How to enable qt dbus marshaling with cmake?

Question

I am trying to create a very simple example of dbus marshaling, using cmake as the build system. Complete code is found at the end of the question.

The problem I am facing, is how to include the header defining structures for the messages in the generated adapter. The qdbusxml2cpp tool allows passing required includes, but cmake's qt4_add_dbus_adaptor macro doesn't seems to accept more then include header.

The error is :

chatadaptor.moc:59:72: error: invalid use of incomplete type ‘struct MessageData’

I know I could manually add the include, but I want cmake to do it for me.

So, how can I enable dbus marshaling combined with cmake?

---

I am not sure if it matters, but I haven't found a way to have dbus marshaling even with qmake.

---

CMakeLists.txt :

CMAKE_MINIMUM_REQUIRED( VERSION 2.6 )


PROJECT( CustomDbusTypes )



FIND_PACKAGE( Qt4 COMPONENTS QtCore QtGui QtDBUS REQUIRED )
include(${QT_USE_FILE})


# Find includes in corresponding build directories
set(CMAKE_INCLUDE_CURRENT_DIR ON)



SET( CustomDbusTypes_SRC
        main.cpp 
        MyMessages.cpp
        DbusMessagesReceiver.cpp
    )

SET( CustomDbusTypes_HEADERS
        MyMessages.hpp
        DbusMessagesReceiver.hpp
    )

QT4_WRAP_CPP( CustomDbusTypes_MOC ${CustomDbusTypes_HEADERS} )


SET( HEADERS_NEEDED_FOR_DBUS_ADAPTER
        DbusMessagesReceiver.hpp
        MyMessages.hpp
    )

qt4_add_dbus_adaptor( CustomDbusTypes_ADAPTOR_SRC
        com.demo.Chat.xml
        DbusMessagesReceiver.hpp
        DbusMessagesReceiver )

SET( CustomDbusTypes_QT_GENERATED_FILES
        ${CustomDbusTypes_MOC}
        ${CustomDbusTypes_ADAPTOR_SRC} )


add_executable( chat ${CustomDbusTypes_SRC} ${CustomDbusTypes_QT_GENERATED_FILES} )

target_link_libraries( chat
        ${QT_LIBRARIES}
    )

main.cpp :

#include <QApplication>

int main( int argc, char* argv[] )
{
    QApplication app( argc, argv );


    return app.exec();
}

MyMessages.hpp :

#ifndef MYMESSAGES_HPP
#define MYMESSAGES_HPP

#include <QString>
#include <QMetaType>
#include <QtDBus>

struct MessageData
{
    QString sender;
    QString message;
};


QDBusArgument& operator<<( QDBusArgument & argument, const MessageData & data );
const QDBusArgument& operator>>( const QDBusArgument & argument, MessageData & data );


void registerCommTypes();

Q_DECLARE_METATYPE(MessageData)

#endif

MyMessages.cpp :

#include "MyMessages.hpp"

QDBusArgument &operator<<( QDBusArgument & argument, const MessageData & data )
{
    argument.beginStructure();
    argument << data.sender << data.message;
    argument.endStructure();

    return argument;
}


const QDBusArgument &operator>>( const QDBusArgument & argument, MessageData & data )
{
    argument.beginStructure();
    argument >> data.sender >> data.message;
    argument.endStructure();

    return argument;
}

void registerCommTypes()
{
    qDBusRegisterMetaType<MessageData>();
}

DbusMessagesReceiver.hpp :

#ifndef DBUSMESSAGESRECEIVER_HPP
#define DBUSMESSAGESRECEIVER_HPP

#include <QObject>
#include <QString>

struct MessageData;

class DbusMessagesReceiver : public QObject
{
    Q_OBJECT

    public:


    /// Slots called by the DBUS messaging system when a message arrives
    public slots:
        void OnMessageData( const MessageData & data );
};

#endif

DbusMessagesReceiver.cpp :

#include "DbusMessagesReceiver.hpp"

#include "MyMessages.hpp"

#include <iostream>



void DbusMessagesReceiver::OnMessageData( const MessageData & data )
{
    std::cout << data.sender.toStdString() << std::endl;
}

Answer 1

Finally, I figured out, and it is quite easy.

The problem was that I forward declared the MessageData structure in the header file (in DbusMessagesReceiver.hpp to be precise) that is included in the generated source file.

Once I included the header including the definition of the MessageData structure in this header, the problem disappeared.

So, the solution is to change DbusMessagesReceiver.hpp to this:

#ifndef DBUSMESSAGESRECEIVER_HPP
#define DBUSMESSAGESRECEIVER_HPP

#include <QObject>
#include <QString>

#include "MyMessages.hpp"

class DbusMessagesReceiver : public QObject
{
    Q_OBJECT

    public:


    /// Slots called by the DBUS messaging system when a message arrives
    public slots:
        void OnMessageData( const MessageData & data );
};

#endif

Pretty smart from cmake developers - too bad it is not documented :(