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: directives.rs
    path of file: ./repos/autocxx/parser/src
    
    the code of the file until where you have to start completion: // Copyright 2022 Google LLC
//
// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
// https://www.apache.org/licenses/LICENSE-2.0> or the MIT license
// <LICENSE-MIT or https://opensource.org/licenses/MIT>, at your
// option. This file may not be copied, modified, or distributed
// except according to those terms.

use indexmap::map::IndexMap as HashMap;

use once_cell::sync::OnceCell;
use proc_macro2::Ident;
use proc_macro2::Span;
#[cfg(feature = "reproduction_case")]
use proc_macro2::TokenStream;

#[cfg(feature = "reproduction_case")]
use quote::{quote, ToTokens};
use syn::parse::ParseStream;

use crate::config::AllowlistErr;

#[cfg(feature = "reproduction_case")]
use crate::config::Allowlist;

use crate::directive_names::{EXTERN_RUST_FUN, EXTERN_RUST_TYPE, SUBCLASS};
use crate::{AllowlistEntry, IncludeCppConfig};
use crate::{ParseResult, RustFun, RustPath};

pub(crate) struct DirectivesMap {
    pub(crate) need_hexathorpe: HashMap<String, Box<dyn Directive>>,
    pub(crate) need_exclamation: HashMap<String, Box<dyn Directive>>,
}

static DIRECTIVES: OnceCell<DirectivesMap> = OnceCell::new();

pub(crate) fn get_directives() -> &'static DirectivesMap {
    DIRECTIVES.get_or_init(|| {
        let mut need_hexathorpe: HashMap<String, Box<dyn Directive>> = HashMap::new();
        need_hexathorpe.insert("include".into(), Box::new(Inclusion));
        let mut need_exclamation: HashMap<String, Box<dyn Directive>> = HashMap::new();
        need_exclamation.insert("generate".into(), Box::new(Generate(false)));
        need_exclamation.insert("generate_pod".into(), Box::new(Generate(true)));
        need_exclamation.insert("generate_ns".into(), Box::new(GenerateNs));
        need_exclamation.insert("generate_all".into(), Box::new(GenerateAll));
        need_exclamation.insert("safety".into(), Box::new(Safety));
        need_exclamation.insert(
            "pod".into(),
            Box::new(StringList(
                |config| &mut config.pod_requests,
                |config| &config.pod_requests,
            )),
        );
        need_exclamation.insert(
            "block".into(),
            Box::new(StringList(
                |config| &mut config.blocklist,
                |config| &config.blocklist,
            )),
        );
        need_exclamation.insert(
            "block_constructors".into(),
            Box::new(StringList(
                |config| &mut config.constructor_blocklist,
                |config| &config.constructor_blocklist,
            )),
        );
        n
    
pub(crate) fn get_directives() -> &'static DirectivesMap {
    DIRECTIVES.get_or_init(|| {
        let mut need_hexathorpe: HashMap<String, Box<dyn Directive>> = HashMap::new();
        need_hexathorpe.insert("include".into(), Box::new(Inclusion));
        let mut need_exclamation: HashMap<String, Box<dyn Directive>> = HashMap::new();
        need_exclamation.insert("generate".into(), Box::new(Generate(false)));
        need_exclamation.insert("generate_pod".into(), Box::new(Generate(true)));
        need_exclamation.insert("generate_ns".into(), Box::new(GenerateNs));
        need_exclamation.insert("generate_all".into(), Box::new(GenerateAll));
        need_exclamation.insert("safety".into(), Box::new(Safety));
        need_exclamation.insert(
            "pod".into(),
            Box::new(StringList(
                |config| &mut config.pod_requests,
                |config| &config.pod_requests,
            )),
        );
        need_exclamation.insert(
            "block".into(),
            Box::new(StringList(
                |config| &mut config.blocklist,
                |config| &config.blocklist,
            )),
        );
        need_exclamation.insert(
            "block_constructors".into(),
            Box::new(StringList(
                |config| &mut config.constructor_blocklist,
                |config| &config.constructor_blocklist,
            )),
        );
        need_exclamation.insert(
            "instantiable".into(),
            Box::new(StringList(
                |config| &mut config.instantiable,
                |config| &config.instantiable,
            )),
        );
        need_exclamation.insert(
            "parse_only".into(),
            Box::new(BoolFlag(
                |config| &mut config.parse_only,
                |config| &config.parse_only,
            )),
        );
        need_exclamation.insert(
            "exclude_impls".into(),
            Box::new(BoolFlag(
                |config| &mut config.exclude_impls,
                |config| &config.exclude_impls,
            )),
        );
        need_exclamation.insert(
            "exclude_utilities".into(),
            Box::new(BoolFlag(
                |config| &mut config.exclude_utilities,
                |config| &config.exclude_utilities,
            )),
        );
        need_exclamation.insert("name".into(), Box::new(ModName));
        need_exclamation.insert("concrete".into(), Box::new(Concrete));
        need_exclamation.insert("rust_type".into(), Box::new(RustType { output: false }));
        need_exclamation.insert(EXTERN_RUST_TYPE.into(), Box::new(RustType { output: true }));
        need_exclamation.insert(SUBCLASS.into(), Box::new(Subclass));
        need_exclamation.insert(EXTERN_RUST_FUN.into(), Box::new(ExternRustFun));
        need_exclamation.insert(
            "extern_cpp_type".into(),
            Box::new(ExternCppType { opaque: false }),
        );
        need_exclamation.insert(
            "extern_cpp_opaque_type".into(),
            Box::new(ExternCppType { opaque: true }),
        );

        DirectivesMap {
            need_hexathorpe,
            need_exclamation,
        }
    })
}