ui: Replace cursor_{on,off} by busy_{stop,start}

Switching cursor off is only necessary in two occasions:

- When redrawing to avoid terminal flickering
- When the editor is busy

The first can now be handled by the TUI, so most calls to ui_cursor_off can be
removed from the core.

So, before this commit it was only necessary to switch the cursor off to notify
the user that nvim was running some long operation. Now the cursor_{on,off}
functions have been replaced by busy_{stop,start} which can be handled in a
UI-specific way(turning the cursor off or showing a busy indicator, for
example).

To make things even more simpler, nvim is always busy except when waiting for
user input or other asynchronous events: It automatically switches to a non-busy
state when the event loop is about to be entered for more than 100 milliseconds.

`ui_busy_start` can be called when its not desired to change the busy state in
the event loop (As its now done by functions that perform blocking shell
invocations).

1 files changed, 14 insertions, 6 deletions

diff --git a/src/nvim/tui/tui.c b/src/nvim/tui/tui.c
index b95a22d48b..610419d12c 100644
--- a/src/nvim/tui/tui.c
+++ b/src/nvim/tui/tui.c
@@ -45,6 +45,7 @@ typedef struct {
   int out_fd;
   int old_height;
   bool can_use_terminal_scroll;
+  bool busy;
   HlAttrs attrs, print_attrs;
   Cell **screen;
   struct {
@@ -80,6 +81,7 @@ typedef struct {
 void tui_start(void)
 {
   TUIData *data = xcalloc(1, sizeof(TUIData));
+  data->busy = true;
   UI *ui = xcalloc(1, sizeof(UI));
   ui->data = data;
   data->attrs = data->print_attrs = EMPTY_ATTRS;
@@ -134,8 +136,8 @@ void tui_start(void)
   ui->clear = tui_clear;
   ui->eol_clear = tui_eol_clear;
   ui->cursor_goto = tui_cursor_goto;
-  ui->cursor_on = tui_cursor_on;
-  ui->cursor_off = tui_cursor_off;
+  ui->busy_start = tui_busy_start;
+  ui->busy_stop = tui_busy_stop;
   ui->mouse_on = tui_mouse_on;
   ui->mouse_off = tui_mouse_off;
   ui->insert_mode = tui_insert_mode;
@@ -342,14 +344,14 @@ static void tui_cursor_goto(UI *ui, int row, int col)
   unibi_goto(ui, row, col);
 }
 
-static void tui_cursor_on(UI *ui)
+static void tui_busy_start(UI *ui)
 {
-  unibi_out(ui, unibi_cursor_normal);
+  ((TUIData *)ui->data)->busy = true;
 }
 
-static void tui_cursor_off(UI *ui)
+static void tui_busy_stop(UI *ui)
 {
-  unibi_out(ui, unibi_cursor_invisible);
+  ((TUIData *)ui->data)->busy = false;
 }
 
 static void tui_mouse_on(UI *ui)
@@ -527,7 +529,13 @@ static void tui_flush(UI *ui)
   }
 
   unibi_goto(ui, data->row, data->col);
+
+  if (!data->busy) {
+    unibi_out(ui, unibi_cursor_normal);
+  }
+
   flush_buf(ui);
+  unibi_out(ui, unibi_cursor_invisible);
 }
 
 static void tui_suspend(UI *ui)