use proc_macro::TokenStream;
use proc_macro2::{Ident as Ident2, TokenStream as TokenStream2};
use quote::{quote, TokenStreamExt};
use syn::{parse_macro_input, Data, DataStruct, DeriveInput, Fields};
#[proc_macro_derive(CLTyped)]
pub fn derive_cl_typed(input: TokenStream) -> TokenStream {
let input = parse_macro_input!(input as DeriveInput);
let ident = input.ident;
let expanded = quote! {
impl casper_types::CLTyped for #ident {
fn cl_type() -> casper_types::CLType {
casper_types::CLType::Any
}
}
};
TokenStream::from(expanded)
}
fn named_fields(input: DeriveInput) -> Result<Vec<Ident2>, TokenStream> {
let fields = match input.data {
Data::Struct(DataStruct {
fields: Fields::Named(named_fields),
..
}) => named_fields
.named
.into_iter()
.map(|x| x.ident.unwrap())
.collect::<Vec<_>>(),
_ => {
return Err(TokenStream::from(
quote! { compile_error!("Expected a struct with named fields."); },
))
}
};
Ok(fields)
}
#[proc_macro_derive(FromBytes)]
pub fn derive_from_bytes(input: TokenStream) -> TokenStream {
let input = parse_macro_input!(input as DeriveInput);
let struct_ident = input.ident.clone();
let fields = match named_fields(input) {
Ok(fields) => fields,
Err(error_stream) => return error_stream,
};
let mut deserialize_fields = TokenStream2::new();
deserialize_fields.append_all(fields.iter().map(|ident| {
quote! {
let (#ident, bytes) = casper_types::bytesrepr::FromBytes::from_bytes(bytes)?;
}
}));
let mut construct_struct = TokenStream2::new();
construct_struct.append_all(fields.iter().map(|ident| quote! { #ident, }));
let expanded = quote! {
impl casper_types::bytesrepr::FromBytes for #struct_ident {
fn from_bytes(bytes: &[u8]) -> Result<(Self, &[u8]), casper_types::bytesrepr::Error> {
#deserialize_fields
let value = #struct_ident {
#construct_struct
};
Ok((value, bytes))
}
}
};
TokenStream::from(expanded)
}
#[proc_macro_derive(ToBytes)]
pub fn derive_to_bytes(input: TokenStream) -> TokenStream {
let input = parse_macro_input!(input as DeriveInput);
let struct_ident = input.ident.clone();
let fields = match named_fields(input) {
Ok(fields) => fields,
Err(error_stream) => return error_stream,
};
let mut sum_serialized_lengths = TokenStream2::new();
sum_serialized_lengths.append_all(fields.iter().map(|ident| {
quote! {
size += self.#ident.serialized_length();
}
}));
let mut append_bytes = TokenStream2::new();
append_bytes.append_all(fields.iter().map(|ident| {
quote! {
vec.extend(self.#ident.to_bytes()?);
}
}));
let expanded = quote! {
impl casper_types::bytesrepr::ToBytes for #struct_ident {
fn serialized_length(&self) -> usize {
let mut size = 0;
#sum_serialized_lengths
return size;
}
fn to_bytes(&self) -> Result<Vec<u8>, casper_types::bytesrepr::Error> {
let mut vec = Vec::with_capacity(self.serialized_length());
#append_bytes
Ok(vec)
}
}
};
TokenStream::from(expanded)
}