vim-patch:8.1.2046: SafeState may be triggered at the wrong moment

Problem:    SafeState may be triggered at the wrong moment.
Solution:   Move it up higher to after where messages are processed.  Add a
            SafeStateAgain event to tigger there.

69198cb8c0

SafeStateAgain is N/A.
Move SafeState functions to state.c.

Co-authored-by: Bram Moolenaar <Bram@vim.org>

runtime/doc/vim_diff.txt

@@ -619,6 +619,7 @@ Eval:
   *v:sizeofpointer*
 
 Events:
+  *SafeStateAgain*
   *SigUSR1* Use |Signal| to detect `SIGUSR1` signal instead.
 
 Highlight groups:

src/nvim/getchar.c

@@ -885,6 +885,7 @@ int ins_typebuf(char *str, int noremap, int offset, bool nottyped, bool silent)
   if (++typebuf.tb_change_cnt == 0) {
     typebuf.tb_change_cnt = 1;
   }
+  state_no_longer_safe();
 
   addlen = (int)strlen(str);
 
@@ -1625,6 +1626,12 @@ int vgetc(void)
   // Execute Lua on_key callbacks.
   nlua_execute_on_key(c);
 
+  // Need to process the character before we know it's safe to do something
+  // else.
+  if (c != K_IGNORE) {
+    state_no_longer_safe();
+  }
+
   return c;
 }
 

src/nvim/normal.c

@@ -482,40 +482,6 @@ bool check_text_or_curbuf_locked(oparg_T *oap)
   return true;
 }
 
-static bool was_safe = false;
-static int not_safe_now = 0;
-
-/// Trigger SafeState if currently in s safe state, that is "safe" is TRUE and
-/// there is no typeahead.
-void may_trigger_safestate(bool safe)
-{
-  bool is_safe = safe
-                 && stuff_empty()
-                 && typebuf.tb_len == 0
-                 && !global_busy;
-
-  if (is_safe) {
-    apply_autocmds(EVENT_SAFESTATE, NULL, NULL, false, curbuf);
-  }
-  was_safe = is_safe;
-}
-
-/// Entering a not-safe state.
-void enter_unsafe_state(void)
-{
-  not_safe_now++;
-}
-
-/// Leaving a not-safe state.  Trigger SafeState if we were in a safe state
-/// before first calling enter_not_safe_state().
-void leave_unsafe_state(void)
-{
-  not_safe_now--;
-  if (not_safe_now == 0 && was_safe) {
-    apply_autocmds(EVENT_SAFESTATE, NULL, NULL, false, curbuf);
-  }
-}
-
 /// Normal state entry point. This is called on:
 ///
 /// - Startup, In this case the function never returns.
@@ -1434,7 +1400,7 @@ static int normal_check(VimState *state)
   quit_more = false;
 
   // it's not safe unless normal_check_safe_state() is called
-  was_safe = false;
+  state_no_longer_safe();
 
   // If skip redraw is set (for ":" in wait_return()), don't redraw now.
   // If there is nothing in the stuff_buffer or do_redraw is true,

src/nvim/state.c

@@ -268,3 +268,30 @@ void may_trigger_modechanged(void)
 
   restore_v_event(v_event, &save_v_event);
 }
+
+/// When true in a safe state when starting to wait for a character.
+static bool was_safe = false;
+
+/// Trigger SafeState if currently in s safe state, that is "safe" is TRUE and
+/// there is no typeahead.
+void may_trigger_safestate(bool safe)
+{
+  bool is_safe = safe
+                 && stuff_empty()
+                 && typebuf.tb_len == 0
+                 && !using_script()
+                 && !global_busy;
+
+  if (is_safe) {
+    apply_autocmds(EVENT_SAFESTATE, NULL, NULL, false, curbuf);
+  }
+  was_safe = is_safe;
+}
+
+/// Something changed which causes the state possibly to be unsafe, e.g. a
+/// character was typed.  It will remain unsafe until the next call to
+/// may_trigger_safestate().
+void state_no_longer_safe(void)
+{
+  was_safe = false;
+}