reflect_opaque.rs

use crate::{
    container_attributes::ContainerAttributes, derive_data::ReflectTraitToImpl,
    type_path::CustomPathDef,
};
use syn::{parenthesized, parse::ParseStream, token::Paren, Attribute, Generics, Path};

/// A struct used to define a simple reflection-opaque types (including primitives).
///
/// This takes the form:
///
/// ```ignore (Method expecting TokenStream is better represented with raw tokens)
/// // Standard
/// ::my_crate::foo::Bar(TraitA, TraitB)
///
/// // With generics
/// ::my_crate::foo::Bar<T1: Bar, T2>(TraitA, TraitB)
///
/// // With generics and where clause
/// ::my_crate::foo::Bar<T1, T2> where T1: Bar (TraitA, TraitB)
///
/// // With a custom path (not with impl_from_reflect_opaque)
/// (in my_crate::bar) Bar(TraitA, TraitB)
/// ```
pub(crate) struct ReflectOpaqueDef {
    #[cfg_attr(
        not(feature = "documentation"),
        expect(
            dead_code,
            reason = "The is used when the `documentation` feature is enabled.",
        )
    )]
    pub attrs: Vec<Attribute>,
    pub type_path: Path,
    pub generics: Generics,
    pub traits: Option<ContainerAttributes>,
    pub custom_path: Option<CustomPathDef>,
}

impl ReflectOpaqueDef {
    pub fn parse_reflect(input: ParseStream) -> syn::Result<Self> {
        Self::parse(input, ReflectTraitToImpl::Reflect)
    }

    pub fn parse_from_reflect(input: ParseStream) -> syn::Result<Self> {
        Self::parse(input, ReflectTraitToImpl::FromReflect)
    }

    fn parse(input: ParseStream, trait_: ReflectTraitToImpl) -> syn::Result<Self> {
        let attrs = input.call(Attribute::parse_outer)?;

        let custom_path = CustomPathDef::parse_parenthesized(input)?;

        let type_path = Path::parse_mod_style(input)?;
        let mut generics = input.parse::<Generics>()?;
        generics.where_clause = input.parse()?;

        let mut traits = None;
        if input.peek(Paren) {
            let content;
            parenthesized!(content in input);
            traits = Some({
                let mut attrs = ContainerAttributes::default();
                attrs.parse_terminated(&content, trait_)?;
                attrs
            });
        }
        Ok(Self {
            attrs,
            type_path,
            generics,
            traits,
            custom_path,
        })
    }
}