From 91189839ab886c5bae07c7deab6a2384f5a37771 Mon Sep 17 00:00:00 2001
From: JSDurand <mmemmew@gmail.com>
Date: Fri, 18 Nov 2022 13:53:16 +0800
Subject: basic: clear invisible buffers

One day I found that my Emacs had accumulated a bunch of invisible
buffers.  So I want to make sure I have a convenient way to clean up
invisible buffers easily, once the need arises.

* basic.el (durand-invisible-buffer-unsafe-regex): A regular
  expression that matches some buffers that are not to be killed
  automatically.

(durand-clear-invisible-buffers): Kill invisible buffers that are not
important.

(global-map): Bind the function to "C-c k".
---
 basic.el | 37 +++++++++++++++++++++++++++++++++++++
 1 file changed, 37 insertions(+)

diff --git a/basic.el b/basic.el
index aa087f1..60d8dd2 100644
--- a/basic.el
+++ b/basic.el
@@ -199,6 +199,8 @@ This will maintain the frame's width and height as well."
 
 ;;; display-buffer-alist
 
+(require 'rx)
+
 (setq display-buffer-alist
       `((,(rx (seq bos "*Help*" eos))
          (display-buffer-in-side-window)
@@ -564,6 +566,41 @@ left.  --- 2022-11-17 22:56:20.746698"
 (advice-add #'read-buffer-to-switch :override
             #'durand-read-buffer-to-switch)
 
+;;; Clear invisible buffers
+
+(defvar durand-invisible-buffer-unsafe-regex
+  (rx-to-string '(or
+                  "Minibuf"
+                  "Echo Area"
+                  "code-conversion-work"
+                  "code-converting-work"
+                  "address")
+                t)
+  "I do not want to kill some invisible buffers.
+This variable is a regular expression that should match those
+buffers that I do not want to kill automatically.")
+
+(defun durand-clear-invisible-buffers ()
+  "Kill invisible buffers that are not known to be safe to kill."
+  (interactive)
+  (let ((count 0))
+    (mapc
+     (lambda (buffer)
+       (let ((name (buffer-name buffer))
+             (inhibit-changing-match-data t))
+         (cond
+          ;; ignore non-invisible buffers
+          ((or (= (length name) 0) (not (= (aref name 0) 32))))
+          ;; ignore some "potentially unsafe" buffers
+          ((string-match durand-invisible-buffer-unsafe-regex name))
+          ;; ignore buffers that are associated with live processes
+          ((get-buffer-process buffer))
+          ((setq count (1+ count)) (kill-buffer buffer)))))
+     (buffer-list))
+    (message "Cleared %d invisible buffers" count)))
+
+(define-key global-map (vector 3 ?k) #'durand-clear-invisible-buffers)
+
 ;;; Save close
 
 ;;;###autoload
-- 
cgit v1.2.3-18-g5258