You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: cpp_code_generator.rs
    path of file: ./repos/ritual/ritual/src
    
    the code of the file until where you have to start completion: use crate::config::Config;
use crate::cpp_checks::Condition;
use crate::cpp_ffi_data::{
    CppFfiArgumentMeaning, CppFfiFunctionKind, CppFfiType, CppFieldAccessorType,
    CppToFfiTypeConversion, QtSignalWrapper, QtSlotWrapper,
};
use crate::cpp_ffi_data::{CppFfiFunction, CppFfiItem};
use crate::cpp_function::{CppFunction, ReturnValueAllocationPlace};
use crate::cpp_type::CppPointerLikeTypeKind;
use crate::cpp_type::CppType;
use crate::database::{DatabaseClient, DbItem};
use crate::rust_info::{RustItem, RustStructKind};
use itertools::Itertools;
use ritual_common::cpp_lib_builder::version_to_number;
use ritual_common::errors::{bail, err_msg, format_err, Result};
use ritual_common::file_utils::{create_file, os_str_to_str, path_to_str, read_dir};
use ritual_common::utils::MapIfOk;
use std::collections::HashSet;
use std::io::Write;
use std::iter::once;
use std::path::{Path, PathB
    
    fn qt_slot_wrapper(&self, wrapper: &QtSlotWrapper) -> Result<String> {
        let func_type = CppType::FunctionPointer(wrapper.function_type.clone());
        let method_args = wrapper
            .arguments
            .iter()
            .enumerate()
            .map_if_ok(|(num, t)| -> Result<_> {
                let arg_type = t.original_type().to_cpp_code(None)?;
                let arg_type = CppFunction::patch_receiver_argument_type(&arg_type);
                Ok(format!("{} arg{}", arg_type, num))
            })?
            .join(", ");
        let func_args = once("m_callback.data()".to_string())
            .chain(
                wrapper
                    .arguments
                    .iter()
                    .enumerate()
                    .map_if_ok(|(num, t)| self.convert_type_to_ffi(t, format!("arg{}", num)))?,
            )
            .join(", ");
        Ok(format!(
            include_str!("../templates/c_lib/qt_slot_wrapper.h"),
            class_name = wrapper.class_path.to_cpp_code()?,
            callback_arg = func_type.to_cpp_code(Some("callback"))?,
            callback_type = func_type.to_cpp_code(Some(""))?,
            method_args = method_args,
            func_args = func_args
        ))
    }