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use proc_macro2::TokenStream as TokenStream2;
use quote::quote;
use syn::{Fields, Ident, ItemStruct, WhereClause};
use crate::attribute_helpers::{contains_initialize_with, contains_skip};
pub fn struct_de(input: &ItemStruct, cratename: Ident) -> syn::Result<TokenStream2> {
let name = &input.ident;
let (impl_generics, ty_generics, where_clause) = input.generics.split_for_impl();
let mut where_clause = where_clause.map_or_else(
|| WhereClause {
where_token: Default::default(),
predicates: Default::default(),
},
Clone::clone,
);
let init_method = contains_initialize_with(&input.attrs)?;
let return_value = match &input.fields {
Fields::Named(fields) => {
let mut body = TokenStream2::new();
for field in &fields.named {
let field_name = field.ident.as_ref().unwrap();
let delta = if contains_skip(&field.attrs) {
quote! {
#field_name: Default::default(),
}
} else {
let field_type = &field.ty;
where_clause.predicates.push(
syn::parse2(quote! {
#field_type: #cratename::BorshDeserialize
})
.unwrap(),
);
quote! {
#field_name: #cratename::BorshDeserialize::deserialize_reader(reader)?,
}
};
body.extend(delta);
}
quote! {
Self { #body }
}
}
Fields::Unnamed(fields) => {
let mut body = TokenStream2::new();
for _ in 0..fields.unnamed.len() {
let delta = quote! {
#cratename::BorshDeserialize::deserialize_reader(reader)?,
};
body.extend(delta);
}
quote! {
Self( #body )
}
}
Fields::Unit => {
quote! {
Self {}
}
}
};
if let Some(method_ident) = init_method {
Ok(quote! {
impl #impl_generics #cratename::de::BorshDeserialize for #name #ty_generics #where_clause {
fn deserialize_reader<R: borsh::maybestd::io::Read>(reader: &mut R) -> ::core::result::Result<Self, #cratename::maybestd::io::Error> {
let mut return_value = #return_value;
return_value.#method_ident();
Ok(return_value)
}
}
})
} else {
Ok(quote! {
impl #impl_generics #cratename::de::BorshDeserialize for #name #ty_generics #where_clause {
fn deserialize_reader<R: borsh::maybestd::io::Read>(reader: &mut R) -> ::core::result::Result<Self, #cratename::maybestd::io::Error> {
Ok(#return_value)
}
}
})
}
}