记录第一次给 GNU/Emacs 上游贡献代码的经历

execvy@gmail.com (EXEC) — Thu, 04 Jul 2024 12:12:40 +0800

Recently, I noticed that when I open a large number of buffers in Emacs (for example, all 1000+ files in a Rust project), switching between tabs using tab-line becomes noticeably sluggish. I suspected a performance issue somewhere.

After conducting a thorough investigation using (profiler-start) and (profiler-report), I obtained the following CPU usage statistics:

3344  84% - redisplay_internal (C function)
2665  67%  - eval
2608  66%   - tab-line-format
2607  66%    - tab-line-tabs-fixed-window-buffers
2520  63%     - #<byte-code-function 337>
2507  63%      - seq-position
2489  63%       - seq-do
2485  63%        - mapc
2130  54%         - #<byte-code-function 3A4>
 623  15%            equal
   2   0%            throw
  12   0%         make-closure
  84   2%     + tab-line-tabs-window-buffers
   1   0%    + tab-line-cache-key-default
  48   1%   + mode--line-format-right-align
   5   0%   + breadcrumb--header-line
   2   0%   + if
   1   0%     unless

Upon identifying the corresponding code, it became clear that the performance bottleneck was within the tab-line-tabs-fixed-window-buffers function:

Enhance Emacs rg.el with which-function support

execvy@gmail.com (EXEC) — Thu, 02 May 2024 11:33:13 +0800

I frequently use rg.el in my daily work. While rg only displays the content of
the target lines, I want Emacs’ rg.el to tell me what the which-function is
for the target content after searching. Therefore, I modified which-function
and made some hacks to rg.el.

The effect is as follows:

The Source code:

  (defun shorten-string (str)
	(if (> (length str) 30)
		(concat (substring str 0 15) "…" (substring str -14))
	  str))

  (defun exec/rg-hack ()
	(interactive)
	(let* ((msg (get-text-property (point) 'compilation-message)))
	  (if msg
		  (let* ((loc (compilation--message->loc msg))
                 (file (caar (compilation--loc->file-struct loc)))
                 (line (compilation--loc->line loc))
                 (col (compilation--loc->col loc))
                 (function_name
				  (exec/lsp-which-function file line col))
                 (text
				  (format "%-30s │"
						  (shorten-string (or function_name ""))))
                 (ov
				  (make-overlay (line-beginning-position)
								(1+ (line-beginning-position))
								nil
								t)))

			(overlay-put
             ov 'before-string
             (propertize text 'face 'font-lock-property-name-face))
			(overlay-put ov 'evaporate t)))))

  (defun exec/rg-hint-all (&rest args)
	(interactive)
	(sit-for 0.01)
	(with-current-buffer (rg-buffer-name)
	  (defvar-local rg-hack-lines 1)
	  (while (and (not (eobp)) (< rg-hack-lines 300))
		(exec/rg-hack)
		(forward-line)
		(setq-local rg-hack-lines (1+ rg-hack-lines))
		(if (= (% rg-hack-lines 10) 0)
			(sit-for 0.01)))
	  (goto-char (point-min)))

	(unless exec/which-function-current-buffer-already-exist
	  (if exec/which-function-last-buffer-name
		  (kill-buffer (find-file-noselect exec/which-function-last-buffer-name))
		)
	  )
	(setq-local exec/which-function-current-buffer-already-exist nil)
	(setq-local exec/which-function-last-buffer-name "")
	)


  (defvar-local exec/which-function-last-buffer-name "")
  (defvar-local exec/which-function-current-buffer-already-exist nil)
  (defun exec/lsp-which-function (file line column)
	(unless (eq file exec/which-function-last-buffer-name)
	  (unless exec/which-function-current-buffer-already-exist
		(if exec/which-function-last-buffer-name
			(kill-buffer (find-file-noselect exec/which-function-last-buffer-name))
		  )
		)
	  (setq-local exec/which-function-current-buffer-already-exist (get-file-buffer file))
	  (setq-local exec/which-function-last-buffer-name file))
	(let ((buffer (find-file-noselect file)))
	  (with-current-buffer buffer
		(goto-line line)
		(move-to-column column)
		(which-function))))

  (defun exec/setup-rg-hint (&rest args)
	(add-to-list 'compilation-finish-functions 'exec/rg-hint-all))


  (add-hook 'rg-mode-hook 'exec/setup-rg-hint))

Emacs on Eval-EXEC

记录第一次给 GNU/Emacs 上游贡献代码的经历

Enhance Emacs rg.el with which-function support