services/utils/service_enclave_utils/proc_macro/src/lib.rs

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// distributed with this work for additional information
// regarding copyright ownership.  The ASF licenses this file
// to you under the Apache License, Version 2.0 (the
// "License"); you may not use this file except in compliance
// with the License.  You may obtain a copy of the License at
//
//   http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing,
// software distributed under the License is distributed on an
// "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
// KIND, either express or implied.  See the License for the
// specific language governing permissions and limitations
// under the License.

extern crate proc_macro;
use proc_macro2::{Ident, Span};
use quote::quote;
use syn::parse_macro_input;
use syn::ItemStruct;

use proc_macro::TokenStream;

#[proc_macro_attribute]
pub fn teaclave_service(attr: TokenStream, input: TokenStream) -> TokenStream {
    let attr_str = attr.to_string();
    let splits: Vec<&str> = attr_str.split(',').map(|s| s.trim()).collect();
    let crate_name = Ident::new(splits[0], Span::call_site());
    let crate_name_proto = Ident::new(&format!("{}_proto", crate_name), Span::call_site());
    let trait_name = splits[1];
    let trait_name_ident = Ident::new(trait_name, Span::call_site());
    let request = Ident::new(&format!("{}Request", trait_name), Span::call_site());
    let response = Ident::new(&format!("{}Response", trait_name), Span::call_site());

    let f = parse_macro_input!(input as ItemStruct);
    let struct_ident = &f.ident;
    let q = quote!(
        #f

        impl teaclave_rpc::TeaclaveService<teaclave_proto::#crate_name_proto::#request, teaclave_proto::#crate_name_proto::#response>
            for #struct_ident
        {
            fn handle_request(
                &self,
                request: teaclave_rpc::Request<teaclave_proto::#crate_name_proto::#request>,
            ) -> std::result::Result<teaclave_proto::#crate_name_proto::#response, teaclave_types::TeaclaveServiceResponseError> {
                use teaclave_proto::#crate_name_proto::#trait_name_ident;
                use log::trace;
                trace!("Dispatching request.");
                self.dispatch(request)
            }
        }
    );
    q.into()
}