ouroboros_macro/generate/
summon_checker.rs

1use proc_macro2::TokenStream;
2use quote::quote;
3use syn::Error;
4
5use crate::info_structures::{ArgType, BuilderType, StructInfo};
6
7pub fn generate_checker_summoner(info: &StructInfo) -> Result<TokenStream, Error> {
8    let mut code: Vec<TokenStream> = Vec::new();
9    let mut params: Vec<TokenStream> = Vec::new();
10    let mut value_consumers: Vec<TokenStream> = Vec::new();
11    let mut template_consumers: Vec<TokenStream> = Vec::new();
12    for field in &info.fields {
13        let field_name = &field.name;
14
15        let arg_type = field.make_constructor_arg_type(info, BuilderType::Sync)?;
16        if let ArgType::Plain(plain_type) = arg_type {
17            // No fancy builder function, we can just move the value directly into the struct.
18            params.push(quote! { #field_name: #plain_type });
19        } else if let ArgType::TraitBound(bound_type) = arg_type {
20            // Trait bounds are much trickier. We need a special syntax to accept them in the
21            // constructor, and generic parameters need to be added to the builder struct to make
22            // it work.
23            let builder_name = field.builder_name();
24            params.push(quote! { #builder_name : impl #bound_type });
25            let mut builder_args = Vec::new();
26            for (_, borrow) in field.borrows.iter().enumerate() {
27                let borrowed_name = &info.fields[borrow.index].name;
28                if borrow.mutable {
29                    builder_args.push(quote! { &mut #borrowed_name });
30                } else {
31                    builder_args.push(quote! { &#borrowed_name });
32                }
33            }
34            code.push(quote! { let #field_name = #builder_name (#(#builder_args),*); });
35        }
36        if field.is_mutably_borrowed() {
37            code.push(quote! { let mut #field_name = #field_name; });
38        } else {
39            code.push(quote! { let #field_name = #field_name; });
40            value_consumers.push(quote! { #field_name: &#field_name });
41        }
42    }
43    for (_ty, ident) in info.generic_consumers() {
44        template_consumers.push(quote! { #ident: ::core::marker::PhantomData });
45    }
46    let generic_params = info.generic_params();
47    let where_clause = &info.generics.where_clause;
48    let borrowed_generic_params_inferred = info.borrowed_generic_params_inferred();
49    Ok(quote! {
50        fn check_if_okay_according_to_checkers<#generic_params>(
51            #(#params,)*
52        )
53        #where_clause
54        {
55            #(#code;)*
56            BorrowedFields::#borrowed_generic_params_inferred {
57                #(#value_consumers,)*
58                #(#template_consumers,)*
59            };
60        }
61    })
62}
ouroboros_macro/generate/summon_checker.rs

ouroboros_macro/generate/
summon_checker.rs
