third_party_rust_cxx/syntax/improper.rs

use self::ImproperCtype::*;
use crate::syntax::atom::Atom::{self, *};
use crate::syntax::{Type, Types};
use proc_macro2::Ident;

pub enum ImproperCtype<'a> {
    Definite(bool),
    Depends(&'a Ident),
}

impl<'a> Types<'a> {
    // yes, no, maybe
    pub fn determine_improper_ctype(&self, ty: &Type) -> ImproperCtype<'a> {
        match ty {
            Type::Ident(ident) => {
                let ident = &ident.rust;
                if let Some(atom) = Atom::from(ident) {
                    Definite(atom == RustString)
                } else if let Some(strct) = self.structs.get(ident) {
                    Depends(&strct.name.rust) // iterate to fixed-point
                } else {
                    Definite(self.rust.contains(ident) || self.aliases.contains_key(ident))
                }
            }
            Type::RustBox(_)
            | Type::RustVec(_)
            | Type::Str(_)
            | Type::Fn(_)
            | Type::Void(_)
            | Type::SliceRef(_) => Definite(true),
            Type::UniquePtr(_) | Type::SharedPtr(_) | Type::WeakPtr(_) | Type::CxxVector(_) => {
                Definite(false)
            }
            Type::Ref(ty) => self.determine_improper_ctype(&ty.inner),
            Type::Ptr(ty) => self.determine_improper_ctype(&ty.inner),
            Type::Array(ty) => self.determine_improper_ctype(&ty.inner),
        }
    }
}