eventloop: FocusGained: schedule event instead of pseudokey

closes #4840
closes #6164

src/nvim/aucmd.c

@@ -0,0 +1,48 @@
+// This is an open source non-commercial project. Dear PVS-Studio, please check
+// it. PVS-Studio Static Code Analyzer for C, C++ and C#: http://www.viva64.com
+
+#include "nvim/os/os.h"
+#include "nvim/fileio.h"
+#include "nvim/vim.h"
+#include "nvim/main.h"
+#include "nvim/screen.h"
+#include "nvim/ui.h"
+
+#ifdef INCLUDE_GENERATED_DECLARATIONS
+# include "aucmd.c.generated.h"
+#endif
+
+static void focusgained_event(void **argv)
+{
+  bool *gained = argv[0];
+  do_autocmd_focusgained(*gained);
+  xfree(gained);
+}
+void aucmd_schedule_focusgained(bool gained)
+{
+  bool *gainedp = xmalloc(sizeof(*gainedp));
+  *gainedp = gained;
+  loop_schedule(&main_loop, event_create(focusgained_event, 1, gainedp));
+}
+
+static void do_autocmd_focusgained(bool gained)
+  FUNC_ATTR_NONNULL_ALL
+{
+  static bool recursive = false;
+
+  if (recursive) {
+    return;  // disallow recursion
+  }
+  recursive = true;
+  bool has_any = has_event(EVENT_FOCUSGAINED) || has_event(EVENT_FOCUSLOST);
+  bool did_any = apply_autocmds((gained ? EVENT_FOCUSGAINED : EVENT_FOCUSLOST),
+                                NULL, NULL, false, curbuf);
+  if (has_any && !did_any) {
+    // HACK: Reschedule, hoping that the next event-loop tick will pick this up
+    // during a "regular" state (as opposed to a weird implicit state, e.g.
+    // early_init()..win_alloc_first() which disables autocommands).
+    aucmd_schedule_focusgained(gained);
+  }
+  recursive = false;
+}
+

src/nvim/aucmd.h

@@ -0,0 +1,9 @@
+#ifndef NVIM_AUCMD_H
+#define NVIM_AUCMD_H
+
+#ifdef INCLUDE_GENERATED_DECLARATIONS
+# include "aucmd.h.generated.h"
+#endif
+
+#endif  // NVIM_AUCMD_H
+

src/nvim/edit.c

@@ -974,14 +974,6 @@ static int insert_handle_key(InsertState *s)
     multiqueue_process_events(main_loop.events);
     break;
 
-  case K_FOCUSGAINED:  // Neovim has been given focus
-    apply_autocmds(EVENT_FOCUSGAINED, NULL, NULL, false, curbuf);
-    break;
-
-  case K_FOCUSLOST:   // Neovim has lost focus
-    apply_autocmds(EVENT_FOCUSLOST, NULL, NULL, false, curbuf);
-    break;
-
   case K_HOME:        // <Home>
   case K_KHOME:
   case K_S_HOME:
@@ -3167,8 +3159,7 @@ static bool ins_compl_prep(int c)
 
   /* Ignore end of Select mode mapping and mouse scroll buttons. */
   if (c == K_SELECT || c == K_MOUSEDOWN || c == K_MOUSEUP
-      || c == K_MOUSELEFT || c == K_MOUSERIGHT || c == K_EVENT
-      || c == K_FOCUSGAINED || c == K_FOCUSLOST) {
+      || c == K_MOUSELEFT || c == K_MOUSERIGHT || c == K_EVENT) {
     return retval;
   }
 

src/nvim/ex_getln.c

@@ -1620,14 +1620,6 @@ static int command_line_handle_key(CommandLineState *s)
     }
     return command_line_not_changed(s);
 
-  case K_FOCUSGAINED:  // Neovim has been given focus
-    apply_autocmds(EVENT_FOCUSGAINED, NULL, NULL, false, curbuf);
-    return command_line_not_changed(s);
-
-  case K_FOCUSLOST:   // Neovim has lost focus
-    apply_autocmds(EVENT_FOCUSLOST, NULL, NULL, false, curbuf);
-    return command_line_not_changed(s);
-
   default:
     // Normal character with no special meaning.  Just set mod_mask
     // to 0x0 so that typing Shift-Space in the GUI doesn't enter

src/nvim/keymap.c

@@ -286,8 +286,6 @@ static struct key_name_entry {
   {K_SNR,             (char_u *)"SNR"},
   {K_PLUG,            (char_u *)"Plug"},
   {K_PASTE,           (char_u *)"Paste"},
-  {K_FOCUSGAINED,     (char_u *)"FocusGained"},
-  {K_FOCUSLOST,       (char_u *)"FocusLost"},
   {0,                 NULL}
 };
 

src/nvim/keymap.h

@@ -428,8 +428,6 @@ enum key_extra {
 #define K_CMDWIN        TERMCAP2KEY(KS_EXTRA, KE_CMDWIN)
 
 #define K_DROP          TERMCAP2KEY(KS_EXTRA, KE_DROP)
-#define K_FOCUSGAINED   TERMCAP2KEY(KS_EXTRA, KE_FOCUSGAINED)
-#define K_FOCUSLOST     TERMCAP2KEY(KS_EXTRA, KE_FOCUSLOST)
 
 #define K_EVENT         TERMCAP2KEY(KS_EXTRA, KE_EVENT)
 #define K_PASTE         TERMCAP2KEY(KS_EXTRA, KE_PASTE)

src/nvim/normal.c

@@ -345,8 +345,6 @@ static const struct nv_cmd {
   { K_F8,      farsi_f8,       0,                      0 },
   { K_F9,      farsi_f9,       0,                      0 },
   { K_EVENT,   nv_event,       NV_KEEPREG,             0 },
-  { K_FOCUSGAINED, nv_focusgained, NV_KEEPREG,         0 },
-  { K_FOCUSLOST,   nv_focuslost,   NV_KEEPREG,         0 },
 };
 
 /* Number of commands in nv_cmds[]. */
@@ -7961,18 +7959,6 @@ static void nv_event(cmdarg_T *cap)
   finish_op = false;
 }
 
-/// Trigger FocusGained event.
-static void nv_focusgained(cmdarg_T *cap)
-{
-  apply_autocmds(EVENT_FOCUSGAINED, NULL, NULL, false, curbuf);
-}
-
-/// Trigger FocusLost event.
-static void nv_focuslost(cmdarg_T *cap)
-{
-  apply_autocmds(EVENT_FOCUSLOST, NULL, NULL, false, curbuf);
-}
-
 /*
  * Return TRUE when 'mousemodel' is set to "popup" or "popup_setpos".
  */

src/nvim/state.c

@@ -26,10 +26,11 @@ void state_enter(VimState *s)
     int check_result = s->check ? s->check(s) : 1;
 
     if (!check_result) {
-      break;
+      break;     // Terminate this state.
     } else if (check_result == -1) {
-      continue;
+      continue;  // check() again.
     }
+    // Execute this state.
 
     int key;
 

src/nvim/terminal.c

@@ -432,14 +432,6 @@ static int terminal_execute(VimState *state, int key)
   TerminalState *s = (TerminalState *)state;
 
   switch (key) {
-    case K_FOCUSGAINED:  // nvim has been given focus
-      apply_autocmds(EVENT_FOCUSGAINED, NULL, NULL, false, curbuf);
-      break;
-
-    case K_FOCUSLOST:   // nvim has lost focus
-      apply_autocmds(EVENT_FOCUSLOST, NULL, NULL, false, curbuf);
-      break;
-
     // Temporary fix until paste events gets implemented
     case K_PASTE:
       break;

src/nvim/tui/input.c

@@ -8,6 +8,7 @@
 #include "nvim/api/private/helpers.h"
 #include "nvim/ascii.h"
 #include "nvim/main.h"
+#include "nvim/aucmd.h"
 #include "nvim/os/os.h"
 #include "nvim/os/input.h"
 #include "nvim/event/rstream.h"
@@ -280,9 +281,9 @@ static void timer_cb(TimeWatcher *watcher, void *data)
 
 /// Handle focus events.
 ///
-/// If the upcoming sequence of bytes in the input stream matches either the
-/// escape code for focus gained `<ESC>[I` or focus lost `<ESC>[O` then consume
-/// that sequence and push the appropriate event into the input queue
+/// If the upcoming sequence of bytes in the input stream matches the termcode
+/// for "focus gained" or "focus lost", consume that sequence and schedule an
+/// event on the main loop.
 ///
 /// @param input the input stream
 /// @return true iff handle_focus_event consumed some input
@@ -294,11 +295,7 @@ static bool handle_focus_event(TermInput *input)
     // Advance past the sequence
     bool focus_gained = *rbuffer_get(input->read_stream.buffer, 2) == 'I';
     rbuffer_consumed(input->read_stream.buffer, 3);
-    if (focus_gained) {
-      enqueue_input(input, FOCUSGAINED_KEY, sizeof(FOCUSGAINED_KEY) - 1);
-    } else {
-      enqueue_input(input, FOCUSLOST_KEY, sizeof(FOCUSLOST_KEY) - 1);
-    }
+    aucmd_schedule_focusgained(focus_gained);
     return true;
   }
   return false;