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|
use std::collections::HashMap;
use darling::{FromAttributes, FromMeta};
use proc_macro::TokenStream;
use proc_macro2::{Ident, Span, TokenStream as TokenStream2};
use quote::quote;
use syn::{parse, ItemStruct};
#[derive(Debug, Default, FromAttributes)]
#[darling(attributes(ppproperly))]
#[darling(default)]
struct Args {
discriminant_for: Option<DiscriminantArgs>,
len_for: Option<LenArgs>,
}
#[derive(Debug, Default, FromMeta)]
struct DiscriminantArgs {
field: String,
data_type: String,
}
#[derive(Debug, Default, FromMeta)]
struct LenArgs {
field: String,
offset: u8,
data_type: String,
}
#[proc_macro_derive(Serialize, attributes(ppproperly))]
pub fn derive_serialize(item: TokenStream) -> TokenStream {
let ast: ItemStruct = parse(item).unwrap();
let name = ast.ident;
let serializers = ast.fields.iter().map(|field| {
let mut out = TokenStream2::new();
let field_name = field.ident.as_ref().expect("should be a names struct");
let args = Args::from_attributes(&field.attrs).unwrap();
if let Some(attr) = args.discriminant_for {
let field_ident = Ident::new(&attr.field, Span::call_site());
out.extend(
vec![quote!(
self.#field_ident.discriminant().serialize(w)?;
)]
.into_iter(),
);
}
if let Some(attr) = args.len_for {
let field_ident = Ident::new(&attr.field, Span::call_site());
let offset = attr.offset;
let data_type_ident = Ident::new(&attr.data_type, Span::call_site());
out.extend(
vec![quote!(
(self.#field_ident.len() + #data_type_ident::from(#offset)).serialize(w)?;
)]
.into_iter(),
);
}
out.extend(
vec![quote!(
self.#field_name.serialize(w)?;
)]
.into_iter(),
);
out
});
quote!(
impl Serialize for #name {
fn serialize<W: std::io::Write>(&self, w: &mut W) -> Result<()> {
#(#serializers) *
Ok(())
}
}
)
.into()
}
#[proc_macro_derive(Deserialize, attributes(ppproperly))]
pub fn derive_deserialize(item: TokenStream) -> TokenStream {
let ast: ItemStruct = parse(item).unwrap();
let name = ast.ident;
let mut discriminant_for = HashMap::new();
let mut len_for = HashMap::new();
let has_discriminant_annotations = ast.fields.iter().any(|field| {
let args = Args::from_attributes(&field.attrs).unwrap();
args.discriminant_for.is_some()
});
let has_len_annotations = ast.fields.iter().any(|field| {
let args = Args::from_attributes(&field.attrs).unwrap();
args.len_for.is_some()
});
let mut map_declarations = TokenStream2::new();
if has_discriminant_annotations {
map_declarations.extend(
vec![quote!(
let mut discriminant_for = std::collections::HashMap::new();
)]
.into_iter(),
);
}
if has_len_annotations {
map_declarations.extend(
vec![quote!(
let mut len_for = std::collections::HashMap::new();
)]
.into_iter(),
);
}
let deserializers = ast.fields.iter().map(|field| {
let mut out = TokenStream2::new();
let field_name = field.ident.as_ref().expect("should be a names struct");
let field_name_string = field_name.to_string();
let args = Args::from_attributes(&field.attrs).unwrap();
if let Some(attr) = args.discriminant_for {
let field = attr.field;
let data_type_ident = Ident::new(&attr.data_type, Span::call_site());
out.extend(
vec![quote!(
let mut discriminant = #data_type_ident::default();
discriminant.deserialize(r)?;
discriminant_for.insert(#field, discriminant);
)]
.into_iter(),
);
discriminant_for.insert(field, ());
}
if let Some(attr) = args.len_for {
let field = attr.field;
let offset = attr.offset;
let data_type_ident = Ident::new(&attr.data_type, Span::call_site());
out.extend(
vec![quote!(
let mut len = #data_type_ident::default();
len.deserialize(r)?;
len_for.insert(#field, len - #data_type_ident::from(#offset));
)]
.into_iter(),
);
len_for.insert(field, ());
}
if len_for.contains_key(&field_name.to_string()) {
out.extend(
vec![quote!(
let t = r.take(*len_for.get(#field_name_string).unwrap() as u64);
)]
.into_iter(),
);
}
if discriminant_for.contains_key(&field_name.to_string()) {
out.extend(
vec![quote!(
let attr = discriminant_for.get(#field_name_string).unwrap();
self.#field_name.deserialize_with_discriminant(&mut t, attr)?;
)]
.into_iter(),
);
} else {
out.extend(
vec![quote!(
self.#field_name.deserialize(r)?;
)]
.into_iter(),
);
}
out
});
quote!(
impl Deserialize for #name {
fn deserialize<R: std::io::Read>(&mut self, r: &mut R) -> Result<()> {
#map_declarations
#(#deserializers) *
Ok(())
}
}
)
.into()
}
|
