[Feature Request] Make XPCF_IGNORE the default regarding generation of gRPC clients and services

[jim-bcom]

PROBLEM

• Our project contains quite a lot of XPCF components subject to have gRPC files being generated by xpcf_grpc_gen.
• We want to generate those files only for a subset of these classes
• We must use XPCF_IGNORE macro for a majority of component and keep XPCF_CLIENTUUID/XPCF_SERVERUUID only for a handful of classes, because, IIUC, unannotated class uses generated UUIDs :

ProxyGenerator.cpp

xpcf::uuids::uuid proxyUUID = c->getClientUUID();
    if (proxyUUID.is_nil()) {
        proxyUUID = c->createClientUUID();
        m_serviceUuidMap[m_className] = xpcf::uuids::to_string(proxyUUID);
    }

• => this can be tedious and hard to check we haven't forgotten to add an XPCF_IGNORE somewhere as it will likely generate files we do not use, and only increase compilation time to our project that uses those generated files.

SUGGESTED SOLUTION

• Invert the default, and consider an unannotated class to be ignored, and explicitely add annotation for generation.

For example:

• set both UUIDs

class XPCF_CLIENTUUID("...") XPCF_SERVERUUID("...") MyClass:
    virtual public org::bcom::xpcf::IComponentIntrospect {

• set only one UUID, let the other one be generated (error if not both are set?)

class XPCF_CLIENTUUID("...") XPCF_SERVERUUID_AUTO MyClass:
    virtual public org::bcom::xpcf::IComponentIntrospect {

• no annotation -> ignored

class MyClass:
    virtual public org::bcom::xpcf::IComponentIntrospect {