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

[Jani Nikula]

On Fri, 10 Aug 2012, Mark Walters <markwalters1009 at gmail.com> wrote:
> Some messages are sent as multipart/alternative but the alternatives
> contain different information. This allows the user to cycle which
> part to view. By default this is bound to 'W'.
> ---
>
> On Thu, 09 Aug 2012, Jameson Graef Rollins <jrollins at finestructure.net> wrote:
>> On Mon, Jun 18 2012, Mark Walters <markwalters1009 at gmail.com> wrote:
>>> 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)
>>
>> Thanks to broken Apple mail clients, I'm getting more and more messages
>> that have attachments hidden in multipart/"alternatives" to text/plain
>> parts.  So I would really like to revive this patch.
>>
>> I just tested it and it still applies to current master, and actually
>> seems to work great.  'W' cycles through which part is displayed in the
>> current message.  Pretty much exactly what I want.
>>
>> Mark seems to think this patch is less than ideal.  One issue is that
>> it's trying to store a setting for a single displayed message in a
>> variable of full buffer scope.  So he's storing a list of message ids
>> there:
>>
>>> +(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)
>> ...
>>> +	    (lax-plist-put notmuch-show-message-multipart/alternative (plist-get msg :id) 0)))
>>
>> I can see that might get a little hairy.  Can any elisp experts out
>> there think of a better way to do this?  (actually, this is making me
>> again want a show mode that only displays one message at a time (which I
>> guess means I need to try pick again)).
>
> This version at least uses the notmuch escaping for message-id which
> makes me a bit happier: it probably doesn't have any nasty security
> flaws. I do still feel that the lisp is a bit ugly though.
>
> Incidentally, Austin suggested I might be able to use text-properties
> rather than this big list. Unfortunately, I use
> notmuch-show-refresh-view to do the redisplay and that deletes all
> text-properties.
>
> Note this is not very well tested as I have very few
> multipart/alternative messages.

How would this work together with something like [1] (rationale in [2])?

[1] id:"ab777cf0fa83778d3399ac52094df9230738819d.1328798471.git.jani at nikula.org"
[2] id:"cover.1328719309.git.jani at nikula.org"

If you introduce a mechanism to store the state, could it be extended to
store the state of each individual part? That, in turn, could be used to
add support for expanding/collapsing each alternative part through the
buttons (e.g. [ text/html (not shown) ]). Each button could toggle the
state of the part, and refresh buffer.

I guess basically the above are related. If you stored a list of parts
to display per each message id, the initial list could be created based
on customized regexps, the buttons could be used for toggling each
individual part (adding/removing the type from the list), and you could
have a function that would cycle the list to your heart's content.

BR,
Jani.



>
> Best wishes
>
> Mark
>
>
>  emacs/notmuch-show.el |   31 ++++++++++++++++++++++++++++---
>  1 files changed, 28 insertions(+), 3 deletions(-)
>
> diff --git a/emacs/notmuch-show.el b/emacs/notmuch-show.el
> index dcfc190..dee6b85 100644
> --- a/emacs/notmuch-show.el
> +++ b/emacs/notmuch-show.el
> @@ -154,6 +154,10 @@ indentation."
>  (make-variable-buffer-local 'notmuch-show-indent-content)
>  (put 'notmuch-show-indent-content 'permanent-local t)
>  
> +(defvar notmuch-show-message-multipart/alternative-display-part nil)
> +(make-variable-buffer-local 'notmuch-show-message-multipart/alternative-display-part)
> +(put 'notmuch-show-message-multipart/alternative-display-part 'permanent-local t)
> +
>  (defcustom notmuch-show-stash-mlarchive-link-alist
>    '(("Gmane" . "http://mid.gmane.org/")
>      ("MARC" . "http://marc.info/?i=")
> @@ -536,9 +540,19 @@ 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-display-part
> +					(notmuch-id-to-query (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-display-part
> +	    (lax-plist-put notmuch-show-message-multipart/alternative-display-part
> +			   (notmuch-id-to-query (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?
> @@ -942,6 +956,16 @@ 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))
> +	 (next-part (1+ (or (lax-plist-get notmuch-show-message-multipart/alternative-display-part msg-id) 0))))
> +    (setq notmuch-show-message-multipart/alternative-display-part
> +	(lax-plist-put notmuch-show-message-multipart/alternative-display-part 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)
> @@ -1151,6 +1175,7 @@ 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