mu4e: clean up temp file handling

Use a temp file directory per mu4e session

Remove files when a buffer is closed, not after 30 secs

mu4e/mu4e-helpers.el

@@ -534,11 +534,16 @@ string after PROMPT."
   (let ((timestr (read-string (mu4e-format "%s" prompt))))
     (apply 'encode-time (parse-time-string timestr))))
 
+
+(defvar mu4e--temp-dir nil "Directory for temporary files.
+Created when mu4e starts, and removed when it closes.")
+
 (defun mu4e-make-temp-file (ext)
   "Create a self-destructing temporary file with extension EXT.
 The file will self-destruct in a short while, enough to open it
 in an external program."
-  (let ((tmpfile (make-temp-file "mu4e-" nil (concat "." ext))))
+  (let* ((temporary-file-directory (or mu4e--temp-dir temporary-file-directory))
+         (tmpfile (make-temp-file "mu4e-" nil (concat "." ext))))
     (run-at-time "30 sec" nil
                  (lambda () (ignore-errors (delete-file tmpfile))))
     tmpfile))

mu4e/mu4e-mime-parts.el

@@ -1,6 +1,6 @@
 ;;; mu4e-mime-parts.el --- Dealing with MIME-parts & URLs -*- lexical-binding: t -*-
 
-;; Copyright (C) 2023-2024 Dirk-Jan C. Binnema
+;; Copyright (C) 2023-2026 Dirk-Jan C. Binnema
 
 ;; Author: Dirk-Jan C. Binnema <djcb@djcbsoftware.nl>
 ;; Maintainer: Dirk-Jan C. Binnema <djcb@djcbsoftware.nl>
@@ -63,25 +63,25 @@ See `mu4e--uniquify-file-name' for an example."
 
 ;; remember the mime-handles, so we can clean them up when
 ;; we quit this buffer.
-(defvar-local mu4e--view-gnus-article-mime-handles nil)
+
+(defvar-local mu4e--view-gnus-article-mime-handles nil
+  "MIME handles for the message in this buffer.")
 (put 'mu4e--view-gnus-article-mime-handles 'permanent-local t)
 
-(defun mu4e--view-kill-mime-handles ()
-  "Kill cached MIME-handles, if any."
+(defvar-local mu4e--view-temp-files nil
+  "Temporary files.")
+(put 'mu4e--view-temp-files 'permanent-local t)
+
+(defun mu4e--view-buffer-cleanup ()
+  "Clean-up some internals when killing the view buffer."
+  ;; Kill cached MIME-handles, if any.
   (when mu4e--view-gnus-article-mime-handles
     (mm-destroy-parts mu4e--view-gnus-article-mime-handles)
-    (setq mu4e--view-gnus-article-mime-handles nil)))
-
-;; Temp directories created to hand attachments to external openers; cleaned up
-;; when the view buffer is killed.
-(defvar-local mu4e--view-temp-dirs nil)
-(put 'mu4e--view-temp-dirs 'permanent-local t)
-
-(defun mu4e--view-kill-temp-dirs ()
-  "Delete temp dirs created for opening MIME-parts externally."
-  (dolist (dir mu4e--view-temp-dirs)
-    (ignore-errors (delete-directory dir)))
-  (setq mu4e--view-temp-dirs nil))
+    (setq mu4e--view-gnus-article-mime-handles nil))
+  ;; Delete temp files created for opening MIME-parts externally.
+  (dolist (file mu4e--view-temp-files)
+    (ignore-errors (delete-file file)))
+  (setq mu4e--view-temp-files nil))
 
 ;;; MIME-parts
 (defvar-local mu4e--view-mime-parts nil
@@ -438,23 +438,25 @@ Each of the actions is a plist with keys
 
 (defun mu4e--view-mime-part-to-temp-file (handle)
   "Write MIME-part HANDLE to a temporary file and return the file name.
+
 The filename is deduced from the MIME-part's filename, or
 otherwise random; the result is placed in a temporary directory
 with a unique name. Returns the full path for the file created.
-The directory is registered for cleanup when the current view
-buffer is killed (see `mu4e--view-kill-temp-dirs')."
-  (let* ((tmpdir (make-temp-file "mu4e-temp-" t))
-         (fname (mm-handle-filename handle))
+
+The file is registered for cleanup when the current view
+buffer is killed."
+  (let* ((fname (mm-handle-filename handle))
          (fname (and fname
                      (gnus-map-function mm-file-name-rewrite-functions
                                         (file-name-nondirectory fname))))
          (fname (if fname
                     (mu4e-join-paths
-                     tmpdir (replace-regexp-in-string "/" "-" fname))
-                  (let ((temporary-file-directory tmpdir))
-                    (make-temp-file "mimepart")))))
+                     mu4e--temp-dir
+                     (replace-regexp-in-string "/" "-" fname))
+                  (let ((temporary-file-directory mu4e--temp-dir))
+                    (make-temp-file "mime-part-")))))
     (mm-save-part-to-file handle fname)
-    (push tmpdir mu4e--view-temp-dirs)
+    (push fname mu4e--view-temp-files)
     fname))
 
 (defun mu4e--view-open-file (file &optional force-ask)

mu4e/mu4e-view.el

@@ -654,8 +654,7 @@ activates URLs (in plain-text mode only)."
           (setq mu4e--view-gnus-article-mime-handles gnus-article-mime-handles
                 gnus-article-decoded-p gnus-article-decode-hook)
           (set-buffer-modified-p nil)
-          (add-hook 'kill-buffer-hook #'mu4e--view-kill-mime-handles)
-          (add-hook 'kill-buffer-hook #'mu4e--view-kill-temp-dirs))
+          (add-hook 'kill-buffer-hook #'mu4e--view-buffer-cleanup))
       (epg-error
        (mu4e-message "EPG error: %s; fall back to raw view"
                      (error-message-string err))))))

mu4e/mu4e.el

@@ -158,6 +158,9 @@ mu4e is already running, invoke FUNC (if non-nil).
 
 Otherwise, check requirements, then start mu4e. When successful,
 invoke FUNC (if available) afterwards."
+  ;; create dir for temporary files.
+  (unless (and mu4e--temp-dir (file-directory-p mu4e--temp-dir))
+    (setq mu4e--temp-dir (make-temp-file "mu4e-" t)))
   (unless (mu4e-context-current)
     (mu4e--context-autoswitch nil mu4e-context-policy))
   (setq mu4e-pong-func
@@ -216,7 +219,10 @@ invoke FUNC (if available) afterwards."
          (when (member major-mode
                        '(mu4e-headers-mode mu4e-view-mode mu4e-main-mode))
            (kill-buffer)))))
-   (buffer-list)))
+   (buffer-list))
+  (when mu4e--temp-dir
+    (ignore-errors (delete-directory mu4e--temp-dir 'recursive))
+    (setq mu4e--temp-dir nil)))
 
 ;;; Handlers
 (defun mu4e--default-handler (&rest args)