mu4e-utils: refactor into mu4e-helpers, separate files

Usurp more of the utils code than can be re-used without further dependencies in
helpers.

Split off specific parts in their own file.

After the helper/utils changes, update the rest of mu4e to take the changes into
account.

mu4e/mu4e-main.el

@@ -25,14 +25,20 @@
 ;;; Code:
 
 (require 'smtpmail)      ;; the queueing stuff (silence elint)
-(require 'mu4e-utils)    ;; utility functions
+(require 'mu4e-helpers)    ;; utility functions
 (require 'mu4e-context)  ;; the context
+(require 'mu4e-bookmarks)
+(require 'mu4e-folders)
+(require 'mu4e-update)
+(require 'mu4e-contacts)
 (require 'mu4e-search)
 (require 'mu4e-vars)     ;; mu-wide variables
 
 (require 'cl-lib)
 
-;;; Mode
+
+
+;; Configuration
 
 (define-obsolete-variable-alias
   'mu4e-main-buffer-hide-personal-addresses
@@ -49,6 +55,37 @@ part of the personal addresses.")
   "When set to t, do not hide bookmarks or maildirs that have
 no unread messages.")
 
+
+;;; Mode
+(define-derived-mode mu4e-org-mode org-mode "mu4e:org"
+  "Major mode for mu4e documents, derived from
+  `org-mode'.")
+
+(defun mu4e-info (path)
+  "Show a buffer with the information (an org-file) at PATH."
+  (unless (file-exists-p path)
+    (mu4e-error "Cannot find %s" path))
+  (let ((curbuf (current-buffer)))
+    (find-file path)
+    (mu4e-org-mode)
+    (setq buffer-read-only t)
+    (define-key mu4e-org-mode-map (kbd "q")
+      `(lambda ()
+         (interactive)
+         (bury-buffer)
+         (switch-to-buffer ,curbuf)))))
+
+(defun mu4e-about ()
+  "Show the mu4e 'about' page."
+  (interactive)
+  (mu4e-info (concat mu4e-doc-dir "/mu4e-about.org")))
+
+(defun mu4e-news ()
+  "Show the mu4e 'about' page."
+  (interactive)
+  (mu4e-info (concat mu4e-doc-dir "/NEWS.org")))
+
+
 (defvar mu4e-main-mode-map
   (let ((map (make-sparse-keymap)))
 
@@ -85,6 +122,7 @@ no unread messages.")
         overwrite-mode 'overwrite-mode-binary)
   (mu4e-context-minor-mode)
   (mu4e-search-minor-mode)
+  (mu4e-update-minor-mode)
   (set (make-local-variable 'revert-buffer-function) #'mu4e~main-view-real))
 
 
@@ -121,15 +159,23 @@ clicked."
                        'mouse-face 'highlight newstr)
     newstr))
 
+
+
+(defun mu4e--longest-of-maildirs-and-bookmarks ()
+  "Return the length of longest name of bookmarks and maildirs."
+  (cl-loop for b in (append (mu4e-bookmarks)
+                            (mu4e--maildirs-with-query))
+           maximize (string-width (plist-get b :name))))
+
 (defun mu4e~main-bookmarks ()
   ;; TODO: it's a bit uncool to hard-code the "b" shortcut...
   (cl-loop with bmks = (mu4e-bookmarks)
-           with longest = (mu4e~longest-of-maildirs-and-bookmarks)
+           with longest = (mu4e--longest-of-maildirs-and-bookmarks)
            with queries = (mu4e-last-query-results)
            for bm in bmks
            for key = (string (plist-get bm :key))
            for name = (plist-get bm :name)
-           for query = (funcall (or mu4e-query-rewrite-function #'identity)
+           for query = (funcall (or mu4e-search-query-rewrite-function #'identity)
                                 (plist-get bm :query))
            for qcounts = (and (stringp query)
                               (cl-loop for q in queries
@@ -162,8 +208,8 @@ clicked."
 
 (defun mu4e~main-maildirs ()
   "Return a string of maildirs with their counts."
-  (cl-loop with mds = (mu4e~maildirs-with-query)
-           with longest = (mu4e~longest-of-maildirs-and-bookmarks)
+  (cl-loop with mds = (mu4e--maildirs-with-query)
+           with longest = (mu4e--longest-of-maildirs-and-bookmarks)
            with queries = (plist-get mu4e--server-props :queries)
            for m in mds
            for key = (string (plist-get m :key))
@@ -217,13 +263,15 @@ clicked."
   "The revert buffer function for `mu4e-main-mode'."
   (mu4e~main-view-real-1 'refresh))
 
+(declare-function mu4e--start "mu4e")
+
 (defun mu4e~main-view-real-1 (&optional refresh)
   "Create `mu4e-main-buffer-name' and set it up.
 When REFRESH is non nil refresh infos from server."
   (let ((inhibit-read-only t))
     ;; Maybe refresh infos from server.
     (if refresh
-        (mu4e~start 'mu4e~main-redraw-buffer)
+        (mu4e--start 'mu4e~main-redraw-buffer)
       (mu4e~main-redraw-buffer))))
 
 (defun mu4e~main-redraw-buffer ()