educe/trait_handlers/partial_eq/
partial_eq_struct.rs

1use quote::quote;
2use syn::{Data, DeriveInput, Meta, Type};
3
4use super::{
5    models::{FieldAttributeBuilder, TypeAttributeBuilder},
6    TraitHandler,
7};
8use crate::{common::ident_index::IdentOrIndex, Trait};
9
10pub(crate) struct PartialEqStructHandler;
11
12impl TraitHandler for PartialEqStructHandler {
13    #[inline]
14    fn trait_meta_handler(
15        ast: &DeriveInput,
16        token_stream: &mut proc_macro2::TokenStream,
17        traits: &[Trait],
18        meta: &Meta,
19    ) -> syn::Result<()> {
20        let type_attribute =
21            TypeAttributeBuilder {
22                enable_flag: true, enable_unsafe: false, enable_bound: true
23            }
24            .build_from_partial_eq_meta(meta)?;
25
26        let mut partial_eq_types: Vec<&Type> = Vec::new();
27
28        let mut eq_token_stream = proc_macro2::TokenStream::new();
29
30        if let Data::Struct(data) = &ast.data {
31            for (index, field) in data.fields.iter().enumerate() {
32                let field_attribute = FieldAttributeBuilder {
33                    enable_ignore: true,
34                    enable_method: true,
35                }
36                .build_from_attributes(&field.attrs, traits)?;
37
38                if field_attribute.ignore {
39                    continue;
40                }
41
42                let field_name = IdentOrIndex::from_ident_with_index(field.ident.as_ref(), index);
43
44                if let Some(method) = field_attribute.method {
45                    eq_token_stream.extend(quote! {
46                        if !#method(&self.#field_name, &other.#field_name) {
47                            return false;
48                        }
49                    });
50                } else {
51                    let ty = &field.ty;
52
53                    partial_eq_types.push(ty);
54
55                    eq_token_stream.extend(quote! {
56                        if ::core::cmp::PartialEq::ne(&self.#field_name, &other.#field_name) {
57                            return false;
58                        }
59                    });
60                }
61            }
62        }
63
64        let ident = &ast.ident;
65
66        let bound = type_attribute.bound.into_where_predicates_by_generic_parameters_check_types(
67            &ast.generics.params,
68            &syn::parse2(quote!(::core::cmp::PartialEq)).unwrap(),
69            &partial_eq_types,
70            &[],
71        );
72
73        let mut generics = ast.generics.clone();
74        let where_clause = generics.make_where_clause();
75
76        for where_predicate in bound {
77            where_clause.predicates.push(where_predicate);
78        }
79
80        let (impl_generics, ty_generics, where_clause) = generics.split_for_impl();
81
82        token_stream.extend(quote! {
83            impl #impl_generics ::core::cmp::PartialEq for #ident #ty_generics #where_clause {
84                #[inline]
85                fn eq(&self, other: &Self) -> bool {
86                    #eq_token_stream
87
88                    true
89                }
90            }
91        });
92
93        #[cfg(feature = "Eq")]
94        if traits.contains(&Trait::Eq) {
95            token_stream.extend(quote! {
96                impl #impl_generics ::core::cmp::Eq for #ident #ty_generics #where_clause {
97                }
98            });
99        }
100
101        Ok(())
102    }
103}
educe/trait_handlers/partial_eq/partial_eq_struct.rs

educe/trait_handlers/partial_eq/
partial_eq_struct.rs
