Subject: bug#71960: [PATCH] Improve `tab-line-tabs-fixed-window-buffers` sorting performance

From: Eval Exec <[email-masked]>
Date: Fri, 5 Jul 2024 20:39:39 +0800

Enhanced
`tab-line-tabs-fixed-window-buffers` performance by optimizing buffer
sorting mechanism. Replaced inefficient `seq-position` calls with a hash
table to cache buffer positions, significantly improving speed when
handling large buffer lists.

In GNU Emacs 31.0.50 (build 1, x86_64-pc-linux-gnu, GTK+ Version
3.24.42, cairo version 1.18.0)
Repository revision: 8198a144376cfea3490ea5628392fb3a49fec2d6
Repository branch: master
Windowing system distributor 'The X.Org Foundation', version 11.0.12401000
System Description: NixOS 24.05 (Uakari)

Configured using:
 'configure
 --prefix=/nix/store/l5b0bbsxvyxd2ggi6j86inz2fwl9prkp-emacs-git-20240628.0
 --disable-build-details --with-modules --with-x-toolkit=gtk3
 --with-cairo --with-xft --with-compress-install
 --with-toolkit-scroll-bars --with-native-compilation
 --without-imagemagick --with-mailutils --without-small-ja-dic
 --with-tree-sitter --with-xinput2 --with-xwidgets --with-dbus
 --with-selinux'
From fa047a52c0d40aace236bd56f1d8ca70935f438a Mon Sep 17 00:00:00 2001
From: Eval EXEC <[email-masked]>
Date: Fri, 5 Jul 2024 18:53:36 +0800
Subject: [PATCH] Improve `tab-line-tabs-fixed-window-buffers` sorting
 performance

* lsp/tab-line.el (tab-line-tabs-fixed-window-buffers): Enhanced
`tab-line-tabs-fixed-window-buffers` performance by optimizing buffer
sorting mechanism. Replaced inefficient `seq-position` calls with a hash
table to cache buffer positions, significantly improving speed when
handling large buffer lists.
---
 lisp/tab-line.el | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/lisp/tab-line.el b/lisp/tab-line.el
index 1d14fda9825..e4908c61542 100644
--- a/lisp/tab-line.el
+++ b/lisp/tab-line.el
@@ -555,10 +555,14 @@ This means that switching to a buffer previously shown in the same
 window will keep the same order of tabs that was before switching.
 And newly displayed buffers are added to the end of the tab line."
   (let* ((old-buffers (window-parameter nil 'tab-line-buffers))
+         (buffer-positions (let ((index-table (make-hash-table :test 'eq)))
+                             (seq-do-indexed
+                              (lambda (buf idx) (puthash buf idx index-table))
+                              old-buffers)
+                             index-table))
          (new-buffers (sort (tab-line-tabs-window-buffers)
                             :key (lambda (buffer)
-                                   (or (seq-position old-buffers buffer)
-                                       most-positive-fixnum)))))
+                                   (gethash buffer buffer-positions most-positive-fixnum)))))
     (set-window-parameter nil 'tab-line-buffers new-buffers)
     new-buffers))
 
-- 
2.44.1