[PATCH v4 2/7] emacs/show: Accommodate the lack of part header buttons

[David Edmondson]

On Sat, Nov 07 2015, Mark Walters wrote:
> From: David Edmondson <dme at dme.org>
>
> Various pieces of code assumed (reasonably) that part header buttons
> are present. Modify them to avoid problems if no part headers were
> inserted.

This looks fine.

> ---
>  emacs/notmuch-show.el | 88 ++++++++++++++++++++++++++++-----------------------
>  1 file changed, 48 insertions(+), 40 deletions(-)
>
> diff --git a/emacs/notmuch-show.el b/emacs/notmuch-show.el
> index 47a02e5..9fc79e0 100644
> --- a/emacs/notmuch-show.el
> +++ b/emacs/notmuch-show.el
> @@ -509,36 +509,37 @@ (defun notmuch-show-insert-part-header (nth content-type declared-type &optional
>  
>  (defun notmuch-show-toggle-part-invisibility (&optional button)
>    (interactive)
> -  (let* ((button (or button (button-at (point))))
> -	 (overlay (button-get button 'overlay))
> -	 (lazy-part (button-get button :notmuch-lazy-part)))
> -    ;; We have a part to toggle if there is an overlay or if there is a lazy part.
> -    ;; If neither is present we cannot toggle the part so we just return nil.
> -    (when (or overlay lazy-part)
> -      (let* ((show (button-get button :notmuch-part-hidden))
> -	     (new-start (button-start button))
> -	     (button-label (button-get button :base-label))
> -	     (old-point (point))
> -	     (properties (text-properties-at (button-start button)))
> -	     (inhibit-read-only t))
> -	;; Toggle the button itself.
> -	(button-put button :notmuch-part-hidden (not show))
> -	(goto-char new-start)
> -	(insert "[ " button-label (if show " ]" " (hidden) ]"))
> -	(set-text-properties new-start (point) properties)
> -	(let ((old-end (button-end button)))
> -	  (move-overlay button new-start (point))
> -	  (delete-region (point) old-end))
> -	(goto-char (min old-point (1- (button-end button))))
> -	;; Return nil if there is a lazy-part, it is empty, and we are
> -	;; trying to show it.  In all other cases return t.
> -	(if lazy-part
> -	    (when show
> -	      (button-put button :notmuch-lazy-part nil)
> -	      (notmuch-show-lazy-part lazy-part button))
> -	  ;; else there must be an overlay.
> -	  (overlay-put overlay 'invisible (not show))
> -	  t)))))
> +  (let ((button (or button (button-at (point)))))
> +    (when button
> +      (let ((overlay (button-get button 'overlay))
> +	    (lazy-part (button-get button :notmuch-lazy-part)))
> +	;; We have a part to toggle if there is an overlay or if there is a lazy part.
> +	;; If neither is present we cannot toggle the part so we just return nil.
> +	(when (or overlay lazy-part)
> +	  (let* ((show (button-get button :notmuch-part-hidden))
> +		 (new-start (button-start button))
> +		 (button-label (button-get button :base-label))
> +		 (old-point (point))
> +		 (properties (text-properties-at (button-start button)))
> +		 (inhibit-read-only t))
> +	    ;; Toggle the button itself.
> +	    (button-put button :notmuch-part-hidden (not show))
> +	    (goto-char new-start)
> +	    (insert "[ " button-label (if show " ]" " (hidden) ]"))
> +	    (set-text-properties new-start (point) properties)
> +	    (let ((old-end (button-end button)))
> +	      (move-overlay button new-start (point))
> +	      (delete-region (point) old-end))
> +	    (goto-char (min old-point (1- (button-end button))))
> +	    ;; Return nil if there is a lazy-part, it is empty, and we are
> +	    ;; trying to show it.  In all other cases return t.
> +	    (if lazy-part
> +		(when show
> +		  (button-put button :notmuch-lazy-part nil)
> +		  (notmuch-show-lazy-part lazy-part button))
> +	      ;; else there must be an overlay.
> +	      (overlay-put overlay 'invisible (not show))
> +	      t)))))))
>  
>  ;; Part content ID handling
>  
> @@ -647,14 +648,17 @@ (defun notmuch-show-insert-part-multipart/related (msg part content-type nth dep
>    t)
>  
>  (defun notmuch-show-insert-part-multipart/signed (msg part content-type nth depth button)
> -  (button-put button 'face 'notmuch-crypto-part-header)
> -  ;; add signature status button if sigstatus provided
> +  (when button
> +    (button-put button 'face 'notmuch-crypto-part-header))
> +  ;; Add signature status button if sigstatus provided.
>    (if (plist-member part :sigstatus)
>        (let* ((from (notmuch-show-get-header :From msg))
>  	     (sigstatus (car (plist-get part :sigstatus))))
>  	(notmuch-crypto-insert-sigstatus-button sigstatus from))
> -    ;; if we're not adding sigstatus, tell the user how they can get it
> -    (button-put button 'help-echo "Set notmuch-crypto-process-mime to process cryptographic MIME parts."))
> +    ;; If we're not adding the signature status, tell the user how
> +    ;; they can get it.
> +    (when button
> +      (button-put button 'help-echo "Set notmuch-crypto-process-mime to process cryptographic MIME parts.")))
>  
>    (let ((inner-parts (plist-get part :content))
>  	(start (point)))
> @@ -668,17 +672,20 @@ (defun notmuch-show-insert-part-multipart/signed (msg part content-type nth dept
>    t)
>  
>  (defun notmuch-show-insert-part-multipart/encrypted (msg part content-type nth depth button)
> -  (button-put button 'face 'notmuch-crypto-part-header)
> -  ;; add encryption status button if encstatus specified
> +  (when button
> +    (button-put button 'face 'notmuch-crypto-part-header))
> +  ;; Add encryption status button if encryption status is specified.
>    (if (plist-member part :encstatus)
>        (let ((encstatus (car (plist-get part :encstatus))))
>  	(notmuch-crypto-insert-encstatus-button encstatus)
> -	;; add signature status button if sigstatus specified
> +	;; Add signature status button if signature status is
> +	;; specified.
>  	(if (plist-member part :sigstatus)
>  	    (let* ((from (notmuch-show-get-header :From msg))
>  		   (sigstatus (car (plist-get part :sigstatus))))
>  	      (notmuch-crypto-insert-sigstatus-button sigstatus from))))
> -    ;; if we're not adding encstatus, tell the user how they can get it
> +    ;; If we're not adding the encryption status, tell the user how
> +    ;; they can get it.
>      (button-put button 'help-echo "Set notmuch-crypto-process-mime to process cryptographic MIME parts."))
>  
>    (let ((inner-parts (plist-get part :content))
> @@ -977,8 +984,9 @@ (defun notmuch-show-insert-bodypart (msg part depth &optional hide)
>  
>      (if show-part
>          (notmuch-show-insert-bodypart-internal msg part mime-type nth depth button)
> -      (button-put button :notmuch-lazy-part
> -                  (list msg part mime-type nth depth button)))
> +      (when button
> +	(button-put button :notmuch-lazy-part
> +		    (list msg part mime-type nth depth button))))
>  
>      ;; Some of the body part handlers leave point somewhere up in the
>      ;; part, so we make sure that we're down at the end.
> -- 
> 2.1.4