95 lines
3.2 KiB
Rust
95 lines
3.2 KiB
Rust
mod models;
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use models::{FieldAttributeBuilder, TypeAttributeBuilder};
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use quote::quote;
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use syn::{Data, DeriveInput, Meta};
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use super::TraitHandler;
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use crate::Trait;
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pub(crate) struct CopyHandler;
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impl TraitHandler for CopyHandler {
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#[inline]
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fn trait_meta_handler(
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ast: &DeriveInput,
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token_stream: &mut proc_macro2::TokenStream,
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traits: &[Trait],
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meta: &Meta,
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) -> syn::Result<()> {
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#[cfg(feature = "Clone")]
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let contains_clone = traits.contains(&Trait::Clone);
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#[cfg(not(feature = "Clone"))]
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let contains_clone = false;
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let type_attribute = TypeAttributeBuilder {
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enable_flag: true,
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enable_bound: !contains_clone,
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}
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.build_from_copy_meta(meta)?;
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let mut field_types = vec![];
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// if `contains_clone` is true, the implementation is handled by the `Clone` attribute, and field attributes is also handled by the `Clone` attribute
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if !contains_clone {
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match &ast.data {
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Data::Struct(data) => {
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for field in data.fields.iter() {
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field_types.push(&field.ty);
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let _ =
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FieldAttributeBuilder.build_from_attributes(&field.attrs, traits)?;
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}
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},
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Data::Enum(data) => {
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for variant in data.variants.iter() {
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let _ = TypeAttributeBuilder {
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enable_flag: false, enable_bound: false
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}
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.build_from_attributes(&variant.attrs, traits)?;
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for field in variant.fields.iter() {
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field_types.push(&field.ty);
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let _ = FieldAttributeBuilder
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.build_from_attributes(&field.attrs, traits)?;
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}
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}
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},
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Data::Union(data) => {
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for field in data.fields.named.iter() {
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field_types.push(&field.ty);
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let _ =
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FieldAttributeBuilder.build_from_attributes(&field.attrs, traits)?;
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}
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},
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}
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let ident = &ast.ident;
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let bound =
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type_attribute.bound.into_where_predicates_by_generic_parameters_check_types(
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&ast.generics.params,
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&syn::parse2(quote!(::core::marker::Copy)).unwrap(),
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&field_types,
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&[quote! {::core::clone::Clone}],
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);
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let mut generics = ast.generics.clone();
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let where_clause = generics.make_where_clause();
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for where_predicate in bound {
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where_clause.predicates.push(where_predicate);
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}
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let (impl_generics, ty_generics, where_clause) = generics.split_for_impl();
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token_stream.extend(quote! {
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impl #impl_generics ::core::marker::Copy for #ident #ty_generics #where_clause {
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}
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});
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}
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Ok(())
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}
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}
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