Create a custom function for Ice

[Neloy262]

The issue

I would like to create a custom function in the mumble server and invoke it using Ice. How would I be able to do it?

Mumble version

1.4.0

Mumble component

Server

OS

Linux

Additional information

No response

[Krzmbrzl]

The general process is documented at https://github.com/mumble-voip/mumble/blob/master/docs/dev/ExtendingTheIceInterface.md

The first step obviously is to add the function to the MumbleServer.ice file. After that you should be able to follow the instructions in the linked document.

Let me know if you have further questions

[Neloy262]

Following the doc I created a simple function that just prints to the console. The code for the impl function is as follows:

static void impl_Server_helloIce(const ::MumbleServer::AMD_Server_helloIcePtr &cb, const ::Ice::Current &current){

    int server_id = u8(current.id.name).toInt();
    std::cout<<"HELLO ICE --------------"<<server_id<<std::endl;
    cb->ice_response();
}

After building I am getting the following error: error: invalid initialization of reference of type ‘const Ice::Current&’ from expression of type ‘int’

this is the part of the code where the error is pointing

ExecEvent *ie = new ExecEvent(boost::bind(&impl_Server_helloIce, cb, QString::fromStdString(current.id.name).toInt()));

[Krzmbrzl]

What is the full error message?

[Neloy262]

/usr/bin/c++ -DDEBUG -DICE_STATIC_LIBS -DMUMBLE_BUILD_YEAR=2023 -DMUMBLE_TARGET_ARCH=\"x64\" -DMUMBLE_TARGET_OS=\"linux\" -DMUMBLE_VERSION=1.5.0 -DMUMBLE_VERSION_MAJOR=1 -DMUMBLE_VERSION_MINOR=5 -DMUMBLE_VERSION_PATCH=0 -DMURMUR -DQT_CORE_LIB -DQT_DBUS_LIB -DQT_NETWORK_LIB -DQT_RESTRICTED_CAST_FROM_ASCII -DQT_SQL_LIB -DQT_USE_FAST_CONCATENATION -DQT_USE_FAST_OPERATOR_PLUS -DQT_XML_LIB -DSNAPSHOT_BUILD -DTRACY_ON_DEMAND -DUSE_DBUS -DUSE_ICE -DUSE_QSSLDIFFIEHELLMANPARAMETERS -DUSE_ZEROCONF -D_USE_MATH_DEFINES -I"/media/nybsysml/New Volume/Niloy/sentra_dev/mumble-source-code/cmake-build-debug/src/murmur/mumble-server_autogen/include" -I"/media/nybsysml/New Volume/Niloy/sentra_dev/mumble-source-code/src/murmur" -I"/media/nybsysml/New Volume/Niloy/sentra_dev/mumble-source-code/src" -I/usr/include/avahi-compat-libdns_sd -I"/media/nybsysml/New Volume/Niloy/sentra_dev/mumble-source-code/3rdparty/qqbonjour" -I"/media/nybsysml/New Volume/Niloy/sentra_dev/mumble-source-code/cmake-build-debug/src/murmur" -I"/media/nybsysml/New Volume/Niloy/sentra_dev/mumble-source-code/cmake-build-debug/src" -isystem /home/nybsysml/.local/include -isystem /usr/include/x86_64-linux-gnu/qt5 -isystem /usr/include/x86_64-linux-gnu/qt5/QtCore -isystem /usr/lib/x86_64-linux-gnu/qt5/mkspecs/linux-g++ -isystem /usr/include/x86_64-linux-gnu/qt5/QtNetwork -isystem /usr/include/x86_64-linux-gnu/qt5/QtXml -isystem "/media/nybsysml/New Volume/Niloy/sentra_dev/mumble-source-code/3rdparty/tracy" -isystem "/media/nybsysml/New Volume/Niloy/sentra_dev/mumble-source-code/3rdparty/gsl/include" -isystem /usr/include/x86_64-linux-gnu/qt5/QtSql -isystem /usr/include/x86_64-linux-gnu/qt5/QtDBus -g -fPIE -fvisibility=hidden -Wall -Wextra -Werror -U_FORTIFY_SOURCE -fstack-protector -fPIC -std=gnu++14 -MD -MT src/murmur/CMakeFiles/mumble-server.dir/MumbleServerIce.cpp.o -MF src/murmur/CMakeFiles/mumble-server.dir/MumbleServerIce.cpp.o.d -o src/murmur/CMakeFiles/mumble-server.dir/MumbleServerIce.cpp.o -c '/media/nybsysml/New Volume/Niloy/sentra_dev/mumble-source-code/src/murmur/MumbleServerIce.cpp'
In file included from /media/nybsysml/New Volume/Niloy/sentra_dev/mumble-source-code/cmake-build-debug/src/murmur/MumbleServerIceWrapper.cpp:3,
                 from /media/nybsysml/New Volume/Niloy/sentra_dev/mumble-source-code/src/murmur/MumbleServerIce.cpp:2013:
/usr/include/boost/bind/bind.hpp: In instantiation of ‘void boost::_bi::list2<A1, A2>::operator()(boost::_bi::type<void>, F&, A&, int) [with F = void (*)(const IceUtil::Handle<MumbleServer::AMD_Server_helloIce>&, const Ice::Current&); A = boost::_bi::list0; A1 = boost::_bi::value<IceUtil::Handle<MumbleServer::AMD_Server_helloIce> >; A2 = boost::_bi::value<int>]’:
/usr/include/boost/bind/bind.hpp:1294:50:   required from ‘boost::_bi::bind_t<R, F, L>::result_type boost::_bi::bind_t<R, F, L>::operator()() [with R = void; F = void (*)(const IceUtil::Handle<MumbleServer::AMD_Server_helloIce>&, const Ice::Current&); L = boost::_bi::list2<boost::_bi::value<IceUtil::Handle<MumbleServer::AMD_Server_helloIce> >, boost::_bi::value<int> >; boost::_bi::bind_t<R, F, L>::result_type = void]’
/usr/include/boost/function/function_template.hpp:158:11:   required from ‘static void boost::detail::function::void_function_obj_invoker0<FunctionObj, R>::invoke(boost::detail::function::function_buffer&) [with FunctionObj = boost::_bi::bind_t<void, void (*)(const IceUtil::Handle<MumbleServer::AMD_Server_helloIce>&, const Ice::Current&), boost::_bi::list2<boost::_bi::value<IceUtil::Handle<MumbleServer::AMD_Server_helloIce> >, boost::_bi::value<int> > >; R = void]’
/usr/include/boost/function/function_template.hpp:931:38:   required from ‘void boost::function0<R>::assign_to(Functor) [with Functor = boost::_bi::bind_t<void, void (*)(const IceUtil::Handle<MumbleServer::AMD_Server_helloIce>&, const Ice::Current&), boost::_bi::list2<boost::_bi::value<IceUtil::Handle<MumbleServer::AMD_Server_helloIce> >, boost::_bi::value<int> > >; R = void]’
/usr/include/boost/function/function_template.hpp:720:7:   required from ‘boost::function0<R>::function0(Functor, typename boost::enable_if_<(! boost::is_integral<Functor>::value), int>::type) [with Functor = boost::_bi::bind_t<void, void (*)(const IceUtil::Handle<MumbleServer::AMD_Server_helloIce>&, const Ice::Current&), boost::_bi::list2<boost::_bi::value<IceUtil::Handle<MumbleServer::AMD_Server_helloIce> >, boost::_bi::value<int> > >; R = void; typename boost::enable_if_<(! boost::is_integral<Functor>::value), int>::type = int]’
/usr/include/boost/function/function_template.hpp:1068:16:   required from ‘boost::function<R()>::function(Functor, typename boost::enable_if_<(! boost::is_integral<Functor>::value), int>::type) [with Functor = boost::_bi::bind_t<void, void (*)(const IceUtil::Handle<MumbleServer::AMD_Server_helloIce>&, const Ice::Current&), boost::_bi::list2<boost::_bi::value<IceUtil::Handle<MumbleServer::AMD_Server_helloIce> >, boost::_bi::value<int> > >; R = void; typename boost::enable_if_<(! boost::is_integral<Functor>::value), int>::type = int]’
/media/nybsysml/New Volume/Niloy/sentra_dev/mumble-source-code/cmake-build-debug/src/murmur/MumbleServerIceWrapper.cpp:97:119:   required from here
/usr/include/boost/bind/bind.hpp:319:35: error: invalid initialization of reference of type ‘const Ice::Current&’ from expression of type ‘int’
  319 |         unwrapper<F>::unwrap(f, 0)(a[base_type::a1_], a[base_type::a2_]);
      |         ~~~~~~~~~~~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
ninja: build stopped: subcommand failed.

[Krzmbrzl]

MumbleServerIceWrapper.cpp:97:119

This is an auto-generated file that can be found in your build folder (under src/murmur). I assume this is related to how you obtain the server ID.

Why are you not using a plain int for the server ID in the first place? That seems to be what every other function does 👀

[Neloy262]

I did it like that just to utilize the current function argument.

[Neloy262]

The auto-generated function declaration contained const ::Ice::Current &current as a parameter.

[Krzmbrzl]

Do you have the source code available somewhere? I have the feeling it won't work in this remote debugging kind of way. I have to see the entire project in order to comment on this.

[Neloy262]

github link: https://github.com/Neloy262/Mumble

please check the debug branch.

the *impl function is implemented inside MumbleServerIce.cpp line 1976

[Krzmbrzl]

Alright - have a look at https://github.com/Neloy262/Mumble/blob/6127ab2730af6ea326e81b1943afbcc8941b1175/src/murmur/MumbleServerIce.cpp#L896 which. There you can see that the server ID is simply passed in as a plain int parameter.

All functions taking a Ice::Current argument, at first glance, appear to be more or less "internal" function that don't show up in the ice file.

If you look closer, the conversion from the current argument into the plain integer is performed in the auto-generated MumbleServerIceWrapper.cpp file where it creates the ExecEvent instance.

[Neloy262]

Thanks, this solved my problem.