Add ExpandAttribute handler

scarb/src/ops/proc_macro_server/methods/expand_attribute.rs

@@ -0,0 +1,29 @@
+use crate::{
+    compiler::plugin::proc_macro::{ExpansionKind, ProcMacroHost},
+    ops::proc_macro_server::json_rpc::Handler,
+};
+use anyhow::Result;
+use scarb_proc_macro_server_types::methods::{expand::ExpandAttribute, ProcMacroResult};
+use std::sync::Arc;
+
+impl Handler for ExpandAttribute {
+    fn handle(proc_macros: Arc<ProcMacroHost>, params: Self::Params) -> Result<Self::Response> {
+        let instance = proc_macros
+            .macros()
+            .into_iter()
+            .find(|e| {
+                e.get_expansions()
+                    .iter()
+                    .filter(|expansion| expansion.kind == ExpansionKind::Attr)
+                    .any(|expansion| expansion.name == params.attr)
+            })
+            .unwrap();
+
+        let result = instance.generate_code(params.attr.into(), params.args, params.item);
+
+        Ok(ProcMacroResult {
+            token_stream: result.token_stream,
+            diagnostics: result.diagnostics,
+        })
+    }
+}

scarb/src/ops/proc_macro_server/methods/mod.rs

@@ -1 +1,2 @@
 pub mod defined_macros;
+pub mod expand_attribute;

scarb/src/ops/proc_macro_server/mod.rs

@@ -8,6 +8,7 @@ use crossbeam_channel::{Receiver, Sender};
 use json_rpc::Handler;
 use scarb_proc_macro_server_types::jsonrpc::{ResponseError, RpcRequest, RpcResponse};
 use scarb_proc_macro_server_types::methods::defined_macros::DefinedMacros;
+use scarb_proc_macro_server_types::methods::expand::ExpandAttribute;
 use scarb_proc_macro_server_types::methods::Method;
 use serde_json::Value;
 
@@ -71,6 +72,9 @@ fn handle_requests(
 fn route_request(proc_macros: Arc<ProcMacroHost>, request: RpcRequest) -> Result<Value> {
     match request.method.as_str() {
         DefinedMacros::METHOD => run_handler::<DefinedMacros>(proc_macros.clone(), request.value),
+        ExpandAttribute::METHOD => {
+            run_handler::<ExpandAttribute>(proc_macros.clone(), request.value)
+        }
         _ => Err(anyhow!("method not found")),
     }
 }