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| 1 | +use super::models::BuilderGenCtx; |
| 2 | +use crate::parsing::ItemSigConfig; |
| 3 | +use crate::util::prelude::*; |
| 4 | + |
| 5 | +pub(super) struct GenericSettersCtx<'a> { |
| 6 | + base: &'a BuilderGenCtx, |
| 7 | + config: &'a ItemSigConfig<String>, |
| 8 | +} |
| 9 | + |
| 10 | +impl<'a> GenericSettersCtx<'a> { |
| 11 | + pub(super) fn new(base: &'a BuilderGenCtx, config: &'a ItemSigConfig<String>) -> Self { |
| 12 | + Self { base, config } |
| 13 | + } |
| 14 | + |
| 15 | + pub(super) fn generic_setter_methods(&self) -> Result<TokenStream> { |
| 16 | + let methods = self |
| 17 | + .base |
| 18 | + .generics |
| 19 | + .decl_without_defaults |
| 20 | + .iter() |
| 21 | + .enumerate() |
| 22 | + .filter_map(|(index, param)| { |
| 23 | + // Only generate setters for type parameters, not lifetimes or const generics |
| 24 | + match param { |
| 25 | + syn::GenericParam::Type(type_param) => { |
| 26 | + Some(self.generic_setter_method(index, &type_param.ident)) |
| 27 | + } |
| 28 | + _ => None, |
| 29 | + } |
| 30 | + }) |
| 31 | + .collect::<Result<Vec<_>>>()?; |
| 32 | + |
| 33 | + Ok(quote! { |
| 34 | + #(#methods)* |
| 35 | + }) |
| 36 | + } |
| 37 | + |
| 38 | + fn generic_setter_method( |
| 39 | + &self, |
| 40 | + param_index: usize, |
| 41 | + param_ident: &syn::Ident, |
| 42 | + ) -> Result<TokenStream> { |
| 43 | + let builder_ident = &self.base.builder_type.ident; |
| 44 | + let state_var = &self.base.state_var; |
| 45 | + let where_clause = &self.base.generics.where_clause; |
| 46 | + |
| 47 | + let method_name = self.method_name(param_ident)?; |
| 48 | + |
| 49 | + let vis = self |
| 50 | + .config |
| 51 | + .vis |
| 52 | + .as_ref() |
| 53 | + .map(|v| &v.value) |
| 54 | + .unwrap_or(&self.base.builder_type.vis); |
| 55 | + |
| 56 | + let docs = self.method_docs(param_ident); |
| 57 | + |
| 58 | + // Build the generic arguments for the output type, where the current parameter |
| 59 | + // is replaced with a new type variable |
| 60 | + let new_type_var = format_ident!("{}2", param_ident); |
| 61 | + let output_generic_args = self |
| 62 | + .base |
| 63 | + .generics |
| 64 | + .args |
| 65 | + .iter() |
| 66 | + .enumerate() |
| 67 | + .map(|(i, arg)| { |
| 68 | + if i == param_index { |
| 69 | + quote!(#new_type_var) |
| 70 | + } else { |
| 71 | + quote!(#arg) |
| 72 | + } |
| 73 | + }) |
| 74 | + .collect::<Vec<_>>(); |
| 75 | + |
| 76 | + let new_type_param: syn::GenericParam = syn::parse_quote!(#new_type_var); |
| 77 | + |
| 78 | + let where_clause = where_clause.as_ref().map(|wc| quote!(#wc)); |
| 79 | + |
| 80 | + // Check which named members use this generic parameter |
| 81 | + let named_member_conversions = self |
| 82 | + .base |
| 83 | + .named_members() |
| 84 | + .enumerate() |
| 85 | + .map(|(idx, member)| { |
| 86 | + let uses_param = self.member_uses_generic_param(member, param_ident); |
| 87 | + if uses_param { |
| 88 | + // Field uses the generic parameter, so create a new None |
| 89 | + quote!(::core::option::Option::None) |
| 90 | + } else { |
| 91 | + // Field doesn't use the generic parameter, so move it from the tuple |
| 92 | + let index = syn::Index::from(idx); |
| 93 | + quote!(named.#index) |
| 94 | + } |
| 95 | + }) |
| 96 | + .collect::<Vec<_>>(); |
| 97 | + |
| 98 | + let receiver_field = self.base.receiver().map(|receiver| { |
| 99 | + let ident = &receiver.field_ident; |
| 100 | + quote!(#ident: self.#ident,) |
| 101 | + }); |
| 102 | + |
| 103 | + let start_fn_fields = self.base.start_fn_args().map(|member| { |
| 104 | + let ident = &member.ident; |
| 105 | + quote!(#ident: self.#ident,) |
| 106 | + }); |
| 107 | + |
| 108 | + let custom_fields = self.base.custom_fields().map(|field| { |
| 109 | + let ident = &field.ident; |
| 110 | + quote!(#ident: self.#ident,) |
| 111 | + }); |
| 112 | + |
| 113 | + Ok(quote! { |
| 114 | + #(#docs)* |
| 115 | + #[inline(always)] |
| 116 | + #vis fn #method_name<#new_type_param>( |
| 117 | + self |
| 118 | + ) -> #builder_ident<#(#output_generic_args,)* #state_var> |
| 119 | + #where_clause |
| 120 | + { |
| 121 | + let named = self.__unsafe_private_named; |
| 122 | + |
| 123 | + #builder_ident { |
| 124 | + __unsafe_private_phantom: ::core::marker::PhantomData, |
| 125 | + #receiver_field |
| 126 | + #(#start_fn_fields)* |
| 127 | + #(#custom_fields)* |
| 128 | + __unsafe_private_named: ( |
| 129 | + #(#named_member_conversions,)* |
| 130 | + ), |
| 131 | + } |
| 132 | + } |
| 133 | + }) |
| 134 | + } |
| 135 | + |
| 136 | + /// Check if a member's type uses a specific generic parameter |
| 137 | + fn member_uses_generic_param( |
| 138 | + &self, |
| 139 | + member: &super::NamedMember, |
| 140 | + param_ident: &syn::Ident, |
| 141 | + ) -> bool { |
| 142 | + let member_ty = member.underlying_norm_ty(); |
| 143 | + self.type_uses_generic_param(member_ty, param_ident) |
| 144 | + } |
| 145 | + |
| 146 | + /// Recursively check if a type uses a specific generic parameter |
| 147 | + fn type_uses_generic_param(&self, ty: &syn::Type, param_ident: &syn::Ident) -> bool { |
| 148 | + use syn::visit::Visit; |
| 149 | + |
| 150 | + struct GenericParamVisitor<'a> { |
| 151 | + param_ident: &'a syn::Ident, |
| 152 | + found: bool, |
| 153 | + } |
| 154 | + |
| 155 | + impl<'ast> Visit<'ast> for GenericParamVisitor<'_> { |
| 156 | + fn visit_path(&mut self, path: &'ast syn::Path) { |
| 157 | + // Check if the path is the generic parameter we're looking for |
| 158 | + if path.is_ident(self.param_ident) { |
| 159 | + self.found = true; |
| 160 | + return; |
| 161 | + } |
| 162 | + |
| 163 | + // Continue visiting the rest of the path |
| 164 | + syn::visit::visit_path(self, path); |
| 165 | + } |
| 166 | + } |
| 167 | + |
| 168 | + let mut visitor = GenericParamVisitor { |
| 169 | + param_ident, |
| 170 | + found: false, |
| 171 | + }; |
| 172 | + visitor.visit_type(ty); |
| 173 | + visitor.found |
| 174 | + } |
| 175 | + |
| 176 | + fn method_name(&self, param_ident: &syn::Ident) -> Result<syn::Ident> { |
| 177 | + let param_name = param_ident.to_string(); |
| 178 | + let param_name_lower = param_name.to_lowercase(); |
| 179 | + |
| 180 | + let name_pattern = self |
| 181 | + .config |
| 182 | + .name |
| 183 | + .as_ref() |
| 184 | + .map(|n| n.value.as_str()) |
| 185 | + .unwrap_or("conv_{}"); |
| 186 | + |
| 187 | + let method_name = name_pattern.replace("{}", ¶m_name_lower); |
| 188 | + |
| 189 | + Ok(syn::Ident::new(&method_name, param_ident.span())) |
| 190 | + } |
| 191 | + |
| 192 | + fn method_docs(&self, param_ident: &syn::Ident) -> Vec<syn::Attribute> { |
| 193 | + // If custom docs are provided, use them |
| 194 | + if let Some(ref docs) = self.config.docs { |
| 195 | + return docs.value.clone(); |
| 196 | + } |
| 197 | + |
| 198 | + // Otherwise, generate default documentation |
| 199 | + let param_name = param_ident.to_string(); |
| 200 | + let doc = format!( |
| 201 | + "Convert the `{}` generic parameter to a different type.\n\ |
| 202 | + \n\ |
| 203 | + This method allows changing the type of the `{}` parameter on the builder, \ |
| 204 | + which is useful when you need to build up values with different types at \ |
| 205 | + different stages of construction.", |
| 206 | + param_name, param_name |
| 207 | + ); |
| 208 | + |
| 209 | + vec![syn::parse_quote!(#[doc = #doc])] |
| 210 | + } |
| 211 | +} |
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