dom_struct/
lib.rs

1/* This Source Code Form is subject to the terms of the Mozilla Public
2 * License, v. 2.0. If a copy of the MPL was not distributed with this
3 * file, You can obtain one at https://mozilla.org/MPL/2.0/. */
4
5#![recursion_limit = "128"]
6
7use proc_macro::TokenStream;
8use quote::quote;
9use syn::*;
10mod domobject;
11use crate::domobject::expand_dom_object;
12
13#[proc_macro_attribute]
14pub fn dom_struct(args: TokenStream, input: TokenStream) -> TokenStream {
15    let associated_memory = args.to_string().contains("associated_memory");
16    if !associated_memory && !args.is_empty() {
17        panic!("#[dom_struct] only takes 'associated_memory' as an argument");
18    }
19    let attributes = quote! {
20        #[derive(deny_public_fields::DenyPublicFields, JSTraceable, MallocSizeOf)]
21        #[cfg_attr(crown, crown::unrooted_must_root_lint::must_root)]
22        #[repr(C)]
23    };
24
25    // Work around https://github.com/rust-lang/rust/issues/46489
26    let attributes: TokenStream = attributes.to_string().parse().unwrap();
27
28    let output: TokenStream = attributes.into_iter().chain(input).collect();
29
30    let item: Item = syn::parse(output).unwrap();
31
32    if let Item::Struct(s) = item {
33        let expanded_dom_object = expand_dom_object(s.clone(), associated_memory);
34        let s2 = quote! { #s #expanded_dom_object };
35        if !s.generics.params.is_empty() {
36            return s2.into();
37        }
38        if let Fields::Named(ref f) = s.fields {
39            let f = f.named.first().expect("Must have at least one field");
40            let ident = f.ident.as_ref().expect("Must have named fields");
41            let name = &s.ident;
42            let ty = &f.ty;
43
44            quote! (
45                #s2
46
47                impl crate::HasParent for #name {
48                    type Parent = #ty;
49                    /// This is used in a type assertion to ensure that
50                    /// the source and webidls agree as to what the parent type is
51                    fn as_parent(&self) -> &#ty {
52                        &self.#ident
53                    }
54                }
55            )
56            .into()
57        } else {
58            panic!("#[dom_struct] only applies to structs with named fields");
59        }
60    } else {
61        panic!("#[dom_struct] only applies to structs");
62    }
63}
dom_struct/lib.rs

dom_struct/
lib.rs
