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

[Mark Walters]

On Mon, 18 Jun 2012, Jameson Graef Rollins <jrollins at finestructure.net> wrote:
> On Fri, Jun 15 2012, Jani Nikula <jani at nikula.org> wrote:
>> Add function notmuch-show-toggle-multipart-alternative to make
>> notmuch-show-all-multipart/alternative-parts buffer local, toggle its
>> value 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.
>
> This is a very cool feature.  I haven't looked closely at this but can't
> this mechanism work the same as the other show-mode toggles, like crypto
> or indenting?  I wouldn't think it would require any more extra variable
> stuff than what is used for those other toggles.
>
> Also, the *really* sweet thing would be if the toggle actually cycled
> through display of the alternatives, only displaying one at a time.
> That would be very swank.
>
> David Edmondson put together the other show-mode toggling stuff, so he
> may be able to help with this as well.

Hi

I agree with this cycling approach but I think it needs to be per
message rather than per buffer. I attach a rather hacky attempt at this
below: on minimal testing it seems to work. But the lisp is really a bit
gross. In particular  I have no idea if I should be escaping the message
ids (so this could break in unfortunate/insecure ways)

Best wishes

Mark

>From 4164456d225fca3c62bacfdc08a21cf4b32b5067 Mon Sep 17 00:00:00 2001
From: Mark Walters <markwalters1009 at gmail.com>
Date: Tue, 19 Jun 2012 07:50:17 +0100
Subject: [PATCH] first attempt at cycling multipart

---
 emacs/notmuch-show.el |   29 ++++++++++++++++++++++++++---
 1 files changed, 26 insertions(+), 3 deletions(-)

diff --git a/emacs/notmuch-show.el b/emacs/notmuch-show.el
index 0f54259..65a89fe 100644
--- a/emacs/notmuch-show.el
+++ b/emacs/notmuch-show.el
@@ -155,6 +155,10 @@ indentation."
 (make-variable-buffer-local 'notmuch-show-indent-content)
 (put 'notmuch-show-indent-content 'permanent-local t)
 
+(defvar notmuch-show-message-multipart/alternative nil)
+(make-variable-buffer-local 'notmuch-show-message-multipart/alternative)
+(put 'notmuch-show-message-multipart/alternative 'permanent-local t)
+
 (defcustom notmuch-show-stash-mlarchive-link-alist
   '(("Gmane" . "http://mid.gmane.org/")
     ("MARC" . "http://marc.info/?i=")
@@ -537,9 +541,17 @@ message at DEPTH in the current thread."
 
 (defun notmuch-show-insert-part-multipart/alternative (msg part content-type nth depth declared-type)
   (notmuch-show-insert-part-header nth declared-type content-type nil)
-  (let ((chosen-type (car (notmuch-multipart/alternative-choose (notmuch-show-multipart/*-to-list part))))
-	(inner-parts (plist-get part :content))
-	(start (point)))
+  (let* ((chosen-nth (or (lax-plist-get notmuch-show-message-multipart/alternative (plist-get msg :id)) 0))
+	 (chosen-type (nth chosen-nth
+			  (notmuch-multipart/alternative-choose (notmuch-show-multipart/*-to-list part))))
+	 (inner-parts (plist-get part :content))
+	 (start (point)))
+    ;; If we have run out of possible content-types restart from the beginning
+    (unless chosen-type
+      (setq chosen-type (car (notmuch-multipart/alternative-choose (notmuch-show-multipart/*-to-list part))))
+      (setq notmuch-show-message-multipart/alternative
+	    (lax-plist-put notmuch-show-message-multipart/alternative (plist-get msg :id) 0)))
+
     ;; This inserts all parts of the chosen type rather than just one,
     ;; but it's not clear that this is the wrong thing to do - which
     ;; should be chosen if there are more than one that match?
@@ -943,6 +955,16 @@ message at DEPTH in the current thread."
 	     "Not processing cryptographic MIME parts."))
   (notmuch-show-refresh-view))
 
+(defun notmuch-show-cycle-message-multipart ()
+  "Cycle which part to display of a multipart messageToggle the display of non-matching messages."
+  (interactive)
+  (let* ((msg-id (notmuch-show-get-message-id t))
+	 (next-part (1+ (or (lax-plist-get notmuch-show-message-multipart/alternative msg-id) 0))))
+    (setq notmuch-show-message-multipart/alternative
+	(lax-plist-put notmuch-show-message-multipart/alternative msg-id next-part))
+    (message "Cycling multipart/alternative for current message")
+    (notmuch-show-refresh-view)))
+
 (defun notmuch-show-toggle-elide-non-matching ()
   "Toggle the display of non-matching messages."
   (interactive)
@@ -1155,6 +1177,7 @@ reset based on the original query."
 	(define-key map "R" 'notmuch-show-reply)
 	(define-key map "|" 'notmuch-show-pipe-message)
 	(define-key map "w" 'notmuch-show-save-attachments)
+	(define-key map "W" 'notmuch-show-cycle-message-multipart)
 	(define-key map "V" 'notmuch-show-view-raw-message)
 	(define-key map "v" 'notmuch-show-view-all-mime-parts)
 	(define-key map "c" 'notmuch-show-stash-map)
-- 
1.7.9.1