msgpack: Replace FUNC_ATTR_DEFERRED by FUNC_ATTR_ASYNC

API functions exposed via msgpack-rpc now fall into two categories:

- async functions, which are executed as soon as the request is parsed
- sync functions, which are invoked in nvim main loop when processing the
  `K_EVENT special key

Only a few functions which can be safely executed in any context are marked as
async.

scripts/msgpack-gen.lua

@@ -34,8 +34,8 @@ c_params = Ct(c_void + c_param_list)
 c_proto = Ct(
   Cg(c_type, 'return_type') * Cg(c_id, 'name') *
   fill * P('(') * fill * Cg(c_params, 'parameters') * fill * P(')') *
-  Cg(Cc(false), 'deferred') *
-  (fill * Cg((P('FUNC_ATTR_DEFERRED') * Cc(true)), 'deferred') ^ -1) *
+  Cg(Cc(false), 'async') *
+  (fill * Cg((P('FUNC_ATTR_ASYNC') * Cc(true)), 'async') ^ -1) *
   fill * P(';')
   )
 grammar = Ct((c_proto + c_comment + c_preproc + ws) ^ 1)
@@ -279,7 +279,7 @@ for i = 1, #functions do
                '(String) {.data = "'..fn.name..'", '..
                '.size = sizeof("'..fn.name..'") - 1}, '..
                '(MsgpackRpcRequestHandler) {.fn = handle_'..  fn.name..
-               ', .defer = '..tostring(fn.deferred)..'});\n')
+               ', .async = '..tostring(fn.async)..'});\n')
 
   if #fn.name > max_fname_len then
     max_fname_len = #fn.name

src/nvim/api/buffer.c

@@ -70,7 +70,6 @@ String buffer_get_line(Buffer buffer, Integer index, Error *err)
 /// @param line The new line.
 /// @param[out] err Details of an error that may have occurred
 void buffer_set_line(Buffer buffer, Integer index, String line, Error *err)
-  FUNC_ATTR_DEFERRED
 {
   Object l = STRING_OBJ(line);
   Array array = {.items = &l, .size = 1};
@@ -83,7 +82,6 @@ void buffer_set_line(Buffer buffer, Integer index, String line, Error *err)
 /// @param index The line index
 /// @param[out] err Details of an error that may have occurred
 void buffer_del_line(Buffer buffer, Integer index, Error *err)
-  FUNC_ATTR_DEFERRED
 {
   Array array = ARRAY_DICT_INIT;
   buffer_set_line_slice(buffer, index, index, true, true, array, err);
@@ -171,7 +169,6 @@ void buffer_set_line_slice(Buffer buffer,
                       Boolean include_end,
                       ArrayOf(String) replacement,
                       Error *err)
-  FUNC_ATTR_DEFERRED
 {
   buf_T *buf = find_buffer_by_handle(buffer, err);
 
@@ -339,7 +336,6 @@ Object buffer_get_var(Buffer buffer, String name, Error *err)
 /// @param[out] err Details of an error that may have occurred
 /// @return The old value
 Object buffer_set_var(Buffer buffer, String name, Object value, Error *err)
-  FUNC_ATTR_DEFERRED
 {
   buf_T *buf = find_buffer_by_handle(buffer, err);
 
@@ -375,7 +371,6 @@ Object buffer_get_option(Buffer buffer, String name, Error *err)
 /// @param value The option value
 /// @param[out] err Details of an error that may have occurred
 void buffer_set_option(Buffer buffer, String name, Object value, Error *err)
-  FUNC_ATTR_DEFERRED
 {
   buf_T *buf = find_buffer_by_handle(buffer, err);
 
@@ -426,7 +421,6 @@ String buffer_get_name(Buffer buffer, Error *err)
 /// @param name The buffer name
 /// @param[out] err Details of an error that may have occurred
 void buffer_set_name(Buffer buffer, String name, Error *err)
-  FUNC_ATTR_DEFERRED
 {
   buf_T *buf = find_buffer_by_handle(buffer, err);
 
@@ -472,7 +466,6 @@ void buffer_insert(Buffer buffer,
                    Integer lnum,
                    ArrayOf(String) lines,
                    Error *err)
-  FUNC_ATTR_DEFERRED
 {
   buffer_set_line_slice(buffer, lnum, lnum, false, true, lines, err);
 }

src/nvim/api/tabpage.c

@@ -62,7 +62,6 @@ Object tabpage_get_var(Tabpage tabpage, String name, Error *err)
 /// @param[out] err Details of an error that may have occurred
 /// @return The tab page handle
 Object tabpage_set_var(Tabpage tabpage, String name, Object value, Error *err)
-  FUNC_ATTR_DEFERRED
 {
   tabpage_T *tab = find_tab_by_handle(tabpage, err);
 

src/nvim/api/vim.c

@@ -37,7 +37,6 @@
 /// @param str The command str
 /// @param[out] err Details of an error that may have occurred
 void vim_command(String str, Error *err)
-  FUNC_ATTR_DEFERRED
 {
   // Run the command
   try_start();
@@ -54,7 +53,6 @@ void vim_command(String str, Error *err)
 /// @see feedkeys()
 /// @see vim_strsave_escape_csi
 void vim_feedkeys(String keys, String mode, Boolean escape_csi)
-  FUNC_ATTR_DEFERRED
 {
   bool remap = true;
   bool insert = false;
@@ -100,6 +98,7 @@ void vim_feedkeys(String keys, String mode, Boolean escape_csi)
 /// @return The number of bytes actually written, which can be lower than
 ///         requested if the buffer becomes full.
 Integer vim_input(String keys)
+  FUNC_ATTR_ASYNC
 {
   return (Integer)input_enqueue(keys);
 }
@@ -143,7 +142,6 @@ String vim_command_output(String str, Error *err)
 /// @param[out] err Details of an error that may have occurred
 /// @return The expanded object
 Object vim_eval(String str, Error *err)
-  FUNC_ATTR_DEFERRED
 {
   Object rv = OBJECT_INIT;
   // Evaluate the expression
@@ -171,7 +169,6 @@ Object vim_eval(String str, Error *err)
 /// @param[out] err Details of an error that may have occurred
 /// @return Result of the function call
 Object vim_call_function(String fname, Array args, Error *err)
-  FUNC_ATTR_DEFERRED
 {
   Object rv = OBJECT_INIT;
   if (args.size > MAX_FUNC_ARGS) {
@@ -312,7 +309,6 @@ String vim_get_current_line(Error *err)
 /// @param line The line contents
 /// @param[out] err Details of an error that may have occurred
 void vim_set_current_line(String line, Error *err)
-  FUNC_ATTR_DEFERRED
 {
   buffer_set_line(curbuf->handle, curwin->w_cursor.lnum - 1, line, err);
 }
@@ -321,7 +317,6 @@ void vim_set_current_line(String line, Error *err)
 ///
 /// @param[out] err Details of an error that may have occurred
 void vim_del_current_line(Error *err)
-  FUNC_ATTR_DEFERRED
 {
   buffer_del_line(curbuf->handle, curwin->w_cursor.lnum - 1, err);
 }
@@ -343,7 +338,6 @@ Object vim_get_var(String name, Error *err)
 /// @param[out] err Details of an error that may have occurred
 /// @return the old value if any
 Object vim_set_var(String name, Object value, Error *err)
-  FUNC_ATTR_DEFERRED
 {
   return dict_set_value(&globvardict, name, value, err);
 }
@@ -374,7 +368,6 @@ Object vim_get_option(String name, Error *err)
 /// @param value The new option value
 /// @param[out] err Details of an error that may have occurred
 void vim_set_option(String name, Object value, Error *err)
-  FUNC_ATTR_DEFERRED
 {
   set_option_to(NULL, SREQ_GLOBAL, name, value, err);
 }
@@ -383,7 +376,6 @@ void vim_set_option(String name, Object value, Error *err)
 ///
 /// @param str The message
 void vim_out_write(String str)
-  FUNC_ATTR_DEFERRED
 {
   write_msg(str, false);
 }
@@ -392,7 +384,6 @@ void vim_out_write(String str)
 ///
 /// @param str The message
 void vim_err_write(String str)
-  FUNC_ATTR_DEFERRED
 {
   write_msg(str, true);
 }
@@ -402,7 +393,6 @@ void vim_err_write(String str)
 ///
 /// @param str The message
 void vim_report_error(String str)
-  FUNC_ATTR_DEFERRED
 {
   vim_err_write(str);
   vim_err_write((String) {.data = "\n", .size = 1});
@@ -442,7 +432,6 @@ Buffer vim_get_current_buffer(void)
 /// @param id The buffer handle
 /// @param[out] err Details of an error that may have occurred
 void vim_set_current_buffer(Buffer buffer, Error *err)
-  FUNC_ATTR_DEFERRED
 {
   buf_T *buf = find_buffer_by_handle(buffer, err);
 
@@ -493,7 +482,6 @@ Window vim_get_current_window(void)
 ///
 /// @param handle The window handle
 void vim_set_current_window(Window window, Error *err)
-  FUNC_ATTR_DEFERRED
 {
   win_T *win = find_window_by_handle(window, err);
 
@@ -545,7 +533,6 @@ Tabpage vim_get_current_tabpage(void)
 /// @param handle The tab page handle
 /// @param[out] err Details of an error that may have occurred
 void vim_set_current_tabpage(Tabpage tabpage, Error *err)
-  FUNC_ATTR_DEFERRED
 {
   tabpage_T *tp = find_tab_by_handle(tabpage, err);
 
@@ -609,6 +596,7 @@ Dictionary vim_get_color_map(void)
 
 
 Array vim_get_api_info(uint64_t channel_id)
+  FUNC_ATTR_ASYNC
 {
   Array rv = ARRAY_DICT_INIT;
 

src/nvim/api/window.c

@@ -54,7 +54,6 @@ ArrayOf(Integer, 2) window_get_cursor(Window window, Error *err)
 /// @param pos the (row, col) tuple representing the new position
 /// @param[out] err Details of an error that may have occurred
 void window_set_cursor(Window window, ArrayOf(Integer, 2) pos, Error *err)
-  FUNC_ATTR_DEFERRED
 {
   win_T *win = find_window_by_handle(window, err);
 
@@ -118,7 +117,6 @@ Integer window_get_height(Window window, Error *err)
 /// @param height the new height in rows
 /// @param[out] err Details of an error that may have occurred
 void window_set_height(Window window, Integer height, Error *err)
-  FUNC_ATTR_DEFERRED
 {
   win_T *win = find_window_by_handle(window, err);
 
@@ -162,7 +160,6 @@ Integer window_get_width(Window window, Error *err)
 /// @param width the new width in columns
 /// @param[out] err Details of an error that may have occurred
 void window_set_width(Window window, Integer width, Error *err)
-  FUNC_ATTR_DEFERRED
 {
   win_T *win = find_window_by_handle(window, err);
 
@@ -208,7 +205,6 @@ Object window_get_var(Window window, String name, Error *err)
 /// @param[out] err Details of an error that may have occurred
 /// @return The old value
 Object window_set_var(Window window, String name, Object value, Error *err)
-  FUNC_ATTR_DEFERRED
 {
   win_T *win = find_window_by_handle(window, err);
 
@@ -244,7 +240,6 @@ Object window_get_option(Window window, String name, Error *err)
 /// @param value The option value
 /// @param[out] err Details of an error that may have occurred
 void window_set_option(Window window, String name, Object value, Error *err)
-  FUNC_ATTR_DEFERRED
 {
   win_T *win = find_window_by_handle(window, err);
 

src/nvim/func_attr.h

@@ -179,7 +179,7 @@
 #endif
 
 #ifdef DEFINE_FUNC_ATTRIBUTES
-  #define FUNC_ATTR_DEFERRED
+  #define FUNC_ATTR_ASYNC
   #define FUNC_ATTR_MALLOC REAL_FATTR_MALLOC
   #define FUNC_ATTR_ALLOC_SIZE(x) REAL_FATTR_ALLOC_SIZE(x)
   #define FUNC_ATTR_ALLOC_SIZE_PROD(x,y) REAL_FATTR_ALLOC_SIZE_PROD(x,y)

src/nvim/map.c

@@ -116,5 +116,5 @@ MAP_IMPL(cstr_t, uint64_t, DEFAULT_INITIALIZER)
 MAP_IMPL(cstr_t, ptr_t, DEFAULT_INITIALIZER)
 MAP_IMPL(ptr_t, ptr_t, DEFAULT_INITIALIZER)
 MAP_IMPL(uint64_t, ptr_t, DEFAULT_INITIALIZER)
-#define MSGPACK_HANDLER_INITIALIZER {.fn = NULL, .defer = false}
+#define MSGPACK_HANDLER_INITIALIZER {.fn = NULL, .async = false}
 MAP_IMPL(String, MsgpackRpcRequestHandler, MSGPACK_HANDLER_INITIALIZER)

src/nvim/msgpack_rpc/channel.c

@@ -450,16 +450,16 @@ static void handle_request(Channel *channel, msgpack_object *request)
                                           method->via.bin.size);
   } else {
     handler.fn = msgpack_rpc_handle_missing_method;
-    handler.defer = false;
+    handler.async = true;
   }
 
   Array args = ARRAY_DICT_INIT;
   if (!msgpack_rpc_to_array(msgpack_rpc_args(request), &args)) {
     handler.fn = msgpack_rpc_handle_invalid_arguments;
-    handler.defer = false;
+    handler.async = true;
   }
 
-  bool defer = (!kv_size(channel->call_stack) && handler.defer);
+  bool async = kv_size(channel->call_stack) || handler.async;
   RequestEvent *event_data = xmalloc(sizeof(RequestEvent));
   event_data->channel = channel;
   event_data->handler = handler;
@@ -469,7 +469,7 @@ static void handle_request(Channel *channel, msgpack_object *request)
   loop_push_event(&loop, (Event) {
     .handler = on_request_event,
     .data = event_data
-  }, defer);
+  }, !async);
 }
 
 static void on_request_event(Event event)

src/nvim/msgpack_rpc/defs.h

@@ -11,9 +11,8 @@ typedef struct {
                uint64_t request_id,
                Array args,
                Error *error);
-  bool defer;  // Should the call be deferred to the main loop? This should
-               // be true if the function mutates editor data structures such
-               // as buffers, windows, tabs, or if it executes vimscript code.
+  bool async;  // function is always safe to run immediately instead of being
+               // put in a request queue for handling when nvim waits for input.
 } MsgpackRpcRequestHandler;
 
 /// Initializes the msgpack-rpc method table

src/nvim/msgpack_rpc/remote_ui.c

@@ -28,7 +28,7 @@ void remote_ui_init(void)
   connected_uis = pmap_new(uint64_t)();
   // Add handler for "attach_ui"
   String method = cstr_as_string("ui_attach");
-  MsgpackRpcRequestHandler handler = {.fn = remote_ui_attach, .defer = false};
+  MsgpackRpcRequestHandler handler = {.fn = remote_ui_attach, .async = true};
   msgpack_rpc_add_method_handler(method, handler);
   method = cstr_as_string("ui_detach");
   handler.fn = remote_ui_detach;