {
        QDBusConnectionPrivate *d = it.value();
        if (!d->ref.deref())
            d->deleteYourself();
        else
            d->closeConnection();
    }
    connectionHash.clear();
}

QDBusConnectionManager* QDBusConnectionManager::instance()
{
    return _q_manager();
}

Q_DBUS_EXPORT void qDBusBindToApplication();
void qDBusBindToApplication()
{
}

void QDBusConnectionManager::setConnection(const QString &name, QDBusConnectionPrivate *c)
{
    connectionHash[name] = c;
    c->name = name;
}

QDBusConnection::QDBusConnection(const QString &name)
{
    if (name.isEmpty()) {
        d = 0;
    } else {
        QMutexLocker locker(&_q_manager()->mutex);
        d = _q_manager()->connection(name);
        if (d)
            d->ref.ref();
    }
}

QDBusConnection::QDBusConnection(const QDBusConnection &other)
{
    d = other.d;
    if (d)
        d->ref.ref();
}

QDBusConnection::QDBusConnection(QDBusConnectionPrivate *dd)
{
    d = dd;
    if (d)
        d->ref.ref();
}

QDBusConnection::~QDBusConnection()
{
    if (d && !d->ref.deref())
        d->deleteYourself();
}

QDBusConnection &QDBusConnection::operator=(const QDBusConnection &other)
{
    if (other.d)
        other.d->ref.ref();
    if (d && !d->ref.deref())
        d->deleteYourself();
    d = other.d;
    return *this;
}

QDBusConnection QDBusConnection::connectToBus(BusType type, const QString &name)
{
//    Q_ASSERT_X(QCoreApplication::instance(), "QDBusConnection::addConnection",
//               "Cannot create connection without a Q[Core]Application instance");
    if (!qdbus_loadLibDBus()) {
        QDBusConnectionPrivate *d = 0;
        return QDBusConnection(d);
    }

    QMutexLocker locker(&_q_manager()->mutex);

    QDBusConnectionPrivate *d = _q_manager()->connection(name);
    if (d || name.isEmpty())
        return QDBusConnection(d);

    d = new QDBusConnectionPrivate;
    DBusConnection *c = 0;
    QDBusErrorInternal error;
    switch (type) {
        case SystemBus:
            c = q_dbus_bus_get_private(DBUS_BUS_SYSTEM, error);
            break;
        case SessionBus:
            c = q_dbus_bus_get_private(DBUS_BUS_SESSION, error);
            break;
        case ActivationBus:
            c = q_dbus_bus_get_private(DBUS_BUS_STARTER, error);
            break;
    }
    d->setConnection(c, error); //setConnection does the error handling for us

    _q_manager()->setConnection(name, d);

    QDBusConnection retval(d);

    // create the bus service
    // will lock in QDBusConnectionPrivate::connectRelay()
    d->setBusService(retval);

    return retval;
}

QDBusConnection QDBusConnection::connectToBus(const QString &address,
                                              const QString &name)
{
//    Q_ASSERT_X(QCoreApplication::instance(), "QDBusConnection::addConnection",
//               "Cannot create connection without a Q[Core]Application instance");
    if (!qdbus_loadLibDBus()) {
        QDBusConnectionPrivate *d = 0;
        return QDBusConnection(d);
    }

    QMutexLocker locker(&_q_manager()->mutex);

    QDBusConnectionPrivate *d = _q_manager()->connection(name);
    if (d || name.isEmpty())
        return QDBusConnection(d);

    d = new QDBusConnectionPrivate;
    // setConnection does the error handling for us
    QDBusErrorInternal error;
    DBusConnection *c = q_dbus_connection_open_private(address.toUtf8().constData(), error);
    if (c) {
        if (!q_dbus_bus_register(c, error)) {
            q_dbus_connection_unref(c);
            c = 0;
        }
    }
    d->setConnection(c, error);
    _q_manager()->setConnection(name, d);

    QDBusConnection retval(d);

    // create the bus service
    // will lock in QDBusConnectionPrivate::connectRelay()
    d->setBusService(retval);

    return retval;
}
QDBusConnection QDBusConnection::connectToPeer(const QString &address,
                                               const QString &name)
{
//    Q_ASSERT_X(QCoreApplication::instance(), "QDBusConnection::addConnection",
//               "Cannot create connection without a Q[Core]Application instance");
    if (!qdbus_loadLibDBus()) {
        QDBusConnectionPrivate *d = 0;
        return QDBusConnection(d);
    }

    QMutexLocker locker(&_q_manager()->mutex);

    QDBusConnectionPrivate *d = _q_manager()->connection(name);
    if (d || name.isEmpty())
        return QDBusConnection(d);

    d = new QDBusConnectionPrivate;
    // setPeer does the error handling for us
    QDBusErrorInternal error;
    DBusConnection *c = q_dbus_connection_open_private(address.toUtf8().constData(), error);

    d->setPeer(c, error);
    _q_manager()->setConnection(name, d);

    QDBusConnection retval(d);

    return retval;
}

void QDBusConnection::disconnectFromBus(const QString &name)
{
    if (_q_manager()) {
        QMutexLocker locker(&_q_manager()->mutex);
        QDBusConnectionPrivate *d = _q_manager()->connection(name);
        if (d && d->mode != QDBusConnectionPrivate::ClientMode)
            return;
        _q_manager()->removeConnection(name);
    }
}

void QDBusConnection::disconnectFromPeer(const QString &name)
{
    if (_q_manager()) {
        QMutexLocker locker(&_q_manager()->mutex);
        QDBusConnectionPrivate *d = _q_manager()->connection(name);
        if (d && d->mode != QDBusConnectionPrivate::PeerMode)
            return;
        _q_manager()->removeConnection(name);
    }
}

bool QDBusConnection::send(const QDBusMessage &message) const
{
    if (!d || !d->connection) {
        QDBusError err = QDBusError(QDBusError::Disconnected,
                                    QLatin1String("Not connected to D-BUS server"));
        if (d)
            d->lastError = err;
        return false;
    }
    return d->send(message) != 0;
}

bool QDBusConnection::callWithCallback(const QDBusMessage &message, QObject *receiver,
                                       const char *returnMethod, const char *errorMethod,
                                       int timeout) const
{
    if (!d || !d->connection) {
        QDBusError err = QDBusError(QDBusError::Disconnected,
                                    QLatin1String("Not connected to D-BUS server"));
        if (d)
            d->lastError = err;
        return false;
    }
    return d->sendWithReplyAsync(message, receiver, returnMethod, errorMethod, timeout) != 0;
}

bool QDBusConnection::callWithCallback(const QDBusMessage &message, QObject *receiver,
                                       const char *returnMethod, int timeout) const
{
    return callWithCallback(message, receiver, returnMethod, 0, timeout);
}

QDBusMessage QDBusConnection::call(const QDBusMessage &message, QDBus::CallMode mode, int timeout) const
{
    if (!d || !d->connection) {
        QDBusError err = QDBusError(QDBusError::Disconnected,
                                    QLatin1String("Not connected to D-Bus server"));
        if (d)
            d->lastError = err;

        return QDBusMessage::createError(err);
    }

    if (mode != QDBus::NoBlock)
        return d->sendWithReply(message, mode, timeout);

    d->send(message);
    QDBusMessage retval;
    retval << QVariant(); // add one argument (to avoid .at(0) problems)
    return retval;
}

QDBusPendingCall QDBusConnection::asyncCall(const QDBusMessage &message, int timeout) const
{
    if (!d || !d->connection) {
        return QDBusPendingCall(0); // null pointer -> disconnected
    }

    QDBusPendingCallPrivate *priv = d->sendWithReplyAsync(message, 0, 0, 0, timeout);
    return QDBusPendingCall(priv);
}

bool QDBusConnection::connect(const QString &service, const QString &path, const QString& interface,
                              const QString &name, QObject *receiver, const char *slot)
{
    return connect(service, path, interface, name, QStringList(), QString(), receiver, slot);
}

bool QDBusConnection::connect(const QString &service, const QString &path, const QString& interface,
                              const QString &name, const QString &signature,
                              QObject *receiver, const char *slot)
{
    return connect(service, path, interface, name, QStringList(), signature, receiver, slot);
}

bool QDBusConnection::connect(const QString &service, const QString &path, const QString& interface,
                              const QString &name, const QStringList &argumentMatch, const QString &signature,
                              QObject *receiver, const char *slot)
{

    if (!receiver || !slot || !d || !d->connection)
        return false;
    if (interface.isEmpty() && name.isEmpty())
        return false;
    if (!interface.isEmpty() && !QDBusUtil::isValidInterfaceName(interface)) {
#ifndef QT_NO_DEBUG
        qWarning("QDBusConnection::connect: interface name '%s' is not valid", interface.toLatin1().constData());
#endif
        return false;
    }
    if (!service.isEmpty() && !QDBusUtil::isValidBusName(service)) {
#ifndef QT_NO_DEBUG
        qWarning("QDBusConnection::connect: service name '%s' is not valid", service.toLatin1().constData());
#endif
        return false;
    }
    if (!path.isEmpty() && !QDBusUtil::isValidObjectPath(path)) {
#ifndef QT_NO_DEBUG
        qWarning("QDBusConnection::connect: object path '%s' is not valid", path.toLatin1().constData());
#endif
        return false;
    }

    QDBusWriteLocker locker(ConnectAction, d);
    return d->connectSignal(service, path, interface, name, argumentMatch, signature, receiver, slot);
}

bool QDBusConnection::disconnect(const QString &service, const QString &path, const QString &interface,
                                 const QString &name, QObject *receiver, const char *slot)
{
    return disconnect(service, path, interface, name, QStringList(), QString(), receiver, slot);
}

bool QDBusConnection::disconnect(const QString &service, const QString &path, const QString& interface,
                                 const QString &name, const QString &signature,
                                 QObject *receiver, const char *slot)
{
    return disconnect(service, path, interface, name, QStringList(), signature, receiver, slot);
}

bool QDBusConnection::disconnect(const QString &service, const QString &path, const QString& interface,
                                 const QString &name, const QStringList &argumentMatch, const QString &signature,
                                 QObject *receiver, const char *slot)
{
    if (!receiver || !slot || !d || !d->connection)
        return false;
    if (!interface.isEmpty() && !QDBusUtil::isValidInterfaceName(interface))
        return false;
    if (interface.isEmpty() && name.isEmpty())
        return false;

    QDBusWriteLocker locker(DisconnectAction, d);
    return d->disconnectSignal(service, path, interface, name, argumentMatch, signature, receiver, slot);
}

bool QDBusConnection::registerObject(const QString &path, QObject *object, RegisterOptions options)
{
    Q_ASSERT_X(QDBusUtil::isValidObjectPath(path), "QDBusConnection::registerObject",
               "Invalid object path given");
    if (!d || !d->connection || !object || !options || !QDBusUtil::isValidObjectPath(path))
        return false;

    QStringList pathComponents = path.split(QLatin1Char('/'));
    if (pathComponents.last().isEmpty())
        pathComponents.removeLast();
    QDBusWriteLocker locker(RegisterObjectAction, d);

    // lower-bound search for where this object should enter in the tree
    QDBusConnectionPrivate::ObjectTreeNode *node = &d->rootNode;
    int i = 1;
    while (node) {
        if (pathComponents.count() == i) {
            // this node exists
            // consider it free if there's no object here and the user is not trying to
            // replace the object sub-tree
            if (node->obj)
                return false;

            if (options & QDBusConnectionPrivate::VirtualObject) {
                // technically the check for children needs to go even deeper
                if (options & SubPath) {
                    foreach (const QDBusConnectionPrivate::ObjectTreeNode &child, node->children) {
                        if (child.obj)
                            return false;
                    }
                }
            } else {
                if ((options & ExportChildObjects && !node->children.isEmpty()))
                    return false;
            }
            // we can add the object here
            node->obj = object;
            node->flags = options;

            d->registerObject(node);
            //qDebug("REGISTERED FOR %s", path.toLocal8Bit().constData());
            return true;
        }

        // if a virtual object occupies this path, return false
        if (node->obj && (node->flags & QDBusConnectionPrivate::VirtualObject) && (node->flags & QDBusConnection::SubPath)) {
            qDebug("Cannot register object at %s because QDBusVirtualObject handles all sub-paths.",
                   qPrintable(path));
            return false;
        }

        // find the position where we'd insert the node
        QDBusConnectionPrivate::ObjectTreeNode::DataList::Iterator it =
            qLowerBound(node->children.begin(), node->children.end(), pathComponents.at(i));
        if (it != node->children.end() && it->name == pathComponents.at(i)) {
            // match: this node exists
            node = it;

            // are we allowed to go deeper?
            if (node->flags & ExportChildObjects) {
                // we're not
                qDebug("Cannot register object at %s because %s exports its own child objects",
                       qPrintable(path), qPrintable(pathComponents.at(i)));
                return false;
            }
        } else {
            // add entry
            node = node->children.insert(it, pathComponents.at(i));
        }

        // iterate
        ++i;
    }

    Q_ASSERT_X(false, "QDBusConnection::registerObject", "The impossible happened");
    return false;
}

bool QDBusConnection::registerVirtualObject(const QString &path, QDBusVirtualObject *treeNode,
                      VirtualObjectRegisterOption options)
{
    int opts = options | QDBusConnectionPrivate::VirtualObject;
    return registerObject(path, (QObject*) treeNode, (RegisterOptions) opts);
}

void QDBusConnection::unregisterObject(const QString &path, UnregisterMode mode)
{
    if (!d || !d->connection || !QDBusUtil::isValidObjectPath(path))
        return;

    QStringList pathComponents = path.split(QLatin1Char('/'));
    QDBusWriteLocker locker(UnregisterObjectAction, d);
    QDBusConnectionPrivate::ObjectTreeNode *node = &d->rootNode;
    int i = 1;

    // find the object
    while (node) {
        if (pathComponents.count() == i || !path.compare(QLatin1String("/"))) {
            // found it
            node->obj = 0;
            node->flags = 0;

            if (mode == UnregisterTree) {
                // clear the sub-tree as well
                node->children.clear();  // can't disconnect the objects because we really don't know if they can
                                // be found somewhere else in the path too
            }

            return;
        }

        QDBusConnectionPrivate::ObjectTreeNode::DataList::Iterator it =
            qLowerBound(node->children.begin(), node->children.end(), pathComponents.at(i));
        if (it == node->children.end() || it->name != pathComponents.at(i))
            break;              // node not found

        node = it;
        ++i;
    }
}

QObject *QDBusConnection::objectRegisteredAt(const QString &path) const
{
    Q_ASSERT_X(QDBusUtil::isValidObjectPath(path), "QDBusConnection::registeredObject",
               "Invalid object path given");
    if (!d || !d->connection || !QDBusUtil::isValidObjectPath(path))
        return 0;

    QStringList pathComponents = path.split(QLatin1Char('/'));
    if (pathComponents.last().isEmpty())
        pathComponents.removeLast();

    // lower-bound search for where this object should enter in the tree
    QDBusReadLocker lock(ObjectRegisteredAtAction, d);
    const QDBusConnectionPrivate::ObjectTreeNode *node = &d->rootNode;

    int i = 1;
    while (node) {
        if (pathComponents.count() == i)
            return node->obj;
        if ((node->flags & QDBusConnectionPrivate::VirtualObject) && (node->flags & QDBusConnection::SubPath))
            return node->obj;

        QDBusConnectionPrivate::ObjectTreeNode::DataList::ConstIterator it =
            qLowerBound(node->children.constBegin(), node->children.constEnd(), pathComponents.at(i));
        if (it == node->children.constEnd() || it->name != pathComponents.at(i))
            break;              // node not found

        node = it;
        ++i;
    }
    return 0;
}



QDBusConnectionInterface *QDBusConnection::interface() const
{
    if (!d)
        return 0;
    return d->busService;
}

void *QDBusConnection::internalPointer() const
{
    return d ? d->connection : 0;
}

bool QDBusConnection::isConnected() const
{
    return d && d->connection && q_dbus_connection_get_is_connected(d->connection);
}

QDBusError QDBusConnection::lastError() const
{
    return d ? d->lastError : QDBusError();
}

QString QDBusConnection::baseService() const
{
    return d ? d->baseService : QString();
}

QString QDBusConnection::name() const
{
    return d ? d->name : QString();
}

QDBusConnection::ConnectionCapabilities QDBusConnection::connectionCapabilities() const
{
    return d ? d->capabilities : ConnectionCapabilities(0);
}

bool QDBusConnection::registerService(const QString &serviceName)
{
    if (interface() && interface()->registerService(serviceName)) {
        if (d) d->registerService(serviceName);
        return true;
    }
    return false;
}

bool QDBusConnection::unregisterService(const QString &serviceName)
{
    if (interface()->unregisterService(serviceName)) {
        if (d) d->unregisterService(serviceName);
        return true;
    }
    return false;
}

static const char _q_sessionBusName[] = "qt_default_session_bus";
static const char _q_systemBusName[] = "qt_default_system_bus";

class QDBusDefaultConnection: public QDBusConnection
{
    const char *ownName;
public:
    inline QDBusDefaultConnection(BusType type, const char *name)
        : QDBusConnection(connectToBus(type, QString::fromLatin1(name))), ownName(name)
    {
        // make sure this connection is running on the main thread
        QCoreApplication *instance = QCoreApplication::instance();
        if (!instance) {
            qWarning("QDBusConnection: %s D-Bus connection created before QCoreApplication. Application may misbehave.",
                     type == SessionBus ? "session" : type == SystemBus ? "system" : "generic");
        } else if (QDBusConnectionPrivate::d(*this)) {
            QDBusConnectionPrivate::d(*this)->moveToThread(instance->thread());
        }
    }

    inline ~QDBusDefaultConnection()
    { disconnectFromBus(QString::fromLatin1(ownName)); }
};

Q_GLOBAL_STATIC_WITH_ARGS(QDBusDefaultConnection, _q_sessionBus,
                          (QDBusConnection::SessionBus, _q_sessionBusName))
Q_GLOBAL_STATIC_WITH_ARGS(QDBusDefaultConnection, _q_systemBus,
                          (QDBusConnection::SystemBus, _q_systemBusName))

QDBusConnection QDBusConnection::sessionBus()
{
    return *_q_sessionBus();
}

QDBusConnection QDBusConnection::systemBus()
{
    return *_q_systemBus();
}

QDBusConnection QDBusConnection::sender()
{
    return QDBusConnection(_q_manager()->sender());
}

void QDBusConnectionPrivate::setSender(const QDBusConnectionPrivate *s)
{
    _q_manager()->setSender(s);
}

void QDBusConnectionPrivate::setBusService(const QDBusConnection &connection)
{
    busService = new QDBusConnectionInterface(connection, this);
    ref.deref(); // busService has increased the refcounting to us
                 // avoid cyclic refcounting

    QObject::connect(this, SIGNAL(callWithCallbackFailed(QDBusError,QDBusMessage)),
                     busService, SIGNAL(callWithCallbackFailed(QDBusError,QDBusMessage)),
                     Qt::QueuedConnection);
}

QByteArray QDBusConnection::localMachineId()
{
    char *dbus_machine_id = q_dbus_get_local_machine_id();
    QByteArray result = dbus_machine_id;
    q_dbus_free(dbus_machine_id);
    return result;
}

QT_END_NAMESPACE

#endif // QT_NO_DBUS