tetsy_codec_derive/
lib.rs

1// Copyright 2017-2018 Parity Technologies
2//
3// Licensed under the Apache License, Version 2.0 (the "License");
4// you may not use this file except in compliance with the License.
5// You may obtain a copy of the License at
6//
7//     http://www.apache.org/licenses/LICENSE-2.0
8//
9// Unless required by applicable law or agreed to in writing, software
10// distributed under the License is distributed on an "AS IS" BASIS,
11// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
12// See the License for the specific language governing permissions and
13// limitations under the License.
14
15//! Derives serialization and deserialization codec for complex structs for simple marshalling.
16
17extern crate proc_macro;
18extern crate proc_macro2;
19
20#[macro_use]
21extern crate syn;
22
23#[macro_use]
24extern crate quote;
25
26use proc_macro::TokenStream;
27use proc_macro2::Span;
28use syn::{DeriveInput, Generics, GenericParam, Ident};
29
30mod decode;
31mod encode;
32mod utils;
33
34const ENCODE_ERR: &str = "derive(Encode) failed";
35
36#[proc_macro_derive(Encode, attributes(codec))]
37pub fn encode_derive(input: TokenStream) -> TokenStream {
38	let input: DeriveInput = syn::parse(input).expect(ENCODE_ERR);
39	let name = &input.ident;
40
41	let generics = add_trait_bounds(input.generics, parse_quote!(_tetsy_codec::Encode));
42	let (impl_generics, ty_generics, where_clause) = generics.split_for_impl();
43
44	let self_ = quote!(self);
45	let dest_ = quote!(dest);
46	let encoding = encode::quote(&input.data, name, &self_, &dest_);
47
48	let impl_block = quote! {
49		impl #impl_generics _tetsy_codec::Encode for #name #ty_generics #where_clause {
50			fn encode_to<EncOut: _tetsy_codec::Output>(&#self_, #dest_: &mut EncOut) {
51				#encoding
52			}
53		}
54	};
55
56	let mut new_name = "_IMPL_ENCODE_FOR_".to_string();
57	new_name.push_str(name.to_string().trim_start_matches("r#"));
58	let dummy_const = Ident::new(&new_name, Span::call_site());
59
60	let generated = quote! {
61		#[allow(non_upper_case_globals, unused_attributes, unused_qualifications)]
62		const #dummy_const: () = {
63			#[allow(unknown_lints)]
64			#[cfg_attr(feature = "cargo-clippy", allow(useless_attribute))]
65			#[allow(rust_2018_idioms)]
66			extern crate tetsy_codec as _tetsy_codec;
67			#impl_block
68		};
69	};
70
71	generated.into()
72}
73
74#[proc_macro_derive(Decode, attributes(codec))]
75pub fn decode_derive(input: TokenStream) -> TokenStream {
76	let input: DeriveInput = syn::parse(input).expect(ENCODE_ERR);
77	let name = &input.ident;
78
79	let generics = add_trait_bounds(input.generics, parse_quote!(_tetsy_codec::Decode));
80	let (impl_generics, ty_generics, where_clause) = generics.split_for_impl();
81
82	let input_ = quote!(input);
83	let decoding = decode::quote(&input.data, name, &input_);
84
85	let impl_block = quote! {
86		impl #impl_generics _tetsy_codec::Decode for #name #ty_generics #where_clause {
87			fn decode<DecIn: _tetsy_codec::Input>(#input_: &mut DecIn) -> Option<Self> {
88				#decoding
89			}
90		}
91	};
92
93	let mut new_name = "_IMPL_DECODE_FOR_".to_string();
94	new_name.push_str(name.to_string().trim_start_matches("r#"));
95	let dummy_const = Ident::new(&new_name, Span::call_site());
96
97	let generated = quote! {
98		#[allow(non_upper_case_globals, unused_attributes, unused_qualifications)]
99		const #dummy_const: () = {
100			#[allow(unknown_lints)]
101			#[cfg_attr(feature = "cargo-clippy", allow(useless_attribute))]
102			#[allow(rust_2018_idioms)]
103			extern crate tetsy_codec as _tetsy_codec;
104			#impl_block
105		};
106	};
107
108	generated.into()
109}
110
111fn add_trait_bounds(mut generics: Generics, bounds: syn::TypeParamBound) -> Generics {
112	for param in &mut generics.params {
113		if let GenericParam::Type(ref mut type_param) = *param {
114			type_param.bounds.push(bounds.clone());
115		}
116	}
117	generics
118}
tetsy_codec_derive/lib.rs

tetsy_codec_derive/
lib.rs
