frame_support_procedural/no_bound/
clone.rs

1// This file is part of Substrate.
2
3// Copyright (C) Parity Technologies (UK) Ltd.
4// SPDX-License-Identifier: Apache-2.0
5
6// Licensed under the Apache License, Version 2.0 (the "License");
7// you may not use this file except in compliance with the License.
8// You may obtain a copy of the License at
9//
10// 	http://www.apache.org/licenses/LICENSE-2.0
11//
12// Unless required by applicable law or agreed to in writing, software
13// distributed under the License is distributed on an "AS IS" BASIS,
14// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
15// See the License for the specific language governing permissions and
16// limitations under the License.
17
18use syn::spanned::Spanned;
19
20/// Derive Clone but do not bound any generic.
21pub fn derive_clone_no_bound(input: proc_macro::TokenStream) -> proc_macro::TokenStream {
22	let input = syn::parse_macro_input!(input as syn::DeriveInput);
23
24	let name = &input.ident;
25	let (impl_generics, ty_generics, where_clause) = input.generics.split_for_impl();
26
27	let impl_ = match input.data {
28		syn::Data::Struct(struct_) => match struct_.fields {
29			syn::Fields::Named(named) => {
30				let fields = named.named.iter().map(|i| &i.ident).map(|i| {
31					quote::quote_spanned!(i.span() =>
32						#i: ::core::clone::Clone::clone(&self.#i)
33					)
34				});
35
36				quote::quote!( Self { #( #fields, )* } )
37			},
38			syn::Fields::Unnamed(unnamed) => {
39				let fields =
40					unnamed.unnamed.iter().enumerate().map(|(i, _)| syn::Index::from(i)).map(|i| {
41						quote::quote_spanned!(i.span() =>
42							::core::clone::Clone::clone(&self.#i)
43						)
44					});
45
46				quote::quote!( Self ( #( #fields, )* ) )
47			},
48			syn::Fields::Unit => {
49				quote::quote!(Self)
50			},
51		},
52		syn::Data::Enum(enum_) => {
53			let variants = enum_.variants.iter().map(|variant| {
54				let ident = &variant.ident;
55				match &variant.fields {
56					syn::Fields::Named(named) => {
57						let captured = named.named.iter().map(|i| &i.ident);
58						let cloned = captured.clone().map(|i| {
59							::quote::quote_spanned!(i.span() =>
60								#i: ::core::clone::Clone::clone(#i)
61							)
62						});
63						quote::quote!(
64							Self::#ident { #( ref #captured, )* } => Self::#ident { #( #cloned, )*}
65						)
66					},
67					syn::Fields::Unnamed(unnamed) => {
68						let captured = unnamed
69							.unnamed
70							.iter()
71							.enumerate()
72							.map(|(i, f)| syn::Ident::new(&format!("_{}", i), f.span()));
73						let cloned = captured.clone().map(|i| {
74							quote::quote_spanned!(i.span() =>
75								::core::clone::Clone::clone(#i)
76							)
77						});
78						quote::quote!(
79							Self::#ident ( #( ref #captured, )* ) => Self::#ident ( #( #cloned, )*)
80						)
81					},
82					syn::Fields::Unit => quote::quote!( Self::#ident => Self::#ident ),
83				}
84			});
85
86			quote::quote!(match self {
87				#( #variants, )*
88			})
89		},
90		syn::Data::Union(_) => {
91			let msg = "Union type not supported by `derive(CloneNoBound)`";
92			return syn::Error::new(input.span(), msg).to_compile_error().into()
93		},
94	};
95
96	quote::quote!(
97		const _: () = {
98			#[automatically_derived]
99			#[allow(deprecated)]
100			impl #impl_generics ::core::clone::Clone for #name #ty_generics #where_clause {
101				fn clone(&self) -> Self {
102					#impl_
103				}
104			}
105		};
106	)
107	.into()
108}
frame_support_procedural/no_bound/clone.rs

frame_support_procedural/no_bound/
clone.rs
