4 files changed, 64 insertions, 27 deletions

diff --git a/src/nvim/api/buffer.c b/src/nvim/api/buffer.c
index c9ada8dfc0..12c97cfffb 100644
--- a/src/nvim/api/buffer.c
+++ b/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);
@@ -108,7 +106,7 @@ ArrayOf(String) buffer_get_line_slice(Buffer buffer,
   Array rv = ARRAY_DICT_INIT;
   buf_T *buf = find_buffer_by_handle(buffer, err);
 
-  if (!buf) {
+  if (!buf || !inbounds(buf, start)) {
     return rv;
   }
 
@@ -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);
 
@@ -179,6 +176,11 @@ void buffer_set_line_slice(Buffer buffer,
     return;
   }
 
+  if (!inbounds(buf, start)) {
+    api_set_error(err, Validation, _("Index out of bounds"));
+    return;
+  }
+
   start = normalize_index(buf, start) + (include_start ? 0 : 1);
   include_end = include_end || (end >= buf->b_ml.ml_line_count);
   end = normalize_index(buf, end) + (include_end ? 1 : 0);
@@ -334,7 +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);
 
@@ -370,7 +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);
 
@@ -421,7 +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);
 
@@ -467,7 +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);
 }
@@ -550,3 +548,10 @@ static int64_t normalize_index(buf_T *buf, int64_t index)
   index = index > buf->b_ml.ml_line_count ? buf->b_ml.ml_line_count : index;
   return index;
 }
+
+// Returns true if the 0-indexed `index` is within the 1-indexed buffer bounds.
+static bool inbounds(buf_T *buf, int64_t index)
+{
+  linenr_T nlines = buf->b_ml.ml_line_count;
+  return index >= -nlines && index < nlines;
+}
diff --git a/src/nvim/api/tabpage.c b/src/nvim/api/tabpage.c
index 1c958118e1..126ee4072d 100644
--- a/src/nvim/api/tabpage.c
+++ b/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);
 
diff --git a/src/nvim/api/vim.c b/src/nvim/api/vim.c
index 22bdbc2ee5..b9900b5d5a 100644
--- a/src/nvim/api/vim.c
+++ b/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
@@ -164,6 +162,55 @@ Object vim_eval(String str, Error *err)
   return rv;
 }
 
+/// Call the given function with the given arguments stored in an array.
+///
+/// @param fname Function to call
+/// @param args Functions arguments packed in an Array
+/// @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)
+{
+  Object rv = OBJECT_INIT;
+  if (args.size > MAX_FUNC_ARGS) {
+    api_set_error(err, Validation,
+      _("Function called with too many arguments."));
+    return rv;
+  }
+
+  // Convert the arguments in args from Object to typval_T values
+  typval_T vim_args[MAX_FUNC_ARGS + 1];
+  size_t i = 0;  // also used for freeing the variables
+  for (; i < args.size; i++) {
+    if (!object_to_vim(args.items[i], &vim_args[i], err)) {
+      goto free_vim_args;
+    }
+  }
+
+  try_start();
+  // Call the function
+  typval_T rettv;
+  int dummy;
+  int r = call_func((char_u *) fname.data, (int) fname.size,
+                    &rettv, (int) args.size, vim_args,
+                    curwin->w_cursor.lnum, curwin->w_cursor.lnum, &dummy,
+                    true,
+                    NULL);
+  if (r == FAIL) {
+    api_set_error(err, Exception, _("Error calling function."));
+  }
+  if (!try_end(err)) {
+    rv = vim_to_object(&rettv);
+  }
+  clear_tv(&rettv);
+
+free_vim_args:
+  while (i > 0) {
+    clear_tv(&vim_args[--i]);
+  }
+
+  return rv;
+}
+
 /// Calculates the number of display cells `str` occupies, tab is counted as
 /// one cell.
 ///
@@ -262,7 +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);
 }
@@ -271,7 +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);
 }
@@ -293,7 +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);
 }
@@ -324,7 +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);
 }
@@ -333,7 +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);
 }
@@ -342,7 +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);
 }
@@ -352,7 +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});
@@ -392,7 +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);
 
@@ -443,7 +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);
 
@@ -495,7 +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);
 
@@ -559,6 +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;
 
diff --git a/src/nvim/api/window.c b/src/nvim/api/window.c
index 5034c26c83..aad616c7bf 100644
--- a/src/nvim/api/window.c
+++ b/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);