ddce22b614
# Objective Reduce from scratch build time. ## Solution Reduce the size of the critical path by removing dependencies between crates where not necessary. For `cargo check --no-default-features` this reduced build time from ~51s to ~45s. For some commits I am not completely sure if the tradeoff between build time reduction and convenience caused by the commit is acceptable. If not, I can drop them.
41 lines
1.3 KiB
Rust
41 lines
1.3 KiB
Rust
use proc_macro::{Span, TokenStream};
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use quote::quote;
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use syn::{parse_macro_input, Data, DeriveInput};
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pub fn derive_enum_variant_meta(input: TokenStream) -> TokenStream {
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let ast = parse_macro_input!(input as DeriveInput);
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let variants = match &ast.data {
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Data::Enum(v) => &v.variants,
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_ => {
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return syn::Error::new(Span::call_site().into(), "Only enums are supported")
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.into_compile_error()
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.into()
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}
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};
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let generics = ast.generics;
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let (impl_generics, ty_generics, where_clause) = generics.split_for_impl();
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let struct_name = &ast.ident;
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let idents = variants.iter().map(|v| &v.ident);
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let names = variants.iter().map(|v| v.ident.to_string());
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let indices = 0..names.len();
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TokenStream::from(quote! {
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impl #impl_generics #struct_name #ty_generics #where_clause {
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pub fn enum_variant_index(&self) -> usize {
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match self {
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#(#struct_name::#idents {..} => #indices,)*
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}
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}
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pub fn enum_variant_name(&self) -> &'static str {
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static variants: &[&str] = &[
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#(#names,)*
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];
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let index = self.enum_variant_index();
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variants[index]
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}
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}
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})
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}
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