Add TabClosed event

TabClosed is triggered when a tab page closes.

src/nvim/ex_docmd.c

@@ -5328,10 +5328,12 @@ void tabpage_close_other(tabpage_T *tp, int forceit)
   int done = 0;
   win_T       *wp;
   int h = tabline_height();
+  char_u prev_idx[NUMBUFLEN];
 
   /* Limit to 1000 windows, autocommands may add a window while we close
    * one.  OK, so I'm paranoid... */
   while (++done < 1000) {
+    sprintf((char *)prev_idx, "%i", tabpage_index(tp));
     wp = tp->tp_firstwin;
     ex_win_close(forceit, wp, tp);
 
@@ -5340,6 +5342,7 @@ void tabpage_close_other(tabpage_T *tp, int forceit)
     if (!valid_tabpage(tp) || tp->tp_firstwin == wp)
       break;
   }
+  apply_autocmds(EVENT_TABCLOSED, prev_idx, prev_idx, FALSE, curbuf);
 
   redraw_tabline = TRUE;
   if (h != tabline_height())

src/nvim/fileio.c

@@ -5245,6 +5245,7 @@ static struct event_name {
   {"StdinReadPre",    EVENT_STDINREADPRE},
   {"SwapExists",      EVENT_SWAPEXISTS},
   {"Syntax",          EVENT_SYNTAX},
+  {"TabClosed",       EVENT_TABCLOSED},
   {"TabEnter",        EVENT_TABENTER},
   {"TabLeave",        EVENT_TABLEAVE},
   {"TabNew",          EVENT_TABNEW},
@@ -6634,7 +6635,8 @@ apply_autocmds_group (
         || event == EVENT_QUICKFIXCMDPRE
         || event == EVENT_COLORSCHEME
         || event == EVENT_QUICKFIXCMDPOST
-        || event == EVENT_JOBACTIVITY)
+        || event == EVENT_JOBACTIVITY
+        || event == EVENT_TABCLOSED)
       fname = vim_strsave(fname);
     else
       fname = FullName_save(fname, FALSE);

src/nvim/fileio.h

@@ -93,6 +93,7 @@ typedef enum auto_event {
   EVENT_SPELLFILEMISSING,       /* spell file missing */
   EVENT_CURSORMOVED,            /* cursor was moved */
   EVENT_CURSORMOVEDI,           /* cursor was moved in Insert mode */
+  EVENT_TABCLOSED,               /* a tab has closed */
   EVENT_TABLEAVE,               /* before leaving a tab page */
   EVENT_TABENTER,               /* after entering a tab page */
   EVENT_TABNEW,                 /* when creating a new tab */

src/nvim/window.c

@@ -1791,6 +1791,9 @@ static int close_last_window_tabpage(win_T *win, int free_buf, tabpage_T *prev_c
   }
   /* Since goto_tabpage_tp above did not trigger *Enter autocommands, do
    * that now. */
+  char_u prev_idx[NUMBUFLEN];
+  sprintf((char *)prev_idx, "%i", tabpage_index(prev_curtab));
+  apply_autocmds(EVENT_TABCLOSED, prev_idx, prev_idx, FALSE, curbuf);
   apply_autocmds(EVENT_WINENTER, NULL, NULL, FALSE, curbuf);
   apply_autocmds(EVENT_TABENTER, NULL, NULL, FALSE, curbuf);
   if (old_curbuf != curbuf)