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#![deny(
warnings,
missing_debug_implementations,
missing_copy_implementations,
trivial_casts,
trivial_numeric_casts,
unsafe_code,
unstable_features,
unused_import_braces,
unused_qualifications
)]
extern crate proc_macro;
use crate::proc_macro::TokenStream;
use quote::quote;
use syn;
#[proc_macro_derive(IntoMetadataKV)]
pub fn metadata_kv_derive(input: TokenStream) -> TokenStream {
let ast: syn::DeriveInput = syn::parse(input).unwrap();
match ast.data {
syn::Data::Struct(fields) => impl_metadata_kv(ast.ident, fields),
_ => panic!("#[derive(IntoMetadataKV)] is only defined for structs"),
}
}
fn impl_metadata_kv(name: syn::Ident, data_struct: syn::DataStruct) -> TokenStream {
let md_fields: Vec<_> = data_struct
.fields
.iter()
.filter_map(|field| field.ident.as_ref())
.map(|field_name| {
quote! {
concourse_resource::internal::KV {
name: String::from(stringify!(#field_name)),
value: serde_json::to_string(&self.#field_name).unwrap()
}
}
})
.collect();
let gen = quote! {
impl IntoMetadataKV for #name {
fn into_metadata_kv(self) -> Vec<concourse_resource::internal::KV> {
vec![#(#md_fields,)*]
}
}
};
gen.into()
}