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use crate::{
attributes::{parse_attributes, Attributes},
util::add_bounds,
with::{make_with_ty, with_inner},
};
use proc_macro2::TokenStream;
use quote::quote;
use syn::{
parse_quote, punctuated::Punctuated, spanned::Spanned, Data, DeriveInput, Error, Fields,
Generics, Ident, Index,
};
pub fn derive(input: DeriveInput) -> Result<TokenStream, Error> {
let attributes = parse_attributes(&input)?;
derive_deserialize_impl(input, &attributes)
}
fn derive_deserialize_impl(
mut input: DeriveInput,
attributes: &Attributes,
) -> Result<TokenStream, Error> {
let where_clause = input.generics.make_where_clause();
if let Some(ref bounds) = attributes.archive_bound {
add_bounds(bounds, where_clause)?;
}
if let Some(ref bounds) = attributes.deserialize_bound {
add_bounds(bounds, where_clause)?;
}
let mut impl_input_params = Punctuated::default();
impl_input_params.push(parse_quote! { __D: Fallible + ?Sized });
for param in input.generics.params.iter() {
impl_input_params.push(param.clone());
}
let impl_input_generics = Generics {
lt_token: Some(Default::default()),
params: impl_input_params,
gt_token: Some(Default::default()),
where_clause: input.generics.where_clause.clone(),
};
let default_rkyv_path = parse_quote! { ::rkyv };
let rkyv_path = attributes.rkyv_path.as_ref().unwrap_or(&default_rkyv_path);
let with_ty = make_with_ty(rkyv_path);
let name = &input.ident;
let (impl_generics, _, _) = impl_input_generics.split_for_impl();
let (_, ty_generics, where_clause) = input.generics.split_for_impl();
let where_clause = where_clause.unwrap();
let deserialize_impl = match input.data {
Data::Struct(ref data) => match data.fields {
Fields::Named(ref fields) => {
let mut deserialize_where = where_clause.clone();
for field in fields
.named
.iter()
.filter(|f| !f.attrs.iter().any(|a| a.path.is_ident("omit_bounds")))
{
let ty = with_ty(field)?;
deserialize_where
.predicates
.push(parse_quote! { #ty: Archive });
deserialize_where
.predicates
.push(parse_quote! { Archived<#ty>: Deserialize<#ty, __D> });
}
let deserialize_fields = fields.named.iter().map(|f| {
let name = &f.ident;
let ty = with_ty(f).unwrap();
let value = with_inner(
f,
parse_quote! {
Deserialize::<#ty, __D>::deserialize(
&self.#name,
deserializer,
)?
},
)
.unwrap();
quote! { #name: #value }
});
quote! {
impl #impl_generics Deserialize<#name #ty_generics, __D> for Archived<#name #ty_generics> #deserialize_where {
#[inline]
fn deserialize(&self, deserializer: &mut __D) -> ::core::result::Result<#name #ty_generics, __D::Error> {
Ok(#name {
#(#deserialize_fields,)*
})
}
}
}
}
Fields::Unnamed(ref fields) => {
let mut deserialize_where = where_clause.clone();
for field in fields
.unnamed
.iter()
.filter(|f| !f.attrs.iter().any(|a| a.path.is_ident("omit_bounds")))
{
let ty = with_ty(field)?;
deserialize_where
.predicates
.push(parse_quote! { #ty: Archive });
deserialize_where
.predicates
.push(parse_quote! { Archived<#ty>: Deserialize<#ty, __D> });
}
let deserialize_fields = fields.unnamed.iter().enumerate().map(|(i, f)| {
let index = Index::from(i);
let ty = with_ty(f).unwrap();
let value = with_inner(
f,
parse_quote! {
Deserialize::<#ty, __D>::deserialize(
&self.#index,
deserializer,
)?
},
)
.unwrap();
quote! { #value }
});
quote! {
impl #impl_generics Deserialize<#name #ty_generics, __D> for Archived<#name #ty_generics> #deserialize_where {
#[inline]
fn deserialize(&self, deserializer: &mut __D) -> ::core::result::Result<#name #ty_generics, __D::Error> {
Ok(#name(
#(#deserialize_fields,)*
))
}
}
}
}
Fields::Unit => quote! {
impl #impl_generics Deserialize<#name #ty_generics, __D> for Archived<#name #ty_generics> #where_clause {
#[inline]
fn deserialize(&self, _: &mut __D) -> ::core::result::Result<#name #ty_generics, __D::Error> {
Ok(#name)
}
}
},
},
Data::Enum(ref data) => {
let mut deserialize_where = where_clause.clone();
for variant in data.variants.iter() {
match variant.fields {
Fields::Named(ref fields) => {
for field in fields
.named
.iter()
.filter(|f| !f.attrs.iter().any(|a| a.path.is_ident("omit_bounds")))
{
let ty = with_ty(field)?;
deserialize_where
.predicates
.push(parse_quote! { #ty: Archive });
deserialize_where
.predicates
.push(parse_quote! { Archived<#ty>: Deserialize<#ty, __D> });
}
}
Fields::Unnamed(ref fields) => {
for field in fields
.unnamed
.iter()
.filter(|f| !f.attrs.iter().any(|a| a.path.is_ident("omit_bounds")))
{
let ty = with_ty(field)?;
deserialize_where
.predicates
.push(parse_quote! { #ty: Archive });
deserialize_where
.predicates
.push(parse_quote! { Archived<#ty>: Deserialize<#ty, __D> });
}
}
Fields::Unit => (),
}
}
let deserialize_variants = data.variants.iter().map(|v| {
let variant = &v.ident;
match v.fields {
Fields::Named(ref fields) => {
let bindings = fields.named.iter().map(|f| {
let name = &f.ident;
quote! { #name }
});
let fields = fields.named.iter().map(|f| {
let name = &f.ident;
let ty = with_ty(f).unwrap();
let value = with_inner(
f,
parse_quote! {
Deserialize::<#ty, __D>::deserialize(
#name,
deserializer,
)?
},
)
.unwrap();
quote! { #name: #value }
});
quote! {
Self::#variant { #(#bindings,)* } => #name::#variant { #(#fields,)* }
}
}
Fields::Unnamed(ref fields) => {
let bindings = fields.unnamed.iter().enumerate().map(|(i, f)| {
let name = Ident::new(&format!("_{}", i), f.span());
quote! { #name }
});
let fields = fields.unnamed.iter().enumerate().map(|(i, f)| {
let binding = Ident::new(&format!("_{}", i), f.span());
let ty = with_ty(f).unwrap();
let value = with_inner(
f,
parse_quote! {
Deserialize::<#ty, __D>::deserialize(
#binding,
deserializer,
)?
},
)
.unwrap();
quote! { #value }
});
quote! {
Self::#variant( #(#bindings,)* ) => #name::#variant(#(#fields,)*)
}
}
Fields::Unit => {
quote! { Self::#variant => #name::#variant }
}
}
});
quote! {
impl #impl_generics Deserialize<#name #ty_generics, __D> for Archived<#name #ty_generics> #deserialize_where {
#[inline]
fn deserialize(&self, deserializer: &mut __D) -> ::core::result::Result<#name #ty_generics, __D::Error> {
Ok(match self {
#(#deserialize_variants,)*
})
}
}
}
}
Data::Union(_) => {
return Err(Error::new_spanned(
input,
"Deserialize cannot be derived for unions",
))
}
};
Ok(quote! {
#[automatically_derived]
const _: () = {
use #rkyv_path::{Archive, Archived, Deserialize, Fallible};
#deserialize_impl
};
})
}
