This adds the actual code to do the lazy insertion of hidden parts.
We use a memory inefficient but simple method: when we come to insert
the part if it is hidden we just store all of the arguments to the
part insertion function as a button property. This means when we want
to show the part we can just resume where we left off.
One thing is that we can't tell if a lazy part will produce text until
we try to render it so when unhiding a part we check to see if it
rendered; if not we invoke the default part handler (e.g. an external
viewer).
---
emacs/notmuch-show.el | 51 ++++++++++++++++++++++++++++++++++++++++++-------
1 file changed, 44 insertions(+), 7 deletions(-)
diff --git a/emacs/notmuch-show.el b/emacs/notmuch-show.el
index 89199e8..4999b94 100644
--- a/emacs/notmuch-show.el
+++ b/emacs/notmuch-show.el
@@ -550,12 +550,14 @@ message at DEPTH in the current thread."
(let ((handle (mm-make-handle (current-buffer) (list content-type))))
(mm-pipe-part handle))))
-;; This is taken from notmuch-wash: maybe it should be unified?
(defun notmuch-show-toggle-part-invisibility (&optional button)
(interactive)
(let* ((button (or button (button-at (point))))
- (overlay (button-get button 'overlay)))
- (when overlay
+ (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))
@@ -569,7 +571,15 @@ message at DEPTH in the current thread."
(move-overlay button new-start (point))
(delete-region (point) old-end))
(goto-char (min old-point (1- (button-end button))))
- (overlay-put overlay 'invisible (not show))))))
+ ;; 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)))))
(defun notmuch-show-multipart/*-to-list (part)
(mapcar (lambda (inner-part) (plist-get inner-part :content-type))
@@ -865,6 +875,27 @@ message at DEPTH in the current thread."
;; Return true if we created an overlay.
t))
+(defun notmuch-show-lazy-part (part-args button)
+ ;; Insert the lazy part after the button for the part.
+ (save-excursion
+ (goto-char (1+ (button-end button)))
+ (let* ((inhibit-read-only t)
+ ;; We need to use markers for the start and end of the part
+ ;; because the part insertion functions do not guarantee
+ ;; to leave point at the end of the part.
+ (part-beg (copy-marker (point) nil))
+ (part-end (copy-marker (point) t))
+ ;; We have to save the depth as we can't find the depth
+ ;; when narrowed.
+ (depth (notmuch-show-get-depth)))
+ (save-restriction
+ (narrow-to-region part-beg part-end)
+ (delete-region part-beg part-end)
+ (apply #'notmuch-show-insert-bodypart-internal part-args)
+ (indent-rigidly part-beg part-end depth))
+ ;; Create the overlay. If the lazy-part turned out to be empty/not
+ ;; showable this returns nil.
+ (notmuch-show-create-part-overlays button part-beg part-end))))
(defun notmuch-show-insert-bodypart (msg part depth &optional hide)
"Insert the body part PART at depth DEPTH in the current thread.
@@ -883,7 +914,11 @@ If HIDE is non-nil then initially hide this part."
(notmuch-show-insert-part-header nth mime-type content-type
(plist-get part :filename))))
(beg (point)))
- (notmuch-show-insert-bodypart-internal msg part mime-type nth depth button)
+ (if (not hide)
+ (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)))
+
;; Some of the body part handlers leave point somewhere up in the
;; part, so we make sure that we're down at the end.
(goto-char (point-max))
@@ -2002,8 +2037,10 @@ the user (see
`notmuch-show-stash-mlarchive-link-alist')."
(defun notmuch-show-part-button-default (&optional button)
(interactive)
(let ((button (or button (button-at (point)))))
- (if (button-get button 'overlay)
- (notmuch-show-toggle-part-invisibility button)
+ ;; Try to toggle the part, if that fails then call the default
+ ;; action. The toggle fails if the part has no emacs renderable
+ ;; content.
+ (unless (notmuch-show-toggle-part-invisibility button)
(notmuch-show-part-button-internal button
notmuch-show-part-button-default-action))))
(defun notmuch-show-part-button-save (&optional button)
--
1.7.10.4
