mu4e-modeline: refactor modeline support

Move all the modeline code to new mu4e-modeline.el, and update
mu4e-context and mu4e-headers to use it.

mu4e/meson.build

@@ -45,6 +45,7 @@ mu4e_srcs=[
   'mu4e-main.el',
   'mu4e-mark.el',
   'mu4e-message.el',
+  'mu4e-modeline.el',
   'mu4e-obsolete.el',
   'mu4e-org.el',
   'mu4e-search.el',

mu4e/mu4e-context.el

@@ -1,6 +1,6 @@
 ;;; mu4e-context.el -- part of mu4e, the mu mail user agent -*- lexical-binding: t -*-
 
-;; Copyright (C) 2015-2022 Dirk-Jan C. Binnema
+;; Copyright (C) 2015-2023 Dirk-Jan C. Binnema
 
 ;; Author: Dirk-Jan C. Binnema <djcb@djcbsoftware.nl>
 ;; Maintainer: Dirk-Jan C. Binnema <djcb@djcbsoftware.nl>
@@ -28,6 +28,7 @@
 ;;; Code:
 
 (require 'mu4e-helpers)
+(require 'mu4e-modeline)
 
 
 ;;; Configuration
@@ -82,14 +83,6 @@ none."
                     (if ctx (mu4e-context-name ctx) "<none>")))
     ctx))
 
-(defun mu4e-context-label ()
-  "Propertized string with the current context name.
-An empty string \"\" if there is none."
-  (if (mu4e-context-current)
-      (concat "[" (propertize (mu4e-quote-for-modeline
-                               (mu4e-context-name (mu4e-context-current)))
-                              'face 'mu4e-context-face) "]") ""))
-
 (cl-defstruct mu4e-context
   "A mu4e context object with the following members:
 - `name': the name of the context, eg. \"Work\" or \"Private\".
@@ -154,7 +147,7 @@ non-nil."
 
       (run-hooks 'mu4e-context-changed-hook)
       (mu4e-message "Switched context to %s" (mu4e-context-name context))
-      (force-mode-line-update))
+      (mu4e--modeline-update))
     context))
 
 (defun mu4e--context-autoswitch (&optional msg policy)
@@ -204,13 +197,6 @@ as it is."
                           (mu4e--context-ask-user "Select context: ")))
          (_ nil))))))
 
-(defun mu4e-context-in-modeline ()
-  "Display the mu4e-context (if any) in a (buffer-specific)
-global-mode-line."
-  (add-to-list
-   (make-local-variable 'global-mode-string)
-   '(:eval (mu4e-context-label))))
-
 (defmacro with-mu4e-context-vars (context &rest body)
   "Evaluate BODY, with variables let-bound for CONTEXT (if any).
 `funcall'."
@@ -221,6 +207,14 @@ global-mode-line."
          (mapcar (lambda(cell) (cdr cell)) vars)
        (eval ,@body))))
 
+(defun mu4e--context-modeline-item ()
+  "Propertized string with the current context name.
+An empty string \"\" if there is none."
+  (if (mu4e-context-current)
+      (concat "[" (propertize (mu4e-quote-for-modeline
+                               (mu4e-context-name (mu4e-context-current)))
+                              'face 'mu4e-context-face) "] " ) ""))
+
 (define-minor-mode mu4e-context-minor-mode
   "Mode for switching the mu4e context."
   :global nil
@@ -231,7 +225,8 @@ global-mode-line."
     (define-key map (kbd ";") #'mu4e-context-switch)
     map)
   :lighter ""
-  (mu4e-context-in-modeline))
+  (mu4e--modeline-register #'mu4e--context-modeline-item)
+  (mu4e--modeline-update))
 
 ;;;
 (provide 'mu4e-context)

mu4e/mu4e-headers.el

@@ -1,6 +1,6 @@
 ;;; mu4e-headers.el -- part of mu4e -*- lexical-binding: t; coding:utf-8 -*-
 
-;; Copyright (C) 2011-2022 Dirk-Jan C. Binnema
+;; Copyright (C) 2011-2023 Dirk-Jan C. Binnema
 
 ;; Author: Dirk-Jan C. Binnema <djcb@djcbsoftware.nl>
 ;; Maintainer: Dirk-Jan C. Binnema <djcb@djcbsoftware.nl>
@@ -812,7 +812,7 @@ true, do *not* update the query history stack."
           (mu4e--search-push-query mu4e--search-last-query 'past)))
       (setq mu4e--search-last-query rewritten-expr)
       (setq list-buffers-directory rewritten-expr)
-      (mu4e~headers-update-mode-line))
+      (mu4e--modeline-update))
 
     ;; when the buffer is already visible, select it; otherwise,
     ;; switch to it.
@@ -1178,7 +1178,10 @@ The following specs are supported:
   (mu4e-context-minor-mode)
   (mu4e-update-minor-mode)
   (mu4e-search-minor-mode)
-  (hl-line-mode 1))
+  (hl-line-mode 1)
+
+  (mu4e--modeline-register #'mu4e~headers-modeline-item)
+  (mu4e--modeline-update))
 
 ;;; Highlighting
 
@@ -1244,7 +1247,7 @@ message plist, or nil if not found."
 
 ;;; Queries & searching
 (defvar mu4e~headers-mode-line-label "")
-(defun mu4e~headers-update-mode-line ()
+(defun mu4e~headers-modeline-item ()
   "Update mode-line settings."
   (let* ((flagstr
           (mapconcat
@@ -1258,30 +1261,8 @@ message plist, or nil if not found."
              (,mu4e-search-skip-duplicates
               . ,mu4e-headers-skip-duplicates-label)
              (,mu4e-search-hide-enabled    . ,mu4e-headers-hide-label))
-           ""))
-         (name "mu4e-headers"))
-
-      (setq mode-name name)
-      (setq mu4e~headers-mode-line-label
-            (concat flagstr " " mu4e--search-last-query))
-
-      (make-local-variable 'global-mode-string)
-
-      (add-to-list 'global-mode-string
-                   `(:eval
-                     (concat
-                      (propertize
-                       (mu4e-quote-for-modeline ,mu4e~headers-mode-line-label)
-                       'face 'mu4e-modeline-face)
-                      " "
-                      (if (and mu4e-display-update-status-in-modeline
-                               (buffer-live-p mu4e--update-buffer)
-                               (process-live-p (get-buffer-process
-                                                mu4e--update-buffer)))
-                          (propertize " (updating)" 'face 'mu4e-modeline-face)
-                        ""))))))
-
-
+           "")))
+    (concat flagstr " " mu4e--search-last-query)))
 
 ;;; Search-based marking
 

mu4e/mu4e-modeline.el

@@ -0,0 +1,79 @@
+;;; mu4e-modeline.el -- part of mu4e  -*- lexical-binding: t -*-
+
+;; Copyright (C) 2023 Dirk-Jan C. Binnema
+
+;; Author: Dirk-Jan C. Binnema <djcb@djcbsoftware.nl>
+;; Maintainer: Dirk-Jan C. Binnema <djcb@djcbsoftware.nl>
+
+;; This file is not part of GNU Emacs.
+
+;; mu4e is free software: you can redistribute it and/or modify
+;; it under the terms of the GNU General Public License as published by
+;; the Free Software Foundation, either version 3 of the License, or
+;; (at your option) any later version.
+
+;; mu4e is distributed in the hope that it will be useful,
+;; but WITHOUT ANY WARRANTY; without even the implied warranty of
+;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+;; GNU General Public License for more details.
+
+;; You should have received a copy of the GNU General Public License
+;; along with mu4e.  If not, see <http://www.gnu.org/licenses/>.
+
+;;; Commentary:
+
+;; This file contains functionality for putting mu4e-related information
+;; in the emacs modeline, both buffer-specific and globally.
+
+;;; Code:
+
+(require 'cl-lib)
+
+(defvar-local mu4e--modeline-buffer-items nil
+  "List of buffer-local items for the mu4e modeline.
+Each element is function that evaluates to a string.")
+
+(defvar mu4e--modeline-global-items nil
+  "List of items for the global modeline.
+Each element is function that evaluates to a string.")
+
+(defun mu4e--modeline-register (func &optional global)
+  "Register a function for calculating some mu4e modeline part.
+If GLOBAL is non-nil, add to the global-modeline; otherwise use
+the buffer-local one."
+  (add-to-list
+   (if global 'mu4e--modeline-global-items 'mu4e--modeline-buffer-items)
+   func))
+
+(defvar mu4e--modeline-item nil
+  "Mu4e item for the global-mode-line.")
+
+(defun mu4e--modeline-string ()
+  "Calculate the current mu4e modeline string."
+  (mapconcat
+   (lambda (item)
+     (if (functionp item)
+         (or (funcall item) "")
+       ""))
+   (append mu4e--modeline-buffer-items mu4e--modeline-global-items) " "))
+
+(define-minor-mode mu4e-modeline-mode
+  "Minor mode for showing mu4e information on the modeline."
+  ;; This is a bit special 'global' mode, since it consists of both
+  ;; buffer-specific parts (mu4e--modeline-buffer-items) and global items
+  ;; (mu4e--modeline-global-items).
+  :global t
+  :group 'mu4e
+  :lighter nil
+  (if mu4e-modeline-mode
+      (progn
+        (setq mu4e--modeline-item '(:eval (mu4e--modeline-string)))
+        (add-to-list 'global-mode-string mu4e--modeline-item))
+    (progn
+      (setq global-mode-string
+            (seq-remove (lambda (item) (equal item mu4e--modeline-item))
+                        global-mode-string))))
+  (force-mode-line-update))
+
+(provide 'mu4e-modeline)
+;; mu4e-modeline.el ends here

mu4e/mu4e.el

@@ -1,6 +1,6 @@
 ;;; mu4e.el --- part of mu4e, the mu mail user agent -*- lexical-binding: t -*-
 
-;; Copyright (C) 2011-2022 Dirk-Jan C. Binnema
+;; Copyright (C) 2011-2023 Dirk-Jan C. Binnema
 
 ;; Author: Dirk-Jan C. Binnema <djcb@djcbsoftware.nl>
 ;; Maintainer: Dirk-Jan C. Binnema <djcb@djcbsoftware.nl>
@@ -48,6 +48,11 @@
   :type 'boolean
   :group 'mu4e)
 
+(defcustom mu4e-modeline-support t
+  "Support for shoiwing information in the modeline."
+  :type 'boolean
+  :group 'mu4e)
+
 (defcustom mu4e-org-support t
   "Support Org-mode links."
   :type 'boolean