better handle maildir cache

- get an updated maildir list after indexing
- add mu4e-added items to the list opportunistically

Remove mu4e-clear-caches / mu4e-cache-maildir-list to mu4e-obsolete.el

Fixes #2537.

NEWS.org

@@ -81,8 +81,10 @@
       If and how much this helps, depends on your setup, see the
  =mu4e-mu-allow-temp-file= docstring for details on how to determine this.
 
-    - Jumping to the 'jo' /other/ Maildirs used to quite slow the first time, but
-      this now done on the server side, making it much faster.
+    - Maildir lists are now generated server-side; so e.g. jumping to the 'jo'
+ /other/ Maildirs used to be quite slow the first time.
+
+ ~mu4e-cache-maildir-list~ is obsolete / non-functional now.
 
     - after retrieving mail (~mu4e-update-mail-and-index~), save the output of the
       retrieval command in a buffer =*mu4e-last-update*=, = which can be useful

lib/mu-server.cc

@@ -886,15 +886,20 @@ Server::Private::mkdir_handler(const Command& cmd)
 	const auto path{cmd.string_arg(":path").value_or("<error>")};
 	const auto update{cmd.boolean_arg(":update")};
 
+	if (path.find(store().root_maildir()) != 0)
+		throw Error{Error::Code::File, "maildir is not below root-maildir"};
+
 	if (auto&& res = maildir_mkdir(path, 0755, false); !res)
 		throw res.error();
 
 	/* mu4e does a lot of opportunistic 'mkdir', only send it updates when
 	 * requested */
-	if (update)
-		output_sexp(Sexp().put_props(":info", "mkdir",
-					     ":message",
-					     mu_format("{} has been created", path)));
+	if (!update)
+		return;
+
+	output_sexp(Sexp().put_props(":info", "mkdir",
+				     ":message",
+				     mu_format("{} has been created", path)));
 }
 
 void

mu4e/mu4e-folders.el

@@ -162,17 +162,6 @@ mime-type are nil."
 (defvar mu4e-maildir-list nil
   "Cached list of maildirs.")
 
-(defcustom mu4e-cache-maildir-list t
-  "Whether to cache the list of maildirs.
-Set it to t if you find that generating the list on the fly is
-too slow.
-
-If you do so, you can set `mu4e-maildir-list' to nil to force
-regenerating the cache the next time `mu4e-get-maildirs' gets
-called."
-  :type 'boolean
-  :group 'mu4e-folders)
-
 
 (defun mu4e-maildir-shortcuts ()
   "Get `mu4e-maildir-shortcuts' in the (new) format.
@@ -204,19 +193,19 @@ the result."
         (or val (mu4e-error "%S evaluates to nil" foldervar)))))
 
 (defun mu4e-get-drafts-folder (&optional msg)
-  "Get the drafts folder, optionallly based on MSG.
+  "Get the drafts folder, optionally based on MSG.
 See `mu4e-drafts-folder'." (mu4e--get-folder 'mu4e-drafts-folder msg))
 
 (defun mu4e-get-refile-folder (&optional msg)
-  "Get the folder for refiling, optionallly based on MSG.
+  "Get the folder for refiling, optionally based on MSG.
 See `mu4e-refile-folder'." (mu4e--get-folder 'mu4e-refile-folder msg))
 
 (defun mu4e-get-sent-folder (&optional msg)
-  "Get the sent folder, optionallly based on MSG.
+  "Get the sent folder, optionally based on MSG.
 See `mu4e-sent-folder'." (mu4e--get-folder 'mu4e-sent-folder msg))
 
 (defun mu4e-get-trash-folder (&optional msg)
-  "Get the trash folder, optionallly based on MSG.
+  "Get the trash folder, optionally based on MSG.
 See `mu4e-trash-folder'." (mu4e--get-folder 'mu4e-trash-folder msg))
 
 ;;; Maildirs
@@ -237,11 +226,9 @@ to create it; otherwise return nil."
   (let ((seems-to-exist (file-directory-p dir)))
     (when (or seems-to-exist
               (yes-or-no-p (mu4e-format "%s does not exist yet. Create now?" dir)))
-      ;; even when the maildir already seems to exist,
-      ;; call mkdir for a deeper check. However only get an update
-      ;; when the maildir is totally new.
+      ;; even when the maildir already seems to exist, call mkdir for a deeper
+      ;; check. However only get an update when the maildir is totally new.
       (mu4e--server-mkdir dir (not seems-to-exist))
-      (setq mu4e-maildir-list nil) ;; clear cache
       t)))
 
 (defun mu4e-get-maildirs ()

mu4e/mu4e-obsolete.el

@@ -224,5 +224,11 @@
 (define-obsolete-function-alias 'mu4e-quote-for-modeline
   'mu4e--modeline-quote-and-truncate "1.9.16")
 
+;; mu4e-folder
+(make-obsolete-variable 'mu4e-cache-maildir-list "No longer used" "1.11.15")
+
+;; mu4e.
+(make-obsolete 'mu4e-clear-caches "No longer used" "1.11.15")
+
 (provide 'mu4e-obsolete)
 ;;; mu4e-obsolete.el ends here

mu4e/mu4e-server.el

@@ -643,7 +643,13 @@ the directory time stamp."
 
 (defun mu4e--server-mkdir (path &optional update)
   "Create a new maildir-directory at filesystem PATH.
-When UPDATE is non-nil, send a update when completed."
+When UPDATE is non-nil, send a update when completed.
+PATH must be below the root-maildir."
+  ;; handle maildir cache
+  (if (not (string-prefix-p (mu4e-root-maildir) path))
+      (mu4e-error "Cannot create maildir outside root-maildir")
+    (add-to-list 'mu4e-maildir-list ;; update cache
+                 (substring path (length (mu4e-root-maildir)))))
   (mu4e--server-call-mu `(mkdir
                           :path ,path
                           :update ,(or update nil))))

mu4e/mu4e.el

@@ -160,7 +160,12 @@ Otherwise, check requirements, then start mu4e. When successful, invoke
   (when mu4e--update-timer
     (cancel-timer mu4e--update-timer)
     (setq mu4e--update-timer nil))
-  (mu4e-clear-caches)
+
+  (setq ;; clear some caches
+   mu4e-maildir-list nil
+   mu4e--contacts-set nil
+   mu4e--contacts-tstamp "0")
+
   (remove-hook 'mu4e-query-items-updated-hook #'mu4e--main-redraw)
   (remove-hook 'mu4e-query-items-updated-hook #'mu4e--modeline-update)
   (remove-hook 'mu4e-query-items-updated-hook #'mu4e--notification)
@@ -229,7 +234,8 @@ Otherwise, check requirements, then start mu4e. When successful, invoke
             mu4e-message-changed-hook)
           (unless (and (not (string= mu4e--contacts-tstamp "0"))
                        (zerop (plist-get info :updated)))
-            (mu4e--request-contacts-maybe))
+            (mu4e--request-contacts-maybe)
+            (mu4e--server-data 'maildirs)) ;; update maildir list
           (mu4e--main-redraw))))
      ((plist-get info :message)
       (mu4e-index-message "%s" (plist-get info :message))))))
@@ -253,13 +259,6 @@ chance."
   (mu4e-setq-if-nil mu4e-pong-func             #'mu4e--default-handler)
 
   (mu4e-setq-if-nil mu4e-queries-func      #'mu4e--query-items-queries-handler))
-
-(defun mu4e-clear-caches ()
-  "Clear any cached resources."
-  (setq
-   mu4e-maildir-list nil
-   mu4e--contacts-set nil
-   mu4e--contacts-tstamp "0"))
 
 ;;;
 (provide 'mu4e)