channel.c: refactor spaghetti code

channel.c: WIP remove redundant method check and added FUNC_ATTR_NONNULL_ALL macro

channel.c channel_defs.h helpers.c: added Error field to RequestEvent, added no_op handler func

channel.c: use const char* instead of string and cleanup

channel.c; channel_defs.h; helpers.c: removed error from event again; send errors directly to the channel without using handlers and events

channel.c: fixed memory leak and lint errors

api/private/dispatch.c; api/vim.c; msgpack_rpc/channel.c msgpack_rpc/helpers.c added Error* field to msgpack_get_handler_for; further refactored channel.c

channel.c:323 changed order of evaluation in if statement

channel.c: removed superflous whitespace

dispatch.c: review comment

src/nvim/api/private/dispatch.c

@@ -32,16 +32,19 @@ static void msgpack_rpc_add_method_handler(String method,
 /// @param name API method name
 /// @param name_len name size (includes terminating NUL)
 MsgpackRpcRequestHandler msgpack_rpc_get_handler_for(const char *name,
-                                                     size_t name_len)
+                                                     size_t name_len,
+                                                     Error *error)
 {
   String m = { .data = (char *)name, .size = name_len };
   MsgpackRpcRequestHandler rv =
     map_get(String, MsgpackRpcRequestHandler)(methods, m);
 
   if (!rv.fn) {
-    rv.fn = msgpack_rpc_handle_missing_method;
+    String method_name = m.size > 0 ?
+      m : cstr_as_string("<empty>");
+    api_set_error(error, kErrorTypeException, "Invalid method: %s",
+                  method_name);
   }
-
   return rv;
 }
 

src/nvim/api/vim.c

@@ -1162,11 +1162,12 @@ Array nvim_call_atomic(uint64_t channel_id, Array calls, Error *err)
     }
     Array args = call.items[1].data.array;
 
-    MsgpackRpcRequestHandler handler = msgpack_rpc_get_handler_for(name.data,
+    MsgpackRpcRequestHandler handler =
-                                                                   name.size);
+        msgpack_rpc_get_handler_for(name.data,
-    if (handler.fn == msgpack_rpc_handle_missing_method) {
+                                    name.size,
-      api_set_error(&nested_error, kErrorTypeException, "Invalid method: %s",
+                                    &nested_error);
-                    name.size > 0 ? name.data : "<empty>");
+
+    if (ERROR_SET(&nested_error)) {
       break;
     }
     Object result = handler.fn(channel_id, args, &nested_error);

src/nvim/msgpack_rpc/channel.c

@@ -287,7 +287,6 @@ static void parse_msgpack(Channel *channel)
   }
 }
 
-
 static void handle_request(Channel *channel, msgpack_object *request)
   FUNC_ATTR_NONNULL_ALL
 {
@@ -313,27 +312,24 @@ static void handle_request(Channel *channel, msgpack_object *request)
     return;
   }
 
-  // Retrieve the request handler
   MsgpackRpcRequestHandler handler;
-  Array args = ARRAY_DICT_INIT;
   msgpack_object *method = msgpack_rpc_method(request);
+  handler = msgpack_rpc_get_handler_for(method->via.bin.ptr,
+                                        method->via.bin.size,
+                                        &error);
 
-  if (method) {
+  // check method arguments
-    handler = msgpack_rpc_get_handler_for(method->via.bin.ptr,
+  Array args = ARRAY_DICT_INIT;
-                                          method->via.bin.size);
+  if (!ERROR_SET(&error)
-    if (handler.fn == msgpack_rpc_handle_missing_method) {
+      && !msgpack_rpc_to_array(msgpack_rpc_args(request), &args)) {
-      String m = method->via.bin.size > 0
+    api_set_error(&error, kErrorTypeException, "Invalid method arguments");
-        ? cbuf_to_string(method->via.bin.ptr, method->via.bin.size)
+  }
-        : cstr_to_string("<empty>");
+
-      ADD(args, STRING_OBJ(m));
+  if (ERROR_SET(&error)) {
-      handler.async = true;
+    send_error(channel, request_id, error.msg);
-    } else if (!msgpack_rpc_to_array(msgpack_rpc_args(request), &args)) {
+    api_clear_error(&error);
-      handler.fn = msgpack_rpc_handle_invalid_arguments;
+    api_free_array(args);
-      handler.async = true;
+    return;
-    }
-  } else {
-    handler.fn = msgpack_rpc_handle_missing_method;
-    handler.async = true;
   }
 
   RequestEvent *evdata = xmalloc(sizeof(RequestEvent));

src/nvim/msgpack_rpc/helpers.c

@@ -488,25 +488,6 @@ void msgpack_rpc_from_dictionary(Dictionary result, msgpack_packer *res)
   }
 }
 
-/// Handler executed when an invalid method name is passed
-Object msgpack_rpc_handle_missing_method(uint64_t channel_id,
-                                         Array args,
-                                         Error *error)
-{
-  api_set_error(error, kErrorTypeException, "Invalid method: %s",
-                args.size > 0 ? args.items[0].data.string.data : "?");
-  return NIL;
-}
-
-/// Handler executed when malformated arguments are passed
-Object msgpack_rpc_handle_invalid_arguments(uint64_t channel_id,
-                                            Array args,
-                                            Error *error)
-{
-  api_set_error(error, kErrorTypeException, "Invalid method arguments");
-  return NIL;
-}
-
 /// Serializes a msgpack-rpc request or notification(id == 0)
 void msgpack_rpc_serialize_request(uint64_t request_id,
                                    const String method,