Implement handling of terminal focus events

Two new keys have been added to key_name_entry in keymap.c:
`FocusGained` and `FocusLost`.

Two cases have been added to the key handing switch in edit.c each
applying their respective autocmds.

In normal.c two functions have been added alongside nv_cursorhold doing
a similar job of applying the autocmd for the appropriate key.

tui/input.c has a new function `handle_focus_event` which eats either of
the control sequences for focus gained or lost. This function is checked
before handle_bracketed_paste and handle_forced_escape.

tui.c registers neovim as able to receive these control sequences in
terminfo_start and undoes that in terminfo_stop.

Closes #2302

1 files changed, 14 insertions, 0 deletions

diff --git a/src/nvim/normal.c b/src/nvim/normal.c
index d6bc416c91..78df4ea7ea 100644
--- a/src/nvim/normal.c
+++ b/src/nvim/normal.c
@@ -349,6 +349,8 @@ static const struct nv_cmd {
   {K_F8,      farsi_fkey,     0,                      0},
   {K_F9,      farsi_fkey,     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[]. */
@@ -7715,6 +7717,18 @@ static void nv_event(cmdarg_T *cap)
   cap->retval |= CA_COMMAND_BUSY;       // don't call edit() now
 }
 
+/// 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".
  */