1 | use proc_macro2::TokenStream; |
2 | use quote::{quote, ToTokens}; |
3 | use syn::Ident; |
4 | |
5 | use crate::codegen::{ExtractAttribute, OuterFromImpl, TraitImpl}; |
6 | use crate::options::ForwardAttrs; |
7 | use crate::util::PathList; |
8 | |
9 | pub struct FromTypeParamImpl<'a> { |
10 | pub base: TraitImpl<'a>, |
11 | pub ident: Option<&'a Ident>, |
12 | pub attrs: Option<&'a Ident>, |
13 | pub bounds: Option<&'a Ident>, |
14 | pub default: Option<&'a Ident>, |
15 | pub attr_names: &'a PathList, |
16 | pub forward_attrs: Option<&'a ForwardAttrs>, |
17 | pub from_ident: bool, |
18 | } |
19 | |
20 | impl<'a> ToTokens for FromTypeParamImpl<'a> { |
21 | fn to_tokens(&self, tokens: &mut TokenStream) { |
22 | let input = self.param_name(); |
23 | |
24 | let error_declaration = self.base.declare_errors(); |
25 | let grab_attrs = self.extractor(); |
26 | let require_fields = self.base.require_fields(); |
27 | let error_check = self.base.check_errors(); |
28 | |
29 | let default = if self.from_ident { |
30 | quote!(let __default: Self = ::darling::export::From::from(#input.ident.clone());) |
31 | } else { |
32 | self.base.fallback_decl() |
33 | }; |
34 | |
35 | let passed_ident = self |
36 | .ident |
37 | .as_ref() |
38 | .map(|i| quote!(#i: #input.ident.clone(),)); |
39 | let passed_attrs = self.attrs.as_ref().map(|i| quote!(#i: __fwd_attrs,)); |
40 | let passed_bounds = self |
41 | .bounds |
42 | .as_ref() |
43 | .map(|i| quote!(#i: #input.bounds.clone().into_iter().collect::<Vec<_>>(),)); |
44 | let passed_default = self |
45 | .default |
46 | .as_ref() |
47 | .map(|i| quote!(#i: #input.default.clone(),)); |
48 | let initializers = self.base.initializers(); |
49 | |
50 | let post_transform = self.base.post_transform_call(); |
51 | |
52 | self.wrap( |
53 | quote! { |
54 | fn from_type_param(#input: &::darling::export::syn::TypeParam) -> ::darling::Result<Self> { |
55 | #error_declaration |
56 | |
57 | #grab_attrs |
58 | |
59 | #require_fields |
60 | |
61 | #error_check |
62 | |
63 | #default |
64 | |
65 | ::darling::export::Ok(Self { |
66 | #passed_ident |
67 | #passed_bounds |
68 | #passed_default |
69 | #passed_attrs |
70 | #initializers |
71 | }) #post_transform |
72 | } |
73 | }, |
74 | tokens, |
75 | ); |
76 | } |
77 | } |
78 | |
79 | impl<'a> ExtractAttribute for FromTypeParamImpl<'a> { |
80 | fn attr_names(&self) -> &PathList { |
81 | self.attr_names |
82 | } |
83 | |
84 | fn forwarded_attrs(&self) -> Option<&ForwardAttrs> { |
85 | self.forward_attrs |
86 | } |
87 | |
88 | fn param_name(&self) -> TokenStream { |
89 | quote!(__type_param) |
90 | } |
91 | |
92 | fn core_loop(&self) -> TokenStream { |
93 | self.base.core_loop() |
94 | } |
95 | |
96 | fn local_declarations(&self) -> TokenStream { |
97 | self.base.local_declarations() |
98 | } |
99 | } |
100 | |
101 | impl<'a> OuterFromImpl<'a> for FromTypeParamImpl<'a> { |
102 | fn trait_path(&self) -> syn::Path { |
103 | path!(::darling::FromTypeParam) |
104 | } |
105 | |
106 | fn trait_bound(&self) -> syn::Path { |
107 | path!(::darling::FromMeta) |
108 | } |
109 | |
110 | fn base(&'a self) -> &'a TraitImpl<'a> { |
111 | &self.base |
112 | } |
113 | } |
114 | |