Checkpoint for gRPC implementation

codegen/src/generator.rs

@@ -439,14 +439,15 @@ fn write_message(msg_proto: &DescriptorProto, output: &mut String) {
     output.push_str("}\n\n");
 
     output.push_str(&format!("impl roto_runtime::RotoOwned for Owned{} {{\n", msg_name));
+    output.push_str(&format!("    type Reader<'a> = {}<'a>;\n", msg_name));
     output.push_str(&format!("    fn reader(&self) -> {}<'_> {{\n", msg_name));
     output.push_str(&format!("        {}::new(&self.data).expect(\"failed to create reader\")\n", msg_name));
     output.push_str("    }\n");
     output.push_str("}\n\n");
 
     output.push_str(&format!("impl roto_runtime::RotoMessage for Owned{} {{\n", msg_name));
-    output.push_str("    fn decode(buf: bytes::Bytes) -> Self {\n");
-    output.push_str(&format!("        Owned{} {{ data: buf }}\n", msg_name));
+    output.push_str("    fn decode(buf: bytes::Bytes) -> roto_runtime::Result<Self> {\n");
+    output.push_str(&format!("        Ok(Owned{} {{ data: buf }})\n", msg_name));
     output.push_str("    }\n\n");
     output.push_str("    fn bytes(&self) -> bytes::Bytes {\n");
     output.push_str("        self.data.clone()\n");
@@ -675,7 +676,7 @@ fn write_service(svc_proto: &ServiceDescriptorProto, output: &mut String) {
         };
 
         output.push_str(&format!(
-            "    async fn {}(&self, request: {}) -> Result<{}, Status>;\n",
+            "    async fn {}(&self, request: {}) -> std::result::Result<{}, Status>;\n",
             method_name, req_type, resp_type
         ));
     }