perf(tabs): rate limit centaur-tabs-buffer-update-groups

`centaur-tabs-buffer-update-groups` walks every buffer to determine the
group it belongs to. This function can be called execessively (upwards
of 1,000 times per second in certain conditions), as it is called on
every redisplay (it is indirectly attached to `tab-line-format`). This
rate limits its calls to about 10 per second.

Close: doomemacs#7792
Ref: ema2159/centaur-tabs#222

modules/ui/tabs/config.el

@@ -1,5 +1,14 @@
 ;;; ui/tabs/config.el -*- lexical-binding: t; -*-
 
+(defcustom +tabs-buffer-update-groups-delay 0.1
+  "Minimum wait time (in seconds) before tab groups are recalculated."
+  :type 'float
+  :group 'doom)
+
+
+;;
+;;; Packages
+
 (use-package! centaur-tabs
   :hook (doom-first-file . centaur-tabs-mode)
   :init
@@ -20,7 +29,20 @@
     (defun +tabs-disable-centaur-tabs-mode-maybe-h ()
       "Disable `centaur-tabs-mode' in current buffer."
       (when (centaur-tabs-mode-on-p)
-        (centaur-tabs-local-mode)))))
+        (centaur-tabs-local-mode))))
+
+  ;; HACK: `centaur-tabs-buffer-update-groups' is both expensive and called too
+  ;;   frequently. There really is no reason to call it more than 10 times per
+  ;;   second, as buffers rarely change groups more frequently than that.
+  (let ((time (float-time)))
+    (defadvice! +tabs--rate-limit-buffer-update-groups-a (fn)
+      :around #'centaur-tabs-buffer-update-groups
+      (let ((now (float-time)))
+        (if-let ((buf (and (< now (+ time +tabs-buffer-update-groups-delay))
+                           (assq (current-buffer) centaur-tabs--buffers))))
+            (car (nth 2 buf))
+          (setq time now)
+          (funcall fn))))))
 
 
 ;; TODO tab-bar-mode (emacs 27)