ui: Refactor so that busy state won't be the default

Even though assuming nvim is busy most times is simpler, it has a problem: A lot
of unnecessary busy_start/busy_stop notifications are sent to the UI. That's
because in the majority of scenarios almost no time is spent between
`event_poll` calls.

This restores the normal behavior which is to call busy_start only when nvim is
going to perform some task that can take a significant amount of time. Also
improve the usage of buffering in the TUI when changing the cursor state.

1 files changed, 1 insertions, 4 deletions

diff --git a/src/nvim/ui.c b/src/nvim/ui.c
index 2189021d22..443b50da87 100644
--- a/src/nvim/ui.c
+++ b/src/nvim/ui.c
@@ -45,7 +45,7 @@ static struct {
 } sr;
 static int current_attr_code = 0;
 static bool pending_cursor_update = false;
-static int busy = 1;
+static int busy = 0;
 static int height, width;
 
 // This set of macros allow us to use UI_CALL to invoke any function on
@@ -155,7 +155,6 @@ void ui_busy_start(void)
 {
   if (!(busy++)) {
     UI_CALL(busy_start);
-    ui_flush();
   }
 }
 
@@ -163,11 +162,9 @@ void ui_busy_stop(void)
 {
   if (!(--busy)) {
     UI_CALL(busy_stop);
-    ui_flush();
   }
 }
 
-
 void ui_mouse_on(void)
 {
   UI_CALL(mouse_on);