[PATCH v2] emacs: add function to toggle display of all multipart/alternative parts

[Jani Nikula <jani@nikula.org>]

Add function notmuch-show-toggle-multipart-alternative to toggle the
value of notmuch-show-all-multipart/alternative-parts variable in the
buffer, and redisplay the thread with either all or preferred
alternative parts expanded.

A small wrinkle is that in order to make the variable survive
notmuch-show-refresh-view (which is required for expanding/collapsing
the parts, but ends up calling kill-all-local-variables through
notmuch-show-mode) it is necessary to give it the permanent-local
property.
---
 emacs/notmuch-show.el |   12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/emacs/notmuch-show.el b/emacs/notmuch-show.el
index 36cad93..4d3f03f 100644
--- a/emacs/notmuch-show.el
+++ b/emacs/notmuch-show.el
@@ -98,6 +98,18 @@ any given message."
   "Should all parts of multipart/alternative parts be shown?"
   :type 'boolean
   :group 'notmuch-show)
+(make-variable-buffer-local 'notmuch-show-all-multipart/alternative-parts)
+(put 'notmuch-show-all-multipart/alternative-parts 'permanent-local t)
+
+(defun notmuch-show-toggle-multipart-alternative ()
+  "Toggle the display of all multipart/alternative parts."
+  (interactive)
+  (setq notmuch-show-all-multipart/alternative-parts
+	(not notmuch-show-all-multipart/alternative-parts))
+  (message (if notmuch-show-all-multipart/alternative-parts
+	       "Showing all multipart/alternative parts."
+	     "Showing preferred multipart/alternative part."))
+  (notmuch-show-refresh-view))
 
 (defcustom notmuch-show-indent-messages-width 1
   "Width of message indentation in threads.
-- 
1.7.9.5