rkyv_derive 0.8.16

Derive macro for rkyv
Documentation 
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use core::iter::FlatMap;

use proc_macro2::Ident;
use syn::{
    punctuated::Iter, Data, DataEnum, DataStruct, DataUnion, Field, Path,
    PathArguments, Variant,
};

pub fn strip_raw(ident: &Ident) -> String {
    let as_string = ident.to_string();
    as_string
        .strip_prefix("r#")
        .map(ToString::to_string)
        .unwrap_or(as_string)
}

type VariantFieldsFn = fn(&Variant) -> Iter<'_, Field>;

fn variant_fields(variant: &Variant) -> Iter<'_, Field> {
    variant.fields.iter()
}

pub enum FieldsIter<'a> {
    Struct(Iter<'a, Field>),
    Enum(FlatMap<Iter<'a, Variant>, Iter<'a, Field>, VariantFieldsFn>),
}

impl<'a> Iterator for FieldsIter<'a> {
    type Item = &'a Field;

    fn next(&mut self) -> Option<Self::Item> {
        match self {
            Self::Struct(iter) => iter.next(),
            Self::Enum(iter) => iter.next(),
        }
    }
}

pub fn iter_fields(data: &Data) -> FieldsIter<'_> {
    match data {
        Data::Struct(DataStruct { fields, .. }) => {
            FieldsIter::Struct(fields.iter())
        }
        Data::Enum(DataEnum { variants, .. }) => {
            FieldsIter::Enum(variants.iter().flat_map(variant_fields))
        }
        Data::Union(DataUnion { fields, .. }) => {
            FieldsIter::Struct(fields.named.iter())
        }
    }
}

pub fn strip_generics_from_path(mut path: Path) -> Path {
    for segment in path.segments.iter_mut() {
        segment.arguments = PathArguments::None;
    }

    path
}